Online DOE training seminar offers details about cogeneration

By Holly Jessen | April 03, 2013

Ethanol producers interested in learning more about combined-heat-and-power (CHP) may want to check out an archived U.S. DOE training seminar. The information complements “Feeling the Heat,” a story about CHP at ethanol facilities, which was recently published in the April issue of Ethanol Producer Magazine

The seminar, originally held online Feb. 7, is part of the Federal Energy Management Program’s First Thursday Seminars. CHP is based on proven technology and practices and provides multiple benefits, according to the seminar. On the other hand, there are challenges, including financial uncertainty, cost and uncertainty in the areas of utilities and regulations.

The DOE has calculated that more than two-thirds of the fuel used to generate power in the U.S. is lost as heat. CHP captures much of that heat, increasing energy efficiency. A power plant is only 32 percent efficient while a boiler or furnace system is 80 percent efficient, meaning a facility utilizing power from a power plant and a boiler or furnace has a combined energy efficiency of 50 percent. In comparison, CHP is 75 percent efficient, resulting in energy and greenhouse gas emission savings.

The two types of CHP are conventional, or topping cycled CHP, and waste heat-to-power CHP, or bottom topping CHP, according to the seminar. Conventional CHP utilizes a heat recovery steam boiler with a fuel, such as natural gas, as the prime mover and generator. Waste heat-to-power CHP utilizes a steam turbine waste heat from an industrial process and results in no incremental emissions if no additional fossil fuel is combusted.

As of 2011, a total of 82 gigawatts of CHP was installed at nearly 4,000 industrial and commercial facilities. Every year, the technology allows more than 1.8 quadrillion Btus of fuel consumption to be avoided and a reduction in C02 emissions equivalent to eliminating forty 1,000 megawatt coal power plants, the DOE said. Of existing CHP capacity, half are powered by combined cycle, with the next most common system including a boiler/steam turbine. Natural gas is the No. 1 fuel source, with 71 percent of existing CHP systems utilizing natural gas. The remaining fuels include coal, waste, biomass, wood and oil.

Is your plant a good candidate for CHP?

The first step in assessing a facility for CHP is a simple screening and preliminary analysis. Three or more “yes” answers indicates a good fit.

Do you pay more than 6 cents per kwh on average for electricity (including generation, transmission, and distribution)?

Are you concerned about the impact of current or future energy costs on your business?

Are you concerned about power reliability? What if the power goes out for 1 hour? For 5 minutes?

Does your facility operate for more than 3,000 hours/year?

Do you have thermal loads throughout the year?

Does your facility have an existing central plant?

Do you expect to replace, upgrade or retrofit central plant equipment within the next 3 to 5 years?

Do you anticipate a facility expansion or new construction project within the next 3 to 5 years?

Have you already implemented energy efficiency measures and still have high energy costs?

Are you interested in reducing your facility's impact on the environment?

The next steps in the CHP project process are a feasibility analysis, investment-grade analysis followed by procurement, operations and maintenance of a CHP system.

SOURCE: U.S. DOE

What are the benefits of CHP?

CHP plays an important role in meeting U.S. energy needs as well as in reducing the environmental impact of power generation. Benefits include:

Efficiency: CHP requires less fuel to produce a given energy output, and avoids transmission and distribution losses that occur when electricity travels over power lines.

Reliability: CHP can be designed to provide high-quality electricity and thermal energy to a site regardless of what might occur on the power grid, decreasing the impact of outages and improving power quality for sensitive equipment.

Environmental: Because less fuel is burned to produce each unit of energy output, CHP reduces air pollution and greenhouse gas emissions.

Economic: CHP can save facilities considerable money on their energy bills due to its high efficiency and can provide a hedge against unstable energy costs.

SOURCE: U.S. DOE