A survey has revealed a considerable boom in the issue of patents for and investments in renewable energy.

The figures show the validity and viability of the technology as both an earth-saver and money-maker – in the United States at least.

According to new research from MIT and the Santa Fe Institute (SFI), the number of patents issued in the last ten years has been astounding.

"We were quite surprised," says Jessika Trancik, an assistant professor of engineering systems at MIT and a co-author of report on spending and innovations in renewable industries, published in the journal PLoS ONE. 

To reach their results, a team created the database from energy-related patents issued in more than 100 countries between 1970 and 2009. They used keyword searches of the patents themselves, rather than the classifications assigned by patent offices. In all, the team examined more than 73,000 patents issued for energy-related technologies.

Ms Trancik said the database; “gives you a view into innovation activity - who's doing it, and where.”

Solar and wind energy patents saw the biggest increase, fossil-fuel efficiency efforts increased more moderately, and nuclear innovation was virtually nil. The numbers show the trend towards clean, green and infinitely available sources, though they may also indicate there is plenty of room for nuclear development in the modern age.

The team plotted the cumulative effect of investment in research, by governments and industry, and the effect of growth in the market for renewable-energy systems - which also benefitted from government subsidies, incentives and tax breaks.

Patents filed in China for renewable energy technologies have shown dramatic growth over the last few years too.

“China's really taking off,” Trancik says, adding that “understanding the nature of the technological development represented requires a close look at patent content.”

The report’s conclusion states that as new technologies often require a long time to develop, public investment is crucial at the early stage to allow the technology to take off before markets realise the potential.