For the nerds out there who want to learn fun details of solar technology without taking engineering classes, we have a brief intro to solar parabolic troughs.

Nope — these don’t look like the panels that grace the rooftops of homes and buildings to generate clean electricity. Parabolic troughs are solar thermal technology: they use the sun’s heat to directly generate energy. Photovoltaic (PV) panels take a different approach, using panel materials to create an electric current without utilizing heat. These parabolic troughs, and solar thermal electricity in general, are used in large, utility-scale solar farms.

They function by concentrating heat from the sun onto a receiver pipe in the center of the parabolic curve (see the horizontal grey pipe above). The curved surface allows the system to concentrate heat to 30-60 times its natural intensity, and this heat is transferred to the synthetic oil circulating through the receiver pipe. This heated liquid is then sent through a heat exchanger, producing steam that spins a turbine and generates electricity.

Solar trough predominate utility scale solar plants in the United States, and 2010 actually marks the 25th anniversary of the first solar trough technology implemented domestically. This solar plant in the Mojave Desert achieves daily net efficiencies close to 20 percent.

For a seemingly strange-looking solar technology, parabolic troughs play a fairly significant role in the solar market.