CSP experts launch SolStor Energy: long-term storage for the US

A team of industry experts have joined forces to form SolStor Energy, a new US development company dedicated to deploying concentrated solar power (CSP) with thermal energy storage (TES) to deliver solar energy at night. SolStor is focused on developing concentrated solar power configurations designed to complement photovoltaics, primarily by providing electricity after dark from thermal energy storage.

Three SolStor Energy team members were separately recognized with the SolarPACES Lifetime Achievement Award for their CSP achievements – Fred Morse (2013), David Kearney (2018) and Xavier Lara (2022).

“We see some large and growing markets for night-time energy, so the demand is there. There are state and federal incentives that make it easier to complete projects. Because we know what is needed and we know how to build CSP plants, we decided to start a CSP development company,” said Morse, a long-time CSP expert at DOE, Morse Associates at Abengoa, and now founder and CEO of SolStor Energy.

First two generations of CSP in the US

The operations of earlier generations of CSPs in the US resulted from different market conditions. The first generation, developed in the 1980s and 1990s, was strongly influenced by the oil embargo of the 1970s and the country’s ambitions for energy diversity and energy independence from external energy sources. At that time, electricity from CSP was cheaper than from photovoltaics. So the first projects in Kramer Junction and Daggett, California were CSP,” explained David Kearney.

The second generation of CSP plants, operating in 2000 and 2010, were derived from the state’s Renewable Portfolio Standards (RPS), which required a relatively small percentage of energy to come from renewable energy sources. “By the time the next generation of projects were finally built, the price of solar PV had plummeted, and no more new CSP projects were being built in the U.S. since then.” said Hank Price, the new company’s chief operating officer.

The first and second generation CSPs were built when renewable energy demand was barely reaching 10% and utilities at the time were simply looking for the cheapest renewable energy to meet their initial goals. Storage was only seen as adding value if it could be shown to reduce overall energy costs, so few projects incorporated storage, and those that did were generally designed with little flexibility in how to operate storage.

SolStor is moving from competing to complementing…

With photovoltaics now widely recognized as the cheapest form of electricity ever produced by humanity, utilities are rightly using these resources in increasing amounts. CSP is inherently more expensive per unit of energy, and there is no point in trying to compete during those times of day when solar PV can directly provide electricity for a few cents per kilowatt hour. However, CSP has a role to play in providing electricity during periods when solar resources, even in the case of batteries, are less adequate to meet needs.

…because long-term storage is crucial in a 100% renewable grid

Batteries are now widely used for short-term energy storage of 4 hours or less. However, many studies have shown that the closer we get to full decarbonization, the greater the need to add long-term energy storage.

Due to the currently very low cost of photovoltaics, battery costs combined with photovoltaics can be as low as 8-10 cents/kWh when discharging for only a few hours. However, the cost of batteries can result in a total price of as much as 15 cents per kWh over longer periods of use.

“As utilities start adding significant amounts of batteries, they are realizing that batteries alone may not be enough,” Price said. “This opens the door for CSP+TES, which can provide longer energy storage times and other attributes they value, more similar to gas plants.”

Satisfying this need is the driving force behind the newly established company.

With Morse, Price was involved in the development of the 250-MW Solana CSP project with six-hour thermal energy storage for Arizona Public Service and the 250-MW Mojave CSP project for PG&E. With his company Solar Dynamics, Price has demonstrated the feasibility of using concentrated solar power to provide power to cover evening peaks, much like a gas-powered peaker plant.

SolStor is currently planning the development of third-generation CSP plants in the US, and is motivated by the opportunity to incorporate long-term energy storage. “We are already bidding on tenders in the Southwest, so several utilities are aware of our existence,” said SolStor CTO Lara.

“California has set a goal of achieving 100% carbon-free energy generation by 2045. If you really want to get to 100%, you need to be able to produce energy when you need it. This is where the opportunity for CSP comes in, with the renewable energy source in California being primarily solar. There is therefore an opportunity for CSP plants, which are mainly used to generate energy at night, storing energy during the day and generating it at night. A study by grid operator CAISO shows that by 2050, California alone will need 43 GW of energy storage. 100% renewable goals are changing the landscape.

While the initial renewable energy targets that facilitated the first major CSP projects ranged from 10% to 20%, the legislation now focuses on the ultimate goal of completely phasing out fossil fuels. Nevada needs 50% in six years and 100% by 2050. New Mexico needs 80% by 2040. Arizona Public Service has a goal of 100% by 2050.

“Now the policies have been adjusted to make CSP feasible again. “There is a growing demand for the type of energy that a CSP plant can provide when it is needed,” Morse said.

“Last year, the California Public Utilities Commission allocated one gigawatt for long-term storage, which is anything that can run longer than eight hours, which CSP + TES can do, and another gigawatt was allocated for permanent dispatchable power, where CSP could also compete.”

The company plans to capitalize on new opportunities uncovered by the Inflation Reduction Act (IRA), which has been hailed as the most ambitious climate bill ever passed in the U.S., in part by expanding and improving the ITC.

New customers are serious about replacing their gas

Another change in California since Obama’s CSP is a new type of recipient. New large-scale solar projects may depend on more than just contracts with the three large investor-owned utilities or municipal companies.

“California has a new type of tool: community choice aggregators (CCAs). “It’s almost like new utilities starting to buy energy,” Price said.

“They are starting to focus on the 2045 goal: decarbonizing the energy sector. These CCAs are operated by users who are very focused on reducing the use of fossil fuels in energy generation. Therefore, there is great interest in technologies that can replace natural gas and ensure reliable energy production. CSP offers a very interesting option such as synchronous generation and backup capabilities to ensure full reliability during extended periods of cloud cover.

Developers and utilities Mull Solar Storage for 100% clean energy in the South West

What happened to Crescent Dunes?

Will the US manage to implement long-term energy storage?