WHY YOU SHOULD CARE ABOUT HYDROGEN POWERTRAINS
When most of us think about sustainable development and our future energy consumption we accept that we need to play our part, but inside we groan about how the future isn’t what it used to be.
We assume deprivation and scarcity. It’s hard to get excited about a future that feels like we’ll be worse off.
Hydrogen as a source of sustainable energy is talked about in technical circles but hasn’t captured the consumer’s imagination in the same way as lithium-ion batteries. It doesn’t get the same attention in the general press. Shame, because it is a key piece in the net zero emissions puzzle. It’s actually something to get pretty excited about.
In this post we’ll make the case for why you should care about hydrogen powertrains.
Why Should You Care?
First off, what’s in it for me? It’s a fair question. If you own an EV you’re already doing your part.
Right?
Short answer: Yes, you are. Your trip to the shopping centre is green...
…but the things you buy are delivered to the shop in an articulated diesel truck that does about 9mpg. That is hardly your fault, but it is still a problem we need to solve.
All those trucks carrying freight is a very hard area of economy to decarbonise and represents almost a third of transport greenhouse gas emissions – 29.4% to be precise according to the International Energy Agency.
So What Can We Do About Big Trucks?
Happily, it’s not all doom and gloom. Hydrogen has the near-term possibility of powering large ground transport like HGVs and large SUVs, light aircraft like helicopters, and small-to-mid sized boats, as well as offering the opportunity to store the ‘free’ energy created by wind, solar and wave when they are generating more energy than the grid needs (such as wind turbines at 4am).
The Orkney Islands are a great example of the immediate benefits of hydrogen. Finding that in periods of low grid demand its local wind turbines were being switched off, the Orkney community decided to invest in hydrogen production facilities so the otherwise wasted wind energy could be used to make and store green hydrogen, in effect capturing and storing the energy of the wind.
As a result, the Orkney Islands now have an abundance of green hydrogen available to provide household electricity, recharge both hydrogen fuel cell and battery electric cars, and power the local ferry. They are even planning to use hydrogen to fuel the passenger and cargo aircraft which serve the islands.
What’s So Great About Hydrogen?
Hydrogen is nature’s battery, the lightest and most plentiful element in the Universe. It provides endlessly recyclable and scalable energy storage. When green hydrogen (that is hydrogen manufactured with green electricity from wind, waves, and solar energy) is used to power vehicles there are zero CO2 emissions.
The amazing thing about hydrogen is that is has a genuinely circular energy cycle. Green hydrogen in made by splitting water (H2O) into hydrogen and oxygen. The hydrogen is used in a fuel cell to generate electricity, and the used hydrogen then recombines with oxygen to form more water. Long after we have exhausted every resource from below the Earth’s crust, hydrogen will remain the most abundant element in the Universe.
Is Hydrogen Safe?
In short: Yes. Very.
Hydrogen is a colourless, odourless, tasteless and non-toxic gas. It has been studied extensively for decades and safe handling is well understood by engineers. In fact, it is safer than the fuels we’ve used to power vehicles for the last 100+ years.
Hyundai produced this video to explain hydrogen safety versus other fuels
Hydrogen is stored in pressure vessels, like the red gas canisters used to power heaters. Like any flammable gas or liquid, it can explode, but a pressurised hydrogen tank is a lot stronger than a petrol tank, and a lot less likely to rupture in the case of an accident. It is also designed to leak before it bursts: in the unlikely event that a crash puts too much pressure on the tank, it is designed to crack rather than burst, so the non-toxic hydrogen escapes slowly into the air.
Hydrogen tank gunshot test conducted by Toyota
Hydrogen is highly flammable but, due to the fact that it is far lighter than air, any escape goes up quickly into the atmosphere.
Vehicle Safety Car Bur Test Video
Here’s an interesting excerpt from the NASA archives Liquid Hydrogen As A Propulsion Fuel, 1945-1959:
“Tests were devised in which tanks containing liquid hydrogen under pressure were ruptured. In many cases, the hydrogen quickly escaped without ignition. The experimenters then provided a rocket squib (a small powder charge) to ignite the escaping hydrogen. The resulting fireball quickly dissipated because of the rapid flame speed of hydrogen and its low density. Containers of hydrogen and gasoline were placed side by side and ruptured. When the hydrogen can was ruptured and ignited, the flame quickly dissipated, but when the same thing was done with gasoline, the gasoline and flame stayed near the container and did much more damage. The gasoline fire was an order of magnitude more severe than the hydrogen fire. The experimenters tried to induce hydrogen to explode, with limited success. In 61 attempts, only two explosions occurred and in both, they had to mix oxygen with the hydrogen. Their largest explosion was produced by mixing a half liter of liquid oxygen with a similar volume of liquid hydrogen. Johnson and Rich were convinced that, with proper care, liquid hydrogen could be handled quite safely and was a practical fuel — a conclusion that was amply verified by the space program in the 1960s. At the time, however, Johnson and Rich filmed their fire and explosion experiments to convince doubters.”
How Do Hydrogen Fuel Cells Work?
People often think of a fuel cell electric vehicle (FCEV) as being a competitor to a battery electric model (BEV), but they are actually closely related. While a BEV stores the electricity in a battery, an FCEV uses a fuel cell to generate electricity from hydrogen. Every other part of the powertrain (motor, transmission etc.) is identical for both types of vehicle.
The obvious advantage of the fuel cell car is that it is not limited by the size of the battery – the fuel cell will generate as much electricity as the hydrogen tank will allow. As hydrogen is so light, just 10kg of hydrogen will give around 400 miles of range. In contrast, a typical battery electric car would need over 500kg of batteries to cover that distance.
JD Power offers a helpful description of how hydrogen fuel cells work in more detail:
A fuel cell has an anode, cathode, and an electrolyte membrane. It creates an electric current by passing hydrogen through the anode and oxygen through the cathode. At the anode, a catalyst splits the hydrogen molecules into electrons and protons. The protons pass through the porous electrolyte membrane, while the electrons are forced to a circuit as an electric current. At the cathode, the protons, electrons, and oxygen combine to produce water, plus some waste heat which can be used to warm the interior.
Are Electric Vehicles Better Than Hydrogen Vehicles?
Both BEVs and FCEVs will be important in our clean energy transformation. One isn’t necessarily better than the other – they have different strengths for different applications.
An easy rule of thumb is that when either weight, or power-to weight, is critical, hydrogen starts to look very attractive.
An example of the weight issue would be a 40-tonne truck, which would be very difficult to power using batteries. The batteries alone would weigh over five tonnes, cutting the amount of goods carried by each truck by 20% – or, to put it another way, increase the number of trucks on the road by 20%. In contrast an FCEV truck would have the same payload as a diesel truck, as the weight of the fuel cell would be no more than the weight of a diesel engine.
An example of power-to-weight would be an aircraft or a supercar. Aircraft (airliners and, even more so, helicopters) need the highest possible power-to-weight ratios: Airbus calculated that a battery-electric A320 would have a range of under 100 miles. Supercars also need to be reasonably light if they are going to provide a great driving experience. Current BEV supercars typically weigh two tonnes – a 700kg penalty which does nothing for handling or steering.
There is no single point when an FCEV makes more sense than a BEV, but it is easy to establish some principles. No-one is going to put a fuel cell into a power drill, as batteries work perfectly well. An electric motorcycle or a small car is likely to stay with batteries, because the batteries are relatively small. Once a car gets much above two tonnes, fuel cells start to look interesting as, say, a BEV Range Rover would weigh over three tonnes, with over half a tonne of batteries (which is why JLR has started a research programme into FCEV SUVs). Once you get to large commercial vehicles, FCEVs look like the only game in town.
Batteries Suffer from Mass-Compounding
Batteries have a big disadvantage in terms of weight per KW of power. Fuel cells are much lighter – their weight per KW is broadly comparable with a similarly powerful internal combustion engine.
Batteries suffer on two fronts as vehicles get larger.
Lithium-ion battery technology depends on mining and refining limited resources, which is itself an environmental issue, as well as a supply issue. While part of the solution, batteries are not sufficiently scalable to meet the global demand for energy storage.
They also suffer from what’s known as mass-compounding – meaning, to go further, faster or carry a heavier load, the battery has to be made bigger, which then adds to the weight, which means yet bigger batteries, and so on.
So, if the required battery pack is not too heavy (anything from a power-tool to a city car) then batteries make complete sense. Conversely, if the task is to drive a 40-tonne truck for 500 miles, then batteries are a non-starter.
A key strength of green hydrogen technology is its ability to reduce dependence on lithium, meaning reducing reliance on a limited, non-renewable resource that requires mining and a potentially fragile supply chain.
What are the Applications for Hydrogen Powertrains?
Viritech, along with many other cleantech companies, believes passionately in hydrogen’s role to reverse climate change.
Our focus is on areas where hydrogen fuel cells offer immediate benefits — where power, range and duration requirements increase, or long-term energy storage is required. We are developing powertrains for high-performance vehicles, heavy transport/equipment, aircraft, boats/ships and off-grid energy.
The Apricale® is the first hydrogen Hypercar under development by Viritech. Learn more about this exciting vehicle and Viritech’s technology.
Hopefully we’ve convinced you that you should care about hydrogen powertrains:
Hydrogen is a key part in the Zero Emissions puzzle.
Hydrogen technology addresses hard to decarbonise parts of the transport sector, like high performance vehicles (think motor racing), HGVs that move consumer goods around the country, aircraft, boats and off grid energy.
Hydrogen fuel cells are a safe, trusted and tested technology.
Hydrogen fuel cells are complementary to lithium-ion batteries.
Hydrogen is nature’s battery – endlessly renewable.
We’d love to hear what you think, get in touch info@viritech.co.uk
#fuelcellev #cleantech #hydrogenpowertrain
