The six winners for this year’s California Clean Tech Open Awards were announced last Thursday at the Palace of Fine Arts in San Francisco, including a high-performance, green diaper and software for energy efficiency management.

All the contestants were early-stage startups. I didn’t talk to a company that wasn’t still self-funded (excluding the winners, who now have $50,000 in cash and $50,000 in credit for professional services). But if past winners are anything to go by – such as Cool Earth Solar, Aurora Biofuels, and GreenVolts – some of these companies should go on to snag venture backing and make a serious run at profitability.

Here are the winners:

Air, Water & Waste Award: San Francisco-based Over the Moon Diapers - makes high performance, consumer friendly diapers that are industrial wash compatible and can be laundered by diaper services.

Energy Efficiency Award: Viridis Earth - makes a simple retrofit product to save 20% off the electricity demand of air conditioners, often paying for itself in one year.

Green Building Award: Los Altos Hills-based BottleStone - manufactures ceramic stone surface material made of 80% recycled waste glass.

Renewables Award: Mountain View-based Focal Point Energy - offers solar hot water and steam generation for industrial applications.

Smart Power Award: Santa Clara-based Power Assure - makes on-demand energy efficiency management software for data centers.

Transportation Award: San Francisco-based ElectraDrive - offers rapid, inexpensive adaptation of existing vehicles to electric drive or extended-range electric drive trains.

These guys weren’t winners, but I think they hold promise:

Foster City-based Solar Red – cuts the cost of solar installation in half with its proprietary mounting technology.

Redwood City-based Ground Source Geo – installs shallow geothermal systems using licensed technology for building heating, cooling and hot water solutions at costs lower than incumbent technology.

Clean Tech Open is a Palo Alto-based nonprofit that promotes clean tech businesses in the San Francisco Bay Area.