Sales of electric vehicles (EV) have skyrocketed in recent years in response to a near-universal agreement that we must slow our polluting of the atmosphere. Electric vehicles produce zero emissions once on the road, but are they the best solution? Electric vehicles rely on lithium-ion batteries which are very similar to those that power our phones, tablets and laptops. Though the batteries have become more efficient over time, we are still using the same battery technology that was introduced to the commercial market back in the 1990s. As a result, many are looking to hydrogen as an alternative.
More concerning than the slow rate of progress are the far-reaching environmental consequences. The primary method of extracting lithium is to drill into salt flats and pump lithium-rich brine to the surface. Currently, the brine is left to evaporate and the lithium is collected months later. As demand increases, it is predicted that miners will choose to heat the brine, an energy-intensive process that releases more emissions.
Most of this drilling is done in the Lithium Triangle, a region covering Argentina, Bolivia and Chile. The mining of lithium in this way is known to destabilise water levels, causing problems in these South American countries that are already notoriously dry. Toxic chemicals like hydrochloric acid are utilised in the process, contaminating local water supplies and poisoning streams, and has resulted in the death of animals on a huge scale. In other regions, lithium is mined from rock, but this has similar detrimental effects to the environment. In the past, it has tainted the water that is used by local communities to irrigate crops, rendering them inedible.
With a single EV battery containing approximately 12kg of lithium, imagine the amount that would be required if all traditional vehicles were replaced with electric varieties. It’s clear that we must challenge our reliance on lithium.
Hydrogen is the most abundant element in the universe but is not found naturally occurring, so it must be produced to be used. Most hydrogen is currently termed ‘grey hydrogen’ as it is produced in a process called steam reforming that uses fossil fuels and so also produces carbon dioxide.
Some proponents of steam reforming suggest that we should shift to ‘blue hydrogen’ by capturing the carbon dioxide, thus eliminating the environmental impact. This, however, still requires the mining of fossil fuels, but there is an opportunity to use renewable energy sources to sustainably generate ‘green hydrogen’. Electricity from wind turbines or solar panels can be used to electrolyse (split) water into hydrogen and oxygen. The oxygen is vented, and the hydrogen stored. This option produces no emissions in the production of the gas and only requires the input of water, making it very sustainable.The preferred method of using hydrogen as a fuel source is in fuel cells. Hydrogen fuel cells introduce oxygen to hydrogen which combine to form water molecules – this reaction produces electricity that can power a motor. Utilising hydrogen as fuel produces only water vapour and heat as by-products, putting it on par with batteries for emissions. Although fuel cells and batteries both power a system using an electric current, they differ in important ways.
We have come to accept that batteries degrade over time. Your phone doesn’t last like it used to and equally, once you have had your electric car for a while, you will notice the mileage start to decrease. Hydrogen fuel cells offer a way out of this vicious cycle as they do not wear out. Fuel cells are more akin to traditional fuel in that they do not require charging. As long as there is a supply of hydrogen fuel, electricity can be produced. In fact, fuelling a car with hydrogen takes the same amount of time as filling up your petrol tank. All of this explains fuel cells’ lower operational costs than batteries.
Fuel cells are also remarkably efficient – more than twice as efficient as an internal combustion engine. That means that a fuel cell vehicle travels further on a tank of hydrogen than a car powered by gasoline. The reliability of fuel cells is also notably high. While batteries deteriorate at low temperatures and struggle to operate in adverse weather conditions, hydrogen fuel cells are unimpacted.
It has to be said that some experts believe we are about to hit a ceiling when it comes to the efficiency of lithium-ion batteries – we can only stretch this technology so far. When you take everything into account, a question is raised: why is hydrogen not being widely used to power vehicles?
You would not be surprised to hear that hydrogen fuelling stations are sparse. For hydrogen-powered vehicles to be widely accepted, there would need to be huge investment into hydrogen infrastructure. After all, a lack of charging points is one of the main things slowing mass adoption of electric cars. For comparison, there are 39 hydrogen refuelling points in the United States (35 of which are in California), compared with 26,000 charging stations.Critics of hydrogen fuel claim that the economic and technical challenges to implement ‘hydrogen highways’ (a reliable network of public refuelling stations) will take decades to overcome. Such a long timeframe makes hydrogen fuel less appealing to governments. Some believe that investing in hydrogen fuel is merely stealing resources away from other – supposedly more realistic – means of reducing our carbon footprint.
Storing and transporting hydrogen presents further challenges. Hydrogen is typically transported in either liquid or gaseous form via trucks, but the high combustion energy of the gas paired with its low ignition requirement make it extremely volatile. Safety measures must be strictly adhered to, but refuelling stations have exploded in the past.
These hurdles must be overcome if hydrogen is to become a dependable fuel source, but the lesser environmental impacts of green hydrogen compared with that of battery production and the mining involved should be enough incentive to strive for widespread hydrogen fuel adoption. Coupled with the clear benefits of hydrogen fuel cells over battery technology, more effort should be made to transition towards a hydrogen future. However, the long timeframe does pose an issue to our immediate climate crisis. Without serious government prioritisation, it seems unlikely that hydrogen will take off any time soon, but our heavy reliance on lithium is only going to cause more problems later down the line.