In California’s Central Valley, the Plan to Build More Solar Faces a Familiar Constraint: The Need for More Power Lines

California’s San Joaquin Valley, a strip of land between the Diablo Range and the Sierra Nevada, accounts for a significant portion of the state’s crop production and agricultural revenues. But with the state facing uncertain and uneven water supply due to climate change, some local governments and clean energy advocates hope solar energy installations could provide economic reliability where agriculture falters due to possible water shortages.

In the next two decades, the Valley could accommodate the majority of the state’s estimated buildout of solar energy under a state plan forecasting transmission needs, adding enough capacity to power 10 million homes as California strives to reach 100 percent clean electricity  by 2045. The influx of solar development would come at a time when the historically agriculture-rich valley is coping with new restrictions on groundwater pumping. Growers may need to fallow land. And some clean energy boosters see solar as an ideal alternative land use.

But a significant technological hurdle stands in the way: California needs to plan and build more long-distance power lines to carry all the electricity produced there to different parts of the state, and development can take nearly a decade. Transmission has become a significant tension point for clean energy developers across the U.S., as the number of project proposals balloons and lines to connect to the grid grow ever longer. 

Existing lines are not enough to accommodate the spike in large clean energy installations, planning new transmission has lagged and regulators have struggled to keep up with studying and processing all the projects looking to hook up to the grid.

“It’s undeniable that we do need major funding for transmission buildout in California, and frankly, the West, to meet our clean energy goals,” said Dian Grueneich, a former commissioner on the California public utility commission. “The issue is where, how much, when, et cetera, … It’s probably the most complex area there is.”

Compared to other regions, California has been relatively proactive in assessing the grid needs of a decarbonized future, said Rob Gramlich, founder of consulting firm Grid Strategies LLC. But there’s still much work to do. 

“It’s a systemic problem across the country. We have interconnection queue process problems in most regions,” said Gramlich. “The problem is more actuely felt in any region that is going faster on the energy transition. And California is second to no one on the pace and ambition of its clean energy transition.” 

That challenge could cause particular difficulties in regions of California expecting a big scale-up in renewable energy, like the North Coast, where offshore wind developers are planning projects, or areas of the Central Valley eyed by solar companies and facing a potential downturn in the water available for crops. 

‘Short of Water’

In coming years, more land in California once used for agriculture could host solar. In 2014, the state approved the Sustainable Groundwater Management Act, an effort to reduce over-pumping from aquifers that had caused land in certain parts of the state to sink. The law requires local water managers to submit plans to the state that demonstrate how they’ll keep industries and people from pulling water out of underground stores more quickly than it can be replenished.

California farmers get water for their crops via a combination of underground supplies and diversions from reservoirs, lakes, and other stores managed by the state and the federal Bureau of Reclamation. The new groundwater regulations, combined with climate change and other environmental regulations, could lead to a 20 percent drop in annual average water supplies in the San Joaquin Valley by 2040, according to a February analysis from the Public Policy Institute of California (PPIC).

“We’re not short of land, we’re short of water,” said Jon Reiter, founder at Cavalrei, a consulting company focused on agriculture, solar, and water, and a grower of fruit and nuts in the Central Valley.

Up to 900,000 acres of farmland may be idled, resulting in the loss of 50,000 jobs. PPIC analysts have suggested solar as a potential way to fill that economic gap, while helping the state meet its clean energy goals. 

California would need to increase  the amount of large-scale solar it installs each year by 60 percent through 2035 to meet requirements under a climate plan the California Air Resources board published last year. The San Joaquin Valley is viewed as a prime location for some of that development, said PPIC research fellow Andrew Ayres.

The Transmission Challenge

An Inside Climate News analysis of California solar power plant data already shows 243 operating projects in the San Joaquin Valley. The majority are sited in Kern County, known for its oil and gas development and one of the state’s top agricultural counties in terms of revenue. Of the solar projects actively awaiting interconnection to California’s grid, 399 out of 450 solar projects are also located in San Joaquin Valley counties, according to a list from the California Independent System Operator, which runs the state’s grid.

Some of those projects will not get built, because of challenges connecting to the grid, inability to find someone to buy the power, or any number of other issues that can crop up in the development of renewable energy. But demand for access to power lines is already outpacing supply, said Deborah Builder, senior vice president of development at large-scale solar and storage developer Avantus. The company has eight gigawatts of San Joaquin Valley solar projects in California interconnection queues. As more and more clean energy projects have cropped up in recent years, developers have found it increasingly difficult to find land with access to adequate transmission capacity, she said.

Developers look for available transmission because they don’t want to finance it themselves, which adds to a project’s costs and can make installations unviable. Difficulties with connecting projects to the grid is “the number one project killer,” said Lucy Bullock-Sieger, vice president of strategy at Lightstar Renewables, a New York-based community solar development company that is looking to site its first projects in California. (Community solar projects usually provide electricity locally and connect to distribution lines that ferry power shorter distances, but Bullock-Sieger says those companies care about transmission challenges because of how they impact the overall grid).

“We always anticipate interconnection challenges,” she said.

The state is aware of the difficulties. In 2016, when the San Joaquin Valley was host to just 120 solar projects, a team at the University of California, Berkeley analyzed 9.5 million acres in San Joaquin Valley counties to identify “least-conflict” sites for building new renewable energy. The analysis focused on land without high agricultural value—due to water constraints and other factors—and that didn’t contain Tribal  cultural resources. 

The project found more than 200,000 acres that fit the criteria. But transmission lines stretching to the areas the study identified posed a “key barrier” to building in the region, according to Ethan Elkind, an author of the report and director of the climate program at the Center for Law, Energy & the Environment at the UC Berkeley School of Law.

In transmission years, the Berkeley study may as well have been carried out yesterday—projects can take a decade to develop. But energy experts say plans need to migrate from paper to action in the extremely near-term if California is to to fulfill its clean energy goals using large projects that require electricity to travel long distances.

“Given how long transmission usually takes, you would think some of that 20-year stuff would be starting to show up in the 10-year plans,” said David Marcus, a private energy consultant in California. “Not very much of that has happened.”

In the next two decades, California needs to spend an estimated $30.5 billion on transmission development, according to the 2022 outlook report from the state’s grid operator. This outlook could change as energy plans do; the state is also in the midst of determining how much of its electricity demand will be met with small, spread out solar projects versus large projects that require transmission, but both will be needed to meet climate goals. 

Groundwater managers have until 2040 to balance underground water stores. The state has until 2045 to meet its clean energy targets. Ayres at PPIC said the state can embrace that “policy synergy” to ease the economic impacts of groundwater rules by considering how clean energy can benefit agriculture-focused counties. 

California agencies that work on transmission planning could consider where land is likely to come out of crop production in future plans, according to PPIC analysis, and the state could ease certain tax constraints that may keep farmers from transitioning land from crops to solar. But transmission planning—and action—needs to happen soon.

“These processes can be slow,” Ayres said. “If we’re serious about meeting our renewable energy goals, we need to speed things up.”