Exhibit 99.1

Great Plains Energy
Wachovia Securities
18th Annual Nantucket Equity Conference

June 24, 2008

Michael Cline, VP - Investor Relations and Treasurer

1

FORWARD-LOOKING STATEMENTS

Statements made in this release that are not based on historical facts are forward-looking, may involve risks and
uncertainties, and are intended to be as of the date when made. Forward-looking statements include, but are not limited to,
statements regarding projected delivered volumes and margins, the outcome of regulatory proceedings, cost estimates of
the comprehensive energy plan and other matters affecting future operations. In connection with the safe harbor provisions
of the Private Securities Litigation Reform Act of 1995, the registrants are providing a number of important factors that could
cause actual results to differ materially from the provided forward-looking information. These important factors include:
future economic conditions in the regional,national and international markets, including but not limited to regional and
national wholesale electricity markets; market perception of the energy industry, Great Plains Energy and KCP&L; changes in
business strategy, operations or development plans; effects of current or proposed state and federal legislative and
regulatory actions or developments, including, but not limited to, deregulation, re-regulation and restructuring of the electric
utility industry; decisions of regulators regarding rates KCP&L can charge for electricity; adverse changes in applicable laws,
regulations, rules, principles or practices governing tax, accounting and environmental matters including, but not limited to,
air and water quality; financial market conditions and performance including, but not limited to, changes in interest rates and
in availability and cost of capital and the effects on pension plan assets and costs; credit ratings; inflation rates;
effectiveness of risk management policies and procedures and the ability of counterparties to satisfy their contractual
commitments; impact of terrorist acts; increased competition including, but not limited to, retail choice in the electric utility
industry and the entry of new competitors; ability to carry out marketing and sales plans; weather conditions including
weather-related damage; cost, availability, quality and deliverability of fuel; ability to achieve generation planning goals and
the occurrence and duration of unplanned generation outages; delays in the anticipated in-service dates and cost increases
of additional generating capacity; nuclear operations; ability to enter new markets successfully and capitalize on growth
opportunities in non-regulated businesses and the effects of competition; workforce risks including compensation and
benefits costs; performance of projects undertaken by non-regulated businesses and the success of efforts to invest in and
develop new opportunities; the ability to successfully complete merger, acquisition or divestiture plans (including the
acquisition of Aquila, Inc., and Aquila’s sale of assets to Black Hills Corporation); and other risks and uncertainties. Other risk
factors are detailed from time to time in Great Plains Energy’s most recent quarterly report on Form 10-Q or annual report
on Form 10-K filed with the Securities and Exchange Commission. This list of factors is not all-inclusive because it is not
possible to predict all factors.

Forward Looking Statement

2

• $2.1 billion market capitalization

• $5.1 billion in total assets at 3/31/08

• $3.3 billion in revenue in FY 2007 (includes $2.0 billion from Strategic
Energy, divested in June 2008)

• Expanding regulated platform with the proposed acquisition of Aquila

Regulated electric utility:

•$146.4 million in core earnings or
$1.72/share in 2007

•506,000 customers in KS and MO

•Total generation capacity: over 4,000 MWs

•Net MWhs generated by fuel type:

»Coal 72%, nuclear 24%, natural gas
and oil 3%, and wind 1%

3

Path to Earnings and Dividend Growth

•Realizable growth in regulated business:

»Pure-play, vertically integrated, regulated electric utility with completed
sale of Strategic Energy

»Aquila transaction complements KCP&L and adds scale and scope

»Rate base growth at KCP&L driven by Comprehensive Energy Plan

•Low-cost generating platform; high reliability and customer satisfaction

•Attractive investment profile:

»Solid dividend with future growth potential - current dividend yield
approximately 6.3%

»Solid investment grade rating

»Executing our growth plan

4

KCP&L Service Territory

Oil

KCP&L

Missouri:

» Public Service Commission of the State of Missouri (MPSC)

» KCP&L’s MO jurisdictional revenues averaged 57% of total revenue in
2004-2007

»Kansas:

» The State Corporation Commission of the State of Kansas (KCC)

» KCP&L’s KS jurisdictional revenues averaged 43% of total revenue in

2004-2007

•Headquartered in Kansas City, Missouri

•Engage in the generation, transmission,
distribution and sale of electricity

•$4.4 billion in assets at 3/31/08

•Serve over 500,000 customers in 24
counties in western Missouri and eastern
Kansas

•Total generation capacity: over 4,000
MWs

•Regulated by commissions in two states:

KCP&L Overview

5

EEI Edison Award - Kansas City Power & Light was recognized for distinguished leadership,
innovation and contribution to the advancement of the electric industry for its Comprehensive
Energy Plan collaboration. (June 2007)

EEI Outstanding Customer Service Awardvoted Kansas City Power & Light the winner of
this award for medium-sized utility. (May 2007)

J.D. Power and Associates recognizes Tier 1 performance. In the Midwest, KCP&L
ranks No. 1 on Communications; No. 2 on Power Quality and Reliability, and Billing and
Payment; and No. 3 in Overall Satisfaction. (February 2007)

2007 ReliabilityOne™ National Reliability Excellence Awardpresented by PA Consulting
Group to Kansas City Power & Light as the most reliable electric utility nationwide. (October
2007)

EEI Emergency Assistance Awardfor outstanding efforts to assist fellow utilities in power
restoration during 2007. (January 2008)

2007 Mid-America Regional Council’s Regional Leadership Awardpresented to Kansas
City Power & Light for its outstanding environmental initiatives in metropolitan Kansas City.
(June 2007)

David Garcia Award for Environmental Excellencepresented by Bridging the Gap for the
groundbreaking Collaborative Agreement with Sierra Club and Concerned Citizens of
Platte County. (October 2007)

Recognized Excellence in 2007

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Other

Residential:

• 446,100 customers

• Revenues: $433.8 million

• 5.6 million MWh sales

Commercial:

• 57,600 customers

• Revenues: $492.1 million

• 7.7 million MWh sales

Industrial:

• 2,300 industrial customers,

• Revenues: $106.8 million

• 2.2 million MWh sales

Customer Mix Based on 2007 Revenues

Note:All numbers for full year / as of year-end 2007

KCP&L - A Steady Retail Customer Base

7

Source:“EEI Typical Bill Rankings Report and Typical Bill/Avg Rates Report for 12 month ended December 2007.”
Note: Rate actions after December 30, 2007, including KCP&L’s new annual rate increases in MO and KS that were
implemented January 1, 2008, are not reflected in this chart

Comparative Rates by Customer Segment

$0.08

$0.10

$0.12

Residential

Commercial

Industrial

Total Retail

KCPL

National Avg.

$0.06

$0.04

$0.02

KCP&L’s Rates Compare Favorably on
National & Regional Basis

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Wind 1%

Natural Gas & Oil - 3%

Nuclear - 24%

Coal - 72%

$1.23

$0.45

$7.30

Fuel cost per net

kWh generated

Fuel Mix1

Fuel Costs

Strong, low cost coal and nuclear generation provides KCP&L

competitive generation fleet in a volatile market

Note:All numbers for full year 2007

1Based on actual net kWh generated

$1.19

Low-Cost Diverse Generating Fleet

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KCP&L’s Comprehensive Energy Plan

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Investing for Future Energy Demands

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Spearville Wind Energy Facility

ü100MW completed on schedule and under budget

LaCygne Environmental Project

üPhase 1: Unit 1 SCR - Completed on schedule, under budget, and
performing per specification

•Phase 2: Unit 1 - bag house and scrubber environmental upgrades:

»Project Definition Report completed in Q3 2007

»Evaluating upgrade of Unit 2 at the same time

Iatan Unit 1 Environmental Project

•Cost / schedule reforecast completed; expected to be in-service early
2009

Iatan Unit 2 Construction

•Cost / schedule reforecast completed; expected to be in-service summer
2010.

Comprehensive Energy Plan Progress

12

Total Iatan 2 Cost per KW

1 AFDC = Allowance for Funds Used During Construction

2 Also excludes initial coal inventory of $14 million

3 Source: Research Reports International

• Difficult construction market conditions generally

• Estimated final cost in line with industry

• Similar projects under Construction, Disclosed $ / KW3

» Excel Energy - Commanche 3, Supercritical 750 MW (estimated completion 2009) $1,733

» Duke Energy - Cliffside, Supercritical 800 MW (estimated completion 2012) $2,250

» GenPower Holdings - Longview, Supercritical 769 MW (estimated completion 2011) $2,367

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•Develop long range resource plan and file Integrated Resource Plan in
Missouri in August 2008

» Plan will also include plant availability resources

•Continue to engage community and regulators to develop energy
efficiency and demand response as resource alternatives:

» Potential energy efficiency projects designed to reduce annual

electricity demand 100MW by 2010; additional 200MW by 2012

•Continue development of environmental and renewable generation
alternatives

•Potential to pursue an additional 400MW wind generation

•Expected future environmental upgrades at LaCygne Unit 2 for BART

and Montrose for CAIR

Developing Sustainable Resource
Strategy

14

1Environmental amounts included in this table are included in the Clean Air Estimated Required

Environmental Expenditures table listed in Great Plains Energy’s First Quarter 2008 10-Q.KCP&L

estimates total remaining required environmental expenditures of $877 million- $1.179 billion.

Note: The table does not reflect expenditures that may be incurred related to the addition of 100 MW

of wind generation by 2010 and 300 additional MW by 2012, subject to regulatory approval, pursuant

to the terms of the Collaboration Agreement.

All numbers from first quarter 2008 10Q

Projected KCP&L Capital Expenditures
2008-2010

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•GXP & KCP&L solid investment grade

» GXP - Senior unsecured rating:Moody’s Baa2; S&P BBB-

» KCP&L - Senior unsecured rating:Moody’s A3; S&P BBB

•GXP and KCP&L are weathering turbulent markets effectively:

» GXP issued $100 million of new 10-year debt in September 2007

» KCP&L issued $350 million of new 10-year bonds in March 2008

» KCP&L converted entire auction rate debt portfolio to fixed rate in
March 2008

» Combined available liquidity of over $700 million as of 3/31/081

•Issuance of equity and debt considerations:

» No additional debt in 2008

» Equity later in the year

•Proceeds from sale of Strategic Energy to partially offset 2008
financing needs

•GXP will not issue ’08 guidance; expect to issue ’09 guidance later in the
year

1Includes GXP and KCP&L as of 3/31/08

Liquidity / Financing / Guidance

Aquila Merger

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•Focused regional acquisition and attractive strategic growth opportunity

•Solid rate base growth plan

•Strong track record of success working with regulatory, political and
community groups

•Adjacent utility territories provide opportunity for integration and
significant synergies

•Shared synergies mitigate future rate increases

•Expected to be modestly dilutive to GXP in 2008 and accretive in 2009
forward

•Investment grade credit rating anticipated to reduce financing costs and
facilitate access to capital

Strategic Rationale

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„Great Plains Energy will acquire Aquila in a stock and cash merger.

„Immediately before the Great Plains Energy transaction, BKH will acquire from Aquila: Colorado Electric & Gas,
Iowa Gas, Kansas Gas, and Nebraska Gas operations for $940 million in cash (subject to adjustment); BKH
has secured $1B bridge financing.

„Transactions are cross-conditioned.

Structure of
Transaction

„ $1.80 per Aquila share in cash (approximately 40%)

„.0856 shares of Great Plains Energy common stock per Aquila share (approximately 60%)

Form of
Consideration

„$4.54 per share based on Great Plains Energy’s closing price on 2/6/07

„Approximately $4.07 per share based on Great Plains Energy’s closing price on 6/16/08

Implied Merger
Consideration

Step 1: Asset Sale Step 2: Merger Step 3: Combined Entity

Black Hills

(BKH)

Aquila

Selected
Assets &
Liabilities

Cash
~$940mm

Great Plains
Energy

Gregory

Acquisition

Corp

Aquila

Aquila

Shareholders

Cash/Stock
$1.80/0.0856

Merger

Aquila

~ 27%

Great Plains

Energy

~ 73%

Great Plains
Energy

KCP&L

Aquila

(renamed)

Deal Structure

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Great Plains Energy
(Baa2 / BBB-)

Aquila

(expected dba KCP&L Greater
Missouri Operations)

(Ba3 / BB-)

KCP&L

(A3 / BBB)

Simplified Post-Transaction Legal
Structure

Note:Credit ratings represent senior unsecured ratings
assigned by Moody’s and S&P, respectively, as of June 23, 2008

•Separate legal and
regulatory entities

•Combined
operationally

20

+

FORGING A STRONGER

REGIONAL UTILITY

üStrong support for transaction from
shareholders of both companies

üFERC approval received

üNebraska, Iowa, & Colorado approval of Black
Hills transaction

üKansas approval for Black Hills and Great
Plains Energy transactions

üMissouri hearings concluded on May 1;
awaiting final Commission order

•Transaction currently anticipated to close in
mid-July

Aquila Transaction Update

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Great Plains Energy expects to realize $675 million of total savings
and synergies over five years

Interest Savings

Corporate Retained
& Merchant Savings

$302

$305

$68

$120

$131

$54

$27

$275

Significant Synergies Expected

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2009 and beyond: Extend the platform

•Complete and include Iatan 1 AQCS in rates effective in 2009

•400 MW of additional wind to be evaluated

•Complete Iatan 2

•Integrate Aquila and deliver synergies

•Additional environmental spending at LaCygne 1 and potentially LaCygne 2

•Continue with sound strategic planning to effectively meet future generation
requirements and as an industry leader in energy efficiency

•Increased earnings driven by investments and enhanced by opportunities in
Aquila’s service territory.Expected dividend growth, with a traditional
target payout ratio, to follow

A Path to Growth

Great Plains Energy

Wachovia Securities
18th Annual Nantucket Equity Conference

June 24, 2008

Michael Cline, VP - Investor Relations and Treasurer

Great Plains Energy

Appendix

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Core earnings is a non-GAAP financial measure that differs from GAAP earnings because it excludes the effects of certain unusual items and mark-to-market gains and losses on energy
contracts. Great Plains Energy believes core earnings provides to investors a meaningful indicator of its results that is comparable among periods because it excludes the effects of items
that may not be indicative of Great Plains Energy’s prospective earnings potential.Core earnings is used internally to measure performance against budget and in reports for management
and the Board of Directors and are a component, subject to adjustment, of employee and executive compensation plans. Investors should note that this non-GAAP measure involves
judgments by management, including whether an item is classified as an unusual item, and Great Plains Energy’s definition of core earnings may differ from similar terms used by other
companies. The impact of these items could be material to operating results presented in accordance with GAAP. Great Plains Energy is unable to reconcile core earnings guidance to
GAAP earnings per share because it does not predict the future impact of unusual items and mark-to-market gains or losses on energy contracts.

26

Core earnings is a non-GAAP financial measure that differs from GAAP earnings because it excludes the effects of certain unusual items and mark-to-market gains and losses on energy
contracts. Great Plains Energy believes core earnings provides to investors a meaningful indicator of its results that is comparable among periods because it excludes the effects of items that
may not be indicative of Great Plains Energy’s prospective earnings potential. Core earnings is used internally to measure performance against budget and in reports for management and the
Board of Directors and are a component, subject to adjustment, of employee and executive incentive compensation plans. Investors should note that this non-GAAP measure involves
judgments by management, including whether an item is classified as an unusual item, and Great Plains Energy’s definition of core earnings may differ from similar terms used by other
companies. The impact of these items could be material to operating results presented in accordance with GAAP. Great Plains Energy is unable to reconcile core earnings guidance to GAAP
earnings per share because it does not predict the future impact of unusual items and mark-to-market gains or losses on energy contracts.