Spark-Assisted HCCI Residential Generator

Spark-Assisted HCCI Residential Generator

Madison, Wisconsin
Project Term:
12/17/2015 - 10/16/2021

Critical Need:

In 2013, centralized U.S. power plants had an average electricity generation efficiency of only 33%, wasting 67% of primary energy as heat and emitting 2 billion tons of CO2, about 38% of U.S. total emissions. Further, 6% of electricity is generally lost during transmission and distribution from the power plant to the customer. An alternative to centrally produced power is distributed generation, in which electricity is generated at the point of use. Residential combined heat and power (CHP) systems can burn natural gas to produce electricity for a home while also using the waste heat for space and water heating. The potential energy efficiency for CHP systems is more than 80% and significant adoption of such systems would enable dramatic reductions in primary energy use and concurrent CO2 emissions. However, usage of small CHP systems is not widespread because systems currently on the market are limited by high price, low efficiency, and short lifetime. The GENSETS program seeks to develop 1 kW (electric) CHP generators that have high fuel-to-electricity generation efficiency, long life, low cost, and low emissions.

Project Innovation + Advantages:

Wisconsin Engine Research Consultants (WERC) and its partners Adiabatics, Briggs and Stratton, and the University of Wisconsin-Madison will develop a generator using an internal combustion engine (ICE) that incorporates an advanced spark-assisted homogeneous charge compression ignition (SA-HCCI) system. Traditional internal combustion engines use the force generated by the combustion of a fuel (e.g. natural gas) to move a piston, transferring chemical energy to mechanical energy. This can then be used in conjunction with a generator to create electricity. SA-HCCI systems achieve combustion by compressing their fuel/air mix to the point of ignition, with a spark helping to initiate the process. These systems run very fuel lean and achieve high efficiency and waste less heat compared to conventional ICEs. In addition, the WERC team will further increase efficiency by incorporating thermal barrier coatings, an advanced boost system, and an optimized low-friction combustion chamber.

Potential Impact:

If successful, WERC’s project will facilitate development and commercialization of economical, efficient, and durable CHP systems for residential use. These advancements support progress toward ARPA-E’s overall goals as follows:


Innovations developed in this project could help households and businesses become more energy self-reliant and less susceptible to energy-related outages through distributed, local generation of power and heat.


Widespread adoption of high-efficiency residential CHP systems could decrease overall primary energy consumption and therefore reduce CO2 emissions associated with electricity generation by up to 10%.


Cost-effective natural gas-fueled residential CHP systems could offer consumers lower electricity and heating bills.


ARPA-E Program Director:
Dr. David Tew
Project Contact:
Prof. Rolf Reitz
Press and General Inquiries Email:
Project Contact Email:


Briggs and Stratton
University of Wisconsin - Madison, Engine Research Center (ERC)
Adiabatics, Inc.

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