Electric cars and renewable energy: a 21st century dilemma?

It is commonly assumed that the growth of electric cars and of renewable energy go hand-in-hand. That may not be exactly so.

François-Xavier Chevallerau | March 8, 2017

The rise of electric cars and the deployment of renewable energy are often perceived as two faces of a same coin, i.e. the transition to a clean, sustainable energy future. Germany, often viewed as a pioneer of the energy transition, has announced ambitious plans for both electric cars and renewable energy. However, it cannot deliver both, according to an analysis by Dénes Csala and Harry Hoster from Lancaster University.

In October of last year, the Bundesrat, Germany’s upper legislative chamber, called for a phase-out of gasoline vehicles by 2030. Even if the phasing out of petrol and diesel vehicles is not yet official government policy, the Bundesrat resolution sends a strong signal concerning the probable future direction of the country’s car market. Other European countries are taking a similar path. Norway intends to phase out the sale of petrol and diesel cars by 2025, using a ‘polluter pays’ tax system, designed to incentivise the purchase of ‘low and zero emission vehicles’, and discussions on a similar plan are underway in the Netherlands.

Electric cars, however, are only ‘low and zero emission vehicles’ if the electricity that powers them comes from renewable sources. Otherwise, emissions of greenhouse gases (GHG) may not necessarily be reduced overall but rather displaced from vehicle use to the power generation level. An electric car running on power generated by coal or gas in fact generates more emissions than a car that burns petrol. Unless electricity generation from renewables can be scaled up to meet the additional electricity demand from a massively growing fleet of electric vehicles, the phasing out of petrol and diesel cars may lead to unintended consequences.

So what if Germany really decided to go 100% electric by 2030? According to Dénes Csala and Harry Hoster, it might actually be impossible to simply erase fossil fuels from both the energy and transport sectors at the same time. Replacing all internal combustion vehicles with electric ones would certainly lead to a huge reduction in the country’s energy needs, because electric cars are far more efficient – meaning that a much bigger share of the energy input goes into actual motion. But it would however require a staggering amount of new electricity generation.

Each year, German vehicles burn around 572 terawatt-hour (TWh)‘s worth of liquid fuels. Csala and Hoster calculate that a fully electrified road transport sector would use around 229 TWh. The planned phasing out of German nuclear power plants, by 2030 at the latest, will create an additional void of 92TWh to be filled. If renewables are to provide the electricity needed to power millions of cars, and that required to replace nuclear plants, a total of 321 TWh of new renewable generation will be required by 2030 – equivalent to dozens of massive new power stations. However, the German government is now putting the brakes on renewables in order to protect the stability of the electricity grid. Even if renewable energy expands at the maximum rate allowed by Germany’s latest plan, it will still only provide around 63 TWh of new power generation by 2030, leaving an enormous 258 TWh gap – the current total electricity consumption of Spain, or ten Irelands – to be filled by either coal or natural gas. Unless this electricity shortfall is filled almost entirely with new natural gas plants, a switch to 100% electric cars would result in a net increase in GHG emissions in Germany. If half of the necessary electricity for electric cars would come from new gas plants and half from new coal plants, the emissions of the road transportation sector would actually increase by 20%.

In order to achieve a substantial reduction in vehicle emissions, Csala and Hoster say, energy and transport policies must work in sync. To decarbonize its transport sector, Germany will thus need to step up its production of renewable energy instead of capping new solar plants or wind farms. Since this is still unlikely to be enough to deliver the totality of the new generation required, the country should also delay its nuclear phase-out and focus on getting better at predicting electricity demand and storing renewable energy.

What is true for Germany also applies, to a large extent, elsewhere. Last October, energy analyst Roger Andrews tried to assess how much more electricity we need to go to 100% electric vehicles, and what would be the cost of installing the required extra generation capacity. According to his calculations, replacing all of Germany’s 44,403,124 fossil-fuel-fired cars with electric ones would require a 31% increase in the country’s electricity generation and a 40% increase in its installed capacity. The cost of installing this extra capacity would be $232 billion. However, if Germany were to shut down all its coal and nuclear plants, it would have to install another 140GW of renewables on top of the 77GW of capacity needed to service electric vehicles, which would increase the installation cost to $650 billion.

According to Andrews, replacing the EU’s 250 million fossil-fuel-fired cars with electric vehicles would require a 34% increase in electricity generation and a 43% increase in installed capacity. The overall cost of installing this extra capacity would be $1.3 trillion. Requirements would, however, vary significantly from country to country. At global level, going to 100% electric vehicles would require an 18% increase in generation and a 30% increase in installed capacity, costing $5.0 trillion. These numbers would however increase to 26%, 44%, and $7.3 trillion if the number of vehicles in the world continues to grow at 2.7%/year through 2030.

Andrews calculations world.png

As Andrews points out, these numbers should be considered as ball-park estimates only, due to the uncertainties in the data and assumptions used. They however suggest that going 100% electric will come at a significant price for the energy system, and potentially for the climate in case the new generation capacity cannot be provided by renewables.

According to a Bloomberg New Energy Finance (BNEF) report form February 2016, sales of electric vehicles will hit 41 million by 2040, representing 35% of new light duty vehicle sales. This would be almost 90 times the equivalent figure for 2015. The electric vehicle sales for 2015 were up approximately 60% on 2014 at an are estimated 462,000. BNEF estimates that electric vehicles will cost the same as their gasoline-driven equivalents by the year 2022, the point from where, sale of electric vehicles are expected to really take off.


One comment

  • There’s an assumption we can build enough energy storage for at least a month to replace the natural gas used in electricity generation for long-term lack of solar and/or wind, as well as to quickly balance microsecond to seconds of intermittent fluctuations, and power generation itself. I make the case in my book “When Trucks Stop Running” that we cannot build enough energy storage to replace natural gas.
    Even if you disagree, this is clearly a long way off, longer than the time it would take to build all the solar, wind, energy, and transmission contraptions required, and there are probably not enough materials on earth to make the transition. Consider that techno-optimists Jacobson and Delucci (2015) estimate we’d need 335,422 onshore 5 MW turbines and another 154,387 offshore, 46,329 more utility-scale commercial solar PV facilities, 3,629 more CSP/solar thermal plants with storage, 207 more geothermal, 34,926 wave and 8,082 tidal (never mind that they’re still in pilot stage) and so on.
    So if we can’t replace natural gas (or coal), but we try to do so anyhow, there’s not only more pollution, but energy wasted.
    For example, I made the case that freight locomotives should not be electrified for many reasons, the main one being that diesel-electric locomotives are already electric and more efficient than all-electric locomotives:
    Instead of sucking electricity via hundreds of miles of overhead wires from a distant power station, diesel-electric locomotives have their own power generation plant on board—a 40 % efficient diesel engine (Hoffrichter, USDOE). The electricity generated onboard drives traction motors to move the wheels, with no mechanical connection between the engine and wheels, which is far easier, cheaper, and more efficient than pure electric locomotives (James 2011; Smil 2013). Electric locomotives get their electricity from inefficient power plants with a 32.8 % average efficiency, plus another 6 % loss over transmission and distribution lines. By the time the energy gets to the train wheels, you’ve lost 75 % of the energy, giving electric locomotives an overall efficiency of 22.9 %, which is 7.1 % less than diesel-electric locomotives (see detailed calculations). These electric locomotive calculations do not include the energy to construct new power plants and thousands of miles of overhead wires, substations, electric loading and unloading of train car and other infrastructure to deliver electricity to all-electric locomotives or replace diesel-electric locomotives.
    30 % Efficient Diesel-electric Locomotives: 40 % diesel engines × 92 % generator × 98 % rectifier × 92 % electric motor × 95 % transmission × 95 % traction auxiliaries (Hoffrichter 2012)
    22.9% Efficient Electric Locomotives: 100 % electricity at locomotive × 95 % feed cable × 95 % Transformer × 97.5 % Control system/power electronics × 95 % electric motors × 95 % transmission × 95 % traction auxiliaries (Hoffrichter 2012) × 32.8 % overall average energy efficiency of electric power generation plants × 92.4 % transmission and distribution losses (NRC 2015)
    There are many reasons besides energy storage that I discuss in my book about why a 100% renewable grid is unlikely, so efforts made to build one waste energy that could have been used to transition to a 15th century lifestyle.


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