A few days ago – April 3 – I wrote here about the history of energy prices. In that post, I mentioned that many of the alternative energy plans we hear about today actually have their roots in our previous experience with escalating oil prices (ca 1975-1980).
Solar, in particular, had made a great commercial start before plummeting oil prices in the early 1980s pulled the economic rug from beneath the blossoming alternative energy marketplace. If you look closely, for example, it’s still possible to see 1979 vintage solar panels on rooftops in sunnier parts of the country. On a larger scale, solar-to-steam-to-electricity plans were on drawing boards around the world – utilizing acres of mirrors focusing sunlight on a central receiver / generator tower – and a demonstration unit was actually built in California.
Today, the solar emphasis seems to be on photovoltaics, converting sunlight directly to electricity. And indeed, the science and economics of photovoltaics have improved greatly in the past few years. However, solar-thermal technologies – despite being decidedly less sexy than photovoltaics – deserve to remain high on the list of solar priorities. Advantages include …
– For the homeowner, solar-thermal systems are relatively simpler and considerably less expensive than solar-to-electricity systems
– Storing heat (in a hot water tank, for example) is a lot simpler and less expensive than storing an equivalent amount of energy as electricity
– Photovoltaic schemes require complex and expensive control systems to interface with the public grid or your home appliances
And, lest I appear one-sided, solar-thermal schemes suffer a significant shortcoming too …
– Upper temperatures are limited (without substantial additional investment in complex and expensive concentrator and control apparatus). Space heating is OK, along with some modest industrial processes, but more ambitious energy processes require higher temperatures than conventional (flat plate) solar collectors can achieve.
Regardless of the approach – solar thermal or photovoltaic – I have this nagging worry that solar energy history may be about to repeat itself, with plunging oil prices removing all the economic incentive for alternative energy development.