SolStor Energy will combine CSP+TES – delivering solar at night, complementing PV in the new 100% renewable grid
A team of industry experts have joined together to form SolStor Energy, a new US development company to deploy concentrating solar power (CSP) with thermal energy storage (TES) to supply energy from the sun at night. SolStor focuses on developing concentrating solar power configurations designed to complement PV by primarily delivering electricity after-dark from thermal energy storage.
Three members of the SolStor Energy team have separately been awarded the SolarPACES Lifetime Achievement Award for their accomplishments in CSP – Fred Morse (2013), David Kearney (2018) and Xavier Lara (2022).
“We see the several large and growing markets for nighttime energy, so the need is there. And state and federal incentives are there to facilitate projects. Since we know what is needed and we know how to build CSP plants, we decided to form a CSP development company,” said Morse, a longtime CSP expert at the DOE, Morse Associates, Abengoa, and now the Founding CEO of SolStor Energy.
Earlier generations of CSP in the U.S. have been driven by different market conditions. The first generation, in the 1980’s and 1990’s, was largely influenced by the oil embargo of the 1970’s and the country’s ambitions towards energy diversity and energy independence from outside energy sources. At that time, electricity from CSP was cheaper than from photovoltaics. So the first projects at Kramer Junction and Daggett in California were CSP,” explained David Kearney.
The second generation of CSP plants, in the 2000’s and 2010’s, was spawned from state-driven Renewable Portfolio Standards (RPS) which required relatively small percentages of energy to come from renewable energy resources. “By the time this next generation of projects were eventually built, the price of PV had plummeted, and no new CSP projects were built in the U.S. after that.” said Hank Price, the new firm’s Chief Operating Officer.
These first and second generations of CSP were built when renewable energy requirements barely reached 10%, and utilities at the time simply sought the cheapest renewable energy to meet initial targets. Storage was only seen as adding value if it could be shown to reduce the overall cost of energy, so few projects incorporated storage, and those that did were generally designed with little flexibility in how the storage could be operated.
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With solar photovoltaics now widely accepted as the lowest-cost form of electricity that mankind has ever created, utilities have rightfully deployed these resources in increasing amounts. CSP is inherently more expensive per unit of energy, and there is no sense attempting to compete at the times of day when PV can deliver electricity directly for a few cents per kilowatt-hour. But CSP has a role to play in delivering electricity at times when PV resources, even with batteries, are less suitable for the need.
Batteries are currently being widely adopted for short-duration energy storage for 4 hours or less. However, many studies have shown that the closer we get to full decarbonization, the greater the need to add long-duration energy storage.
Due to the very low cost of PV now, batteries combined with PV can be as low as 8 to 10 cents/kWh when discharged just for a few hours. However, battery cost can lead to a combined price of as much as 15 cents per kWh for longer durations.
“As utilities start to add significant amounts of batteries, they’re realizing that batteries alone may not be enough,” said Price. “And so it opens a door for CSP+TES that can provide this longer duration of energy storage and other attributes that they value, more similar to gas plants.”
Supplying this need is what drives the newly formed firm.
SolStor Energy to generate solar at night, by focusing on developing concentrating solar power configurations designed to complement PV by primarily delivering electricity after-dark from thermal energy storage CSP+TES
Along with Morse, Price was involved in developing the 250 MW Solana CSP project with six hours thermal energy storage for Arizona Public Service and the 250 MW Mojave CSP project for PG&E. At his firm, Solar Dynamics, Price has demonstrated the feasibility of running concentrating solar power to deliver energy to meet the evening peaks like a gas peaker plant.
SolStor is now looking to develop the third generation of CSP plants in the U.S and the motivation is driven by its ability to incorporate long-duration energy storage. “We are already submitting bids to RFPs in the Southwest, so several utilities know we exist,” said Lara, SolStor’s Chief Technical Officer.
“California has set a goal to achieve 100% carbon-free power generation by 2045. If you’re really going to get to 100%, you need to be able to produce power whenever it is needed. That’s where the opportunity for CSP comes in, where the renewable resource in California is primarily solar. So there’s an opportunity for CSP plants that are primarily serving nighttime generation by collecting energy during the day and producing power at night.” California alone will need 43 GW of energy storage by 2050, according to a study by the grid operator CAISO. 100% renewable targets change the landscape.
While the early renewable targets that facilitated the deployment of the first big CSP projects ranged from 10% to 20%, legislation now looks to the end goal of phasing out fossil fuels entirely. Nevada requires 50% in six years and 100% by 2050. New Mexico requires 80% by 2040. Arizona Public Service has a 100% target by 2050.
“Now the policies have lined up to make CSP feasible again. There is a growing need for the very kind of energy a CSP plant can provide when that energy is needed” said Morse.
“Last year, the California Public Utility Commission set aside one gigawatt for long-duration storage, anything that could operate for more than eight hours, which CSP + TES can do, and another gigawatt was set aside for firm dispatchable power, where CSP could also compete.”
The firm plans to leverage new opportunities uncovered by the Inflation Reduction Act (IRA), which has been hailed as the most ambitious climate bill ever passed in the US, partly by extending and improving the ITC.
Another change in California since the Obama era CSP is a new kind of off-taker. New big solar projects might not only depend on contracts with the three large investor owned utilities or the municipal utilities.
“California has this new type of utility: Community Choice Aggregators (CCAs). These are almost like new municipal utilities that are starting to buy power,” said Price.
“And they are starting to focus on this 2045 goal: how to decarbonize the power sector. These CCAs are driven by users who are very much focused on reducing fossil fuels in power generation. So, there’s a lot of interest in technologies that can replace natural gas and provide reliability for power generation. CSP offers a very interesting option as synchronous generation and the ability to back it up to have complete reliability for extended cloudy periods.”
