The fourth quarter of 2008 saw a record high number of patents filed for clean energy technology. An intellectual property law firm that conducted the survey on the clean energy tech patents showed that in total, there were 928 clean energy patents approved.

Of the total clean energy technology patents granted since 2002, Honda had the most followed by General Motors. Other easily recognizable corporations in the top 10 included automakers Toyota, Nissan, Ford as well as Plug Power, the fuel cell developer.

Fuel cell patents accounted for a vast majority of clean energy patents approved with more than 500. Honda alone registered 49 fuel cell patents with General Motors right behind with 48, Toyota with 23 and Nissan with 19.

There was also growth in patents approved in the categories of hydroelectric, tidal power as well as geothermal power. But wind power scored the most with 155, 27 of which were granted to General Electric.

Interestingly, solar power patents as well as hybrid vehicle and electric vehicle patents all declined. The most patents secured by a company last year was Sunpower Corp. with six.

The United States continued to dominate the number of green patents granted internationally with more than 50 percent of all companies and organizations being U.S. based. Japan followed with 29 percent and Germany was next with eight.

The United States has actually been filing fewer clean energy technology patents every year since 2004 while Japan had been filing more each year.