While we wait for renewable energy sources to scale up, we're going to need a stop-gap solution to put the brakes on global warming. A shiny new report (pdf) by the Department of Energy's Oak Ridge National Laboratory makes a pretty good case for combined heat and power (CHP) to fill that role.

CHP, also called cogeneration, greatly increases the efficiency of power plants by harvesting the heat that would normally be wasted and putting it to work. The average electric plant has a pitiful efficiency of 34%. And cogeneration? Up to 80%. Almost 3/4 of CHPs run on natural gas, but the technology works with other fuels such as biomass and digester gas.

In the study, the authors say that using CHP to generate 20% of U.S. electricity capacity by 2030 would reduce annual CO2 emissions by 848 million metric tons (MMT), the equivalent of taking half the US vehicle fleet off the road.

So why isn't this technology being used everywhere? These Oak Ridge boys see a number of barriers to widespread adoption, among them inefficient regulation, grid connection issues, and technical issues. To overcome these, the authors suggest revamped tax incentives, more renewable porfolio standards, and support for the right to sell electricity to distributors.

Today, cogeneration is a proven technology, popular in Europe and Japan as well as contributing about 9% of U.S. generating capacity. Carbon dioxide emissions are expected to grow by 961 MMT by 2020. CHP could reduce that amount by 60%.

While still not an ultra-clean solution, cogeneration may be one of the cheapest ways for America to reduce CO2 emissions in the near future. We'd be wise to put it to use.

Photo by Flickr user Siebuhr