Cars and batteries have been on investors' minds lately. With major carmakers due to start selling plug-in hybrid electric cars by 2010, startups have sprung up to take advantage of this new market.

The inaugural Plug-In 2008 conference in San Jose, Calif., last week saw Google.org, the investment arm of the search giant, announcing its investments of $2.75 million total in two companies: battery maker ActaCell and electric-car maker Aptera Motors (see Move to Greener Cars Accelerates).

Aptera Motors, a Carlsbad, Calif., company that is developing a three-wheeled electric car, raised $24 million from investors that also included Idealab, Esenjay Investments, the Simons Family and the Beall Family Trust (see Aptera Scores $24M to Produce Electric Ride).

ActaCell, based in Austin, Texas, raised $5.8 million  for its first round of funding. Aside from Google.org, the company's investors include DFJ Mercury, Applied Ventures (the investment arm of chip-equipment maker Applied Materials) and Good Energies. The company is developing lithium-ion batteries for plug-in hybrid electric cars.

Developing suitable batteries for electric cars is a major challenge. Toyota Motor's Prius uses nickel-metal hydride batteries, but the automaker and many of its competitors are betting on lithium-ion batteries as the proper energy-storage devices for their future cars (see Toyota Drives Towards Greener Fleet).

Read on for more funding news:

PRIVATE:

Carbon Trading:

  • Carbonetworks, which has developed software to track and manage the greenhouse-gas emissions of individual organizations, raised $5 million from NGEN Partners. The company, based in British Columbia, Canada, said it has more than 180 customers in 23 countries.
  • CarbonFlow, based in San Francisco, raised $2.9 million from Clean Pacific Ventures, OVP Venture Partners and Meridian Energy. The company is developing software for the growing market of trading greenhouse-gas emission allowances.

Agriculture

  • Athenix, which is developing genes, proteins and microbes for agricultural and chemical companies, raised $10 million from Hunt Ventures, Intersouth Partners and Polaris Venture Partners. Some of the enzymes and genes from the company, based in Research Triangle Park, N.C., are used to convert biomass into ethanol.
  • Performance Plants, which is engineering hardy seeds for crops that can resist extreme heat or cold, raised C$13 million ($14.79 million) from Ceres Global Ag and Eastwood Capital. The Canadian company is developing both food crops and nonfood crops, such as switchgrass and hemp, for making biofuels.

Other

  • Marblehead, Mass.-based Deerpath Energy, which is developing small-wind turbines, raised $3.5 million from RockPort Capital Partners. Unlike the turbines used in large wind farms, Deerpath's turbines are much smaller and are meant to be installed on the side of the street or in the backyard of a home (see Small Wind Hits an Updraft).
  • G24 Innovations, which has developed dye-sensitized thin-filmsolarcells, raised $30 million from a fund called 4RAE, which is being established in Luxembourg by Eyal Ofer and Marcel van Poecke. Only last month, the Cardiff, Wales, company said it had raised $20 million from Morgan Stanley Principal Investments in June.

PUBLIC

Solar

  • Rexnord Holdings, based in Milwaukee, aims to raise up to $750 million in an initial public offering. The company makes components for power-transmission networks and water-management systems.
  • GT Solar (NSDQ: SOLR) raised $500 million through an initial public offering and its debut on the Nasdaq. The Merrimack, N.H., company makes equipment for producing silicon, wafers, solar cells and panels (see GT Solar Goes Public).
  • Trina Solar (NYSE: TSL) raised $138 million by selling convertible senior notes. The Chinese company plans to use the money to expand its manufacturing of silicon ingots, wafers, solar cells and panels.

FUNDS:

  • General Electric (NYSE: GE), in Fairfield, Conn., has agreed to invest $50 million into an Abu Dhabi cleantech fund and start a technology center in the  United Arab Emirates city. The Abu Dhabi government's Masdar initiative, formed to manage cleantech projects, started a joint venture with Spain's Sener Grupo de Ingenieria in March to build and operate solar-power plants (see Masdar Heats Up Concentrating Solar).
  • Tridos Renewabless Energy Fund raised £10 million ($19.85 million) to invest in cleantech projects in the United Kingdom. The public company, set up by Triodos Bank, has invested in wind farms and hydroelectric projects.