Solar plus storage beats out “cheap” gas to serve evening peaks

US solar manufacturer and developer First Solar is to build a 65MW solar farm and a 50MW/135MWh battery storage facility in Arizona – after beating out peaking gas plants to provide power into the evening peak.

The win by First Solar – in its first big foray into solar plus storage – confirms the swing point in “dispatchable power” is rapidly moving away from fossil fuel generators to wind and solar technologies paired with storage.

The facility will take advantage of Arizona’s excellent solar resources to deliver power – either directly from its solar facility or via its solar-fuelled battery – between 3pm and 8pm, hitting the local peaks on the grid in summer.

The local utility, Arizona Public Service (APS),  called for proposals from any technology to deliver the power in the afternoon and evening peak.

And despite the prevalence of so-called “cheap” gas in the US, the solar plus storage facility won out over proposals from conventional renewables, standalone batteries and natural-gas peaking plants.

Greentech Media said the joint system “suggests a new paradigm for solar-rich markets: the solar peak power plant.”

It said the solar plant will charge up the battery during the day and deliver power during the first few hours of the peak window, until the sun sets. Then the battery will kick in and discharge stored power through the rest of the window.

It says the wind for First Solar marks yet another phase in solar and storage’s cost advantage over fossil fuels.

Another Arizona utility, in Tucson, recently announced a bid of just $US45/MWh for a solar and storage facility (100MW solar and 30MW/three hours of storage), while Xcel Energy’s recent EOI elicited bids for wind and solar and storage of between $US21/MWh and $US36/MWh.

Greentech Media noted that the new Arizona projects marks several notable milestones.

It is First Solar’s first publicly announced storage project, and the company is expecting more. Spokesman Steve Krum told Greenwich Media that such models would become “very common in many of our markets”.

It is also good for Arizona’s own plans, championed by  Arizona Corporation Commission Andy Tobin, to pursue a clean energy share of 80 per cent by leveraging storage for clean peak power.

That plan would require an impressive 3GW energy storage to be installed by 2030, meaning it would overtake California and New York for the biggest storage mandate in the country.

Thirdly, the project showcases an even ratio of solar to storage capacity, Greenwich media noted.

The groundbreaking Tucson Electric Power hybrid PPA got to $45 per megawatt-hour with 100MW of solar and 30MW of 4-hour storage.

“The new APS project has stepped a bit closer to 1-to-1. That reflects cheaper battery costs making larger systems tenable, but it also means the value proposition is changing. Storage is no longer a nice add-on to a solar project; it played the key role in winning this bid.”

First Solar CEO Mark Widmar said the project marked the next step in solar energy because it allows the power of the sun to be used in the evening when the energy is needed most.

“Through this innovative project we are excited to partner with APS to demonstrate the capabilities of solar coupled with large-scale battery storage. Together, these technologies highlight the significant role for solar in providing reliable, First cost-effective energy.”