Hydrogen is the simplest and most abundant element on earth— it consists of only one proton and one electron. Hydrogen can store and deliver usable energy, but it doesn’t exist by itself in nature and is produced by separating it out from compounds that contain it – such as water, methane or other hydrocarbons from the ground.
Hydrogen cars either burn hydrogen in an engine or they react both hydrogen and oxygen together in a fuel cell. Both processes produce electricity which powers an electric motor. Hydrogen cars produce one harmless exhaust gas – water vapour.
Because the only pollution is water and steam, Hydrogen is an environmentally friendly alternative to fossil fuels which can be used to power just about any machine needing energy. The fuel cell is the energy conversion device that can capture and use the power of hydrogen effectively.
Advantages of Hydrogen (as used in fuel cells)
Clean Energy Source with no harmful emissions.
While it does take a lot of energy to separate hydrogen gas from its companion substances, the result is a powerful and clean energy source that produces one harmless exhaust gas – water vapour.
Fuel cells have the capacity to power any portable application that uses batteries – from hand-held devices to portable generators. Fuel cells power transportation such as cars, trucks, buses and even marine vessels; it can also provide auxiliary power to traditional transportation technologies.
Hydrogen has an important role in the future as a replacement for petroleum. In fact, several car manufacturers have designed vehicles that run on hydrogen fuel rather than petrol or diesel.
It is renewable.
Unlike other non-renewable sources of energy, hydrogen can be produced on demand – by breaking the water molecule to separate the hydrogen and oxygen atoms.
It is energy efficient.
Compared to diesel or petrol, hydrogen produces more energy for every kilogram of fuel. Hydrogen-powered fuel cells have two or three times the efficiency of traditional combustion technologies. For example, a conventional combustion-based power plant usually generates electricity at between 33 to 35 percent efficiency, while Hydrogen fuel cells are capable of generating electricity at 65 percent efficiency. Similarly, vehicles that use hydrogen fuel cells and electric motors, are more efficient as they can convert up to 65 percent of the fuel’s energy. As a result, there is more than 50% reduction in fuel consumption compared to petrol or diesel vehicles. Plus, fuel cells operate quietly.
Disadvantages of Hydrogen (as used in Fuel Cells)
It is expensive to produce.
While Hydrogen is found abundantly in nature, to separate it from the compounds it is found in is expensive and time consuming. Until technology is developed that can make the whole process a lot simpler and less costly, then hydrogen energy will continue to be an expensive option.
It is expensive to store and transport.
Transporting and storing hydrogen is relatively more expensive than oil or coal. Hydrogen fuelling stations generally receive deliveries of hydrogen by truck from hydrogen suppliers. An interruption at a hydrogen supply facility can shut down multiple hydrogen fuelling stations.
It is not easy to replace existing infrastructure.
Refueleing stations and storage tanks need to be built for Hydrogen usage and distribution on a wide scale.
It can be dangerous.
Hydrogen can be very flammable. Hydrogen gas burns in air at very wide concentrations – between 4 and 75 percent, and as it is stored in tanks high and is highly compressed, there’s always the risk of it leaking from tanks.
Hydrogen is currently produced from fossil fuels.
While the point of switching to hydrogen is to replace the use of fossil fuels, most hydrogen is currently being produced in reactions involving coal and natural gas, which emits Carbon Dioxide and is therefore considered “grey hydrogen.” The goal, though, is to produce hydrogen from low-carbon energy sources.
However, green Hydrogen
In the case of “green hydrogen,” solar panels or wind generators produce electricity that may need to be stored in a battery before it is used in an electrolyser to break down water into hydrogen and oxygen. The hydrogen gas is then highly compressed and stored in a cylinder or tank before it is piped into a fuel cell, which uses the hydrogen to create clean electricity with no harmful emissions.
In early 2020 the Australian Government announced support for a massive solar energy plant to make Hydrogen cleanly in Western Australia. It will make so much Hydrogen that a lot of it will be exported to other countries.
Investment Support is needed.
According to the Hydrogen Council, for the hydrogen economy to advance, it needs investment support of $70 billion by 2030.
The cost to produce and distribute hydrogen from clean energy sources is expected to fall by as much as 50% over the next decade. There are technological challenges, but if they are addressed, a clean future with hydrogen is closer than we think. Two key drivers are working in green hydrogen’s favour: the cost of renewables continues to fall, while the urgency to reduce greenhouse gas levels has increased following the Paris climate agreement. The cost of green hydrogen is expected one day to be on par with that of “grey hydrogen” from coal and natural gas.
Scaling up will also reduce the cost of electrolysers.
Molten Carbonate Fuel Cells (MCFCs) which operate at high temperatures and utilise cheaper, non-platinum catalysts to reform natural gas directly into hydrogen, can provide high-quality primary and back-up power to utilities and businesses. MCFCs can reach efficiencies of 70%-80% if located near the point of consumption
Corporate interest is a must, if we are to reach the Hydrogen Council’s investment goal of attracting $70 billion over the next decade. “Grey hydrogen” production is here, but “green hydrogen” production may be here sooner than we think, as the world scrambles to fulfill the terms of the Paris Agreement and as renewable energy prices fall.
Fuel Cell Basics
A fuel cell is a special kind of battery that generates electricity through an electrochemical reaction, not like a petrol burning combustion engine. In a fuel cell, hydrogen and oxygen are combined to generate electricity, heat, and water. Fuel cells are used today in a range of applications, from providing power to homes and businesses, keeping critical facilities such as hospitals running, and to power vehicles including cars, buses, trucks, forklifts, trains, and more.
A fuel cell is composed of an anode, cathode, and an electrolyte membrane. A typical fuel cell works by passing hydrogen through the anode of a fuel cell and oxygen through the cathode. At the anode site, a catalyst splits the hydrogen molecules into electrons and protons. The protons pass through the porous electrolyte membrane, while the electrons are forced through a circuit, generating an electric current and excess heat. At the cathode, the protons, electrons, and oxygen combine to produce water molecules. As there are no moving parts, fuel cells operate silently and with extremely high reliability.
Fuel cells do not need to be periodically recharged like batteries, but instead continue to produce electricity, as long as a fuel source is provided.
Because fuel cells generate electricity through chemistry rather than combustion, they can achieve much higher efficiencies than traditional energy production methods such as steam turbines and internal combustion engines. To push the efficiency even higher, a fuel cell can be coupled with a combined heat and power system that uses the cell’s waste heat for heating or cooling applications.
Fuel cells are also scalable. This means that individual fuel cells can be joined with one another to form stacks. In turn, these stacks can be combined into larger systems. Fuel cell systems vary greatly in size and power, from combustion engine replacements for electric vehicles to large-scale, multi-megawatt installations providing electricity directly to the utility grid.
