The Energy Blog

EPA Recognizes Innovative Landfill Gas Projects

Landfill gas is the natural by-product of the decomposition of solid waste in landfills and is comprised primarily of carbon dioxide and methane. By preventing emissions of methane (a powerful greenhouse gas) through the development of landfill gas energy projects, the Landfill Methane Outreach Program (LMOP) helps businesses, states, energy providers, and communities protect the environment and build a sustainable future.

Municipal solid waste landfills are the largest source of human-related methane emissions in the United States, accounting for about 25 percent of these emissions in 2004. At the same time, methane emissions from landfills represent a lost opportunity to capture and use a significant energy resource.

Landfill gas (LFG) is created as solid waste decomposes in a landfill. This gas consists of about 50 percent methane (CH₄), the primary component of natural gas, about 50 percent carbon dioxide (CO₂), and a small amount of non-methane organic compounds. Methane is a greenhouse gas over 20 times as potent as carbon dioxide at trapping heat in the atmosphere.

Instead of allowing LFG to escape into the air, it can be captured, converted, and used as an energy source. Using LFG helps to reduce odors and other hazards associated with LFG emissions, and it helps prevent methane from migrating into the atmosphere and contributing to local smog and global climate change.

Chevron, Fuel Cell Energy to Turn Wasetewater Sludge and Kitchen Grease into Renewable Power

Chevron Energy Solutions, a Chevron (NYSE: CVX) subsidiary, today announced that it has begun engineering and construction of a system at the City of Rialto’s (California) wastewater treatment facility that will transform wastewater sludge and kitchen grease from local restaurants into clean, renewable power.

The new system will provide a beneficial use for the thousands of gallons of fats, oils and grease (FOG) that are washed daily from restaurant grills and pans, which is collected by grease hauling companies. At the Rialto facility, a FOG-receiving station will provide an effective disposal alternative to landfills, where FOG is often disposed, creating methane - a greenhouse gas - as it decomposes, releasing it directly into the atmosphere. It also will provide a revenue stream to the city through “tipping fees” paid by grease haulers for each disposal.

Energy Usage Forecast

The June issue of Popular Science features an article on energy technologies that they say will cut our oil consumption in half and reduce our dependence on fossil fuels to produce electricity almost entirely by 2025.

They forecast that ultralight parts and plug-in hybrids could reduce fossil fuel consumption by 19% and that use of biofuels could reduce fossil fuel consumption by 30%.

Electricity needs could be reduced by the following technologies and conservation.

Home Electricity Conservation - 36%
Wind - 20%
Biopower - 17% (biomass gasification and methane generation)
Distributed Generation - 10%
Solar Power - 10% (PV and thermal solar power)
Geothermal Power - 5%
Ocean Power - 2% (wave power and tidal power)

While I don't think that I would have come up with the same numbers, the numbers give some idea of what mix of technologies could be used to reduce our dependence on fossil fuels.  My two concerns are that, while that degree of conservation proposed is possible, electricity costs would have to be extremely high before sufficient motivation for this degree of conservation would be possible.  After reducing consumption as much as forecast by conservation the percentage of electricity produced by wind, solar, and ocean power is higher than could easily be integrated into a grid, without massive energy storage or a much stronger grid, because of the intermittency of these generation methods.  Economical energy storage on a large scale is unlikely by 2025.  Geographical separation of these methods in an area as large as the U.S. reduces the effects of intermittency, but a much stronger grid is required to transport the energy from one area to another which would mean a very costly investment in the electrical infrastructure.  The area between the great plains and the east coast is not especially suitable for these methods and the grid would have to be reinforced significantly in this area. Superconducting power transmission would be especially useful, but development of economical systems is progressing rather slowly, although some usage could be expected by 2025.

I would hope that plug-in vehicles would be in wider use by this time, but that is very dependent on the acceptance of the technology by manufacturers. Their forecast for use of biofuels, although possible someday, is very unlikely by 2025.

The articles (without statistics) can be viewed at http://www.popsci.com/popsci/energy/