What will be the future energy source for road vehicles?
I recently had a couple of points put to me that I am addressing in this article. Firstly, ‘why should I change my Jaguar sports car for an electric car? My transport carbon footprint with the 2,000 annual milage I do will be significantly less than if I changed to a new electric car as it would have a higher manufacturing carbon footprint’. And secondly ‘how do I compare the cost of buying and running an electric car against a fossil fuel car?’.
ERA’s recent membership survey results indicated that members wanted more information on petrol/diesel versus electric versus hydrogen. Here I provide an update on developments in powertrain energy systems (the systems used to propel vehicles) for road vehicles, as the technologies for all such systems have been developing at a fast pace. This is happening in the context of the banning of manufacture of new petrol and diesel cars by 2030 and hybrids by 2035.
When making comparisons between powertrain energy systems it is important to ensure that the comparison is like for like and not to fall into the trap of comparing apples with pears. The news media often make sweeping statements in this area which can fail to tell the whole story. A common one of late is that electric cars have a higher carbon footprint than conventional cars because of the materials used in their batteries, and another that as they are heavier they create more tyre and brake dust particulates. This ignores the important fact that electric cars have regenerative braking which can significantly reduce the creation of brake dust particulates.
The first question above moreover only refers to carbon footprint when burning fossil fuels also creates other pollutants harmful to the environment and human health:
Air quality and health
The Air Quality Expert Group’s report ‘Exhaust Emissions from Road Transport’ published in 2021 states, ‘Air pollutants in the exhaust emissions from internal combustion engine (ICE) vehicles result from unburnt fuel, high temperature combustion of fuel in the presence of air, and from exhaust after treatment processes’. It goes on to say, ‘Whilst there has been considerable success in substantially reducing exhaust emissions of pollutants such as carbon monoxide (CO), hydrocarbons (HCs) and particulate matter (PM), exhaust emissions from ICE vehicles remain a major source of nitrogen oxides (NOx) and an important contributor to poor urban air quality.’
Frequently in the past vehicle manufacturers’ emission data for compliance under European Emissions Standards was based on emissions tests undertaken in laboratory conditions, not under real-world driving conditions where it is well documented that vehicles create greater harmful emissions than under laboratory conditions.
We cannot ignore methane as a significantly environmentally damaging gas. The extraction and processing of fossil fuel results in the release of methane. While carbon dioxide is more abundant and longer-lived, methane – the main component of natural gas – is far more effective at trapping heat while it lasts. Over the first two decades after its release, methane is more than 80 times more potent than carbon dioxide in terms of warming the climate system.
Stanford University’s Stanford Earth Matters magazine states, ‘Stanford-led research shows global emissions of methane from human activities have barrelled upward in recent decades, with fossil fuel sources and agriculture powering the climb. Other studies have shown how to improve estimates of methane leaking from oil and gas operations, outlined a process for converting the gas into carbon dioxide, and highlighted the climate impact of oilfields that routinely burn, or flare, natural gas - see also this link.
Recent studies of respiratory illnesses and diseases in low emissions zones (LEZs) and ultra low emission zones (ULEZs) show they have significantly declined since these zones were introduced. See pages 21 and 32 of this PhD thesis from University of York. It says:
‘We have shown that LEZ leads to a 7% reduction in limiting health problems. This effect is stronger in the second phase of LEZ, where we have also observed a 4.6% reduction in the incidence of long-term health problems and an 17% reduction in the probability of asking sick leave. The impact of ULEZ on health is even more pronounced, as we have found a reduction in the probability of having long-term health problems by 22.5%, number of health conditions by 29.8% and sick leave by 17.7%. ULEZ has also improved feelings of happiness, worthiness, and satisfaction by 1.3%, 1.3% and 1%, respectively. ULEZ also reduced anxiety by 6.5%.’
Other studies have been undertaken in Germany and Australia - see references at the end of this article.
Developments in battery electric vehicles (BEVs)
As a family who own an electric car, we were well aware of the pros and cons of having an one before purchasing it, in particular the lower mileage range, and the lack of public charging infrastructure.
As previously stated, the go-to concern for many in the media is the manufacturing carbon footprint of a BEV. My research before we bought ours looked at the lifetime carbon footprint of a BEV compared to that of the average fossil fuel internal combustion engine (FFICEV) of equivalent size and performance. Life cycle is defined as including manufacturing, servicing, fuel/energy, and disposal of the vehicle.
The consensus of opinion of the academic research which I examined revealed that on average the BEV’s carbon footprint over the life cycle of the vehicle is on average 50% less per kilometre travelled per year than FFICEV.
A very useful source of information if you are considering buying an electric is this guide from the Department for Transport.
Currently BEV batteries are made from a combination of raw materials. Base metals such as aluminium, copper and iron are important components, but the most expensive materials are precious metals such as cobalt, nickel and manganese, along with elements such as graphite and lithium. The manufacturing processes involved in converting such materials into batteries is included in BEVs’ carbon footprint, but as yet I have not found details what other pollutants there are that can potentially negatively impact on the environment, human health and biodiversity.
There are also huge problems with some of these materials that make up today’s electric vehicle batteries. As production ramps up, these urgently need to be fixed. Cobalt production is linked to child labour in the Democratic Republic of the Congo. Some Indigenous communities are resisting lithium mining on their land in South America. This from the RAC is worth reading.
The other argument against BEVs is, what happens when they come to the end of their life? But if charged properly batteries are expected to last in excess of 100,000 miles. Think also of the number of these types of batteries in your phones, your laptops and a whole range of electronic devices.
The mileage range of electric cars is dependent on many factors: the speed you drive, how you use the car, how much you use eco or sport mode or regenerative braking mode. In simple terms regenerative braking is when the electric motor becomes a generator to charge the battery every time you release the accelerator - in effect it acts as a brake, which reduces the conventional brake system wear and tear.
Other factors to consider include the number of additional electrical accessories the vehicle uses, how hot you have the heater, how often you use the air conditioning, the screen wipers, headlights, heated screens and seats etc. In winter the range drops because lower ambient temperatures can cause the battery to lose charge. We estimate the range of our car, which is 18 months old, drops from about 195miles on a full charge to about 165 miles.
Manufacturers are developing sodium-ion batteries. Like lithium-ion batteries they use a liquid electrolyte; instead of lithium, they use sodium as the main chemical ingredient. Sodium-ion batteries could cut costs because they rely on cheaper, more widely available materials. At the moment they are in their development phase, and as yet it is still to be determined if such batteries will be able to match lithium-ion batteries for range and charge times.
Public charging infrastructure rollout is currently too slow to keep up with expected growth in BEVs. Fortunately in the time we have owned our car we have managed with home charging. It takes about 12 hours for a full charge on a normal 13-amp supply and 5 hours on the medium speed charger which we can set to come on between midnight and 7am when there is less demand on the national grid.
National grid capacity also needs upgrading to cope with the future demand for electricity, and there is nimbyism when it comes to what is needed to increase grid capacity in order to transfer electricity generated at sea to where the consumer needs it.
Hydrogen
Last July I wrote about hydrogen in terms of how it is generated, the rare materials required for electrolysers, the vulnerability of those supply chains, its benefits and disadvantages and whether hydrogen fuel cell electric vehicles (HFCEVs) are the future in the UK.
The issues with HFCEVs as stated in that article are that they also require expensive rare earth materials. There is significant ongoing laboratory research and development in creating less expensive man-made materials to use in electrolysers, but as yet there is no significant scaling up of production and field trials of these materials to see if they are reliable, durable and economic to produce. In UK there is no strategy for a refuelling network. In July last year there were 11 refuelling stations and since then Shell announced the closure of six of theirs.
Water and electricity are the main requirements to create hydrogen. The UK is a water stressed country as a consequence of climate change and lack of investment in creating reservoirs. At the time of writing in some areas of UK the reservoirs are less than 50% of their capacity. When we have torrential rai the water runs off the land into the rivers, and ultimately to the seas, not into the aquifers and reservoirs.
Seawater is an alternative but as it is corrosive to the materials used in an electrolyser, desalination is required. Again a lot of research is being undertaken to develop materials that can resist corrosion from salt water, and desalination also requires a significant amount of electrical energy, but there are no significant large-scale production and trials of these materials to see if they are reliable and economic to produce.
For hydrogen production to be truly CO2 free it needs significant increases in use of renewable electricity, requiring wind and solar generation on a much larger scale than currently exists, but further scaling up is all too frequently limited by nimbyism, and political ideology which in turn deters private investment.
Hydrogen Internal Combustion Engines (HICE)
Vehicle and engine manufacturers such JCB excavators, Cummins Engines, Toyota, and Hyundai are in the process developing internal combustion engines using hydrogen as fuel, with the aim to have them on the market within the next two to five years.
The same issues apply in terms of hydrogen generation and supply infrastructure as previously stated. Such vehicles will also have to mitigate the small amount of toxic gases that are created as result of the combustion process, the oil vapours from the engines lubrication system are created by high combustion temperatures. These vapours will burn because the gas seal between the cylinder walls and the combustion chamber cannot be 100% effective. Whilst such engines should not in theory create CO2, they will still generate particulate matter which is damaging to the respiratory systems of all living beings.
The low energy density of hydrogen, it is argued (it is beyond the scope of this article to discuss relative energy density and specific fuel consumption in relation to power train output), is an issue when compared to fossil fuels which would require a larger volume of tank capacity to store enough hydrogen to achieve equivalent performance and range. There are currently also concerns about safety and the potential for an explosion in the event of an accident.
Synthetic e-fuels
Some European manufacturers are lobbying the EU for internal combustion engine vehicles to be allowed to be manufactured post 2035 if they are able to only run on synthetic e-fuels, but there are opposing views as to the viability and eco credentials of e-fuels. Note: hydrogen is a key requirement for this process as this article explains. For further reading also follow this link.
Summary conclusions
‘Why should I change my Jaguar sports car for an electric car?’
I hope I answered this question. It is not just carbon footprint. It’s the harm to human health that has to be considered, the impact on the health services, individuals’ income and life expectancy must all be part of the equation when deciding on how we travel.
‘How do I compare the cost of buying and running an electric car against a fossil fuel car?’
Deciding on what car to buy has a range of costs, such as purchase price, cost of maintenance, the cost and availability of fuel/energy, depreciation, insurance, etc and most important environmental cost.
The only advice I can give is that to make a comparison it must be the exact same make, model and specification (including energy hungry electrical accessories as previously mentioned), with equivalence in powertrain performance, be it electric, fossil fuel, hydrogen, hybrid, or Synthetic e-fuel and their potential negative impact on the environment, human health, biodiversity. and whether or not it meets your needs not your desires.
From personal experience an electric car meets 90% of our need for getting from A to B but it might not suit some people’s lifestyle unless they are prepared to change their behaviour and adapt to save this planet for the generations to come.
It is argued that BEVs are only a stepping stone from FFICE to hydrogen-fuelled vehicles. That may be so. I am sure over time batteries can be made from less environmentally damaging materials, but can we generate green hydrogen from renewables to be truly zero CO2?
I have discussed some of the innovations to replace FFICE, together with obstacles and issues that will need to be overcome and how all this might impact on how our vehicles are powered in the future. It’s a complicated picture. The one thing we can all do as individuals is to choose to travel less by car, and when we do need to do so to consider car sharing, use public transport increasingly and certainly reduce the number of flights we take.
Glossary of terms and abbreviations used in this article:
Fossil Fuel Internal Combustion Engine Vehicle (FFICEV)
Battery Electric Vehicle (BEV)
Hydrogen Fuel Cell Electric Vehicles (HFCEV)
Hydrogen Internal Combustion Engines (HICE)
Synthetic Fuel Internal Combustion Engines (SFICE)
Power Train Systems (PWT) encompasses FFICE, BEV, HFCEV, HICE, SFICE
Additional references
The health impacts of petrol and diesel cars
London Assembly article on ULEZ savings for NHS
Health benefits of London ULEZ
BMJ on health and low emissions zones