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Zenman Energy is currently developing a low-cost solar steam engine generator in a bid to drastically reduce the installed cost per watt of home solar, with the aim being to help get solar power plants built that will cost less than any other form of electricity generation. With coal at $2 per watt installed, that's a mighty lofty goal, but because the company will be giving away detailed construction plans after the prototype is complete, they hope that their open source model will further improve the design and reduce the cost of the units."Zenman Energy is attempting to create a low cost solar steam engine generator. This generator works by focusing a large surface area of sunlight onto a smaller area. The energy in the sunlight concentrates and produces vast quantities of heat. To increase the amount of energy, we increase the surface area of sunlight. We convert this heat into mechanical energy by boiling water and turning a steam engine. The steam engine will power an electric motor which ties directly into the power grid." - Zenman Energy
The concept of solar steam engines is not new, although most other installations of concentrated solar arrays are quite large. Zenman wants to create a solution for creating grid-connected solar power plants of any size, from residential to utility-grade, at a lower cost than current PV installations.
Right now, the company is building their first prototype, which powers a 10hp motor expected to produce a little over 7 kw. According to Zenman, this size of solar plant would be enough to power a single home (averaged to roughly 29 KWH per day), with 5 hours of sunlight each day generating about 35 KWH per day. But because these are grid-tied generators, this clean energy produced during the day offsets the grid power needed after the sun goes down. The next prototype planned is to be much larger, with more solar collectors and a 100 horsepower motor, producing about 73 kw. Once that goal has been achieved, the company is looking at building a 1MW operational solar steam engine power plant.