How we could build the worlds largest urban solar farm in the middle of LA
You may remember, as I did, the viral images of 96 million plastic shade balls being dumped into LA’s open-air reservoirs in 2015. Around six months ago I found myself walking past one of those previously ball-covered, now-castrated reservoirs, and it sent me down a rabbit hole.
If we needed to cover the reservoir for some reason, I wondered, wouldn’t it have been better to cover it with something other than plastic, like solar panels? After doing some research the answer was an emphatic yes. It turns out floating photovoltaic systems (FPV) are very much becoming a thing and are one of the most exciting developments in the solar world right now.
Water is awesome for solar panels
It’s not exactly rocket science in terms of complexity level. You take a solar panel, put it on something that floats, and bingo. Whilst this is obviously an oversimplification of an FPV system… it’s not far off the truth. The simplicity of the idea relative to its depth of benefits is what makes floating solar so promising.
A valuable source of space
One of the biggest problems with regular, vanilla land solar is competition for land use. Competition with other land-hungry industries such as agriculture results in higher land costs for solar. Floating solar, on the other hand, unlocks an opportunity to utilize extremely cheap space that otherwise can’t be utilized.
Reducing loss from energy distribution
Competition for land means solar is typically pushed out to remote areas far away from where it’s eventually consumed. When electricity travels through a cable, it will lose some of its energy in an effect known as ‘line loss’. The Energy Information Agency (EIA) has estimated that the US averages 5% line loss which can easily double during hot weather. Floating solar creates opportunities to build utility-scale solar projects closer to where it’s being consumed, thus reducing the impact of line loss. This also comes with a handy cost reduction in energy distribution infrastructure
Water cools panels improving efficiency
The most talked about advantage of floating solar is the cooling effect of the water which creates an increase in energy efficiency. Heat loss is the escape hatch of a ton of potential energy and starts happening at temperatures as low as 77 degrees Fahrenheit. A research paper published by the Institute of Energy Technology in Norway has confidently reported increases of 5-6% although others claim efficiency improvements of up to 15%.
Solar panels protect the water
The benefits of floating solar are mutual. Whilst the water provides great opportunity for producing energy, the shade from the solar panels help protect the water from a range of problems, all caused by exposure to excessive sunlight.
Preventing bromate contamination
Bromate, which is a suspected carcinogen, forms as a result of exposure to excessive sunlight. Two open air LA reservoirs, including the Silver Lake Reservoir, needed to be drained in 2007 due to Bromate contamination. As reported by the LA Times this meant that 600 million gallons of water had to be dumped in the midst of a drought. Shade provided by the solar panels help reduce the potential for this to occur.
Preventing algal blooms
Algae blooms are a common problem in bodies of water all over the world, caused by a combination of conditions including excessive sunlight. They are especially problematic in bodies of drinking/irrigation water as they can be toxic, turn the water green when left unchecked. This is what most likely happened to the Silver Lake Reservoir in 2018 when it turned green and local residents reported a strange smell
Reducing water evaporation
Droughts are becoming more common and severe in many places across the world. California for example has had six droughts that lasted 4+ years in its entire recorded history and two of them came in the last 35 years. Los Angeles’s reservoirs alone lose hundreds of millions of gallons of water to evaporation each year.
Building the world’s largest urban solar farm in Silver Lake
Floating solar is not just a clever use of space - it can also generate serious amounts of power. The Silver Lake Reservoir, estimated based on the performance of the FPV facility in Healdsburg Northern California, could be home to over 60MW of installed solar capacity. To give you an idea of just how impressive that is - the DOE defines medium-scale hydroelectric plants as having capacity of 10MW to 30MW and large scale as 30MW+. A more modest version of the project, covering only 15% of the otherwise unused reservoir, would provide 10MW.
Aside from open air water reservoirs, there are plenty of other creative opportunities for co-locating floating solar. Today, the largest FPV utility in the United States resides on a wastewater treatment plant, whilst other companies are experimenting with offshore floating solar projects. One paper published by the European Comissions’s Joint Research Center estimated that covering 1% of the surface area of a hydroelectric project could double its capacity and utilize the existing infrastructure. Maybe there is a space near you that could provide a loving home for clean, renewable energy generating floating solar panels.
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