| 20090136298 | Collection of landfill gas at variable rates to match temporal needs for energy generation - The invention involves a method of collecting biogas from a landfill with a variable rate of collection varied to match periods of greatest need for energy and greatest economic value of energy during a day. The variable collection rate is made possible by a landfill design that includes a gas permeable layer and a gas containment layer with gas collection from an extraction locus beneath the gas permeable layer. In some embodiments the landfill also includes a porous gas storage layer above the gas-permeable layer. | 05-28-2009 |