Why hydrogen could be the future of green energy

From the way we power and heat our homes to the fuel we use in our vehicles, the energy sources on which we depend release harmful carbon dioxide into the atmosphere.

Given the scale of the decarbonisation challenge, we need to use many technological solutions in tandem. But one element has so far been forgotten: hydrogen.

Our demand for energy keeps growing. Analysts forecast our energy demand in 2050 will be 30-40% higher than today, even assuming we become much more energy-efficient. Increases on this scale are not unprecedented. Over the past 30 years, worldwide energy demand has more than doubled. What is unprecedented is the transformation needed in how we generate that energy.

Renewables are getting cheaper, and have received more than $2 trillion of investment globally in the past decade. Yet the share of our energy obtained from fossil fuels has hardly budged. Since 1980, renewables have increased from less than 1% of the primary energy mix to just over 1% today. In contrast, fossil fuels have remained at a stubborn 81% of the primary energy mix.

We need to scale up existing low-carbon technologies at a much faster rate – otherwise population growth will continue to outpace investment in renewables, and fossil fuels will continue to dominate. We cannot, however, keep asking for more from technologies that have proved successful to-date.

The International Energy Agency (IEA) highlights that only three of twenty-six low carbon innovation areas - solar PV and onshore wind, energy storage and electric vehicles (EV) - are mature, commercially competitive and on track to deliver their share of the climate objectives set out at the 2015 Paris Climate Conference.

It is unlikely we can squeeze more out of these three technology areas than is currently projected. Solar PV and onshore wind are intermittent, so need to be used in conjunction with energy storage or other forms of power generation. The high-energy-density batteries that are used for both storage and EVs are causing concern around whether the supply of raw materials needed to manufacture them will be able to keep pace with their rapid uptake. According to BNEF, graphite demand is predicted to skyrocket from just 13,000 tons a year in 2015 to 852,000 tons in 2030, and the production of lithium, cobalt and manganese will increase more than 100-fold. This is already creating pressure on supply chains and prices - and on the people working in these mines, often in incredibly poor conditions.

So what other options are available to us? The World Economic Forum’s latest white paper proposes some bold ideas to significantly accelerate sustainable energy innovation and support the uptake of future energy sources. One energy vector mentioned there that is often forgotten is hydrogen.

Hydrogen has the potential to decarbonise electricity generation, transport and heat. That’s because when produced by electrolysis - using electricity to split water (H2O) into hydrogen and oxygen - hydrogen does not produce any pollutants.

Perhaps the best-known use for hydrogen currently is in transportation. With electric vehicles, drivers are often concerned about their range and the time it takes to recharge. Fuel cell electric vehicles, which run on hydrogen, avoid these concerns, as they have a longer range, a much faster refuelling time and require few behavioural changes.

Hydrogen can also be used to heat our homes. It can be blended with natural gas or burned on its own. The existing gas infrastructure could be used to transport it, which would avoid the grid costs associated with greater electrification of heat.

Once produced, hydrogen could also act as both a short and long‐term energy store. Proponents suggest that surplus renewable power – produced, for example, when the wind blows at night – can be harnessed and the hydrogen produced using this electricity can be stored in salt caverns or high-pressure tanks. Earlier this month a report by the Institution of Mechanical Engineers called for more demonstration sites and a forum in which to discuss hydrogen’s long-term storage potential.

Hydrogen clearly has several potential uses, but more research, particularly in production and safety, is needed before we can use it at scale.

Currently, almost all of global hydrogen (96%) is produced by reforming methane (CH4), a process which ultimately produces carbon dioxide. To be sustainable, this production method would need to be deployed with carbon capture and storage, which is itself in need of further development.

Electrolysis produces no carbon emissions. Yet the amount of hydrogen that can be produced using this method depends on the cost and availability of electricity from renewable sources. A report by the Royal Society suggests that electrolysis may be better suited for vehicle refuelling and off-grid deployment rather than for large-scale, centralised hydrogen production.

Concerns about the safety of using hydrogen also need to be addressed. A report by the UK’s National Physical Laboratory noted two priority safety issues when transporting hydrogen in the grid and combusting it for heat. When hydrogen is combusted, you can’t see the flame, so there needs to be a way of detecting whether it is lit. Hydrogen would be transported and stored at high pressures, so we need to find an odorant that works with hydrogen so that people can detect leaks.

The appetite to explore hydrogen as an energy vector is growing at pace, but reports need to be followed up with action.

The research challenges that hydrogen poses are not unique to one country or company, so collaboration in developing and trialling technologies will be critical. Both businesses and governments seem to recognise this. Last year the Hydrogen Council, a group of multinational companies with a ‘with a united vision and ambition for hydrogen to foster the energy transition’, was launched at the World Economic Forum in Davos. And earlier this year governments have also agreed to collaborate on the topic, launching a new theme under the Mission Innovation partnership focussed on bringing hydrogen technologies closer to market.

Hydrogen is not the panacea - but then neither is solar PV, offshore wind or battery storage. We need several varied technologies if we are to decarbonise successfully. Hydrogen looks very likely to be one of them.

Our new report, Accelerating Sustainable Energy Innovation, is available here.