Solar Trackers Gaining Ground: May Boost Efficiencies by 40%
Image credit: TraxleStrong Growth for Solar TrackingAs recently as 2005, solar systems that adjusted their position to follow the sun, like Johnson and Johnson's 505kw solar tracking array or the Sun Tracker, were seen as exceptions from the norm. But, encouraged by generous government policies and improved reliability, solar tracking arrays are capturing an increasing share of the large-scale market. If their proponents are to be believed, they could improve some solar arrays' efficiencies by as much as 40%. But not everyone is convinced. Jennifer Kho over at Renewable Energy Access offers a thorough and informative analysis of the solar tracker market, exploring the pros and cons, the technologies available, and how some companies have seen solar tracking mushroom in the last few years:
Several companies say they are seeing tracker growth. Miguel de Anquin, vice president of Premier Power, a solar installer in El Dorado Hills, Calif., says that about 70 percent of its ground-mounted commercial projects involve trackers today. That compares to only 20 to 30 percent of a far smaller pool of projects just four years ago, he says. (See image of the solar trackers at the West County Wastewater District implementation in Richmond, CA that were installed by Premier Power, below.)
And in Spain — which overtook Germany as the world's largest solar market last year — tracker projects went from making up an insignificant part of the market in 2006 to perhaps 25 to 30 percent of new projects in 2008, estimates Maria Lahuerta Antoune, international marketing manager for ADES, a Zaragoza, Spain-based tracker manufacturer. (Lead photo, top of page, shows an ADES installation in Spain.)
Kho attributes part of this growth to government policies like Spain's feed-in tariffs or California's solar rebates which encourage producers to obtain as much energy as possible from each individual panel. She also notes that improvements in reliability and efficiency have lead to greater acceptance.
Now I'm by no means an expert on solar technology, but it stands to reason that maintaining optimal positioning would be of great benefit to solar generation, as long as the energy generated is greater than the energy it takes to move the panel, and as long as the system can be kept running without excessive maintenance.
From conversations with various players in the solar field, the jury is still out. I know of at least two folks that have installed solar tracking arrays because they felt it was cheaper to pay for the tracker than it was to install an equivalent number of additional panels. Meanwhile I also know solar installers who say they wouldn't touch the things - arguing that they are one of the most likely components to fail in a system. Kho's article would seem to confirm this divide - with tracker's being seen by many as a higher risk option, but one that can also bring greater returns.
In the end, Kho argues the future depends very much on other trends in the industry:
Of course, trackers aren't seeing universal growth. Some government policies favor rooftop projects over ground-mounted projects, or only offer incentives for projects too small to make most trackers worthwhile, Lahuerta says. (Egon AliOglu, president of Global Interactive Net, disagrees that trackers make less sense for smaller projects, although they are certainly more prevalent in large projects today.)
Trackers also don't make financial sense for the growing number of thin-film solar projects, de Anquin says. Thin-film panels take up more space per watt of capacity, meaning a thin-film project would require more trackers, increasing the relative cost of trackers to the rest of the project, he says. Thin films also capture more diffuse light than conventional panels, so they stand to gain less generating capacity from tracking the sun.
I regularly visit a site with a solar tracker and I must admit there is something beautifully futuristic about the way the huge panels almost silently follow the sun. But I'm guessing that even if trackers are going to continue to make their mark on the renewable energy world, it won't be their sci-fi aesthetics that are the driving force...