Desalination plants powered by solar thermal are being tested in California in agricultural areas far from the ocean. Water used for crops can be filled with salts, and the problem gets worse over. The Water FX Aqua4 provides clean water from “wastewater, drainage water, runoff, saline groundwater and industrial process water. The remaining brine is concentrated into solid byproducts for resale.” The system is a highly efficient, scalable solar still that produces 30x more clean water than by natural evaporation.
The 392-MW Ivanpah solar thermal plant in California near Primm, Nevada officially goes online today, with a dedication ceremony.
Celebrities include execs from the project’s creators NRG Energy, Bechtel, and Brightsource, and financial backers Google and the Department of Energy’s Loan Projects Office which provided a $1.6 billion loan guarantee. Energy Secretary Ernie Moniz is flying in to do the ceremonial honors. Grammy-nominated rock band The Fray, which used Ivanpah as the backdrop for their “Helios” album cover and a music video, reportedly will be performing.
Crescent Dunes in Nevada, another solar thermal plant, starts commissioning this week with a series of start-up procedures, testing the system slowly before coming online with full power. It stores excess heat in molten salt so energy can be produced at night too.
Ivanpah. One of the few new grid-scaler solar plants, in CA near Primm NV. Credit: ivanpahsolar.com/
Solar thermal power plants can use twice as much water as fossil fuel plants and are generally in deserts. The problem is obvious, water is pumped from aquifers. The primary advantage solar thermal has over solar photovoltaic (which uses practically no water) is energy can be stored for later use. Solar thermal reflects the heat of the sun to a central tower to power steam turbines. Excess heat can be stored in molten salt and used to create power when the sun isn’t shining. This makes power production steadier and more reliable.
Newer solar thermal plants use dry cooling rather than evaporation. However, it is costlier and doesn’t work efficiently on hot days, forcing cutbacks in production precisely when it is needed the most.
One approach to solving this problem is to oversize the cooling system so that it can deliver enough cooling even on hot days. That’s the approach taken by the developers of California’s new Ivanpah solar thermal plant, which is about to start production. But it adds to the cost of an already expensive system.
However, the extra cost is generally about 5% of the total construction cost and reduces water use by 90% over traditional methods.
When California needs extra power, it generally imports hydropower from the State of Washington. This year though, a bit ominously, not only is there a California drought, the Pacific Northwest is also short on water. This means less hydropower for everyone.
Since 1989, hydroelectric dams have accounted for varying portions of electricity generated within California, from 11% in 1992 (reflecting a low water year) to a high of 28% in 1995 (a high water year).
Absent output from in-state hydroelectric resources, CAISO [California Independent System Operator] has tended to import more power from neighboring regions as well as increase output from thermal sources of generation. Much of the imported power comes from hydroelectric dams located in the Pacific Northwest, which is also experiencing low water supply.
An ambitious plan to build a 600 MW pumped hydro facility in California has gotten past a thicket of interconnect issues. If built, a hydroelectric facility will create energy and pump water uphill during off-peak hours from Lake Elsinoreto to a 100 acre reservoir created in an existing canyon. When additional power is needed during peak water, water is released, powering turbines, creating electricity almost instantly. Pumped hydro is one of the oldest methods of stored power.
You will of course note that a reservoir must be built in an existing canyon. NIMBYs will not like this. The project has already taken years. Now it will do three years of feasibility studies then perhaps get the final permit. Building new energy generation facilities in California whether renewable or otherwise, takes years, sometimes decades.
Quinones, which are found in rhubarb and elsewhere, can be used to create inexpensive, efficient batteries suitable grid scale renewable energy storage. This is a potentially huge development. Production of renewable energy by nature is variable thus storage is essential for renewable energy to be reliably created at mass scale without causing problems for the grid. Rhubarb batteries could be the solution!
[The batteries] are water soluble, which means you can set up large, inexpensive tanks to hold electricity, instead of having to engineer solid-state batteries like ones found in cars. These “flow batteries” would be capable of storing one kilowatt hour of energy using chemicals that cost $27, a third of the price of existing systems.
Salt-tolerant desert plants, halophytes, can be grown on non-arable land using seawater, and processed to create biofuel. Wow. Even better, this is just one part of a process that grows fish and shrimp and mangrove biomass. This astonishing process is being developed by the Sustainable Bioenergy Research Consortium in Abu Dhabi.
Frequency regulation keeps the electrical grid in balance between supply and demand on a second-by-second basis. Gas turbines often do this now. However, researchers at the National Renewable Energy Laboratory have found that wind turbines can do the same by changing the pitch of their blades. Thus, a wind farm could perform a crucial service and generate more revenue by delivering and dropping power output at precisely the right moments.
“Because the grid values these services so much, [wind farms] can actually earn more money by curtailing and providing services than if they’re providing energy,” he said.
For example, there are times in the middle of the night when wholesale energy prices are negative because there is excess wind power. At those times, frequency regulation services would be more valuable than providing energy.
The technology for wind farms too do this already exists. However, it has yet to be implemented on a massive scale. Once it is, wind farms could provide frequency regulation faster than fossil fuel plants.
Washington DC plans to process 120 tons of solid waste a day into natural gas to power a wastewater treatment plant. Once built it will save $10 million a year in electricity costs, reduce carbon pollution, and keep the plant running in case of power outages, a triple win indeed.
“In terms of climate readiness, it doesn’t get any more basic than protecting water,” said Fillmore. “And D.C. Water is really leading the nation in making the most of the opportunities preparing for the future , to become better at what they do.”
Imergy Power Systems is introducing innovative, low cost batteries that charge during off-peak hours and can store locally-produced renewable energy. A group of forty homes could share a single Imergy battery system, storing solar power during the day then using it at night. The batteries can also recharge at night when utility rates are lower and can be used in telecom, banking, railway signaling, highway infrastructure, and stabilizing the grid.