Hydrogen fuel cells use hydrogen as a fuel in an electrochemical process that combines hydrogen and oxygen to produce electrical energy and water. The reverse process of electrolysis, which produces ‘green’ hydrogen and oxygen from water, can use a range of renewable energy resources (wind, wave, solar) to produce hydrogen as a fuel for renewable power generation. There is also growing interest in hydrogen power as a uniquely clean energy source that can produce heat and whose only by-products are water.
Green hydrogen produced from electrolysis (a high energy process) and renewable energy sources is a high cost option, which only accounts for around 5% of total H2 production. Currently, the vast majority of global hydrogen production derives from fossil fuel sources (methane gas reforming) and will continue to do so for several decades. However, as manufacturing capacity for more efficient and cost-effective electrolysers grows, it is expected that costs of production will fall markedly alongside roll-out of maturing renewable power generation technologies and capacity.
In order to produce a secure, resilient and decarbonised energy system, production and bulk storage of hydrogen will play an important role in balancing intermittent supply of energy from renewable energy sources with end-user demands (ie. for grid electricity, domestic and industrial heating and fuel for transportation).
Debates continue regarding hydrogen fuel cells advantages and disadvantages, but despite current limitations, hydrogen is still an environmentally-friendly alternative to fossil fuels and can be used to provide flexible and high-density power and propulsion for a wide range of industrial plant and modes of transportation using hydrogen fuel cell technology (often
Hydrogen fuel cell technology presents several advantages over other power sources , including:
1. Renewable and Readily Available
Hydrogen is the most abundant element in the Universe and despite the challenges associated with its extraction from water, is a uniquely abundant and renewable source of energy,perfect for our future zero-carbon needs for combined heat and power supplies.
2. Hydrogen is a Clean and Flexible Energy Source to support Zero-Carbon Energy Strategies
Hydrogen fuel cells provide an inherently clean source of energy, with no adverse environmental impact during operation as the byproducts are simply heat and water. Unlike biofuel or hydropower, hydrogen doesn’t require large areas of land to produce. In fact, NASA have even been working on using hydrogen as a resource with the water produced as a byproduct being used as drinking water for astronauts. This shows that hydrogen fuel cells are a non-toxic fuel source and therefore superior in this way to coal, natural gas and nuclear power which are all either potentially dangerous or hard to obtain. Production, storage and use of hydrogen will play an important role in driving further development of renewable energy, by balancing their intermittent supply modalities with the challenging end-user demands, avoiding the need for significant early investment to upgrade grid infrastructure.
3. More Powerful and Energy Efficient than Fossil Fuels
Hydrogen fuel cell technology provides a high-density source of energy with good energy efficiency. Hydrogen has the highest energy content of any common fuel by weight. High pressure gaseous and liquid hydrogen have around three times the gravimetric energy density (around 120MJ/kg) of diesel and LNG and a similar volumetric energy density to natural gas. These
4. Highly Efficient when Compared to Other Energy Sources
Hydrogen fuel cells are more efficient than many other energy sources, including many green energy solutions. This fuel efficiency allows for the production of more energy per pound of fuel. For example, a conventional combustion based power plant generates electricity at 33-35% efficiency compared to up to 65% for hydrogen fuel cells. The same goes for vehicles, where hydrogen fuel cells use 40-60% of the fuel’s energy while also offering a 50% reduction in fuel consumption.
5. Almost Zero Emissions
Hydrogen fuel cells do not generate greenhouse gas emissions as for fossil fuel sources, thus reducing pollution and improving air quality as a result.
6. Reduces Carbon Footprints
With almost no emissions, hydrogen fuel cells do not release greenhouse gases, which means they do not have a carbon footprint while in use.
7. Fast Charging Times
The charge time for hydrogen fuel cell power units is extremely rapid, similar to that for conventional internal combustion engine (ICE) vehicles and markedly quicker in comparison tobattery-powered electric vehicles. Where electric vehicles require between 30 minutes and several hours to charge, hydrogen fuel cells can be recharged in under five minutes. This fast charging time means that hydrogen powered vehicles provide the same flexibility as conventional cars.
8. No Noise Pollution
Hydrogen fuel cells do not produce noise pollution like other sources of renewable energy, such as wind power. This also means that, much like electric cars, hydrogen powered vehicles are much quieter than those that use conventional internal combustion engines.
9. No Visual Pollution
Some low-carbon energy sources, including wind energy and biofuel power plants can be an eyesore, however, hydrogen fuel cells do not have the same space requirements, meaning that there is less visual pollution too.
10. Long Usage Times
Hydrogen fuel cells offer greater efficiencies with regard to usage times. A hydrogen vehicle has the same range as those that use fossil fuels (around 300 miles). This is superior to that currently offered by electric vehicles (EVs), which are increasingly being developed with fuel cell power units as ‘range-extenders’. Hydrogen fuel cells are also not significantly impacted by the outside temperature and do not deteriorate in cold weather, unlike EVs. This advantage is increased further when coupled with the short charging times.
11. Ideal for Use in Remote Areas
Where local conditions allow, the availability of hydrogen through local generation and storage could prove to be an alternative to diesel-based power and heating in remote areas. Not only will this reduce the need to transport fuels but will also improve the lives of those living in distant regions by offering a non-polluting fuel obtain from a readily-available natural resource.
12. Versatility of Use
As the technology advances, hydrogen fuel cells will be able to provide energy for a range stationary and mobile applications. Hydrogen powered vehicles are just one example, but it could also be used in smaller applications such as domestic products as well as larger scale heating systems. Similar to ICE powerplants, the functions of energy storage capacity (ie. the fuel tank) and engine size are decoupled, in contrast to battery-based power (ie. for which power scales linearly with mass), thus providing great flexibility in design.
13. Democratisation of Power Supply
Hydrogen fuel cells have the potential to reduce the dependency of a nation on fossil fuels, which will help democratise energy and power supplies around the world. This increased independence will prove a benefit for many countries who are currently reliant on fossil fuel supply. Of course, this will also avoid the problem of rising fossil fuel prices as stocks reduce.
Hydrogen Power Case Studies
TWI has a great deal of experience and expertise in the power generation sector and you can find out more about this here.