Why hydrogen?
What is it that makes hydrogen so ideally suited for a role in a sustainable energy supply system? This is the question we address at length in the following, as we explain why we are still going to need ‘molecules’ in the future and why the hydrogen molecule can help us make our energy supply sustainable, and secure the reliability and affordability of our energy system.
Hydrogen, a key element of a sustainable energy supply
In the following, we zoom in on the various roles that carbon-neutral hydrogen could play in a sustainable energy supply system. On the one hand, we focus on how the hydrogen molecule can be used in moving various market segments towards sustainability: the molecule role. And on the other hand, our focus is on hydrogen's role in system integration, i.e. the role hydrogen can play to keep our energy system affordable and reliable.
The use of hydrogen in market segments, the molecule role
This long read also goes into how hydrogen can be used in various market segments in great detail. To summarise, hydrogen has the potential to play a key role in moving the following four market segments towards sustainability, which basically boils down to decarbonising segments where electrification is either not a viable alternative or not possible at all.
- Hydrogen as a raw material The (petro)chemical industry needs molecules as a raw material for its processes, meaning that their products cannot be made using electricity. At present, the raw material they use is generally hydrogen from oil or gas, but this is relatively easy to replace with sustainable hydrogen.
- Hydrogen for high-temperature processes Some industrial processes are hard, or even impossible, to turn into sustainable processes through electrification, especially processes that involve extremely high temperatures. This can be put down to various reasons, including the substantial outlay involved in electrification, the fact that the technology has simply not been invented yet, or the basic reason that the electrical equipment is not resistant to the high temperatures. With hydrogen, however, reaching these high temperatures ceases to be a stumbling block.
- Hydrogen for heavy and long-haul transport Various means of transport, such as heavy goods vehicles, commercial shipping or (large) aircraft simply cannot be electrified due to technical reasons. Here, too, hydrogen can provide a solution, directly as a fuel or as a base material for synthetic fuels.
- Hydrogen for heating Full electrification of heating in the built environment requires a delicate balance of substantial insulation, heating system efficiency and network capacity. The use of molecules would lower transport costs and guarantee sufficient heating supply, thus simplifying the move towards sustainability for the built environment. This can also involve a combination of electrical and gas systems, known as hybrid systems. Although green gas initially seems to be the obvious molecule to use for this, hydrogen can be used in combination with a condensing boiler or fuel cell technology in the long term.
The importance of molecules
Currently, over 80% of the Netherlands’ total energy consumption (industry including raw materials, built environment, mobility and agriculture) comes from gaseous, liquid and solid sources of energy: molecules. These molecules, in turn, mainly come from natural gas, oil and coal. These forms of energy contain carbon that, upon combustion, is released in the form of CO₂, i.e. precisely the kind of emissions we want to reduce.
Just under 20% of our total energy need is met using electrons, better known as electricity. Roughly 15% of all electricity used in the Netherlands is generated from sustainable sources. For most of our electricity production (85%), however, we still depend on fossil fuel power stations.
The general expectation is that electricity’s share in the Netherlands’ final consumption will double to roughly 40% by 2050, which will enable us to make our energy supply more sustainable. After all, we can use heat pumps, electric cars and certain industrial processes to switch from fossil molecules to electricity. Needless to say, this electricity will then have to be generated from sustainable sources. The supply of sustainable power will consequently have to rise in step with growing demand for electricity.
The main conclusion to draw from all this is that we are still going to need molecule-based energy to meet the remaining 60% of our energy need in 2050. Given our target of a carbon-neutral energy supply system, we are going to need sustainable molecules for this (or carbon capture when using fossil energy sources). Geothermics, biomass or carbon-neutral hydrogen can provide us with these carbon-neutral molecules.
The hydrogen molecule
Various sustainable molecules will feature in our sustainable energy supply system. Each of these molecules comes with specific upsides and downsides. Hot water (residual heat and geothermics), for example, will increasingly be used to heat buildings. Residual heat generally comes from gas-fired and coal-fired power stations, which have no place in a sustainable energy supply system. Geothermics has great potential, but is still in its infancy. And then there is biomass, which can be used as a raw material in the chemical industry, for combustion processes, to make green gas or hydrogen, to produce biofuels, or in other applications. But biomass is scarce, and should be used only when there are no other alternatives.
There are currently certainly also downsides to carbon-neutral hydrogen. It is, for example, still too expensive to make, there is limited availability, and national infrastructure is lacking. That said, hard work is currently going into eliminating these downsides, as we will explain later in this long read.
To sum up, our sustainable energy supply will be made up of different forms of energy. The Institute for Sustainable Process Technology’s HyChain report details the potential role of carbon-neutral hydrogen in different market segments compared to the potential role of geothermics and biomass.
The use of hydrogen for the energy system: the system role
Besides the role that carbon-neutral hydrogen plays in sustainability implementation in market segments that are difficult or even impossible to move towards sustainability using other forms of energy, hydrogen also plays a role when sustainable electricity falls short. This is hydrogen’s system role, i.e. the role an energy carrier can fulfil in guaranteeing the reliability and affordability of the entire energy system.
From a societal perspective, hydrogen has the potential to fulfil this important system role. Hydrogen makes it possible to link the electricity system to a sustainable gas system, which we often refer to as system integration. Integrating the systems comes with the huge benefit that one system’s strong features can balance the other system’s weak features.
Milk and cheese, electricity and hydrogen
The hydrogen expert at Japanese car maker Toyota, Professor Katsuhiko Hirose, explains the value of hydrogen using an analogy with milk and cheese. Milk is the electricity, of which you sometimes have too much. When you use that excess milk to make cheese (which stands for hydrogen in this analogy), you have a derived product with a longer shelf life. In fact, this in itself can also be a reason to make cheese out of milk. Is that wasting milk? No, you are using the milk to make a new product, one that does not compete with milk, but with other, more expensive products.
Dunkelflaute
Hydrogen has the potential to be instrumental in system integration on different levels. A video published by Greenpeace clearly explains the importance of hydrogen for system integration, providing further details on the various subjects covered in the text below. This video is about the periods of shortfall, with a special focus on the ‘Dunkelflaute’ phenomenon, i.e. periods during which there is not enough sunshine and wind to generate solar and wind power, and how this correlates with import constraints in such situations, the role of battery storage for short periods of time, and the role of hydrogen for long-term storage to ensure sufficient availability of hydrogen-generated sustainable electricity during such periods of shortfall.
In the following, we explain why carbon-neutral hydrogen will have to play an important role in keeping our energy system reliable and affordable. What it boils down to is this:
- Hydrogen enables large-scale and long-term energy storage
- Hydrogen enables cost-effective energy transport and distribution
- Hydrogen enables large-scale, efficient integration of renewable energy
1. Hydrogen enables large-scale and long-term energy storage
The supply of sustainable electricity generated from solar and wind energy does not automatically adapt to demand like a conventional gas-fired or coal-fired power plant does. Over the summer months, renewable electricity generated often exceeds demand, while it is unable to keep up with demand over the winter months. The ideal would be to use the surplus from the summer months to also ensure a reliable energy supply in winter, which would involve storing large volumes of electricity over a long period of time in a practice that is referred to as buffering.
This is where hydrogen comes in, as it makes it possible to store generated electricity for use at another time. The excess electricity can be converted into hydrogen, and this hydrogen can subsequently be used to generate electricity again, as and when necessary. Until you need that electricity, you can store the hydrogen on a large scale and for as long as you want. Although converting electricity into hydrogen, and hydrogen back into electricity, does incur energy losses, not using this option at all would mean that excess electricity would simply be lost and that electricity would have to be generated from other sources to cover periods of shortfall.
In addition to the ‘regular’ covering of seasonal supply-demand mismatches, hydrogen can in the same way also play a role in covering energy supply shortfalls over periods of only a few days and/or weeks of extremely low solar and wind production and high demand for sustainable electricity. In Germany, such periods are already a well-known phenomenon, for which they have even come up with a new word, ‘Dunkelflaute’, which loosely translates as ‘dark doldrums’. A ‘Dunkelflaute’ is a very real scenario. Over a period of 10 days in 2017, there was hardly any solar and wind energy supply in Germany.
Hydrogen is set to be instrumental in balancing supply and demand in our electricity system by, among other things, storing seasonal excess supply and covering long periods of shortfalls. Hydrogen will thus help create a reliable energy system.
Hydrogen can be stored on a large scale in salt caverns. The figure below quantifies hydrogen storage in terms of time and capacity, comparing it to other forms of energy storage.
Comparison of energy storage methods
Buffer capacity for sustainable energy supply
To get a sense of the magnitude, the following will go into the total volume of energy that would have to be buffered in a fully sustainable energy supply system in the Netherlands to be able to overcome supply-demand mismatches in summer and winter. Buffering for international aviation and shipping has not been included in this projection. Hydrogen will, alongside other molecules, be able to meet part of this buffering need.
The projection of how much energy would have to be buffered in a fully sustainable energy supply system in the Netherlands is based on data from a study entitled ‘Net voor de Toekomst’ (‘Grid of the Future’). When we extrapolate the various scenarios presented in this study to energy buffering, we get very similar pictures with respect to energy buffering needs in each scenario.
The example below uses the Regional scenario. In this scenario, energy consumption has been reduced significantly, our society has largely gone electric, and the share of renewable generation has increased considerably to 84GW of solar power and 42GW of wind power.
Summary of assumptions for ‘Net voor de Toekomst’ (‘Grid of the Future’) study scenarios Source: Netbeheer Nederland. Click the figure to enlarge.
To be able to establish the extent of the need for buffering, we first have to compare energy supply (the blue line in the figure below) and energy demand (the orange line). The yellow bars represent the energy surplus or shortfall on a monthly basis.
Analysis of monthly energy shortfall or surplus in a sustainable energy supply system in the Netherlands, Regionalscenario from the ‘Net voor de Toekomst’ (‘Grid of the Future’) study Gasunie, based on Netbeheer Nederland, ‘Net voor de Toekomst’ (‘Grid of the Future’) study
The above graph clearly shows that there is generally a shortage of sustainable energy over the winter months and a surplus over the summer months, despite the assumed 60GW of battery storage capacity in the Netherlands. These batteries in the form of home batteries and car batteries make sure consumers have the right amount of power available at the right time, but they are not suited for long-term seasonal storage (buffering). This scenario also includes demand-side response options as short-term flexible resources. Aside from that, the analysis of how much sustainable electricity could be imported shows that importing electricity generated from solar and wind power from neighbouring countries is not a reliable and, therefore, not a viable option. After all, weather conditions in the countries around us are generally the same as here.
We therefore need reserves we can dip into over the winter months and replenish over the summer months. The exact extent of these reserves (i.e. the buffer) can be calculated by adding up the consecutive shortfalls, the cumulative shortfalls shown as brown bars in the graph below.
The buffer capacity, as depicted by the green bars, has to absorb these cumulative shortfalls. As you can tell by the height of each green bar, the buffer diminishes over the October-March period, and is replenished over the April-September period. To prevent a shortfall in March, the buffer needs to be the size indicated by the green bars.
Analysis of monthly energy buffer needs in a sustainable energy supply system in the Netherlands. Regional scenario from the ‘Net voor de Toekomst’ (‘Grid of the Future’) study. Gasunie, based on Netbeheer Nederland, ‘Net voor de Toekomst’ (‘Grid of the Future’) study
2. Hydrogen enables cost-effective energy transport and distribution
The Infrastructure Outlook shows that, as we continue to make our energy supply more sustainable, the electricity transmission network will reach its limits after 2030.
The power grid will be expanded significantly over the coming period to be able to meet growing demand for electricity. But even this expanded power grid will not be able to accommodate the (necessary) rapidly growing volumes of electricity generated from solar and wind energy in the long term.
A large part of this excess supply will have to be stored in the form of hydrogen. To be able to make our energy supply fully sustainable, we are, therefore, going to need a hydrogen network.
Following on from that, it may in certain cases also be cost effective or even a pure necessity to, instead of transporting electricity generated by offshore wind turbines to the shore using cables, turn the electricity into hydrogen first and then transport it to shore through a pipeline. After all, laying submarine power cables is roughly twice or three times as expensive as laying pipelines.
Per-kilometre costs of transport
Both the cost-effectiveness of energy transport through a pipeline and efficient use of scarce public space are arguments in favour of building hydrogen infrastructure, for which we can reuse parts of the existing natural gas infrastructure.
3. Hydrogen enables large-scale, efficient integration of renewable energy
Large-scale electricity generation from solar and wind energy will regularly result in excess electricity supply and increasingly create situations where the power grid cannot handle the volume of electricity supplied to it (grid congestions).
Hydrogen makes it possible to make the most of the huge potential supply of solar and wind energy, which may otherwise have to be interrupted. The electricity generated from that vast potential of solar and wind energy can be converted into hydrogen through a process called electrolysis. This can even be done immediately inside/near the wind turbine or solar panel, which would mean efficiency gains in comparison to ‘regular’ electrolysis.
Sunshine and wind only generate electricity when the sun shines and the wind blows. The resulting input instability leads to price fluctuations. Conversion into hydrogen can, as it were, pave the way for a price floor for electricity, and help electricity prices stabilise somewhat. Conversion into hydrogen is, therefore, a solution to the increasing risk (from a producer’s perspective) of prices of sustainable electricity falling as demand continues to grow. Converting electricity into hydrogen thus offers wind turbine operators a financially attractive additional business case, potentially prompting more entrepreneurs to set up wind farms.
As soon as it becomes necessary, hydrogen can be deployed in the various market segments in its molecule role, or it can be converted back into electricity (with energy losses, depending on the type of power station used). Hydrogen is an important source for a reliable, sustainable electricity supply. While it is not very efficient, it is still one of the few options available for a sustainable power station where capacity can be ramped up and interrupted rapidly.
The role of hydrogen in system integration – various reports
The various possible roles of hydrogen have been detailed in a range of international reports, including one by the Hydrogen Council. For the Netherlands specifically, two reports are highly relevant.
‘Net voor de Toekomst’ (Grid of the Future) study, Netbeheer Nederland
Commissioned by the joint Dutch power and natural gas network operators, Netbeheer Nederland, the sector organisation for network operators, conducted a study of what the future may hold for the Netherlands’ energy system, publishing their findings in a report entitled ‘Net voor de Toekomst’ (‘Grid of the Future’) (in Dutch).
In this study, Netbeheer Nederland developed four scenarios for a sustainable energy supply in the Netherlands in 2050, assessing the potential of electrification and whether home batteries, smart control and import could cover supply shortfalls.
2050 Infrastructure Outlook, TenneT and Gasunie
Netbeheer Nederland’s study was the basis for a joint study by TenneT and Gasunie, the 2050 Infrastructure Outlook, the first joint capacity analysis by the Netherlands’ two national network operators for electricity and gas. The conclusion they draw in this study is that existing electricity and gas infrastructure in the Netherlands and Germany will have to continue to play a crucial role in achieving the targets from the Paris Agreement on climate change, and that a hydrogen infrastructure is needed.
Besides sustainable methane (which can be transported using the existing gas network), additional sustainable molecules in the form of hydrogen will be needed whenever electrons are insufficiently available. Part of the Netherlands’ gas infrastructure will have to be repurposed for the transportation of hydrogen.
