Venture capital investment in cleantech in the second quarter totaled $2.02 billion across 140 companies in North America, Europe, China and India. A little down from the $2.04 billion invested in the first quarter, the total still reflects a 65 percent increase from the halfway mark last year, according to a report released today by the Cleantech Group and Deloitte.

The first quarter of 2010 saw a record number of cleantech deals: 192. So compared to that, the Q2 figures are a little lackluster, but still 43 percent higher than those from Q2 last year.

The report also noted a few trends shaping venture capital involvement in the sector. Perhaps most significantly, more funding is coming from major corporations looking to grow their presence in the green technology movement. General Electric, Chevron, Intel, IBM and Cisco Systems have all played a major role in helping solar, smart grid, wind, biofuel and even water startups achieve scale. Corporate investments jumped to $5.1 billion, a 325 percent increase from last year.

On top of that, power purchase agreements between utilities and solar, wind and other alternative energy companies became a much more common practice — predictable with so much new renewable energy generation connecting to the grid. The report states that the number of power purchase agreements rose 148 percent from 621 megawatts under contract to 1,539 megawatts between this year and last. With so many utilities needing to hit renewable energy mandates by nearing deadlines, this figure will no doubt continue to rise.

Here’s how the data broke down across the sector in Q2:

– Solar led with $811 million invested across 26 deals. The number got a big boost from the $150 million raised by solar thermal company BrightSource Energy, and the $129.4 million led by Kleiner Perkins Caufield & Byers in concentrated solar outfit Amonix.

– Biofuels came in a distant second with $302 million across 13 deals. Amyris Biotechnologies is the vanguard in this arena, raising more than $105 million in two separate rounds and filing to go public.

– Smart grid companies bagged $256 million across 11 deals, led by the $165 million raised by Swiss smart meter maker Landis+Gyr. Home energy management system company OpenPeak also brought in a massive $52 million to bring efficiency tools to residential markets.

– Energy efficiency businesses took in $147 million across 31 deals. Clearly the most capital-efficient area of the sector — including mostly software and web-based application makers — energy efficiency got its biggest boost from investments in LED development, including $11.4 million for a startup called Nualight.

Around the world, 19 clean technology companies successfully went public, generating $2.31 billion dollars — an 18 percent increase from Q4 of 2009. Most of these sales occurred in China, with only three in North America. The biggest contributor to the $304 million made from IPOs in the U.S. and Canada: Tesla Motors, which raked in $226 million on Tuesday.

For the most part, the usual suspects in the venture community participated the most this quarter, including Kleiner Perkins, which invested in four rounds, and Khosla Ventures, which invested in three. But the winner, somewhat surprisingly, turned out to be U.K.-based Carbon Trust Investment Partners, with six deals under its belt this quarter.