Using solar energy in the dark is closer than you think


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In May, when Tesla Motors announced its new battery product to vast media buzz, the talk was all about people putting batteries in their solar-powered homes, and thereby becoming that much less reliant on the grid.

But there was always another and perhaps even bigger side of the story — the idea that very large scale batteries or battery packs could help out the grid itself by storing large amounts of solar energy for use in the evening or at night. The ultimate effect might be to displace electricity generated from coal or natural gas, and convert an inherently “intermittent” renewable energy source — solar — into a more constant one.

So is it happening? The answer seems to be yes — 2015 has seen several key announced, completed, or experimental grid-scale projects pairing batteries and solar photovoltaic panels….

Indeed, SolarCity — which is chaired by Tesla CEO Elon Musk — has just announced plans to bring precisely this combo to Hawaii, a state that continues to lead the way when it comes to the adoption of solar and batteries, thanks to its towering electricity costs, which are the highest in the nation.

SolarCity and the Kauaʻi Island Utility Cooperative jointly announced last week that they’ve entered into a solar power purchase agreement in which SolarCity will provide 20 years of power from a 52-megawatt-hour battery installation that will be able to send as many as 13 megawatts of electricity to the island’s grid. The battery will draw power from an accompanying solar array.

The biggest news is when the energy would be supplied: the evening. “What makes this exciting is basically that it’s dispatchable solar that will be available at night,” says Peter Rive, the chief technology officer of SolarCity. The system is slated to be running by the end of 2016, said Rive, and will likely use Tesla batteries for the energy storage component.

Once that happens, solar energy will be no longer confined to simply being used when the sun is shining, at least on Kaua’i. Rather, thanks to storage, its use will be shifted to other hours of the day — removing one reason that power plants have often been powered by various types of fossil fuels (on Kaua’i, diesel), which of course can burn at any hour…

There are other examples, similar approaches – not quite the same. To me that is extraneous. What counts is that folks are working at one more avenue to make solar power generation practical.

Walking one small step at a time towards freedom from fossil fuel.

6 thoughts on “Using solar energy in the dark is closer than you think

  1. drugsandotherthings says:

    hmm, interesting- not the least of which is because it’s Kauai. When I lived there in the first decade of 2000, it was not even a net metering state (in other words- the utility paid you pennies on the $ for the excess power you put into the grid). The power was, pretty much, all diesel generation.
    And the county (Kauia is a county of the state of Hawaii) hired an independent auditor to come look at the islands- whose conclusion, unsuprisingly, was that they could be energy independent. Solar. Wind. Ocean wave energy. Geo-thermal. At which point the (sadly, I forget which) gas company that supplied the island essentially said “if your use of diesel drops below current levels we will hike the price tremendously”.

    Well, I have no doubt many of the billionaires that live there are fans of Musk. And when I was there- even many of the very conservative ones were incensed with the solar/diesel situation…

  2. Dollars & sense says:

    “Energy storage will disrupt transmission and distribution investments : Energy storage systems that allow for the deferral of T&D upgrades allow for a more efficient deployment of capital to meet evolving grid needs and can enable the development of new business models.” (Utility Dive 10/17/17) http://www.utilitydive.com/news/energy-storage-will-disrupt-transmission-and-distribution-investments/506945/ “Grid operators around the world continue to recognize the benefits of energy storage technologies, and one of the most intriguing applications is the ability to defer investments in conventional transmission and distribution (T&D) infrastructure.
    Energy storage systems (ESSs) providing T&D upgrade deferral can be a disruptive force in the industry as they allow for a more efficient deployment of capital to meet evolving grid needs and can enable the development of new business models. T&D upgrade deferral ensures that electricity lines, substations and other equipment have enough bandwidth to handle peak demand. Navigant Research’s recent report, Energy Storage for Transmission and Distribution Upgrade Deferral, takes an in-depth look at both the opportunities and challenges in this market.”

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