Jordan McGillis is a Paulson Policy Analyst at the Manhattan Institute. Before joining MI, Jordan was the Deputy Director of Policy at the Institute for Energy Research.
Sadiq Khan headlined June’s Climate Action Week with the announcement of a new Transport for London (TfL) plan to purchase wind and solar power for the Underground. Khan stated:
“This first step to powering the Tube network and TfL’s wider operations with 100 percent renewable source electricity is another crucial part of reducing carbon emissions and building a better, greener London for everyone.”
The £200,000,000 TfL tender stipulates that the electricity supplier will generate about 10 percent of the power TfL demands by no later than June 2026. The Mayor’s office intends to increase its purchases to meet 100 percent of TfL’s needs with renewables by 2030, in line with the Zero Carbon London Initiative.
But despite the rosy optimism, this plan is, at best, blusterous and, at worst, actively harmful. The danger of the Khan plan is two-fold. If pursued in earnest, it will fatally compromise London’s transport heart. If, more likely, it is pursued only on paper, the plan will deceive the public towards false beliefs about the viability of renewables.
The Tube’s power requirements are prodigious, totting up at more than 1.2 terawatt-hours annually, or roughly 3.5 percent of Greater London’s total electricity consumption. To meet that demand, TfL sources – via the Crown Commercial Service – electricity from the National Grid. In 2020, the UK’s electricity mix was made up mostly of natural gas and nuclear power; wind and solar came in third and fourth respectively, contributing about 28 percent of the country’s power when counted together.
While the 28 percent figure may be interpreted as supporting the Khan plan for 2026 and as putting TfL well on the way to all-renewables by 2030, the intermittent nature of wind and solar power mean that they alone cannot do the job. Early and late in the day—when the Tube is put to its greatest test—solar production is minimal or nonexistent. Wind often does not help either. Diurnal variation yields the biggest wind power output in the overnight hours, when Londoners are asleep and trains are preparing for the next day’s work. The Germans, as they so often do, have a word for this—Dunkelflaute—bemoaning wind and solar inadequacy.
One theoretical option to remedy the misalignment between wind and solar output and Tube usage would be for TfL to spend big on batteries, storing excess energy from overnight wind and midday sun to power the system when needed later. But given the physical and fiscal challenges to that approach, Sadiq Khan has opted instead to utilise a mechanism called a power purchase agreement (PPA).
Under a green electricity PPA, a buyer guarantees demand for wind and solar power output and a producer guarantees sales of it. The utility provider does the rest, taking renewables onto the grid when they are generated and serving the PPA buyer as normal. TfL therefore will continue to receive its power from the National Grid and will continue to benefit from the more robust and dispatchable resources. Sadiq Khan and TfL are garnering plaudits for signing the PPA, but it is natural gas and nuclear that will ensure the trains still run.
American tech companies like Apple turn the same trick. The California-based computer designer claims that it “has generated or sourced 100 percent renewable electricity for its corporate operations since 2018.” This gives the impression that wind turbines and solar panels like those that blanket the Cupertino headquarters’ rooftop are the company’s sole source of electricity; the reality is a more convoluted one in which Apple signs PPAs or builds new renewable facilities of its own, yet still in the end relies on the local utility for firm power.
Data centers, like the London Underground, cannot work only when nature complies.
The Khan approach, like Apple’s, is to burnish the city’s green reputation with PPAs, while still relying on the baseload power National Grid procures from reliable sources. It is the energy equivalent of publicly championing veganism, posting a hefty greengrocer’s bill, and yet privately starting each day with a full English.
The casual observer, as both Khan and Apple know, hasn’t the time to scrutinise the fine print and is apt to think the Tube really is powered by wind and that the latest iPhone really was manufactured using solar. This view is already circulating in the UK, as evinced by London Loves Business’s claim that the Tube could be, “powered entirely by renewable source electricity” by 2030.
Beyond the simple dishonesty of it, the long-term harm is that the casual observer is then more likely to support an unsustainable sprint to renewables. Public misunderstanding could soon lead to circumstances in which reliable natural gas and nuclear are crowded out from the energy market before adequate and cost-efficient battery storage becomes available. While wind and solar additions may cover the UK’s need in ideal conditions, when the pall of the Dunkelflaute sets in, the country will go dark.
Khan’s 100 per cent renewable plan for the London Underground can mean only one of two things. Either the Tube is powered fully by renewables, and inevitably fails due to the natural constraints of wind, solar, and batteries, or the Tube’s real energy use is concealed with opaque power purchase agreements.
Khan and TfL will opt for the latter, perpetuating the green energy farrago and making widespread system failure in the future more probable.