Ethanol Plants

Why are Ethanol Plants are Good Candidates for CHP?

Needs of ethanol are consistent with the factors that are favorable for the economic attractiveness of CHP systems:

• Continuous power and steam demand
  
• Electric/steam loads match size of CHP technologies
  
• Electric power reliability and quality are valuable
  
• Long operating hours (typically 24 hours per day and seven days per week)
  
• Low differential between peak and base loads
  
• Energy is the second highest cost of production
  
• Electric and steam demands are large and coincident. For a 15 to 50 million gallon per year (MGY) facility:
  

• Typical power demand is 2 to 6 megawatts (MW)
  
• Typical steam use is 40,000 to 150,000 pounds per hour (lb/hr)
  

Benefits of CHP in Ethanol Plants

• Reliable steam and electricity generation on site
  
• Reduce energy and operating costs
  
• Reduce greenhouse gas emissions to help meet environmental goals
  
• Optimize alternative fuels as CHP can be designed to operate on any fuel
  
• Yield energy savings of 10-25%
  
• Plant keeps operating even if surrounding grid is down
  

How CHP is used in Ethanol Plants⁴

• Boiler/Steam Turbine CHP: Proven technology fired by solid fuel, including coal, biomass, or cofiring. Sized for thermal loads, may limit electrical production. If coal-fired, may pose permitting challenges.
  
• Gas Turbine CHP: Requires supplemental steam when the turbine is sized to meet the facility's electric load. By adding supplemental firing to the system, it can be sized to meet electric and thermal loads.
  
• Biomass CHP With Gasification: Least expensive fuel, but the technology is capital-intensive and still being commercialized. Considered "green" electricity if sold; tax credits could be available.
  
• Integrated Volatile Organic Compound (VOC) Destruction: Produces power with steam from thermal oxidizer or incorporates VOC destruction in turbine or boiler systems; can minimize compliance costs.
  
• Ethanol/Utility Partnerships: Public power companies and rural electric cooperatives are engaging in joint CHP ownership arrangements with ethanol facilities as thermal hosts in states including North Dakota, Missouri, and Kansas.
  

Case Studies of CHP Installations in Ethanol Plants

The Energy & Environmental Analysis, Inc. maintains a national database of CHP installations in various market sectors, including healthcare facilities. Search SIC Code 8051 for “Skilled Nursing Care Facilities” and SIC Code 8062 for “General Medical and Surgical Hospitals.” These databases for the Midwestern states are available at the following links:

The MAC has developed a searchable database of CHP installations. The database can be searched by building type (including hospitals), site installation location (State and City) , prime mover type and prime mover capacity.

Other Relevant Resources

Renewable Fuels Association (RFA) -The RFA is a national trade association for the U.S. ethanol industry. It promotes policies, regulations and research and development initiatives that will lead to the increased production and use of fuel ethanol.

EPA CHP Partnership -The EPA CHP Partnership is a voluntary program seeking to reduce the environmental impact of power generation by promoting the use of CHP. The Partnership works closely with energy users, including ethanol, the CHP industry, state and local governments, and other clean energy stakeholders to facilitate the development

• "From Niche to Nation: Ethanol Industry Outlook," Renewable Fuels Association, 2006, 24pp
  
  
• "An Assessment of the Potential of Energy Savings in Dry Mill Ethanol Plants from the Use of CHP," Energy and Environment Analysis Inc., July 2006, 8pp
  
  
• "Reduce Global Warming Intensity," Steffen Mueller & Richard Plevin, January 2008, 4pp
  
  
• "An Analysis of the Projected Global Warming Impact of Corn Ethanol Production," Steffen Mueller & Stefan Unnasch, Energy Resources Center, Aug. 30, 2007, 17pp
  
  
• "An Analysis of the Projected Energy Use of Future Dry Mill Corn Ethanol Plants," Steffen Mueller, Energy Resources Center, Oct. 10, 2007, 13pp
  
  
• "Utility-Ethanol Partnerships: Emerging Trend in District Energy/CHP," Ted Bronson (Power Equipment Associates), Kim Crossman (U.S. EPA CHP Partnership) and Bruce Hedman (EEA, Inc.), 2nd Quarter, 2007, 9 pp
  
  
• "Impact of Combined Heat and Power on Energy Use and Carbon Emissions in the Dry Mill Ethanol Process," Report prepared by EEA, Inc. for US EPA CHP Partnership, November, 2007, 13 pp
  
  
• "Integration of VOC Destruction and CHP in the Ethanol Industry," Report prepared by EEA, Inc. for US EPA CHP Partnership, June 2005, 13 pp.
  

Is CHP Right for Your Ethanol Plant?

Ask yourself the following questions:

• Do you use more than 20,000 pounds per hour of steam?
  
• Do you pay more than 6 cents per kilowatt-hour 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 is "yes" to two or more of these questions, CHP can benefit your facility.

For further information on whether CHP is a good option for your plant, the Midwest CHP Center's evaluation tools can be accessed here: Evaluation Tools - Midwest CHP Application Center.

References

• Reference No. 1
• Reference No. 2
• Reference No. 3A and 3B
• Reference No. 4