Why Isn’t Texas Saving Energy and Water through Solar Floatovoltaics?

floatovoltaics flickrSymbiosis – in which different species have a cooperative or mutually beneficial relationship – is everywhere in nature: honeybees receive vital nutrients from flowers while delivering pollen (male) directly to the female parts of the flower; pilot fish gain protection from predators, while sharks gain freedom from parasites; and dogs protect their owners, while receiving food and shelter. Cited by some scientists as a major driver of evolution, symbiosis has played an important role in the mutual survival of certain species.

Two elements in nature that are also very symbiotic are energy and water: It takes water to produce and distribute energy, while energy is used to treat, pump, and distribute water. This inextricable link is known as the energy-water nexus. Yet, energy and water planners do not treat these important resources as symbiotic “species,” resulting in a lot of waste – something we cannot afford with climate change on the rise.

Floating solar panels atop bodies of water, or the cleverly nicknamed “floatovoltaics,” are a possible solution for both energy and water challenges. The panels help to reduce evaporation of water – critical in hot, dry places like Texas and California – and the water helps to keep the panels cool, increasing their efficiency. Plus, compared to more traditional fuel sources, solar PV requires little to no water to produce electricity. Incorporating more solar energy and relying less on coal or natural gas means greater water savings overall.

Floatovoltaics seem like a win-win solution, but it’s not being deployed on a large scale yet. Some countries and U.S. states have surged ahead in testing this technology. So why isn’t a state like Texas, with big reservoirs, crippling droughts, and lots of solar potential, taking this bull by the horns?

International and domestic floatovoltaic leaders

Several countries are embracing the inventive energy-water solution:

–Japan: The largest floating solar plant in the world is underway at the Yamakura Dam near Tokyo. According to the plant’s developer, it will generate “enough electricity to power approximately 4,970 typical households — while offsetting about 8,170 tons of CO2 emissions annually. This is equal to 19,000 barrels of oil consumed.” That’s an impressive generating capacity, especially considering Japan’s acute energy demand crisis. In 2015, Japan only produced about 10 percent of its own energy and imported the rest. Since the Fukushima nuclear disaster in 2011, Japan has shifted toward the development of more local, renewable energy, but clearly still has a ways to go before becoming energy independent.

Solar is also much less of a water hog. Islands always need to protect water resources, and space for solar panels is limited, so capitalizing on “unused” space above the reservoir makes sense. Simultaneously powering and quenching an island nation’s thirst in the face of climate change is a very smart move.

–England: Europe’s largest floating solar plant is being constructed in the Queen Elizabeth II Reservoir near London, England. In a nice bit of symmetry, the power generated from the panels will provide electricity for the utility’s nearby water treatment facility, helping Thames Water achieve its goal of self-generating one-third of its power by 2020. This is not the first floating solar plant in the U.K., but its size will dwarf the pilot project that was completed previously.

–India: Work is underway for the country’s largest project on Loktak Lake, the biggest freshwater lake in the northeastern state of Manipur. India is also host to a precursor of floating solar: SunEdison India previously launched the Canal Solar Power Project in Gujarat, using the long network of canals across the state to generate electricity from panels that are anchored into concrete blocks on the embankment. Like floatovoltaics, those panels result in less evaporation. In a country struggling with the freshwater needs of its enormous population base, reducing the evaporation rates of the canal water is critical.

And the idea is gaining steam stateside, as well:

–California: Unsurprisingly, California is a leader in floatovoltaics in the U.S. The state’s clean energy subsidies and incentives, pressure from the drought, and an innovative tech sector have all helped this technology find a foothold. The Wine Country has seen the greatest uptake: Both Napa and Sonoma have floatovoltaic systems underway. In Napa, the Far Niente winery (pictured above) installed a system in 2008 that reduces evaporation from the waterway by 70 percent and generates enough power to completely offset the winery’s annual use. Sonoma County’s installation, due to come online this year, is expected to generate power for 3,000 homes, making it the second largest floatovoltaic system after Japan’s.

–New Jersey: Probably a surprise to those outside the solar industry, New Jersey is one of the leading solar states in the U.S., beating out sunny spots like Texas, New Mexico, and Nevada (that’s down to politics, not potential). Consequently, New Jersey is home to a floatovoltaic project at the Canoe Brook Water Treatment Plant, run by New Jersey American Water. The project generates about two percent of the water treatment plant’s power, saving around $16,000 per year.

Why not Texas?

Why isn’t Texas further ahead in the clean energy game? It’s a question I ask myself every day, especially when I think about the water-saving aspects of solar panels, both the floating and mounted kind. It comes down to political leadership on clean energy, which is still a struggle in an oil and gas state like Texas.

At the same time, we are a state plagued by droughts, and every policymaker knows that. Texas is likely looking down the barrel of another drought – developing our prime potential for floatovoltaics could help alleviate future stress. We store a lot of water in large reservoirs, which could easily lend themselves to floating solar panels. Or, we could use the technology on cooling ponds at traditional power plants. In addition to generating solar power next to a grid-connected traditional power plant, this would reduce the evaporation of those ponds, a particularly critical issue in our hot summers.

It’s worth noting the floatovoltaic projects underway in other countries and states all have some sort of policy incentive behind them. We need political leadership to encourage the transition to cleaner, water-saving energy sources. With just under a year before our legislators come back to Austin, here’s to hoping they begin to see the symbiotic relationship between energy and water. The evolution and survival of our species depends on it.

Photo source: Flickr/Thomas Roche

This entry was posted in Energy-Water Nexus, Renewable Energy, Solar. Bookmark the permalink. Both comments and trackbacks are currently closed.


  1. Not buying into it
    Posted March 2, 2016 at 8:15 AM | Permalink

    How does the lack of sunlight penetrating the water affect the biology of the reservoir? In Texas, fishing is a major recreational activity on all bodies of water.

    In order to have one megawatt output from a PV, it is estimated to need five acres of area for the panels (NREL study). This means that significant areas of water would need to be covered for any significant output from a PV. The PV must also be anchored in several locations, which means that the most cost effective option would be to place the panels in coves. These areas see the biggest use by fisherman and the everyday lake users. Otherwise the PV would have to be placed in the middle of open areas of water. This option is equivalent to placing a concrete block in the middle of 635 in Dallas or I-45 in Houston. There is plenty of room to go around, but some people won’t pay attention and run into it which will shut everything down.

    I think this would be an excellent option in areas that see little other use, but are unrealistic in areas where bodies of water are extensively used for other industries like fishing and recreation.

  2. Kate Zerrenner Kate Zerrenner
    Posted March 2, 2016 at 1:50 PM | Permalink

    I understand your concern about covering up the surfaces of lakes, ponds and other natural habitats, but these areas aren’t usually under consideration for floatovoltaics projects. There are vast areas of waterways in which floatovoltaics will have little negative impact on either wildlife or recreation. For example, prime locations include wastewater treatment reservoirs and irrigation canals. There is also research and development being done to reduce the need for much anchoring by having the panels actually float on surfaces. Further, in every case, the needs of the body of water will be considered, and I can’t foresee placing panels in places that are used heavily for recreation – rather it is a way to benefit from currently unused waterways.

  3. Posted March 3, 2016 at 9:30 AM | Permalink

    Good question, why are we so far behind Japan where we have installed over 20 MW of Ciel et Terre Hydrelio floating solar systems including the largest in the world at Umenoki, Japan at 7.75 MW. We just opened a Ciel et Terre USA office in Petaluma CA so it is time for us to catch up with our Pacific Rim brothers. Cieletterre.net

  4. Posted March 4, 2016 at 6:03 AM | Permalink

    Good article, Kate. I’ve written a little about this subject, which fascinates me. Currently living in California, where we have a vast network of canal systems that could be utilized with floating solar, there’s so much possibility for creating energy that’s not yet being considered. Glad you brought this idea forward.

  5. Kate Zerrenner Kate Zerrenner
    Posted March 7, 2016 at 3:07 PM | Permalink

    Thanks for your comment. California has a lot of potential, and there are some smaller projects in development there, ones that could be scaled up if they’re successful. California has also been at the forefront of developing technologies to desalinate water using solar along the agricultural canals in Central Valley. The good news here is that there’s a lot of opportunity – we just need to make sure that our dry states are taking advantage of them!

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