By Professor Anthony Kucernak – Chief Scientific Officer @ Bramble Energy Ltd.
There has been a fundamental conundrum surrounding the introduction of fuel cells for the last twenty years or so. Fuel cells operate best using hydrogen as a fuel, but without large numbers of deployed fuel cells utilising hydrogen, no distribution network will form. With no hydrogen distribution network, fuel cells can only ever be a niche player in the energy system.
In the early and late seventies a series of oil shocks led to oil prices initially tripling and ultimately reaching six times their value before the oil crisis. This instability led to a resurgence of interest in renewable energy and what was termed the “Hydrogen economy”. In fact the concept of using hydrogen as a “systems fuel”, that is as a vector for energy distribution, had existed for some time previously, and even Jules Verne had one of his protagonists proclaim the virtue of hydrogen as a fuel in his story “The mysterious island”. But guess what happened at the end of seventies? The cost of oil dropped, and the impetus to transition to a cleaner and more stable fuel infrastructure went away. Today, we still enjoy prices of hydrocarbons far below the peak of the late 70’s (in inflation adjusted terms), although there continues to be instability in its price. It is clear that we will see fluctuations of oil price in the future, and the cost will inexorably rise. Are we at the time when hydrogen finally comes to supplant hydrocarbons as an energy vector? I think so.
In the period following the oil crisis a number of things have happened: the first is the continuous exponential drop in costs of renewables as solar photovoltaics (following Swanson’s law) or from wind farms (showing a similar continuing drop in cost); the next is the rise of more stringent emissions requirements as the number of people killed by pollution becomes better understood. Finally, there is the desire of the 195 countries that have signed the Paris accord to reduce their CO2 emissions. For most countries in the world, this means that increasing amounts of energy will be generated by renewables (take a look at Electric Insights for a realtime look at what the UK electricity grid is doing). That’s great in terms of sustainability, but causes problem for the distribution networks due to the intermittency of those resources.
If we had a way to store that excess energy and deal with periods when there is no sunlight and/or no wind, then we could increase the proportion of renewable energy (and not have to rely on nuclear energy to prove a CO2 free baseload). It would be especially nice to be able to store energy in the summer so that we can use it in the winter, like the ant in Aesop’s fable. Batteries will certainly go some of the way, but they are, and will continue to be, too expensive to store seasonally produced energy. That’s where hydrogen steps in.
Arguments have been put forward in the past that hydrogen is always the “second best” option (viewed from this perspective, our currently used hydrocarbons are also second or even third best): electricity (and hence batteries) are better at powering portable equipment; as a long term energy storage medium, pumped hydroelectric offers better round trip efficiency, and lower cost; as a heating fuel, natural gas is an easier way of providing heat. But these arguments neglect the fact that when viewed from a systems perspective, hydrogen can solve many problems simultaneously. That was the conclusion of the UK’s Hydrogen and Fuel Cell Supergen network in their 2017 whitepaper: “The role of Hydrogen and Fuel Cells in Future Energy Systems”, in which it is shown that the least-cost pathway for the UK to meet its CO2 reduction objectives relies on a significant proportion of hydrogen production (about 100 TWh p.a.).
Hydrogen makes sense as a systems fuel – that is hydrogen functions in a similar way to hydrocarbons in that it can be used for a wide range of different things. It might not be the best solution to any given problem, but the fact that it answers so many problems, means that it represents an optimum energy vector. Here is a list of things that hydrogen can do:
Act as a heating and cooking fuel. Northern Gas Networks have shown that converting the city of Leeds from using natural gas to methane is both practical, and can be achieved at a reasonable cost (H21 Leeds Citygate report). Indeed, they point out that for the first 200 years of operation, the UK gas network utilised mostly hydrogen (town gas), and it is only in the last fifty years that the network has operated using natural gas. Maybe it’s time to switch back to hydrogen?;
Replace coke in making steel. Currently the steelmaking industry is responsible for more than 5% of global CO2 emissions (OECD). Utilising hydrogen instead of coke would significantly reduce the CO2 emissions provided it is produced in a CO2 free process (i.e. using hydrogen produced through electrolysis using carbon free electricity or utilising CO2 sequestration);
As a precursor to ammonia to produce fertilisers. Did you know that 30% of the nitrogen in your body was made by taking atmospheric nitrogen and reacting it with hydrogen to produce ammonia? The production of nitrogen fertilisers from ammonia through the Haber Bosch process has prevented a billion people from starving.
As a future precursor to hydrocarbons. One day when all the liquid hydrocarbons are gone, we will need to still make hydrocarbons for use in plastics and pharmaceuticals. Those hydrocarbons will come from CO2 or biomass and hydrogen.
What does that mean for our energy system? It means that hydrogen is here to stay and that it will grow in importance in our energy system. With the growth in hydrogen comes the ability to finally put to bed the “chicken and egg” problem mentioned at the beginning of this piece. The ubiquity of hydrogen means that fuel cells will proliferate, and the greater importance of fuel cells in the energy generation system will increase the penetration of hydrogen as future fuel.