Hydrogen Economy

Given the problems associated with renewables it's perhaps no wonder that nuclear power has started to look more attractive. There is another option though. An efficient alternative fuel source exists that can power both our homes and our cars, and without producing any greenhouse emissions whatsoever. What's more, this fuel could even be used to overcome the problems of intermittency facing renewables. That solution is hydrogen.

Hydrogen-powered fuel cells are battery-like devices that use electrochemical reactants to generate electricity. The difference is that with a fuel cell the reactants need to be periodically replenished, just as vehicles need to be topped up with fuel to keep them going. Although there are a number of different types of fuel cell, the cleanest takes hydrogen as its fuel and combines it with oxygen from the air to generate electricity, producing only steam as a waste product.

Many analysts have predicted that when oil reserves do eventually dry up, our oil-based global economy will be replaced by a hydrogen economy. Indeed, most car manufacturers are now in the advanced stages of developing hydrogen cars. And mains electricity is predicted to come from either domestic or industrial hydrogen fuel cell plants, spewing out nothing more than water.

But if it all sounds too good to be true, it is. The fact is more than 95% of hydrogen currently comes from fossil fuels. And although the rest comes from a very renewable resource, water, it is obtained through electrolysis – a process that uses electricity to separate water into oxygen and hydrogen. While this might sound pretty clean, remember that this electricity was produced by burning fossil fuels. So while hydrogen may be clean to use it is still far from clean to produce.

However, this is where renewables re-enter the scene – wind, solar and wave power could be used to produce hydrogen through electrolysis, which could then be stored in hydrogen-powered fuel cells. This is an effective way of converting the energy from renewables into a form that can be stored.

Critics point out that hydrogen can be more dangerous and difficult to store and distribute than other fuels, such as petrol. But supporters argue that hydrogen merely lends itself to a more localised form of energy distribution – instead of having huge centralised power plants the hydrogen could be produced locally and would have less distance to travel before it was used. In Iceland, a fleet of hydrogen-fuelled buses fill up at a hydrogen station. The station receives only mains electricity and water as an input and produces hydrogen by electrolysis. This electricity input could come from a renewable energy source.