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

FORM 10-Q

Commission File No. 33-7591

(An Electric Membership Corporation)
(Exact name of registrant as specified in its charter)

        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 ý    No o

        Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a non-accelerated filer.smaller reporting company. See definitiondefinitions of "accelerated filer" and "large accelerated filer"filer," "accelerated filer," and "smaller reporting company" in Rule 12b-2 of the Exchange Act. (Check one):Large Accelerated Filer o    Accelerated Filer o    Non-Accelerated Filer ý

        Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).Yes o    No ý

        Indicate the number of shares outstanding of each of the registrant's classes of common stock, as of the latest practicable date.The registrant is a membership corporation and has no authorized or outstanding equity securities.

(This page has been left blank intentionally.)

OGLETHORPE POWER CORPORATION
INDEX TO QUARTERLY REPORT ON FORM 10-Q
FOR THE QUARTER ENDED SEPTEMBER 30, 2007MARCH 31, 2008

PART I—FINANCIAL INFORMATION
Item 1. Financial Statements

Oglethorpe Power Corporation
Condensed Balance Sheets (Unaudited)
September 30, 2007March 31, 2008 and December 31, 20062007

The accompanying notes are an integral part of these condensed financial statements.

Oglethorpe Power Corporation
Condensed Balance Sheets (Unaudited)
September 30, 2007March 31, 2008 and December 31, 2006
2007

The accompanying notes are an integral part of these condensed financial statements.

Oglethorpe Power Corporation
Condensed Statements of Revenues and Expenses (Unaudited)
For the Three and Nine Months Ended September 30,March 31, 2008 and 2007 and 2006

The accompanying notes are an integral part of these condensed financial statements.

Oglethorpe Power Corporation
Condensed Statements of Patronage Capital and Membership Fees
and Accumulated Other Comprehensive Deficit (Unaudited)
For the NineThree Months Ended September 30,March 31, 2008 and 2007 and 2006

The accompanying notes are an integral part of these condensed financial statements.

Oglethorpe Power Corporation
Condensed Statements of Cash Flows (Unaudited)
For the NineThree Months Ended September 30,March 31, 2008 and 2007 and 2006

The accompanying notes are an integral part of these condensed financial statements.

Oglethorpe Power Corporation
Notes to Unaudited Condensed Financial Statements
September 30,March 31, 2008 and 2007 and 2006

(A)

General.    The condensed financial statements included in this report have been prepared by Oglethorpe Power Corporation (Oglethorpe), pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). In the opinion of management, the information furnished in this report reflects all adjustments (which include only normal recurring adjustments) and estimates necessary to fairly state, in all material respects, the results for the periods ended September 30, 2007March 31, 2008 and 2006.2007. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles (GAAP) have been condensed or omitted pursuant to SEC rules and regulations, although Oglethorpe believes that the disclosures are adequate to make the information presented not misleading. These condensed financial statements should be read in conjunction with the financial statements and the notes thereto included in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006,2007, as filed with the SEC. The results of operations for the three-month and nine-month periodsperiod ended September 30, 2007March 31, 2008 are not necessarily indicative of results to be expected for the full year. As noted in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006,2007, substantially all of Oglethorpe's sales are to its 38 electric distribution cooperative members (the Members) and, thus, the receivables on the accompanying balance sheets are principally from its Members. (See "Notes to Financial Statements" in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006.2007.)

(B)

Adoption of Financial Interpretation No. 48, "Accounting for Uncertainty in Income Taxes—an Interpretation of Financial Accounting Standards No. 109 Positions" (FIN 48).    In July 2006, the Financial Accounting Standards Board (FASB) issued FIN 48. The interpretation addresses the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the financial statements. Under FIN 48, Oglethorpe may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position should be measured based on the largest benefit that has the greater than fifty percent likelihood of being realized upon ultimate settlement. FIN 48 also provides guidance on derecognition, classification, interest and penalties on income taxes, accounting in interim periods and requires increased disclosures.

Oglethorpe and its subsidiaries file a U.S. federal consolidated income tax return. The U.S. federal statute of limitations remains open for the year 2004 forward. State jurisdictions have statutes of limitations generally ranging from three to five years from the filing of an income tax return. The state impact of any federal changes remains subject to examination by various states for a period of up to one year after formal notification to the states. Years still open to examination by tax authorities in major state jurisdictions include 2004 forward.

Oglethorpe adopted the provisions of FIN 48 effective January 1, 2007. As a result of the adoption of FIN 48, Oglethorpe recognized a $96 million increase in the liability for unrecognized tax benefits. This change in the liability resulted in no decrease to the January 1, 2007 balance of patronage capital as the effects were offset by recognition of deferred tax assets. During the third quarter of 2007, one of the four open years expired. Accordingly, this liability and related deferred tax asset was reduced by $24 million during the third quarter. Oglethorpe is carrying forward significant regular tax and alternative minimum tax (AMT) net operating losses (NOLs). Therefore, any regular tax liability in the open years related to the uncertain tax position would be offset by regular NOLs. However, Oglethorpe would be liable for the portion of AMT for this

period that is not allowed to be offset by the AMT NOLs. In the current open years, Oglethorpe's exposure is not material to its consolidated results of operations, cash flows or financial position.

Oglethorpe recognizes accrued interest with uncertain tax positions in interest expense in the condensed statements of revenues and expenses. As of September 30, 2007, Oglethorpe has recorded approximately $464,450 for interest in the accompanying balance sheet. It is expected that the amount of unrecognized tax benefits will change in the next twelve months; however, Oglethorpe does not expect the change to have a significant impact on its results of operations, its financial position or its effective tax rate.

(C)

New Accounting Standards.    In February 2007, the FASB issued SFAS No. 159, "The Fair Value Option for Financial Assets and Financial Liabilities," including an amendment of SFAS No. 115, "Accounting for Certain Investments in Debt and Equity Securities." This statement permits entities to choose to measure many financial instruments and certain other items at fair value that are not currently required to be measured at fair value. This statement also establishes presentation and disclosure requirements designed to facilitate comparison between entities that choose different measurement attributes for similar types of assets and liabilities. The statement provides entities with the opportunity to mitigate volatility in reported earnings caused by measuring related assets and liabilities differently without having to apply complex hedge accounting provisions. The provisions of this Statement apply only to entities that elect the fair value option; however, the amendment to SFAS No. 115 applies to all entities with available-for-sale and trading securities. SFAS No. 159 is effective for Oglethorpe January 1, 2008; however, Oglethorpe has elected not to adopt the provisions of SFAS No. 159 except for those provisions applicable to SFAS No. 115.

In September 2006, the FASB issued SFASStandard (SFAS) No. 157, "Fair Value Measurements,Measurements." which    On January 1, 2008, Oglethorpe adopted SFAS No. 157. SFAS No. 157 defines fair value, establishes a framework for measuring fair value in generally accepted accounting principles (GAAP),accordance with GAAP, and expands disclosures about fair value measurements. SFAS No. 157 does not require any new fair value measurements. However,In November 2007, the applicationFinancial Accounting Standards Board (FASB) issued a one-year deferral for the implementation of SFAS No. 157 may changefor non-financial assets and non-financial liabilities that are recognized or disclosed at fair value in the current practicefinancial statements on a nonrecurring basis. The deferral is applicable for measuringasset retirement obligations measured at fair value. value upon initial recognition under FASB Statement No. 143, "Accounting for Asset Retirement Obligations", or upon a remeasurement event. The effective date for the implementation of SFAS No. 157 for non-financial assets and non-financial liabilities is January 1, 2009.

SFAS No. 157 is to be applied prospectively as of the first interim period for the fiscal year in which it is initially adopted, except for limited retrospective adoption for the following three items:

•

The valuation of financial instruments using blockage factors;



•

Financial instruments that were measured at fair value using the transaction price (as indicated in Emerging Issues Task Force (EITF) Issue 02-3); and



•

The valuation of hybrid financial instruments that were measured at fair value using the transaction price (as indicated in SFAS No. 155).

The impact of adoption in these areas would be applied as a cumulative-effect adjustment to opening retained earnings, measured as the difference between the carrying amounts and the fair values of relevant assets and liabilities at the date of adoption. Oglethorpe does not have any of the three aforementioned items, therefore no transition adjustment will be recorded.




SFAS No. 157 establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

•

Level 1.  Quoted prices from active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Quoted prices in active markets provide the most reliable evidence of fair value and shall be used to measure fair value whenever available. Level 1 primarily consists of financial instruments that are exchange-traded.



•

Level 2.  Pricing inputs other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date. Level 2 includes financial instruments that are valued using models or other valuation methodologies. These models are primarily industry-standard models that consider various assumptions, including quoted forward prices for commodities, time value, volatility factors, and current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Level 2 primarily consists of financial instruments that are non-exchange-traded but have significant observable inputs.



•

Level 3.  Pricing inputs include significant inputs that are generally less observable from objective sources. These inputs may be used with internally developed methodologies that result in management's best estimate of fair value. Level 3 financial instruments are those whose fair value is based on significant unobservable inputs.

As required by SFAS No. 157, assets and liabilities measured at fair value are based on one or more of the following three valuation techniques:

1.

Market approach.    The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities (including a business) and deriving fair value based on these inputs.



2.

Income approach.    The income approach uses valuation techniques to convert future amounts (for example, cash flows or earnings) to a single present amount (discounted). The measurement is based on the value indicated by current market expectations about those future amounts.



3.

Cost approach.    The cost approach is based on the amount that currently would be required to replace the service capacity of an asset (often referred to as current replacement cost). This approach assumes that the fair value would not exceed what it would cost a market participant to acquire or construct a substitute asset or comparable utility, adjusted for obsolescence.




The tables below detail assets and liabilities measured at fair value on a recurring and non-recurring basis (dollars in thousands).

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Assets and Liabilities Measured on a Recurring Basis


---

					Fair Value Measurements at Reporting Date Using
			March 31, 2008			Quoted Prices in Active Markets for Identical Assets (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Decommissioning funds		$	231,918		$	168,059		$	62,874		$	985
Bond, reserve, and construction funds			4,572			—			4,572			—
Long term investments			98,944			47,760			19			51,165
Restricted short term investments			40,033			—			40,033			—
Natural gas swaps			7,969			—			7,969			—
Deposit on Rocky Mountain transactions			102,981			—			—			102,981
Investments in associated companies			45,217			—			—			45,217

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Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3)


---

				Decommissioning funds			Long-term investments			Deposit on Rocky Mountain transactions			Investments in associated companies
Assets:
Balance at January 1, 2008			$	1,342		$	7,300		$	101,272		$	46,449
Total gains or losses (realized/unrealized):
	Included in earnings			(50	)		—			—			—
	Included in regulatory asset			20			—			—			—
	Impairment included in other comprehensive deficit			—			(2,435	)		—			—
Purchases, issuances, settlements				—			—			—			—
Transfers to Level 3				(327	)		46,300	(1)		1,709			(1,232	)
Balance at March 31, 2008			$	985		$	51,165		$	102,981		$	45,217

Liabilities:				Interest Rate Swaps
Balance at January 1, 2008			$	30,526
Total gains or losses (realized/unrealized):
	Included in other comprehensive deficit			3,245
	Included in regulatory assets and liabilities			(33,771	)
Balance at March 31, 2008			$	—

(1)

Based on market conditions, Oglethorpe changed its valuation technique for auction rate securities to an income approach using a discounted cash flow model. Accordingly, these investments which are included in long-term investments on the condensed balance sheet changed from Level 1 to Level 3 within SFAS No. 157's three-tier fair value hierarchy during the period ending March 31, 2008.



Realized losses included in earnings for the period are reported in other (expense) income.

---


Assets and Liabilities Measured on a Nonrecurring Basis


---

					Fair Value Measurements at Reporting Date Using
			December 31, 2007		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Long-term debt		$	3,503,861		—		—		$	3,503,861

(C)

New Accounting Pronouncement.    In March 2008, the FASB issued SFAS No. 161, "Disclosures about Derivative Instruments and Hedging Activities." The new standard is intended to improve financial reporting about derivative instruments and hedging activities by requiring enhanced disclosures to enable investors to better understand their effects on an entity's financial position, financial performance, and cash flows. The new standard is effective January 1, 2008, and Oglethorpe is evaluating the impact, if any, that2009. Currently, the adoption of SFAS No. 157 will161 is not expected to have any impact on Oglethorpe's financial position or results of operations or financial condition.

.

(D)

Accumulated Comprehensive Deficit.    The table below provides detail of the beginning and ending balance for each classification of accumulated other comprehensive deficit along with the amount of any reclassification adjustments included in margin for each of the periods presented in the StatementCondensed Statements of Patronage Capital and Membership Fees and Accumulated Other Comprehensive Deficit. There were no material changes in the nature, timing or amounts of expected (gain) loss reclassified to net margin from the amounts disclosed in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006.2007. See Note G for further discussion regarding the termination of the interest rate swap arrangements.

Oglethorpe's effective tax rate is zero; therefore, all amounts below are presented net of tax.

---


Accumulated Other Comprehensive Deficit


---

(E)

Environmental MattersMatters.:    Set forth below are environmental matters that could have an effect on Oglethorpe's financial condition or results of operations. At this time, the resolution of these matters is uncertain, and Oglethorpe has made no accruals for such contingencies and cannot reasonably estimate the possible loss or range of loss with respect to these matters.

1.    GeneralGeneral..    As is typical for electric utilities, Oglethorpe is subject to various federal, state and local air and water quality requirements which, among other things, regulate emissions of pollutants, such as particulate matter, sulfur dioxide, and nitrogen oxides and mercury into the air and discharges of other pollutants, including heat, into waters of the United States. Oglethorpe is also subject to federal, state and local waste disposal requirements that regulate the manner of transportation, storage and disposal of various types of waste.

In general, environmental requirements are becoming increasingly stringent. New requirements may substantially increase the cost of electric service by requiring changes in the design or operation of existing facilities or changes or delays in the location, design, construction or operation of new facilities. Failure to comply with these requirements could result in the imposition of civil and criminal penalties as well as the complete shutdown of individual generating units not in compliance. Certain of ourOglethorpe's debt instruments require us to comply in all material respects with laws, rules, regulations and orders imposed by applicable governmental authorities, which include current or future environmental laws and regulations. Should we fail to be in compliance with these requirements, it would constitute a default under such debt instruments. Oglethorpe cannot provide assurance that it will always be in compliance with current and future regulations.

2.    Clean Air Act.    In January 2003, the Sierra Club appealed an unsuccessful challenge to the air operating permit for the Chattahoochee combined cycle facility to the U.S. Court of Appeals for the Eleventh Circuit. Oglethorpe acquired this facility when it merged with Chattahoochee EMC in May 2003. Oglethorpe intervened in the appeal on behalf of the U.S.The Environmental Protection Agency (EPA). In May 2004, the Court ruled announced on March 27, 2008 that, in favor of the Sierra Club, invalidating EPA's denial of the petition and remanding the matter to EPA for further consideration. In November 2005, EPA issued an order denying Sierra Club's petition to objectresponse to the permit. In January 2006,Supreme Court's April 2007 decision in Massachusetts v. EPA, it intends to issue an Advance Notice of Proposed Rulemaking (ANPR) later this spring to consider potential regulation of greenhouse gas emissions from stationary and mobile sources under the Sierra Club filed an appealClean Air Act. Oglethorpe cannot predict at this time whether regulation of that order togreenhouse gas emissions from its power plants will ultimately result from this action and the U.S. Courteffects of Appeals for the Eleventh Circuit. Oglethorpe again intervened in the appeal on behalf of EPA, and on June 26, 2007, the Courtany such regulation.

ruled in favor of EPA, upholding its decision not to object to the permit. The time for Sierra Club to appeal has not yet expired.

In April 2007, the Sierra Club and the Coosa River Basin Initiative appealed two unsuccessful permit challenges involving operating permit renewals for Plants Scherer (co-owned by Oglethorpe), Bowen, Hammond and Branch to the U.S. Court of Appeals for the Eleventh Circuit. The permits were all challenged on the basis of not including compliance schedules to bring the sources into compliance with theapplicable opacity standards, not including an adequate statement of basis, and for Scherer and Bowen, not including compliance schedules to bring the sources into compliance with Prevention of Significant Deterioration requirements. Oglethorpe filed a motion to intervene on behalf of EPA in the case and that motion was granted. Briefing on the case is scheduled to bewas completed in November 2007. OralDecember 2007, and oral argument occurred on March 31, 2008. A decision is expected to be scheduled for Spring 2008, with a decision likely to be reached byfrom the Court later that year.in 2008.

(F)

SalePollution Control Revenue Bonds (PCBs).    The three major credit rating agencies are in the process of SO₂ Allowances.    Duringan on-going review of the nine-month period ended September 30, 2006,monoline bond insurers as a result of the exposure some insurers have to financial guarantees provided on structured finance obligations, primarily those backed by subprime residential mortgages. Several bond insurers have already been downgraded below their historical triple-A rating levels or have had negative outlooks assigned to their triple-A ratings, including three insurers that provide guarantees on a significant portion of Oglethorpe's outstanding variable rate PCB indebtedness.

Bond insurer downgrades have been most material as it relates to their impact on auction rate securities (ARS) guaranteed by the insurer, leading to increased focus on the underlying issuer credit, wider credit spreads, and failed auctions. A bond insurer downgrade can also affect the credit spread of insured variable rate demand bonds (VRDB); however, any effect is generally less

than on ARS due to bank liquidity support on a VRDB which allows bonds to be put to the liquidity facility in the event of a failed remarketing.

On March 31, 2008, Oglethorpe sold SO₂ allowanceshad outstanding $435 million of PCBs in excessthe ARS mode and $410 million of PCBs in the VRDB mode. Oglethorpe has recently seen some of its needsARS auctions fail due to various third partiesinvestors moving away from the ARS market, and received $39.5has also had VRDBs put to the supporting bank liquidity facilities due to the remarketing agents' inability to remarket the bonds as a result of a downgrade of the bond insurer. These events have resulted in higher variable rates of interest on the bonds, in some instances as high as 12.0%. At March 31, 2008, the weighted average interest rate on all of Oglethorpe's outstanding PCB debt was 6.3%.

In light of these events, in two separate remarketings that closed in April 2008, Oglethorpe converted $312 million in net proceedsof its PCBs from these sales; there were no salesthe ARS mode to a Term Rate mode of SO₂ allowances duringinterest as it had the three-month period ended September 30, 2006. The 2006 gainoption to do pursuant to the underlying bond documents. For more information on these sales is reflected in the "Gain on sale of emission allowances" in the accompanying Condensed Statements of Revenuesinterest rate mode conversions, see Oglethorpe's Form 8-K dated April 17, 2008 and Expenses (Unaudited). Sales of SO₂ allowances for the nine-month period ended September 30, 2007 totaled $0.4 million.

Form 8-K dated April 24, 2008.

(G)

Ad Valorem Tax Matters.Interest Rate Swap Transactions.    For each taxAs noted in Oglethorpe's Annual Report on Form 10-K for the fiscal year 2003-2006,ended December 31, 2007, Oglethorpe terminated both the Monroe County BoardAIG Financial Products Corp. (AIG-FP) interest rate swaps and the JPMorgan Chase Bank (JPMC) interest rate swaps in March 2008. Oglethorpe made a termination payment to AIG-FP of Tax Assessors has issued its assessment$36,611,000 and received a termination payment from JPMC of Oglethorpe's interest$2,840,000. The amounts have been recorded as a regulatory asset and regulatory liability in Plant Schereraccordance with SFAS No. 71, "Accounting for an amount greater thanEffects of Certain Types of Regulation" and will be amortized into expense over the value determined by the Georgia Department of Revenue (DOR). Oglethorpe has appealed eachremaining original life of the County's valuations by filing a notice of arbitration with the Monroe County Board of Tax Assessors. The arbitration for all four appeals are on hold pending the outcome of a related case filed by GPC, which challenges the authority of Monroe County to change the values determined by the Georgia Department of Revenue. GPC obtained a ruling from the Georgia Court of Appeals that Monroe County did not have the authority to change the values determined by the Georgia Department of Revenues. However, the Georgia Supreme Court granted the County's request to review that ruling. On October 15, 2007, the parties made their oral arguments. Depending on the final outcome of the GPC appeal, the arbitration for Oglethorpe's four appeals will be heard by a panel of arbitrators, with the right to appeal first to the Monroe County Superior CourtSeries 1993A bonds and then to the Georgia appellate courts. None of the appeals have been sent to the arbitrators, but even if a negative result occurred, Oglethorpe does not believe that it would have a material effect on its financial condition1994A bonds, or results of operations.2016 and 2019, respectively.

Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations

Results of Operations

For the Three Months Ended March 31, 2008 and Nine Months Ended September 30, 2007 and 2006

Forward-Looking Statements and Associated Risks

This Quarterly Report on Form 10-Q contains forward-looking statements, including statements regarding, among other items, (i) anticipated transactions by Oglethorpe, (ii) Oglethorpe's future capital requirements and sources of capital and (iii) achievement of a minimum 1.10 Margins for Interest Ratio (MFI Ratio). These forward-looking statements are based largely on Oglethorpe's current expectations and are subject to a number of risks and uncertainties, some of which are beyond Oglethorpe's control. For factors that could cause actual results to differ materially from those anticipated by these forward-looking statements, see Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006,2007, in particular Item 1A-Risk1A—Risk Factors. In light of these risks and uncertainties, there can be no assurance that events anticipated by the forward-looking statements contained in this Quarterly Report will in fact transpire.

Net Margin

Oglethorpe's net margin (deficit) for the three-month and nine-month periodsperiod ended September 30, 2007March 31, 2008 was $1.1 million and $18.9$6.7 million compared to ($1.3) million and $28.5$9.5 million for the same periodsperiod of 2006.2007. The net margin (deficit) variancesvariance for the three-month and nine-month periodsperiod ended September 30, 2007March 31, 2008 compared to the same periodsperiod of 20062007 was primarily relatedue to budgeted interest on long-term debt and capital leases in 2008 being lower than the gainactual amount. In 2007 the actual amount of interest on sale of SO₂ allowances during the first quarter of 2006 as discussed in Note F of the Notes to Unaudited Condensed Financial Statements. See"Operating Revenues" below for discussion regarding impact of gain on sale of SO₂ allowances on Member capacity revenues.long-term debt and capital leases was slightly lower than budgeted amount.

Throughout the year, Oglethorpe monitors its financial results and, with Board approval, makes budget adjustments when and as necessary to ensure that a net margin equivalent to the minimum 1.10 MFI Ratio required under the Mortgage Indenture is achieved. Oglethorpe's management anticipates that the margin for the year endedending December 31, 20072008 will be approximately $19$19.5 million, which will yield an MFI Ratio of 1.10. For additional information on Oglethorpe's margin requirement, see "Management's Discussion and Analysis of Financial Condition and Results of Operations—"MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS—Summary of Cooperative Operations—Rates and Regulation" in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006.2007.

Operating Revenues

Oglethorpe's operating revenues fluctuate from period to period based on factors including weather and other seasonal factors, load growth in the service territories of its Members, operating costs, availability of electric generation resources, Oglethorpe's decisions of whether to dispatch its owned or purchased resources or Member-owned resources over which it has dispatch rights, and by Members' decisions of whether to purchase a portion of their hourly energy requirements from Oglethorpe's resources or from other suppliers.

Total revenues from sales to Members were 4.6% and 4.7%8.7% higher in the three-month and nine-month periodsperiod ended September 30, 2007March 31, 2008 than such revenues for the same periodsperiod of 2006.2007. Megawatt-hour (MWh) sales to Members increased 2.1%7.8% in the current quarter of 20072008 versus the same quarter of 2006 and decreased 0.5% during the nine months ended September 30, 2007 compared to the same period of 2006.2007. The average total revenue per MWh from sales to Members increased 2.4% and 5.3%0.9% for the three-month and nine-month periodsperiod ended September 30, 2007March 31, 2008 compared to the same periodsperiod of 2006. For the three-months and nine-months ended September 30, 2007 MWhs supplied by2007.

Oglethorpe to its Members varied slightly. There was however, a decrease in MWhs sold to Members primarily due to the termination, effective March 31, 2006, of an agreement to purchase capacity and energy from Georgia Power Company (GPC) at a favorable cost. This decrease was offset somewhat by an increase in MWhs generated and sold to Members. For further discussion regarding purchased power costs and the increase in generation, see "Operating Expenses" below.

The components of Member revenues for the three months ended March 31, 2008 and nine months ended September 30, 2007 and 2006 were as follows (amounts in thousands except for cents per kilowatt hour):

Capacity revenues for the three-month and nine-month periodsperiod ended September 30, 2007 increased 2.9% and 3.9%March 31, 2008 remained relatively constant compared to the same periodsperiod of 2006. Capacity revenues as budgeted and billed for the nine-month period ended September 30, 2007 reflect lower collections of approximately $3.8 million due to the termination of the GPC power purchase agreement effective March 31, 2006. Capacity revenues as budgeted and billed for the nine-month period ended September 30, 2006 reflect lower collections from Members of $20.9 million. Collections from Members were lower in 2006 to offset a portion of the gain on sale of SO₂allowances in 2006.2007. Energy revenues were 6.0% and 5.5%21.3% higher for the three-month and nine-month periodsperiod ended September 30, 2007March 31, 2008 compared to the same periodsperiod of 2006.2007. Oglethorpe's average energy revenue per MWh from sales to Members was 3.8% and 6.0%12.5% higher for the current periodsperiod of 20072008 as compared to the same periodsperiod of 2006.2007. The increase in energy revenues and energy revenues per MWh for the three months and nine months ended September 30, 2007March 31, 2008 was primarily due to an increase in the pass through of higher fuel costs. Forcosts (partly due to higher generation and partly due to the nine-month period ended September 30, 2007change in the increase ingeneration mix) and higher fuel costs was offset somewhat by the pass through of lower purchased power costs.energy costs (primarily due to the higher volume of purchased MWhs). For a discussion of fuel costs and purchased power costs, see "Operating Expenses" below.

Operating Expenses

Operating expenses for the three-month and nine-month periodsperiod ended September 30, 2007 (excluding the gain on the sale of SO₂ allowances of $0.4 million for year-to-date 2007 and $39.5 million forMarch 31, 2008 increased 9.3% compared to the same period of 2006, respectively,) increased 5.2% and 1.5% compared to the same periods of 2006.2007. The increase in operating expenses for the current quarter of 20072008 compared to the same quarter of 20062007 was primarily due to higher fuel costs, production expenses and higher production expenses. The increase in operating expenses forpurchased power costs offset somewhat by lower depreciation and amortization expense.

For the nine-monththree-month period ended September 30, 2007March 31, 2008 compared to the same period of 2006 was primarily due to increases in fuel costs and production expenses offset somewhat by lower purchased power and depreciation expenses.

For the three-month and nine-month periods ended September 30, 2007, compared to the same periods of 2006, total fuel costs increased 7.6% and 13.1%20.9% while total generation increased 2.5% and 1.6%, respectively.7.1%. Average fuel costs per MWh increased 5.0% and 11.3%12.9% in the current periodsperiod of 20072008 compared to the same periodsperiod of 2006.2007. The increase in total and average fuel costs for the three-month and nine-month periodsperiod ended September 30, 2007March 31, 2008 as compared to the same periodsperiod of 20062007 resulted primarily from increased generation of higher cost coal-fired generation at Plant Wansley and from higher cost natural gas-fired generation from both the Chattahoochee energy facilityfacility. Gas-fired and coal-fired generation have a higher average cost per MWh of generation as compared to a lesser degree, from the Talbot energy facility.nuclear generation.

Production costs increased 9.8%9.5% for the three-month period ended September 30, 2007March 31, 2008 compared to the same period of 2006.2007. The increase was primarily due to increased(1) major maintenance outage costs at the Doyle energy facility in 2008 (there were no major maintenance outage costs in the same period of 2007), (2) an increase in security personnel headcount at the nuclear generating facilities as well as hiring of replacement workers for a retiring workforce, and (3) an increase in amortization of deferred nuclear refueling outage costs and increased amortization of deferred operations and maintenance (O&M) outage costs for coal-fired generation plants in 20072008 compared to 2006. The increase in O&M expenses is also partly attributable to higher expenses at Plant Wansley for Selective Catalytic Reduction (SCR) operations. In addition, administrative and general (A&G) expenses increased by 25.7% (or $1.6 million) partly due to timing of expenses incurred from various membership organizations and partly due to increases in administrative support services from Georgia System Operations Company (GSOC), professional services and payroll expenses.2007.

Total purchased power costs decreased 5.0% and 17.0%increased 17.9% for the three-month and nine-month periodsperiod ended September 30, 2007March 31, 2008 compared to the same periodsperiod of 2006.2007. Purchased MWhs decreased 5.5% and 30.0%increased 29.2% for the three months and nine months ended September 30, 2007March 31, 2008 compared to the same periodsperiod of 2006.2007. The average cost per MWh of total purchased power increased 0.6% and 18.5%decreased 8.8% for the three months and nine months ended September 30, 2007March 31, 2008 compared to the same periodsperiod of 2006.2007.

Purchased power costs were as follows:follows (amounts in thousands except for cents per kilowatt hour):

Purchased power capacity costs varied slightlyremained relatively unchanged in the current quarter of 20072008 compared to the same quarter of 2006 and decreased 13.0% for the nine months ended September 30, 2007 as compared to the same period of 2006.2007. Purchased power energy costs for the three-month and nine-month periodsperiod ended September 30, 2007 decreased 6.4% and 18.3% compared to the same periods of 2006. The decrease in purchased power capacity and energy costs for the nine months ended September 30, 2007March 31, 2008 increased 25.6% compared to the same period of 2006 resulted primarily from the decrease in purchased MWhs, which in turn resulted primarily from the termination of the GPC agreement, effective March 31, 2006, as discussed above.2007. The average cost of purchased power energy decreased 1.0% and increased 16.7%2.8% for the three-month and six-month periods ended September 30, 2007 compared to the same periods of 2006. Purchased power energy costs, purchased MWhs and average cost of energy per MWh varied slightly for the current quarter of 2007 compared to the same quarter of 2006. The decrease in purchased power energy costs and volume of purchased power MWhs along with the increase in average energy cost per MWh during the nine-month period ended September 30, 2007March 31, 2008 compared to the same period of 2006 was primarily due to the termination of the GPC purchased power agreement (with its favorable energy cost to Oglethorpe), effective March 31, 2006.2007. The decreaseincrease in MWhs acquired under Oglethorpe's energy replacement program, which replaces power from Oglethorpe owned generation facilities with lower price spot market purchased power energy, also contributed towas primarily responsible for the decreaseincrease in purchased power energy costs and tofor the increase volume of purchased power MWhs.MWhs, along with the corresponding decrease in the average cost per MWh of purchased power energy. In addition, an increase in MWhs acquired under a purchased power agreement with Morgan Stanley also contributed to the increase in purchased power energy costs.

Accretion expense represents the change in theOglethorpe's asset retirement obligations due to the passage of time. For nuclear decommissioning, Oglethorpe records a regulatory asset or liability for the timing difference in accretion recognized under SFAS No. 143, "Accounting for Asset Retirement Obligations", compared to the expense recovered for ratemaking purposes. The accretion expense recognized by Oglethorpe is equal to the lesser of the earnings from both the decommissioning trust fund and the internal

decommissioning fund or the AROasset retirement obligation for nuclear decommissioning expenses to be recognized under FASSFAS No. 143. The earnings on the decommissioning funds in the three-month and nine-month periods ended September 30, 2007first quarter of 2008 were $0.9 million higher and $1.5$2.0 million lower than in the same periodsperiod of 2006.2007. As a result, accretion expense increased 51.4% and decreased 4.9%, respectively, during the three and nine months ended September 30, 2007 as compared to the same periods of 2006.

Depreciation and amortization expense decreased 9.3% (or $11.2 million) for the nine-month period ended September 30, 2007 compared to the same period of 2006. Depreciation and amortization expenses in 2007 were lower primarily because of accelerated amortization of deferred amortization of capital leases taken in 2006 in order to offset a portion of the gain from the 2006 sale of SO₂ allowances. Depreciation and amortization expense remained relatively flat$2.0 million during the three months ended September 30, 2007March 31, 2008 as compared to the same period of 2006.2007.

Depreciation and amortization expense decreased 17.9% (or $6.5 million) for the three-month period ended March 31, 2008 compared to the same period of 2007. Depreciation and amortization expenses in 2008 were lower primarily due to lower depreciation expenses for Plant Vogtle of $7.2 million. In June 2007, Georgia Power Company (GPC), as agent for the co-owners, filed an application with the Nuclear Regulatory Commission (NRC) to extend the licenses for Vogtle Unit No. 1 and Unit No. 2 for an additional 20 years. Effective July 1, 2007, Oglethorpe under the provisions of SFAS No. 71 began deferring the difference between Plant Vogtle depreciation expense based on the current 40-year operating license versus depreciation expense based on the applied for 20-year license extension. The deferral amount will be amortized to depreciation expense over the remaining life of Plant Vogtle beginning in the year the license extension is approved by the NRC. The approval from the NRC is expected mid-2009 or later.

Other Income

Investment income increased 40.0%decreased 34.1% (or $2.7 million) and 11.4% (or $3.3$4.0 million) in the three-month and nine-month periods in 2007period ending March 31, 2008 compared to the same periodsperiod of 2006.2007. The increasedecrease for the three months and nine months ended September 30, 2007March 31, 2008 compared to the same periodsperiod of 20062007 resulted primarilypartly from increaseddecreased interest earnings on cash and cash equivalent investments principallypartly as a result of higher average investment balances. The higher investment balances resulted primarily from cash generated due to the issuance of additional debt as discussed in"Interest Charges" below. The increase to investment income for the nine months ended September 30, 2007 was offset somewhat partly by the elimination of earnings from funds deposited in the Rural Utilities Service (RUS) Cushion of Credit Account and partly from higher

interest rates on those investments in 2007 as compared to 2008. In addition, lower earnings from the decommissioning trust fund in 2008 compared to the same period of 2007 also contributed to the decrease as discussed above. Funds in the Cushion of Credit Account were utilized to pay debt service costs and as of September 30, 2006, there were no remaining deposits invested in the account; therefore, there has not been any additional income relative to these investments in subsequent periods.

Interest Charges

Interest on long-term debt and capital leases increased by 5.0% and 5.1%6.5% in the three months and nine months ended September 30, 2007March 31, 2008 compared to the same periodsperiod of 2006.2007. This increase resulted primarily from negative events in the issuancecapital markets which affected the cost of $300 millionborrowing for Oglethorpe as it relates to PCBs in first mortgage bondsARS mode and PCBs in October 2006;VRDB mode as well as the proceeds are being usedborrowing costs incurred under the AIG-FP and JPMC interest rate swap transactions. For further discussion of the negative events in the capital markets and the early termination of the interest rate swaps, see Note F and G of Notes to fund the installation of environmental controls facilities at Plant Scherer, one of Oglethorpe's coal-fired generating plants, and for general corporate purposes.Unaudited Condensed Financial Statements.

Balance Sheet Analysis as of September 30, 2007March 31, 2008

Assets

Property additions for the ninethree months ended September 30, 2007March 31, 2008 totaled $123.1$89.0 million. Included in this totalThe expenditures were expenditures of approximately $26 million for nuclear fuel and approximately $53 millionprimarily for environmental control projects. The remaining expenditures were primarily forsystems being installed at Oglethorpe's coal-fired generation plants, nuclear fuel, and normal additions and replacements to existing generation facilities.

The $22.1 million increase in nuclear fuel was due primarily to the timing of purchases and increased uranium costs.

Construction work in progress increased by $71.4$33.1 million in the ninethree months ended September 30, 2007,March 31, 2008, primarily due to costs incurred for various replacement and improvement projects (including environmental control)control systems) at existing generation facilities.

The $15.0 million decrease in long-term investments was principally due to a $21.2 million decrease in the holdings of auction rate securities. The funds were primarily re-invested in commercial paper, which is short-term in nature.

Cash and cash equivalents decreased $97.4$186.8 million principally due to payments for property additions, payments to GPC for operation and maintenance costs, the timing of certain principal and interest payments property additions and payments to GPC.interest rate swap termination payments.

Restricted cash and cash equivalents at December 31, 20062007 represented a portion of the proceeds obtained from the October 2007 refinancing of certain indebtedness associated with pollution control bonds (PCBs) in October 2006.PCBs. These proceeds, which were on deposit with a trustee, were subsequently used in the first quarter of 20072008 to pay principal related to the refinanced PCB debt that was called or matured in January 2007.2008.

ReceivablesRestricted short-term investments represent funds deposited into a Rural Utilities Service (RUS) Cushion of Credit Account with the U.S. Treasury. Funds in the account earn interest at a guaranteed rate of 5% per annum, which is more than Oglethorpe is currently earning on its general fund investments. The funds, and any interest earned thereon, can only be applied to future debt service on RUS and RUS-guaranteed Federal Financing Bank notes.

During the first quarter of 2008, receivables increased $31.3 million, or 34.2%51.7%. The increase was due in part to an increase of approximately $13.3 million in energy revenue (September 2007 vs. December 2006), which was largely a result of increased generation at the natural gas fired plants. In addition, the December 31, 20062007 receivables balance included approximately $10.1$46.7 million of creditscredit available to the Members for a Board approved reduction to 20062007 revenue requirements. TheseThe increase in receivables was largely due to approximately $24.2 million of these credits werebeing realized by the Members during the first quarter of 2007.2008. The increase was also partially due to an additional $16.5 million receivable from GPC being recorded during the first quarter of 2008, which was primarily for the amount of estimated payments made for certain plant capital expenditures that exceeded the amounts incurred. Partially offsetting the increase in receivables was a $7.7 million increase in the contra receivable associated with the unrealized gain on natural gas hedges.

The $6.2 million increase in prepayments and other current assets was primarily the result of a $7.7 million increase in the asset associated with the unrealized gain on natural gas hedges. The

unrealized gain increased as a result of an increase in the mark to market prices. Partially offsetting this increase was the amortization of prepaid insurance balances.

Deferred outage costs increased $4.5$8.5 million (net of amortization), or 17.6%28.4%, as a result of the deferral of approximately $9.0$9.9 million of refueling outage costs incurred at Plant Hatch Unit No. 21 and $11.3$5.8 million at Plant Vogtle Unit No. 21 during the ninethree months ended September 30, 2007.March 31, 2008. In addition, approximately $1.9$1.6 million was deferred for scheduled major maintenance costs at Plant Wansley Unit No. 1 and $5.6 million at Plant Scherer Unit No. 2. Deferred outage costs are amortized over the plant's operating cycle.

As a result of the adoptiontermination of FIN 48,AIG-FP interest rate swaps during the quarter ended March 31, 2008, Oglethorpe has reversed the valuation allowance ofrecorded a $72$36.6 million deferred taxregulatory asset. For further discussion regarding the deferred tax assetinterest rate swap terminations, see Note BG of the Notes to Unaudited Condensed Financial Statements.

The increase in the deferred asset associated with retirement obligations is primarily due to a $13.4 million decrease in the unrealized gain associated with the nuclear decommissioning fund and the corresponding increase in the deferred charge (a $5.6 million deferred credit existed at December 31, 2007). Consistent with Oglethorpe's ratemaking policy, unrealized gains or losses from the nuclear decommissioning fund are added to or deducted from the deferred asset retirement obligation assets or credits. The deferred asset or credit also increases or decreases to the extent of timing differences between accretion expense recognized under SFAS No. 143 and amounts recovered through ratemaking policy (via decommissioning fund earnings). Earnings on the decommissioning fund were approximately $1.3 million less than the related accretion expense, which resulted in the deferred charge also being increased by this amount. For further discussion regarding accretion expense, see "Operating Expenses" above.

Deferred depreciation expense represents amounts being deferred in relation to the application made to the NRC to extend the licenses for Vogtle Unit No. 1 and Unit No. 2 for an additional 20 years. For further discussion regarding this deferral of depreciation expense, see "Operating Expenses" above.

Other deferred charges increased $2.4decreased $4.9 million primarily due to a $1.9$3.0 million increasedecrease in equipment prepayments to GPC. These prepayments are associated with refueling outages at Plant Hatch and Plant Vogtle. The decrease was also partially due to the termination of the JPMC interest rate swaps. For further discussion regarding the interest rate swap terminations, see Note G of the Notes to Unaudited Condensed Financial Statements.

Equity and Liabilities

Primarily as a result of the termination payment made to settle the AIG-FP interest rate swaps, accumulated other comprehensive deficit decreased by $30.3 million. For further discussion regarding the accumulated other comprehensive deficit and the interest rate swap terminations, see Notes D and G of the Notes to Unaudited Condensed Financial Statements.

Long-term debt and capital leases due within one year decreased 52.2%23.3%, or $122.4$33.4 million. The decrease was primarily a result of the reclassification of certain Federal Financing Bank (FFB) and Pollution Control Bond (PCB)PCB debt to long-term debt. The reclassification was duepayments made in partJanuary 2008. In addition to the maturity extensionnormal PCB current maturities, the December 31, 2007 balance included approximately $30.1 million for PCB debt that was redeemed early. The March 31, 2008 balance for PCB debt included only the normal scheduled current maturities.

Accounts payable decreased 39.8%, or $16.6 million, primarily as a result of $428a $16.8 million of certain FFB debtdecrease in May 2007. In October 2007, Oglethorpe also refinanced $454 million of certain FFB debtthe payable to GPC for operation, maintenance and $182 million of certain PCB debt.capital costs. The short-term portionspayable to GPC includes true-up amounts for current and prior month expenditures. The true-up amounts vary to the extent that actual expenditures are different from GPC's estimates of these debtscosts. At March 31, 2008, payments made for costs at certain plants exceeded the estimates and these true-up amounts were also reclassified to long-term debt in accordance with SFAS No. 6, "Classification of Short-term Obligations Expected to be Refinanced". For further discussion regarding the extension of the FFB debt maturities and FFB debt prepayment, see "Financings" below.

The decrease in accrued interest was largely due to the timing ofrecorded as a principal and interest payment for the Plant Scherer Unit No. 2 capital lease obligation. The December 31, 2006 accrued interest balance included an amount for the semi-annual lease payment that was due on January 2, 2007, while the balance at September 30, 2007 included only three months of accrued interest.receivable from GPC.

As a result of a $5.5$13.4 million increasedecrease in the unrealized gain associated with the nuclear decommissioning fund, and an additional $1.3 million of accretion expense recorded as a result of decommissioning fund earnings, the deferred liability associated with asset retirement obligations increasedconverted to a deferred charge and was recorded as an asset.

The liability associated with the interest rate swap arrangements was settled by $7.3 million. For further discussion regarding accretion expense, see "Operating Expenses" above.

As a result of the adoption of FIN 48, Oglethorpe has recorded a $72 million long-term contingent tax liability.payment made to terminate the AIG-FP interest rate swap. For further discussion regarding the long-term contingent tax liabilityinterest rate swap terminations, see Note BG of the Notes to Unaudited Condensed Financial Statements.

Other deferred credits and liabilities increased primarily due to a $4.5 million increase in liabilities associated with payments made to Oglethorpe by its Members. Approximately $2.2 million of the

increase is associated with funding the future overhaul of the combustion turbine plants. An additional $2.3 million is associated with the funding of future debt payments.

Financial Condition

Capital Requirements and Liquidity and Sources of Capital

Environmental Capital Requirements

Oglethorpe's future capital expenditures depend in part on future environmental regulations, including future implementation of existing laws and regulations and how Oglethorpe and the other co-owners of coal-fired Plants Scherer and Wansley choose to comply with these regulations once finalized. Regulations recently adopted by the Georgia Environmental Protection Division specify certain environmental control equipment that must be added to Georgia electric generating units and by specific dates, including Plants Scherer and Wansley. As described in "MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS—Financial Condition—Capital Requirements" in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006,2007, Oglethorpe forecastedforecasts expenditures of $252$900 million forin the period 2008 through 2014 to complete environmental compliance in 2007-2009. Oglethorpe also reported the likelihood of being required to spend $400 million to $600 million beyond 2009, in anticipation of finalization of regulations.projects underway at Plants Scherer and Wansley. As regulations are finalized and design work has continuedcontinues to determine how best to retrofit the units with the required equipment, and as the construction environment, is now being evaluated,including the rising cost of material and labor, continues to evolve, the estimated cost to install these retrofits continues to be being refined. Current indications are that the capital expenditures required beyond 2009 will exceed $600 million, maybe by as much as $200 million to $300 million. Large construction projects such as these entail certain risks, as described in Item 1A1A—Risk Factors of Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006. There2007. These forecasted expenditures are based on information available to Oglethorpe on the date of this Quarterly Report on Form 10-Q; however, there can be no assurance that the cost of compliance with these regulations will not be higher, nor that future regulations will not require additional reductions in emissions or earlier compliance. See Note E of the Notes to Unaudited Condensed Financial Statements for more information on environmental compliance matters.

Liquidity

As of September 30, 2007,March 31, 2008, Oglethorpe had $876$654 million of unrestricted available liquidity to meet short-term cash needs and liquidity requirements. This liquidity consisted of (i) approximately $326$104 million in cash and cash equivalents, and (ii) $550 million available under three committed working capital line of credit facilities.

Oglethorpe has in place a five-year $450 million committed working capital line of credit supporting its commercial paper program that matures in July 2012. The line of credit contains a financial covenant requiring Oglethorpe to maintain patronage capital of at least $400 million, and at September 30, 2007,March 31, 2008, Oglethorpe had patronage capital in excess of $516$523 million. The facility also contains an additional covenant limiting Oglethorpe's secured indebtedness to no more than $8.5 billion and its unsecured indebtedness to no more than $4.0 billion. Oglethorpe's current debt levels are well below these thresholds.

Oglethorpe also has in place two $50 million committed lines of credit, one with National Rural Utilities Cooperative Finance Corporation ("CFC")(CFC) that matures in October 2008, and one with CoBank, ACB that matures in November 2008. Oglethorpe expects to renew the CFC and CoBank credit

facilities as needed, prior to their respective expiration dates.

There are currently no amounts outstanding under anyeither the CFC or CoBank credit facilities.

In April and May 2008, Oglethorpe issued a total of approximately $260 million of commercial paper and used the proceeds to redeem the Series 1993A and Series 1994A PCBs, whose interest cost had increased due to a downgrade of the three committed credit facilitiesbond insurer. Oglethorpe expects to repay this commercial paper in July 2008 using the proceeds from the issuance of the Series 2008 refunding bonds. See "Financings" below for a more detailed discussion of the Series 1993A and Series 1994A redemptions and the related refinancing of these bonds.

In addition to the unrestricted available liquidity discussed above.

above, Oglethorpe also had $40approximately $51 million invested in auction rate securitiesARS at September 30, 2007.March 31, 2008. These securities have maturities in excess of one year and as such are classified as long-term investments. However, most of these securities re-price in auctions that occur every 35 days or less, and Oglethorpe couldcan seek to liquidate these securities at the end of any auction period. Recently, however, there have been failed auctions on the auction rate investments held by Oglethorpe, requiring Oglethorpe to hold the investments during the subsequent auction period. Oglethorpe is currently liquidating these investments when possible. See "Negative Events in the Capital Markets" in Oglethorpe's Annual Report on Form 10-K for the year ended December 31, 2007 for a more detailed discussion of current events causing failed auctions.

Financings

Oglethorpe has embarked on a program to refinance or otherwise reamortize a portion of its FFBFederal Financing Bank and PCB debt to extend the maturities of this debt in connection with the extension, in 2005, of its Member wholesale power contracts from 2025 to 2050. In connection withThis program will be completed later this program, on October 3, 2007 Oglethorpe issued $500,000,000 of Series 2007 First Mortgage Bonds, the proceeds of which were used to prepay approximately $450 million of existing FFB debt and for other general purposes. This new fixed rate debt is subject to mandatory sinking fund redemptions occurring in 2024 to 2030, with a final maturity in 2031.

Alsoyear in connection with a Series 2008 PCB refinancing, totaling approximately $220 million, which Oglethorpe anticipates closing in October. There are several aspects to this financing transaction, including: i) the debt reamortization program, on October 25, 2007 Oglethorpe issued $182refinancing of $10 million of Series 2007PCB principal maturing January 1, 2009 and an extension of the maturities on this debt, ii) the refinancing of the remaining $123 million of PCBs in the ARS mode and an extension of the maturities on this debt, and iii) issuing approximately $85 million in new tax-exempt debt. The new tax-exempt debt is part of $150 million in new tax-exempt financing allocations received in 2005 and 2006 for costs related to qualifying solid-waste equipment in connection with environmental compliance projects underway at Plants Scherer and Wansley. This PCB debt which was used to refinance a like amount of existing PCB debt, including $22 million scheduled to mature on January 1, 2008, $122 million scheduled to mature on January 1, 2018 and $38 million scheduled to mature on January 1, 2024. This $182 million of new variable rate PCB debt has bullet maturities that come due in the 2038 to 2040 time frame. The debt waswill be secured under the Mortgage Indenture. Georgia Transmission Corporation (GTC) elected

In order to participatereduce the interest rate that Oglethorpe was paying on $255 million of outstanding PCBs due to a downgrade of the existing bond insurer, in this refundingApril and assumed an obligationMay of 2008 Oglethorpe issued commercial paper and used the proceeds to redeem the Series 1993A and Series 1994A bonds. Oglethorpe expects to pay $3.7off the commercial paper through the issuance of $255 million of Series 2008 refunding bonds in July 2008. While this transaction is being undertaken mainly to replace the Burke Series 2007A debt. See "MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS—Financial Condition—Off-Balance Sheet Arrangements—GTC Debt Assumption"downgraded bond insurer with a triple-A rated bond insurer, this transaction will also provide for an immediate extension of the maturities, rather than over time as the principal of the 1993A and 1994A bonds was scheduled to mature in Oglethorpe's Annual ReportJanuary of each year through 2016 and 2019, respectively. The PCB debt will be secured under the Mortgage Indenture.

In 2006, Oglethorpe received an allocation from the Internal Revenue Service (IRS) to issue $24 million of Clean Renewable Energy Bonds (CREBs) to fund an upgrade project currently underway at its Rocky Mountain generating facility. CREBs are zero coupon bonds, and in lieu of receiving an interest payment from the issuer the bondholder receives a credit against federal income tax liability. Oglethorpe had its CREB application submitted to the IRS on Form 10-Kits behalf by CFC, along with the applications of other electric cooperatives. CFC, as a qualified issuer under the program, will issue the bonds and in turn loan the proceeds at a low rate of interest (approximately one percent) to the cooperatives whose applications were approved. Unless federal authority for CREBs is expanded,

the fiscal year endedbonds must be issued by December 31, 2006.

In September 2007, the RUS approved a $442 million2008. Oglethorpe anticipates closing its CREBs related loan for Oglethorpe representing two outstanding loan applications that were pending. Oglethorpe does not anticipate closing on this loan and advancing any funds thereunder until mid-2008.with CFC later in 2008.

For more detailed information regarding Oglethorpe's financing plans, see "MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS—Financial Condition—Financing Activities" in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006.2007.

CriticalNewly Adopted or Issued Accounting PolicyStandards

Oglethorpe's critical accounting policies have not changed from the policy reported in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended Dec. 31, 2006 except for the estimate recorded in conjunction with the adoptionFor a discussion of FIN 48. See NoteSFAS No. 157 and SFAS No. 161, see Notes B and C of the Notes to Unaudited Condensed Financial Statements, for further discussion.respectively.

New Accounting Interpretation and Standards

For discussion of FIN 48 and SFAS No. 159 and 157 see Notes B and C of the Notes to Unaudited Condensed Financial Statements.

Item 3. Quantitative and Qualitative Disclosures About Market Risk

Oglethorpe's market risks have not changed materially from the risks reported in Oglethorpe's Annual Report on Form 10-K for the fiscal year ended Dec.December 31, 2006.2007.

Item 4. Controls and Procedures

As of September 30, 2007,March 31, 2008, Oglethorpe had carried out an evaluation, under the supervision and with the participation of its management, including its President and Chief Executive Officer and Chief Financial Officer, of the effectiveness of the design and operation of its disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended). Based on this evaluation, the President and Chief Executive Officer and the Chief Financial Officer concluded that Oglethorpe's disclosure controls and procedures are effective.

There have been no changes in Oglethorpe's internal control over financial reporting or other factors that occurred during the quarter ended September 30, 2007March 31, 2008 that have materially affected, or are reasonably likely to materially affect, Oglethorpe's internal control over financial reporting.

PART II — II—OTHER INFORMATION

Item 1. Legal Proceedings

Environmental Matters

For information about legal and regulatory proceedings regarding environmental matters that could have an effect on Oglethorpe, see Note E of the Notes to Unaudited Condensed Financial Statements.

Item 1A. Risk Factors

There have not been any material changes in Oglethorpe's risk factors from those disclosed in Item 1A of Oglethorpe's Annual Report on Form 10-K for the fiscal year ended December 31, 2006.2007.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

Not Applicable.

Item 3. Defaults upon Senior Securities

Not Applicable.

Item 4. Submission of Matters to a Vote of Security Holders

Not Applicable.

Item 5. Other Information

Not Applicable.In its Annual Report on Form 10-K for the fiscal year ended December 31, 2007, Oglethorpe reported that it was participating in 30% of the cost of the license applications and other development activities for two additional nuclear units at Plant Vogtle, where it owns 30% of the two existing nuclear units. In August 2006, Southern Nuclear Operating Company, on behalf of GPC and the other potential co-owners, filed an application to the NRC for early site permits for these two additional units, and in March 2008 filed an application for combined construction permits and operating licenses for two 1100 MW units, using the Westinghouse AP1000 technology. The proposed commercial operation dates are 2016 and 2017. On April 8, 2008, GPC, for itself and as agent for the other potential co-owners (the Owners), signed an Engineering, Procurement and Construction (EPC) Contract with Westinghouse Electric Company, LLC, and Stone & Webster, Inc., (the Consortium). Pursuant to the EPC Contract, the Consortium would supply and construct the entire facility with the exception of certain owner-supplied items. Under the EPC Contract, the Owners will pay a purchase price that would be subject to certain price escalation and adjustments, adjustments for change orders and performance bonuses. Each Owner is severally (not jointly) liable to the Consortium based on its ownership share. On May 1, 2008, GPC submitted its self-build nuclear proposal in connection with its request for proposals for baseload capacity. No one else submitted a proposal. GPC will submit its final recommendation to the Georgia Public Service Commission (PSC) for certification on August 1, 2008.

Under the terms of a development agreement with GPC and the other potential co-owners, Oglethorpe may reduce its initial ownership interest prior to July 2, 2008 and be refunded a pro rata share of amounts paid, with interest. Oglethorpe will also have limited opportunities during the PSC certification process to reduce its ownership percentage, albeit without getting a refund for amounts paid to date. If Oglethorpe remains as a 30% participant, its estimated total costs, including financing costs, would be approximately $4.2 billion. In December 2006, Oglethorpe submitted a $1.8 billion loan application to RUS covering its potential 30% share in these proposed two nuclear units, which was based on a preliminary cost estimate. In addition to RUS financing, Oglethorpe is evaluating other

sources of financing for this project, including the issuance of tax-exempt bonds for any equipment that may qualify for such financing.

Item 6. Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.