In Nevada's desert landscape, one of the world's largest solar plants is churning out enough electricity to power more than 15,000 U.S. homes a year. But unlike traditional photovoltaic technology that converts sunlight into electricity, Nevada Solar One relies on technology that makes electricity using the sun's heat.
Receivers from solar-manufacturer Schott are playing a key role in the project. And in late September, the privately held German company revealed it would raise its stake in solar-thermal technology. The company said it is building a U.S. manufacturing facility that will produce both conventional solar panels and concentrated-solar receivers.
Schott is bulking up its solar-thermal production capabilities because it holds the potential to deliver a far cheaper form of solar power to utilities. But truth be told, the approach so far has mostly been limited to small demonstration plants.
So why does Schott, which ties with Spain's Isofotón as the 10th largest solar maker in the world, believe the time is right for solar-thermal? And how will the technology compete with traditional photovoltaic - or PV - systems? Greentech Media sat down with Alex Marker, a research fellow with Schott North America, to find out.
Q: How will PV and concentrated solar-thermal balance out in the future?
A: I think PV is the real option for distributed power and the concentrated is more for utility scale. You can see that in the design of the stuff. You would never put a trough system on your house. Your yard wouldn't be big enough. Whereas the PV is ideal for residential, small commercial applications and even relatively large commercial applications.
Q: Could that change with the advancement and adoption of thin-film solar?
A: There is [a] possibility if you go to some of the advanced thin films that are very efficient. But the issue with those is that the energy storage is still difficult because you are still going from sunlight to electricity. To make even utility scale PV dispatchable, it's going to be a much more challenging issue, financially and technically, than some of the thermal storage.
Q: How will concentrated solar-thermal and PV play out in Schott's own portfolio?
A: In the long term, 5 to 10 years out, I'd say they would probably be almost on par.
Q: Solar thermal went nowhere for years. Why does it make sense now?
A: A lot of that has to do with the fact that a lot of states have RPSs, renewable portfolio standards, which require the utilities to get their power from renewables. To meet the RPSs, a lot of states have to ultimately use solar resources. They will not be able to get enough out of just wind and geothermal to meet their requirements …. You are only going to meet that with concentrated solar power.
Q: Some groups, like the International Energy Agency, have said PV makes sense for large-scale projects (see Solar Desert Debate Heats Up). Why do you think solar-thermal is the way to go instead?
A: Traditional PV would take up more land real estate to get to 50 or 100 megawatts than using concentrated-solar power. [Also,] it's a lot easier to store heat than electricity, so the cost of [energy] storage is cheaper.
Q: What solar-thermal technologies are most appealing?
A: A lot of that will be trough technology, especially in the short term because that's basically a proven technology. It's technically not a high risk. With advances in the performance of things like receiver tubes to mirrors, the performance of the systems is increasing.