Technology Research Area:

Concentrated Solar

What is concentrated solar power, and what does it have to do with TVA's mission?

TVA is committed to developing new, clean, efficient sources of power. Solar power is one of the most promising alternatives to fossil fuel. TVA has already added photovoltaic solar generation to its power mix and is interested in expanding its involvement into other solar technologies.

Concentrated solar works by using lenses or mirrors to focus a large amount of solar energy collected from a wide area on a much smaller area, greatly concentrating the power of the sun. The sunlight is either focused on photovoltaic surfaces or used to heat a transfer liquid to run a conventional power plant.

The most developed and commercialized concentrated solar technology is parabolic trough generation, which consists of a straight, ditch-shaped array of mirrors that heats molten salt to drive power generation systems.

Whereas the best photovoltaic cells convert about a quarter of the sun's energy to DC electrical power, concentrated solar systems convert as much as 40 percent.

What is TVA doing about it?

TVA is investigating the use of concentrated solar to generate electricity and to produce steam to augment the steam cycle of power generation at fossil plants.

What are the possibilities for concentrated solar technology?

Concentrated solar systems are best suited for clear skies and low humidity, which explains their use in the desert Southwest. In the TVA region, clear skies and low humidity are much less frequent, so adoption of the technology in the region is still in the earliest stages.

The effects on the environment are minimal during manufacture and operation of the systems. Because the systems shade a large area, the habitat for plants and animals could be affected over time.

Since generation of power takes place some distance from populated areas, power storage or transmission or both are necessary to get the most out of concentrated solar. Solar power still has a long payback period, so state or local subsidies are often needed to make solar work.

However, the drive to limit emissions from power generation, the dropping prices of solar photovoltaic panels and the high output of concentrated photovoltaic solar power will continue to drive its development.