Sometimes the numbers fail to tell the whole story.

According to a recent Ernst & Young LLP analysis based on data from Dow Jones VentureSource, US venture investment in clean technology companies has decreased by 44% over the past year to $1.1 billion. But overall investments may not accurately depict the future of the maturing cleantech market, the study implies.

“It would not fair to just look at the headline on the decline; mathematically it shows a decline, but when you look underneath and the nature of investing, you do have things period to period with different dynamics,” said Ernst & Young LLP’s Americas Cleantech Director Jay Spencer.

Investments in clean technology companies slipped from the same period in 2010, but interest in the solar industry remained robust, driving in 21% of total investments for the quarter.

The report indicates that largest dollar invested component for the first half of 2011 came from the Energy/Electricity segment with a total of $686.9 million, a sum almost equal to the $700.6 million raised the previous year. Within the segment, solar companies were credited for the bulk of the investments as well as securing the largest single deal of the quarter at $168 million.

Efficiency Transactions Highlighted

Complementing the solar industry’s lead in dollars raised, the Energy Efficiency segment ranked third in total amount while securing 20 deals, the largest total for the quarter. Hara Software, a Northern California provider of environmental impact measurement, was responsible for the largest deal in that sector, raising $25 million.

The solar industry’s success links to government funding is still open for debate, the report implies, as it still provides a significant amount of money but has begun to take a back seat to private investing. The DOE offered conditional loan guarantees of more than $32 billion to support 32 clean-energy projects, $10 billion of which will go to solar projects.

Analysts do not universally see government involvement as responsible for the maturing solar market. Spencer told Breaking Energy that although the government plays a role in the market, venture investment are not focused on tax incentives and federal guarantees.

“Top venture capitalists are not investing in opportunities that are going to be reliant on subsidies to make the market,” Spencer said. “Venture investors are looking at things that can take advantage of a market opportunity by themselves, on their own, without any extra support.”

Photo Caption: Jesse Grossman of Soltage and Tom Burton of Mintz Levin speak during the “Financing Solar – From Project Finance to PPAs” panel on Nov 13, 2007. This picture was originally posted by Greentech Media on flickr. Breaking Energy covered Greentech’s conference in 2011. Read the full story: Future Shock As California Utilities Admit Smart Grid Risks.