Republic Services, Inc. continues to greatly increase renewable energy output at its landfills. The company combined a first-of-its-kind solar technology with an existing biogas-to-energy system to turn its Tessman Road Landfill in San Antonio into a sustainable energy park. Republic’s solar power project won a gold medal from the Texas Council of Engineering Companies Engineering Excellence Awards in December 2009.
Republic’s green energy venture covers portions of closed areas of active landfills with flexible, laminate-type photovoltaic solar collection strips developed by United Solar. The flexible solar laminates, which capture the sun’s rays for conversion into electricity, are adhered directly to a Firestone-manufactured synthetic green-colored geomembrane used to cover and close a landfill as it reaches capacity. Unlike the more traditional rigid solar panels, which are bulky and frequently cost-prohibitive to install, Republic’s system uses flexible nonreflective collection strips less than 1/4 inch thick.
The flexible solar strips can be configured to maximize the hours of sunlight exposure throughout the year, depending upon a landfill’s design and site contours. For its demonstration project at the Tessman Road facility, Republic partnered with CPS Energy, greater San Antonio’s electric and natural gas provider, to deploy 5.6 acres of the 680-acre landfill with the solar energy cover, attaching over 1,000 solar strips to the landfill’s south facing side slope. The project became fully operational in March, 2009.
“As the nation’s largest municipally-owned gas and electric company, we’re proud that our customers’ energy bills are among the lowest in the country,” said Milton Lee, general manager and CEO. “We are able to do this by providing a diverse mix of fuels and renewable energy sources that combined offer reliable, cost-competitive electric service. Working together with Republic and the Texas Commission of Environmental Quality, we are at the forefront of yet another useful way to tap the energy resources of landfills for the benefit of our customers.”
The solar cover complements the landfill’s existing biogas-to-energy system, in operation since 2002. The system collects and processes biogas, which is naturally produced at the landfill through the decomposition of waste. The solar strips, which have flexible photovoltaic silicon cells that convert sunlight directly into electricity, will increase the amount of renewable energy provided by the landfill.
With over 300 days of sunlight in San Antonio per year, Republic estimates that the energy produced by the two fully-operational systems, will continuously create about nine megawatts of power - enough to power 5,500 area homes.
“As part of our commitment to creating cleaner, greener communities, we’re continually researching, developing and implementing innovative technologies to help us preserve and conserve our natural resources,” said Ted Neura, senior director, sustainable business planning and development for Republic Services.
“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, project manager for Republic. “Geomembrane covers are already in use across the country, but Republic is the first to integrate flexible solar cell technology to create an energy-producing cover system. We look forward to working with state regulators across the country to capitalize on the opportunities provided by landfills and, specifically, our efforts to further the country’s energy independence movement through new sources of solar power.”
Due to the success of the Tessman project, in 2011 Republic applied the same solar technology to the Hickory Ridge Landfill outside of Atlanta, Georgia.