In one of the latest offerings from Abundance, the crowd-funding platform, Northern Gas Networks (NGN) is seeking to raise £1m from individual investors to help fund a very small part of its programme of making the pipeline network ready for a transition away from natural gas to hydrogen. NGN says that this fund-raising is part of its programme to involve the UK public in its plans for moving towards zero carbon emissions.

Why is hydrogen so important?

Green hydrogen will provide a boost to decarbonisation efforts. It has two principal roles

1. To allow countries around the world to switch to 100% renewable sources for their electricity. The key issue facing wind and solar power is the intermittency and unreliability of electricity generation. We won’t always have power when we need it.

Green hydrogen made from water electrolysis solves this problem. When electricity supply is over-abundant, the surplus is used for making hydrogen, which is then stored. And when power is in short supply, hydrogen can be extracted from storage and then burnt in conventional gas power stations to provide an immediate boost to electricity generation. In this way, it is a near-perfect complement to ever-cheapening renewables.

2. Separately, hydrogen can also replace fossil fuels in those activities that cannot be switched to electricity. For example, steel-making currently uses about 20% of world coal and is responsible for perhaps 8% of world greenhouse gases. Coal can be entirely replaced by hydrogen. And green hydrogen stored in the form of ammonia will provide the fuel for long-distance shipping. Some heating needs may shift from natural gas to hydrogen, including those of domestic homes.

These two areas of use will allow green hydrogen to grow rapidly over the next decades. It will become a central pillar of our move to ‘net zero’.

How will green hydrogen be transported?

Some hydrogen will be used close to where it is produced. For example, the Spanish utility Iberdrola is developing a large PV farm next to a fertiliser factory.[1] The solar electricity will be used to make hydrogen, a critical ingredient for fertiliser production. Another big scheme in Germany envisages hydrogen made from offshore wind used in a new steel plant near the port of Wilhelmshaven.[2]

Alongside local use of hydrogen, developers are also planning huge pipeline networks. One proposed scheme sees a total of 40,000 km of pipeline criss-crossing Europe by 2040.[3] About two thirds of this grid will use existing natural gas pipelines, repurposed to carry hydrogen. This will provide much of the capacity to move the gas from where it is made to the place of utilisation. So, for example, hydrogen will be made at offshore wind farms, at the base of the turbines or on dedicated platforms, and then carried by pipe to large industrial centres where the gas will be used.

This shouldn’t surprise us: it is far cheaper to transport hydrogen over long distances than it is to shift electricity. One estimate is that the cost could be as low as about 0.3 Euro cents per kilowatt hour for a 1000 km link.[4] That’s roughly the distance from Penzance to Aberdeen. The cost of building a new pylon link to move electricity over this distance would be much greater. And it would be almost impossible to get the political support to allow a new above-ground electricity link, as policy-makers in countries such as Germany have found when they have proposed new north-south power networks.

But is it safe to move hydrogen around in pipelines? Doesn’t the gas corrode the pipes, resulting in eventual leakage? No, hydrogen can probably be moved with greater safety than methane, or natural gas. Pipelines cannot be made from iron or steel which is embrittled by hydrogen, but thick plastics are effective and safe. The world already has several large pipeline systems for hydrogen, including at least 1,600 miles of pipe in the US, without any serious reported problems.[5]

At normal pressure, hydrogen is a much less dense substance than methane, the primary ingredient in natural gas. So it will be need to be transported at higher pressure. This means that pipelines being converted from natural gas to hydrogen will need to add compressors along the trunks and branches of the networks.

How will the hydrogen be stored?

Of course we will also need substantial storage to enable hydrogen to match the supply and demand for energy. The UK is lucky in that large parts of the country have thick layers of salt well underneath the surface. Hydrogen can be stored by dissolving some of this salt in water and then extracting the brine. This creates what are called salt caverns, which usually have the approximate shape of a wine bottle, sometimes hundreds of metres in height. The remaining salt is almost totally impermeable to hydrogen. In fact, three salt caverns have been used for hydrogen storage in the UK for several decades and more can be found in the US. Salt caverns also already provide large storage capacity for natural gas in various parts of the world, including China.

To summarise; a switch to an energy economy that combines renewable and green hydrogen is the most likely route to net zero, in the UK and elsewhere. Large fractions of our solar and wind farms will need to be devoted to making hydrogen, at least part of the time. And this hydrogen will need to be transported to the end-user. This looks both technically possible and highly economical. Many of the users will be large industrial companies.

Hydrogen in the home

Many UK homes will switch to heating with electricity, principally using what are known as ‘heat pumps’. But hydrogen can also be used a fuel for heating buildings and in many circumstances this may be cheaper for the homeowner and equally compatible with the UK’s zero carbon objectives. This will replace natural gas, which creates CO2 when burnt. On the other hand, hydrogen just turns into water vapour. We’ll need new central heating boilers but these are likely to be no more expensive than today’s natural gas equivalents. And much, but not all, of the UK’s gas pipeline network still needs to be modified to carry hydrogen to homes, schools, offices and other buildings.

This is where the Abundance debenture issue for Northern Gas Networks (NGN) comes in. NGN wants to have pipelines, small and large, that can safely and effectively accommodate a possible switch to hydrogen from natural gas. This is a costly programme, but we cannot continue to burn fossil fuels in homes and other buildings and hydrogen is the obvious replacement for some of our homes and other buildings.

[1] https://www.iberdrola.com/press-room/news/detail/iberdrola-fertiberia-launch-largest-plant-producing-green-hydrogen-industrial-europe

[2] https://www.uniper.energy/news/uniper-plans-to-make-wilhelmshaven-a-hub-for-climate-friendly-hydrogen

[3] https://gasforclimate2050.eu/news-item/european-hydrogen-backbone-grows-to-40000-km/

[4] https://gasforclimate2050.eu/news-item/european-hydrogen-backbone-grows-to-40000-km/

[5] https://www.energy.gov/eere/fuelcells/hydrogen-pipelines