Flower Power: Solar tulip provides 24/7 electricity

Form meets function at solar plant. Sun drives turbines by day, biogas takes over at night. Artistic look, expandable design geared for communities, factories. Saves water, too.

Form met function in southern Spain earlier this month, when Aora Solar Ltd. fired up a prototype solar plant in which sculpture-like tulip towers help generate electricity 24 hours, with minimal use of water.

Aora is gearing its artistic-looking solar tulip towers towards small utility-scale deployments for communities and factories that would add towers as they add manufacturing capacity, thus minimizing upfront capital costs.

The solar tulips work on a novel form of concentrated solar power (CSP). Conventional CSP uses sunlight and mirrors to focus heat on a fluid that creates steam and drives a turbine. Aora's technology does not use a fluid. Rather, it positions its mirrors so that sunlight focuses on pressurized air in the 35-meter (115 feet) tulip tower, raising temperatures to 1,000 degrees C (1,832 F) and creating a hot pressurized gas that drives a turbine.

The hybrid design switches to another fuel, such as biogas or natural gas, at night. Click on the video below to see how it works.

"One major discriminator of our system is minimal use of water (this being an air turbine), which is extremely important as many of the potential locations for our systems do not have water to spare," Aora's chief technology officer Pinchas Doron told Cleantechnica.

"This was developed for use in desert environments where you have the most sun and the least water," Aora CEO Zev Rosenzweig said in a Bloomberg report. The story paraphrased him as saying, "By using air rather than the steam turbines most other solar-thermal (CSP) plants have, Aora reduces the plant's water consumption to less than 230 liters (61 gallons) a megawatt hour compared with 3,000 liters (792 gallons) for a steam plant."

The modular approach contrasts to the large scale CSP plants that companies like Brightsource and Abengoa are building, with capacities of hundreds of megawatts. The Aora modules cost about $550,000 for a 100-kilowatt installation, Rosenzweig told Bloomberg, noting, "I gain efficiencies by building a small, simple plant over and over again." He said he is discussing a possible $555,000 installation with a California architect, for 60 homes.

Rehovot, Israel-based Aora (pronounced like "aorta" without the "t") earlier this month connected a prototype tulip plant to the grid in Almeria Spain, a desert area.

Architect Haim Dotan told Bloomberg he envisions installations in which each tulip tower is painted a different color. We'll have to see whether this idea flowers.

Images from Aora

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This post was originally published on Smartplanet.com