Solving the Solar Power Storage Problem

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One of the big questions about solar power is how to supply sun-driven electricity at times of peak demand. Demand spikes in the early morning, before the sun is high enough to hit solar panels, and in the early evening, when solar panels operate at only at half efficiency in the low light. Cost-effective storage has been a major issue to be solved.

Electric batteries have been used, but they’re expensive and have a limited lifetime, so they are usually online to even out a plant’s production, not to store large amounts of solar energy overnight.

Now, Solana, a $2 billion solar project near Phoenix, is pioneering a new method of solar storage. A network of mirrors focuses sunlight onto black-painted pipes, which carry heat to tanks of molten salt. At night, the plant draws heat out of the molten salt to continue making steam and electricity. Solana gathers heat almost twice as fast as its steam turbines can use it, so on a sunny day, the plant turns out power steadily.

Its production can be throttled back at hours when photovoltaic cells are producing current, or at night, when demand is low. Arizona Public Service buys 100 percent of Solana’s power and decides when to use it. Another project in California, Ivanpah, has developed a similar means of solar storage. It uses a field of mirrors mounted on pillars to focus sunlight on a black tower, which reaches very high temperatures and from which heat can be drawn.

These solutions to solar power storage are so promising that last week the California Public Utilities Commission approved a rule that requires the state’s three big investor-owned utilities to install solar storage by 2024. That’s real progress toward renewable energy as the power of the future.

Article by John Howell, appearing courtesy 3BL Media.

About Author

Walter’s contributions to CleanTechies over the past 4 years have been instrumental in growing the publications social media channels via his ongoing editorial and data driven strategies. He is the founder and managing director of Sunflower Tax, a renewable energy tax and finance consultancy based in San Diego, California. Active in the San Diego clean technology community, participating in events sponsored by CleanTech San Diego, EcoTopics, and Cleantech Open San Diego, Walter has also been a presenter at numerous California Center for Sustainability (CCSE) programs. He currently serves as an adjunct professor at the University of San Diego School of Law where he teaches a course on energy taxation and policy.

2 Comments

  1. douglas prince on

    Odd article. First, demand is highest in the middle of the day, not in early morning or early evening. Everyone knows that. And molten salt storage is nothing new. Again, pretty well known by everyone.

    So what was the point of printing this blurb?

  2. Hi,

    It is really good news for the residents (who are willing to use Solar Power :) ) of North America. If it is worked, ok. Otherwise, there is another option for North American people to use SMA inverter.

    Here in Australia, the SMA Solar Technology inverter is used to store energy which is sufficient for a four-person family about three hours of power.

    Best of luck for future.

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