Solar-power technology meets waste management

Solar coverage for landfills provides great benefits

The American company Republic Services Inc. from Phoenix, Arizona has been developing energy production at its landfill through various means, which also include solar covers as a flexible collection of photovoltaic stripes affixed to the landfill. Republic has now decided to expand this technology by transferring the ownership of its solar landfill cover technology to Carlisle Energy Services Inc., which was contracted to provide the technology to put solar covers on other landfills. Carlisle, a subsidiary of Carlisle Construction Materials Inc., will build the systems starting with a portion of the Hickory Ridge landfill in Conley, Georgia, this year.

The solar cover consists of a synthetic geomembrane, typically used to seal a landfill that has a reached capacity. Adhered to the cover on the landfill’s south facing side slope are flexible strips with photovoltaic silicon collection cells that are about 0,5 cm thick.  This strips convert sunlight into electricity and complement the amount of renewable energy provided by the landfill. “The solar energy cover is easier to inspect, maintain and repair than a traditional clay cap, and is technically superior in terms of odor control and storm water management,” said Tony Walker, Republic Services project manager. A major advantage is also that it helps prevent oxygen intrusion to the landfill which can result in a higher quality biogas and the cover section can be pulled back easily to remediate for landfill settling.


The Republic Services landfill in San Antonio (the Tessman Road landfill) has received an award from the Texas Council of Engineering Companies in December 2009 for its use of this solar technology. Its solar cover of 2,26 ha of the 275 ha landfill produces along with a methane gas-to-energy system a combined 9 MW of electricity. Furthermore, there is also a 2 MW photovoltaic array at the For Carson landfill in Colorado, while New Jersey’s Erie landfill is to become the home of the largest solar energy farm in the state.


Solar powered trash compactors


Next to landfills photovoltaic technology is also being used to power trash compactors.  The Californian city Mission Viejo has become the latest in the string of cities to try out a new sustainable street-scale solar powered trash compactor. The so called BigBelly trash compactor uses the sun’s energy to compact waste at the point of disposal and promises to reduce collection trips by up to 80%. In addition solar technology and battery storage technology are rapidly approaching the point where solar equipment can operate without the need of direct sunlight every day. The American cities that have applied the solar trash compactors so far are Philadelphia (Pennsylvania), Boston (Massachusetts), Baltimore (Maryland), Chicago (Illinois), Los Angeles and Ventura (California), Queens (New York) and Banff in Canada.