Press Release Back Number(2003)

Aiming to introduce a new distributed generation system in which exhaust heat can be utilized
- Evaluating the Stirling engine developed by STM Power in the United States -

August 6, 2003

Chubu Electric Power and Marubeni Corporation will jointly conduct a performance evaluation test of a distributed generation system based on a prototype of the Stirling engine commercialized by STM Power Inc. in the United States (http://www.stmpower.com/).

While conventional engines are driven by combustion of fuel in the cylinders, the Stirling engine drives pistons through the expansion and compression of the gas in the cylinders caused by external heating and cooling. This engine can use any heat source, including exhaust heat.

We have focused on the fact that commercializing small-scale distributed generation based on the Stirling engine, in which biomass* is used as fuel, will significantly reduce carbon dioxide generation, the cause of global warming.

* Biomass refers to biological resources such as that obtained from forestry thinnings, and is recognized as a renewable energy source by the Renewable Portfolio Standard (RPS) Law (Special Law on the Use of New Energy by Electric Utilities). Use of biomass is expected to help to reduce levels of carbon dioxide.

In theory, the Stirling engine provides excellent environmental performance, including high heat efficiency, low vibration, and low noise. But many technical barriers have prevented its commercialization. The Stirling engine of STM Power that we plan to evaluate has the following features:

  • Exhaust heat can be used for power generation.
    Exhaust heat from other engines and furnaces can be used. As a result, exhaust heat, which would otherwise be recovered only as hot water or steam, can be recovered as electricity.
  • The output of this engine ranges from several dozens to 300 kW.
    When used for distributed generation, it can generate electricity from small-scale heat sources and exhaust heat. (The current type can generate several dozens of kW of electricity. The development of an engine with an output of 300 kW is planned.)
  • Biomass can be used as fuel.
    This engine paves the way for the development of small-scale distributed generation using biomass products such as wood from forestry thinning and agricultural waste as fuel. This external combustion engine does not require the gasification of fuel, and is capable of directly using the exhaust heat obtained through the burning of wood biomass.

    • When a new type of distributed generation based on the Stirling engine is used in Japan, it must satisfy the technological standards established in the Electricity Utility Law. We asked the Ministry of Economy, Trade and Industry to evaluate its conformity to the technological standards. A committee for evaluating the conformity of the engine to technological standards will be established on August 8.

    After the committee completes its evaluation, we will begin using the prototype to evaluate its performance and durability and the system's potential for use of exhaust heat.