Jun 3, 2026 · 39m · green-blueprint
The perovskite bet that could transform solar
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gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
In this episode of The Green Blueprint, host Lara Pierpoint interviews Tandem PV's Saritha Paruri about commercializing high-efficiency perovskite-silicon tandem solar panels, overcoming historical durability challenges, and using capital-efficient manufacturing to disrupt the utility-scale energy market.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. The hosts hold 31.6% of the talking time here. How this is scored →
The hosts as informed peer 4.3 Guest teaching 3.9 Guest disagreement 0.1 The hosts pushing back 0.2
speaking balance: gold is the hosts, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 29:05 Refuting investor accusations over equipment financing
Paruri displays her strongest combative tone when recounting how an investor accused her of lying about securing 100 percent equipment financing, sharply offering to show the term sheets.
Hardest push from the hosts ▶ 18:02 Probing bankability vs lab-only accelerated testingPierpoint constructively challenges the premise that accelerated testing alone is enough to check the box for risk-averse financial institutions without multi-decade track records.
Biggest teaching moment ▶ 7:28 Detailed efficiency roadmap and tandem stacking mechanicsParuri delivers a thorough breakdown of silicon and cadmium telluride efficiency ceilings, illustrating how multi-junction perovskite layering unlocks pathways beyond 45 percent.
The host holds their own ▶ 9:27 Applying Solyndra historical lessons to silicon compatibilityPierpoint demonstrates deep industry knowledge by citing the Solyndra collapse to emphasize that leveraging existing silicon manufacturing infrastructure is critical for commercial success.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | The hosts as informed peer | Guest teaching | Guest disagreement | The hosts pushing back | Why |
|---|---|---|---|---|---|---|
| Perovskite Solar Fundamentals Versus Conventional Silicon Photovoltaics | 5 | 4 | 0 | 0 | Pierpoint establishes full transparency as a two-time investor in Tandem PV and frames the discussion around perovskite advantages. Paruri details the thin-film material physics and supply chain benefits over silicon in a cooperative dynamic. | |
| Efficiency Limits of Silicon and the Multi-Junction Tandem Roadmap | 6 | 5 | 0 | 0 | Paruri outlines theoretical efficiency ceilings across silicon, CdTe, and perovskite tandems. Pierpoint displays domain expertise by linking manufacturability to historical lessons learned from Solyndra's bankruptcy. | |
| Tandem PV Origin Story and Executive Team Formation | 3 | 3 | 0 | 0 | Paruri shares Tandem PV's origin story out of Stanford and her personal timeline from company advisor to full-time executive. The atmosphere is warm, conversational, and aligned. | |
| Prioritizing Utility-Scale Developers over Distributed Solar Markets | 4 | 5 | 0 | 0 | Paruri explains the strategic counterintuitive decision to pursue utility-scale solar over rooftop markets due to balance-of-system cost compression and land constraints. Pierpoint validates the rationale. | |
| Overcoming Perovskite Degradation and Industry Adoption Playbooks | 5 | 5 | 0 | 2 | Pierpoint presses on whether accelerated laboratory aging truly satisfies conservative project financiers without decades of outdoor data. Paruri clarifies the phased deployment playbook where developers commit 5 to 10 percent of projects first. | |
| Constructing the Demonstration Line and Securing Paid Customer Pilots | 4 | 4 | 0 | 0 | Paruri describes adopting First Solar's MVP roadmap by piloting quarter-size panels with 12 utilities and IPPs to reduce capital expenditure and speed up deployment. The conversation is collaborative and informative. | |
| Hybrid Manufacturing Strategy and Protecting Core Intellectual Property | 5 | 4 | 1 | 0 | Paruri discusses securing 100 percent equipment debt financing due to off-the-shelf tooling and strong cap table backing, sharing an anecdote confronting a skeptical investor. Pierpoint enthusiastically concurs. | |
| Operational Execution, Factory Build-out, and Budget Discipline | 3 | 3 | 0 | 0 | Paruri highlights operational discipline and rapid real estate acquisition, finishing the demonstration facility within 7,000 dollars of budget. Pierpoint offers supportive commentary. | |
| Navigating Federal Policies, Domestic Manufacturing Tariffs, and ITC Dynamics | 6 | 5 | 0 | 0 | Pierpoint cites insights from the Department of Commerce regarding import supply chain bottlenecks. Paruri explains how Section 45X and domestic content bonuses create strong market demand, positioning high-efficiency panels as a hedge against ITC expiration. | |
| The Hundred-Million-Dollar Vision for Giga-Scale Solar Manufacturing | 2 | 1 | 0 | 0 | Pierpoint asks a closing hypothetical question regarding deploying 100 million dollars into gigascale manufacturing, ending on an encouraging note. |
Statements from this episode (22)
Paruri: Tandem PV expects to reach 35% to 36% solar efficiency in medium term
“Our team believes that we'll be at 35, 36% efficiency in the medium term and there's so much more room to grow.”
Paruri: Perovskite Solar Uses One-Tenth the Energy of Silicon per Watt
“We use one-tenth the amount of energy required to make on a watt per watt basis compared to silicon.”
Paruri: Perovskite Solar Requires No Rare Earths and Nothing From China
“There's no rare earths or critical minerals, no kind of Supply chain sensitivities or vulnerabilities, right? Like nothing from the inputs or the tools has to come from China.”
Paruri: Most past perovskite solar companies have been a joke
“Every perovskite company I've looked at has just not been compelling, and I think they're kind of a joke.”
Paruri: US silicon solar panels will max out at 25% efficiency
“So your average silicon panel here in the U.S. Is 23% efficient. It'll probably get to 25% in the next couple years, and that's it. Like, that's the max that a silicon solar panel will go.”
Paruri: Tandem PV has achieved over 30% panel efficiency
“Take that into the context of a recent announcement that we just made, which is that we've now crossed 30% efficiency On a solar panel, right?”
Paruri: Perovskite-silicon tandems can reach 45% efficiency
“But this technology of perovskite and silicon can get up to 45% efficiency.”
Paruri: All-perovskite tandems could achieve 60% to 70% efficiency
“And over time, you can engineer out the silicon, and you're just doing perovskite on perovskite on perovskite tandems, You can get to 60 or 70% efficiency.”
Paruri: Utility-scale solar accounts for 80% of the solar market
“Utility scale solar is 80% of the market, right?”
Paruri: Tandem PV delivers 30% efficiency boost over silicon, 50% over CdTe
“When you think about our technology compared to silicon, it's like a 30% improvement. When you think about it in compared to cad tell, it's a 50% improvement.”
Paruri: Tandem PV's market beachhead is utility-scale solar
“Utility scale is where we're going. That's the beachhead, and probably where we may just stay.”
Paruri: Tandem PV Tested Module Outdoors for 18 Months Without Degradation
“For the last few years, we've been making 10,000 panels a year, testing those in our indoor accelerated labs and also external testing And, you know, we're there on our kind of R&D format where we're able to, you know, we had a module outdoors for 18 months wi…”
Paruri: Tandem PV fully commissioned its demonstration factory in January 2026
“We placed deposits on equipment at the end of 24, early 25. We got the equipment, started getting it in September of 25, and the factory is fully commissioned in January of this year.”
Paruri: Tandem PV to launch paid pilots with nearly a dozen U.S. utilities and IPPs
“In the next couple months we're gonna be kicking off paid pilots with almost a dozen customers here in the U.S. Between utilities and IPPs.”
Paruri: Tandem PV's factory uses off-the-shelf thin-film equipment
“So if you look at our factory, it's all, you know, off the shelf thin film equipment.”
Paruri: Tandem PV secured 100% equipment financing for demonstration factory
“My understanding is that it's pretty unheard of, but we were able to get a hundred percent equipment financing for this demonstration factory. And so between that and venture debt, we were able to finance this 40 megawatt nameplate factory which is great.”
Paruri: Taking over EnerVenue site saved Tandem PV months and millions
“Taking over the EnerVenue building made kind of our build-out months shorter, millions of dollars cheaper,”
Paruri: Tandem PV factory build-out was over budget by only $7,000
“Once we kind of had the updated budget after we identified the building, we turned up this whole factory and we were over budget by literally 7000 dollars. Multi-million dollar build out, and we're 7000 dollars over.”
Paruri: Tandem PV avoided solar tariffs using semiconductor equipment exemptions
“Ultimately we saw that we actually can get our equipment through an exemption because we were, it was semiconductor equipment, so that was great.”
Paruri: Tandem PV customers safe-harbored ITC pipeline through mid-2030
“All of our customers utility-scale customers were able to successfully safe harbor, like, gigawatts worth of project pipeline, and so the investment tax credit for all of our customers is still intact through mid- twenty-thirty.”