Last month the UK government sprang a surprise by announcing a ban on the sale of all internal combustion engine cars and vans from 2035 – five years earlier than previously planned. No petrol, no diesels, and (depending on consultations) most likely no hybrids either. It sounds like a progressive, even daring, pro-environment policy. There is just one flaw: electric vehicles alone will do little to meet carbon emissions targets and restrain global warming. In a worst-case scenario, they could even increase emissions.
This is bad news if you nurse a rooted belief in the electric vehicle (or ‘EV’) argument. After all, there is so much to like about an electric car. In themselves they are clean, they are simple, and they are efficient. Simple machines last longer, and are intrinsically efficient (a pure EV drivetrain offers up to four times the energy efficiency of a comparable petrol driven car, according to the US Department of Energy).
And then they are quiet – so quiet that manufacturers actually have to add noise to make sure pedestrians can hear them. They emit no carbon dioxide and noxious particulates on the streets they travel. Finally if you happen to like power when you press on an accelerator, they have plenty of that: instantaneous torque in place of the laborious gear-driven hunt for motive energy that every internal combustion engine is condemned to. A top of the range Tesla Model S will take you from 0-60mph in 2.4 seconds, if that is what you want. What’s not to like?
What’s not to like is the Janus face of electric power. Every electric system has two poles, a positive and a negative. The positive is all about clean power, efficiency, sustainability. The negative is the reality of an EV in the world as it is: electric vehicles as they exist today and for the foreseeable future are costly, unreliable, and actually emit substantial amounts of carbon (it’s not possible to say for sure how much). In a carbon-warming world they could be part of the solution, but in themselves they are not the solution.
Consider: every new vehicle standing on a dealer’s forecourt has already emitted tonnes of carbon before it drives a single mile. This is the ‘carbon debt’, and it is a debt incurred and enlarged at every stage of the production process. For any vehicle there are supply chain carbon emissions to consider, all depending on how and where the many vehicle components were manufactured. For an EV there is an additional consideration, which is the power-hungry business of manufacturing batteries. The data on this (as on everything else to do with electric vehicles and associated carbon emissions) do not agree on the detail but at least there is consensus on the broad picture: a new electric vehicle carries a bigger carbon debt than a comparable internal combustion machine.
The promise of the electric future is that EVs will pay back this debt so rapidly that within a short time they will be making a positive contribution to reducing the carbon emissions that are due to transport – the fastest growing carbon generator in the UK economy. Yet this is highly debatable. Electric vehicles alone make no contribution to carbon reduction: they are only as good as the power economy they rely on. Everything depends on where the electricity to make them and power them comes from. Promoting EVs is not itself a carbon reduction policy (although it may be a substitute for such a policy).
And at this point where you need reliable consensus data on how an electric vehicle performs on the road you drive.
Most manufacturing operations and most EV charging systems rely primarily on grid energy, and it is easy enough to calculate the proportion of grid energy that is carbon free. In countries such as Norway, Sweden and France the electric grid is close to carbon free, due to the preponderance of nuclear and renewable energy. In the UK, renewables account for just over 38% of electricity generated. In the US, only 18% of power consumed is from renewable sources.
This matters not only for the ongoing carbon cost of powering electric vehicles, but also for their manufacture. Some EV producers promote themselves as low carbon-manufacturers – Tesla for example has publicised plans to make its Nevada Gigafactory (where it makes vehicles as well as batteries) fully solar powered, and VW-Audi has announced similar plans for its new EV plant in Belgium. But the reality of these plans is hard to establish – for example a drone photograph taken two months ago showed that less than 10% of the planned solar panel array at the Gigafactory had actually been installed.
The carbon emissions implied by the manufacturing supply chain are even harder to pin down. Most manufacturers have thousands of suppliers, each of which themselves may have many suppliers, making the true carbon cost of assembly almost impossible to calculate. This is one reason why the total lifecycle estimates of the actual emissions of EVs vary so wildly. In the last few years studies have come up with figures ranging from an emission total of around three times a typical petrol vehicle (a study from the University of Liege) to as little as one third of the emissions of a comparable internal combustion vehicle (a study by CarbonBrief, which brings together numerous academic specialists). Even VW itself – which of all the established manufacturers is making the biggest bet on EVs – recently published a study showing that its own e-Golf EV would have to be driven at least 74,500 miles before paying back its carbon debt and improving on a comparable diesel vehicle.
There are so many variables in calculating the carbon implications of EVs that it is near impossible to be certain that choosing a given EV over a conventional vehicle is an environmentally sound decision. Even if we assume that EVs can in fact emit less carbon over their lifetime, that still does not mean that they will do so. Everything depends on where and how far they are driven, and on how the power infrastructure to fuel them will evolve. It could even be that rapid transition to EVs increases emissions.
This is due to the nature of power generation. Most national power infrastructures include a mix of fossil fuel and renewable power sources: this is the case in the UK, where over half of electricity generation is from fossil fuels. A shift to EVs for transportation would mean that the existing power infrastructure would need to generate more, and that more capacity would also have to be built. Business and domestic use of electricity in the UK has been falling slightly for the last two decades, but energy consumption by transport has been rising fast – transport currently consumes almost three times the amount of energy produced by the electricity sector. Even allowing for a proportion of EVs charging overnight when electricity use is low, a total shift to electric vehicles would require a massive increase in power capacity – perhaps a doubling – with environmental costs (including carbon emissions) that would be significant.
And in the short term even a gradual shift to electric transportation means that the existing infrastructure will have to work closer to capacity. This almost certainly means more fossil fuel generation – renewable energy sources tend to be fully used, leaving fossil fuel generation as a buffer. When demand rises, carbon-emitting generation comes back on stream, and EVs end up increasing the output of CO2.
None of the above amounts to an argument against electric vehicles. Executed well and fed with clean energy, an electric vehicle makes much more sense than almost any alternative. But an electric vehicle is a downstream tool, largely dependent on decisions about subsidies, energy policy, and carbon costs. Announcing that EVs will become mandatory without creating a supporting policy framework is a merely political gesture. It will be interesting to see whether incentives to build such a framework begin to emerge in the forthcoming UK budget.
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