Biomass Combined Heat and Power (CHP)-An Efficiency Multiplier

When considering a method of increasing the efficiency of electrical and thermal production, Combined Heat and Power (CHP) is an excellent choice. Typically the efficiency of a generator to produce electricity alone is in the 31 to 38 percent range. However, when the thermal is extracted from the system using the same fuel, the efficiency increases to approximately 80 to 82 percent. This is a great multiplier when considering one fuel in and two energy streams out is what is achieved in this manner. The technology has been available to all of us for many decades and now with the increase of petroleum costs again, the use of biomass as a fuel is a viable alternative. When we consider biomass fuel, we think of any biomass be it wood chips, pellets, straw, grass, or willow bush all of which can be easily be reproduced and is sustainable.

An obvious advantgage to a renewable energy system is that Renewable Energy Credits (REC's) can be obtained for each of the KWh that is produced at the energy plant under a long term contract with a buyer. It is important to analyze the system impact, Life Cycle Cost, and have an appropriate business plan in place for these projects to succeed.

Just as it is important to have a contract in place for the sale of electrical energy, thermal energy and Renewalbe Energy Credits, it is also important to have in hand a firm contract for the biomass fuel for the plant. Many times the fuel can be obtained from the operations of the existng plant thus reducing the overall cost of fuel. Along that line, it is important to keep the fuel throughput as low as possible per KWh so that the operating cost is as low as possible. We have seen some biomass gasification system produce eletctical power and thermal energy at a very low biomass fuel throughput when compared to other types of combustion units. When evaluating system selection with a particular fuel, we look at fuel, fuel cost, equipment efficiency with that fuel, reliability,distance to obtain the fuel,  parasitic load characteristics, and heating capacity of the fuel, among other factors.

We have done various biomass CHP projects including he North Country Healthcare Facility in Vermont. See the link below:

http://www.nrbp.org/publications/biomass-chp/appendixa.pdf


In general, each application is individual and needs to be accessed as it goes forward. For additional information, you might want to visit our web page at http://www.bonhagassociates.com/ for some articles that I have written about biomass cogeneration, combined heat and power systems, and energy efficiency improvement.

As a member of the US EPA CHP Partnership, and with many years of hands on practical experience designing mechanical, electrical, and energy systems for our clients, we are on the forefront of developments as they come to our attention for the benefit of our clients.