Exhibit 99.1

FOR IMMEDIATE RELEASE February 18, 2011		Analyst Contact: Britta Carlson, (702) 402-5624 Media Contact: Karl Walquist, (775) 834-3891

NV Energy, Inc., Reports 2010 Earnings

Las Vegas — NV Energy, Inc. (NYSE: NVE) today announced consolidated net income of $227 million, or 97 cents per share basic and 96 cents per share diluted, for the year ended December 31, 2010, compared with consolidated net income of $182.9 million, or 78 cents per share basic and diluted, for the same period in 2009.

Earnings for the year were positively influenced by the general rate increase at our Southern Nevada Utility effective July 1, 2009, and continued focus on controlling spending.

“We are pleased with our 2010 earnings especially in light of the slower growth in Nevada,” said Michael Yackira, President and Chief Executive Officer of NV Energy, Inc. “We continue to focus on controllable costs and operational efficiencies in the implementation of our three-part energy strategy.”

Webcast Scheduled for 7 a.m. PST today, Friday, February 18, 2011

Senior management of NV Energy will review the company’s 2010 and fourth quarter financial results and other matters during a conference call and live webcast today, Friday, February 18, at 7 a.m. Pacific Standard Time.

The webcast will be accessible on the NV Energy website:

www.nvenergy.com.

An archived version of the webcast will remain on the NV Energy website for approximately one month following the live webcast. To listen to a recording of the call by telephone, call (800) 475-6701, and international callers should dial (320) 365-3844. Use the conference call access code, 189772, to listen to the recording.

Headquartered in Las Vegas, NV Energy, Inc. is a holding company whose principal subsidiaries, Nevada Power Company and Sierra Pacific Power Company, are doing business as NV Energy. Serving a 44,424 -square-mile service territory that stretches north to south from Elko to Laughlin, NV Energy provides a wide range of energy services and products to approximately 2.4 million citizens of Nevada as well as approximately 40 million tourists annually.

This press release may contain forward-looking statements regarding the future performance of NV Energy, Inc. and its subsidiaries, Nevada Power Company and Sierra Pacific Power Company both d/b/a NV Energy, within the meaning of the Private Securities Litigation Reform Act of 1995. These statements are subject to a variety of risks and uncertainties that could cause

actual results to differ materially from current expectations. These risks and uncertainties include, but are not limited to, NV Energy Inc.’s ability to maintain access to the capital markets, NV Energy Inc.’s ability to receive dividends from its subsidiaries, the financial performance of NV Energy Inc.’s subsidiaries, particularly Nevada Power Company and Sierra Pacific Power Company both d/b/a NV Energy, and the discretion of NV Energy Inc.’s Board of Directors with respect to the payment of future dividends based on its periodic review of factors that ordinarily affect dividend policy, such as current and prospective financial condition, earnings and liquidity, prospective business conditions, regulatory factors, and dividend restrictions in NV Energy Inc.’s and its subsidiaries’ financing agreements. For Nevada Power Company and Sierra Pacific Power Company both d/b/a NV Energy, these risks and uncertainties include, but are not limited to, future economic conditions both nationally and regionally, changes in the rate of industrial, commercial and residential growth in their service territories, their ability to procure sufficient renewable energy sources in each compliance year to satisfy the Nevada Renewable Energy Portfolio Standard, changes in environmental laws and regulations, construction risks, their ability to maintain access to the capital markets for general corporate purposes and to finance construction projects, employee workforce factors, including changes in and renewals of collective bargaining agreements, strikes or work stoppages, unseasonable weather, drought, threat of wildfire and other natural phenomena, explosions, fires, accidents, mechanical breakdowns that may occur while operating and maintaining an electric and natural gas system, their ability to purchase sufficient fuel, natural gas and power to meet their power demands and natural gas demands for Sierra Pacific Power Company d/b/a NV Energy, financial market conditions, and unfavorable rulings in their pending and future regulatory filings. Additional cautionary statements regarding other risk factors that could have an effect on the future performance of NV Energy, Inc., Nevada Power Company and Sierra Pacific Power Company both d/b/a NV Energy are contained in their quarterly reports on Form 10-Q for the quarter ended September 30, 2010, and Form 10-Q and as amended by Form 10-Q/A for the quarters ended March 31, 2010 and June 30, 2010, and their Annual Reports on Form 10-K and 10-K/A for the year ended December 31, 2009, each filed with the SEC. NV Energy Inc., Nevada Power Company and Sierra Pacific Power Company both d/b/a NV Energy undertake no obligation to release publicly the result of any revisions to these forward-looking statements that may be made to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events.

NV ENERGY, INC.
CONSOLIDATED INCOME STATEMENTS
(Dollars in Thousands, Except Per Share Amounts)

										Three Months Ended
		Year ended December 31,								December 31,
		2010				2009				2010				2009
OPERATING REVENUES		$	3,280,222			$	3,585,798			$	655,011			$	772,883
OPERATING EXPENSES:
Fuel for power generation			821,484				881,768				170,970				197,294
Purchased power			648,881				758,736				126,343				124,551
Gas purchased for resale			137,702				153,607				36,166				52,150
Deferred energy			113,107				289,076				6,553				74,021
Other operating expenses			414,241				453,413				93,486				120,858
Maintenance			104,567				102,309				18,852				20,090
Depreciation and amortization			333,059				321,921				83,992				81,009
Taxes other than income			62,746				60,885				15,214				17,308
Total Operating Expenses			2,635,787				3,021,715				551,576				687,281
OPERATING INCOME			644,435				564,083				103,435				85,602
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)			(333,010	)			(334,314	)			(91,385	)			(83,318	)
Interest income (expense) on regulatory items			(12,517	)			(2,280	)			(3,764	)			(1,407	)
AFUDC — equity			28,112				24,274				7,197				5,181
Other income			36,841				33,122				6,317				1,913
Other expense			(23,113	)			(26,498	)			(6,075	)			(9,073	)
Total Other Income (Expense)			(303,687	)			(305,696	)			(87,710	)			(86,704	)
Income (Loss) Before Income Tax Expense			340,748				258,387				15,725				(1,102	)
Income tax expense (benefit)			113,764				75,451				1,512				(5,253	)
NET INCOME		$	226,984			$	182,936			$	14,213			$	4,151
Amount per share basic and diluted
Net Income per share — basic		$	0.97			$	0.78			$	0.06			$	0.02
Net Income per share — diluted		$	0.96			$	0.78			$	0.06			$	0.02
Outstanding — basic			235,048,347				234,542,292				235,048,347				234,728,309
Outstanding — diluted			236,294,812				235,180,688				236,294,812				235,644,043
Dividends Declared Per Share of Common Stock		$	0.45			$	0.41			$	0.12			$	0.11

NEVADA POWER COMPANY
CONSOLIDATED INCOME STATEMENTS
(Dollars in Thousands)

										Three Months Ended
		Year ended December 31,								December 31,
		2010				2009				2010				2009
OPERATING REVENUES		$	2,252,377			$	2,423,377			$	416,233			$	477,559
OPERATING EXPENSES:
Fuel for power generation			588,419				587,647				119,137				132,292
Purchased power			505,239				627,759				92,963				86,013
Deferred energy			94,843				207,611				13,124				62,701
Other operating expenses			260,535				279,865				56,762				73,094
Maintenance			71,759				71,019				12,814				12,739
Depreciation and amortization			226,252				215,873				56,922				55,004
Taxes other than income			37,918				37,241				9,061				10,847
Total Operating Expenses			1,784,965				2,027,015				360,783				432,690
OPERATING INCOME			467,412				396,362				55,450				44,869
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)			(214,367	)			(226,252	)			(52,871	)			(55,717	)
Interest income (expense) on regulatory items			(3,169	)			3,463				(1,204	)			572
AFUDC — equity			25,229				21,025				6,674				4,467
Other income			15,541				19,658				6,457				932
Other expense			(12,946	)			(18,320	)			(3,608	)			(5,985	)
Total Other Income (Expense)			(189,712	)			(200,426	)			(44,552	)			(55,731	)
Income (Loss) Before Income Tax Expense			277,700				195,936				10,898				(10,862	)
Income tax expense (benefit)			91,757				61,652				1,341				(4,205	)
NET INCOME (Loss)		$	185,943			$	134,284			$	9,557			$	(6,657	)

SIERRA PACIFIC POWER COMPANY
CONSOLIDATED INCOME STATEMENTS
(Dollars in Thousands)

										Three Months Ended
		Year ended December 31,								December 31,
		2010				2009				2010				2009
OPERATING REVENUES:
Electric		$	836,879			$	957,130			$	187,542			$	222,744
Gas			190,943				205,263				51,232				72,577
Total Operating Revenues			1,027,822				1,162,393				238,774				295,321
OPERATING EXPENSES:
Fuel for power generation			233,065				294,121				51,833				65,002
Purchased power			143,642				130,977				33,380				38,538
Gas purchased for resale			137,702				153,607				36,166				52,150
Deferred energy — electric — net			8,475				73,829				(8,714	)			5,607
Deferred energy — gas — net			9,789				7,636				2,143				5,713
Other operating expenses			149,946				170,849				35,575				47,101
Maintenance			32,808				31,290				6,038				7,351
Depreciation and amortization			106,807				106,048				27,070				26,005
Taxes other than income			24,593				23,447				6,099				6,401
Total Operating Expenses			846,827				991,804				189,590				253,868
OPERATING INCOME			180,995				170,589				49,184				41,453
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)			(68,514	)			(69,413	)			(17,373	)			(17,940	)
Interest income (expense) on regulatory items			(9,348	)			(5,743	)			(2,560	)			(1,979	)
AFUDC — equity			2,883				3,249				523				714
Other income			16,748				13,276				2,472				977
Other expense			(9,985	)			(7,648	)			(2,430	)			(3,047	)
Total Other Income (Expense)			(68,216	)			(66,279	)			(19,368	)			(21,275	)
Income Before Income Tax Expense			112,779				104,310				29,816				20,178
Income tax expense			40,404				31,225				10,338				5,299
NET INCOME		$	72,375			$	73,085			$	19,478			$	14,879

Gross margin is presented by Nevada Power Company and Sierra Pacific Power Company both d/b/a NV Energy in order to provide information that management believes aids the reader in determining how profitable the electric and gas business is at the most fundamental level. Gross margin, which is a “non-GAAP financial measure” as defined in accordance with SEC rules, provides a measure of income available to support the other operating expenses of the business and is utilized by management in its analysis of its business.

Nevada Power Company and Sierra Pacific Power Company both d/b/a NV Energy believe presenting gross margin allows the reader to assess the impact of regulatory treatment and their overall regulatory environment on a consistent basis. Gross margin, as a percentage of revenue, is primarily impacted by the fluctuations in electric and natural gas supply costs versus the fixed

rates collected from customers. While these fluctuating costs impact gross margin as a percentage of revenue, they only impact gross margin amounts if the costs cannot be passed through to customers. Gross margin, which Nevada Power Company and Sierra Pacific Power Company both d/b/a NV Energy calculate as operating revenues less energy costs, provides a measure of income available to support the other operating expenses. Gross margin changes are based primarily on general base rate adjustments (which are required to be filed by statute every three years). Reconciliations between GAAP operating income and gross margin are provided in tables herein. These non-GAAP measures should not be considered as substitutes for the GAAP measures.

RECONCILIATION OF NON-GAAP FINANCIAL MEASURES
Gross Margin
(Dollars in Thousands)
(Unaudited)

Nevada Power Company
										Change from
		2010				2009				Prior Year %
Operating Revenues:
Electric		$	2,252,377			$	2,423,377				-7.1	%
Energy Costs:
Fuel for power generation			588,419				587,647
Purchased power			505,239				627,759
Deferred energy			94,843				207,611
			1,188,501				1,423,017				-16.5	%
Gross Margin		$	1,063,876			$	1,000,360				6.3	%
Other operating expenses			260,535				279,865
Maintenance			71,759				71,019
Depreciation and amortization			226,252				215,873
Taxes other than income			37,918				37,241
Operating Income		$	467,412			$	396,362				17.9	%

Sierra Pacific Power Company

										Change from
		2010				2009				Prior Year %
Operating Revenues:
Electric		$	836,879			$	957,130
Gas			190,943				205,263
		$	1,027,822			$	1,162,393				-11.6	%
Energy Costs:
Fuel for power generation			233,065				294,121
Purchased power			143,642				130,977
Deferred energy -electric-net			8,475				73,829
Gas purchased for resale			137,702				153,607
Deferred energy -gas-net			9,789				7,636
		$	532,673			$	660,170				-19.3	%
Energy Costs by Segment:
Electric		$	385,182			$	498,927
Gas			147,491				161,243
		$	532,673			$	660,170
Gross Margin by Segment:
Electric		$	451,697			$	458,203
Gas			43,452				44,020
		$	495,149			$	502,223				-1.4	%
Other operating expenses			149,946				170,849
Maintenance			32,808				31,290
Depreciation and amortization			106,807				106,048
Taxes other than income			24,593				23,447
Operating Income		$	180,995			$	170,589				6.1	%

Summary of Selected Operating Statistics

Nevada Power Company
Electric Operating Revenue
(dollars in thousands)

										Change from				Avg. Change
		2010				2009				Prior Year %				in customers
Electric Operating Revenues:
Residential		$	1,084,497			$	1,143,836				-5.2	%			0.4	%
Commercial			436,343				477,477				-8.6	%			0.8	%
Industrial			663,586				720,850				-7.9	%			0.3	%
Retail revenues			2,184,426				2,342,163				-6.7	%
Other			67,951				81,214				-16.3	%
Total Revenues		$	2,252,377			$	2,423,377				-7.1	%
Retail sales in thousands of MWhs			20,642				20,957				-1.5	%

Sierra Pacific Power Company
Electric Operating Revenue
(dollars in thousands)

										Change from				Avg. Change
		2010				2009				Prior Year %				in customers
Electric Operating Revenues:
Residential		$	303,737			$	345,455				-12.1	%			0.2	%
Commercial			321,599				381,805				-15.8	%			0.1	%
Industrial			178,855				199,510				-10.4	%			-1.8	%
Retail revenues			804,191				926,770				-13.2	%
Other			32,688				30,360				7.7	%
Total Revenues		$	836,879			$	957,130				-12.6	%
Retail sales in thousands of MWhs			8,081				8,162				-1.0	%

Sierra Pacific Power Company
Gas Operating Revenue
(dollars in thousands)

										Change from				Avg. Change
		2010				2009				Prior Year %				in customers
Gas Operating Revenues:
Residential		$	102,923			$	116,680				-11.8	%
Commercial			45,547				52,186				-12.7	%
Industrial			14,802				17,458				-15.2	%
Retail revenues			163,272				186,324				-12.4	%			0.8	%
Wholesale revenue			25,233				16,560				52.4	%
Miscellaneous			2,438				2,379				2.5	%
Total Revenues		$	190,943			$	205,263				-7.0	%
Retail sales in thousands of decatherms			14,739				15,046				-2.0	%

Summary of Selected Operating Statistics

Nevada Power Company
MWH Sales
(in MWh’s)

										Change from
		2010				2009				Prior Year %
Retail:
Residential			8,684,386				8,893,542				-2.4	%
Commercial & Industrial
Gaming/Recreation/Restaurants			3,215,710				3,392,658				-5.2	%
All Other Retail			8,742,166				8,670,931				0.8	%
Total Retail			20,642,262				20,957,131				-1.5	%
Wholesale			1,262				69,915				-98.2	%
Sales to Public Authorities			231,072				240,302				-3.8	%
Total			20,874,596				21,267,348				-1.8	%

Sierra Pacific Power Company
MWH Sales
(in MWh’s)

										Change from
		2010				2009				Prior Year %
Retail:
Residential			2,465,049				2,502,537				-1.5	%
Commercial and Industrial:
Mining			1,506,866				1,405,087				7.2	%
All Other Retail			4,108,834				4,254,749				-3.4	%
Total Retail			8,080,749				8,162,373				-1.0	%
Wholesale			13,797				14,993				-8.0	%
Sales to Public Authorities			16,459				16,535				-0.5	%
Total			8,111,005				8,193,901				-1.0	%

Financial Highlights
(Dollars in Thousands)
(Unaudited)

NV Energy, Inc
Capital Structure		December 31, 2010								December 31, 2009
Current maturities of long-term debt		$	355,929				4.1	%		$	134,474				1.6	%
Long-term debt			4,924,109				57.1	%			5,303,357				61.2	%
Total Debt		$	5,280,038				61.2	%		$	5,437,831				62.8	%
Total shareholders’ equity			3,350,818				38.8	%			3,223,922				37.2	%
Total Capitalization (including current maturities of long-term debt)		$	8,630,856				100.0	%		$	8,661,753				100.0	%

Nevada Power Company
Capital Structure		December 31, 2010								December 31, 2009
Current maturities of long-term debt		$	355,929				5.6	%		$	119,474				1.9	%
Long-term debt			3,221,833				50.8	%			3,535,440				56.1	%
Total Debt		$	3,577,762				56.4	%		$	3,654,914				58.0	%
Total shareholder’s equity			2,761,632				43.6	%			2,650,039				42.0	%
Total Capitalization (including current maturities of long-term debt)		$	6,339,394				100.0	%		$	6,304,953				100.0	%

Sierra Pacific Power Company
Capital Structure		December 31, 2010								December 31, 2009
Current maturities of long-term debt		$	—				0.0	%		$	15,000				0.6	%
Long-term debt			1,195,775				55.1	%			1,282,225				55.6	%
Total Debt		$	1,195,775				55.1	%		$	1,297,225				56.2	%
Total shareholder’s equity			973,420				44.9	%			1,009,258				43.8	%
Total Capitalization (including current maturities of long-term debt)		$	2,169,195				100.0	%		$	2,306,483				100.0	%

NVE Available Liquidity as of December 31, 2010 (dollars in millions)
		NVE				NPC				SPPC
Cash and Cash Equivalents		$	13.6			$	60.1			$	9.6
Balance available on Revolving Credit Facilities			N/A				585.3				219.3
Less reduction for hedging obligations			N/A				(28.3	)			(13.8	)
		$	13.6			$	617.1			$	215.1