You are here: home » technology » technology faqs

Technology FAQs

Are the Stirling solar dish systems suitable for residential and small business use?

Stirling energy systems are not currently available for small-scale applications at the present time. These systems are intended for utility-scale applications ranging from 1 MW to 1,000 MW or more.

Do Stirling's solar systems use photovoltaic technology?

No. This is a common misconception. Photovoltaic technology is generally not abundant enough or cost-effective enough to meet any large scale demands. The solar dish Stirling system is shaped much like large satellite dishes (approximately 38' in diameter) and covered with curved mirrors. These solar dishes are programmed to always face the sun and focus that energy on a collector in much the same way that a satellite dish focuses radio waves on a tuner. This collector is connected to a Stirling engine which uses the thermal power generated by the focused solar energy to heat hydrogen in a closed-loop system. The expanding hydrogen gas creates a pressure wave on the pistons of the Stirling engine which spins an electric motor creating electricity with no fuel cost or pollution. This technology is referred to as solar thermal or concentrating solar power.

How much power does a solar dish Stirling system produce?

One dish on an annual basis can produce 55,000-60,000 kWh of electricity. This is equivalent to the total energy required for about a dozen homes in the U.S.

When will the solar dish Stirling technology be ready for use in the mass marketplace?

The technology has completed research and development and is ready for large-scale utility development.

Is the solar dish Stirling system new technology?

This is a well established, reliable technology. The SES dish system was initially developed by Ford Motor Company in the late 1970's and later by McDonnell-Douglas in the mid 1980's. From 1998-2002, SES and Boeing were under contract with the Department of Energy's Sandia National Laboratories for a Dish-Engine Critical Components (DECC) program. Phase I of that program incorporated design enhancements to the Stirling dish system to increase performance and decrease and maintenance costs. Phase II, focused on system integration and successfully completion of the program. Independent reviews of the DECC program have concluded that there are no serious obstacles to commercialization of this technology and that this, and other concentrating power technologies, could contribute significantly to the U.S. supply of electricity from domestic sources.

What geographical areas are best suited for a solar dish farm?

The southwest region of the United States is ideally suited for this. Solar technology primarily addresses the peak power demands facing utility companies in the Southwest U.S. and other solar-rich areas.

In addition to reducing air pollution, how else does a solar dish Stirling system benefit the environment?

Stirling Dish Systems create no adverse environmental consequences.

  • With the exception of antifreeze used in the cooling system and the small amount of oil lubricant used in the Stirling engine, there are no toxic chemicals. The hydrogen gas used is sealed inside the engine; although small amounts will escape over time, hydrogen is a non-toxic substance that will diffuse rapidly into the atmosphere
  • The only fuel used is the sun
  • The only water used is that used to periodically wash the mirrors - only 4.4 gallons per MWh of energy produced (much less than traditional power generation usage)
  • The Stirling engine does not use internal combustion and is remarkably quiet, emitting less than 66 dB at full load
  • A Stirling solar plant will have no significant biological or cultural / paleontological / geological impacts. The system has a support post structure that is only about 18 inches in diameter, the result being comparable to the planting of a tree. The primary impact, after construction, is to provide shade
  • A solar dish Stirling plant requires only about one acre per 8 systems. Further, the solar plant will normally be located in underutilized land that is far from urban areas