A solar expert shares her opinions, and isn’t afraid to change them

By Nathaniel Bullard

Today our columnist talks to Jenny Chase, a solar analyst known for sharing her blunt views on the clean energy sector. You can read and share this column on Bloomberg.com. For unlimited access to climate and energy news, please subscribe.

A solar expert shares her opinions, and isn’t afraid to change them

By Nathaniel Bullard

Every year since 2017, BloombergNEF solar analyst Jenny Chase has published on Twitter (now rebranded X) a list of her opinions about the sector she has covered for nearly two decades. Many people inside and outside the industry read it with interest — and delight — as a clear lens on solar energy’s present, an informed speculation on its future and a glimpse of other clean-energy trends to watch.

This year, Chase’s takes range from the sweeping — “Solar is the cheapest source of bulk electricity in many countries, and the quickest to deploy, and now you couldn’t stop it being built if you wanted to” — to the more practical: “Get your rooftop solar system built when you have scaffolding up for something else, ’cos scaffolding is expensive,” she writes. “Ideally build it when you’re building the roof, there will never be a better time. Rooftop solar mandates are good and should be more common.” 

Workers install solar panels at a home in San Francisco, Sept. 27, 2023.  Photographer: Michaela Vatcheva/Bloomberg

Now that she has six years’ worth of opinions behind her, I asked Jenny, who is my colleague, to reflect on how her thoughts have and haven’t changed as the solar sector itself has evolved. Which opinion does she hold most strongly?  Her answer comes from her original 2017 list, and has to do with power tariffs:

The problem Chase pointed to in her tweet is that solar can generate more power at midday than the grid needs, creating an imbalance between supply and demand. It’s still a problem in 2023, even as some markets, like California, are beginning so-called time-of-use tariffs that encourage production at certain hours and discourage it at others. 

Two of her other opinions, also from 2017, are close seconds, Chase said. The first of them will probably make solar developers wince:  “Many solar project developers complaining their problem is ‘finance’ are being disingenuous. Their problem is, their project is rubbish.” In other words, it’s not the market — it’s you. Secondly, Chase also still believes that, with a nod to Winston Churchill, “traded electricity wholesale markets are the worst way of dispatching energy resources, except for all the others that have been tried.” 

As for the opinion she has held the most loosely since 2017? It’s about batteries. Chase said six years ago that solar “is not a natural complement to household batteries. The grid exists for a reason, people, and big batteries are cheaper than small.” 

That no longer holds, she told me via email. The economics of residential battery installations “kinda work” today with subsidies, she said, but as can happen with consumer-driven choices, buying decisions often come before perfect economic conditions, not after.

That said, the grid still exists for a reason, “and we should be building more” of it in order to integrate solar and wind at ever-greater scale, she said. An expanded grid will also enable all the other decarbonization activities that will require much more renewable electricity.

Finally, I asked Jenny what has changed the most from last year’s list. She wrote: 

[Our team’s] 2030 build forecast increased from 460 gigawatts in 2030 (forecast as of October 2022) to 707 gigawatts in 2030, lol. Basically the team, especially in China, got the courage to start forecasting genuinely transformative amounts of solar. That’s the problem, when you ask a bunch of analysts to predict a transition, they cannot see something wildly different from what they have learned about.

The stepped-up projection relates to what I wrote in a recent column on US government economic data. In order to understand how a fast-moving present leads to a different future, we need a strong theory of how today changes, and why.

The history of the solar industry is a series of consecutive futures that, tested back, are wildly different from what came before. That is perhaps the most important opinion of Chase’s: Have the courage to make transformative forecasts, because the industry has a transformative habit. 

Nat Bullard is a senior contributor to BloombergNEF and writes the Sparklines column for Bloomberg Green. He advises early-stage climate technology companies and climate investors.