What’s the difference between hydrogen and electric?
Hydrogen is the other sustainable alternative to the internal combustion engine. But don’t think of a hydrogen fuel-cell electric vehicle (FCEV) as anything like a battery-electric vehicle (BEV). Here are 10 significant differences (and some similarities) between both.
Both BEVs and FCEVs use electric motors to propel the car. The motor itself, however, derives its power from a totally different source. BEVs are powered by batteries, usually lithium-ion ones, which store energy. FCEVs get their power from a hydrogen fuel cell, which uses hydrogen as a fuel to generate energy. In addition to the fuel cell, an FCEV can have a battery to store energy.
Both FCEVs and BEVs produce zero tailpipe emissions. However, the energy for the fuel cell and the battery, respectively, may generate greenhouse gases. The electricity recharging the battery may derive from power plants burning fossil fuels. And most hydrogen is produced using natural gas, which is non-renewable. One solution is so-called ‘green hydrogen’, which uses wind, solar and other renewable sources of energy.
Batteries are more efficient than fuel cells, but on the other hand, hydrogen is more energy-dense than batteries. This is an advantage especially for heavy-duty, long-range transport. For a truck with an 800-km range, a hydrogen fuel-cell powertrain can weigh as much as two tons less than an electric one. In other words: hydrogen means longer ranges and heavier payloads.
EV range varies widely, based on the model you drive; from as low as 250 km to over 600 km for the newest and more expensive models. Hydrogen fuel cars easily equal or surpass that upper limit.
On a standard charger, it can take hours to fully recharge a BEV. An FCEV is recharged in a matter of minutes, significantly reducing downtime, which is especially interesting for vehicles with several shifts per day. Also, FCEVs are less sensitive than BEVs to cold temperatures.
A recent study (admittedly by the Hydrogen Council) suggests that decarbonizing medium to heavy transport is cheaper with hydrogen fuel cell technology than with battery-electric technology. In a number of crucial use cases, batteries were less attractive due to their larger size, higher weight, greater cost, and longer recharging times. Advances in hydrogen technology are rapidly bringing down the cost, associated mainly with expensive catalyst materials such as platinum. However, TCO for hydrogen cars still far exceeds that for their electric equals.
Both FCEVs and BEVs have their own safety risks. With a density 14 times less than air and the highest energy content per unit of mass of all fuels, hydrogen is extremely lightweight and highly flammable. This requires complex control systems. In BEVs, the main issue is heat management. This can result in so-called thermal runaway, which in some cases leads to fires which are hard to extinguish. However, both FCEVs and BEVs are very safe, and such malfunctions are vanishingly rare.
While the infrastructure to recharge BEVs is currently being rolled out at rapid clip, hydrogen refueling infrastructure still has to begin from nearly zero. Just over a year ago, there were less than 1,000 hydrogen refueling stations in the world. In other words: hydrogen is still stuck in the chicken-and-egg phase: not enough hydrogen cars, so no point building expensive hydrogen fuel stations. Not enough hydrogen fuel stations, so no point in buying a hydrogen car.
Perhaps the most obvious and relevant difference between FCEVs and BEVs is one of popularity. Electric vehicles are going mainstream. One in seven vehicles sold worldwide are now electric (either BEV or PHEV). In comparison, the number of FCEVs is minuscule. According to recent figures by the International Energy Agency, there were just 40,000 hydrogen-powered vehicles in use just over a year ago.
The best way to look at the differences between FCEVs and BEVs is not to see them as rival technologies, but as complementary ones. Depending on the needs, demands and conditions of certain transport issues, either FCEVs or BEVs will be the better answer. With the present state of technology and infrastructure, hydrogen will be the powertrain of choice mainly for light and heavy commercial vehicles, and this in areas where refueling is feasible.