Not many people consider a dog turd as an asset, or a rotting watermelon rind from last Sunday’s picnic. Too often items like these are simply regarded as trash that needs to be tossed – and the sooner the better before it starts to stink.
Wind and solar may be grabbing most of the headlines for renewable energy today, however, there are less celebrated and unused renewable energy resources that can add to our energy mix — especially waste-to-energy, writes Renewable Energy World.
Waste-to-energy applications include the traditional combustion of municipal solid waste methane gas to fire huge engines that generate electricity – a laudable technology already in place at some of the more advanced municipal landfills.
But a waste-to-energy resource that many are missing is the anaerobic digestion of mixed organic waste, such as food and yard waste, a technology that was introduce in Europe as far back as the 1930s. What are we missing here in the United States? This calls for putting some numbers to work.
The U.S. Environmental Protection Agency (EPA) estimates that 243 million tons of municipal solid waste (organic and non-organic) was generated in this country for 2008. Some 22 million tons of this organic waste was diverted for composting, an estimated 43 million tons of organic waste was sent to landfills. The total electric and thermal power associated with this organic waste is approximately 1 GW (electricity) and 1.4 GW(heat), respectively. The total electric output alone could serve close to 1 million homes.
If composting sound like a competitor to anaerobic digestion, the two are mutually beneficial, writes Renewable Energy World, because the remaining digestate from anaerobic digestion can be composted and sold. It cites a Washington composting facility, Cedar Grove Composting as an example.
European companies like Germany’s Viessmann (BIOFerm) and GICON Bioenergie GMBH and Austria’s Entec Biogas GMBH feature digester technology that already converts food waste, yard waste and other organic material into energy.
The lack of organic waste separation has been a big barrier for developing anaerobic digester projects in this country that can operate profitably. That may be changing, however. This March, Harvest Power, a producer of energy from organic waste, received a $51.7 million investment that included former Vice President Al Gore’s investment firm.
More news like this will lead our organic trash heap to a much higher use.