Commitments And Contingencies

3 Months Ended

Mar. 31, 2018

Commitments and Contingencies Disclosure

COMMITMENTS AND CONTINGENCIES

NOTE 13(a) Capital Purchase Obligations - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation and installation of an SCR system at Ottumwa Unit 1 to reduce NOx emissions at the EGU. WPL’s projects include West Riverside. At March 31, 2018, Alliant Energy’s, IPL’s and WPL’s minimum future commitments related to certain contractual obligations for these projects were $95 million, $12 million and $83 million, respectively.

NOTE 13(b) Other Purchase Obligations - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase obligations associated with other goods and services. At March 31, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a)		$1,175		$1,127		$48
Natural gas	892		362		530
Coal (b)	165		88		77
Other (c)	46		26		6
		$2,278		$1,603		$661

(a) Includes payments required by purchased power agreements for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2018 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2018.

NOTE 13(c) Legal Proceedings -

Flood Damage Claims - In 2013, several plaintiffs purporting to represent a class of residential and commercial property owners filed a complaint against Cedar Rapids and Iowa City Railway Company (CRANDIC), Alliant Energy and various other defendants in the Iowa District Court for Linn County. Plaintiffs assert claims of negligence and strict liability based on their allegations that CRANDIC (along with other defendants) caused or exacerbated flooding of the Cedar River in June 2008. In February 2016, the Iowa District Court for Linn County ruled in favor of Alliant Energy and CRANDIC and dismissed all claims against them, resulting in no loss. In August 2016, the Iowa District Court for Linn County dismissed all claims against the remaining defendants. In September 2016, plaintiffs filed a notice of appeal with the Supreme Court of Iowa. Alliant Energy does not currently believe any material losses for this complaint are both probable and reasonably estimated, and therefore has not recognized any material loss contingency amounts as of March 31, 2018.

NOTE 13(d) Guarantees and Indemnifications -

Whiting Petroleum - In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Whiting Petroleum is an independent oil and gas company. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under general partnership agreements in the oil and gas industry, including with respect to the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The guarantees do not include a maximum limit. As of March 31, 2018, the present value of the abandonment obligations is estimated at $34 million. Alliant Energy is not aware of any material liabilities related to these guarantees of which it is probable that Alliant Energy Resources, LLC will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of March 31, 2018.

Non-utility Wind Farm in Oklahoma - In July 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term purchased power agreement. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and purchased power agreement. Alliant Energy’s obligations under the operating agreement were $98 million as of March 31, 2018 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the purchased power agreement are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of March 31, 2018.

IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the July 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of March 31, 2018. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020.

NOTE 13(e) Environmental Matters -

Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At March 31, 2018, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At March 31, 2018, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$11	-	$30		$9	-	$25
Current and non-current environmental liabilities	16				13

WPL Consent Decree - In 2013, the U.S. District Court for the Western District of Wisconsin approved a Consent Decree that WPL, along with the other owners of Edgewater and Columbia, entered into with the EPA and the Sierra Club, thereby resolving claims against WPL. Such claims included allegations that the owners of Edgewater, Nelson Dewey and Columbia violated the Prevention of Significant Deterioration program requirements, Title V Operating Permit requirements of the Clean Air Act (CAA) and the Wisconsin State Implementation Plan designed to implement the CAA.

WPL has completed various requirements under the Consent Decree. WPL’s remaining requirements include installing an SCR system at Columbia Unit 2 and fuel switching or retiring Edgewater Unit 4 by December 31, 2018. The Consent Decree also establishes sulfur dioxide (SO2), NOx and particulate matter emission rate limits for Columbia Units 1 and 2, and Edgewater Units 4 and 5. In addition, the Consent Decree includes annual plant-wide SO2 and NOx emission caps for Columbia and Edgewater. Alliant Energy and WPL currently expect to recover material costs incurred by WPL related to compliance with the terms of the Consent Decree from WPL’s electric customers.

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include installing an SCR system or equivalent NOx reduction system at Ottumwa by December 31, 2019, and fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025.

The Consent Decree also establishes SO2, NOx and particulate matter emission rate limits with varying averaging times for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. In addition, the Consent Decree includes calendar-year SO2 and NOx emission caps for Prairie Creek, and calendar-year SO2 and NOx emission caps in aggregate for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.

Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including carbon emissions from new (CAA Section 111(b)) and existing (CAA Section 111(d)) fossil-fueled EGUs.

IPL [Member]

Commitments and Contingencies Disclosure

COMMITMENTS AND CONTINGENCIES

NOTE 13(a) Capital Purchase Obligations - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation and installation of an SCR system at Ottumwa Unit 1 to reduce NOx emissions at the EGU. WPL’s projects include West Riverside. At March 31, 2018, Alliant Energy’s, IPL’s and WPL’s minimum future commitments related to certain contractual obligations for these projects were $95 million, $12 million and $83 million, respectively.

NOTE 13(b) Other Purchase Obligations - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase obligations associated with other goods and services. At March 31, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a)		$1,175		$1,127		$48
Natural gas	892		362		530
Coal (b)	165		88		77
Other (c)	46		26		6
		$2,278		$1,603		$661

(a) Includes payments required by purchased power agreements for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2018 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2018.

NOTE 13(c) Legal Proceedings -

Flood Damage Claims - In 2013, several plaintiffs purporting to represent a class of residential and commercial property owners filed a complaint against Cedar Rapids and Iowa City Railway Company (CRANDIC), Alliant Energy and various other defendants in the Iowa District Court for Linn County. Plaintiffs assert claims of negligence and strict liability based on their allegations that CRANDIC (along with other defendants) caused or exacerbated flooding of the Cedar River in June 2008. In February 2016, the Iowa District Court for Linn County ruled in favor of Alliant Energy and CRANDIC and dismissed all claims against them, resulting in no loss. In August 2016, the Iowa District Court for Linn County dismissed all claims against the remaining defendants. In September 2016, plaintiffs filed a notice of appeal with the Supreme Court of Iowa. Alliant Energy does not currently believe any material losses for this complaint are both probable and reasonably estimated, and therefore has not recognized any material loss contingency amounts as of March 31, 2018.

NOTE 13(d) Guarantees and Indemnifications -

Whiting Petroleum - In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Whiting Petroleum is an independent oil and gas company. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under general partnership agreements in the oil and gas industry, including with respect to the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The guarantees do not include a maximum limit. As of March 31, 2018, the present value of the abandonment obligations is estimated at $34 million. Alliant Energy is not aware of any material liabilities related to these guarantees of which it is probable that Alliant Energy Resources, LLC will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of March 31, 2018.

Non-utility Wind Farm in Oklahoma - In July 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term purchased power agreement. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and purchased power agreement. Alliant Energy’s obligations under the operating agreement were $98 million as of March 31, 2018 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the purchased power agreement are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of March 31, 2018.

IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the July 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of March 31, 2018. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020.

NOTE 13(e) Environmental Matters -

Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At March 31, 2018, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At March 31, 2018, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$11	-	$30		$9	-	$25
Current and non-current environmental liabilities	16				13

WPL Consent Decree - In 2013, the U.S. District Court for the Western District of Wisconsin approved a Consent Decree that WPL, along with the other owners of Edgewater and Columbia, entered into with the EPA and the Sierra Club, thereby resolving claims against WPL. Such claims included allegations that the owners of Edgewater, Nelson Dewey and Columbia violated the Prevention of Significant Deterioration program requirements, Title V Operating Permit requirements of the Clean Air Act (CAA) and the Wisconsin State Implementation Plan designed to implement the CAA.

WPL has completed various requirements under the Consent Decree. WPL’s remaining requirements include installing an SCR system at Columbia Unit 2 and fuel switching or retiring Edgewater Unit 4 by December 31, 2018. The Consent Decree also establishes sulfur dioxide (SO2), NOx and particulate matter emission rate limits for Columbia Units 1 and 2, and Edgewater Units 4 and 5. In addition, the Consent Decree includes annual plant-wide SO2 and NOx emission caps for Columbia and Edgewater. Alliant Energy and WPL currently expect to recover material costs incurred by WPL related to compliance with the terms of the Consent Decree from WPL’s electric customers.

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include installing an SCR system or equivalent NOx reduction system at Ottumwa by December 31, 2019, and fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025.

The Consent Decree also establishes SO2, NOx and particulate matter emission rate limits with varying averaging times for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. In addition, the Consent Decree includes calendar-year SO2 and NOx emission caps for Prairie Creek, and calendar-year SO2 and NOx emission caps in aggregate for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.

Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including carbon emissions from new (CAA Section 111(b)) and existing (CAA Section 111(d)) fossil-fueled EGUs.

WPL [Member]

Commitments and Contingencies Disclosure

COMMITMENTS AND CONTINGENCIES

NOTE 13(a) Capital Purchase Obligations - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. IPL’s projects include the expansion of wind generation and installation of an SCR system at Ottumwa Unit 1 to reduce NOx emissions at the EGU. WPL’s projects include West Riverside. At March 31, 2018, Alliant Energy’s, IPL’s and WPL’s minimum future commitments related to certain contractual obligations for these projects were $95 million, $12 million and $83 million, respectively.

NOTE 13(b) Other Purchase Obligations - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase obligations associated with other goods and services. At March 31, 2018, minimum future commitments related to these purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a)		$1,175		$1,127		$48
Natural gas	892		362		530
Coal (b)	165		88		77
Other (c)	46		26		6
		$2,278		$1,603		$661

(a) Includes payments required by purchased power agreements for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2018 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2018.

NOTE 13(c) Legal Proceedings -

Flood Damage Claims - In 2013, several plaintiffs purporting to represent a class of residential and commercial property owners filed a complaint against Cedar Rapids and Iowa City Railway Company (CRANDIC), Alliant Energy and various other defendants in the Iowa District Court for Linn County. Plaintiffs assert claims of negligence and strict liability based on their allegations that CRANDIC (along with other defendants) caused or exacerbated flooding of the Cedar River in June 2008. In February 2016, the Iowa District Court for Linn County ruled in favor of Alliant Energy and CRANDIC and dismissed all claims against them, resulting in no loss. In August 2016, the Iowa District Court for Linn County dismissed all claims against the remaining defendants. In September 2016, plaintiffs filed a notice of appeal with the Supreme Court of Iowa. Alliant Energy does not currently believe any material losses for this complaint are both probable and reasonably estimated, and therefore has not recognized any material loss contingency amounts as of March 31, 2018.

NOTE 13(d) Guarantees and Indemnifications -

Whiting Petroleum - In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Whiting Petroleum is an independent oil and gas company. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under general partnership agreements in the oil and gas industry, including with respect to the future abandonment of certain platforms off the coast of California and related onshore plant and equipment owned by the partnerships. The guarantees do not include a maximum limit. As of March 31, 2018, the present value of the abandonment obligations is estimated at $34 million. Alliant Energy is not aware of any material liabilities related to these guarantees of which it is probable that Alliant Energy Resources, LLC will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of March 31, 2018.

Non-utility Wind Farm in Oklahoma - In July 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term purchased power agreement. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and purchased power agreement. Alliant Energy’s obligations under the operating agreement were $98 million as of March 31, 2018 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the purchased power agreement are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of March 31, 2018.

IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the July 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. Alliant Energy and IPL believe the likelihood of having to make any material cash payments under these indemnifications is remote. IPL has not recorded any material liabilities related to these indemnifications as of March 31, 2018. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expire in October 2020.

NOTE 13(e) Environmental Matters -

Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At March 31, 2018, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At March 31, 2018, such amounts for WPL were not material.

	Alliant Energy				IPL
Range of estimated future costs		$11	-	$30		$9	-	$25
Current and non-current environmental liabilities	16				13

WPL Consent Decree - In 2013, the U.S. District Court for the Western District of Wisconsin approved a Consent Decree that WPL, along with the other owners of Edgewater and Columbia, entered into with the EPA and the Sierra Club, thereby resolving claims against WPL. Such claims included allegations that the owners of Edgewater, Nelson Dewey and Columbia violated the Prevention of Significant Deterioration program requirements, Title V Operating Permit requirements of the Clean Air Act (CAA) and the Wisconsin State Implementation Plan designed to implement the CAA.

WPL has completed various requirements under the Consent Decree. WPL’s remaining requirements include installing an SCR system at Columbia Unit 2 and fuel switching or retiring Edgewater Unit 4 by December 31, 2018. The Consent Decree also establishes sulfur dioxide (SO2), NOx and particulate matter emission rate limits for Columbia Units 1 and 2, and Edgewater Units 4 and 5. In addition, the Consent Decree includes annual plant-wide SO2 and NOx emission caps for Columbia and Edgewater. Alliant Energy and WPL currently expect to recover material costs incurred by WPL related to compliance with the terms of the Consent Decree from WPL’s electric customers.

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include installing an SCR system or equivalent NOx reduction system at Ottumwa by December 31, 2019, and fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025.

The Consent Decree also establishes SO2, NOx and particulate matter emission rate limits with varying averaging times for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. In addition, the Consent Decree includes calendar-year SO2 and NOx emission caps for Prairie Creek, and calendar-year SO2 and NOx emission caps in aggregate for Burlington, Lansing, M.L. Kapp, Ottumwa and Prairie Creek. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.

Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including carbon emissions from new (CAA Section 111(b)) and existing (CAA Section 111(d)) fossil-fueled EGUs.