Per Capita Davis: Some good news for a change
Spring has sprung and its time for some good news for a change on the climate front.
First, maybe a new approach will help solve the issue of where to locate solar panels. Some people (fewer now) complain that they are unsightly and don’t want them on rooftops. Others oppose massive installations in the desert. And heaven forefend we should put them on agricultural land where they could grow electrons instead of corn.
There appears to be a growing trend towards a location that doesn’t set anyone’s hair on fire: over the water. It’s called “floatovoltaics” and, if you can believe it, even the U.S. Department of Energy is behind it.
A commonly unknown fact is that solar panels decline in efficiency when the ambient temperature gets too hot. They can function in adverse environments, such as the heat and dust of a desert, or in areas with snow, and they can, if constructed correctly, even withstand hurricanes.
Putting them over water, however, can lower the temperature and increase efficiency. So not only do you avoid the “this is a great idea but don’t put it here” argument, you get more electrons for your buck.
Floatovoltaics are not a new idea. There are many efforts in India, for example, to place PV arrays over canals to produce power to run pumps to irrigate fields. And closer to home, neighboring Sonoma County or, more accurately, the Sonoma County Water Agency, which provides water to the residents of the county, experimented with floating solar in a six-month pilot program on a recycled water pond to test the pros and cons of floating solar.
This test is a part of Sonoma Water’s efforts to provide “carbon free” water as well as reaching a goal of 100-percent carbon free for municipal operations.
Tellingly, they were motivated by their understanding that they were already engaged in placing solar pv on rooftops and above parking lots, and were looking for new areas that did not involve ranch lands or agricultural properties; they wanted to avoid the entire NIMBY controversy. The trial produced positive results and the Sonoma County Water Agency is moving ahead on floatovoltics.
But what is happening in the Netherlands ups the ante quite a bit. At least in part as a response to NIMBY resistance to solar panels on land, they are installing more than 73,000 PV panels on a reservoir. And, the panels they are installing are capable of tracking the sun, changing their orientation over the course of a day to maximize exposure to the sun.
It even turns out that sunlight reflected off the surface of the water can also increase the efficiency of the panels. This last fact is cold comfort to a company you may have heard of: Solyndra. It was one of the companies that received government loans intended to test technologies and stimulate the economic recovery after the 2008 meltdown.
Solyndra had a different idea for a solar PV collector. Instead of a flat panel, they produced, just down the road from us in Fremont, a round collector that looked very much like a fluorescent bulb like those you might hang in a shop or grocery store. It was to be installed above a white surface; so that sunlight that passed through spaces between the tubes would be reflected back up and captured, thereby increasing the efficiency of the system.
This type of installation would have a natural market in areas where panels completely shading the ground were not desirable, like nurseries, some field crops or even back yards. The system effectively contemplated “dual use” of land or purpose.
Anyway, it was their misfortune to bring their product to market at exactly the wrong time, as China reduced the cost of their solar panels below what almost anyone could match, putting Solyndra, along with much of U.S. solar manufacturing, out of business.
Back to the topic: floatovoltaics are an intriguing innovation. The system in Holland is built to track the sun, and also to change orientation in response to high winds from storms. Pretty smart.
Somewhat amazingly, at least to this writer who has been driven to deep cynicism about the federal government’s interest in anything other than fossil fuels when it comes to energy, the U.S. Department of Energy is apparently enthusiastically promoting floatovoltaics.
Among its other advantages, the department’s National Renewable Energy Laboratory has noted that floating systems can reduce water lost thorough evaporation. Sort of a two-fer: produce electricity at a location, such as a wastewater treatment pond, that doesn’t gore anyone’s ox, and save water doing it.
In fact, NREL estimates that floatovoltaics could provide up to 10 percent of the nation’s entire supply of electricity, and that’s assuming only about a quarter of the nearly 25,000 human-created reservoirs were used for this purpose.
Perhaps this will motivate renewed discussion of using the canals of the Central Valley water system as sites for modules of solar pv straddling the width of the canal, easily cleaned or replaced, virtually the entire length of the State of California.
— John Mott-Smith is a resident of Davis. This column appears the first and third Wednesday of each month. Please send comments to firstname.lastname@example.org.
Crossposted from the Davis Enterprise
Cool Davis is a coalition of citizens, the City of Davis, and community organizations working to empower our community to reduce greenhouse gas emissions.
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