AMENDMENT NO. 4 TO LEASE AGREEMENT

Exhibit 10.15

AMENDMENT NO. 4 TO LEASE AGREEMENT

     This Amendment No. 4 to Lease Agreement, dated as of December 31, 2008 (this “Amendment”), is entered into by and between CATALYST PAPER (SNOWFLAKE) INC., a Delaware corporation (“Landlord” or “Facility Operator”) an indirect wholly-owned subsidiary of Catalyst Paper Corporation, a Canadian corporation, and SNOWFLAKE WHITE MOUNTAIN POWER, LLC, an Arizona limited liability company (“Tenant” or “Facility Owner”).

RECITALS

     A. Landlord and Tenant have entered into that certain Lease Agreement, dated as of September 14, 2005 (as amended, amended and restated, supplemented or otherwise modified from time to time in accordance with the terms thereof and hereof, the “Lease”). Capitalized terms used herein but not defined herein have the meaning given in the Lease.

     B. Landlord, CoBank, ACB and Tenant have entered into that certain Consent and Agreement, dated as of September 1, 2006 (the “Consent”), pursuant to which the Lease was amended as described in the Consent.

     C. Landlord and Tenant have entered into that certain Amendment No. 2 to Lease Agreement, dated as of August 2, 2007 (“Amendment No. 2”), pursuant to which the Lease was amended as described in Amendment No. 2.

     D. Landlord and Tenant have entered into that certain Amendment No. 3 to Lease Agreement, dated as of August 23, 2007 (“Amendment No. 3”), pursuant to which the Lease was amended as described in Amendment No. 3.

     E. Landlord and Tenant wish to further amend the Lease as set forth herein.

     F. Renegy Holdings, Inc., the sole member of Tenant (“Renegy”), and AZ Biomass LLC, a Delaware limited liability company (“State Street”), contemplate entering into that certain Membership Interest Purchase Agreement to be dated as of January 1, 2009 (the “MIPA”) pursuant to which State Street will acquire from Renegy all the Class A membership interests in Tenant (the “Class A Interest”) for the consideration and on the terms as set forth in the MIPA.

     G. Pursuant to Section 22 of the Lease, Tenant has agreed not to assign, sublease, or otherwise transfer all or any portion of its interest under the Lease without the prior written consent of Landlord.

     H. The sale of the Class A Interest to State Street pursuant to the MIPA may be considered to be a “Transfer” of Tenant’s interest in the Lease, as such term is defined in paragraphs 3 and 4 of Section 22 thereof, and therefore Tenant has requested that Landlord consent to such Transfer of Tenant’s interest in the Lease.

     NOW THEREFORE, for good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereto agree as follows:

AGREEMENT

     1.  2009 Annual Budget . Facility Owner and Facility Operator agree that the Annual Budget (as defined in the Operations Provisions) for the Lease Year commencing January 1, 2009 and ending December 31, 2009 (the “2009 Lease Year”) shall be the budget attached to this Amendment as Exhibit A (the “2009 Annual Budget”).

     2.  Amendment of Lease . Landlord and Tenant agree that the Lease shall be amended as follows (with capitalized terms not otherwise defined herein having the meaning given in the Lease and section references referring to sections of the Lease):

          (a) Section 4.3 is hereby deleted in its entirety and replaced with the following:

     4.3 Paper Sludge Supply and Removal. Landlord currently operates the Paper Mill on property that is adjacent to the Real Property. For so long as the Paper Mill remains open and operating, Landlord shall allow Tenant to obtain without cost or charge as much of the paper sludge produced by the Paper Mill as Tenant can use at the Power Facility. Tenant will use commercially reasonable efforts to utilize the paper sludge as a fuel source for the Power Facility, but Tenant does not guarantee that the paper sludge will be a viable fuel source for the Power Facility. At no cost to Tenant, Landlord shall process the sludge to reduce the moisture content of such sludge to the lowest practical moisture content (in no event greater than approximately 50% moisture content) and shall be responsible for all waste water treatment in connection with the production and processing of such sludge. At no cost to Landlord, Tenant shall install equipment to transport the paper sludge from the wastewater treatment plant to the Power Facility, and shall add screw presses or other equipment necessary to allow Landlord to reduce the moisture content of the sludge. Tenant shall reimburse Landlord as an “Operational Cost” under the “Operations Provisions” the cost of transporting all such processed sludge to the Power Facility. In the event Tenant wishes to terminate its use of any or all of the paper sludge at the Power Facility, Tenant shall provide Landlord at least 30 days advance written notice of such termination. Any portion of paper sludge produced at the Paper Mill that is not taken by Tenant, including any sludge that Tenant discontinues using, may be sold or otherwise conveyed by Landlord to any third party; provided, however, that if Landlord desires to sell, transfer or convey any paper sludge to a third party (other than a transporter for purposes of disposal of the paper sludge in a landfill), Landlord shall first provide Tenant with 60 days’ notice of such desire and Tenant shall have the right to take possession and ownership of all the paper sludge produced by the Paper Mill. In the event Tenant fails to utilize at least 75% of the paper sludge (at current levels) produced at the Paper Mill within two (2) years after the Commencement Date, or thereafter fails to maintain such minimum usage, Tenant shall pay an annual rent of $400,000 in equal monthly installments. Any rent being paid under this Section 4.3 shall be suspended if the Paper Mill’s production of paper sludge falls below 25% of current levels, and shall resume when the production rises above 25% of current levels. Landlord

shall notify Tenant at least 90 days prior to permanently closing the Paper Mill or permanently ceasing production or processing of paper sludge. For purposes of this Section 4.3, current levels of paper sludge production shall refer to sludge production of 250 bone dry tons per day of Paper Mill operation. So long as the Operations Provisions remain in effect, any rent being paid under this Section 4.3 shall be suspended for any period during which Landlord, as Facility Operator, fails to use commercially reasonable efforts to utilize paper sludge taken by Tenant, consistent with Prudent Operating and Maintenance Practices.

          (c) Section 4.6 is hereby deleted in its entirety and replaced with the following:

     4.6 Utilities; Disposal of Facility Waste Other Than Fly Ash . Landlord shall provide utilities necessary to operate the Power Facility as described in this Section 4.6 so long as the Paper Mill is operating. The scope of such utilities shall be the same as those provided as of November 2008. Electricity shall be provided as described in Section 4.5 above. Natural gas will be provided as available at the metered cost. Water, boiler feedwater, compressed air, sewage and waste water treatment, and removal and disposal of Facility Waste will be provided to Tenant for a fixed rate of $375,000 per year. Landlord shall arrange for the transportation and disposal of all Hazardous Waste generated at the Power Facility in accordance with applicable law, and all costs associated therewith shall be considered an “Operational Cost” to be paid by Tenant. Landlord shall take possession of, transport and dispose of all Facility Waste in a location other than on the Real Property in accordance with applicable law, including, without limitation, all “Environmental Laws”. Tenant shall not have any financial responsibility with respect to the Facility Waste except as otherwise provided herein. Except as they relate to Tenant’s obligations under this Section 4.6 , any and all claims, demands, notices, damages, costs, fees, judgments, suits, causes of action, losses, liabilities and expenses, including attorneys’ fees and court costs, that result from or relate to the Facility Waste shall be considered Excluded Claims and shall be covered under Landlord’s indemnification obligations set forth in Section 12.3 . The rate charged Tenant for the foregoing services shall be adjusted on January 1, 2010, and on January 1 of each year thereafter, by the same percentage change as occurs during the prior calendar year in the cost to Landlord of providing utilities at the usage rates listed in Exhibit B attached hereto. The parties understand and agree that if the Paper Mill or any portion thereof is not operating for some temporary or indefinite period (but excluding a permanent closure) such that Landlord is not able to provide all of the utilities described herein during such period, Landlord and Tenant shall consult with one another in good faith to determine an acceptable means to supply the interrupted utilities. To the extent the interrupted utilities are provided by Landlord, the added costs incurred by Landlord shall be considered an “Operational Cost” to be paid by Tenant. The parties further understand and agree that the rate for the utilities described herein is based on the operations and efficiencies of the Power Facility as existing during November 2008. Should physical changes or changes in the method of operation of the Power Facility result in an increase in the demand for any of the utilities provided hereunder in

any Lease Year by more than 10% above the levels reflected in Exhibit B, the added cost to Landlord for providing utilities above the Exhibit B levels shall be considered an “Operational Cost” to be paid by Tenant. Should such changes result in a decrease in the demand for any of such utilities in any Lease Year by more than 10% below the levels reflected in Exhibit B, the decrease in the cost to Landlord for providing utilities below the Exhibit B levels shall be refunded to Tenant.

          (d) Section 4.7 is hereby deleted in its entirety and replaced with the following:

     4.7 Fly Ash Disposal .

     4.7.1 During the Lease Term, Landlord shall take possession of, transport and dispose of all Fly Ash in a location other than on the Real Property in accordance with applicable law, including, without limitation, all “Environmental Laws”. Tenant shall (i) reimburse Landlord, as an Operational Cost under the Operations Provisions, for all transportation costs incurred in removing and disposing of any Fly Ash, whether disposed of onsite or offsite of the Paper Mill, (ii) reimburse Landlord, as an Operational Cost under the Operations Provisions, for all disposal costs for Fly Ash disposed of offsite of the Paper Mill, and (iii) pay to Landlord an amount equal to $4.50 per ton of Fly Ash, having a moisture content of no more than 20%, disposed of onsite of the Paper Mill, provided that in no event shall Tenant be obligated to make any payments hereunder for any fees under this subsection (iii) that exceed $490 on any given day during the Lease Year. The foregoing rates charged to Tenant shall be adjusted effective January 1 of each year by the same percentage change as occurs in Landlord’s actual landfill costs during the prior calendar year. In the event the costs referenced in subsection “(i)” above are increased as the result of changes in the costs for services being provided to Landlord by a third party, Tenant shall have the option (exercisable no later than 30 days after receiving notice from Landlord of the adjustment) to assume the obligation to perform such services directly, subject to compliance with termination provisions in Landlord’s agreement with the third party, and subject to Tenant being able to perform such services at or exceeding the standards being met by such third party. To the maximum extent permitted by applicable law, (a) Tenant, and not Landlord, shall be considered the generator of the Fly Ash, and (b) the Power Facility, and not the Paper Mill, shall be considered the source of the Fly Ash.

     4.7.2 Notwithstanding anything to the contrary herein, in the event the Operations Provisions terminate prior to the termination of the Lease: (A) the cost for disposal of Fly Ash disposed of onsite of the Paper Mill shall increase to $7.50 per ton of Fly Ash having a moisture content of no more than 20% subject to a daily fee limitation of $818 (instead of $490); (B) Landlord shall continue to be obligated to take possession of, transport and dispose of the Fly Ash having a moisture content of no more than 20% as described above in Section 4.7.1 and any reimbursements required to be made by Tenant to Landlord described under subsections “i” and “ii” thereof shall continue to be required and shall be paid in

a manner consistent with Section 7.1.3 of the Operations Provisions (notwithstanding the termination thereof); (C) Tenant may elect upon 30 days notice to Landlord to assume all of Landlord’s obligations to take possession of, transport and dispose of the Fly Ash, in which case Tenant shall pay to Landlord the disposal costs listed in subsection “(A)” above, Landlord shall be relieved of its obligations under the foregoing subsection “(B)”; and the Fly Ash may continue to be disposed of on Landlord’s property (unless subsection “(D)” applies); (D) in the event (i) Tenant makes the election described in the foregoing subsection “(C)”, and (ii) the disposal of the Fly Ash on Landlord’s property is not commercially reasonable for Landlord, Tenant shall make arrangements to dispose of the Fly Ash offsite of Landlord’s property, and the disposal costs listed in subsection “A” would not apply. The foregoing rates charged to Tenant for disposal on Landlord’s property shall be adjusted effective January 1 of each year by the same percentage change as occurs in Landlord’s actual landfill costs during the prior calendar year. In the event the costs referenced in subsection “(i)” of Section 4.7.1 above are increased as the result of changes in the costs for services being provided to Landlord by a third party, Tenant shall have the option (exercisable no later than 30 days after receiving notice from Landlord of the adjustment) to assume the obligation to perform such services directly, subject to compliance with termination provisions in Landlord’s agreement with the third party, and subject to Tenant being able to perform such services at or exceeding the standards being met by such third party. Landlord may reject any Fly Ash having a moisture content of greater than 20%, in which case Tenant shall be responsible for disposing of the Fly Ash offsite of Landlord’s property in accordance with applicable law. If Tenant makes the election to assume Landlord’s obligations as described in this Section 4.7.2, any and all claims, demands, notices, damages, costs, fees, judgments, suits, causes of action, losses, liabilities and expenses, including attorneys’ fees and court costs, that result from or relate to the Fly Ash shall be covered under Tenant’s indemnification obligations set forth in Section 12.1;

     4.7.3 Tenant shall not have any financial responsibility with respect to the Fly Ash except as otherwise provided herein. Except as they relate to Tenant’s obligations under this Section 4.7 , any and all claims, demands, notices, damages, costs, fees, judgments, suits, causes of action, losses, liabilities and expenses, including attorneys’ fees and court costs, that result from or relate to the Fly Ash shall be considered Excluded Claims and shall be covered under Landlord’s indemnification obligations set forth in Section 12.3 .

     4.7.4 Tenant shall be responsible for any and all improvements, including, withou