Photos: Clean-tech start-ups swing for the fences

Ocean Renewable Power has developed a wave power system that can generate electricity from changing tides. Unlike many wave power systems that use propellers, Ocean Renewable Power uses a turbine that turns to power a magnet generator, as this model shows.

The company intends to start testing a small-scale version of its generator in Maine later this year and test a larger system in Alaska next year. In addition to tracking its electricity output, it will be monitoring the environmental factors, such as impact on marine life, and how much maintenance and cleaning is required, according to CEO Christopher Sauer. A single full-size generator, which can be combined with others, can make 200 to 250 kilowatts of electricity.