Stirling Energy Systems' 25 kW solar dish harnesses the power of the sun to make zero emissions energy. Stirling Energy Systems (SES) is a U.S. Phoenix, Arizona based company and recently (April 17, 2008) they announced that the company NTR plc of the United Kingdom had invested $100 million in them to take a controlling stake. On February 12, 2008 Stirling Energy Systems achieved a record 31.25% net efficiency in the conversion of solar energy to electricity, beating the earlier 29.4% efficiency of a Stirling Solar Dish set by Sandia National Laboratories in 1984.

Stirling Energy Systems' Solar Dish Engine has the commercial brand name of 'SunCatcher' and was developed in 1984 by McDonnell Douglas Corporation and Kockums of Malmo, Sweden. With the acquisition of McDonnell Douglas by Boeing, Boeing assumed the rights to the technology. In 1996 Stirling Energy Systems acquired the patent rights and a license to build the Kockums 4-95 Stirling Engine from Boeing. Boeing and SES continued to work jointly on the development of the Stirling Engine in conjunction with the U.S. Department Of Energy (DOE) as Phase I and II development trials between 1999 and 2001.

The Dish Stirling Engine is comprised of the solar concentrator and the power conversion unit (PCU). The PCU is a four cylinder hydrogen gas sealed arrangement and the cylinder assemblies are comprised of pistons and connecting rods along with coolers, regenerators, and heater heads. The entire PCU is held on the receiver arm of the dish. The heat transfer from solar rays to the heater head causes the hydrogen gas to expand in the piston and be exchanged between cylinder arrangements giving a maximum 1800 rpm speed and an output of 480 volts at 60Hz - all of this powered by the Sun with zero emissions to the environment.

SES's two most recent awarded contracts are: one from Southern California Edison (500 MW - signed 2005) for first phase completion Jan 2009, and one from San Diego Gas & Electric (300 MW - signed 2005). A 500 MW solar facility can power approximately a quarter million homes. Both of these contracts have expansion phase 2 clauses that could grow the total combined order by another 950MW or 1750 MW in total and a production of 70,000 SES Dish Engines. SES will build and operate the two solar energy power projects and provide electricity to the utilities.

The SES consortium of shareholders currently focus on build-operate high volume Solar Dish energy farms whose electricity is sold to major power companies. It is definitely a company to watch if they decide to release an Initial Public Offering (IPO) for capital infusion and also start to sell units individually in the commercial marketplace. The NTR plc investment should give Stirling Energy Systems the required capital to comercialise the SunCatcher Solar Dish technology and lower it's per unit manufacturing costs. The SES Solar Dish has applicability to all high solar intensity regions for the generation of zero emissions energy.