The existence of intellectual property, in general, is an essential element of economic growth in a knowledge-based economy such as our own.

As a result, the number of patents issued annually by the U.S. Patent and Trademark often is cited as a measure of innovation and the effectiveness of research and development investments.

As with other technologies, issued patents in the clean energy sector are an indicator that efforts to develop new and non-obvious innovations have been successful, that the innovation had enough perceived value to justify the time and expense in procuring a patent, and that the economy is strong enough to support funds being dedicated the expense.

A review of recent trends in clean technology patents reveals that clean energy innovation has reached a new high:

Growth

The Clean Energy Patent Growth Index -- published quarterly by Heslin Rothenberg Farley & Mesiti's Cleantech Group -- provides an indication of the trends in innovative activity in the clean energy sector from 2002 to the present, on the state, federal and international levels, as well as insight into the leading patent owners and technologies in the clean energy sector.

Specifically, the index tracks issued U.S. patents for solar, wind, hybrid/ electric vehicles, fuel cells, hydroelectric, tidal/ wave, geothermal, biomass/biofuel and other clean, renewable energy.

Despite the current economic crisis, results through the fourth quarter of 2008 reveal, surprisingly, that last year's index was at its highest level to date, reaching a total of 928 granted patents. A breakdown by sector shows fuel cells dominating the other renewable energy technologies in raw numbers. Although there was slight decline in fuel cell patents issued in the fourth quarter compared to the third, the total fuel cell patents issued in 2008 (530) exceeded the 2007 number.

Patents in wind, hydroelectric, tidal and geothermal also were up in 2008 over 2007, with hydroelectric and tidal patents reaching at all time highs. Although the number of solar patents issued was substantially higher in the fourth quarter of 2008 compared to the first three quarters, the total was slightly lower than in 2007.

Similarly, hybrid and biomass/biofuel patents were higher in the fourth quarter of 2008 compared to the first three quarters, but the total number issued actually declined from 2007.

Perhaps most surprising in view of the recent auto bailout, CEPGI results for 2008 reveal that automobile companies comprise five of the top 10 leaders in clean energy patents, with three more in the top 25. Indeed, while Honda claimed the highest number of patents overall in 2008 (as it has since 2002), it did so just barely, beating General Motors by a mere two patents.

Fuel Cell manufacturers Plug Power, Ballard and United Technologies also appear in the top 10. The remaining top 10 spots belong to General Electric, based primarily on the strength of its wind patents (with an assist from solar technologies) and solar manufacturer, Canon.

Quality of clean energy patents

Analyzing the quality of renewable or clean energy patents granted is another way to monitor important technological breakthroughs in the Clean Tech arena.