Environment & Science

Bill seeks to use renewable energy to boost water supplies

Some of the 24,000 mirrors called
Some of the 24,000 mirrors called "heliostats" at the eSolar Sierra SunTower power plant in Lancaster, California in the Mojave Desert approximately 70 miles (110 km) north of Los Angeles.

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As the state slogs through its fifth year of drought, many water agencies are increasingly turning to alternative water sources to boost supplies -- source like seawater, brackish groundwater and recycled wastewater.

But those need a lot of energy to treat. Now a local state senator wants to use California's growing renewable energy supply to help meet that demand. 

“In the old days I remember we had this thing called Flex Your Power,” said state Senator Bob Hertzberg (D-Van Nuys). “Now at 2 o'clock on that hot August day we have so many solar cells that are popping you actually want people to use energy.”

Earlier this year Hertzberg introduced Senate Bill 919. His idea is to reduce the electrical costs to water treatment plants that create or supplement local supplies of water.

The Camrosa Water District in Ventura County is among those that could benefit. It serves 30,000 customers in and around the city of Camarillo.

Right now, the district imports almost two-thirds of its water from Northern California. Ian Prichard, Water Resources Manager at Camrosa, said the district hopes to reduce that to about a third in the coming years.  

One of the ways they’re starting to do that is through desalination. In 2014 Camrosa finished construction on the Round Mountain Water Treatment plant.

The plant takes salty well water and converts it into about 1-million gallons of drinking water per day.

That water, though, requires a lot of energy to produce. It takes almost two megawatt hours of electricity to get one acre-foot of water out of Round Mountain. This is about three times the amount of power needed to get the same amount of water out of a well that doesn’t need desalinating.

“The cost of electricity is a huge component of running this kind of plant,” said Prichard. “If you can drop the cost of the largest cost component then that's all to the good.”

Herzberg's bill that would lower electricity costs for water producers during certain periods of time -- specifically during times when renewable energy like solar and wind are at maximum production.
"The biggest issue here is everybody bellyaches about the cost of energy, the cost of energy, the cost of energy," Hertzberg said. "Well for the first time we have a real solution that's an environmentally correct solution."
Solar energy provides about 5 percent of California's energy. For wind, it's about 6 percent. Those number are expected to grow under laws that require California to get half its power from renewable sources by 2030.
Steven Kelly is the director of policy for the Independent Energy Producers Association. His group represents non-utility owned power generators. They helped write the legislation.

"We're trying to design a model that would be a win, win for multiple sectors of the economy," Kelly said.
The idea behind the bill is to incentivize water production at times of peak renewable power. Those times often coincide with peak consumer demand for energy overall. Given current pricing structures, industrial customers like water facilities are often charged more during times of peak demand. It's meant to dissuade them from operating during those hours so more power can go to homes. 
The new bill would give local water facilities a break, letting them pay off-peak rates during peak hours.

Many in the solar industry have remained quiet about SB 919. In a written statement, Bernadette Del Chiaro with the California Solar Energy Industry Association said her organization didn’t have a position on the bill.

Del Chiaro, however, said her group would like to see more resources put toward developing storage options for electricity produced by solar. This could come in the form of electric cars, battery units installed in homes or large scale battery plants.

“There's a bunch of tools that we can use to smooth out the peaks and valleys of energy generation versus demand,” she said.

The city of Long Beach is on pace to get one such facility by 2021. It’s expected to be the largest of its kind in the world and will replace an aging natural gas plant.

The idea behind the plant is to allow it to absorb electricity generated by solar energy during the day and release that power during the evening.

Both Del Chiaro and Kelly say the issue of overgeneration is small now, but will likely increase as the state adds additional solar over the next decade.

"The effects of it are starting now,” Kelly said. “But I think the problem looks relatively more significant in five to ten years down the road.”

In the meantime, Hertzberg hopes to see his bill go before the state Assembly before the end of August.