Boeing: The New Solar Thermal King, In Patents

Boeing (s BA) is hardly a high-profile name in the world of solar thermal power development — firms like BrightSource Energy or Abengoa spring to mind a lot quicker. But Boeing, as it turns out, is the lord of solar thermal technology patents, according to a cleantech law firm.

A patent tracker by Heslin Rothenberg Farley & Mesiti shows that Boeing has snagged 14 solar thermal patents in the U.S. since 2002, more than any other company. The technologies covered include the use of molten salt to store energy and the heating of fluids to produce steam for running a generator, according to the Albany, N.Y., law firm’s latest Clean Energy Patent Growth Index (CEPGI).

Although Boeing hasn’t made headlines with its solar thermal technologies in recent years, it was once a key player when it came to building solar thermal power plants, including as part of a consortium that built Solar Two in California’s Mojave Desert. Solar Two was an experiment in developing the so-called “power tower” technology, which uses a field of mirrors to concentrate and direct sunlight to heat water or molten salt in a central tower. The steam produced is then used to run turbines for electricity generation.

Molten salt, a mixture of sodium and potassium nitrate, is good for energy storage and allows a power plant operator to use it even at night to run the generator.

Boeing and the other members of the Solar Two consortium, among them privately held Bechtel inaugurated the power plant in 1996. Solar Two lasted till 1999, as planned; the mothballed plant was recently detonated by Southern California Edison.

Boeing also had designs on co-developing a solar thermal power plant called Solar Tres in Spain, but ditched the idea, according to a 2007 presentation by Sener, a Spanish engineering firm.

Power tower technology is considered a newer — and some investors would say less proven — approach than the parabolic trough technology that relies on curved mirrors to heat fluid-containing pipes to generate the steam. BrightSource, based in Oakland, Calif., is a champion of the power tower technology. eSolar out of Pasadena, Calif., built a 5-megawatt power tower-based plant in Southern California last August.

The CEPGI also analyzed patents for solar-cell related patents (photovoltaics), and found Canon (s CAJ) to be the top dog. Canon has 2.5 times more patents than Sharp, the second on the list. Sharp is one of the top global producer of solar cells and panels and boasts 1 gigawatt of manufacturing capacity. Canon, on the other hand, is better known for making calculators and other gadgets embedded with solar cells.

But most of the 88 patents by Canon deal with what CEPGI calls “enabling technologies,” which aren’t part of the solar cells but help those cells to perform their task. Enabling technologies include power conversion, diodes and trackers.

By the way, Japanese companies dominate the list of top 15 PV patent holders, the CEPGI said. The top 3 are all Japanese firms and have collectively accumulated 17 percent of all PV patents. Boeing does rank No. 4 on the PV list because it owns solar-cell developer SpectroLab.

Solar patents aren’t as popular as wind and fuel cell patents, which reign among the cleantech categories tracked by CEPGI. But solar is gaining and could overtake wind this year, the law firm said.

Image courtesy of NREL.