The writer chairs the Policy Institute at King’s College London
The last decade has seen dramatic growth of more than 16 per cent a year in the global consumption of electricity from renewable sources such as solar and wind.
The reduction in costs — down 70 per cent for wind and 89 per cent for solar over the past decade — opens the prospect of further significant growth over the next decade. That will help reduce emissions and encourage the replacement of emission-intensive sources of electricity.
But wind and solar are not going to solve the challenge of climate change, because the majority of energy use cannot be switched to electricity. Other solutions are necessary.
The favourite option for now seems to be hydrogen, which could help oust hydrocarbons (oil, coal and natural gas) in areas that are beyond the reach of electrification, such as the heating sector or the production of iron and steel. How far away is such a possibility, and what are the barriers?
We are at the end of Act One in the story of renewables. The sector is no longer dependent on subsidies and can now produce at scale as the latest plants being developed in countries such as the US and China demonstrate. The largest solar facility in the world — the Tengger Desert plant in China — has a capacity of more than 1,500MW and supplies 600,000 homes.
Act Two will see the industrialisation over the next decade of both wind and solar and their penetration of markets across the world. According to the International Energy Agency, some 15 per cent of total final energy consumptionis likely to come from these two sources by 2030 and falling costs should encourage more electrification, not least in vehicles.
That is all to the good, but Dolf Gielen and Emanuele Taibi of the intergovernmental International Renewable Energy Agency say that is not sufficient. Even if half of all final consumption was electrified, the other half — including heavy lorries, much of the heating sector and energy intensive industries such as iron and steel — remains overwhelmingly dependent on fossil fuels.
To go further we have to move beyond the first-generation renewables — wind and solar.
One much-promoted solution is the use of hydrogen, which could be produced either from non-renewable energy sources such as natural gas, with the carbon captured and stored — “blue” hydrogen — or from electrolysis of renewables, and then used as a direct power source or converted into other fuels such as ammonia or synthetic hydrocarbons — “green” hydrogen. Technically, both are practical possibilities.
Hydrogen has some clear advantages that could make it a serious part of the energy market. It can be transported relatively easily, for instance in pipelines, and could therefore use existing natural gas transport systems. It can be stored, adding to energy security and avoiding the challenges of intermittency.
And since green hydrogen can be produced by using power generated by wind and solar, a good deal of which is likely to be surplus to immediate needs, it could be generated at low cost and in effect provide a means of storing renewable energy.
Hydrogen is not a new fuel — it powered the first internal combustion engines two centuries ago, and was integral to Nasa’s space programme. Some 70m tonnes of pure hydrogen are used each year worldwide, but at the cost of 830m tonnes of carbon dioxide emissions.
But making it commercially competitive and, crucially, to reduce emissions requires a combination of factors. Those include a continuing fall in the cost of renewables to power the electrolysis process to deliver green hydrogen and/or a radical reduction in the costs of carbon capture and storage to make blue hydrogen viable.
A significant increase in the total volume of production is needed to deliver economies of scale as well as the mass manufacturing of the equipment involved, such as fuel cells and electrolysers.
In addition, there is more potential in producing hydrogen from fossil fuels — blue hydrogen — in ways that minimise greenhouse gas emissions.
None of this is impossible, as the record of first-generation renewables shows, but exploiting the potential of hydrogen requires large-scale projects, backed by public policy decisions.
As things stand, there are many small-scale developments but none sufficient to cut unit costs enough or to resolve the technical challenges involved in using hydrogen in specific markets such as home heating.
The issue is a classic example of the need for public/private co-operation. Governments can set the regulatory framework and support research but private investment is needed to deliver major projects and make hydrogen a viable alternative fuel.
The development of first-generation renewables was spurred by public policy interventions by Germany and later the UK, and much of what has happened since was triggered by those steps. Hydrogen now needs comparable interventions. Without them, its potential will remain unfulfilled.
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