Press Release Back Number(2005)

Start of Operation of 55-kW Stirling Engine

September 20, 2005
Chubu Electric Power Co., Inc.

In partnership with Marubeni Corporation (President and CEO: Nobuo Katsumata; Address: 4-2, Otemachi 1-chome, Chiyoda-ku, Tokyo), we began research in preparation for the introduction of Stirling engines to Japan in FY 2003. Additionally, we asked the Ministry of Economy, Trade and Industry to conduct technological standard conformity assessments of these engines. Based on the initial results of these assessments, we recently received permission for the limited use of a 55-kW Stirling engine in Japan, and began operations to test performance of this engine, made by the US company STM Power, Inc. (http://www.stmpower.com/).


While a conventional engine uses the expansive force generated from combustion in its cylinders, a Stirling engine moves its pistons by external heating and cooling (causing expansion and contraction) of the cylinder gas. This mechanism enables the use of various types of heat sources or fuels, including solid fuels such as biomass*. Theoretically, the Stirling engine can provide outstanding environmental performance: high heat efficiency, low vibration, and low noise. However, due to the many challenges in development, there have been few cases of successful practical use of a Stirling engine. The STM Power Stirling engine we will evaluate is the first marketed for commercial use anywhere in the world.


* Biological resources such as lumber from thinning. Biomass is recognized as a renewable energy source under the Renewables Portfolio Standard (RPS) Law, and is included among promising measures to reduce carbon dioxide emissions.


On this occasion, we will operate the engine using municipal gas to study basic performance.


We are planning to begin testing of a compact wood-biomass power generation system employing a Stirling engine by the end of FY 2005. To explore the engine's potential for use in biomass power generation, this testing will be incorporated into joint R&D of a compact biomass direct-injection power generation system, in cooperation with the New Energy and Industrial Technology Development Organization (NEDO) and C-Tech Corporation (President: Masao Shimizu; Address: 4-45 Sugumo-cho, Mizuho-ku, Nagoya)


This small-scale distributed power supply using wood biomass is expected to help significantly curb emissions of carbon dioxide, a major cause of global warming.


Specifically, we are focusing on the following features of STM Power's Stirling engine:

Biomass can be used as fuel

This engine paves the way for development of small-scale distributed power supplies that use biomass such as lumber from thinning and agricultural waste. An external-combustion engine such as this eliminates the need for gasification of fuel, and directly uses exhaust heat from the combustion of wood biomass or the like, reducing equipment costs.

Compact body and outstanding environmental performance

Through the use of high-pressure hydrogen as the working gas and the compact structure of the body, this engine offers high heat efficiency, in addition to outstanding environmental performance-from low noise to low vibration and low emissions of nitrogen oxide.

Engine output on the order of 50 kW

The engine's ability to generate power using a small-scale heat source or exhaust heat can be applied to a number of needed applications. The use of several engines in parallel can generate up to several hundred kilowatts of energy.