Exhibit 10(yy) BIG SPRING GUARANTEE This BIG SPRING GUARANTEE (this "Guarantee") is entered into as of August 4, 1998 by NEW WORLD POWER TEXAS RENEWABLE ENERGY LIMITED PARTNERSHIP, a Delaware limited partnership (the "Guarantor"), in favor of THE BANK...Spring Guarantee • May 28th, 1999 • York Research Corp • Cogeneration services & small power producers
