Hydrogen gas as an alternative to natural gas; is it that easy?

The Netherlands has set itself some ambitious climate objectives. By 2030, we want to emit 49% less CO2 and by 2050, even as far as 95% less. A fast and affordable transition to sustainable energy depends entirely on how clean energy will be distributed. How easy is that?

Now for how we store it and distribute it to users

Sustainable energy is being generated in more and more places. Solar panels are now a common sight on our streets. New wind parks are being developed in the North Sea. New-build homes are often delivered gasless and already meet their own energy demand to a certain extent. Users unable to meet their own energy demand will become reliant on the supply of sustainable energy. Consider the somewhat older homes, for example, but also industry, which requires a great deal of energy. We know how to generate sustainable energy; now we just need to work out how to store it and distribute it to users. That is the main technical problem within energy transition.

Batteries: a dubious alternative?

Sustainable solar and wind energy can be transferred to users via the electricity grid. Following considerable improvements to the electricity grid, many batteries were required in which to store the energy. But batteries have a limited capacity and limited lifespan, are harmful to the environment and therefore require an effective recycling programme. Mining raw materials for these batteries, such as cobalt and lithium, also uses a great deal of energy. What’s more, a lot of cobalt comes from third world countries in which mining doesn’t really take people and the environment into account. Whereas batteries still seem to be a controversial alternative for energy storage, hydrogen has the better credentials as an energy carrier.

No CO2 emissions in the combustion of hydrogen gas

Groningen natural gas consists of several gases: 82% methane, 14% nitrogen and a number of other gases, even including carbon dioxide. The energy carrier in natural gas is methane and has the chemical formula CH4. Methane consists of one carbon atom and four hydrogen atoms. For normal combustion, the residual products are H2O (water vapour) and CO2 (carbon dioxide). Hydrogen gas (H2) consists of two hydrogen atoms. In the case of the combustion of hydrogen gas under normal conditions, the residual product is 100% H2O (water vapour), which means that no CO2 is produced! That makes hydrogen the energy-carrying alternative to natural gas. The only difference is we have to produce it ourselves.

Hydrogen gas from natural gas or water

Hydrogen gas doesn’t occur naturally. It is so light that it rises immediately to the uppermost regions of the earth’s atmosphere. Hydrogen gas is therefore something that we have to produce ourselves. There are two ways of doing this.

Blue hydrogen

This is extracted by “cracking” natural gas, producing hydrogen and carbon dioxide as the by-products. The clean hydrogen is used as a fuel and the carbon dioxide is stored in controlled conditions in former gas fields.

Green hydrogen

By sending an electric current through water, the water is broken up into oxygen and hydrogen. This is known as electrolysis. The clean hydrogen is used as a fuel and the oxygen is released into the atmosphere in a controlled manner.

Green hydrogen is called “green” because the electric power required for electrolysis is generated from sustainable sources such as wind energy and solar energy.

Hydrogen through the existing natural gas network

It’s true that hydrogen gas has different properties to natural gas. It is very light, lighter than helium, and therefore used to be used in air ships and hot air balloons. Yet according to KIWA, our natural gas network is suitable for transporting hydrogen gas. According to experts, it is necessary to replace parts, including weak parts such as seals and alterations to compressors. According to experts, the costs are between 200 and 300 million euros. That is 2% of the estimated value of our entire natural gas network. It will soon be possible to distribute hydrogen through the existing, altered natural gas network to users throughout the country.

Adding hydrogen to the mix

Gas appliances that are currently being used by companies and consumers will need to be replaced. According to experts, converting appliances for the 100% combustion of hydrogen simply isn’t feasible. However, up to 20% hydrogen can be added to natural gas without a problem, as already proven by extensive tests on households on the island of Ameland. Yet over time, it will be necessary to replace all existing gas appliances, For example by developing hybrid appliances that are able to switch between natural gas and hydrogen.

Hydrogen supply for cold, overcast and windless days

Just like other fossil fuels, natural gas is located underground in large fields, so that constitutes the majority of our supply straight away. Underground salt domes, such as those found in the north of the Netherlands, are also used as buffers for periods when the demand is greater – a sort of grab stock.

On a cold, overcast and windless winter’s day, little sustainable energy can be obtained from the wind and sun, but the demand is great. On the flip side, more sustainable energy can be produced on a sunny and windy day than there is demand for it. Energy, in the form of hydrogen gas, should also be stored in a buffer stock in order to meet the changing demand.

Liquefying for storage

There are different methods for storing hydrogen gas. One method that has already been tried and tested is underground storage in gas form in former empty natural gas fields and salt domes. With above-ground storage, space is the determining factor. By liquefying hydrogen gas, you can store much of the gas in tanks. You can liquefy a gas by compressing it (350–700 bar) or cooling it to a minimum of -253 °C.

Three times as much hydrogen gas required than natural gas

Due to its properties, 3 m3 of hydrogen gas supplies just as much energy as 1 m3 of natural gas, during combustion. In the future, three times as much hydrogen gas will therefore need to flow through the natural gas network in order to meet the same energy demand as is currently the case with natural gas. That means that the buffer stocks also need to be three times greater than is currently the case with natural gas

1 litre of petrol supplies just as much energy as 4 litres of liquid hydrogen

Despite the fact that hydrogen can be turned into a liquid, additional storage is required. The same also applies to vehicles that use hydrogen as a source of fuel. Special tanks are required which need to be thermally insulated in order for the hydrogen to remain liquid. The tanks are also getting bigger in order to maintain the same operating range. After all, 1 litre of petrol supplies just as much energy as 4 litres of liquid hydrogen. So now you have a 40-litre tank of petrol, and soon you will need a 160-litre tank to achieve the same range.

Opportunity to innovate

The transition to hydrogen is easier said than done. There are still a lot of things that need to be figured out and sorted out – and not just from a technical perspective, but an organisational one too. The core of the technical problems lies in efficient and safe production, storage and distribution. That is a great opportunity to innovate. And innovation is good for the economy and for the Netherlands in particular, with its powerful knowledge economy.

“Delta plan for hydrogen”

An all-encompassing plan and a project schedule are necessary in order to begin the transition to hydrogen on time. Experts speak of a “Hydrogen Delta Plan”, looking back at the 1960s. At that time, the Netherlands made the transition from coal and city gas to natural gas. That all went pretty smoothly, despite the fact that thousands of kilometres of pipeline had to be laid and all kinds of gas appliances in households replaced or converted.

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