The author is a Reuters Breakingviews columnist. The opinions expressed are his own.

By Edward Chancellor

LONDON, June 26 (Reuters Breakingviews) - To paraphrase Mark Twain, speculative bubbles don’t repeat themselves, but they often rhyme. The green technology boom that has imploded over the past three years is remarkably similar to the alternative energy bubble that inflated prior to the global financial crisis of 2008. Both frenzies were driven by investors’ unrealistic expectations about how quickly new energy technologies would be taken up.

What is now known as the Cleantech 1.0 boom took off in 2005 after the U.S. Congress enacted tax credits for renewable energy. Former Vice President Al Gore’s 2006 documentary “An Inconvenient Truth” raised public awareness of climate change. In early 2007 the venture capital investor John Doerr gave a much-publicised TED talk in which he asserted that “green technologies – going green – is bigger than the internet. It could be the biggest opportunity of the twenty-first century.” Doerr’s firm, Kleiner Perkins, later launched a fund to “help speed mass market adoption of solutions to the climate crisis.” Many other venture capitalists jumped on the bandwagon.

The WilderHill Clean Energy Index, launched in 2004, more than doubled between May 2005 and December 2007. Dozens of startups were launched to invest in batteries, solar, biomass and wind energy. An electric vehicle company, Better Place, established in Silicon Valley in 2007, raised nearly $1 billion to build a network of charging stations. Solyndra, an innovative solar panel manufacturer, attracted a host of big-name investors and later received more than $500 million in loan guarantees from the administration of President Barack Obama.

No single factor was responsible for pricking the bubble. The collapse of Lehman Brothers in September 2008 dampened animal spirits; advances in hydraulic fracturing technology led to cheaper U.S. natural gas; Spain and Germany reduced their subsidies for renewable energy; and American solar companies proved unable to compete with subsidised Chinese competitors. Nearly all the 150 renewable energy startups founded in Silicon Valley during the boom subsequently failed, including Solyndra and Better Place. Cleantech venture capital funds launched during the bubble produced negative returns. By the end of 2012 the WilderHill index had fallen 85% from its peak to around 40. By coincidence, that is where the benchmark currently trades.

The recent green tech bubble was more extreme. The WilderHill index climbed from 47 in March 2020 to 281 less than a year later. Whereas U.S. venture capitalists spent an estimated $25 billion funding clean energy startups between 2006 and 2011, Silicon Valley splurged more than twice that sum in 2021 alone, according to Silicon Valley Bank. Market valuations were quite absurd. By late 2020, the battery company QuantumScape QS.N, which came to the market by merging with a blank-check firm, was valued at more than General Motors GM.N, despite having no sales.

The market frenzy is long past. QuantumScape stock is down more than 95% from its peak, while the WilderHill index has fallen 85%. Several listed electric vehicle companies, including truck maker Nikola, have filed for protection from creditors. President Donald Trump’s administration is reducing subsidies for renewables and electric vehicles. Oil giants BP BP.L and Shell SHEL.L are cutting back their alternative energy investments, just as they did after the Cleantech 1.0 boom. The outcome for green venture capital remains unclear but anecdotal evidence suggests that many funds are now changing hands at steep discounts to their appraised valuations.

The common error investors made during both booms was to become entranced by extravagant growth forecasts. In his book, “More and More and More: An All-Consuming History of Energy”, Jean-Baptiste Fressoz criticises the application of the sigmoid function – also known as the S-curve – to predict the course of the energy transition.

This model describes the adoption of a new technology as starting out slowly, rapidly gathering pace before eventually levelling off when the market becomes saturated. The United Nations Intergovernmental Panel on Climate Change has used the S-curve in its projections for renewable energy demand and the accompanying decline of fossil fuels.

The S-curve was originally discovered a hundred years ago to describe how the population of drosophila flies changes under laboratory conditions. It was later applied, with varying degrees of success, to project human population growth. The American energy scientist M. King Hubbert was the first to use the S-curve to forecast energy production. In the 1950s, advocates for nuclear energy used the model to predict what they believed was the inevitable transition from fossil fuels towards an atomic-powered future. Hubbert also used the S-curve for his famous forecast that U.S. oil production would peak in 1970.

Vaclav Smil, a leading energy historian, points out that energy transitions are slow, inherently unpredictable and require extraordinary amounts of investment. Fressoz goes further, claiming that – when energy consumption is viewed in absolute rather than relative terms – there has historically never been a transition. It’s true that coal took over from wood as the world’s prime energy source in the 19th century, and that later oil and natural gas became dominant. Yet the consumption of all these energy sources continued increasing. The world has never burned more wood than it does today. In absolute terms, coal usage continues to grow.

The S-curve has also been used to predict the uptake of various green technologies. As Rob West of Thunder Said Energy, a research firm, observed in a report published last September, both the speed of adoption and the ultimate penetration rate for new inventions are variable. For instance, the demand for refrigerators and television by U.S. households grew very rapidly from the outset, with both reaching penetration rates of nearly 100% in just a few decades. Yet it took more than half a century for gas heating to reach 60% of U.S. households, at which point its market share flatlined.

“It is important not to fall into the trap of assuming that the ‘top of the S’ is an endpoint of 100% adoption,” writes West. Not long ago, electric vehicles were set to rapidly replace the internal combustion engine, but sales forecasts are now being cut back in developed markets. West anticipates that the eventual market share for battery-powered cars will not surpass 30%. That’s a guess. The actual outcome will depend on the state of future technology, which is unknowable. That leaves plenty of scope for green investors to get it wrong again.

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(Editing by Peter Thal Larsen; Production by Oliver Taslic)

((For previous columns by the author, Reuters customers can click on CHANCELLO/edward.chancellor.bv@gmail.com))