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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2000

OR

For the transition period from                to                

   Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes /x/ No / /

   Northern States Power Company (a Minnesota corporation), Northern States Power Company (a Wisconsin corporation), Public Service Company of Colorado and Southwestern Public Service Company meet the conditions set forth in General Instruction I(1)(a) and (b) of Form 10-K and are therefore filing this Form 10-K with the reduced disclosure format specified in General Instruction I (2) to such Form 10-K.

   Indicate the number of shares outstanding of each of the issuer's classes of common stock, as of the latest practicable date. All outstanding common stock is owned beneficially and of record by Xcel Energy Inc., a Minnesota corporation. Shares outstanding at March 15, 2001:

Index

    This combined Form 10-K is separately filed by Northern States Power Company, a Minnesota corporation (NSP-Minnesota), Northern States Power Company, a Wisconsin corporation (NSP-Wisconsin), Public Service Company of Colorado (PSCo) and Southwestern Public Service Company (SPS). NSP-Minnesota, NSP-Wisconsin, PSCo and SPS are all wholly owned subsidiaries of Xcel Energy Inc. Additional information on Xcel Energy is available on various filings with the SEC. Information in this report relating to any individual company is filed by such company on its own behalf. Each registrant makes representation only to itself and makes no representations as to information relating to the other registrants. This report should be read in its entirety.

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Item l—Business

COMPANY OVERVIEW

    On Aug. 18, 2000, New Century Energies, Inc. (NCE) and Northern States Power Co. (NSP) merged and formed Xcel Energy Inc. Xcel Energy, a Minnesota corporation, is a registered holding company under the Public Utility Holding Company Act (PUHCA). Each share of NCE common stock was exchanged for 1.55 shares of Xcel Energy common stock. NSP shares became Xcel Energy shares on a one-for-one basis. The merger was structured as a tax-free, stock-for-stock exchange for shareholders of both companies (except for fractional shares), and accounted for as a pooling-of-interests. As part of the merger, NSP transferred its existing utility operations that were being conducted directly by NSP at the parent company level to a newly formed subsidiary of Xcel Energy named Northern States Power Company.

    Xcel Energy directly owns six utility subsidiaries that serve electric and natural gas customers in 12 states. These six utility subsidiaries are Northern States Power Company, a Minnesota corporation (NSP-Minnesota), Northern States Power Company, a Wisconsin corporation (NSP-Wisconsin), Public Service Company of Colorado (PSCo), Southwestern Public Service Company (SPS), Black Mountain Gas Company (BMG) and Cheyenne Light, Fuel and Power Company (Cheyenne). Their service territories include portions of Arizona, Colorado, Kansas, Michigan, Minnesota, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Wisconsin and Wyoming. Xcel Energy's regulated businesses also include Viking Gas Transmission Company and WestGas InterState Inc. (WGI), both interstate natural gas pipeline companies.

    Xcel Energy also owns or has an interest in a number of nonregulated businesses, the largest of which is NRG Energy, Inc., a publicly traded independent power producer. At Dec. 31, 2000, Xcel Energy indirectly owned 82 percent of NRG. Xcel Energy owned 100 percent of NRG until the second quarter 2000, when NRG completed its initial public offering. During March 2001, NRG issued an additional 18.4 million shares of common stock, which caused Xcel Energy's ownership interest in NRG to decline to approximately 75 percent.

    In addition to NRG, Xcel Energy's nonregulated subsidiaries include Seren Innovations, Inc. (broadband telecommunications services), e prime, inc. (natural gas marketing and trading), Planergy International Inc. (energy management, consulting and demand-side management services) and Eloigne Company (acquisition of rental housing projects that qualify for low-income housing tax credits). Xcel Energy also reports in its nonregulated activities its 50-percent stake in Yorkshire Power, a regional electricity company in the United Kingdom. Subsequent to year-end, Xcel Energy has agreed to sell a substantial portion of this investment.

    Xcel Energy owns the following additional direct subsidiaries, some of which are intermediate holding companies with additional subsidiaries: Xcel Energy Wholesale Group, Inc., Xcel Energy Markets Holdings Inc., Xcel Energy International Inc., Xcel Energy Ventures Inc., Xcel Energy Retail Holdings Inc., Xcel Energy Communications Group Inc., Xcel Energy WYCO Inc., Xcel Energy O&M Services Inc. and Xcel Energy Services Inc. Xcel Energy and its subsidiaries collectively are referred to as Xcel Energy.

NSP-Minnesota

    NSP-Minnesota was incorporated in 2000 under the laws of Minnesota. NSP-Minnesota is an operating utility engaged in the generation, transmission and distribution of electricity and the transportation, storage and distribution of natural gas. NSP-Minnesota provides generation, transmission and distribution of electricity in Minnesota, North Dakota and South Dakota. NSP-Minnesota also purchases, distributes and sells natural gas to retail customers and transports customer-owned gas in Minnesota, North Dakota and South Dakota. NSP-Minnesota provides retail

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electric utility service to approximately 1.3 million customers and gas utility service to approximately 0.4 million customers.

    NSP-Minnesota owns the following direct subsidiaries: United Power and Land Co., which holds real estate; First Midwest Auto Park Inc., which owns and operates a parking ramp; NSP Nuclear Corp., which holds NSP-Minnesota's interest in the Nuclear Management Company; and NSP Financing I, a special purpose business trust.

NSP-Wisconsin

    NSP-Wisconsin was incorporated in 1901 under the laws of Wisconsin. NSP-Wisconsin is an operating utility engaged in the generation, transmission and distribution of electricity to approximately 225,000 retail customers in northwestern Wisconsin and in the western portion of the Upper Peninsula of Michigan. NSP-Wisconsin is also engaged in the distribution and sale of natural gas in the same service territory to approximately 85,000 customers in Wisconsin and Michigan.

    NSP-Wisconsin owns the following direct subsidiaries: Chippewa and Flambeau Improvement Company, which operates hydro reserves; Clearwater Investments Inc., which owns interests in affordable housing; and NSP Lands, Inc., which hold real estate.

PSCo

    PSCo was incorporated in 1924 under the laws of Colorado. PSCo is an operating utility engaged principally in the generation, purchase, transmission, distribution and sale of electricity and the purchase, transportation, distribution and sale of natural gas. PSCo serves approximately 1.2 million electric customers and approximately 1.1 million gas customers in Colorado.

    PSCo owns the following direct subsidiaries: 1480 Welton, Inc., which owns certain real estate interests of PSCo; P.S.R. Investments, Inc., which owns and manages permanent life insurance policies on certain employees; PS Colorado Credit Corporation, a finance company that finances certain of PSCo's current assets; and Green and Clear Lakes Company, which owns water rights. PSCo also holds a controlling interest in several other relatively small ditch and water companies whose capital requirements are not significant.

SPS

    SPS was incorporated in 1921 under the laws of New Mexico. SPS is an operating utility engaged primarily in the generation, transmission, distribution and sale of electricity. SPS serves approximately 390,000 electric customers in portions of Texas, New Mexico, Oklahoma and Kansas. The wholesale customers served by SPS comprise approximately 34 percent of the total kilowatt-hour sales.

UTILITY REGULATION

Ratemaking Principles

    The utility subsidiaries of Xcel Energy are subject to the jurisdiction of the Securities and Exchange Commission (SEC) under PUHCA. The rules and regulations under PUHCA generally limit the operations of a registered holding company to a single integrated public utility system, plus additional energy-related businesses. PUHCA rules require that transactions between affiliated companies in a registered holding company system be performed at cost, with limited exceptions.

    The FERC has jurisdiction over wholesale rates for electric transmission service and electric energy sold in interstate commerce, hydro facility licensing and certain other activities of Xcel Energy's utility subsidiaries. Federal, state and local agencies also have jurisdiction over many of Xcel Energy's other activities.

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    The utility subsidiaries of Xcel Energy are unable to predict the impact on their operating results from the future regulatory activities of any of these agencies. The utility subsidiaries of Xcel Energy strive to comply with all rules and regulations issued by the various agencies.

NSP-Minnesota

    Retail rates, services and other aspects of NSP-Minnesota's operations are subject to the jurisdiction of the Minnesota Public Utilities Commission (MPUC), the North Dakota Public Service Commission (NDPSC) and the South Dakota Public Utilities Commission (SDPUC) within their respective states. The MPUC also possesses regulatory authority over aspects of NSP-Minnesota's financial activities, including security issuances, certain property transfers, mergers with other utilities and transactions between NSP-Minnesota and its affiliates. In addition, the MPUC reviews and approves NSP-Minnesota's electric resource plans and gas supply plans for meeting customers' future energy needs.

    The Minnesota Environmental Quality Board (MEQB) is empowered to select and designate sites for new power plants with a capacity of 50 megawatts or more and wind energy conversion plants with a capacity of five megawatts or more. It also designates routes for electric transmission lines with a capacity of 200 kilovolts (kv) or more. No power plant or transmission line may be constructed in Minnesota except on a site or route designated by the MEQB.

NSP-Wisconsin

    NSP-Wisconsin is subject to regulation of similar scope by the Public Service Commission of Wisconsin (PSCW) and the Michigan Public Service Commission (MPSC). In addition, each of the state commissions certifies the need for new generating plants and electric and retail gas transmission lines of designated capacities to be located within the respective states before the facilities may be sited and built.

    The PSCW has a biennial filing requirement. By June of each odd-numbered year, NSP-Wisconsin must submit rate filings for calendar years beginning the following January. The filing procedure and review generally allow the PSCW sufficient time to issue an order effective with the start of the test year.

PSCo

    PSCo is subject to the jurisdiction of the Colorado Public Utility Commission (CPUC) with respect to its facilities, rates, accounts, services and issuance of securities. PSCo is subject to the jurisdiction of the FERC with respect to its wholesale electric operations and accounting practices and policies. PSCo has received authorization from the FERC to act as a power marketer. Also, PSCo holds a FERC certificate that allows it to transport natural gas in interstate commerce without PSCo becoming subject to full FERC jurisdiction.

SPS

    The Public Utility Commission of Texas (PUCT) has jurisdiction over SPS' Texas operations as an electric utility and original and appellate jurisdiction over its retail rates and services. The New Mexico Public Regulatory Commission (NMPRC) has jurisdiction over the issuance of securities and accounting. The NMPRC, the Oklahoma Corporation Commission and the Kansas Corporation Commission have jurisdiction with respect to retail rates and services in their respective states. The FERC has jurisdiction over SPS' rates for sales for resale and the transmission of electricity in interstate commerce.

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Fuel, Purchased Gas and Resource Adjustment Clauses

NSP-Minnesota

    NSP-Minnesota's retail electric rate schedules provide for adjustments to billings and revenues for changes in the cost of fuel and purchased energy. NSP-Minnesota is permitted to recover option costs through a fuel clause adjustment, a mechanism that allows NSP-Minnesota to bill customers for the actual cost of fuel used to generate electricity at its plants and energy purchased from suppliers. Changes in capacity charges are not recovered through the fuel clause. NSP-Minnesota's electric wholesale customers do not have a fuel clause provision in their contracts. Instead, the contracts have an escalation factor.

    Gas rate schedules for NSP-Minnesota include a purchased gas adjustment (PGA) clause that provides for rate adjustments for changes in the current unit cost of purchased gas compared with the last costs included in rates. The PGA factors in Minnesota are calculated for the current month based on the estimated purchased gas costs for that month.

    By September of each year, NSP-Minnesota is required to submit to the MPUC an annual report of the PGA factors used to bill each customer class by month for the previous year commencing July 1 and ending June 30. The report verifies whether the utility is calculating the adjustments properly and implementing them in a timely manner. In addition, the MPUC reviews procurement policies, cost-minimizing efforts, rule variances, retail transportation gas volumes, independent auditors' reports and the impact of market forces on gas costs for the coming year. The MPUC has the authority to disallow certain costs if it finds the utility was not prudent in its gas procurement activities.

    NSP-Minnesota is required by Minnesota law to spend a minimum of 2 percent of Minnesota electric revenue and 0.5 percent of Minnesota gas revenue on conservation improvement programs (CIP). These costs are recovered through an annual recovery mechanism for electric and gas conservation and energy management program expenditures. NSP-Minnesota is required to request a new cost recovery level annually.

NSP-Wisconsin

    NSP-Wisconsin does not have an automatic electric fuel adjustment clause for Wisconsin retail customers. Instead, it has a procedure that compares actual monthly and anticipated annual fuel costs with those costs that were included in the latest retail electric rates. If the comparison results in a difference outside a prescribed range, the PSCW may hold hearings limited to fuel costs and revise rates. Any revised rates would be effective until the next rate case. The adjustment approved is calculated on an annual basis, but applied prospectively. Most of NSP-Wisconsin's wholesale electric rate schedules provide for adjustments to billings and revenues for changes in the cost of fuel and purchased energy.

    During 1999, the PSCW approved a new gas cost recovery mechanism to replace the PGA. The financial impact of the gas cost recovery mechanism is substantially the same as with the former PGA.

    NSP-Wisconsin's gas and retail electric rate schedules for Michigan customers include gas cost recovery factors and power supply cost recovery factors, which are based on 12-month projections. After each 12-month period, a reconciliation is submitted whereby over-collections are refunded and any under-collections are collected from the customers.

PSCo

    PSCo has five adjustment clauses: the incentive cost adjustment (ICA), the gas cost adjustment (GCA), the steam cost adjustment (SCA), the demand side management cost adjustment (DSMCA) and the qualifying facilities capacity cost adjustment (QFCCA). These adjustment clauses allow certain

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costs to be passed through to retail customers. PSCo is required to file applications with the CPUC for approval of adjustment mechanisms in advance of the proposed effective dates. The applications must be acted upon before becoming effective.

    The ICA allows for an equal sharing between customers and shareholders of certain fuel and energy cost increases. PSCo, through its GCA, is allowed to recover its actual costs of purchased gas. The GCA rate is revised annually in October, and otherwise as needed, to coincide with changes in purchased gas costs. Purchased gas costs and revenues received to recover such gas costs are compared on a monthly basis and differences are deferred. PSCo, through its SCA, is allowed to recover the difference between its actual cost of fuel and the amount of these costs recovered under its base rates. The SCA rate is revised annually in January, and otherwise as needed, to coincide with changes in fuel costs. The QFCCA provides for recovery of purchased capacity costs from certain QF projects not otherwise reflected in base electric rates.

    The DSMCA clause currently permits PSCo to recover DSM costs over five years while non-labor incremental expenses and carrying costs associated with deferred DSM costs are recovered on an annual basis. PSCo also has implemented a low-income energy assistance program. The costs of this energy conservation and weatherization program for low-income customers are recovered through the DSMCA.

SPS

    Fuel and purchased power costs are recoverable in Texas through a fixed fuel factor, which is part of SPS' rates. If it appears that SPS will materially over-recover or under-recover these costs, the factor may be revised upon application by SPS or action by the PUCT. The rule requires refunding and surcharging under/over-recovery amounts, including interest, when they exceed 4 percent of the utility's annual fuel and purchased power costs, as allowed by the PUCT, if this condition is expected to continue. PUCT regulations require periodic examination of SPS fuel and purchased power costs, the efficiency of the use of such fuel and purchased power, fuel acquisition and management policies and purchase power commitments. Under the PUCT's regulations, SPS is required to file an application for the PUCT to retrospectively review at least every three years the operations of SPS' electric generation and fuel management activities.

    The NMPRC regulations provide for a fuel and purchased power cost adjustment clause and a fixed annual fuel factor for SPS' New Mexico retail jurisdiction. SPS files monthly and annual reports of its fuel and purchased power costs with the NMPRC, which include the current over/under fuel collection calculation, plus interest. In addition, SPS revises its fixed fuel factor annually to recover projected fuel and purchased power costs as well as any over/under cost balance for the current year. SPS is required to petition for a change in the fixed fuel factor if the over/under recovery balance reaches $5 million.

Regulatory Matters

NSP-Minnesota

    Conservation Recovery—NSP-Minnesota had a 4.1 percent conservation rate surcharge in place since 1998, pending resolution of the conservation incentive recovery issue. On July 31, 2000, the MPUC approved NSP-Minnesota's request to prospectively reduce the surcharge level to 0.68 percent (consistent with current costs to be recovered) and to refund cumulative overcollections of approximately $24 million. The refund occurred during December 2000. Although cash flows were reduced, NSP-Minnesota did not have any earnings impact from these actions due to accruals previously recorded. For more information, see Management's Discussion and Analysis under Item 7.

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    Fuel Clause Adjustment—In June 2000, the MPUC approved a change under which bills received by NSP-Minnesota's electricity customers will more accurately reflect energy costs on a timely basis. Previously, the adjustment reflected prior period costs, and it would take approximately three months for customer bills to reflect higher, or lower, fuel costs incurred by NSP-Minnesota. Under the new method, NSP-Minnesota bases the customer billing adjustment on projected energy costs for the current month, and corrects, in a subsequent month, any differences between projected costs and actual costs incurred. This improved matching between costs and usage should encourage customers to take appropriate steps to reduce energy use during peak periods—when costs are at their highest—while giving appropriate price signals when costs are lower during off-peak periods. NSP-Minnesota implemented the revised fuel clause adjustment with July 2000 billings.

    Energy Cost Recovery—In April 2000, the Minnesota Office of Attorney General (OAG) filed a petition with the MPUC asking the MPUC to initiate an investigation of NSP-Minnesota's fuel and purchased energy cost recoveries under the FCA provisions of NSP's tariffs. The OAG alleged NSP-Minnesota could be improperly diverting low-cost NSP-Minnesota generation supplies to the wholesale market to increase profits, while recovering higher-cost energy purchases through the FCA. NSP-Minnesota contends that it has followed the appropriate FCA rules and regulations. In July 2000, the MPUC issued an order in which it indicated that the record before the MPUC did not reflect any specific allegations of wrongdoing. However, the MPUC instructed NSP-Minnesota and the OAG to resolve any concerns and file a report with the MPUC. The report in pending.

    North Dakota Rate Case—In October 2000, NSP-Minnesota filed a request with the NDPSC to increase natural gas rates by approximately 3.3 percent, or $1.4 million, annually. Evidentiary hearings are scheduled for April 2001 with an order likely during the second quarter of 2001.

NSP-Wisconsin

    Temporary Fuel Cost Surcharge—In May 2000, the PSCW issued an order granting a fuel surcharge to increase electric rates to recover higher fuel costs. The increase was primarily the result of higher purchased power costs than were anticipated in base rates. The surcharge factor increased revenues by approximately $6.4 million in 2000 and represented an average increase for all customer classes of approximately 2 percent. The surcharge factor is expected to be effective through Dec. 31, 2001.

PSCo

    Gas Rate Case—In July 2000, PSCo filed a retail rate case with the CPUC requesting an annual increase in its gas revenues of approximately $40 million. The request for a rate increase reflects revenues for additional plant investment, a 12.5-percent return on equity, new depreciation rates and recovery of the dismantlement costs associated with the Leyden Gas Storage facility. In February 2001, the CPUC granted an increase in gas revenues of $14.2 million and authorized an 11.25-percent return on equity. The CPUC did not grant the new depreciation rates proposed by PSCo, but rather granted new depreciation rates proposed by the CPUC staff. The CPUC denied recovery of the dismantlement costs associated with the Leyden Gas Storage facility in this case and recommended PSCo request recovery in a later case.

SPS

    Fuel Recovery—At least every three years, SPS is required to file an application for the PUCT to retrospectively review the operations of a utility's electricity generation and fuel management activities. In June 2000, SPS filed an application for the PUCT to retrospectively review the operations of the utility's electricity generation and fuel management activities. In this application, SPS filed its reconciliation for generation and fuel management activities totaling approximately $419 million, for

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the period from January 1998 through December 1999. SPS expects to be granted recovery of these costs. Final approval is pending.

    SPS filed an application in July 2000 seeking to increase its fixed fuel factors as a result of recent increases in natural gas costs. In August 2000, SPS filed a second application seeking authority to surcharge approximately $26 million in fuel under-recoveries and related interest accrued through the June 2000 billing cycle over the eight months ending May 2001. In August 2000, the PUCT consolidated these two filings into one docket. SPS reached a unanimous stipulation with all parties to the case resolving all outstanding issues. This stipulation was approved by the PUCT in September 2000, which allowed the new fuel factors and surcharge factors to become effective in the October 2000 billing cycle.

    In October 2000, SPS filed an unopposed motion with the NMPRC, seeking to change the date for the implementation of its next fixed annual fuel factor. SPS was approximately $12.8 million under-collected in fuel and purchased power costs through August 2000 and projected that these under-collections would continue based on recent increases in natural gas costs. In October 2000, the NMPRC approved SPS' revised fixed annual fuel factor to be effective in the November 2000 billing cycle.

    In November 2000, SPS filed an application with the PUCT seeking authority to surcharge approximately $43 million in fuel under recoveries and related interest accrued during July 2000 through September 2000. SPS reached a unanimous stipulation with all parties to the case resolving all outstanding issues. In January 2001, the PUCT approved the surcharge and required amounts be applied to customers bills over an eleven-month period starting February 2001.

    For more information on regulatory matters, see Management's Discussion and Analysis under Item 7.

ELECTRIC UTILITY OPERATIONS

Competition and Industry Restructuring

    Retail competition and the unbundling of regulated energy service could have a significant financial impact on Xcel Energy and its subsidiaries, due to an impairment of assets, a loss of retail customers, lower profit margins and increased costs of capital. The total impacts of restructuring may have a significant financial impact on the financial position, results of operations and cash flows of Xcel Energy. Xcel Energy and its utility subsidiaries cannot predict when they will be subject to changes in legislation or regulation, nor can they predict the impacts of such changes on their financial position, results of operations or cash flows. Xcel Energy believes that the prices its utility subsidiaries charge for electricity and the quality and reliability of their service currently place them in a position to compete effectively in the energy market.

    Retail Business Competition—The retail electric business faces increasing competition as industrial and large commercial customers have some ability to own or operate facilities to generate their own electric energy. In addition, customers may have the option of substituting other fuels, such as natural gas for heating, cooling and manufacturing purposes, or the option of relocating their facilities to a lower cost environment. While each of Xcel Energy's utility subsidiaries face these challenges, these subsidiaries believe their rates are competitive with currently available alternatives. Xcel Energy's utility subsidiaries are taking actions to lower operating costs and are working with their customers to analyze energy efficiency, load management and cogeneration in order to better position Xcel Energy's utility subsidiaries to more effectively operate in a competitive environment.

    Wholesale Business Competition—The wholesale electric business faces increasing competition in the supply of bulk power, due to federal and state initiatives to provide open access to utility transmission systems. Under current FERC rules, utilities are required to provide wholesale open-access transmission services and to unbundle wholesale merchant and transmission operations. Xcel Energy's

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utility subsidiaries are operating under a joint tariff in compliance with these rules. To date, these provisions have not had a material impact on the operations of Xcel Energy's utility subsidiaries.

NSP-Minnesota

    Minnesota Restructuring—During the summer of 2000, the Commerce Commissioner, Attorney General, Senate Majority Leader and House Speaker all publicly identified the potential shortage in electric supply as a critical issue for the coming legislative session. Each of these leaders expressed hesitation about adopting a comprehensive restructuring proposal, but they acknowledged the need for reforms in our power supply regulatory system. The Minnesota Chamber of Commerce still intends to push for a comprehensive restructuring bill. Based on the recommendations made by the Department of Commerce in their report "Keeping the Lights On," it is likely that reform of utility taxation and generation and transmission siting will be two of the issues debated by the 2001 Legislature.

    North Dakota Restructuring—In 1997, the North Dakota Legislature established an Electric Utility Committee charged with studying the impact of competition on the electric industry. The committee has six years to study the impact of competition on the electric energy industry in the state. During 2000, the committee began the study of the current tax structure on the industry. The committee was also given the responsibility for assessing the need for modifications to the Territorial Integrity Act, a law governing distribution service territories within the state. The final report presented to the legislative council made no recommendations to change the current tax structure at the present time. The committee will resume its work after the 2001 legislative session.

    In December 2000, the NDPSC approved Xcel Energy's "PLUS" Performance Based Regulation proposal, effective January 2001 for its electric operations in the state. The plan establishes performance standards for reliability, customer service, price and employee safety. The company's performance determines its allowed return on equity. The plan also includes revenue sharing and a price cap mechanism. The plan will remain in effect through 2005.

NSP-Wisconsin

    Wisconsin Restructuring—During 1999, Wisconsin state lawmakers passed "Reliability 2000" legislation, which included steps necessary to further progress toward a restructured industry, eventually including allowing retail customers to choose their electric supplier. One of the provisions of the legislation establishes a public benefits fund, to be administered by the State of Wisconsin, which will use money collected from Wisconsin utilities' customers to pay for low-income assistance, conservation programs and renewable energy and environmental research programs. NSP-Wisconsin began collecting the public benefits surcharge from its Wisconsin customers in October 2000.

    In April 1998, Wisconsin state legislators enacted a law that includes provisions that require the PSCW to order a public utility that owns transmission facilities in Wisconsin to transfer control of its transmission facilities to an independent system operator (ISO) or divest its interest in its transmission facilities to an independent transmission company (ITC) by June 2000. NSP-Minnesota and NSP-Wisconsin joined the Midwest ISO (MISO) in 1999 and filed for PSCW and FERC approval in March 2000. The MISO is not expected to be operational until November 2001. In June 2000, the PSCW issued an order that effectively waived the deadline for the state's five major utilities, including NSP-Wisconsin, to relinquish transmission system control. In October 2000, the PSCW issued an order authorizing NSP-Wisconsin's transfer of operating control of its transmission system to the MISO.

    Michigan Restructuring—In June 2000, Michigan's "Customer Choice and Electricity Reliability Act," became law. The passage of the Act means there will be customer choice for all customers in Michigan, including NSP-Wisconsin's customers in the Upper Peninsula, starting January 2002. Key elements of the law include developing distribution reliability and performance standards and environmental and fuel disclosure standards, codes of conduct, customer and employee education

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programs and an Upper Peninsula Market Power Study. The Act also contains a number of consumer protection provisions dealing with cramming, slamming and low-income energy assistance. NSP-Wisconsin filed its preliminary restructuring plan in October 2000 and revisions to the preliminary restructuring plan in February 2001. NSP-Wisconsin expects to file its unbundled rates by June 2001. The five-percent rate reduction and rate freeze ordered in the Act does not apply to NSP-Wisconsin or other utilities with less than 1 million customers in Michigan.

PSCo

    Colorado Restructuring—During 1998, a bill was passed in Colorado that established an advisory panel to conduct an evaluation of electric industry restructuring and customer choice. During 1999, this panel concluded that Colorado would not significantly benefit from opening its markets to retail competition.

SPS

    New Mexico Restructuring—In April 1999, New Mexico enacted the Electric Utility Restructuring Act of 1999, which provides for customer choice. The legislation provides for recovery of no less than 50 percent of stranded costs for all utilities. Transition costs must be approved by the NMPRC prior to being recovered through a non-bypassable wires charge, which must be included in transition plan filings. SPS must separate its utility operations into at least two entities: energy generation and competitive services, and transmission and distribution utility services, either by the creation of separate affiliates that may be owned by a common holding company or by the sale of assets to one or more third parties. A regulated company, in general, is prohibited from providing unregulated services. In May 2000, the NMPRC approved:

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customer choice for residential, small commercial and educational customers by January 2002;



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customer choice for commercial and industrial customers by July 2002; and



•

completion of SPS corporate separation by August 2001.

    The NMPRC has reopened its electric restructuring rulemakings to consider the impacts on New Mexico electricity markets arising from the volatile California electricity market conditions. In addition, in February 2001, the New Mexico Senate approved a bill that would delay the implementation of restructuring and retail choice until 2007. The House has yet to act on the proposal to delay. We cannot predict the changes that may result from reconsideration of the restructuring legislation or the NMPRC's reconsideration of its regulations as a result of the continuing and significant conditions in the California markets.

    Texas Restructuring—In June 1999, an electric utility restructuring act (SB-7) was passed in Texas, which provides for the implementation of retail competition for most areas of the state, including SPS' service area, beginning January 2002. The PUCT can delay the date for full retail competition if a power region is unable to offer fair competition and reliable service during the 2001 pilot projects. The legislation requires:

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a rate freeze for all customers until January 2002;



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an annual earnings test through 2001;



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a 6-percent rate reduction for those residential and small commercial customers who choose not to switch suppliers at the start of retail competition;



•

the unbundling of business activities, costs and rates relating to generation, transmission and distribution, and retail services;



•

reductions in nitrogen oxide and sulfur dioxide emissions; and

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the recovery of stranded costs.

    SB-7 requires each utility to unbundle its business activities into three separate legal entities: a power generation company, a regulated transmission and distribution company, and a retail electric provider. SB-7 limits the market share that a single generation provider can control to 20 percent of the generating capacity within a qualified power region. The establishment of a qualified power region with multiple generation suppliers is required under SB-7 in order to implement full retail competition. SPS must return any excess earnings indicated in the annual earnings tests above its last allowed rate of return for 1999, 2000 and 2001 or alternatively may direct any excess earnings to improvements in transmission and distribution facilities, to capital expenditures to improve air quality or to accelerate the amortization of regulatory assets, subject to PUCT approval.

    The Texas Legislature is currently considering amendments to SB-7 that would delay the implementation of business separation and customer choice in SPS' market area for five years.

    For more information on restructuring in Texas and New Mexico, see Note 10 to the Financial Statements under Item 8.

    Kansas Restructuring—In 1999, the Kansas Corporation Commission investigated the adequacy of generation capacity of Kansas utilities. The Commission ordered the staff to continually monitor the generation capacity situation in Kansas, ensure the regular filing of information by utilities to meet their responsibility to provide electric service to retail customers and consider the opening of a new docket for conservation appeals.

    Oklahoma Restructuring—The Electric Restructuring Act of 1997 was enacted in Oklahoma during 1997. This legislation directs a series of studies, which will define the orderly transition to consumer choice of electric energy supplier by July 1, 2002. The Electric Restructuring Act was modified during 1998 to clarify terms used in the original bill, as well as advance timelines for studies of the Joint Electric Utility Task Force in order to meet the stated implementation date. In 1998, this task force began the formation of groups, which will examine numerous restructuring issues. A report was issued in 1999. The 2001 legislative session will consider the task force's findings as it considers issues related to implementing customer choice in 2002.

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Capacity and Demand

    Assuming normal weather during 2001, system peak demand and the net dependable system capacity for Xcel Energy's electric utility subsidiaries are projected below. The electric production and transmission system of NSP-Minnesota and NSP-Wisconsin are managed as an integrated system (referred to as the NSP System). The system peak demand for each of the last three years and the forecast for 2001 is listed below.

    The peak demand for the NSP System, PSCo and SPS all typically occurs in the summer. The 2000 system peak demand for the NSP System occurred on Aug. 14, 2000. The 2000 system peak demand for PSCo occurred on Aug. 9, 2000. The 2000 system peak demand for SPS occurred on Aug. 3, 2000.

Energy Sources

    Xcel Energy's utility subsidiaries expect to use the following resources to meet their net dependable system capacity requirements: 1) Xcel Energy's electric generating stations, 2) purchases from other utilities, independent power producers and power marketers, 3) demand-side management options and 4) phased expansion of existing generation at select power plants.

Purchased Power

    Xcel Energy's electric utility subsidiaries have contractual arrangements to purchase power from other utilities and nonregulated energy suppliers. Capacity, typically measured in kilowatts or megawatts, is the measure of the rate at which a particular generating source produces electricity. Energy, typically measured in kilowatt-hours or megawatt-hours, is a measure of the amount of electricity produced from a particular generating source over a period of time. Purchase power contracts typically provide for a charge for the capacity from a particular generating source and a charge for the associated energy actually purchased from such generating source.

    The utility subsidiaries of Xcel Energy also make short-term and non-firm purchases to replace generation from company owned units that is unavailable due to maintenance and unplanned outages, to provide each utility's reserve obligation, to obtain energy at a lower cost than that which could be produced by other resource options, including company owned generation and/or long-term purchase power contracts, and for various other operating requirements.

NSP System Resource Plan

    During 2000, NSP-Minnesota filed an electric resource plan for the NSP System with the MPUC for the period 2000 to 2015. The plan describes how Xcel Energy intends to meet the energy needs of the NSP System and includes an approximate schedule of the timing of resource solicitation to meet such needs. The plan contains conservation programs to reduce the NSP System's peak demand and conserve overall electricity use, an approximate schedule of power purchase solicitations to meet increasing demand and programs and plans to maintain the reliable operation of existing resources. In summary, the plan:

•

forecasts 1.6-percent annual growth in the NSP System's energy and peak demand requirements;



•

outlines NSP System's demand side management and conservation programs;



•

shows new capacity needs of up to 600 megawatts by 2005 and 4,200 megawatts by 2015;

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•

describes the programs for achieving the mandated renewable energy sources of 425 megawatts of wind and 125 megawatts of biomass (NSP-Minnesota contracted for all 125 megawatts of biomass energy, but 80 megawatts of wind energy remains to be contracted); and



•

updates the status of spent nuclear fuel at the Prairie Island plant and describes how it can continue to operate through the end of its license given different alternatives for storing spent nuclear fuel.

    The resource plan proposes to satisfy the NSP System resource needs through the following energy source options:

•

continued use of existing generation facilities, including the repowering of Black Dog Units 1 and 2;



•

demand reduction of an additional 910 megawatts by 2015 through conservation and load management;



•

425 megawatts of wind energy and 125 megawatt of biomass energy under contract by 2002; and



•

acquisition of competitively priced resources through competitive bidding.

    The MPUC is currently reviewing this resource plan. Key issues are the amount of demand side management investment, nuclear spent fuel storage and its impact on future resource needs and assumptions made regarding unaccounted for operating costs of wind. NSP-Minnesota expects the MPUC to issue an order about this resource plan in mid-2001.

PSCo Resource Plan

    PSCo estimates it will purchase approximately 37 percent of its total electric system energy input for 2001. Approximately 36 percent of the total system capacity for the summer 2001 system peak demand for PSCo will be provided by purchased power.

    To meet the demand and energy needs of the rapidly growing economy in Colorado, PSCo recently completed a solicitation process that will add approximately 1,800 megawatts of resources to its system over the 2002-2005 time period. PSCo expects that purchased capacity will continue to meet a significant portion of system requirements at least through 2016.

Purchased Transmission Services

    Xcel Energy's electric utility subsidiaries have contractual arrangements with regional transmission service providers to deliver power and energy to the subsidiaries' native load customers (retail and wholesale load obligations with terms of more than one year). Point-to-point transmission services typically include a charge for the specific amount of transmission capacity being reserved, although some agreements may base charges on the amount of metered energy delivered. Network transmission services include a charge for the metered demand at the delivery point at the time of the provider's monthly transmission system peak, usually calculated as a 12-month rolling average.

Fuel Supply and Costs

    The following tables present the delivered cost per million Btu of each category of fuel consumed by the system for electric generation during the years indicated, the percentage of total fuel

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requirements represented by each category of fuel and the weighted average cost of all fuels during such years.

*

Includes refuse-derived fuel and wood

NSP-Minnesota and NSP-Wisconsin

    NSP-Minnesota and NSP-Wisconsin normally maintain between 20 and 40 days of coal inventory at each plant site. NSP-Minnesota and NSP-Wisconsin have long-term contracts providing for the delivery of up to 100 percent of 2001 coal requirements and up to 70 percent of their 2002 requirements. Coal delivery may be subject to short-term interruptions or reductions due to transportation problems, weather and availability of equipment.

    NSP-Minnesota and NSP-Wisconsin expect that all of the coal they burn in 2001 will have a sulfur content of less than 1 percent. NSP-Minnesota and NSP-Wisconsin have contracts for a maximum of 21.4 million tons of low-sulfur coal for the next two years. The contracts are with two Montana coal suppliers and four Wyoming suppliers. NSP-Minnesota and NSP-Wisconsin could purchase approximately 5 percent of their coal requirements in the spot market in 2001 and 45 percent of coal requirements in 2002 if spot prices are more favorable than contracted prices.

    Estimated coal requirements at NSP-Minnesota's major coal-fired generating plants and the coal supply for such requirements are approximately 12 million tons per year, which is covered by contracts with expiration dates that vary between 2001 and 2003.

    NSP-Minnesota and NSP-Wisconsin's current fuel oil inventory is adequate and they have access to additional spot purchase supplies to meet anticipated 2001 requirements. Additional oil may be obtained through spot purchases.

    To operate NSP-Minnesota's nuclear generating plants, NSP-Minnesota secures contracts for uranium concentrates, uranium conversion, uranium enrichment and fuel fabrication. The contract strategy involves a portfolio of spot purchases and medium- and long-term contracts for uranium, conversion and enrichment. Current contracts are flexible and cover 100 percent of uranium, conversion and enrichment requirements through the year 2001. These contracts expire at varying times between 2001 and 2005. The overlapping nature of contract commitments will allow NSP-Minnesota to maintain 50 percent to 100 percent coverage beyond 2001. NSP-Minnesota expects sufficient uranium,

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conversion and enrichment to be available for the total fuel requirements of its nuclear generating plants. Fuel fabrication is 100 percent committed through 2004 and 30 percent committed through 2010.

PSCo

    PSCo's primary fuel for its steam electric generating stations is low-sulfur western coal. PSCo's coal requirements are purchased primarily under seven long-term contracts with suppliers operating in Colorado and Wyoming. During 2000, PSCo's coal requirements for existing plants were approximately 9.9 million tons, a substantial portion of which was supplied pursuant to long-term supply contracts. Coal supply inventories at Dec. 31, 2000, were approximately 33 days usage, based on the average burn rate for all of PSCo's coal-fired plants.

    PSCo operates the Hayden Station, and has partial ownership in the Craig Station, in Colorado. All of Hayden Station's generating requirements are supplied under a long-term agreement. More than 75 percent of PSCo's Craig Station coal requirements are supplied under two long-term agreements. Any remaining Craig Station requirements for PSCo are supplied via spot coal purchases.

    PSCo has secured more than 75 percent of Cameo Station's coal requirements for 2001 and 2002. Any remaining requirements may be purchased from this contract or the spot market. PSCo has contracted for long-term coal supplies to supply approximately 40 percent of the Cherokee and Valmont Stations' projected requirements in 2001. In addition, PSCo has contracted for substantially all of Cherokee's and Valmont's remaining projected 2001 coal needs.

    PSCo has long-term coal supply agreements for the Pawnee and Comanche Stations' projected requirements. Under the long-term agreements, the supplier has dedicated specific coal reserves at the contractually defined mines to meet the contract quantity obligations. In addition, PSCo has a coal supply agreement to supply approximately 80 percent of Arapahoe Station's projected requirements for 2001. Any remaining Arapahoe Station requirements will be procured via spot purchases.

    PSCo uses both firm and interruptible natural gas and standby oil in combustion turbines and certain boilers. Natural gas supplies for PSCo's power plants are procured under short- and intermediate-term contracts on a competitive basis to provide an adequate supply of fuel.

SPS

    SPS purchases all of its coal requirements for Harrington and Tolk electric generating stations from TUCO Inc., in the form of crushed, ready-to burn coal delivered to SPS' plant bunkers. For the Harrington station the coal supply contract expires in 2016 and the coal-handling agreement expires in 2004. For the Tolk station, the coal supply contract expires in 2017 and the coal-handling agreement expires in 2005. At Dec. 31, 2000, coal inventories at the Harrington and Tolk sites were approximately 30 and 32 days supply, respectively. TUCO has a long-term coal supply agreement to supply approximately 55 percent of Harrington's projected requirements in 2001. TUCO has long term contracts for supply of coal in sufficient quantities to meet the primary needs of the Tolk station.

    SPS has a number of short and intermediate contracts with natural gas suppliers operating in gas fields with long life expectancies in or near its service area. SPS also utilizes firm and interruptible transportation to minimize fuel costs during volatile market conditions and to provide reliability of supply. SPS maintains sufficient gas supplies under short- and intermediate-term contracts to meet all power plant requirements; however, due to flexible contract terms, approximately 55 percent of SPS' gas requirements during 2000 were purchased under spot agreements.

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Nuclear Power Operations and Waste Disposal

    NSP-Minnesota owns two nuclear generating plants: the Monticello plant and the Prairie Island plant. Monticello began operation in 1971 and is licensed to operate until 2010. Prairie Island units 1 and 2 began operation in 1973 and 1974 and are licensed to operate until 2013 and 2014, respectively.

    Nuclear power plant operation produces gaseous, liquid and solid radioactive wastes. The discharge and handling of such wastes are controlled by federal regulation. High-level radioactive waste includes used nuclear fuel. Low-level radioactive waste consists primarily of demineralizer resins, paper, protective clothing, rags, tools and equipment that has become contaminated through use in the plant.

    Federal law places responsibility on each state for disposal of its low-level radioactive waste. Low-level radioactive waste from NSP-Minnesota's Monticello and Prairie Island nuclear plants is currently disposed of at the Barnwell facility, located in South Carolina (all classes of low-level waste), and the Clive facility, located in Utah (class A low-level waste only). Chem Nuclear is the owner and operator of the Barnwell facility, which has been given authorization by South Carolina to accept low-level radioactive waste from out of state. Envirocare, Inc. operates the Clive facility. NSP-Minnesota and Barnwell currently operate under an annual contract, while NSP-Minnesota uses the Envirocare facility through various low-level waste processors. NSP-Minnesota has low-level storage capacity available on-site at Prairie Island and Monticello that would allow both plants to continue to operate until the end of their licensed life, if off-site low-level disposal facilities were not available to NSP-Minnesota.

    The federal government has the responsibility to dispose of, or permanently store, domestic spent nuclear fuel and other high-level radioactive wastes. The Nuclear Waste Policy Act requires the Department of Energy (DOE) to implement a program for nuclear waste management. This includes the siting, licensing, construction and operation of a repository for domestically produced spent nuclear fuel from civilian nuclear power reactors and other high-level radioactive wastes at a permanent storage or disposal facility by 1998. None of NSP-Minnesota's spent nuclear fuel has yet been accepted by the DOE for disposal. See Item 3—Legal Proceedings and Note 13 to the Financial Statements under Item 8 for further discussion of this matter.

    NSP-Minnesota has on-site storage for spent nuclear fuel at its Monticello and Prairie Island nuclear plants. NSP-Minnesota has expanded the used nuclear fuel storage facilities at its Monticello plant by replacement of the racks in the storage pool and by shipping 1,058 used fuel assemblies to a General Electric storage facility. The Monticello plant is expected to have sufficient pool storage capacity to the end of its current operating license in 2010.

    The Prairie Island spent fuel pool has undergone two storage rack replacements. The on-site storage pool for spent nuclear fuel at Prairie Island was nearly filled and adequate space was no longer available. In 1994, a Minnesota law was enacted authorizing NSP-Minnesota to install 17 spent fuel casks for storage of spent nuclear fuel at Prairie Island. NSP-Minnesota has determined 17 casks will allow facility operation until 2007. As of Dec. 31, 2000, 12 storage casks were loaded and stored on the Prairie Island nuclear generating plant site. The Minnesota Legislature established several energy resource requirements and other commitments for NSP-Minnesota to obtain the Prairie Island temporary nuclear fuel storage facility approval. NSP-Minnesota has implemented programs to meet the legislative commitments.

    NSP-Minnesota is part of a consortium of private parties working to establish a private facility for interim storage of spent nuclear fuel. In 1997, Private Fuel Storage LLC (PFS) filed a license application with the Nuclear Regulatory Commission (NRC) for a national temporary storage site for spent nuclear fuel. The PFS will undertake the development, licensing, construction and operation of a storage facility on the Skull Valley Indian Reservation in Utah. The NRC license review process consists of formal evidentiary hearings and opportunity for public input. Storage cask certification

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efforts are continuing, with one cask vendor on track to meet the project goals. The interim used fuel storage facility could be operational and able to accept the first shipment of spent nuclear fuel by 2004. However, due to uncertainty regarding regulatory and governmental approvals, it is possible that this interim storage may be delayed or not available at all.

    In March 2001, NSP-Minnesota signed a contract with Steam Generator Team Ltd. to perform engineering and construction services for the installation of replacement generators at the Prairie Island nuclear power plant. NSP-Minnesota is evaluating the economics of replacing two 25-year-old steam generators on unit 1 at the plant. NSP-Minnesota is taking steps to preserve the replacement option for as early as 2004. The total cost of replacing the steam generators is estimated to be approximately $132 million.

    The NRC has issued a number of regulations, bulletins and orders that require analyses, modification and additional equipment at commercial nuclear power plants. The NRC is engaged in various ongoing studies and rulemaking activities that may impose additional requirements upon commercial nuclear power plants. Management is unable to predict any new requirements or their impact on NSP-Minnesota's facilities and operations.

Nuclear Management Company (NMC)

    During 1999, NSP-Minnesota, Wisconsin Electric Power Co., Wisconsin Public Service Corp. and Alliant Energy established the NMC. The four companies operate seven nuclear units at five sites, with a total generation capacity exceeding 3,650 megawatts.

    During the second quarter of 2000, the Nuclear Regulatory Commission (NRC) approved requests by NMC's four affiliated utilities to transfer operating authority for their five nuclear plants to NMC. NRC action paves the way for NMC to assume management of operations and maintenance at the five plants. The NRC also is considering requests from three intervenors for hearings regarding NSP-Minnesota's application. NMC responsibilities will include oversight of on-site dry storage facilities for used nuclear fuel at the Point Beach and Prairie Island nuclear plants. Utility plant owners will continue to own the plants, control all energy produced by the plants and retain responsibility for nuclear liability insurance and decommissioning costs. The transfer of operating authority will formally establish NMC as an operating company, with a senior management team focused on sharing best practices. Existing personnel will continue to provide day-to-day plant operations, with the additional benefit of tapping into ideas from all NMC-operated plants for improved safety, reliability and operational performance.

    During the third quarter of 2000, NMC and Consumers Energy (CE) reached an agreement for the NMC to operate CE's 789-megawatt Palisades nuclear plant in Covert, Mich. The addition of Palisades gives NMC 4,500 megawatts of generation, making it the sixth largest operator of nuclear plants in the United States.

    For further discussion of nuclear issues, see Note 12 and Note 13 to the Financial Statements under Item 8.

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Electric Operating Statistics (NSP-Minnesota)

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Electric Operating Statistics (NSP-Wisconsin)