Reflecting On Solar Towers

Solar panels are not an unusual sight as more of us search for carbon-free energy solutions. However, solar towers, while having been in development for forty-plus years, are more elusive even as they are being considered to replace traditional, fossil-fuel burning utility plants. If you have never seen a solar tower—currently there are only about a half dozen in the world, two of them in the United States—check out our video below for a sky-high view of one spotted by Force For Good founder, Jonathan Sprout, on the U.S. West Coast.

The basic design includes an array of mirrors, called heliostats, set around a large tower. The heliostats are computer controlled, moving continually throughout the day to best position themselves to reflect the sun’s rays toward a receiver atop the tower. The concentrated solar power (CSP) heats a liquid-salt solution which is used to create steam. The steam in turn drives turbines that make electricity. A useful way to blow off a little steam, right?

The environmental advantages of CSP systems, according to an article in Mother Nature Network, are impressive: “Compared to fossil-fuel burning plants like coal or natural gas, there's no air pollution, water pollution or greenhouse gases typically created in the energy generation process.” But these systems have disadvantages, too. “There are some emissions created in building a solar tower, just as there would be in another type of power plant, since materials have to be moved to the location and built, all of which requires energy, usually in the form of fossil fuels… Some toxic materials are used to make the components of the plant (in this case, photovoltaic cells).”

The local ecosystem is effected if the system uses water for cooling or cleaning. Biodiversity is impacted not only when land is cleared to build the power towers but the concentrated heat kills birds and insects in its path so mitigation measures must be followed. Finding ideal areas are a challenge as flat and dry locations with minimal wind is most efficient. And of course, you need a lot of sun. “Solar towers are often constructed in desert landscapes, which by their very nature are somewhat fragile, so special care must be taken in siting and construction,” states the Better World Solutions website. But as the world moves towards renewable energy, we may see more solar towers in our travels.

You can read more Here and Here

— Leslie Chew & Hillary Black, Force For Good