221 New Developments in Gas Engine Gensets

Today's gas engine generator sets are used for peak shaving, intermediate load, and base load installations. The use of reciprocating engines for power generation is constrained by the prices of gas and electric utility power. Lower specific capital cost and greater efficiency are the obvious keys to improving gas engines' competitive position. Figure 2.8 shows how specific capital cost and efficiency affect a distributed generation power plant, used primarily for peak shaving at 3200 operating hours per year. The internal rate

Internal Rate of Return (%)

n35% Efficiency S40% Efficiency

$400/kW $500/kW $600/kW $700/kW $800/kW Capital Cost ($/kW)

$400/kW $500/kW $600/kW $700/kW $800/kW Capital Cost ($/kW)


Internal rate of return for various initial engine costs.

of return, based on an after-tax cash flow analysis, climbs rapidly when installed costs are reduced and efficiency is enhanced.

Recognizing environmental and efficiency needs, engine manufacturers, industry associations, and government agencies have embarked on programs to advance gas engine technology. The next several years should see significant investments in basic research and development dealing with engine air intake, fuel and combustion systems, controls, and safety systems, as well as power generation and interconnection devices.

In 1996, the Gas Research Institute (GRI) launched a series of gas engine development projects to target improvements specifically for the distributed generation market. These efforts included two joint programs with engine manufacturers. The Advanced Reciprocating Gas Engine Technology (TARGET) program, launched in 1997, aims to develop, demonstrate, and commercialize a higher-speed (1800 versus 1200 rpm), high-output, lean-burn, spark-ignited gas engine. From the base unit, a widely used 16-cylinder engine rated at 820 kW, the project goal is to deliver:

• 30% lower engine and generator first cost ($/kW)

• 38% engine shaft efficiency (a 6% increase from 36%)

The program began in late 1997, and the TARGET engine completed test cell runs in 1998 and 1999.

The second GRI project involved development of a high-output, dual-fuel engine using micropilot prechamber technology. Compression ignition of diesel pilot fuel eliminates spark plugs and ignition system components. The project's primary goal is to boost power output in an existing engine series by 40%, resulting in an output range from 1.1 to 3.3 MW. Shaft efficiency is projected at 38 to 41% with NOx emissions less than 0.75 g/bhp-hr.

Longer term, the U.S. Department of Energy, with technical assistance from GRI and Southwest Research Institute, supports the Advanced Reciprocating Engine Systems (ARES) consortium, aimed at further substantial advances in gas engine performance over the next five to seven years, starting in 2001. The ARES project goal is to produce a commercially viable gas engine delivering 50% engine shaft efficiency and NOx emissions of less than 0.1 g/bhp-hr.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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