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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 10-Q

QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended March 31, 2015

Commission File Number: 001-33480

CLEAN ENERGY FUELS CORP.

(Exact name of registrant as specified in its charter)

4675 MacArthur Court, Suite 800, Newport Beach, CA 92660

(Address of principal executive offices, including zip code)

(949) 437-1000

(Registrant’s telephone number, including area code)

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 o

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232,405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes x No o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer,” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

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

As of May 4, 2015, there were 90,516,106 shares of the registrant’s common stock, par value $0.0001 per share, issued and outstanding.

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CLEAN ENERGY FUELS CORP. AND SUBSIDIARIES

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PART I.—FINANCIAL INFORMATION

Item 1.—Financial Statements (Unaudited).

Clean Energy Fuels Corp. and Subsidiaries

Condensed Consolidated Balance Sheets

December 31, 2014 and March 31, 2015

(Unaudited)

(In thousands, except share data)

See accompanying notes to condensed consolidated financial statements.

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Clean Energy Fuels Corp. and Subsidiaries

Condensed Consolidated Statements of Operations

For the Three Months Ended March 31, 2014 and 2015

(Unaudited)

(In thousands, except share and per share data)

See accompanying notes to condensed consolidated financial statements.

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Clean Energy Fuels Corp. and Subsidiaries

Condensed Consolidated Statements of Comprehensive Loss

For the Three Months Ended March 31, 2014 and 2015

(Unaudited)

(In thousands)

See accompanying notes to condensed consolidated financial statements.

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Clean Energy Fuels Corp.

Condensed Consolidated Statements of Cash Flows

For the Three Months Ended March 31, 2014 and 2015

(Unaudited)

(In thousands)

See accompanying notes to condensed consolidated financial statements.

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Clean Energy Fuels Corp. and Subsidiaries

Notes to Condensed Consolidated Financial Statements

(Unaudited)

(In thousands, except share and per share data)

Note 1—General

Nature of Business:  Clean Energy Fuels Corp., together with its majority and wholly owned subsidiaries (hereinafter collectively referred to as the “Company,” unless the context of the use of the term indicates otherwise) is engaged in the business of selling natural gas fueling solutions to its customers, primarily in the United States and Canada.

The Company designs, builds, operates and maintains fueling stations and supplies customers with compressed natural gas (“CNG”) fuel for light, medium and heavy-duty vehicles and liquefied natural gas (“LNG”) fuel for medium and heavy-duty vehicles. The Company also manufactures, sells and services non-lubricated natural gas fueling compressors and other equipment used in CNG stations and LNG stations, provides operation and maintenance (“O&M”) services to customers, offers assessment, design and modification solutions to provide operators with code-compliant service and maintenance facilities for natural gas vehicle fleets, transports and sells CNG to large industrial and institutional energy users who do not have direct access to natural gas pipelines, processes and sells renewable natural gas (“RNG”), which can be used as vehicle fuel or sold for renewable power generation, sells tradable credits generated by selling natural gas and RNG as a vehicle fuel, including credits generated under the California Low Carbon Fuel Standard (“LCFS Credits”) and Renewable Identification Numbers (“RIN Credits” or “RINs”) generated under the federal Renewable Fuel Standard Phase 2, helps customers acquire and finance natural gas vehicles and obtains local, state and federal grants and incentives.

Basis of Presentation:  The accompanying interim unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiaries, and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to state fairly the Company’s financial position, results of operations and cash flows as of and for the three months ended March 31, 2014 and 2015. All intercompany accounts and transactions have been eliminated in consolidation. The three month periods ended March 31, 2014 and 2015 are not necessarily indicative of the results to be expected for the year ending December 31, 2015 or for any other interim period or for any future year.

Certain information and disclosures normally included in the notes to the financial statements have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”), but the resultant disclosures contained herein are in accordance with accounting principles generally accepted in the United States of America (“US GAAP”) as they apply to interim reporting. The condensed consolidated financial statements should be read in conjunction with the consolidated financial statements as of and for the year ended December 31, 2014 that are included in the Company’s Annual Report on Form 10-K filed with the SEC on February 26, 2015.

Use of Estimates:  The preparation of condensed consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and revenues and expenses recorded during the reporting period. Actual results could differ from those estimates. Significant estimates made in preparing the condensed consolidated financial statements include (but are not limited to) those related to revenue recognition, warranty reserves, goodwill and long-lived intangible asset valuations and impairment assessments, income tax valuations, and stock-based compensation expense.

Note 2—Acquisition and Divestiture

NG Advantage

On October 14, 2014, the Company entered a Common Unit Purchase Agreement (“UPA”) with NG Advantage, LLC (“NG Advantage”). NG Advantage is engaged in the business of transporting CNG in high-capacity trailers to large industrial and institutional energy users, such as hospitals, food processors, manufacturers and paper mills, which do not have direct access to natural gas pipelines. The Company viewed the acquisition as a strategic investment in the expansion of the Company’s initiative to deliver natural gas to industrial and institutional energy users. Under the terms of the UPA, the Company paid NG Advantage $37,650 for a 53.3% controlling interest in NG Advantage. $19,000 of the purchase price was paid in cash on October 14, 2014 and the remaining $18,650 of the purchase price was paid in the form of an unsecured promissory note issued by the Company (the “NG Advantage Note”). The principal amount of the NG Advantage Note was payable by the Company in two payments as follows: (i) $3,000 was paid January 13, 2015 and (ii) the remaining $15,650 was paid April 1, 2015. The NG Advantage Note did not bear interest. The fair value of the NG Advantage Note delivered to NG Advantage is excluded from the Company’s consolidated statements of cash flows as it is a non-cash investing activity. The consideration paid is accounted for as an intercompany transaction, as NG Advantage’s financial results are included in the Company’s condensed consolidated financial statements.

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The Company accounted for this acquisition in accordance with Financial Accounting Standards Board (“FASB”) authoritative guidance for business combinations, which requires the Company to recognize the assets acquired and the liabilities assumed, measured at their fair values, as of the date of acquisition. The following table summarizes the allocation of the aggregate purchase price to the preliminary fair value of the assets acquired and liabilities assumed:

In connection with its purchase of a controlling interest in NG Advantage, the Company assumed debt of $20,439 on a consolidated basis related to purchases of capital assets and working capital needs. Immediately after the Company’s purchase of the controlling interest, $10,361 of such debt was paid with proceeds of the Company’s investment in NG Advantage, and the related debt instruments were cancelled.

Management allocated approximately $5,600 of the purchase price to the identifiable intangible assets related to customer relationships and trade names that were acquired with the acquisition. The fair value of the identifiable intangible assets will be amortized on a straight-line basis over the estimated useful lives of such assets ranging from four to seven years. The excess of the purchase price over the fair value of net assets acquired was allocated to goodwill, which primarily represents additional market share available to the Company as a result of the acquisition, and is fully deductible for income tax purposes.

Management determined the fair value of the non-controlling interest to be $28,075 using a market approach and using inputs that included use of a comparable transaction to calculate the value of the non-controlling interest adjusted for a control premium.

The results of NG Advantage’s operations have been included in the Company’s consolidated financial statements since October 14, 2014. The historical results of NG Advantage’s operations were not material to the Company’s financial position or historical results of operations.

DCE and DCEMB

On September 4, 2014, Mavrix, LLC (“Mavrix”), a wholly owned subsidiary of the Company, sold to Cambrian Energy McCommas Bluff III LLC (“Cambrian”) 19% of its then-70% interest in Dallas Clean Energy, LLC (“DCE”). On December 29, 2014, Mavrix entered into a Membership Interest Purchase Agreement (the “Agreement”) with Cambrian, pursuant to which Mavrix sold to Cambrian its entire remaining 51% interest in DCE. DCE owns all of the equity interests in Dallas Clean Energy McCommas Bluff, LLC (“DCEMB”), which owns a renewable natural gas extraction and processing project at the McCommas Bluff landfill in Dallas, Texas. As consideration for the sale of DCE, the Company, through Mavrix, received $6,992 in cash in September 2014 and $40,588 in cash in December 2014 and may receive up to an additional $3,000 in cash on or before August 14, 2015, subject to the results of certain performance tests to be performed at the McCommas Bluff project on or before August 1, 2015 in accordance the terms of the Agreement. Prior to December 29, 2014, Cambrian owned a 49% interest in DCE. The Company will continue to have the right to market and sell biomethane produced at the McCommas Bluff project under its Redeem™ renewable natural gas vehicle fuel brand. The transaction resulted in a gain of $11,998 that was recorded in the line item gain from the sale of subsidiary in the Company’s consolidated statement of operations for the year ended December 31, 2014. Included in the determination of the gain was goodwill of $7,205 that was allocated to the transaction in accordance with FASB authoritative guidance for subsequent measure of goodwill which requires the Company to allocate goodwill to the disposed business based on the relative fair values of the business disposed and the portion of the reporting unit that was retained.

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The Company determined, in accordance with FASB authoritative guidance, that the disposal did not meet the definition of a discontinued operation as the disposal did not represent a significant disposal nor was the disposal a strategic shift in the Company’s strategy.

Note 3—Cash and Cash Equivalents

The Company considers all highly liquid investments with maturities of three months or less on the date of acquisition to be cash equivalents. The Company places its cash and cash equivalents with high credit quality financial institutions. At times, such investments may be in excess of the Federal Deposit Insurance Corporation (“FDIC”), Canadian Deposit Insurance Corporation (“CDIC”), and other foreign insurance limits. Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash deposits. The amounts in excess of FDIC, CDIC, and other foreign insurance limits were approximately $103,912 and $88,740 as of March 31, 2015 and December 31, 2014, respectively.

Note 4—Restricted Cash

The Company classifies restricted cash as short-term and a current asset if the cash is expected to be used in operations within a year or to acquire a current asset. Otherwise, the restricted cash is classified as long-term. Restricted cash consisted of the following as of December 31, 2014 and March 31, 2015:

Note 5—Investments

Available-for-sale investments are carried at fair value, inclusive of unrealized gains and losses. Net unrealized gains and losses are included in other comprehensive income (loss) net of applicable income taxes. Gains or losses on sales of available-for-sale investments are recognized on the specific identification basis. All of the Company’s short-term investments are classified as available-for-sale securities.

The Company reviews available-for-sale investments for other-than-temporary declines in fair value below their cost basis each quarter, and whenever events or changes in circumstances indicate that the cost basis of an asset may not be recoverable. This evaluation is based on a number of factors, including the length of time and the extent to which the fair value has been below its cost basis and adverse conditions related specifically to the security, including any changes to the credit rating of the security. As of March 31, 2015, the Company believes its carrying values for its available-for-sale investments are properly recorded.

Short-term investments as of December 31, 2014 are summarized as follows:

Short-term investments as of March 31, 2015 are summarized as follows:

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Note 6—Other Receivables

Other receivables at December 31, 2014 and March 31, 2015 consisted of the following:

Note 7—Inventories

Inventory consists of work in process and finished goods and is stated at the lower of cost (first-in, first-out) or market. The Company writes down the carrying value of its inventory to net realizable value for estimated obsolescence or unmarketable inventory in an amount equal to the difference between the cost of inventory and its estimated realizable value based upon assumptions about future demand and market conditions, among other factors.

Inventories consisted of the following as of December 31, 2014 and March 31, 2015:

Note 8—Land, Property and Equipment

Land, property and equipment at December 31, 2014 and March 31, 2015 are summarized as follows:

Included in land, property and equipment are capitalized software costs of $21,004 and $20,989 as of December 31, 2014 and March 31, 2015, respectively. The accumulated amortization on the capitalized software costs is $10,740 and $11,456 as of December 31, 2014 and March 31, 2015, respectively. The Company recorded $768 and $716 of amortization expense related to the capitalized software costs during the three months ended March 31, 2014 and March 31, 2015, respectively.

As of March 31, 2014 and March 31, 2015, $13,285 and $13,771 are included in accounts payable and accrued liabilities balances, respectively, which amounts are related to purchases of property and equipment. In addition, during the three months ended March 31, 2015, the Company purchased $5,388 of equipment using direct financing. These amounts are excluded from the condensed consolidated statements of cash flows as they are non-cash investing activities.

Note 9—Investments in Other Entities

On September 16, 2014, the Company formed a joint venture with Mansfield Ventures LLC (“Mansfield”) called Mansfield Clean Energy Partners LLC (“MCEP”) , which is designed to provide natural gas fueling solutions to bulk fuel haulers in the U.S. The Company and Mansfield each have a 50% ownership interest in MCEP. The Company accounts for its interest using the equity method of accounting, as the Company has the ability to exercise significant influence over MCEP’s operations. The Company recorded a loss from this investment of $204 for the three months ended March 31, 2015, and has an investment balance of $5,306 at March 31, 2015.

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Note 10—Accrued Liabilities

Accrued liabilities at December 31, 2014 and March 31, 2015 consisted of the following:

Note 11—Warranty Liability

The Company records warranty liabilities at the time of sale for the estimated costs that may be incurred under its standard warranty. Changes in the warranty liability are presented in the following table:

Note 12—Long-Term Debt

7.5% Notes

On July 11, 2011, the Company entered into a loan agreement (the “CHK Agreement”) with Chesapeake NG Ventures Corporation (“Chesapeake”), an indirect wholly owned subsidiary of Chesapeake Energy Corporation, whereby Chesapeake agreed to purchase from the Company up to $150,000 of debt securities (the “CHK Financing”) pursuant to the issuance of three convertible promissory notes, each having a principal amount of $50,000 (each a “CHK Note” and collectively the “CHK Notes” and, together with the CHK Agreement and other transaction documents, the “CHK Loan Documents”). The first CHK Note was issued on July 11, 2011 and the second CHK Note was issued on July 10, 2012.

On June 14, 2013 (the “Transfer Date”), Boone Pickens and Green Energy Investment Holdings, LLC, an affiliate of Leonard Green & Partners, L.P. (collectively, the “Buyers”), and Chesapeake entered into a note purchase agreement (“Note Purchase Agreement”) pursuant to which Chesapeake sold the outstanding CHK Notes (the “Sale”) to the Buyers. Chesapeake assigned to the Buyers all of its right, title and interest under the CHK Loan Documents (the “Assignment”), and each Buyer severally assumed all of the obligations of Chesapeake under the CHK Loan Documents arising after the Sale and the Assignment including, without limitation, the obligation to advance an additional $50,000 to the Company in June 2013 (the “Assumption”). The Company also entered into the Note Purchase Agreement for the purpose of consenting to the Sale, the Assignment and the Assumption.

Contemporaneously with the execution of the Note Purchase Agreement, the Company entered into a loan agreement with each Buyer (collectively, the “Amended Agreements”). The Amended Agreements have the same terms as the CHK Agreement, other than changes to reflect the change in ownership of the CHK Notes. Immediately following execution of the Amended Agreements, the Buyers delivered $50,000 to the Company in satisfaction of the funding requirement they had assumed from Chesapeake (the “June Advance”). In addition, the Company cancelled the existing CHK Notes and re-issued replacement notes, and the Company also issued notes to the Buyers in exchange for the June Advance (the re-issued replacement notes and the notes issued in exchange for the June Advance are referred to herein as the “7.5% Notes”).

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The 7.5% Notes have the same terms as the original CHK Notes, other than the changes to reflect their different holders. They bear interest at the rate of 7.5% per annum and are convertible at the option of the holder into shares of the Company’s common stock at a conversion price of $15.80 per share (the “7.5% Notes Conversion Price”). Upon written notice to the Company, the holders of the 7.5% Notes have the right to exchange all or a portion of the principal and accrued and unpaid interest under each such note for shares of the Company’s common stock at the 7.5% Notes Conversion Price. Additionally, subject to certain restrictions, the Company can force conversion of each 7.5% Note into shares of the its common stock if, following the second anniversary of the issuance of a 7.5% Note, such shares trade at a 40% premium to the 7.5% Notes Conversion Price for at least 20 trading days in any consecutive 30 trading day period. The entire principal balance of each 7.5% Note is due and payable seven years following its issuance and the Company may repay each 7.5% Note in shares of its common stock or cash. All of the shares issuable upon exercise of the 7.5% Notes have been registered for resale by their holders pursuant to a registration statement that has been filed with and declared effective by the Securities and Exchange Commission. The Amended Agreements restrict the use of the proceeds of the 7.5% Notes to financing the development, construction and operation of LNG stations and payment of certain related expenses. The Amended Agreements also provide for customary events of default which, if any of them occurs, would permit or require the principal of, and accrued interest on, the 7.5% Notes to become, or to be declared, due and payable. No events of default under the 7.5% Notes had occurred as of March 31, 2015.

On August 27, 2013, Green Energy Investment Holdings, LLC transferred $5,000 in principal amount of the 7.5% Notes to certain third parties.

As a result of the foregoing transactions, (i) Mr. Pickens holds 7.5% Notes in the aggregate principal amount of $65,000, which 7.5% Notes are convertible into approximately 4,113,924 shares of the Company’s common stock, and (ii) Green Energy Investment Holdings, LLC holds 7.5% Notes in the aggregate principal amount of $80,000, which 7.5% Notes are convertible into approximately 5,063,291 shares of the Company’s common stock.

At March 31, 2015, none of the proceeds from the 7.5% Notes were included in restricted cash as the Company had used the funds primarily to build LNG fueling stations.

SLG Notes

On August 24, 2011, the Company entered into convertible note purchase agreements (each, an “SLG Agreement” and collectively the “SLG Agreements”) with each of Springleaf Investments Pte. Ltd., a wholly-owned subsidiary of Temasek Holdings Pte. Ltd., Lionfish Investments Pte. Ltd., an investment vehicle managed by Seatown Holdings International Pte. Ltd., and Greenwich Asset Holding Ltd., a wholly-owned subsidiary of RRJ Capital Master Fund I, L.P. (each, a “Purchaser” and collectively, the “Purchasers”), whereby the Purchasers agreed to purchase from the Company $150,000 of 7.5% convertible notes due in August 2016 (each a “SLG Note” and collectively the “SLG Notes”). The transaction closed and the SLG Notes were issued on August 30, 2011. On March 1, 2012, Springleaf Investments Pte. LTD transferred $24,000 principal amount of the SLG Notes to Baytree Investments (Mauritius) Pte. Ltd.

The SLG Notes bear interest at the rate of 7.5% per annum and are convertible at each Purchaser’s option into shares of the Company’s common stock at a conversion price of $15.00 per share (the “SLG Conversion Price”). Upon written notice to the Company, the holders of the SLG Notes have the right to exchange all or any portion of the principal and accrued and unpaid interest under each such note for shares of the Company’s common stock at the SLG Conversion Price. Additionally, subject to certain restrictions, the Company can force conversion of each SLG Note into shares of its common stock if, following the second anniversary of the issuance of the SLG Notes, such shares trade at a 40% premium to the SLG Conversion Price for at least 20 trading days in any consecutive 30 trading day period. The entire principal balance of each SLG Note is due and payable five years following its issuance, and the Company may repay the principal balance of each SLG Note in shares of its common stock or cash. All of the shares issuable upon exercise of the SLG Notes have been registered for resale by their holders pursuant to a registration statement that has been filed with and declared effective by the Securities and Exchange Commission. The SLG Agreements provide for customary events of default which, if any of them occurs, would permit or require the principal of, and accrued interest on, the SLG Notes to become, or to be declared, due and payable. No events of default under the SLG Notes had occurred as of March 31, 2015.

In April 2012, $1,003 of principal and accrued interest under an SLG Note was converted by the holder thereof into 66,888 shares of the Company’s common stock. In January and February 2013, $4,030 of principal and accrued interest under an SLG Note was converted by the holder thereof into 268,664 shares of the Company’s common stock.

GE Loans

On November 7, 2012, the Company, through two wholly owned subsidiaries (the “Borrowers”), entered into a credit agreement (“Credit Agreement”) with General Electric Capital Corporation (“GE”). Pursuant to the Credit Agreement, GE agreed to loan to the Borrowers up to an aggregate of $200,000 to finance the development, construction and operation of two LNG plants (individually a “Project” and together the “Projects”).

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On December 29, 2014, the Borrowers and GE entered into an amendment to the Credit Agreement providing, among other things, that (i) the Credit Agreement will terminate if the initial loans under the Credit Agreement (collectively, “Loans” and, with respect to each Project “Tranche A Loans” and “Tranche B Loans”) for the Projects are not made prior to December 31, 2016 (rather than December 31, 2014, as the Credit Agreement originally provided), (ii) each Project must be completed by the earlier of (a) the date that is thirty months after the funding of the initial Loans with respect to such Project and (b) December 31, 2018 (rather than December 31, 2016, as the Credit Agreement originally provided) (with respect to each Project, the “Date Certain”), and (iii) prior to the funding of the Loans, the Borrowers will be required to enter into agreements with GE Oil & Gas, Inc. relating to the purchase of equipment for the Projects.

The Borrowers’ ability to obtain the Loans under the Credit Agreement is subject to the satisfaction of certain conditions, including each of the (i) acquisition of title to, or leasehold interests in, the sites upon which the Projects will be constructed, (ii) receipt of all governmental approvals necessary in connection with the design, development, ownership, construction, installation, operation and maintenance of the Projects, and (iii) commitment of all utility services necessary for the construction and operation of the Projects.

The Credit Agreement further provides that (i) the then existing Loans with respect to each Project must be converted into term loans with eight year amortization schedules (“Term Loans”) on or before the Date Certain with respect to such Project (the date of such conversion with respect to each Project, the “Conversion Date”), provided that if such Loans are not converted into Term Loans by the applicable Date Certain, such Loans must be repaid by the applicable Date Certain, (ii) each Term Loan will be due and payable on the eighth anniversary of the Conversion Date with respect to such Term Loan, and (iii) at any time prior to the applicable Conversion Date, the Loans may be prepaid in whole, and at any time after the applicable Conversion Date, the Loans may be prepaid in whole or in part. The Company expects the Loans to bear interest at an annual rate equal to the then- current LIBOR rate plus 7.00%, provided that for purposes of the Credit Agreement, the then-current LIBOR rate will always be at least 1.00%. The Credit Agreement includes various customary covenants, including debt service coverage ratios and a commitment fee on the unutilized loan amounts of 0.5% per annum, and also provides for customary events of default which, if such events occur, would permit or require the Loans to become or to be declared due and payable. As of March 31, 2015, the Company has not drawn any money under the Credit Agreement and was in compliance with the financial covenants. The commitment fee, which is charged to interest expense in the condensed consolidated statements of operations, was $250 for each of the three months ended March 31, 2014 and 2015.

The Loans are secured by (i) a first priority security interest in all of the Borrowers’ assets, including the Projects, and (ii) a pledge of the Borrowers’ outstanding ownership interests. In addition, the Company has executed a guaranty in favor of GE (“Guaranty”), pursuant to which the Company has guaranteed all of the Borrowers’ obligations under the Credit Agreement, including repayment of all Loans.

The Company and GE also entered an equity contribution agreement (the “EC Agreement”) pursuant to which the Company agreed to pay at least 25% of the budgeted cost of the Projects and all additional costs that exceed such expected budgeted costs, in each case, in the form of equity contributions to the Borrowers (“Equity Contributions”). The EC Agreement also requires the Company to provide, concurrent with GE’s extension of the initial Loans under the Credit Agreement, letter(s) of credit in an amount equal to the Company’s then-current unfunded Equity Contributions.

Concurrently with the execution of the Credit Agreement, the Company issued to GE a warrant to purchase up to five million shares of its common stock (see note 13).

5.25% Notes

In September 2013, the Company completed a private offering of 5.25% Convertible Senior Notes due 2018 (the “5.25% Notes”) and entered into an indenture governing the 5.25% Notes (the “Indenture”).

The net proceeds from the sale of the 5.25% Notes after the payment of certain debt issuance costs of $7,805 were $242,195. The Company has used, and intends to continue to use, the net proceeds from the sale of the 5.25% Notes to fund capital expenditures and for general corporate purposes.

The 5.25% Notes bear interest at a rate of 5.25% per annum, payable semi- annually in arrears on October 1 and April 1 of each year, beginning on April 1, 2014. The 5.25% Notes will mature on October 1, 2018, unless purchased, redeemed or converted prior to such date in accordance with their terms and the terms of the Indenture.

Holders may convert their 5.25% Notes, at their option, at any time prior to the close of business on the business day immediately preceding the maturity date of the 5.25% Notes. Upon conversion, the Company will deliver a number of shares of its common stock, per $1 principal amount of 5.25% Notes, equal to the conversion rate then in effect (together with a cash payment in lieu of any fractional shares). The initial conversion rate for the 5.25% Notes is 64.1026 shares of the Company’s common stock per $1 principal amount of Notes (which is equivalent to an initial conversion price of approximately $15.60 per share of the Company’s common stock). The conversion rate is subject to adjustment upon the occurrence of certain specified events as described in the Indenture.

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Upon the occurrence of certain corporate events prior to the maturity date of the 5.25% Notes, the Company will, in certain circumstances, in addition to delivering the number of shares of the Company’s common stock deliverable upon conversion of the 5.25% Notes based on the conversion rate then in effect (together with a cash payment in lieu of any fractional shares), pay holders that convert their 5.25% Notes a cash make-whole payment in an amount as described in the Indenture. The Company may, at its option, irrevocably elect to settle its obligation to pay any such make-whole payment in shares of its common stock instead of in cash. The amount of any make-whole payment, whether it is settled in cash or in shares of the Company’s common stock upon the Company’s election, will be determined based on the date on which the corporate event occurs or becomes effective and the stock price paid (or deemed to be paid) per share of the Company’s common stock in the corporate event, as described in the Indenture.

The Company may not redeem the 5.25% Notes prior to October 5, 2016. On or after October 5, 2016, the Company may, at its option, redeem for cash all or any portion of the 5.25% Notes if the closing sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which notice of redemption is provided, exceeds 160% of the conversion price on each applicable trading day. In the event of the Company’s redemption of the 5.25% Notes, the redemption price will equal 100% of the principal amount of the 5.25% Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for in the 5.25% Notes.

If the Company undergoes a fundamental change (as defined in the Indenture) prior to the maturity date of the 5.25% Notes, subject to certain conditions as described in the Indenture, holders may require the Company to purchase, for cash, all or any portion of their 5.25% Notes at a repurchase price equal to 100% of the principal amount of the 5.25% Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change purchase date.

The Indenture contains customary events of default with customary cure periods, including, without limitation, failure to make required payments or deliveries of shares of the Company’s common stock when due under the Indenture, failure to comply with certain covenants under the Indenture, failure to pay when due or acceleration of certain other indebtedness of the Company or certain of its subsidiaries, and certain events of bankruptcy and insolvency of the Company or certain of its subsidiaries. The occurrence of an event of default under the Indenture will allow either the trustee or the holders of at least 25% in principal amount of the then-outstanding 5.25% Notes to accelerate, or upon an event of default arising from certain events of bankruptcy or insolvency of the Company, will automatically cause the acceleration of, all amounts due under the 5.25% Notes. No events of default under the 5.25% Notes had occurred as of March 31, 2015.

The 5.25% Notes are senior unsecured obligations of the Company and rank senior in right of payment to the Company’s future indebtedness that is expressly subordinated in right of payment to the 5.25% Notes; equal in right of payment to the Company’s unsecured indebtedness that is not so subordinated; effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness (including trade payables) of the Company’s subsidiaries.

Canton Bonds

On March 19, 2014, Canton Renewables, LLC (“Canton”), a wholly owned subsidiary of the Company, completed the issuance of Solid Waste Facility Limited Obligation Revenue Bonds (Canton Renewables, LLC — Sauk Trail Hills Project) Series 2014 in the aggregate principal amount of $12,400 (the “Bonds”).

The Bonds were issued by the Michigan Strategic Fund (the “Issuer”) and the proceeds of such issuance were loaned by the Issuer to Canton pursuant to a loan agreement that became effective on March 19, 2014 (the “Loan Agreement”). The Bonds are expected to be repaid from revenue generated by Canton from the sale of RNG and are secured by the revenue and assets of Canton. The Bond repayments will be amortized through July 1, 2022, the average coupon interest rate on the Bonds is 6.6%, and all but $1,000 of the principal amount of the Bonds is non-recourse to Canton’s parent companies, including the Company.

Canton used the Bond proceeds primarily to (i) refinance the cost of constructing and equipping its RNG extraction and production project in Canton, Michigan and (ii) pay a portion of the costs associated with the issuance of the Bonds. The refinancing described in the prior sentence was accomplished through distributions to the Borrower’s direct and indirect parent companies who provided the financing for the RNG production facility, and such companies have used such distributions to finance construction of additional RNG extraction and processing projects and for working capital purposes.

The Loan Agreement contains customary events of default, with customary cure periods, including without limitation, failure to make required payments when due under the Loan Agreement, failure to comply with certain covenants under the Loan Agreement, certain events of bankruptcy and insolvency of Canton, and the existence of an event of default under the indenture governing the Bonds that was entered between the Issuer and The Bank of New York Mellon Trust Company, N.A., as trustee. The occurrence of an event of default under the Loan Agreement will allow the Issuer or the trustee to accelerate all amounts due under the Loan Agreement. No events of default under the Loan Agreement had occurred as of March 31, 2015.

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Other Debt

The Company has other debt due at various dates through 2020 bearing interest at rates up to 18.97% and with a weighted average interest rate of 6.80% and 6.81% as of December 31, 2014 and March 31, 2015, respectively.

Long-term debt and capital lease obligations at December 31, 2014 and March 31, 2015 consisted of the following:

Note 13—Net Loss Per Share

Basic net loss per share is based upon the weighted-average number of shares outstanding and issuable for little or no cash consideration during each period. Diluted net loss per share reflects the impact of the assumed exercise of dilutive stock options and warrants. On September 11, 2014, the Company determined it no longer met certain conditions required to include in its weighted average share calculations 4,000,000 of the 5,000,000 shares of common stock issuable upon exercise of a warrant issued to GE concurrently with the execution of the Credit Agreement (the “GE Warrant”).  As a result, since September 11, 2014, the Company has (i) excluded 4,000,000 shares of common stock issuable upon exercise of  the GE Warrant from the weighted average number of shares outstanding in the basic and diluted earnings per share calculations, and (ii) included the remaining 1,000,000 shares of common stock issuable upon exercise of the GE Warrant in the basic and diluted earnings per share calculations, as 500,000 shares issuable upon exercise of the GE Warrant were exercisable as of the execution of the Credit Agreement and an additional 500,000 shares issuable upon exercise of the GE Warrant became exercisable on December 31, 2014. The information required to compute basic and diluted earnings per share is as follows:

Certain securities were excluded from the diluted earnings per share calculations for the three months ended March 31, 2014 and 2015, respectively, as the inclusion of the securities would be anti-dilutive to the calculations. The amounts of these securities that were outstanding as of March 31, 2014 and 2015 are as follows:

Note 14—Stock-Based Compensation

The following table summarizes the compensation expense and related income tax benefit related to the stock-based compensation expense recognized during the periods:

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Stock Options

The following table summarizes the Company’s stock option activity during the three months ended March 31, 2015:

As of March 31, 2015, there was $6,445 of total unrecognized compensation cost related to non-vested shares underlying outstanding stock options. That cost is expected to be recognized over a weighted average period of 1.7 years. The total fair value of shares vested during the three months ended March 31, 2015 was $4,050.

The Company is obligated to issue shares of its common stock upon the exercise of outstanding stock options. The intrinsic value of all stock options exercised during the three months ended March 31, 2014 and 2015 was $1,387 and $486, respectively.

The fair value of each stock option granted during the three months ended March 31, 2015 was estimated as of the date of grant using the Black-Scholes option pricing model and the following assumptions:

The weighted-average grant date fair values of stock options granted during the three months ended March 31, 2015 and 2014 was $3.33 and $6.04, respectively. The volatility amounts used during these periods were estimated based on the Company’s historical volatility and the Company’s implied volatility of its traded options for such periods. The expected lives used during the periods were based on historical exercise periods and the Company’s anticipated exercise periods for its outstanding stock options. The risk free rates used during the periods were based on the U.S. Treasury yield curve for the expected life of the stock options at the time of grant. The Company recorded $1,782 and $1,520 of stock option expense during the three months ended March 31, 2014 and 2015, respectively. The Company has not recorded any tax benefit related to its stock option expense.

Market-Based Restricted Stock Units

The Company issued 2,034,500 market-based restricted stock units (“Market-Based RSUs”) to certain key employees during 2012 and 2014.  A holder of Market-Based RSUs will receive one share of the Company’s common stock for each Market-Based RSU held if (i) between two years and four years from the date of grant of the Market-Based RSU, the closing price of the Company’s common stock equals or exceeds, for twenty consecutive trading days, 135% of the closing price of the Company’s common stock on the Market-Based RSU grant date (the “Stock Price Condition”) and (ii) the holder is employed by the Company at the time the Stock Price Condition is satisfied. If the Stock Price Condition is not satisfied prior to four years from the date of grant, the Market-Based RSUs will be automatically forfeited. The Market-Based RSUs are subject to the terms and conditions of the Company’s Amended and Restated 2006 Equity Incentive Plan (the “2006 Plan”) and a Notice of Grant of Restricted Stock Unit and Restricted Stock Unit Agreement.

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The following table summarizes the Company’s Market-Based RSU activity during the three months ended March 31, 2015:

As of March 31, 2015, there was $1,685 of total unrecognized compensation cost related to non-vested shares underlying outstanding Market-Based RSUs. That cost is expected to be recognized over a weighted average period of 0.8 years.

The Company recorded $1,204 and $444 of expense during the three months ended March 31, 2014 and 2015, respectively, related to the Market-Based RSUs. The Company has not recorded any tax benefit related to its Market-Based RSU expense.

Service-Based Restricted Stock Units

The Company has issued service-based restricted stock units (“Service-Based RSUs”) to certain employees that vest annually over the three years following the date of issuance at a rate of 34%, 33% and 33%, respectively, if the holder is in service to the Company at each vesting date. The Service- Based RSUs are subject to the terms and conditions of the Company’s 2006 Plan and a Notice of Grant of Restricted Stock Unit and Restricted Stock Unit Agreement.

The following table summarizes the Company’s Service-Based RSU activity during the three months ended March 31, 2015:

As of March 31, 2015, there was $5,961 of total unrecognized compensation cost related to non-vested shares underlying outstanding Service-Based RSUs. That cost is expected to be recognized ratably over a period of 2.6 years.

The Company recorded $102 and $454 of expense during the three months ended March 31, 2014 and 2015, respectively, related to the Service-Based RSUs. The Company has not recorded any tax benefit related to its Service-Based RSU expense.

The fair value of each Service-Based RSU granted during the three months ended March 31, 2015 was estimated using the closing stock price of the Company’s common stock on the date of grant.

Employee Stock Purchase Plan

On May 7, 2013, the Company adopted an employee stock purchase plan (the “ESPP”), pursuant to which eligible employees may purchase shares of the Company’s common stock at 85% of the fair market value of the common stock on the last trading day of two consecutive, non-concurrent offering periods each year. The Company has reserved 2,500,000 shares of its common stock for issuance under the ESPP.

The Company recorded $27 and $15 of expense related to the ESPP during the three months ended March 31, 2014 and 2015, respectively. The Company has not recorded any tax benefits related to its ESPP expense. As of March 31, 2015, the Company had sold an aggregate of 72,815 shares pursuant to the ESPP.

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Non-Qualified Non-Public Subsidiary Unit Options

In September 2013, the Company’s wholly owned subsidiary, Clean Energy Renewable Fuels, LLC (“CERF”), adopted the Clean Energy Renewable Fuels, LLC 2013 Unit Option Plan (the “CERF Plan”). 150,000 Class B units representing membership interests in CERF were initially reserved for issuance under the CERF Plan.

The following table summarizes CERF’s unit option activity during the three months ended March 31, 2015:

As of March 31, 2015, there was $1,666 of total unrecognized compensation cost related to non-vested units underlying outstanding unit options issued pursuant to the CERF Plan. That cost is expected to be recognized over a weighted average period of 1.1 years.

CERF recorded $305 and $257 of unit option expense during the three months ended March 31, 2014 and 2015, respectively. CERF has not recorded any tax benefit related to its unit option expense.

Note 15—Environmental Matters, Litigation, Claims, Commitments and Contingencies

The Company is subject to federal, state, local, and foreign environmental laws and regulations. The Company does not anticipate any expenditures to comply with such laws and regulations which would have a material impact on the Company’s condensed consolidated financial position, results of operations, or liquidity. The Company believes that its operations comply, in all material respects, with applicable federal, state, local and foreign environmental laws and regulations.

The Company may become party to various legal actions that arise in the ordinary course of its business. During the course of its operations, the Company is also subject to audit by tax authorities for varying periods in various federal, state, local and foreign tax jurisdictions. Disputes may arise during the course of such audits as to facts and matters of law. It is impossible to determine the ultimate liabilities that the Company may incur resulting from any such lawsuits, claims and proceedings, audits, commitments, contingencies and related matters or the timing of these liabilities, if any. If these matters were to ultimately be resolved unfavorably, an outcome not currently anticipated, it is possible that such outcome could have a material adverse effect upon the Company’s consolidated financial position, results of operations, or liquidity. However, the Company believes that the ultimate resolution of such matters will not have a material adverse effect on the Company’s consolidated financial position, results of operations, or liquidity.

Note 16—Income Taxes

The Company’s income tax provision for the three months ended March 31, 2014 and March 31, 2015 was $962 and $854, respectively, which was comprised of taxes due on the Company’s U.S. and foreign operations. The effective tax rates for the three months ended March 31, 2014 and 2015 are different from the federal statutory tax rate primarily as a result of losses for which no tax benefit has been recognized.

The Company did not record a change in its liability for unrecognized tax benefits or penalties in the three months ended March 31, 2014 or March 31, 2015, and the net interest incurred was immaterial for such periods.

Note 17—Fair Value Measurements

The Company follows the authoritative guidance for fair value measurements with respect to assets and liabilities that are measured at fair value on a recurring basis and nonrecurring basis. Under the standard, fair value is defined as the exit price, or the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants, as of the measurement date. The standard also establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs market participants would use in valuing the asset or liability developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the factors market participants would use in valuing the asset or liability developed based upon the best information available in the circumstances. The hierarchy consists of the following three levels: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly; Level 3 inputs are unobservable inputs for the asset or liability. Categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.

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During the three months ended March 31, 2015, the Company’s financial instruments consisted of available-for-sale securities, debt instruments, and its Series I warrants. For available-for-sale securities, the fair values are determined by the most recent trading prices available for each security and for comparable securities, and thus represent Level 2 fair value measurements. The fair values of the Company’s debt instruments approximated their carrying values at December 31, 2014 and March 31, 2015. The Company uses the Black-Scholes model to value the Series I warrants. The Company believes the best method to approximate a market participant’s view of the volatility of its Series I warrants has been to use the implied volatilities of its short-term (i.e. 3 to 9 month) traded options and extrapolate the data over the remaining term of the Series I warrants, which was approximately 1.1 years as of March 31, 2015. This method has been utilized consistently in the periods presented. Given that the extrapolation beyond the term of the short-term exchange traded options is not based on observable market inputs for a significant portion of the remaining term of the warrants, the Series I warrants have been classified as a Level 3 fair value measurement.

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2014 and March 31, 2015, respectively:

(1) Included in short-term investments in the condensed consolidated balance sheets. See note 5 for further information.

(2) Included in other long-term liabilities in the condensed consolidated balance sheets.

The following table provides a reconciliation of the beginning and ending balances of items measured at fair value on a recurring basis in the table above that used significant unobservable inputs (Level 3) :

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Valuation Processes for Level 3 Fair Value Measurements and Sensitivity to Changes in Significant Unobservable Inputs

Fair value measurements of liabilities, which fall within Level 3 of the fair value hierarchy, are determined by the Company’s accounting department, who report to the Company’s Chief Financial Officer. The fair value measurements are compared to those of the prior reporting periods to ensure that changes are consistent with expectations of management based upon the sensitivity and nature of the inputs.

Series I Warrant Liability

The Company estimated the fair value of its Series I warrant liability using the Black-Scholes model based on the following inputs as of March 31, 2015:

Significant changes in any of those inputs in isolation can result in a significant change in the fair value measurement. Generally, a positive change in the market price of the Company’s common stock, an increase in the volatility of the Company’s common stock, or an increase in the remaining term of the warrants would result in a directionally similar change in the estimated fair value of the Company’s Series I warrants and thus an increase in the associated liability. An increase in the assumed discount rate or a decrease in the positive differential between the warrant’s exercise price and the market price of the Company’s common stock would result in a decrease in the estimated fair value measurement of the Series I warrants and thus a decrease in the associated liability. The Company has not, nor does it plan to, declare dividends on its common stock, and thus, there is no directionally similar change in the estimated fair value of the Series I warrants due to the dividend assumption.

Non-Financial Assets

No impairments of long-lived assets measured at fair value on a non-recurring basis have been incurred during the three months ended March 31, 2014 and 2015. The Company’s use of these non-financial assets does not differ from their highest and best use as determined from the perspective of a market participant.

Note 18—Recently Adopted Accounting Changes and Recently Issued Accounting Standards

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, amending revenue recognition guidance and requiring more detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The guidance is effective for annual and interim reporting periods beginning after December 15, 2016, with early adoption prohibited. The FASB has proposed a one-year deferral of the effective date. The Company is currently evaluating the impact this ASU will have on its consolidated financial statements.

In January 2015, the FASB issued ASU No. 2015-1, Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items. This guidance completely eliminates all references to, and guidance concerning the concept of, an extraordinary item from GAAP. The updated guidance is effective for annual reporting periods and interim periods within those annual periods beginning after December 15, 2015. Earlier adoption is permitted but the Company does not anticipate electing early adoption. The Company does not expect the adoption of this guidance to have a material impact on its consolidated financial statements.

In February 2015, the FASB issued ASU No. 2015-2, Amendments to the Consolidation Analysis, modifying the analysis regarding the evaluation of certain types of entities to be consolidated. Specifically, it (1) modifies the assessment of whether limited partnerships are variable interest entities (VIEs), (2) eliminates the presumption that a limited partnership should be consolidated by its general partner, (3) removes certain conditions for the evaluation of whether a fee paid to a decision maker constitutes a variable interest, and (4) modifies the evaluation concerning the impact of related parties in the determination of the primary beneficiary of a VIE. The updated guidance is effective for annual reporting periods and interim periods within those annual periods beginning after December 15, 2015. Earlier adoption is permitted but the Company does not anticipate electing early adoption. The Company does not expect the adoption of this guidance to have a material impact on its consolidated financial statements.

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In April 2015, the FASB issued ASU No. 2015-3, Interest - Imputation of Interest, requiring that debt issuance costs be presented in the balance sheet as a deduction from the carrying amount of the related liability, rather than as a deferred charge. The updated guidance is effective retroactively for financial statements covering fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Earlier adoption is permitted but the Company does not anticipate electing early adoption. As of March 31, 2015, the Company has $5,256 of debt issuance costs.

Note 19—Alternative Fuels Excise Tax Credit

From October 1, 2006 through December 31, 2014, the Company was eligible to receive a federal fuel tax credit (“VETC”) of $0.50 per gasoline gallon equivalent of CNG and $0.50 per liquid gallon of LNG that it sold as vehicle fuel. Based on the service relationship with its customers, either the Company or its customers claimed the credit. The Company records its VETC credits as revenue in its condensed consolidated statements of operations, as the credits are fully refundable and do not need to offset income tax liabilities to be received. VETC revenues recognized in December 2014 for the 2014 calendar year were $28,359. The Company did not recognize any VETC revenue during the three months ended March 31, 2015, as the program under which the Company received such credit expired December 31, 2014 and has not been renewed.

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

The following Management’s Discussion and Analysis of Financial Condition and Results of Operations (this “MD&A”) should be read together with the unaudited condensed consolidated financial statements and the related notes included in this report. For additional context with which to understand our financial condition and results of operations, refer to the MD&A for the fiscal year ended December 31, 2014 contained in our 2014 Annual Report on Form 10-K, which was filed with the Securities and Exchange Commission (“SEC”) on February 26, 2015, as well as the consolidated financial statements and notes contained therein (collectively, our “2014 10-K”). Unless the context indicates otherwise, all references to “Clean Energy,” the “Company,” “we,” “us,” or “our” in this MD&A and elsewhere in this report refer to Clean Energy Fuels Corp. together with its majority and wholly owned subsidiaries.

Cautionary Statement Regarding Forward Looking Statements

This MD&A and other sections of this report contain forward looking statements. We make forward-looking statements, as defined by the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, and in some cases, you can identify these statements by forward-looking words such as “if,” “shall,” “may,” “might,” “could,” “will,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “project,” “intend,” “goal,” “objective,” “predict,” “potential” or “continue,” or the negative of these terms and other comparable terminology. These forward-looking statements, which are based on various underlying assumptions and expectations and are subject to risks, uncertainties and other unknown factors, may include projections of our future financial performance based on our growth strategies and anticipated trends in our industry and our business. These statements are only predictions based on our current expectations and projections about future events that we believe to be reasonable. There are important factors that could cause our actual results, level of activity, performance or achievements to differ materially from the historical or future results, level of activity, performance or achievements expressed or implied by such forward-looking statements. These factors include, but are not limited to, those discussed under the caption “Risk Factors” in this report and in our 2014 10-K. In preparing this MD&A, we presume that readers have access to and have read the MD&A in our 2014 10-K pursuant to Instruction 2 to paragraph (b) of Item 303 of Regulation S-K. We undertake no duty to update any of these forward-looking statements after the date we file this report to conform such forward-looking statements to actual results or revised expectations, except as otherwise required by law.

Overview

We are the leading provider of natural gas as an alternative fuel for vehicle fleets in the United States and Canada, based on the number of stations operated and the amount of gasoline gallon equivalents (“GGEs”) of compressed natural gas (“CNG”) and liquefied natural gas (“LNG”) delivered. We design, build, operate and maintain fueling stations and supply our customers with CNG fuel for light, medium and heavy-duty vehicles and LNG fuel for medium and heavy-duty vehicles. We also manufacture, sell and service non-lubricated natural gas fueling compressors and other equipment used in CNG stations and LNG stations, provide operation and maintenance (“O&M”) services to customers, offer assessment, design and modification solutions to provide operators with code-compliant service and maintenance facilities for natural gas vehicle fleets, transport and sell CNG to large industrial and institutional energy users who do not have direct access to natural gas pipelines, process and sell renewable natural gas (“RNG”), which can be used as vehicle fuel or sold for renewable power generation, sell tradable credits we generate by selling natural gas and RNG as a vehicle fuel, including credits we generate under the California Low Carbon Fuel Standard (“LCFS Credits”) and Renewable Identification Numbers (“RIN Credits” or “RINs”) we generate under the federal Renewable Fuel Standard Phase 2, help our customers acquire and finance natural gas vehicles and obtain local, state and federal grants and incentives.

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We sell natural gas vehicle fuels in the forms of CNG, LNG and RNG. CNG is produced from natural gas that is supplied by local utilities and third-party marketers to CNG vehicle fueling stations, where it is compressed and dispensed into vehicles in gaseous form. We also provide CNG via trailers in its compressed form directly from the fueling station and by delivering and vaporizing LNG to turn liquefied natural gas into compressed natural gas. LNG is natural gas that is cooled at a liquefaction facility to approximately —260 degrees Fahrenheit until it condenses into a liquid, which takes up about 1/600th of its original volume as a gas. We deliver LNG to fueling stations via our fleet of 84 tanker trailers. At the stations, LNG is stored in above -ground tanks until dispensed into vehicles in liquid form. RNG is produced from waste streams such as landfills, animal waste digesters and waste water treatment plants. RNG production plants are connected to natural gas pipelines, which allow RNG to be transported to vehicle fueling stations, where it can be compressed and dispensed as CNG, and to LNG liquefaction facilities, where it is converted to LNG.

We serve fleet vehicle operators in a variety of markets, including heavy-duty trucks, airports, taxis, refuse, fleet services, ready mix and public transit. We believe these fleet markets will continue to present a high growth opportunity for natural gas vehicle fuels for the foreseeable future. At March 31, 2015, we served approximately 964 fleet customers operating approximately 41,669 natural gas vehicles, and we owned, operated or supplied 557 natural gas fueling stations in 42 states and in British Columbia and Ontario within Canada.

We believe we are positioned to capture a substantial share of the anticipated future growth in the use of natural gas as a vehicle fuel in the U.S. given our leading market share and the comprehensive solutions we offer.

Sources of Revenue

We generate revenues by selling CNG and LNG, providing O&M services to our vehicle fleet customers, designing and constructing fueling stations and selling those stations to our customers, processing and selling RNG, selling non-lubricated natural gas fueling compressors and related equipment for CNG and LNG fueling stations, providing maintenance services, offering assessment, design and modification solutions to provide operators with code-compliant service and maintenance facilities for natural gas vehicle fleets, transporting and selling CNG to large industrial and institutional energy users who do not have direct access to natural gas pipelines, providing financing for our customers’ natural gas vehicle purchases, selling tradable credits, including LCFS Credits and RIN Credits, and receiving federal fuel tax credits.

Key Operating Data

In evaluating our operating performance, our management focuses primarily on: (1) the amount of CNG and LNG gasoline gallon equivalents delivered (which we define as (i) the volume of gasoline gallon equivalents we sell to our customers, plus (ii) the volume of gasoline gallon equivalents dispensed at facilities where we provide O&M services, but do not sell the CNG or LNG, plus (iii) our proportionate share of the gasoline gallon equivalents sold as CNG by our joint venture with Mansfield Ventures LLC called Mansfield Clean Energy Partners LLC (“MCEP”), plus (iv) our proportionate share (as applicable) of the gasoline gallon equivalents of RNG produced and sold as pipeline quality natural gas by the RNG production facilities we own or operate), (2) our gross margin (which we define as revenue minus cost of sales), and (3) net loss attributable to us. The following table, which you should read in conjunction with our condensed consolidated financial statements and notes included in this report and our consolidated financial statements and notes contained in our 2014 10-K, presents our key operating data for the years ended December 31, 2012, 2013, and 2014 and for the three months ended March 31, 2014 and 2015: