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Why hydrogen could be the future of green energy

Why hydrogen could be the future of green energy

Monday 23rd November 2020

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.

Hydrogen can be considered as the simplest element in existence. Hydrogen is also one of the most abundant elements in the earth’s crust. However, hydrogen as a gas is not found naturally on Earth and must be manufactured. This is because hydrogen gas is lighter than air and rises into the atmosphere as a result. Natural hydrogen is always associated with other elements in a compound form such as water, coal and petroleum.

Hydrogen has the highest energy content of any common fuel by weight. On the other hand, hydrogen has the lowest energy content by volume. It is the lightest element, and it is a gas at normal temperature and pressure

At the request of the government of Japan under its G20 presidency, the International Energy Agency produced this landmark report to analyse the current state of play for hydrogen and to offer guidance on its future development

The report finds that clean hydrogen is currently enjoying unprecedented political and business momentum, with the number of policies and projects around the world expanding rapidly. It concludes that now is the time to scale up technologies and bring down costs to allow hydrogen to become widely used. The pragmatic and actionable recommendations to governments and industry that are provided will make it possible to take full advantage of this increasing momentum.

Hydrogen and energy have a long shared history – powering the first internal combustion engines over 200 years ago to becoming an integral part of the modern refining industry. It is light, storable, energy-dense, and produces no direct emissions of pollutants or greenhouse gases. But for hydrogen to make a significant contribution to clean energy transitions, it needs to be adopted in sectors where it is almost completely absent, such as transport, buildings and power generation.

The Future of Hydrogen provides an extensive and independent survey of hydrogen that lays out where things stand now; how hydrogen can help to achieve a clean, secure and affordable energy future; and how we can go about realising its potential.

Supplying hydrogen to industrial users is now a major business around the world. Demand for hydrogen, which has grown more than threefold since 1975, continues to rise – almost entirely supplied from fossil fuels, with 6% of global natural gas and 2% of global coal going to hydrogen production.

As a consequence, production of hydrogen is responsible for CO2 emissions of around 830 million tonnes of carbon dioxide per year, equivalent to the CO2 emissions of the United Kingdom and Indonesia combined.

We can electrolyze the hydrogen whenever we have excess sun or wind. As Liebreich predicts, we will then store it in massive underground caverns near the central nodes of our power grids, where it can be fired up at short notice during lulls in direct electricity generation. Hydrogen is thus the plug-in technology to make the overall project of electrification and decarbonization possible.

Multiple types of businesses could benefit from such power-to-gas systems, Reichelstein says. “A utility could use a system like this,” he says. “So could a firm with large demand for hydrogen.

Utilities could take advantage of the intermittency of renewables by earning a premium on the generated electricity through the conversion to hydrogen when power demand is low but wind and sunshine are strong. Chemicals manufacturers such as BASF or DuPont, on the other hand, could either procure hydrogen from the market or produce it themselves through their own renewable power sources, he points out.

Reichelstein is confident that the power-to-gas systems examined in their model will be widely competitive for large-scale hydrogen production in the near term — three to five years. But he notes caveats. Germany, for instance, offers significant subsidies for renewable power, and it’s not certain whether a company there would still qualify for those if it’s converting such power to hydrogen instead of feeding it into the grid. “You have to keep the regulatory environment in mind,” Reichelstein says.

The applications go well beyond merely replacing fossil fuels to produce the hydrogen used today. “The next generation is things like using hydrogen for transportation,” Reichelstein says, “or converting hydrogen back to power at certain times of day when power is scarce.”

Of course, Reichelstein notes, the fossil fuel industry will continue to defend the energy status quo: “People who are not concerned about carbon emissions will say, ‘Why first produce hydrogen from power, then use hydrogen as a transportation fuel? It’s complicated and expensive compared to just taking crude oil from the ground.’”

Moreover, even if climate change is a key consideration, there are alternatives to hydrogen-based energy-storage systems. “Someone like Elon Musk thinks it’s inefficient to use electric power to make hydrogen for transportation and instead supports storing the energy in batteries,” Reichelstein says. “But energy efficiency is not the ultimate criterion for the marketplace.”

Reichelstein thinks of the research as “a stepping-stone” to show that using renewable energy to make hydrogen through electrolysis is at least competitive with current hydrogen-production systems. He also points out that the prices of renewable energy and electrolyzers continue to drop, which is likely to position hydrogen as an even more competitive fuel source.

“It’s currently very much up for grabs,” he says. “We’ll know more soon.”

 

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