The much heralded hydrogen economy has never materialised but within niche applications the future is looking bright for this clean energy technology.
It is more than 40 years since Professor John Bockris coined the phrase 'the hydrogen economy' in a lecture at GM's Technical Centre in Dearborn and, despite several false dawns, that age of hydrogen seems as far away today as it did all those years ago.
We still live in an age of hydrocarbons, with cars and other vehicles running primarily on petroleum and power generation relying on fossil fuels. The proponents of hydrogen argue that it can be an environmentally cleaner source of energy to end-users, particularly in transportation applications, without release of pollutants or carbon dioxide at the point of end use.
"I think it went through a bit of a hype in the early 1990s and some disappointments in the middle, but in the last couple of years I have seen a turnaround and now the discussions and the position of the industry seems to be a lot more real across a whole bunch of the sectors," Richard Kemp-Harper, Lead Technologist, Transport and Energy at the Technology Strategy Board (TSB) says. "In the automotive industry, the major OEMs are saying that they will bring hydrogen-fuelled cars to market in 2014/2015.
"There are also countries with hydrogen infrastructure making very positive noises - Germany, Japan, Korea. So it is a positive story and, on the technology side, the performance is there, with the fuel cells."
When it comes to fuel cells there are still barriers, particularly about cost and how they are manufacturing them in volume, but that is the stage that we are at now. "The technology is performing at the level needed for some of the new markets," Kemp-Harper says. "It's a very different story than you would have found in the UK a couple of years ago. It seems to be a reality setting in and the discussions are moving forward very positively between the different players."
Hydrogen has a high-energy density by weight. An Otto cycle internal-combustion engine running on hydrogen is said to have a maximum efficiency of about 38 per cent, some 8 per cent better than a petrol engine.
The combination of the fuel cell and electric motor is two to three times more efficient than an internal-combustion engine. However, the high capital costs of fuel cells are one of the major obstacles of its development. Other technical obstacles include hydrogen storage issues and the purity requirement of hydrogen used in fuel.
Despite the opportunities that are emerging for the use of hydrogen, people are still cautious of talking about economy. "There are solutions and opportunities behind hydrogen in different places and I think there has been a realisation that you can actually use hydrogen in a number of areas," Kemp-Harper adds. "There is not one of them that is going to drive the whole market, but you need to use it in different places and see how they hang together."
That sits very nicely with a project that the TSB have just announced examining what role hydrogen plays in the energy system. "You can use hydrogen to store renewable power when you don't need it and then you can use it when you do need it: but also you can use it as a transport fuel," Kemp-Harper adds. "So we are saying what is the opportunity of hydrogen in the energy system and how can we use that hydrogen to solve transport problems in decarbonised transport."
Five major government-backed research and development projects will speed-up the adoption of energy systems using hydrogen and fuel cell technologies, bringing them into everyday use. Funded by the TSB and the Department of Energy and Climate Change (DECC), the projects will demonstrate the use of fuel cell systems and hydrogen technologies in low-carbon energy systems and transport. The plan is to demonstrate how these technologies can be integrated with other energy and transport components, such as renewable energy generation, refuelling infrastructure and vehicles, to develop whole systems and show them working together.
"All of the projects that we have got in that suite have got links to renewable energy and wind power or solar energy into hydrogen and then using that hydrogen in transport uses as well as other uses," says Kemp-Harper. "That's exploring hydrogen at what we call whole system level."
For the automotive sector the primary challenge is the cost of the fuel cells. "We've got the system performing - there are early markets opening up, but if you're looking towards automotive, you've got to bring the cost down and you've got to manufacturer at volume," Kemp-Harper admits. "If you are talking about hundreds of thousands of vehicles by 2020, which is what the vehicle manufacturers are, that's several orders of scale up on our current manufacturing capability. So we need to be looking at those technologies now to be able to deliver that to market on the timescale of the automotive manufacturers.
"It might seem like a long-term barrier but we need to be looking at that now. In November we are probably going to be launching a competition on addressing that issue for the industry."
Aside from the cost and manufacturing challenges for fuel cells another obstacle that must be overcome before hydrogen can enter the mainstream transport sector is storage. At the moment, manufacturers are looking at compressed gas at a 700bar standard. "That's a high pressure scenario," Kemp-Harper says. "There are technological challenges around managing hydrogen at that pressure. There are also technologies that could come in and help reduce that pressure. So there is a lot around solid state hydrogen storage and some quite interesting technologies starting to emerge that could drastically reduce the pressure and increase the storage of the hydrogen and do things in different ways."
The ultimate goal for vehicular transport will be electric vehicles driven by hydrogen fuel cells. But today these are new, unproven and expensive technologies. Alternatively, it is possible to convert a conventional internal combustion engine (ICE) to run on hydrogen, with minimal engine modifications. This H2-ICE route offers quick, low-cost and low-risk access to low-carbon motoring for a fraction of the cost of developing fuel cell or lithium-ion battery-powered vehicles.
"This is a brand new way of storing hydrogen that has been developed over the past four years with a team led by Professor Stephen Bennington," Bryan Sanderson, chairman of Cella Energy explains. "When most people think about hydrogen they think about compressed hydrogen gas and that is highly explosive. We are not using hydrogen gas at all; we are using chemically absorbed hydrogen so you end up with a very safe, low-cost fuel. We have developed a way to produce liquid fuels that can be handled more safely than gasoline or diesel while being used in a similar way; they can be put in the car by a regular petrol pump allowing it to travel the same sort of distance you would expect.
"The breakthrough comes from using materials called complex hydrides, which in their natural form are very difficult to handle. What we do is take those materials and encapsulate them using nano-structuring techniques, making tiny beads that are 30 times smaller than a grain of sand. They are encapsulated in an outer layer that means we can handle them safely in the open air. The result is a fuel which would behave like a fluid that we could pour and use in a vehicle in a way that people are familiar with."
Another area for hydrogen that has been moving higher up the agenda in recent years is energy storage and how hydrogen can play a part. The opinion is that the electrolyser technology is about the level when you could start talking about doing it seriously.
"The thing that is important is that you have to look at things on the whole energy system level," Kemp-Harper says. "We are looking at what might be called smart energy technologies to bring intelligence into the distribution network. So that is smart meters at the home, but also intelligence on the networks and technologies like hydrogen electrolysers in the system as well as other storage technologies. To put the whole system together so you can make the system work as a whole and reduce costs because you don't have to upgrade the whole network, but you just manage it a lot better."
The hydrogen landscape is going to be fraught with activity over the next three or four years as the vehicle manufacturers are committed to bringing hydrogen-powered vehicles to market by 2014/2015. This has set European governments into a planning frenzy looking at what the infrastructure requirement to support this emerging market. "There is going to be a lot of activity and investment in that area with industry and the government working together," Kemp-Harper says. "That is going to create a lot of impetus and I think alongside that we are going to have the exploration of hydrogen in the energy system.
"The department of energy and climate change are supporting us in our programme and have put some co-funding into that, so there is a strong policy interest as well in how that works and how that will support the other things that are going on in energy. Over the next few years you will see a better evidence base for the way this is going to move forwardit's going to move away from being speculative to be being based on evidence and where the markets are actually developing."