Petrol vs electric: MCN lifts the lid on the true cost of battery powered bikes

Love it or hate it, we’re seeing major developments in electric motorcycles. But the latest research shows that their environmental advantage over more traditional petrol-powered machines is far from cut and dried.

While it’s true battery vehicles have zero tailpipe emissions, they rely on the electricity grid – using power that might be clean wind or solar energy but could just as easily be from a dirty, coal-fired power station.

The manufacturing process of any vehicle, from mining raw materials to delivering them to showrooms, also contributes a hefty chunk of the total lifetime emissions figures.

For battery electric vehicles (BEVs) those manufacturing emissions are higher than for internal combustion engine vehicles (ICEVs) and it takes thousands of miles of use for a BEV’s carbon footprint to become smaller than an equivalent ICEV. And that’s not all…

Taking a moment to look at four wheels, a Volvo XC40 Recharge electric car’s battery accounts for only 16% of its mass but 28% of its carbon footprint in the manufacturing stage.

An electric bike’s battery can account for as much as 45% of its total mass so is likely to make up a larger percentage of its manufacturing carbon footprint. And since motorcycles typically cover fewer miles there’s less chance to hit the ‘break even’ point for climate emissions in use.

The European Environment Agency (EEA) 2021 report ‘Decarbonising Road Transport – the role of vehicles, fuels and transport demand’ points out that while BEVs can have a smaller climate impact than ICEVs over their lifecycle – thanks to lower CO2 emissions – their impacts on other environmental factors including “resource depletion, acidification, human toxicity or air pollution” can be higher.

Many of the EEA’s figures come from a 2018 study Life Cycle Assessment in the Automotive Sector from Francesco Del Pero from the Department of Industrial Engineering at the University of Florence.

It aimed to work out the total lifetime emissions of vehicles, including the manufacturing emissions, and found that it takes around 45,000km (that’s 28,000 miles for us Brits) for an electric car to ‘break even’ in terms of greenhouse gas emissions when recharged using typical European electricity supplies.

That figure varies depending on where you live – in Norway, with lots of green electricity, it takes only 18,600 miles, while in Poland, where coal-fired power stations are still the main source of electricity, electric cars didn’t break even at all before the study’s 155,000-mile cut-off point.

The Del Pero figures aren’t pessimistic outliers, either. Volvo did a direct comparison between their XV40 Recharge BEV and the standard, ICE-powered XC40 in 2020, comparing emissions in manufacturing and use, and found that the break even point came at 52,000 miles using typical European electricity supplies and 29,000 miles using wind-generated power.

In terms of other harmful impacts – such as the acidification of soil and water, ozone depletion, particulate emissions and ‘human toxicity’ (an index reflecting potential harm from chemicals released into the environment) – the Del Pero study revealed that BEVs were actually found to be worse than ICEVs over their entire typical lifecycle.

That’s largely down to the mining and processing of the materials in their electronics and batteries, such as copper, nickel, lithium, and cobalt – plus the emissions from the large number of ‘dirty’ power stations.

That might paint a bleak picture, but electric bikes still have a future. It’s ever-harder to squeeze fossil fuels from the earth and developments in batteries mean that they’re becoming greener.

Battery recycling – a fast-improving technology – means a growing proportion of lithium, nickel and cobalt can be recovered, and future batteries are under development with an eye to using more sustainable materials, and as power generation becomes greener around the world (greenhouse emissions from power generation in Europe have halved since 1990 and are projected to halve again by 2030) so does the eco performance of electric vehicles.

But it’s also clear that other low carbon or carbon-neutral ideas – hydrogen power via fuel cells or hydrogen combustion engines, for instance, or synthetic fuels – shouldn’t be ignored.

---

False ecology? The truth about electric motorbikes and the environment

First published 11 June 2020 by Ben Purvis

The message that electric vehicles are the zero-emissions transport of the future is impossible to ignore. We’re beaten over the heads with a constant stream of news that tells us internal combustion engines (ICE) are filthy while electrics are the utopian future.

Plans are already in place to pull new petrol and diesel cars and vans from sale by 2040, a date that could yet be brought forward to 2035, and while there’s no such deadline for motorcycles, it’s clear which way the wind is blowing. But does the data actually back up the messaging?

While an electric bike emits nothing from its nonexistent tailpipe, that’s just a small part of a vehicle’s whole-life emissions cycle. Add complexities like how electricity is produced and what is emitted during manufacturing and the picture is far murkier.

The hidden emissions

Although motorcycle-specific data is hard to come by, there’s a bank of info on electric cars that suggests electric bikes might not have the advantage you’d expect.

In 2018 the European Environment Agency compiled a report – Electric vehicles from life cycle and economy perspectives – which gives insight into the issues. Most importantly, it concluded that BEVs (battery electric vehicles) emitted 1.3 to two times as much greenhouse gas (GHG) during the production process as petrol equivalents.

The report said: “GHG emissions from raw material and production LCA [life cycle assessment] phases are typically higher for a BEV than for its ICEV equivalent. This is related to the energy requirements for raw material extraction and processing as well as producing the batteries.”

Warming the planet

With the electric vehicles considered for the report, the batteries alone accounted for around 40% of the greenhouse emissions in the production stage. On bikes, that percentage is likely to be higher as there’s simply less raw material in a motorcycle, making the battery a more significant chunk of the total.

According to figures in the EEA report, the batteries accounted for between 16% and 26% of cars’ total weights, while on electric bikes the batteries account for perhaps twice that much. For instance, Harley-Davidson’s LiveWire has a total weight 249kg, of which the battery is 113kg. That’s 45% of the whole bike.

Once production is finished electric vehicles don’t emit greenhouse gasses directly, but there are still emissions from electricity production. It varies from one place to another – in nuclear and hydro-electric-powered Sweden, electrics are estimated to emit the equivalent of 9g/km of CO2 while in Latvia, where electricity comes mainly from coal, it was 234g/km.

A study published in the journal Nature Sustainability found that even when electricity comes from poor sources, they do break even after a long time on the road. Large electric cars typically start to emit less than their petrol equivalents after around 44,000km.

Small vehicles need 70,000km to reach that point because their batteries account for a greater proportion of their production emissions and their petrol equivalents. 

Given that on an electric motorcycle the battery accounts for a larger proportion of the raw materials by weight, it will take even more miles before an electric bike’s overall emissions drop below the lifetime output of a petrol bike.

And there’s the sticking point. Battery cars make sense on the basis that the average car will cover 15,000km per year and last 12 years – giving a lifetime mileage of 180,000km. Given the smaller distances that motorcycles tend to cover, and that the electric bike break-even point may be north of the 70,000km needed for a small electric car to overhaul a petrol one, it’s far from clear that electric bikes are the true green option.

Electric will win in the end

While there are endless arguments for and against the switch to electric vehicles, a 196-year-old scientific theory means they will win the day.

Putting aside variables like how electricity is produced, the emissions from battery production and losses in storage and charging, electric motors have an advantage because they’re not heat engines and as such they’re not subject to ‘Carnot’s rule’.

Established by French physicist Sadi Carnot in 1824, the rule shows that a heat engine (anything that converts thermal energy to mechanical energy) has a maximum efficiency that can’t be exceeded. For petrol engines, Carnot’s rule puts that maximum at about 70%.

Even the most advanced petrol engines manage around 50% , but electric motors aren’t limited by Carnot’s rule. That means they can operate with efficiency levels of 95% or more. As improvements are made in reducing emissions from battery production, the pendulum will inevitably swing in favour of electric even bikes.