Regulatory Matters

12 Months Ended

Dec. 31, 2017

Regulated Operations [Abstract]

Regulatory Matters

REGULATORY MATTERS

REGULATORY ASSETS AND LIABILITIES

The Duke Energy Registrants record regulatory assets and liabilities that result from the ratemaking process. See Note 1 for further information.

The following tables present the regulatory assets and liabilities recorded on the Consolidated Balance Sheets of Duke Energy and Progress Energy. See separate tables below for balances by individual registrant.

	Duke Energy				Progress Energy
	December 31,				December 31,
(in millions)	2017		2016		2017		2016
Regulatory Assets
AROs – coal ash	$	4,025	$	3,761	$	1,984	$	1,830
AROs – nuclear and other	852		684		655		569
Accrued pension and OPEB	2,249		2,387		906		882
Retired generation facilities	480		534		386		422
Debt fair value adjustment	1,197		1,313		—		—
Net regulatory asset related to income taxes	—		894		—		231
Storm cost deferrals	531		153		526		148
Nuclear asset securitized balance, net	1,142		1,193		1,142		1,193
Hedge costs deferrals	234		217		94		91
Derivatives – natural gas supply contracts	142		187		—		—
Demand side management (DSM)/Energy efficiency (EE)	530		407		281		278
Grid modernization	39		65		—		—
Vacation accrual	213		196		42		38
Deferred fuel and purchased power	507		156		349		111
Nuclear deferral	119		226		35		134
Post-in-service carrying costs (PISCC) and deferred operating expenses	366		413		38		42
Transmission expansion obligation	46		71		—		—
Manufactured gas plant (MGP)	91		99		—		—
Advanced metering infrastructure (AMI)	362		218		150		—
NCEMPA deferrals	53		51		53		51
East Bend deferrals	45		32		—		—
Deferred pipeline integrity costs	54		36		—		—
Amounts due from customers	64		66		—		—
Other	538		542		110		103
Total regulatory assets	13,879		13,901		6,751		6,123
Less: current portion	1,437		1,023		741		401
Total noncurrent regulatory assets	$	12,442	$	12,878	$	6,010	$	5,722
Regulatory Liabilities
Costs of removal	$	5,968	$	5,613	$	2,537	$	2,198
ARO – nuclear and other	806		461		—		—
Net regulatory liability related to income taxes	8,113		—		2,802		—
Amounts to be refunded to customers	10		45		—		—
Storm reserve	20		83		—		60
Accrued pension and OPEB	146		174		—		—
Deferred fuel and purchased power	47		192		1		81
Other	622		722		179		245
Total regulatory liabilities	15,732		7,290		5,519		2,584
Less: current portion	402		409		213		189
Total noncurrent regulatory liabilities	$	15,330	$	6,881	$	5,306	$	2,395

Descriptions of regulatory assets and liabilities summarized in the tables above and below follow. See tables below for recovery and amortization periods at the separate registrants.

AROs – coal ash. Represents deferred depreciation and accretion related to the legal obligation to close ash basins. The costs are deferred until recovery treatment has been determined. See Notes 1 and 9 for additional information.

AROs – nuclear and other. Represents regulatory assets or liabilities, including deferred depreciation and accretion, related to legal obligations associated with the future retirement of property, plant and equipment, excluding amounts related to coal ash. The AROs relate primarily to decommissioning nuclear power facilities. The amounts also include certain deferred gains and losses on NDTF investments. See Notes 1 and 9 for additional information.

Accrued pension and OPEB. Accrued pension and other post-retirement benefit obligations (OPEB) represent regulatory assets and liabilities related to each of the Duke Energy Registrants’ respective shares of unrecognized actuarial gains and losses and unrecognized prior service cost and credit attributable to Duke Energy’s pension plans and OPEB plans. The regulatory asset or liability is amortized with the recognition of actuarial gains and losses and prior service cost and credit to net periodic benefit costs for pension and OPEB plans. The accrued pension and OPEB regulatory asset is expected to be recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 21 for additional detail.

Retired generation facilities. Represents amounts to be recovered for facilities that have been retired and are probable of recovery.

Debt fair value adjustment. Purchase accounting adjustments recorded to state the carrying value of Progress Energy and Piedmont at fair value in connection with the 2012 and 2016 mergers, respectively. Amount is amortized over the life of the related debt.

Net regulatory asset or liability related to income taxes. Amounts for all registrants include regulatory liabilities related primarily to impacts from the Tax Act. See Note 22 for additional information. Amounts have no immediate impact on rate base as regulatory assets are offset by deferred tax liabilities.

Storm cost deferrals. Represents deferred incremental costs incurred related to extraordinary weather-related events.

Nuclear asset securitized balance, net.Represents the balance associated with Crystal River Unit 3 retirement approved for recovery by the FPSC on September 15, 2015, and the upfront financing costs securitized in 2016 with issuance of the associated bonds. The regulatory asset balance is net of the AFUDC equity portion.

Hedge costs and other deferrals. Amounts relate to unrealized gains and losses on derivatives recorded as a regulatory asset or liability, respectively, until the contracts are settled.

Derivatives – natural gas supply contracts. Represents costs for certain long-dated, fixed quantity forward gas supply contracts, which are recoverable through PGA clauses.

DSM/EE. Deferred costs related to various DSM and EE programs recoverable through various mechanisms.

Grid modernization. Amounts represent deferred depreciation and operating expenses as well as carrying costs on the portion of capital expenditures placed in service but not yet reflected in retail rates as plant in service. 

Vacation accrual. Generally recovered within one year.

Deferred fuel and purchased power. Represents certain energy-related costs that are recoverable or refundable as approved by the applicable regulatory body.

Nuclear deferral. Includes amounts related to levelizing nuclear plant outage costs, which allows for the recognition of nuclear outage expenses over the refueling cycle rather than when the outage occurs, resulting in the deferral of operations and maintenance costs associated with refueling.

Post-in-service carrying costs and deferred operating expenses. Represents deferred depreciation and operating expenses as well as carrying costs on the portion of capital expenditures placed in service but not yet reflected in retail rates as plant in service.

Gasification services agreement buyout. The IURC authorized Duke Energy Indiana to recover costs incurred to buy out a gasification services agreement, including carrying costs through 2017.

Transmission expansion obligation. Represents transmission expansion obligations related to Duke Energy Ohio’s withdrawal from Midcontinent Independent System Operator, Inc. (MISO).

MGP. Represents remediation costs incurred at former MGP sites and the deferral of costs to be incurred at the East End and West End sites through 2019.

AMI. Represents deferred costs related to the installation of AMI meters and remaining net book value of non-AMI meters to be replaced at Duke Energy Carolinas, net book value of existing meters at Duke Energy Florida, Duke Energy Progress and Duke Energy Ohio and expected future recovery of net book value of electromechanical meters that have been replaced with AMI meters at Duke Energy Indiana. 

NCEMPA deferrals. Represents retail allocated cost deferrals and returns associated with the additional ownership interest in assets acquired from NCEMPA in 2015.

East Bend deferrals. Represents both deferred operating expenses and deferred depreciation as well as carrying costs on the portion of East Bend Generating Station (East Bend) that was acquired from Dayton Power and Light and that had been previously operated as a jointly owned facility.

Deferred pipeline integrity costs. Represents pipeline integrity management costs in compliance with federal regulations recovered through a rider mechanism.

Amounts due from customers. Relates primarily to margin decoupling and IMR recovery mechanisms. 

Costs of removal. Represents funds received from customers to cover the future removal of property, plant and equipment from retired or abandoned sites as property is retired. Also includes certain deferred gains on NDTF investments.

Amounts to be refunded to customers. Represents required rate reductions to retail customers by the applicable regulatory body.

Storm reserve. Amounts are used to offset future incurred costs for named storms as approved by regulatory commissions.

RESTRICTIONS ON THE ABILITY OF CERTAIN SUBSIDIARIES TO MAKE DIVIDENDS, ADVANCES AND LOANS TO DUKE ENERGY

As a condition to the approval of merger transactions, the NCUC, PSCSC, PUCO, KPSC and IURC imposed conditions on the ability of Duke Energy Carolinas, Duke Energy Progress, Duke Energy Ohio, Duke Energy Kentucky, Duke Energy Indiana and Piedmont to transfer funds to Duke Energy through loans or advances, as well as restricted amounts available to pay dividends to Duke Energy. Certain subsidiaries may transfer funds to the parent by obtaining approval of the respective state regulatory commissions. These conditions imposed restrictions on the ability of the public utility subsidiaries to pay cash dividends as discussed below.

Duke Energy Progress and Duke Energy Florida also have restrictions imposed by their first mortgage bond indentures, which, in certain circumstances, limit their ability to make cash dividends or distributions on common stock. Amounts restricted as a result of these provisions were not material at December 31, 2017.

Additionally, certain other subsidiaries of Duke Energy have restrictions on their ability to dividend, loan or advance funds to Duke Energy due to specific legal or regulatory restrictions, including, but not limited to, minimum working capital and tangible net worth requirements.

The restrictions discussed below were less than 25 percent of Duke Energy's and Progress Energy's net assets at December 31, 2017.

Duke Energy Carolinas

Duke Energy Carolinas must limit cumulative distributions subsequent to mergers to (i) the amount of retained earnings on the day prior to the closing of the mergers, plus (ii) any future earnings recorded.

Duke Energy Progress

Duke Energy Progress must limit cumulative distributions subsequent to the mergers between Duke Energy and Progress Energy and Duke Energy and Piedmont to (i) the amount of retained earnings on the day prior to the closing of the respective mergers, plus (ii) any future earnings recorded.

Duke Energy Ohio

Duke Energy Ohio will not declare and pay dividends out of capital or unearned surplus without the prior authorization of the PUCO. Duke Energy Ohio received FERC and PUCO approval to pay dividends from its equity accounts that are reflective of the amount that it would have in its retained earnings account had push-down accounting for the Cinergy Corp. (Cinergy) merger not been applied to Duke Energy Ohio’s balance sheet. The conditions include a commitment from Duke Energy Ohio that equity, adjusted to remove the impacts of push-down accounting, will not fall below 30 percent of total capital.

Duke Energy Kentucky is required to pay dividends solely out of retained earnings and to maintain a minimum of 35 percent equity in its capital structure.

Duke Energy Indiana

Duke Energy Indiana must limit cumulative distributions subsequent to the merger between Duke Energy and Cinergy to (i) the amount of retained earnings on the day prior to the closing of the merger, plus (ii) any future earnings recorded. In addition, Duke Energy Indiana will not declare and pay dividends out of capital or unearned surplus without prior authorization of the IURC.

Piedmont

Piedmont must limit cumulative distributions subsequent to the acquisition of Piedmont by Duke Energy to (i) the amount of retained earnings on the day prior to the closing of the merger, plus (ii) any future earnings recorded.

RATE RELATED INFORMATION

The NCUC, PSCSC, FPSC, IURC, PUCO, TPUC and KPSC approve rates for retail electric and natural gas services within their states. The FERC approves rates for electric sales to wholesale customers served under cost-based rates (excluding Ohio and Indiana), as well as sales of transmission service. The FERC also regulates certification and siting of new interstate natural gas pipeline projects.

All Registrants

Tax Act Impacts

On December 22, 2017, President Trump signed the Tax Act into law, which, among other provisions, reduces the maximum federal corporate income tax rate from 35 percent to 21 percent, effective January 1, 2018. As a result of the Tax Act, the Subsidiary Registrants revalued their deferred tax assets and deferred tax liabilities, as of December 31, 2017, to account for the future impact of lower corporate tax rates on these deferred tax amounts. For the Subsidiary Registrants regulated operations, where the reduction is expected to be accounted for and applied to customers’ rates in future commission proceedings, including rate proceedings, the net remeasurement has been deferred as a regulatory liability. Each of the Subsidiary Registrant's regulatory commissions is reviewing the Tax Act to determine the potential impacts on customer rates. Beginning in January 2018, the Subsidiary Registrants will defer the estimated ongoing impacts of the Tax Act that are expected to be returned to customers. See Note 22 for additional information.

Duke Energy Carolinas and Duke Energy Progress

Ash Basin Closure Costs Deferral

On December 30, 2016, Duke Energy Carolinas and Duke Energy Progress filed a joint petition with the NCUC seeking an accounting order authorizing deferral of certain costs incurred in connection with federal and state environmental remediation requirements related to the permanent closure of ash basins and other ash storage units at coal-fired generating facilities that have provided or are providing generation to customers located in North Carolina. Initial comments were received in March 2017, and reply comments were filed on April 19, 2017. The NCUC has consolidated Duke Energy Carolinas' and Duke Energy Progress’ coal ash deferral requests into their respective general rate case dockets for decision. See "2017 North Carolina Rate Case" sections below for additional discussion. Duke Energy Carolinas and Duke Energy Progress cannot predict the outcome of this matter.

Duke Energy Carolinas

Regulatory Assets and Liabilities

The following tables present the regulatory assets and liabilities recorded on Duke Energy Carolinas' Consolidated Balance Sheets.

	December 31,				Earns/Pays	Recovery/Refund
(in millions)	2017		2016		a Return	Period Ends
Regulatory Assets(a)
AROs - coal ash	$	1,645	$	1,536	(i)	(b)
AROs - nuclear and other	—		9
Accrued pension and OPEB	410		481			(j)
Retired generation facilities(c)	29		39		X	2023
Net regulatory asset related to income taxes(d)	—		484
Hedge costs deferrals(c)	109		93		X	2041
DSM/EE	210		122		(h)	(h)
Vacation accrual	83		76		(e)	2018
Deferred fuel and purchased power	140		—		(f)	2018
Nuclear deferral	84		92			2019
PISCC(c)	35		70		X	(b)
AMI	185		172		X	(b)
Other	222		223			(b)
Total regulatory assets	3,152		3,397
Less: current portion	299		238
Total noncurrent regulatory assets	$	2,853	$	3,159
Regulatory Liabilities(a)
Costs of removal(c)	$	2,054	$	2,015	X	(g)
ARO - nuclear and other	806		461			(b)
Net regulatory liability related to income taxes(d)	3,028		—			(b)
Storm reserve(c)	20		22			(b)
Accrued pension and OPEB	44		46			(j)
Deferred fuel and purchased power	46		105		(f)	2018
Other	359		352			(b)
Total regulatory liabilities	6,357		3,001
Less: current portion	126		161
Total noncurrent regulatory liabilities	$	6,231	$	2,840

(a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted.

(b) The expected recovery or refund period varies or has not been determined.

(c) Included in rate base.

(d) Includes regulatory liabilities related to the change in the North Carolina tax rate discussed in Note 22.

(e) Earns a return on outstanding balance in North Carolina.

(f) Pays interest on over-recovered costs in North Carolina. Includes certain purchased power costs in North Carolina and South Carolina and costs of distributed energy in South Carolina.

(g) Recovered over the life of the associated assets.

(h) Includes incentives on DSM/EE investments and is recovered through an annual rider mechanism.

(i) Earns a debt return on coal ash expenditures for North Carolina and South Carolina retail customers.

(j) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 21 for additional detail.

2017 North Carolina Rate Case

On August 25, 2017, Duke Energy Carolinas filed an application with the NCUC for a rate increase for retail customers of approximately $647 million, which represents an approximate 13.6 percent increase in annual base revenues. The rate increase is driven by capital investments subsequent to the previous base rate case, including grid improvement projects, AMI, investments in customer service technologies, costs of complying with coal combustion residuals (CCR) regulations and the North Carolina Coal Ash Management Act of 2014 (Coal Ash Act) and recovery of costs related to licensing and development of the William States Lee III Nuclear Station (Lee Nuclear Station) discussed below. On January 23, 2018, the North Carolina Public Staff filed testimony recommending an overall rate decrease of approximately $290 million. An evidentiary hearing is scheduled to begin on February 27, 2018, and a decision and revised customer rates are expected by mid-2018. Duke Energy Carolinas cannot predict the outcome of this matter.

FERC Formula Rate Matter

On July 31, 2017, Piedmont Municipal Power Agency (PMPA) filed a complaint with FERC against Duke Energy Carolinas alleging that Duke Energy Carolinas misapplied the formula rate under the purchase power agreement (PPA) between the parties by including regulatory amortization in its rates without FERC approval. Duke Energy Carolinas disagreed with PMPA as it believed it was properly applying its FERC filed rate. On February 15, 2018, FERC issued an order ruling in favor of PMPA and ordered Duke Energy Carolinas to refund to PMPA all amounts improperly collected under the PPA. Resolution of this matter is not expected to be material.

Lincoln County Combustion Turbine

On December 7, 2017, the NCUC issued an order approving a Certificate of Public Convenience and Necessity (CPCN) for Duke Energy Carolinas' proposed 402-megawatt (MW) simple cycle, advanced combustion turbine natural gas-fueled electric generating unit at its existing Lincoln County site. The CPCN also includes construction of related transmission and natural gas pipeline interconnection facilities. Construction is scheduled to begin in 2018 with an extended commissioning and validation period from 2020-2024 and an estimated commercial operation date in 2024. As a condition of the approval, Duke Energy Carolinas will not seek recovery of costs associated with the project until it is placed into commercial operation.

Advanced Metering Infrastructure Deferral

On July 12, 2016, the PSCSC issued an accounting order for Duke Energy Carolinas to defer the financial effects of depreciation expense incurred for the installation of AMI meters, the carrying costs on the investment at its weighted average cost of capital (WACC) and the carrying costs on the deferred costs at its WACC not to exceed $45 million. The decision also allows Duke Energy Carolinas to continue to depreciate the non-AMI meters to be replaced. Current retail rates will not change as a result of the decision and the ability of interested parties to challenge the reasonableness of expenditures in subsequent proceedings is not limited.

William States Lee Combined Cycle Facility

On April 9, 2014, the PSCSC granted Duke Energy Carolinas and North Carolina Electric Membership Corporation (NCEMC) a Certificate of Environmental Compatibility and Public Convenience and Necessity (CECPCN) for the construction and operation of a 750-MW combined-cycle natural gas-fired generating plant at Duke Energy Carolinas' existing William States Lee Generating Station in Anderson, South Carolina. Duke Energy Carolinas began construction in July 2015 and estimates a cost to build of $600 million for its share of the facility, including allowance for funds used during construction (AFUDC). The project is expected to be commercially available in the first quarter of 2018. NCEMC will own approximately 13 percent of the project. On July 3, 2014, the South Carolina Coastal Conservation League (SCCL) and Southern Alliance for Clean Energy (SACE) jointly filed a Notice of Appeal with the Court of Appeals of South Carolina (S.C. Court of Appeals) seeking the court's review of the PSCSC's decision, claiming the PSCSC did not properly consider a request related to a proposed solar facility prior to granting approval of the CECPCN. The S.C. Court of Appeals affirmed the PSCSC's decision on February 10, 2016, and on March 24, 2016, denied a request for rehearing filed by SCCL and SACE. On April 21, 2016, SCCL and SACE petitioned the South Carolina Supreme Court for review of the S.C. Court of Appeals decision. On March 24, 2017, the South Carolina Supreme Court denied the request for review, thus concluding the matter.

Lee Nuclear Station

In December 2007, Duke Energy Carolinas applied to the NRC for combined operating licenses (COLs) for two Westinghouse AP1000 reactors for the proposed William States Lee III Nuclear Station to be located at a site in Cherokee County, South Carolina. The NCUC and PSCSC concurred with the prudency of Duke Energy Carolinas incurring certain project development and preconstruction costs through several separately issued orders, although full cost recovery is not guaranteed. In December 2016, the NRC issued a COL for each reactor. Duke Energy Carolinas is not required to build the nuclear reactors as result of the COLs being issued.

On March 29, 2017, Westinghouse filed for voluntary Chapter 11 bankruptcy in the U.S. Bankruptcy Court for the Southern District of New York. As part of its 2017 North Carolina Rate Case discussed above, Duke Energy Carolinas is seeking NCUC approval to cancel the development of the Lee Nuclear Station project due to the Westinghouse bankruptcy filing and other market activity and is requesting recovery of incurred licensing and development costs. Duke Energy Carolinas will maintain the license issued by the NRC in December 2016 as an option for potential future development. As of December 31, 2017, Duke Energy Carolinas has incurred approximately $558 million of costs, including AFUDC, related to the project. These project costs are included in Net property, plant and equipment on Duke Energy Carolinas’ Consolidated Balance Sheets. Duke Energy Carolinas cannot predict the outcome of this matter.

Duke Energy Progress

Regulatory Assets and Liabilities

The following tables present the regulatory assets and liabilities recorded on Duke Energy Progress' Consolidated Balance Sheets.

	December 31,				Earns/Pays	Recovery/Refund
(in millions)	2017		2016		a Return	Period Ends
Regulatory Assets(a)
AROs - coal ash	$	1,975	$	1,822	(i)	(b)
AROs - nuclear and other	359		275			(c)
Accrued pension and OPEB	430		423			(l)
Retired generation facilities	170		165		X	2023
Net regulatory asset related to income taxes	—		7			(d)
Storm cost deferrals(e)	150		148		X	(b)
Hedge costs deferrals	64		66			(b)
DSM/EE(f)	264		263		(j)	2018
Vacation accrual	42		38			2018
Deferred fuel and purchased power	130		24		(g)	2018
Nuclear deferral	35		38			2019
PISCC and deferred operating expenses	38		42		X	2054
AMI	75		—			(b)
NCEMPA deferrals	53		51		(h)	2042
Other	74		69			(b)
Total regulatory assets	3,859		3,431
Less: current portion	352		188
Total noncurrent regulatory assets	$	3,507	$	3,243
Regulatory Liabilities(a)
Costs of removal	$	2,122	$	1,840	X	(k)
Net regulatory liability related to income taxes	1,854		—			(b)
Deferred fuel and purchased power	1		64		(g)	2018
Other	161		200			(b)
Total regulatory liabilities	4,138		2,104
Less: current portion	139		158
Total noncurrent regulatory liabilities	$	3,999	$	1,946

(a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted.

(b) The expected recovery or refund period varies or has not been determined.

(c) Recovery period for costs related to nuclear facilities runs through the decommissioning period of each unit.

(d) Recovery over the life of the associated assets. Includes regulatory liabilities related to the change in the North Carolina tax rate discussed in Note 22.

(e) South Carolina storm costs are included in rate base.

(f) Included in rate base.

(g) Pays interest on over-recovered costs in North Carolina. Includes certain purchased power costs in North Carolina and South Carolina and costs of distributed energy in South Carolina.

(h) South Carolina retail allocated costs are earning a return.

(i) Earns a debt return on coal ash expenditures for North Carolina and South Carolina retail customers.

(j) Includes incentives on DSM/EE investments.

(k) Recovered over the life of the associated assets.

(l) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 21 for additional detail.

2017 North Carolina Rate Case

On June 1, 2017, Duke Energy Progress filed an application with the NCUC for a rate increase for retail customers of approximately $477 million, which represented an approximate 14.9 percent increase in annual base revenues. Subsequent to the filing, Duke Energy Progress adjusted the requested amount to $420 million, representing an approximate 13 percent increase. The rate increase is driven by capital investments subsequent to the previous base rate case, costs of complying with CCR regulations and the Coal Ash Act, costs relating to storm recovery, investments in customer service technologies and recovery of costs associated with renewable purchased power. On November 22, 2017, Duke Energy Progress and the North Carolina Public Staff filed an Agreement and Stipulation of Partial Settlement resolving certain portions of the proceeding, pending NCUC approval. Terms of the settlement include a return on equity of 9.9 percent and a capital structure of 52 percent equity and 48 percent debt. As a result of the settlement, in 2017 Duke Energy Progress recorded pretax charges totaling approximately $25 million to Impairment charges and Operation, maintenance and other on the Consolidated Income Statements, principally related to disallowances from rate base of certain projects at the Mayo and Sutton plants. The settlement does not include agreement on portions of the rate case relating to recovery of deferred storm recovery costs and coal ash basin deferred costs, which will be decided by the NCUC separately. Taking into consideration the settled portions and Duke Energy Progress’ requested recovery of the non-settled portions, the requested rate increase is reduced to approximately $300 million. An evidentiary hearing ended December 7, 2017, and a decision and revised customer rates are expected in the first quarter of 2018. Duke Energy Progress cannot predict the outcome of this matter.

Storm Cost Deferral Filings

On December 16, 2016, Duke Energy Progress filed a petition with the NCUC requesting an accounting order to defer certain costs incurred in connection with response to Hurricane Matthew and other significant storms in 2016. The final estimate of incremental operation and maintenance and capital costs of $116 million was filed with the NCUC in September 2017. On March 15, 2017, the NCUC Public Staff filed comments supporting deferral of a portion of Duke Energy Progress’ requested amount. Duke Energy Progress filed reply comments on April 12, 2017. On July 10, 2017, the NCUC consolidated Duke Energy Progress' storm deferral request into the Duke Energy Progress rate case docket for decision. See "2017 North Carolina Rate Case" for additional discussion. As of December 31, 2017, Duke Energy Progress has approximately $77 million included in Regulatory assets on its Consolidated Balance Sheets. Duke Energy Progress cannot predict the outcome of this matter.

On December 16, 2016, Duke Energy Progress filed a petition with the PSCSC requesting an accounting order to defer certain costs incurred related to repairs and restoration of service following Hurricane Matthew. The final estimate of incremental operation and maintenance and capital costs was approximately $74 million. In January 2017, the PSCSC approved the deferral request and issued an accounting order. As of December 31, 2017, Duke Energy Progress has approximately $73 million included in Regulatory assets on its Consolidated Balance Sheets.

South Carolina Rate Case

In December 2016, the PSCSC approved a rate case settlement agreement among the ORS (Office of Regulatory Staff), intervenors and Duke Energy Progress. Terms of the settlement agreement included an approximate $56 million increase in revenues over a two-year period. An increase of approximately $38 million in revenues was effective January 1, 2017, and an additional increase of approximately $18.5 million in revenues was effective January 1, 2018. Duke Energy Progress amortized approximately $18.5 million from the cost of removal reserve in 2017. Other settlement terms included a rate of return on equity of 10.1 percent, recovery of coal ash costs incurred from January 1, 2015, through June 30, 2016, over a 15‑year period and ongoing deferral of allocated ash basin closure costs from July 1, 2016, until the next base rate case. The settlement also provides that Duke Energy Progress will not seek an increase in rates in South Carolina to occur prior to 2019, with limited exceptions.

Western Carolinas Modernization Plan

On November 4, 2015, Duke Energy Progress announced a Western Carolinas Modernization Plan, which included retirement of the existing Asheville coal-fired plant, the construction of two 280‑MW combined-cycle natural gas plants having dual fuel capability, with the option to build a third natural gas simple cycle unit in 2023 based upon the outcome of initiatives to reduce the region's power demand. The plan also included upgrades to existing transmission lines and substations, installation of solar generation and a pilot battery storage project. These investments will be made within the next seven years. Duke Energy Progress is also working with the local natural gas distribution company to upgrade an existing natural gas pipeline to serve the natural gas plant.

On March 28, 2016, the NCUC issued an order approving a CPCN for the new combined-cycle natural gas plants, but denying the CPCN for the contingent simple cycle unit without prejudice to Duke Energy Progress to refile for approval in the future. On March 28, 2017, Duke Energy Progress filed an annual progress report for the construction of the combined-cycle plants with the NCUC, with an estimated cost of $893 million. Site preparation activities for the combined-cycle plants are underway and construction of these plants began in 2017, with an expected in-service date in late 2019. Duke Energy Progress plans to file for future approvals related to the proposed solar generation and pilot battery storage project.

The carrying value of the 376-MW Asheville coal-fired plant, including associated ash basin closure costs, of $385 million and $492 million are included in Generation facilities to be retired, net on Duke Energy Progress' Consolidated Balance Sheets as of December 31, 2017, and 2016, respectively.

Shearon Harris Nuclear Plant Expansion

In 2006, Duke Energy Progress selected a site at Harris to evaluate for possible future nuclear expansion. On February 19, 2008, Duke Energy Progress filed its COL application with the NRC for two Westinghouse AP1000 reactors at Harris, which the NRC docketed for review. On May 2, 2013, Duke Energy Progress filed a letter with the NRC requesting the NRC to suspend its review activities associated with the COL at the Harris site. The NCUC and PSCSC approved deferral of retail costs. Total deferred costs were approximately $47 million as of December 31, 2017, and are recorded in Regulatory assets on Duke Energy Progress’ Consolidated Balance Sheets. On November 17, 2016, the FERC approved Duke Energy Progress’ rate recovery request filing for the wholesale ratepayers’ share of the abandonment costs, including a debt only return to be recovered through revised formula rates and amortized over a 15-year period beginning May 1, 2014. As part of the settlement agreement for the 2017 North Carolina Rate Case discussed above, Duke Energy Progress will amortize the regulatory asset over an eight-year period. The settlement is subject to NCUC approval. Duke Energy Progress cannot predict the outcome of this matter.

Duke Energy Florida

Regulatory Assets and Liabilities

The following tables present the regulatory assets and liabilities recorded on Duke Energy Florida's Consolidated Balance Sheets.

	December 31,				Earns/Pays	Recovery/Refund
(in millions)	2017		2016		a Return	Period Ends
Regulatory Assets(a)
AROs - coal ash(c)	$	9	$	8	X	(b)
AROs - nuclear and other(c)	296		294		X	(b)
Accrued pension and OPEB(c)	476		458		X	(h)
Retired generation facilities(c)	216		257		X	(b)
Net regulatory asset related to income taxes(c)	—		224		X	(d)
Storm cost deferrals(c)	376		—		(f)	2021
Nuclear asset securitized balance, net	1,142		1,193			2036
Hedge costs deferrals	30		25			2018
DSM/EE(c)	17		15		X	2018
Deferred fuel and purchased power(c)	219		87		(g)	2019
Nuclear deferral	—		96
AMI(c)	75		—		X	2032
Other	36		36			(b)
Total regulatory assets	2,892		2,693
Less: current portion	389		213
Total noncurrent regulatory assets	$	2,503	$	2,480
Regulatory Liabilities(a)
Costs of removal(c)	$	415	$	358	(e)	(b)
Net regulatory liability related to income taxes(c)	948		—			(b)
Storm reserve(c)	—		60
Deferred fuel and purchased power(c)	—		17		(g)
Other	18		44			(b)
Total regulatory liabilities	1,381		479
Less: current portion	74		31
Total noncurrent regulatory liabilities	$	1,307	$	448

(a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted.

(b) The expected recovery or refund period varies or has not been determined.

(c) Included in rate base.

(d) Recovery over the life of the associated assets.

(e) Certain costs earn a return.

(f) Earns a debt return/interest once collections begin.

(g) Earns commercial paper rate.

(h) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 21 for additional detail.

Storm Restoration Cost Recovery

In September 2017, Duke Energy Florida’s service territory suffered significant damage from Hurricane Irma, resulting in approximately 1.3 million customers experiencing outages. In the fourth quarter of 2017, Duke Energy Florida also incurred preparation costs related to Hurricane Nate. On December 28, 2017, Duke Energy Florida filed a petition with the FPSC to recover incremental storm restoration costs for Hurricanes Irma and Nate and to replenish the storm reserve. The estimated recovery amount is approximately $513 million to be recovered over a three-year period beginning in March 2018, subject to true up, which includes reestablishment of a $132 million storm reserve. At December 31, 2017, Duke Energy Florida's Consolidated Balance Sheets included approximately $376 million of recoverable costs under the FPSC's storm rule in Regulatory assets within Other Noncurrent Assets related to storm recovery. On February 6, 2018, the FPSC approved Duke Energy Florida's motion to approve a stipulation that would apply tax savings resulting from the Tax Act toward storm costs in lieu of implementing a storm surcharge.

2017 Second Revised and Restated Settlement Agreement

On November 20, 2017, the FPSC issued an order to approve the 2017 Second Revised and Restated Settlement Agreement (2017 Settlement) filed by Duke Energy Florida. The 2017 Settlement replaces and supplants the 2013 Settlement. The 2017 Settlement extends the base rate case stay-out provision from the 2013 Settlement through the end of 2021 unless actual or projected return on equity falls below 9.5 percent; however, Duke Energy Florida is allowed a multiyear increase to its base rates of $67 million per year in 2019, 2020 and 2021, as well as base rate increases for solar generation. In addition to carrying forward the provisions contained in the 2013 Settlement related to the Crystal River 1 and 2 coal units discussed below and future generation needs in Florida, the 2017 Settlement contains provisions related to future investments in solar and renewable energy technology, future investments in AMI technology as well as recovery of existing meters, impacts of the Tax Act, an electric vehicle charging station pilot program and the termination of the proposed Levy Nuclear Project discussed below. As part of the 2017 Settlement, Duke Energy Florida will not move forward with building the Levy nuclear plant and recorded a pretax impairment charge of approximately $135 million in 2017 to write off all unrecovered Levy Nuclear Project costs, including the COL. As a result of the 2017 Settlement, Duke Energy Florida transferred $75 million to a regulatory asset for the net book value of existing meter technology, which will be recovered over a 15-year period.

The 2017 Settlement includes provisions to recover 2017 under-recovered fuel costs of approximately $196 million over a 24-month period beginning in January 2018. On September 1, 2017, Duke Energy Florida submitted Alternate 2018 Fuel and Capacity clause projection filings consistent with the terms of the 2017 Settlement. The updated capacity filing reflects the removal of all Levy costs. The FPSC approved Duke Energy Florida's 2018 Alternate projection filings on October 25, 2017.

Hines Chiller Uprate Project

On February 2, 2017, Duke Energy Florida filed a petition seeking approval to include in base rates the revenue requirement for a Chiller Uprate Project (Uprate Project) at the Hines Energy Complex. The Uprate Project was placed into service in March 2017 at a cost of approximately $150 million. The annual retail revenue requirement is approximately $19 million. On March 28, 2017, the FPSC issued an order approving the revenue requirement, which was included in base rates for the first billing cycle of April 2017.

Citrus County Combined Cycle Facility

On October 2, 2014, the FPSC granted Duke Energy Florida a Determination of Need for the construction of a 1,640-MW combined-cycle natural gas plant in Citrus County, Florida. On May 5, 2015, the Florida Department of Environmental Protection approved Duke Energy Florida's Site Certification Application. The project has received all required permits and approvals and construction began in October 2015. The facility is expected to be commercially available in 2018 at an estimated cost of $1.5 billion, including AFUDC. The plant will receive natural gas from the Sabal Trail Transmission, LLC (Sabal Trail) pipeline discussed below.

Purchase of Osprey Energy Center

Duke Energy Florida received a Civil Investigative Demand from the Department of Justice (DOJ) related to alleged violation of the waiting period for the Hart-Scott-Rodino Antitrust Improvements Act of 1976 related to the purchase of the Osprey Energy Center, LLC, which was completed in January 2017. The DOJ alleged Duke Energy Florida assumed operational control of the Osprey Plant before the waiting period expiration on February 27, 2015. On January 17, 2017, Duke Energy Florida entered into a stipulation agreement to settle with the DOJ for $600,000 without admission of liability. On January 18, 2017, the DOJ filed a complaint and the stipulation in the U.S. District Court for the District of Columbia, which was approved by the court. A final order dismissing the case was entered in April 2017.

Crystal River Unit 3

In December 2014, the FPSC approved Duke Energy Florida's decision to construct an independent spent fuel storage installation (ISFSI) for the retired Crystal River Unit 3 nuclear plant and approved Duke Energy Florida's request to defer amortization of the ISFSI pending resolution of litigation against the federal government as a result of the Department of Energy's breach of its obligation to accept spent nuclear fuel. The return rate is based on the currently approved AFUDC rate with a return on equity of 7.35 percent, or 70 percent of the currently approved 10.5 percent. The return rate is subject to change if the return on equity changes in the future. In September 2016, the FPSC approved an amendment to the 2013 Settlement authorizing recovery of the ISFSI through the Capacity Cost Recovery Clause. Through December 31, 2017, Duke Energy Florida has deferred approximately $113 million for recovery associated with building the ISFSI. See Note 5 for additional information on spent nuclear fuel litigation.

The regulatory asset associated with the original Crystal River Unit 3 power uprate project will continue to be recovered through the NCRC over an estimated seven-year period that began in 2013 with a remaining uncollected balance of $87 million at December 31, 2017.

Crystal River Unit 3 Regulatory Asset

On September 15, 2015, the FPSC approved Duke Energy Florida's motion for approval of a settlement agreement with intervenors to reduce the value of the projected Crystal River Unit 3 regulatory asset to be recovered to $1.283 billion as of December 31, 2015. An impairment charge of $15 million was recognized in 2015 to adjust the regulatory asset balance. In November 2015, the FPSC issued a financing order approving Duke Energy Florida’s request to issue nuclear asset-recovery bonds to finance its unrecovered regulatory asset related to Crystal River Unit 3 through a wholly owned special purpose entity. Nuclear asset-recovery bonds replace the base rate recovery methodology authorized by the 2013 Settlement and result in a lower rate impact to customers with a recovery period of approximately 20 years.

Pursuant to provisions in Florida Statutes and the FPSC financing order, in 2016, Duke Energy Florida formed Duke Energy Florida Project Finance, LLC (DEFPF), a wholly owned, bankruptcy remote special purpose subsidiary for the purpose of issuing nuclear asset-recovery bonds. In June 2016, DEFPF issued $1,294 million aggregate principal amount of senior secured bonds (nuclear asset-recovery bonds) to finance the recovery of Duke Energy Florida's Crystal River 3 regulatory asset.

In connection with this financing, net proceeds to DEFPF of approximately $1,287 million, after underwriting costs, were used to acquire nuclear asset-recovery property from Duke Energy Florida and to pay transaction related expenses. The nuclear asset-recovery property includes the right to impose, bill, collect and adjust a non-bypassable nuclear asset-recovery charge, to be collected on a per kilowatt-hour basis, from all Duke Energy Florida retail customers until the bonds are paid in full. Duke Energy Florida began collecting the nuclear asset-recovery charge on behalf of DEFPF in customer rates in July 2016.

See Note 17 for additional information.

Levy Nuclear Project

On July 28, 2008, Duke Energy Florida applied to the NRC for COLs for two Westinghouse AP1000 reactors at Levy (Levy Nuclear Project). In 2008, the FPSC granted Duke Energy Florida’s petition for an affirmative Determination of Need and related orders requesting cost recovery under Florida’s nuclear cost-recovery rule, together with the associated facilities, including transmission lines and substation facilities. In October 2016, the NRC issued COLs for the proposed Levy Nuclear Plant Units 1 and 2. Duke Energy Florida is not required to build the nuclear reactors as a result of the COLs being issued.

On January 28, 2014, Duke Energy Florida terminated the Levy engineering, procurement and construction agreement (EPC). Duke Energy Florida may be required to pay for work performed under the EPC. Duke Energy Florida recorded an exit obligation in 2014 for the termination of the EPC. This liability was recorded within Other in Other Noncurrent Liabilities with an offset primarily to Regulatory assets on the Consolidated Balance Sheets. Duke Energy Florida is allowed to recover reasonable and prudent EPC cancellation costs from its retail customers. On May 1, 2017, Duke Energy Florida filed a request with the FPSC to recover approximately $82 million of Levy Nuclear Project costs from retail customers in 2018. As part of the 2017 Settlement discussed above, Duke Energy Florida is no longer seeking recovery of costs related to the Levy Nuclear Project and the ongoing Westinghouse litigation discussed in Note 5. All remaining Levy Nuclear Project issues have been resolved.

Crystal River 1 and 2 Coal Units

Duke Energy Florida has evaluated Crystal River 1 and 2 coal units for retirement in order to comply with certain environmental regulations. Based on this evaluation, those units are expected to be retired by the end of 2018. Once those units are retired Duke Energy Florida will continue recovery of existing annual depreciation expense through the end of 2020. Beginning in 2021, Duke Energy Florida will be allowed to recover any remaining net book value of the assets from retail customers through the Capacity Cost Recovery Clause.

Duke Energy Ohio

Regulatory Assets and Liabilities

The following tables present the regulatory assets and liabilities recorded on Duke Energy Ohio's Consolidated Balance Sheets.

	December 31,				Earns/Pays	Recovery/Refund
(in millions)	2017		2016		a Return	Period Ends
Regulatory Assets(a)
AROs - coal ash	$	17	$	12	X	(b)
Accrued pension and OPEB	139		135			(g)
Net regulatory asset related to income taxes(c)	—		63			(d)
Storm cost deferrals	5		5			(b)
Hedge costs deferrals	6		7			(b)
DSM/EE	18		6		(f)	(e)
Grid modernization	39		65		X	(e)
Vacation accrual	5		4			2018
Deferred fuel and purchased power	—		5
PISCC and deferred operating expenses(c)	19		20		X	2083
Transmission expansion obligation	50		71			(e)
MGP	91		99			(b)
AMI	6		—			(b)
East Bend deferrals	45		32		X	(b)
Deferred pipeline integrity costs	12		7		X	(b)
Other	42		26			(b)
Total regulatory assets	494		557
Less: current portion	49		37
Total noncurrent regulatory assets	$	445	$	520
Regulatory Liabilities(a)
Costs of removal	$	189	$	212		(d)
Net regulatory liability related to income taxes	688		—			(b)
Accrued pension and OPEB	16		19			(g)
Deferred fuel and purchased power	—		6
Other	34		20			(b)
Total regulatory liabilities	927		257
Less: current portion	36		21
Total noncurrent regulatory liabilities	$	891	$	236

(a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted.

(b) The expected recovery or refund period varies or has not been determined.

(c) Included in rate base.

(d) Recovery over the life of the associated assets.

(e) Recovered via a rider mechanism.

(f) Includes incentives on DSM/EE investments.

(g) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 21 for additional detail.

Duke Energy Kentucky Rate Case

On September 1, 2017, Duke Energy Kentucky filed a rate case with the KPSC requesting an increase in electric base rates of approximately $49 million, which represents an approximate 15 percent increase on the average customer bill. The rate increase is driven by increased investment in utility plant, increased operations and maintenance expenses and recovery of regulatory assets. The application also includes implementation of the Environmental Surcharge Mechanism to recover environmental costs not included in base rates, requests to establish a Distribution Capital Investment Rider to recover incremental costs of specific programs, requests to establish a FERC Transmission Cost Reconciliation Rider to recover escalating transmission costs and modification to the Profit Sharing Mechanism to increase customers' share of proceeds from the benefits of owning generation and to mitigate shareholder risks associated with that generation. An evidentiary hearing is scheduled to begin on March 6, 2018.Duke Energy Kentucky anticipates that rates will go into effect in mid-April 2018. Duke Energy Kentucky cannot predict the outcome of this matter.

2017 Electric Security Plan

On June 1, 2017, Duke Energy Ohio filed with the PUCO a request for a standard service offer in the form of an electric security plan (ESP). If approved by the PUCO, the term of the ESP would be from June 1, 2018, to May 31, 2024. Terms of the ESP include continuation of market-based customer rates through competitive procurement processes for generation, continuation and expansion of existing rider mechanisms and proposed new rider mechanisms relating to regulatory mandates, costs incurred to enhance the customer experience and transform the grid and a service reliability rider for vegetation management. On February 15, 2018, the procedural schedule was suspended to facilitate ongoing settlement discussions. Duke Energy Ohio cannot predict the outcome of this matter.

Woodsdale Station Fuel System Filing

On June 9, 2015, the FERC ruled in favor of PJM Interconnection, LLC (PJM) on a revised Tariff and Reliability Assurance Agreement including implementation of a Capacity Performance (CP) proposal and to amend sections of the Operating Agreement related to generation non-performance. The CP proposal includes performance-based penalties for non-compliance. Duke Energy Kentucky is a Fixed Resource Requirement (FRR) entity, and therefore is subject to the compliance standards through its FRR plans. A partial CP obligation will apply to Duke Energy Kentucky in the delivery year beginning June 1, 2019, with full compliance beginning June 1, 2020. Duke Energy Kentucky has developed strategies for CP compliance investments. On December 21, 2017, the KPSC issued an order approving Duke Energy Kentucky's request for a CPCN to construct an ultra-low sulfur diesel backup fuel system for the Woodsdale Station. The backup fuel system is projected to cost approximately $55 million and is anticipated to be in service prior to the CP compliance deadline of April 2019.

Ohio Valley Electric Corporation

On March 31, 2017, Duke Energy Ohio filed for approval to adjust its existing price stabilization rider (Rider PSR), which is currently set at zero dollars, to pass through net costs related to its contractual entitlement to capacity and energy from the generating assets owned by OVEC. The filing seeks to adjust Rider PSR for OVEC costs subsequent to April 1, 2017. Duke Energy Ohio is seeking deferral authority for net costs incurred from April 1, 2017, until the new rates under Rider PSR are put into effect. Various intervenors have filed motions to dismiss or stay the proceeding and Duke Energy Ohio has opposed these filings. See Note 13 for additional discussion of Duke Energy Ohio's ownership interest in OVEC. Duke Energy Ohio cannot predict the outcome of this matter.

East Bend Coal Ash Basin Filing

On December 2, 2016, Duke Energy Kentucky filed with the KPSC a request for a CPCN for construction projects necessary to close and repurpose an ash basin at the East Bend facility as a result of current and proposed EPA regulations. Duke Energy Kentucky estimated a total cost of approximately $93 million in the filing and expects in-service date by the first quarter of 2021. On June 6, 2017, the KPSC approved the CPCN request.

Electric Base Rate Case

Duke Energy Ohio filed with the PUCO an electric distribution base rate case application and supporting testimony in March 2017. Duke Energy Ohio requested an estimated annual increase of approximately $15 million and a return on equity of 10.4 percent. The application also includes requests to continue certain current riders and establish new riders. On September 26, 2017, the PUCO staff filed a report recommending a revenue decrease between approximately $18 million and $29 million and a return on equity between 9.22 percent and 10.24 percent. On February 15, 2018, the procedural schedule was suspended to facilitate ongoing settlement discussions. Duke Energy Ohio expects rates will go into effect the second quarter of 2018. Duke Energy Ohio cannot predict the outcome of this matter.

Natural Gas Pipeline Extension

Duke Energy Ohio is proposing to install a new natural gas pipeline in its Ohio service territory to increase system reliability and enable the retirement of older infrastructure. On January 20, 2017, Duke Energy Ohio filed an amended application with the Ohio Power Siting Board for approval of one of two proposed routes. A public hearing was held on June 15, 2017, and an adjudicatory hearing was scheduled to begin September 11, 2017. On August 24, 2017, an administrative law judge (ALJ) granted a request made by Duke Energy Ohio to delay the procedural schedule while it works through various issues related to the pipeline route. If approved, construction of the pipeline extension is expected to be completed before the 2020/2021 winter season. The proposed project involves the installation of a natural gas line and is estimated to cost approximately $110 million, excluding AFUDC.

Advanced Metering Infrastructure

On April 25, 2016, Duke Energy Kentucky filed with the KPSC an application for approval of a CPCN for the construction of advanced metering infrastructure. Duke Energy Kentucky estimates the $49 million project will take two years to complete. Duke Energy Kentucky also requested approval to establish a regulatory asset for the remaining book value of existing meter equipment and inventory to be replaced. Duke Energy Kentucky and the Kentucky attorney general entered into a stipulation to settle matters related to the application. On May 25, 2017, the KPSC issued an order to approve the stipulation with certain modifications. On June 1, 2017, Duke Energy Kentucky filed its acceptance of the modifications. The deployment of AMI meters began in third quarter 2017 and is expected to be completed in early 2019. Duke Energy Ohio has approximately $6 million included in Regulatory assets on its Consolidated Balance Sheets at December 31, 2017, for the book value of existing meter equipment.

Accelerated Natural Gas Service Line Replacement Rider

On January 20, 2015, Duke Energy Ohio filed an application for approval of an accelerated natural gas service line replacement program (ASRP). Under the ASRP, Duke Energy Ohio proposed to replace certain natural gas service lines on an accelerated basis over a 10-year period. Duke Energy Ohio also proposed to complete preliminary survey and investigation work related to natural gas service lines that are customer owned and for which it does not have valid records and, further, to relocate interior natural gas meters to suitable exterior locations where such relocation can be accomplished. Duke Energy Ohio's projected total capital and operations and maintenance expenditures under the ASRP were approximately $240 million. The filing also sought approval of a rider mechanism (Rider ASRP) to recover related expenditures. Duke Energy Ohio proposed to update Rider ASRP on an annual basis. Intervenors opposed the ASRP, primarily because they believe the program is neither required nor necessary under federal pipeline regulation. On October 26, 2016, the PUCO issued an order denying the proposed ASRP. Duke Energy Ohio's application for rehearing of the PUCO decision was denied on May 17, 2017.

Energy Efficiency Cost Recovery

On March 28, 2014, Duke Energy Ohio filed an application for recovery of program costs, lost distribution revenue and performance incentives related to its energy efficiency and peak demand reduction programs. These programs are undertaken to comply with environmental mandates set forth in Ohio law. The PUCO approved Duke Energy Ohio’s application but found that Duke Energy Ohio was not permitted to use banked energy savings from previous years in order to calculate the amount of allowed incentive. This conclusion represented a change to the cost recovery mechanism that had been agreed upon by intervenors and approved by the PUCO in previous cases. The PUCO granted the applications for rehearing filed by Duke Energy Ohio and an intervenor. On January 6, 2016, Duke Energy Ohio and the PUCO Staff entered into a stipulation, pending the PUCO's approval, to resolve issues related to performance incentives and the PUCO Staff audit of 2013 costs, among other issues. In December 2015, based upon the stipulation, Duke Energy Ohio re-established approximately $20 million of the revenues that had been previously reversed. On October 26, 2016, the PUCO issued an order approving the stipulation without modification. In December 2016, the PUCO granted the intervenors request for rehearing for the purpose of further review. Duke Energy Ohio cannot predict the outcome of this matter.

On June 15, 2016, Duke Energy Ohio filed an application for approval of a three-year energy efficiency and peak demand reduction portfolio of programs. A stipulation and modified stipulation were filed on December 22, 2016, and January 27, 2017, respectively. Under the terms of the stipulations, which included support for deferral authority of all costs and a cap on shared savings incentives, Duke Energy Ohio offered its energy efficiency and peak demand reduction programs throughout 2017. On February 3, 2017, Duke Energy Ohio filed for deferral authority of its costs incurred in 2017 in respect of its proposed energy efficiency and peak demand reduction portfolio. On September 27, 2017, the PUCO issued an order approving a modified stipulation. The modifications impose an annual cap of approximately $38 million on program costs and shared savings incentives combined, but allowed for Duke Energy Ohio to file for a waiver of costs in excess of the cap in 2017. The PUCO approved the waiver request up to a total cost of $56 million. On November 21, 2017, the PUCO granted Duke Energy Ohio's and intervenor's applications for rehearing of the September 27, 2017, order. On January 10, 2018, the PUCO denied the Ohio Consumers' Counsel’s application for rehearing of the PUCO order granting Duke Energy Ohio's waiver request. Duke Energy Ohio cannot predict the outcome of this matter.

2014 Electric Security Plan

In April 2015, the PUCO modified and approved Duke Energy Ohio's proposed electric security plan (ESP), with a three-year term and an effective date of June 1, 2015. The PUCO approved a competitive procurement process for SSO load, a distribution capital investment rider and a tracking mechanism for incremental distribution expenses caused by major storms. The PUCO also approved a placeholder tariff for a price stabilization rider, but denied Duke Energy Ohio's specific request to include Duke Energy Ohio's entitlement to generation from OVEC in the rider at this time; however, the order allows Duke Energy Ohio to submit additional information to request recovery in the future. On May 4, 2015, Duke Energy Ohio filed an application for rehearing requesting the PUCO to modify or amend certain aspects of the order. On May 28, 2015, the PUCO granted all applications for rehearing filed in the case for future consideration. Duke Energy Ohio cannot predict the outcome of the appeals in this matter.

2012 Natural Gas Rate Case/MGP Cost Recovery

On November 13, 2013, the PUCO issued an order approving a settlement of Duke Energy Ohio’s natural gas base rate case and authorizing the recovery of costs incurred between 2008 and 2012 for environmental investigation and remediation of two former MGP sites. The PUCO order also authorized Duke Energy Ohio to continue deferring MGP environmental investigation and remediation costs incurred subsequent to 2012 and to submit annual filings to adjust the MGP rider for future costs. Intervening parties appealed this decision to the Ohio Supreme Court and on June 29, 2017, the Ohio Supreme Court issued its decision affirming the PUCO order. Appellants filed a request for reconsideration, which was denied on September 27, 2017. This matter is now final.

The PUCO order also contained deadlines for completing the MGP environmental investigation and remediation costs at the MGP sites. For the property known as the East End site, the PUCO order established a deadline of December 31, 2016, which was subsequently extended to December 31, 2019. In January 2017, intervening parties filed for rehearing of the PUCO's decision. On February 8, 2017, the PUCO denied the rehearing request. As of December 31, 2017, Duke Energy Ohio had approximately, $35 million included in Regulatory assets on the Consolidated Balance Sheets for future remediation costs expected to be incurred at the East End site.

Regional Transmission Organization Realignment

Duke Energy Ohio, including Duke Energy Kentucky, transferred control of its transmission assets from MISO to PJM Interconnection, LLC (PJM), effective December 31, 2011. The PUCO approved a settlement related to Duke Energy Ohio’s recovery of certain costs of the Regional Transmission Organization (RTO) realignment via a non-bypassable rider. Duke Energy Ohio is allowed to recover all MISO Transmission Expansion Planning (MTEP) costs, including but not limited to Multi Value Project (MVP) costs, directly or indirectly charged to Ohio customers. Duke Energy Ohio also agreed to vigorously defend against any charges for MVP projects from MISO. The KPSC also approved a request to effect the RTO realignment, subject to a commitment not to seek double recovery in a future rate case of the transmission expansion fees that may be charged by MISO and PJM in the same period or overlapping periods.

The following table provides a reconciliation of the beginning and ending balance of Duke Energy Ohio’s recorded liability for its exit obligation and share of MTEP costs, excluding MVP, recorded within Other in Current liabilities and Other in Other Noncurrent Liabilities on the Consolidated Balance Sheets. The retail portions of MTEP costs billed by MISO are recovered by Duke Energy Ohio through a non-bypassable rider. As of December 31, 2017, and 2016, $50 million and $71 million are recorded in Regulatory assets on Duke Energy Ohio's Consolidated Balance Sheets, respectively.

			Provisions/			Cash
(in millions)	December 31, 2016		Adjustments			Reductions			December 31, 2017
Duke Energy Ohio	$	90	$	(20	)	$	(4	)	$	66

MVP. MISO approved 17 MVP proposals prior to Duke Energy Ohio’s exit from MISO on December 31, 2011. Construction of these projects is expected to continue through 2020. Costs of these projects, including operating and maintenance costs, property and income taxes, depreciation and an allowed return, are allocated and billed to MISO transmission owners.

On December 29, 2011, MISO filed a tariff with the FERC providing for the allocation of MVP costs to a withdrawing owner based on monthly energy usage. The FERC set for hearing (i) whether MISO’s proposed cost allocation methodology to transmission owners who withdrew from MISO prior to January 1, 2012, is consistent with the tariff at the time of their withdrawal from MISO and, (ii) if not, what the amount of and methodology for calculating any MVP cost responsibility should be. In 2012, MISO estimated Duke Energy Ohio’s MVP obligation over the period from 2012 to 2071 at $2.7 billion, on an undiscounted basis. On July 16, 2013, a FERC Administrative Law Judge (ALJ) issued an initial decision. Under this initial decision, Duke Energy Ohio would be liable for MVP costs. Duke Energy Ohio filed exceptions to the initial decision, requesting FERC to overturn the ALJ’s decision.

On October 29, 2015, the FERC issued an order reversing the ALJ's decision. The FERC ruled the cost allocation methodology is not consistent with the MISO tariff and that Duke Energy Ohio has no liability for MVP costs after its withdrawal from MISO. On May 19, 2016, the FERC denied the request for rehearing filed by MISO and the MISO Transmission Owners. On July 15, 2016, the MISO Transmission Owners filed a petition for review with the U.S. Court of Appeals for the Sixth Circuit. On June 21, 2017, a three-judge panel affirmed FERC's 2015 decision holding that Duke Energy Ohio has no liability for the cost of the MVP projects constructed after Duke Energy Ohio's withdrawal from MISO. MISO did not file further petitions for review and this matter is now final.

Duke Energy Indiana

Regulatory Assets and Liabilities

The following tables present the regulatory assets and liabilities recorded on Duke Energy Indiana's Consolidated Balance Sheets.

	December 31,				Earns/Pays	Recovery/Refund
(in millions)	2017		2016		a Return	Period Ends
Regulatory Assets(a)
AROs - coal ash	$	380	$	276		(b)
Accrued pension and OPEB	197		222			(g)
Retired generation facilities(c)	65		73		X	2025
Net regulatory asset related to income taxes	—		119			(d)
Hedge costs deferrals	25		26			(b)
DSM/EE	21		—		(e)	(e)
Vacation accrual	11		10			2018
Deferred fuel and purchased power	18		40			2018
PISCC and deferred operating expenses(c)	274		281		X	(b)
Gasification services agreement buyout(f)	—		8
AMI(c)	21		46		X	(b)
Other	131		121			(b)
Total regulatory assets	1,143		1,222
Less: current portion	165		149
Total noncurrent regulatory assets	$	978	$	1,073
Regulatory Liabilities(a)
Costs of removal	$	644	$	660		(d)
Net regulatory liability related to income taxes	998		—			(b)
Amounts to be refunded to customers	10		45			2018
Accrued pension and OPEB	64		72			(g)
Other	31		11			(b)
Total regulatory liabilities	1,747		788
Less: current portion	24		40
Total noncurrent regulatory liabilities	$	1,723	$	748

(a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted.

(b) The expected recovery or refund period varies or has not been determined.

(c) Included in rate base.

(d) Recovery over the life of the associated assets.

(e) Includes incentives on DSM/EE investments and is recovered through a tracker mechanism over a two-year period.

(f) The IURC authorized Duke Energy Indiana to recover costs incurred to buy out a gasification services agreement, including carrying costs through 2017.

(g) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 21 for additional detail.

Coal Combustion Residual Plan

On March 17, 2016, Duke Energy Indiana filed with the IURC a request for approval of its first group of federally mandated CCR rule compliance projects (Phase I CCR Compliance Projects) to comply with the EPA's CCR rule. The projects in this Phase I filing are CCR compliance projects, including the conversion of Cayuga and Gibson stations to dry bottom ash handling and related water treatment. Duke Energy Indiana requested timely recovery of approximately $380 million in retail capital costs, including AFUDC, and recovery of incremental operating and maintenance costs under a federal mandate tracker that provides for timely recovery of 80 percent of such costs and deferral with carrying costs of 20 percent of such costs for recovery in a subsequent retail base rate case. On January 24, 2017, Duke Energy Indiana and various intervenors filed a settlement agreement with the IURC. Terms of the settlement include recovery of 60 percent of the estimated CCR compliance construction project capital costs through existing rider mechanisms and deferral of 40 percent of these costs until Duke Energy Indiana's next general retail rate case. The deferred costs will earn a return based on Duke Energy Indiana's long-term debt rate of 4.73 percent until costs are included in retail rates, at which time the deferred costs will earn a full return. Costs are to be capped at $365 million, plus actual AFUDC. Costs above the cap would be considered for recovery in the next rate case. Terms of the settlement agreement also require Duke Energy Indiana to perform certain reporting and groundwater monitoring. On May 24, 2017, the IURC approved the settlement agreement.

Edwardsport Integrated Gasification Combined Cycle Plant

Costs for the Edwardsport Integrated Gasification Combined Cycle (IGCC) Plant are recovered from retail electric customers via a tracking mechanism (IGCC rider) with updates filed by Duke Energy Indiana. The IGCC Plant was placed into commercial operation in June 2013.

On August 24, 2016, the IURC approved a settlement (IGCC Settlement) among Duke Energy Indiana and several intervenors to resolve disputes related to five IGCC riders (the 11th through 15th) and a subdocket to Duke Energy Indiana's fuel adjustment clause. The IGCC settlement resulted in customers not being billed for previously incurred plant operating costs of $87.5 million and payments and commitments from Duke Energy Indiana of $5.5 million for attorneys’ fees and consumer programs funding. Duke Energy Indiana recognized pretax impairment and related charges of $93 million in 2015. Additionally, under the IGCC settlement, the recovery of operating and maintenance expenses and ongoing maintenance capital at the plant were subject to certain caps during the years of 2016 and 2017. The IGCC settlement also included a commitment to either retire or stop burning coal by December 31, 2022, at the Gallagher Station. Pursuant to the IGCC settlement, the in-service date used for accounting and ratemaking will remain as June 2013. Remaining deferred costs will be recovered over eight years beginning in 2016 and not earn a carrying cost. As of December 31, 2017, deferred costs related to the project are approximately $152 million and are included in Regulatory assets in Current Assets and Other Noncurrent Assets on Duke Energy Indiana's Consolidated Balance Sheets. Under the IGCC settlement, future IGCC riders will be filed annually with the next filing scheduled for first quarter 2018.

The ninth semi-annual IGCC rider order was appealed by various intervenors and the matter was remanded to the IURC for further proceedings and additional findings on a tax in-service issue. On February 2, 2017, the IURC issued an order upholding the original decision, finding that an estimate of impact on customer rates due to the federal income tax in-service determination was reasonable.

FERC Transmission Return on Equity Complaint

Customer groups have filed with the FERC complaints against MISO and its transmission-owning members, including Duke Energy Indiana, alleging, among other things, that the current base rate of return on equity earned by MISO transmission owners of 12.38 percent is unjust and unreasonable. The complaints claim, among other things, that the current base rate of return on equity earned by MISO transmission owners should be reduced to 8.67 percent. On January 5, 2015, the FERC issued an order accepting the MISO transmission owners' adder of 0.50 percent to the base rate of return on equity based on participation in an RTO subject to it being applied to a return on equity that is shown to be just and reasonable in the pending return on equity complaints. On December 22, 2015, the presiding FERC ALJ in the first complaint issued an Initial Decision in which the base rate of return on equity was set at 10.32 percent. On September 28, 2016, the Initial Decision in the first complaint was affirmed by FERC, but is subject to rehearing requests. On June 30, 2016, the presiding FERC ALJ in the second complaint issued an Initial Decision setting the base rate of return on equity at 9.70 percent. The Initial Decision in the second complaint is pending FERC review. On April 14, 2017, the U.S. Court of Appeals for the District of Columbia Circuit, in Emera Maine v. FERC, reversed and remanded certain aspects of the methodology employed by FERC to establish rates of return on equity. This decision may affect the outcome of the complaints against Duke Energy Indiana. Duke Energy Indiana currently believes these matters will not have a material impact on its results of operations, cash flows and financial position.

Grid Infrastructure Improvement Plan

On December 7, 2015, Duke Energy Indiana filed a grid infrastructure improvement plan with an estimated cost of $1.8 billion in response to guidance from IURC orders and the Indiana Court of Appeals decisions related to a new statute. The plan uses a combination of advanced technology and infrastructure upgrades to improve service to customers and provide them with better information about their energy use. It also provides for cost recovery through a transmission and distribution rider (T&D Rider). In March 2016, Duke Energy Indiana entered into a settlement with all parties to the proceeding except the Citizens Action Coalition of Indiana, Inc. The settlement agreement decreased the capital expenditures eligible for timely recovery of costs in the seven-year plan to approximately $1.4 billion, including the removal of an AMI project. Under the settlement, the return on equity to be used in the T&D Rider is 10 percent. The IURC approved the settlement and issued a final order on June 29, 2016. The order was not appealed and the proceeding is concluded.

The settlement agreement provided for deferral accounting for depreciation and post-in-service carrying costs for AMI projects outside the plan. Duke Energy Indiana withdrew its request for a regulatory asset for current meters and will retain any savings associated with future AMI installation until the next retail base rate case, which is required to be filed prior to the end of the plan. During the third quarter of 2016, Duke Energy Indiana decided to implement the AMI project. This decision resulted in a pretax impairment charge related to existing or non-AMI meters of approximately $8 million in 2016, based in part on the requirement to file a base rate case in 2022 under the approved plan. Duke Energy Indiana evaluates the need for rate cases as part of its business planning, based on the outlook of emerging costs, ongoing investment and impact related to the Tax Act enacted in late 2017 and expects to file a rate case prior to the 2022 requirement. As a result, in 2017, Duke Energy Indiana recorded an additional impairment charge of approximately $22 million. As of December 31, 2017, Duke Energy Indiana's remaining net book value of non-AMI meters is approximately $21 million and will be depreciated through July 2020.

Benton County Wind Farm Dispute

On December 16, 2013, Benton County Wind Farm LLC (BCWF) filed a lawsuit against Duke Energy Indiana seeking damages for past generation losses alleging Duke Energy Indiana violated its obligations under a 2006 PPA by refusing to offer electricity to the market at negative prices. Damage claims continue to increase during times that BCWF is not dispatched. Under 2013 revised MISO market rules, Duke Energy Indiana is required to make a price offer to MISO for the power it proposes to sell into MISO markets and MISO determines whether BCWF is dispatched. Because market prices would have been negative due to increased market participation, Duke Energy Indiana determined it would not bid at negative prices in order to balance customer needs against BCWF's need to run. BCWF contends Duke Energy Indiana must bid at the lowest negative price to ensure dispatch, while Duke Energy Indiana contends it is not obligated to bid at any particular price, that it cannot ensure dispatch with any bid and that it has reasonably balanced the parties' interests. On July 6, 2015, the U.S. District Court for the Southern District of Indiana entered judgment against BCWF on all claims. BCWF appealed the decision and on December 9, 2016, the appeals court ruled in favor of BCWF. Duke Energy Indiana recorded an obligation and a regulatory asset related to the settlement amount in fourth quarter 2016. On June 30, 2017, the parties finalized a settlement agreement. Terms of the settlement included Duke Energy Indiana paying $29 million for back damages. Additionally, the parties agreed on the method by which the contract will be bid into the market in the future. The settlement amount was paid in June 2017. The IURC issued an order on September 27, 2017, approving recovery of the settlement amount through Duke Energy Indiana's fuel clause. The IURC order has been appealed to the Indiana Court of Appeals. Duke Energy Indiana cannot predict the outcome of this matter.

Piedmont

Regulatory Assets and Liabilities

The following tables present the regulatory assets and liabilities recorded on Piedmont's Consolidated Balance Sheets.

	December 31,				Earns/Pays	Recovery/Refund
(in millions)	2017		2016		a Return	Period Ends
Regulatory Assets(a)
AROs - other	$	15	$	14		(d)
Accrued pension and OPEB(c)	91		166			(f)
Derivatives - gas supply contracts	142		187			(e)
Vacation accrual(c)	10		13			2018
Deferred pipeline integrity costs(c)	42		36			2018
Amount due from customers	64		66		X	(b)
Other	14		15			(b)
Total regulatory assets	378		497
Less: current portion	95		124
Total noncurrent regulatory assets	$	283	$	373
Regulatory Liabilities(a)
Costs of removal	$	544	$	528		(d)
Net regulatory liability related to income taxes	597		80			(b)
Other	3		—			(b)
Total regulatory liabilities	1,144		608
Less: current portion	3		—
Total noncurrent regulatory liabilities	$	1,141	$	608

(a) Regulatory assets and liabilities are excluded from rate base unless otherwise noted.

(b) The expected recovery or refund period varies or has not been determined.

(c) Included in rate base.

(d) Recovery over the life of the associated assets.

(e) Balance will fluctuate with changes in the market. Current contracts extend into 2031.

(f) Recovered primarily over the average remaining service periods or life expectancies of employees covered by the benefit plans. See Note 21 for additional detail.

South Carolina Rate Stabilization Adjustment Filing

In June 2017, Piedmont filed with the PSCSC under the South Carolina Rate Stabilization Act its quarterly monitoring report for the 12-month period ending March 31, 2017. The filing included a revenue deficiency calculation and tariff rates in order to permit Piedmont the opportunity to earn the rate of return on equity of 12.6 percent established in its last general rate case. On October 4, 2017, the PSCSC approved a settlement agreement between Piedmont and the SC Office of Regulatory Staff. Terms of the settlement included implementation of rates for the 12-month period beginning November 2017 with a return on equity of 10.2 percent.

North Carolina Integrity Management Rider Filings

In October 2017, Piedmont filed a petition with the NCUC under the Integrity Management Rider (IMR) mechanism to collect an additional $8.9 million in annual revenues, effective December 2017, based on the eligible capital investments closed to integrity and safety projects over the six-month period ending September 30, 2017. On November 28, 2017, the NCUC approved the requested rate adjustment.

In May 2017, Piedmont filed, and the NCUC approved, a petition under the IMR mechanism to collect an additional $11.6 million in annual revenues, effective June 2017, based on the eligible capital investments closed to integrity and safety projects over the six-month period ending March 31, 2017.

Tennessee Integrity Management Rider Filing

In November 2017, Piedmont filed a petition with the TPUC under the IMR mechanism to collect an additional $3.3 million in annual revenues, effective January 2018, based on the eligible capital investments closed to integrity and safety projects over the 12-month period ending October 31, 2017. In January 2018, Piedmont filed an amended computation under the IMR mechanism, revising the proposed increase in annual revenues to approximately $0.4 million based on the decrease in the corporate federal income tax rate effective January 1, 2018. A hearing on this matter is scheduled for March 2018.

OTHER REGULATORY MATTERS

Atlantic Coast Pipeline

On September 2, 2014, Duke Energy, Dominion Resources (Dominion), Piedmont and Southern Company Gas announced the formation of Atlantic Coast Pipeline, LLC (ACP) to build and own the proposed Atlantic Coast Pipeline (ACP pipeline), an approximately 600-mile interstate natural gas pipeline running from West Virginia to North Carolina. The ACP pipeline is designed to meet, in part, the needs identified by Duke Energy Carolinas, Duke Energy Progress and Piedmont. Dominion will build and operate the ACP pipeline and holds a leading ownership percentage in ACP of 48 percent. Duke Energy owns a 47 percent interest through its Gas Utilities and Infrastructure segment. Southern Company Gas maintains a 5 percent interest. See Notes 12 and 17 for additional information related to Duke Energy's ownership interest.

Duke Energy Carolinas, Duke Energy Progress and Piedmont, among others, will be customers of the pipeline. Purchases will be made under several 20-year supply contracts, subject to state regulatory approval. On September 18, 2015, ACP filed an application with the FERC requesting a CPCN authorizing ACP to construct the pipeline. ACP executed a construction agreement in September 2016. ACP also requested approval of an open access tariff and the precedent agreements it entered into with future pipeline customers. In December 2016, FERC issued a draft Environmental Impact Statement (EIS) indicating that the proposed pipeline would not cause significant harm to the environment or protected populations. The FERC issued the final EIS in July 2017. On October 13, 2017, FERC issued an order approving the CPCN, subject to conditions. On October 16, 2017, ACP accepted the FERC order subject to reserving its right to file a request for rehearing or clarification on a timely basis. On November 9, 2017, ACP filed a request for rehearing on several limited issues. On December 12, 2017, ACP filed an answer to intervenors’ request for rehearing of the certificate order and for stay of the certificate order.

In December 2017, West Virginia issued a waiver of the state water quality permit in reliance on the U.S. Army Corps of Engineers national water quality permit and Virginia issued a conditional water quality permit subject to completion of additional studies and stormwater plans. In early 2018, the FERC issued a series of Partial Notices to Proceed which authorized the project to begin limited construction-related activities along the pipeline route. North Carolina issued the state water quality permit in January 2018. The project remains subject to other pending federal and state approvals, which will allow full construction activities to begin. The ACP pipeline project has a targeted in-service date of late 2019.

Due to delays in obtaining the required permits to commence construction and the conditions imposed upon the project by the permits, ACP's project manager estimates the project's pipeline development costs have increased from a range of $5.0 billion to $5.5 billion to a range of $6.0 billion and $6.5 billion, excluding financing costs. Project construction activities, schedule and final costs are still subject to uncertainty due to potential additional permitting delays, construction productivity and other conditions and risks which could result in potential higher project costs and a potential delay in the targeted in-service date.

Sabal Trail Transmission Pipeline

On May 4, 2015, Duke Energy acquired a 7.5 percent ownership interest in Sabal Trail Transmission, LLC (Sabal Trail) from Spectra Energy Partners, LP, a master limited partnership, formed by Enbridge Inc. (formerly Spectra Energy Corp.). Spectra Energy Partners, LP holds a 50 percent ownership interest in Sabal Trail and NextEra Energy has a 42.5 percent ownership interest. Sabal Trail is a joint venture to construct a 515-mile natural gas pipeline (Sabal Trail pipeline) to transport natural gas to Florida. Total estimated project costs are approximately $3.2 billion. The Sabal Trail pipeline traverses Alabama, Georgia and Florida. The primary customers of the Sabal Trail pipeline, Duke Energy Florida and Florida Power & Light Company (FP&L), have each contracted to buy pipeline capacity for 25-year initial terms. See Notes 12 and 17 for additional information.

On February 3, 2016, the FERC issued an order granting the request for a CPCN to construct and operate the pipeline. The Sabal Trail pipeline received other required regulatory approvals and the phase one mainline was placed in service in July 2017. On October 12, 2017, Sabal Trail filed a request with FERC to place in-service a lateral line to Duke Energy Florida's Citrus County Combined Cycle facility, which remains pending. This request is required to support commissioning and testing activities at the facility.

On September 21, 2016, intervenors filed an appeal of FERC's CPCN orders to the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit Court of Appeals). On August 22, 2017, the appeals court ruled against FERC in the case for failing to include enough information on the impact of greenhouse-gas emissions carried by the pipeline, vacated the CPCN order and remanded the case to FERC. In response to the August 2017 court decision, the FERC issued a draft Supplemental Environmental Impact Statement (SEIS) on September 27, 2017. On October 6, 2017, FERC and a group of industry intervenors, including Sabal Trail and Duke Energy Florida, filed separate petitions with the D.C. Circuit Court of Appeals requesting rehearing regarding the court's decision to vacate the CPCN order. On January 31, 2018, the D.C. Circuit Court of Appeals denied the requests for rehearing. On February 2, 2018, Sabal Trail filed a request with FERC for expedited issuance of its order on remand and reissuance of the CPCN. In the alternative, the pipeline requested that FERC issue a temporary emergency CPCN to allow for continued operations. On February 5, 2018, FERC issued the final SEIS but did not issue the order on remand. On February 6, 2018, FERC and the intervenors in this case each filed motions for stay with the D.C. Circuit Court to stay the court's mandate. The February 6, 2018 motions automatically stay the issuance of the court’s mandate until the later of seven days after the court denies the motions or the expiration of any stay granted by the court. Both motions are pending. Sabal Trail will continue to monitor the progress and the impact to the project going forward.

Constitution Pipeline

Duke Energy owns a 24 percent ownership interest in Constitution Pipeline Company, LLC (Constitution). Constitution is a natural gas pipeline project slated to transport natural gas supplies from the Marcellus supply region in northern Pennsylvania to major northeastern markets. The pipeline will be constructed and operated by Williams Partners L.P., which has a 41 percent ownership share. The remaining interest is held by Cabot Oil and Gas Corporation and WGL Holdings, Inc. Before the permitting delays discussed below, Duke Energy's total anticipated contributions were approximately $229 million. As a result of the permitting delays and project uncertainty, total anticipated contributions by Duke Energy can no longer be reasonably estimated.

In December 2014, Constitution received approval from the FERC to construct and operate the proposed pipeline. However, on April 22, 2016, the New York State Department of Environmental Conservation (NYSDEC) denied Constitution’s application for a necessary water quality certification for the New York portion of the Constitution pipeline. Constitution filed legal actions in the U.S. Court of Appeals for the Second Circuit (U.S. Court of Appeals) challenging the legality and appropriateness of the NYSDEC’s decision and on August 18, 2017, the petition was denied in part and dismissed in part. In September 2017, Constitution filed a petition for a rehearing of portions of the decision unrelated to the water quality certification, which was denied by the U.S. Court of Appeals. In January 2018, Constitution petitioned the Supreme Court of the United States to review the U.S. Court of Appeals decision. In October 2017, Constitution filed a petition for declaratory order requesting FERC to find that the NYSDEC waived its rights to issue a Section 401 water quality certification by not acting on Constitution's application within a reasonable period of time as required by statute. This petition was based on precedent established by another pipeline’s successful petition with FERC following a District of Columbia Circuit Court ruling. On January 11, 2018, FERC denied Constitution's petition. In February 2018, Constitution filed a rehearing request with FERC of its finding that the NYSDEC did not waive the Section 401 certification requirement. Constitution is currently unable to approximate an in-service date for the project due to the NYDSEC's denial of the water quality certification. The Constitution partners remain committed to the project and are evaluating next steps to move the project forward. Duke Energy cannot predict the outcome of this matter.

Since April 2016, with the actions of the NYSDEC, Constitution stopped construction and discontinued capitalization of future development costs until the project's uncertainty is resolved.

See Notes 12 and 17 for additional information related to ownership interest and carrying value of the investment.

Progress Energy Merger FERC Mitigation

Following the closing of the Progress Energy merger, outside counsel reviewed Duke Energy’s long-term FERC mitigation plan and discovered a technical error in the calculations. On December 6, 2013, Duke Energy submitted a filing to the FERC disclosing the error and arguing that no additional mitigation is necessary. The city of New Bern filed a protest and requested that FERC order additional mitigation. On October 29, 2014, the FERC ordered that the amount of the stub mitigation be increased from 25 MW to 129 MW. The stub mitigation is Duke Energy’s commitment to set aside for third parties a certain quantity of firm transmission capacity from Duke Energy Carolinas to Duke Energy Progress during summer off-peak hours. The FERC also ordered that Duke Energy operate certain phase shifters to create additional import capability and that such operation be monitored by an independent monitor. The costs to comply with this order are not material. The FERC also referred Duke Energy’s failure to expressly designate the phase shifter reactivation as a mitigation project in the original mitigation plan filing in March 2012 to the FERC Office of Enforcement for further inquiry. In response, and since December 2014, the FERC Office of Enforcement has been conducting a nonpublic investigation of Duke Energy's market power analyses included in the Progress merger filings submitted to FERC. Duke Energy cannot predict the outcome of this investigation.

Potential Coal Plant Retirements

The Subsidiary Registrants periodically file Integrated Resource Plans (IRP) with their state regulatory commissions. The IRPs provide a view of forecasted energy needs over a long term (10 to 20 years) and options being considered to meet those needs. Recent IRPs filed by the Subsidiary Registrants included planning assumptions to potentially retire certain coal-fired generating facilities in Florida and Indiana earlier than their current estimated useful lives primarily because facilities do not have the requisite emission control equipment to meet EPA regulations recently approved or proposed.

The table below contains the net carrying value of generating facilities planned for retirement or included in recent IRPs as evaluated for potential retirement due to a lack of requisite environmental control equipment. Dollar amounts in the table below are included in Net property, plant and equipment on the Consolidated Balance Sheets as of December 31, 2017, and exclude capitalized asset retirement costs.

		Remaining Net
	Capacity	Book Value
	(in MW)	(in millions)
Duke Energy Carolinas
Allen Steam Station Units 1-3(a)	585	$	163
Progress Energy and Duke Energy Florida
Crystal River Units 1 and 2(b)	873	107
Duke Energy Indiana
Gallagher Units 2 and 4(c)	280	127
Total Duke Energy	1,738	$	397

(a) Duke Energy Carolinas will retire Allen Steam Station Units 1 through 3 by December 31, 2024, as part of the resolution of a lawsuit involving alleged New Source Review violations.

(b) Duke Energy Florida expects to retire these coal units by the end of 2018 to comply with environmental regulations.

(c) Duke Energy Indiana committed to either retire or stop burning coal at Gallagher Units 2 and 4 by December 31, 2022, as part of the settlement of Edwardsport IGCC matters.

Refer to the "Western Carolinas Modernization Plan" discussion above for details of Duke Energy Progress' planned retirements.