Is the sun setting on solar thermal technology in the American desert?

Shaking up an already-volatile Big Solar market in the United States, German developer Solar Millennium announced Thursday that it would sell its 2,250-megawatt pipeline of projects to another German company that plans to replace the solar thermal technology with photovoltaic panels like those found on residential rooftops.

The four projects – three in California and one in Nevada – were to have been built by a Solar Millennium joint venture called Solar Trust of America and deploy huge arrays of long parabolic mirrors. These solar troughs focus the sun on tubes filled with synthetic oil that are suspended over the arrays. The hot oil is used to create steam that drives an electricity-generating industrial turbine.