Hydrogen: Abundant Possibilities

14/06/2013 12:52 BST | Updated 13/08/2013 10:12 BST

The global energy mix is evolving rapidly and there are now several alternative energy sources that can supplement or replace fossil fuels. Among these, hydrogen is gaining popularity as a fuel for transport in conjunction with fuel cell electric vehicles, although the person in the street is relatively unfamiliar with it.

Hydrogen however, has the potential to be much more than a transport fuel. It is abundantly available - whether directly manufactured or as a waste by-product from the chemical and other industries. Hydrogen also provides a useful means for storing renewable energy from intermittent sources - for example, when the grid demand for wind or solar electricity is low. Moreover, hydrogen can also be used as a heating fuel in our homes and offices, blended with natural gas.

In fact, this little known fact of its ability to blend with natural gas means that hydrogen can be put into the national gas supply network itself, producing a blended gas with less concentration of carbon and thus reduced carbon emissions when burnt.

Hydrogen is already manufactured and consumed on a huge scale by industry across the globe, with over 50 million tons produced word-wide every year - that's enough to fill the tanks of 14 million family cars! Today most hydrogen comes from the reformation or cracking of natural gas, but hydrogen is also routinely manufactured by electrolysis, using electrical current to split water into hydrogen and oxygen; this process is in fact the reversal of the reaction that occurs in fuel cells.

So here is an abundant fuel, with zero emissions that the world is going to make much greater use of.

For the EU to meet its 80% decarbonisation target by 2050, carbon emissions from road transport will need to be reduced by about 95%. On top of climate change concerns, the effect of transportation emissions on human health is beyond debate. It has been estimated that air pollution contributes to 3,000 premature deaths every year in London alone.

Cars powered by hydrogen fuel cells are considered one of the best options for ultra-low carbon transportation. Fuel cells combine hydrogen gas with oxygen from the air to produce electricity and pure water as the only emission.

Fuel cells, like batteries, are highly efficient, with 2-3 times the efficiency of a typical internal combustion engine. However, unlike batteries, hydrogen fuel cells do not require extended periods of recharging after use and can continue to produce power for as long as they are fuelled. Fuel cell electric vehicles (FCEVs), which use hydrogen to power an on-board electric motor, do not have the range limitations or anxiety of shorter range battery-only powered vehicles - and they can be rapidly refilled with hydrogen (even more quickly than with petrol/diesel).

The value of hydrogen also lies in its ability to enable electricity to be stored in bulk. Unlike oil and gas, which are routinely kept as strategic reserves, electricity will generally go to waste unless used immediately.

One of the main issues with an increased role for renewable energy is the intermittent nature of renewable technologies. Renewable electricity from wind can be zero, or at other times it can exceed what the grid can handle. Hydrogen offers a solution. In times of excess wind, surplus electricity can be converted, via electrolysis, into hydrogen. The hydrogen can then be stored to be used in times of wind deficit to generate electricity back into the power grid, or to be injected into the gas grid.

Hydrogen produced by the power generating companies offer flexibility in another way also. It is predicted that by 2030 there will be 1.6 million fuel cell cars on the roads in Britain, all fuelled by hydrogen, and by 2050 a quarter of the cars on the road could be FCEVs. Hydrogen, therefore, offers the power generating companies the opportunity to enter the transportation fuel market to make a significant contribution to the decarbonisation of road transport and to meet carbon emission reduction targets.