America’s Southwest is running out of water. Reservoirs are drying up, and our population continues to grow. Our cities, our high-value agriculture, our environment and our future all depend on water resources we don’t have. One abundant resource the Southwest does have is sun. What if we could create a climate-proof watershed by using the Southwest’s plentiful sunshine to create new, fresh water? Using solar osmosis, we can.
Solar osmosis is a process that combines renewable energy with reverse osmosis. Solar energy is used to power a desalination plant that filters the salt out of ocean water to produce new, fresh drinking water.
The Water Issue
For decades we staked our growth and future on having water from the Colorado River. We now face drought, climate change and shrinking supply. Lake Powell and Lake Mead, primary reservoirs on the Colorado River, are near record low levels. Reduced flows and lower allocations are imminent.
With a growing population and shrinking water supplies, we have a crisis. We need a solution. Our prosperity, our food supply, our very way of life depend on finding that solution, and finding it soon. We need a solution that protects our environment, economy, and way of life.
Weather records say our drought will get worse; climate models agree. Dams and pipelines do not produce one drop of water. Conventional water projects just move water toward money and push the drought off on farmers, fishes, forests and poor people. Water conservation is essentially putting a Band-Aid on the problem, rather than attacking the problem directly. It’s time to talk about real solutions to our water crisis, not just Band-Aids.
There is an ocean of water – the Pacific – in our front yard. Just take out the salt. It has been practical for half a century and small desalination plants are here today – like the new Poseidon Reverse Osmosis Desalination Plant in San Diego. But water from small-scale desalination is expensive, and without careful planning desalination plants can damage the ocean.
We can do better. We can produce some new, fresh, clean water. We can protect all those important things that depend on water. But we need to think creatively, we think big picture.
Environmentally sound, economically viable desalination means taking advantage of existing infrastructure, building bigger plants, using renewable energy and protecting the ocean. If we do this right we can save our environment, enhance our prosperity and protect our culture from the drought and climate changes bearing down on us. So how do we begin?
Energy produced by a solar farm sent through the power grid to a reverse osmosis desalination plant will produce enough fresh water each year to cover the solar farm to the height of a 6-story building! Think about that. Solar farms powering desalination plants generate twice the water per acre of the world’s wettest rainforest.
Over the coming decade 300,000 acres of irrigated Central California farmland will be removed from production due to naturally high amounts of selenium and boron in the soil. Solar farms on just this area of disused farmland would produce more fresh water than the Colorado River.
Solar electricity powering desalination delivers reliable water, unaffected by drought or climate change. This is a true climate proof watershed to meet our water needs.
Solar Osmosis at San Onofre
We might start with the decommissioned San Onofre nuclear generating plant. While this plant is done generating electricity and its reactors are permanently shut down, the seawater cooling system is still there, and of course there are a great set of power lines connecting the site to the grid. A desalination plant using the existing seawater intakes would produce 1.1 billion of new fresh gallons per day – as much water as Southern California cities take from the Colorado River. It only takes a short pipeline to the Metropolitan Water District (MWD) to distribute this water throughout Southern California.
Powered by solar electricity, and using a seawater inlet and discharge system that already meets environmental regulations, there will be minimal environmental impact. And when grid demand exceeds supply, the desalination plant can be throttled back, and the energy diverted to the grid, so the project backs-up both our water supply and our energy grid.
Once MWD’s Colorado River water is replaced with new, fresh water from desalination, it can be swapped to other Colorado River users. No additional plumbing needed.
Nobody has to give up water they have now so it can be moved somewhere else. And, compared to old-style storage and pipeline projects, large scale desalinated water will cost less.
We call this combination of renewable energy and reverse osmosis desalination “Solar Osmosis”. It’s the way we can produce additional, fresh, clean water instead of fighting over our dwindling natural supply. But, to do this right we must work together, and that may be the hardest part.
The solution to drought is more water – simple as that. Turning sunshine we have into water we need is a vision for sustaining the environment, agriculture, cities and vibrant growth of the American Southwest in the face of drought and climate change.