Ty Daul, CEO of Primergy, discusses how the Quinbrook-launched developer brought online the US’s largest co-located solar-plus-storage power plant.
Gemini, a 690MWac/966MWdc solar PV plant paired with a 380MW/1,400MWh DC-coupled battery energy storage system (BESS), sits just off the Valley of Fire highway through Clark County, Nevada.
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Even in a region of the US desert northwest peppered with highly visible large-scale solar power plants that make any flight over the area a little bit less of a chore for renewable energy enthusiasts, it stands out for its evident scale.
The project went into commercial operation in March last year but as CEO Ty Daul explains, Primergy and its backer Quinbrook Infrastructure Partners held off from making the official announcement until July.
That’s a customary move in the energy industry, as developers and investors take some time to sign off approvals and ensure everything works before the grand unveiling.
As Daul explains, the development, design, integration, and construction of the project were very complex, as were aspects of the financing and offtake structure.
“If you look at Gemini, it’s about 6,000 acres. The complexity around the project, the offtake, the permitting, and then the financing was a bit daunting at first.”
The site is administered by the Bureau of Land Management (BLM), the US government body responsible for federal land and that made permitting somewhat more complicated than for projects on private land.
Then, the offtake deal, which is a 25-year power purchase agreement (PPA) to supply utility NV Energy with renewable energy even through evening peaks, has what Daul claims a “unique” structure.
“The PPA itself, there’s a base rate, and then there’s a ‘peak rate.’ During the summer months, during certain hours, there’s a kind of multiplier on the PPA rate.”
Finally, being a DC-coupled solar-plus-storage hybrid resource project on a scale rarely seen before meant that integration was, if not tricky, then something the company and its partners had to be absolutely sure of getting right.
“We spent probably a year and a half just focusing on making sure we had all of the integration right, [that] we understood the operations, working through very detailed design, way before we started even procuring the equipment for the project,” Ty Daul says.
“Making sure that the systems were responding as required and balancing throughout the site. Being DC-coupled, we don’t have a big single location where all the batteries are; there are 181 power blocks that have batteries throughout the site. Making sure that the entire system works well together, the DC-coupling and that interaction on the control system and everything.”
In 2023, Primergy signed a deal with Gemini’s BESS supplier, CATL, for 10GWh of systems to be deployed over the next five years. IHI Terrasun served as Gemini’s battery storage system integrator.
Gemini offtake structure ‘solves an energy problem’ for NV Energy
Meanwhile, financing Gemini presented three areas of what Daul says may be unprecedented complexity in the industry.
It was the “largest project ever brought forward,” the largest project to secure tax equity financing—around US$500 million in total—and featured the “unique” PPA structure with NV Energy.
“Typically [with solar-plus-storage co-location], what you see is a PPA on the PV side of it, and then a tolling agreement on the battery side of it, which a lot of projects are doing, we’ve got some that are like that as well,” Daul says.
“So, it [Gemini’s offtake] was a very unique structure.”
The business model that enabled the peak time-shift PPA was a result of the developer “trying to solve an energy solution for the customer,” the CEO says.
“If you look at the way Gemini operates, NV Energy basically wants to do a time shift. They’ve got peak load in the afternoons in Las Vegas, and it carries on well into the evening. So, they wanted to be able to shift that solar power into the later hours, and that was one of the primary focuses on the structuring around that offtake.”
Primergy also sold 49% equity in the Gemini project to Danish pension fund APG, which Daul says was about optimising the developer’s capital, while a recent US$125 million tax equity sale of the project to Rabobank helped it in a recent US$225 million raise for the Valley of Fire portfolio of projects it has in operation, development and construction.
Valley of Fire projects
Primergy, launched by Quinbrook in 2020, has raised close to a billion dollars in financing since April last year for its Valley of Fire portfolio, which totals 2.5GW of solar PV and 1.5GW/6GWh of battery storage.
The Valley of Fire projects are situated in the trio of states that surround the Clark County State Park of the same name: Nevada, Arizona and Colorado. It includes Gemini, as well as Purple Sage Energy Center, also in Nevada but with California Community Choice Aggregator (CCA) San Diego Community Power as its main offtaker.
Purple Sage, currently in development, will comprise 400MWac of solar with an even bigger BESS installation than Gemini’s, at 400MW/1,600MWh. It will also have a bigger tax equity investment than its predecessor.
As we heard in our news story earlier this week, Primergy sees projects of this scale as a trend rather than an anomaly for the renewable energy industry, whether with a single offtaker as with Purple Sage and Gemini, or more likely with multiple contracts.
Daul says that even where the company develops solar-only projects in its build-own-operate independent power producer (IPP) business model, it models the design and grid interconnection with the later addition or co-location of battery storage in mind.
Some ‘chop in the waters’ ahead with Trump, but solar and BESS still a winning combination
Finally, looking ahead to the incoming Republican presidential administration led by Donald Trump, Daul says that having been in the energy industry for more than 30 years and through many administrations, he is “optimistic long-term” but admits there may be “some chop in the waters, probably for the next six months to a year.”
“There might be some changes to the Inflation Reduction Act (IRA), and likely some changes to some of the trade and policy issues around clean energy. I think overall, it’s not a real big impact to the overall industry, to the market,” he says.
“At the end of the day, we’ve succeeded as an industry, and a large part of that is because of the technology improvements, the use cases and the acceptance from customers.”
The fact that solar and battery storage are among the quickest and easiest energy technologies to deploy, means that where there is rising electricity demand—and there is a lot of rising electricity demand in the US—these technologies “are still going to be very, very good solutions to the market’s energy needs,” Daul says.
