Solar thermal is an attractive renewable energy source. Like other solar energy sources, it works, but is often not economically viable compared with established sources, such as coal. With rising energy costs and environmental concerns, there is increased interest in solar today.
The design above is a modern, reflective parabolic dish from Stirling Energy Systems. The dish produces about 25 kW, enough for about 10 homes in the US. This video on YouTube has more details. This video shows a small scale Stirling engine operating on solar power, similar to the full scale dish. Based on data from a large installation, it looks like 4 of these large dishes pictured above can fit in one acre, so that’s 100 kW/acre. The United States consumes about 440 GigaWatts. Roughly 18 million of these units spread over 6875 square miles would satisfy the entire US electric power requirements. That’s about 6% of the land area of Arizona, one of the two states with high solar insolation. It could be built using only 5.7% of the Sonoran desert.
The US congress is currently debating an economic stimulus package of $150 billion. If all of this money was used to build a solar array and each collector could be installed for under $50000, the power output would be equivalent to 44 Hoover dams, or about 20% of US electric power consumption. At current market prices, such an array could pay for itself in under 4 years. After that, the array could yield as much as $38 billion per year in gross revenue.
Of course, transmission of this power from the deserts of the Southwest to where it’s needed is a challenge, but it’s something to think about.