In 2007, California produced 2.1% of its total electricity from biomass power plants. While this is just a small percentage of total power, it is unique in that the power generated is from what often would be dumped in landfills. In a very real sense, this power is created from our own garbage and leftovers. So, it’s a double win. New energy is created locally and what was an expense – trucking refuse to landfills and paying for the permits – now becomes an income stream, as the garbage gets turned into energy.
This is generally known as waste-to-energy, the burning of organic material to create power. There are four categories.
1) Biomass. Waste and by-products from forestry and agriculture are burned to generate power. A biomass plant in Shasta County processes 750,000 tons of forestry and mill waste a year, an enormous amount. Such fuel sources, as well as animal leftovers from meat packing plants, can also be used to create biofuel. For example, a sugar plantation in Maui that has its own refinery creates biofuel to run its equipment from bagasse, the leftovers of the refining process. Why throw something out when you can create energy and revenue from it instead?
2) Digester Gas. Food processing waste and especially livestock manure are put into airtight digesters where anaerobic processes create methane. Some large commercial livestock operations are already creating substantial amounts of their own energy from the methane, thus turning a huge liability – what to do with lagoons full of manure – into an asset. Plus, it prevents that same methane, a powerful greenhouse gas, from being released into the atmosphere and contributing to climate change.
3) Landfill Gas. This is similar to digester gas, except it is done at a landfill. Wells and pipes collect gases created naturally by rotting garbage. After further treatment, the gases are used to create electricity onsite or sold on the open market.
4) Municipal Solid Waste. Municipal dumps take the garbage and burn it for energy after separating out non-combustible items. While they get paid to take the fuel source, the process isn’t cost-competitive with other methods as yet. But still, it beats dumping everything into a landfill.
Other innovative methods of turning waste into energy include meat packing plants using beef tallow and leftover cooking oil to create biodiesel. Ethanol is being produced from corn cobs and other agricultural waste as well as from switchgrass, a weed-like plant that thrives in non-cropland areas and requires little water or fertilizer. In one year, the Spittelau Waste Incineration Plant in Austria created enough heat to warm 190,000 homes and 36.4 GWh of electricity as well.
Maybe one day all our cities and farms will routinely turn what once was regarded as trash into energy and fuel.