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Christopher Smith had his epiphany while hiking in Alaska. After seeing wagons of fossil fuels rattling along the railways, he wondered whether batteries charged by wind or solar farms could be shipped the same way. “I saw shipping containers with oil and coal and I thought we can use the rail network to move green energy. This was an ‘aha’ moment,” says Smith, then working as an engineer with the International Brotherhood of Electrical Workers.
Determined to turn his hunch into a business reality, Smith launched SunTrain in 2021 to explore how to ship giant containerised batteries to energy-poor parts of the US. A large battery mounted on a flatbed wagon in a railway siding at San Francisco port next to a small solar power installation shows how his vision is beginning to materialise.
Smith explains that his venture capital-backed start-up aims to run 120-wagon battery trains to deliver renewable energy using the existing US rail network. Although falling, coal shipments still accounted for 14 per cent of the 24.4mn carloads of US rail traffic last year, according to the Association of American Railroads. SunTrain calculates that one battery train could meet the daily energy needs of 120,000 homes. It is now signing transport contracts with utility companies and raising $30mn to scale its operations.
Like many countries, the US has long struggled to build enough high voltage transmission lines to meet demand: too many Nimbys and time-sapping planning permits make construction difficult. It took 17 years before the builders of the 550-mile SunZia transmission line in New Mexico broke ground last September. In a report last year, the US Department of Energy forecast that inter-regional transmission capacity would have to rise 114 per cent by 2035 to meet even a moderate rise in demand as supply switched to clean energy.
Alternatives have been dismissed. “Picture the windy plains of Iowa or the sunny deserts of Arizona. You can’t exactly ship sunlight in a railcar,” Bill Gates wrote last year. Only the mission-driven Smith thinks you can. ‘Trainsmission’, in his view, can provide a cheap, flexible and profitable response to the energy challenge that will help the planet and save railway workers’ jobs.
The idea behind SunTrain initially sounds crazy to many investors, admits Rob Carlson, managing director at Bioeconomy Capital, the company’s early stage funder. But it makes sense once you consider costs and timescales. “Utilities need to get electrons from point A to B. It will take them at least five to 10 years less to put batteries in a boxcar than to build a wire,” he tells me.
Whether SunTrain can succeed at scale is unproven. But it is an intriguing example of the possibilities of repurposing existing infrastructure, even that which is as neglected as the US rail network. It is still worth making big societal bets on transformative technologies, such as nuclear fusion or quantum computing, because the potential pay-offs are enormous. But it is also worth imagining better ways of adapting existing technology and infrastructure for more immediate impact.
Another case of repurposing old technology is wind propulsion, which humans have been using for six millennia. Earlier this year, the Finnish company Norsepower won a contract to fit six 35-metre tall rotating Flettner sails to a new fleet of ships chartered by Airbus. Last year, the agricultural trader Cargill chartered a Mitsubishi-owned ship retrofitted with 37.5-metre high rigid sails to supplement its engine. Some in the industry predict that such technology could cut ships’ fuel consumption by 30 per cent.
Perhaps the biggest gains from reimagining existing infrastructure are in the building sector, which generates about 37 per cent of harmful global emissions. A report last year from the United Nations Environment Programme estimated that new buildings the scale of Paris are being created around the world every five days. UNEP reckons that renovating existing buildings produces between 50 per cent to 75 per cent fewer emissions than new construction.
There are some wonderful examples of repurposed buildings: London’s Tate Modern is in a converted power plant and Paris’s Musée d’Orsay is in an old train station. My favourite example of a multi-use building is Amager Bakke, part of Copenhagen’s port area reconversion, a clean-waste incineration plant with an artificial ski slope.
Journalists like me tend to obsess about everything shiny and new. Sometimes, however, there is more value to be found in reimagining the old and messy.