The future of solar – centralised or local generation?  

RenewEconomy has a look at large scale solar projects in the US and the uncertainty over where the growth will be in future - large scale solar thermal power or smaller scale distributed solar PV installations - The future of solar – centralised or local generation?.

The 392MW Ivanpah solar tower power station is the biggest concentrated solar thermal project in the world. It is also the most visually arresting. It features three huge towers, each 150m tall, surrounded by huge fields of mirrors that will focus the sun’s energy on a receiver located at the top of the tower. Water is boiled to create steam that then drives the turbines. It’s solar generation at a massive scale, made more impressive by its surroundings. Even though it spreads over so many hectares, its size pales against the grandeur of the stunning Mojave landscape.

Ivanpah is not the only solar power station of large-scale being built in this art of the world. To the north, across the state border in Nevada, a 110MW solar tower with storage facility is being built by SolarReserve.

To the west, in the heart of California’s “high desert”, First Solar is nearing completion of a 250MW AVSR solar PV project near Lancaster, while down the road SunPower has begun construction of a 579MW solar PV plant of their own. A little further north, the tables are turned as SunPower puts the finishing touches to its 250MW CVSR project, while First Solar is about to trump it with the 550MW Topaz solar PV project, which is half way through construction.

But even as these massive projects are nearing completion, the question is being asked: Does the future of solar really lie in more of these large scale projects? Even the owners of these huge projects are not so sure.

NRG, the largest owner of generation assets in the US, and part owner of the Ivanpah project, says it is uncertain about the future of such large scale projects, because they are hugely capital-intensive. “These projects are massive, and even though the technology is proven it is very difficult to continually build these in the US, because there are limits to where these projects can be placed,” says Todd Michaels, the head of distributed generation for NRG. “Utilities are fully procured out in the south-west where this technology most appropriate. You are seeing a move to push new solar projects into distribution network. That’s where our CEO David Crane is saying these projects are heading – into distributed energy in general and solar in particular.”

CEO SunPower Tom Werner is building two of these massive projects, but even he says he is not sure where the future lies, which is why he is having his company hedge his bets. “We large scale utility, large and small distributed generation , and rooftop,” Werner told RenewEconomy is a recent interview. “We purposely straddle all three because we don’t know the answer to your question, to be honest. “Here’s how we look at it. The beauty of solar is that it is easy to site, where there is sun. It’s quick to install, scaleable, and you can make it big or small. Those are huge advantages. “So you can though utility problem on its head – you ask yourself, where do I have transmission, where do I have load, and then you can put put solar in it.