Venture-capital numbers released in the past week are sending mixed messages about whether greentech investment is shrinking or growing.

According to a Dow Jones VentureSource report released Saturday, overall venture-capital investment is down while clean technology fundings remain strong.

Venture-capital investment slipped 7 percent to $6.84 billion in the first quarter of 2008, compared with the same quarter last year, with deals falling to 603, the lowest quarterly total since the first quarter of 2005, according to VentureSource.

But clean technologies “continue to attract steady interest from investors,” according to the report. Those technologies, accounted under energy, agriculture and advanced specialty chemicals and materials segments, came to $532 million in 34 deals, on par with last year’s levels.

Numbers from PricewaterhouseCoopers and the National Venture Capital Association told a different story. According to a report released Monday, venture deals reached $7.1 billion in 922 deals in the first quarter, down 8.5 percent from $7.8 billion in the fourth quarter of 2007, and greentech investments also fell.

Cleantech, which those groups categorize as alternative energy, pollution and recycling, power supplies and conservation, dropped about 6 percent from the fourth quarter of 2007 to $625 million in 44 deals in the first quarter of this year. But the quarter saw growth of 51 percent from the first quarter of last year, according to the report.

In an opposite finding, a report from the Cleantech Group earlier this month reported that first-quarter greentech investments declined from the previous quarter, but rose from the year-ago quarter (see Funding Roundup: Dancing on the Edge of a Bubble?). And Greentech Media’s Venture Power Report earlier this month found that greentech investments rose to an unprecedented level in the first quarter, beating all earlier quarters (see Funding Roundup: Greentech Sees $988M in Q1).

In any case, it’s clear that greentech companies – including those in solar power, biofuels, lighting and even tidal energy – are continuing to close deals in the second quarter. Here is our roundup of some of the top deals in the past week:

Solar:

  • Solar-thermal developer eSolar said Monday it had closed a whopping $130 million in funding from Idealab, Google.org, Oak Investment Partners and other investors. This is second time Google.org has backed eSolar, a concentrating solar-thermal startup; the search giant's philanthropic arm already doled out $10 million to the solar company in January (see Google Heats Up eSolar with $10M). eSolar plans to begin producing electricity using fields of mirrors that direct sunlight toward a water tower to make steam, which it then converts into electricity, at a power plant in Southern California this year (click here to see a demonstration)
  • Phoenix-based Stirling Energy Systems has raised $100 million for concentrating solar-thermal technology that uses engines to produce electricity. The deal gives Dublin-based alternative-energy company NTR a controlling stake in Stirling, according to The Arizona Republic. The cash will help Stirling build two Southern California solar farms with a total capacity of 1.7 gigawatts, beginning with a 300-megawatt plant the company plans to begin building next year near El Centro, Calif., for San Diego Gas & Electric
  • Thin-film solar developer Sencera International Corp. said Tuesday it had snagged $3.6 million in funding. The Quercus Trust led the investment. Sencera will use the funding to increase cell efficiency and to support other research and development projects. The Charlotte, N.C.-based company claims it is working to manufacture thin-film solar panels at a cost less than $1 per watt
  • Sungevity, a Berkeley, Calif.-based startup that uses satellite images and proprietary software to engineer solar-electric systems from afar, launched Monday with former Greenpeace campaign manager Danny Kennedy at its head. The company, which hopes to make it easier, faster and cheaper to install solar power, also said Monday that it had raised $2.7 million back in December from investors including German solar company Solon and actress Cate Blanchett
  • Solar installer Real Goods Solar priced its shares at between $10 and $12 each Friday. The company hopes to raise up to $69 million in its initial public offering. Real Goods, a subsidiary of Gaiam, will use $19.8 million of the money to repay its parent company, which sells yoga supplies and environmentally friendly household products, according to the Associated Press. Gaiam will own about 66.7 percent of Real Goods after the IPO.

Biofuels:

  • The U.S. Department of Energy unveiled Friday the three companies selected to receive up to $86 million in federal funding to develop small-scale biorefineries. RSE Pulp & Chemical and Ecofin are eligible for up to $30 million and Mascoma could see as much as $26 million. Expected to be operational within four years, the biorefineries will produce transportation fuels such as cellulosic ethanol and bio-based chemicals and industrial products.
  • Albany, N.Y.-based Innovation Fuels and European Arpadis Group unveiled their joint venture Monday called Innovation Fuels Europe. The newly minted company based in Antwerp, Belgium, will market and distribute biodiesel throughout Europe. Innovation Fuels also announced Monday that it grabbed $15.5 million from Credit Suisse Customized Fund Investment Group, RNK Capital and Lyrical Partners. The United States-based company did not disclose how the financing will be used.

Other:

  • The Asian Development Bank said Thursday it will spend up to $100 million to seed five private-equity funds focused on clean energy in Asia: the MAP Clean Energy Fund, China Environment Fund III, GEF South Asia Clean Energy Fund, Asia Clean Energy Fund and China Clean Energy Capital
  • Nanotech lighting company QD Vision announced Wednesday it had raised $9 million in financing from Highland Capital Partners, North Bridge Venture Partners and In-Q-Tel, an investment firm launched by the CIA in the late 1990s. The funding is part of an anticipated $16 million third round of funding, according to the New England technology journal Mass High Tech. Based in Watertown, Mass., QD Vision claims its technology will help improve the color and brightness of such items as lighting and consumer electronic displays with less power than technologies currently available on the market
  • River- and tidal-energy startup Hydro Green Energy has snagged $2.6 million in its first round of funding. The Quercus Trust led the round for the Houston-based startup, which plans to use 250-kilowatt-capacity turbines to begin generating power on the Mississippi River in Minnesota starting in August, according to the Houston Business Journal.