In order to compare the two types of vehicle it is worth understanding how each of the technologies works.
An electric car is powered by a lithium-ion battery, which supplies power to a motor to power the various parts of the vehicle. The batteries are recharged by plugging into the electricity grid, much as with any other electrical device, such as a computer or telephone. Some types of electric car can also provide themselves with a small recharge when braking by converting the heat that is produced into electricity.
Hydrogen cars also contain an electric motor, which is fuelled by hydrogen fuel cells which allows hydrogen to react with oxygen to create the chemical production of electricity and water vapour. The electricity powers the motor while the harmless water vapour is released into the atmosphere. Hydrogen fuel cell cars, also known as fuel cell electric vehicles, are refuelled with hydrogen at specific service stations that contain pressurised tanks of the natural gas.
There are a number of pros for both electric and hydrogen cars, which relate to the technologies themselves as well as the support and availability of each type of vehicle.
The infrastructure for electric cars is more advanced than that for hydrogen-powered vehicles. Governments around the world have been investing in infrastructure such as charging stations at existing petrol stations and motorway rest stops, shopping centre car parks and even on the side of some streets. The UK also offers grants towards the purchase and installation of domestic charging points.
Electric vehicles are also cheaper than hydrogen powered cars, while the cost of recharging is also less during off-peak grid times, making electric vehicles a good long-term investment.
Electric cars run silently and produce no exhaust fumes, meaning that there is no noise or air pollution, while they also consume no energy when stationary.
Electric motors are also reliable due to the lack of moving mechanical parts (when compared to combustion engines).
Hydrogen cars provide many similar benefits as electric cars, including the all-important lack of polluting emissions.
While the process to produce hydrogen gas can be complex, it is the most abundant element in the universe, meaning that hydrogen is a renewable fuel source.
Hydrogen cars are also much faster to refuel than electric cars, while also offering greater ranges than electric vehicles. For example, Renault’s Kangoo Z.E. Hydrogen and Master Z.E. Hydrogen have range extender fuel cells that deliver ranges of over 350 kilometres and charge times of just 5-10 minutes.
Despite the advantages afforded by electric and hydrogen cars, there are a number of drawbacks with both types of vehicle, although these can, and are, being addressed by industry.
Possibly the largest drawback with electric cars is the range compared to the amount of time it takes to recharge. This depends on the battery and the type of charging station that is being used, but generally-speaking the range and refuelling times make long-distance driving in an electric car more difficult than with hydrogen or traditional combustion engines.
While high-power charging stations allow for faster recharging, they can also more expensive to use. For example, in Germany, where charging stations bill per kilowatt-hour, high power charging stations are around ten euros more expensive per kilowatt-hour (usually 0.30 Euros per kilowatt-hour), but can be as much as 0.90 Euros per kilowatt-hour on non-partner networks. Recharging costs also vary between countries, with France charging 2.25 Euros to travel 100 kilometres (based on an average of 15 kWh per 100 kilometres), while the same distance would cost 3 Euros in the UK.
These issues can be mitigated against by the use of a hybrid electric/combustion engine system, where the traditional engine system can act as a back-up or support to the battery
The main problem with hydrogen cars is the lack of infrastructure to support their use. The lack of refuelling stations means that, for many, hydrogen vehicles are just not a viable option yet. However, it is believed that hydrogen infrastructure is easy to scale up and so, with the right investment and support, this problem could be solved.
The other main difficulty with hydrogen power is cost. Hydrogen-powered cars are not cheap and refuelling prices differ considerably between countries. For example, the cost of refuelling a hydrogen-powered car is four times that of recharging an electric car in the United States. However, this looks set to change too, with the cost of hydrogen fuel cells having already dropped by more than 80% in recent years.
Having seen the overall pros and cons for each type of vehicle, how do electric and hydrogen cars compare when examined on a number of key factors, such as range, charging, safety, emissions and cost?
With electric cars, the range is highly dependent on which vehicle you buy. The more expensive vehicles, like the Tesla Model S Long Range has a range of 375 miles compared to a real-world range of 150 miles for the less expensive Nissan Leaf Acenta.
Hydrogen fuel cell vehicles offer greater ranges and faster refuelling times too. The Hyundai Nexo, for example, can manage 414 miles and only takes five minutes to fill up, as opposed to the hours it can take to recharge an electric vehicle. However, hydrogen powered vehicles still tend to be expensive to buy as there are yet to be any models at the budget end of the market.
2. Charging/Refuelling Station Availability
Hydrogen fuel cell cars are not only more expensive than many electric cars, they are also have much less infrastructure when it comes to refuelling, with only around 400 hydrogen refuelling stations currently in the world (including private ones). There are, for example, just 16 hydrogen refuelling stations in the UK. This lack of facilities is a real drawback for hydrogen powered vehicles at the moment, while electric vehicles already have thousands of charging stations around across the globe.
Safety has been seen as a key concern for hydrogen fuel cells, due to the highly flammable nature of hydrogen gas, which burns in air at concentrations ranging from 4 to 75%. However, technological advances have resolved many of these potential safety issues. The Toyota Mirai, for example, uses a patented design to prevent hydrogen leakage as well as shutting off the flow of hydrogen in the event of a collision and store the fuel tank outside of the cabin so, in the unlikely event of a leak the gas will vent harmlessly up into the atmosphere. Because hydrogen is lighter than air, it diffuses directly up into space at the rate of 20mph, making it safe unless it is allowed to build up in enclosed spaces in large quantities.
Electric batteries also come with their safety concerns and challenges. If lithium-ion batteries are allows to overheat or overcharge they can cause injury. Plus, should there be a fire, the batteries can ignite and are difficult to put out as the fuel for the fire is not vented away as with hydrogen. Vehicle manufacturers have been working to solve these issues by regulating temperatures and using multiple sets of smaller batteries to avoid overcharging.
As with any fuel source, hydrogen and electric cars have their own comparable safety challenges.
While hydrogen and electric cars don’t produce emissions from their exhausts, they are not zero emission products as CO2 is released into the atmosphere during the various manufacturing processes.
Manufacturing lithium-ion batteries is an energy-intensive process, which, when added to charging-related emissions, equates to an average of 124g of CO2 per kilometre for a 100kWh battery. Manufacture of hydrogen fuel cells isn’t much better, with the Toyota Mirai fuel cell stacks equating to 120g of CO2 per kilometre, although this can be greatly reduced when renewable energy is used to produce the hydrogen.
Of course, this can all change as technology is developed for both hydrogen and electric vehicles.
5. Cost of Ownership
Electric vehicles can be expensive to buy, depending on the exact model and manufacturer, even with government grants to help support buyers and bring prices down. On top of the cost of the vehicle, owners may also need to pay a monthly battery rental price. As mentioned above, the more expensive the model, the greater the range it offers. So, while there are some ‘budget’ options available for prices of around £20,000 they do not compare to the higher end of the market (around £65,000). The upfront costs are mitigated against slightly by the cost of charging, being around £35 to fully recharge a 100kWh battery on a roadside charger in the UK and about £12 if recharging at home.
Hydrogen vehicles are more expensive than electric vehicles, with no budget options on the market currently, the price tag for a new hydrogen vehicle is comparative to that of a top end electric vehicle. In addition, the cost of refuelling is higher too, at around £50-75 for a full tank.
It seems that battery electric vehicles currently have the edge over hydrogen fuel cell vehicles, although much of the reason for this is the fact that hydrogen is not as developed as a technology. However, given time and further development could see hydrogen catch up even as electric vehicles continue to advance. This will, however, also require investment in infrastructure to support hydrogen fuel cell drivers.
Given this investment and future innovations to bring down the costs associated with hydrogen cars, there is every chance that they could challenge electric cars as the future of clean transport. However, perhaps the real answer lies in a shared landscape where both types form part of the future transport strategy. Of course, both types are less polluting than petrol or diesel, so should both be part of a green revolution.
So, what does the future hold for hydrogen and electric cars?
Both require further research and development, with electric vehicles needing efficient recycling of spent batteries, faster charging times and increased ranges. Hydrogen, meanwhile, needs improved infrastructure and reduced costs for extraction of hydrogen gas for fuelling.
In the meantime, hybrid options could prove to be a workable solution, but ultimately the goal is to replace combustion engines to provide a clean, green and renewable transport future.
There are several key differences between hydrogen and electric cars, with each having their own specific advantages and challenges. However, as these challenges are overcome and technology and infrastructure advances, they are both set to be viable options for drivers.
Automotive companies are already investing time and money into developing this next generation of electric and hydrogen-powered vehicles, so we can expect to see them becoming increasingly common on our roads.