ethanol

Currently, 100 ethanol plants are operating in the United States, with 41 new plants or expansions under construction. The industry produced 4.7 billion gallons of ethanol in 2005, and the renewable fuels standard will provide a market for nearly 8 billion gallons by 2012. The industry is expected to invest an estimated $6 billion to build 4.3 billion gallons of new ethanol capacity by 2012 to meet this growing demand. As the market adjusts to meet this projected growth, the size and location of new dry mill ethanol plants are changing-from the current typical profile of 40 million to 50 million gallon per year (mmgy) plants located in the Midwest (where electricity prices are generally low) to new 100 mmgy plants sited not only in the Midwest, but also in the Northeast and California, where ethanol demand is concentrated and electricity prices are generally higher. These market shifts and available financial incentives are making CHP an even more economical choice for new facility construction and fuel production.

Dry mill ethanol plants are an excellent fit for CHP. They have large and relatively constant power and steam demands, and they operate 24 hours a day, 365 days a year. The size of the electricity and steam loads at ethanol plants closely matches the size of commonly available CHP technologies. Energy represents a large potion of dry mill ethanol production costs, second only to the cost of the corn used as the feedstock.

Demand for ethanol is growing. Ethanol is the primary replacement for MTBE, which is now banned in 22 states because of its environmental effects. In addition, ethanol's relative value has increased as gasoline prices climb. The inclusion of a new renewable fuel standard and fuel production tax credit in the Energy Policy Act of 2005 is expected to dramatically increase demand for ethanol and construction of new dry mill ethanol plants in the near future.

What can CHP do for Dry Mill Ethanol Facilties?

Combined heat and power can be an excellent solution for the energy needs of an ethanol plant. With CHP, a plant can:

Current Status

Despite CHP's excellent fit, adoption in this industry has been slow. Currently, only five U.S. dry mill ethanol facilities incorporate CHP into their operations:

How is CHP used in Ethanol Plants?

CHP technologies are flexible, providing many ways to apply CHP to the dry milling ethanol process.
  1. The most common CHP technology used in ethanol plants today consists of a gas turbine-electric generator unit, placed in tandem with a waste heat boiler. The turbine-driven generator provides electricity for the facility and the turbine exhaust is used in a waste heat boiler to produce process steam.
  2. Interest in biomass and coal CHP is growing. Biomass can be an option for ethanol plants located near sources of agricultural or forest waste or for plants looking to use the process byproducts as a fuel source.
  3. Ethanol plants with large thermal oxidizer loads can use a waste-heat boiler to produce steam from the oxidizer exhaust. High-pressure steam from the waste-heat boiler is used in a steam turbine-generator unit to produce electricity. Low-pressure steam from the back end of the turbine is used to meet process heat requirements.
  4. Other CHP options are also being explored for ethanol plants, including the integration of dryer exhaust VOC destruction into gas-fired turbine-generator systems.

Is Your Facility a Good Candidate for CHP?

  • Do you use more than 20,000 pounds per hour of steam?
  • Do you pay more than 6 cents per kWh for electricity?
  • Is reliable high-quality power important?
  • Is it important to reduce energy costs and increase the overall energy efficiency of your ethanol process?
  • Are biomass or alternative fuels readily available near your site?
  • Do you want to increase your plant's environmental performance?
If the answer to two or more of these questions is "yes," CHP can benefit your facility.