LEASE EXTENSION AGREEMENT

Exhibit 10.48

LEASE EXTENSION AGREEMENT

This LEASE EXTENSION AGREEMENT (the “First Extension”) is made this 18th day of June, 2007 and is made a part of that certain Lease dated August 28, 2006, between WARNER COURTYARDS, LLC., an Arizona Limited Liability Company, METZGER WARNER COURTYARDS, LLC., a Delaware Limited Liability Company, PARK 3020, LLC., an Arizona Limited Liability Company, and PARK 3030, LLC., an Arizona Limited Liability Company, (“Landlord”) and CATALYTICA ENERGY SYSTEMS, INC., a Delaware Corporation (“Tenant”) regarding Suite 132 at the Warner Courtyards project, 301 W. Warner Road, Tempe, Arizona.

WHEREAS, said Landlord and Tenant wish to amend said Lease Agreement in the manner and to the extent hereinafter set forth.

NOW, THEREFORE, for and in consideration of the covenants and agreements herein contained and other good and valuable consideration, receipt and sufficiency of which is hereb