Hydrogen is likely to play a vital role in our domestic and commercial energy mix as we transition towards a low carbon economy. If you receive our newsletter, you will know that governments around the round are beginning to call time on gas-powered heating systems to meet their strenuous net-zero commitments.
Energy from hydrogen has several likable characteristics as a renewable energy source, and in this article, we will unpack these characteristics. We will also talk about some of the blockers to large-scale adoption of the technology, learning lessons from trial projects worldwide.
Problems with existing energy solutions
Firstly we need to clarify why governments are even contemplating shifting from their existing energy sources for space heating & cooling (typically gas).
We are currently in the middle of a climate crisis, and the burning of gas gives off greenhouse gases which make this crisis worse. Space heating accounts for around 17% of the UK's total carbon footprint, of which approximately 13-14% is domestic heating, and 3-4% is commercial.
Following the UK Government's recent decision to ban natural gas boilers from 2025, alternatives must be sought, and it's likely that by 2025, hydrogen-ready boilers will be the natural switch. But you don't necessarily have to wait until 2025; hydrogen-ready boilers are available today, which can run on a mix of hydrogen and natural gas until the level of hydrogen can be increased (more on this later).
What is a Hydrogen Boiler? A like-for-like replacement?
The hydrogen boiler is very similar in composition and usage to a natural gas boiler; we burn the hydrogen to heat water for house heating.
The exciting part about hydrogen is that we can extract it from several different sources through different methods. Different methods all have different benefits, disadvantages, and levels of energy efficiency, which I will briefly explain below. Without wanting to get too technical, I feel it is important to learn a little about each of the different methods of hydrogen extraction and relate this to how it could be used in homes or the built environment more generally.
What about hydrogen fuel cell boilers?
If the hydrogen gas is not piped into a house or commercial property, it is possible to generate the hydrogen onsite using a hydrogen fuel cell boiler. This creates renewable electricity that can be used throughout your home to heat hot water and a boiler.
A leading example of this type of boiler is the Viessmann Vitovalor: a Micro CHP (combined heat and power) system. This will cost you at least £10,000, up to £15,000 including installation.
Methods of hydrogen extraction
Extraction by heat and chemical (thermochemical reaction)
As the name suggests, heat and chemical reactions are used to extract hydrogen from fossil fuels, biomass, or even water. Natural gas reforming is currently the most commonly used form of hydrogen as it's reasonably reliable, and byproducts of existing fossil fuel-based processed can be used.
This method is also sometimes referred to as 'blue' hydrogen - the (important) disadvantages which will be discussed below. Also in this category is methane gas to hydrogen conversion, using a similar process.
Hydrogen extraction by electrolysis
This idea is being actively researched currently and concerns the process of using electricity to split water into hydrogen and oxygen.
Photolytic extraction of hydrogen
Photolytic extraction involves the use of solar energy to split water into hydrogen and oxygen. There is long-term potential for sustainable hydrogen production with a low environmental impact using this method, but researchers are still working on scaling the technology.
Bacteria and algae are also viable sources of hydrogen and are typically extracted via a fermentation process. Microorganisms such as bacteria break down organic material to produce hydrogen.
Today, hydrogen fuel can be produced through several methods. The most common methods today are natural gas reforming (a thermal process), and electrolysis. Other methods include solar-driven and biological processes.
If you're interested in learning more about the different way we can extract hydrogen - this video gives a good overview:
Benefits of hydrogen heating
Now that we are familiar with some of the ways in which hydrogen can be extracted from source fuels. We can look at the advantages that come with this process:
- No need to replace infrastructure - the current 'strategy' being researched by many developed nations in Europe is to generate hydrogen on an industrial scale and then hydrogen to hydrogen-ready boilers in homes using the existing gas network. From a logistics point of view, this is a big benefit as it will require no extra installation work (especially when compared to the ground source heat pump.
- Kinder on the environment than natural gas - when hydrogen is burned, the byproduct is water, this is a huge positive when compared to the combustion process of a gas boiler
- Hydrogen can be stored and transported relatively easily - This gives it flexibility as an energy source; it can either be generated at the point of use, nearby or piped in via the old gas networks.
- Familiar user experience - the hydrogen boilers are very similar on the outside to a typical gas boiler.
Disadvantages of hydrogen energy solutions (current blockers to adoption)
If hydrogen is such a great alternative energy source, why aren't we using it to heat our homes? In fact, why do we still have gas heating? Well, it turns out that there are a few issues that have to be worked out before hydrogen can be used for this purpose:
- Blue hydrogen (or natural gas reforming) methods of hydrogen production will still leave us reliant on fossil fuels. Therefore, critics argue that this is not a sustainable solution and, if anything, encourages fossil fuel companies to continue burning fossil fuels.
- Other methods of extraction currently suffer from an efficiency problem as they are still experimental. There are still efficiency gaps to be found before the technology can be rolled out at scale, some believe.
The National Grid Hydrogen Project
Despite some of the challenges involved in scaling hydrogen gas production, National Grid in the UK is investing over 1 billion GBP in a 'backbone' network which will involve the repurposing of 25% of the existing gas network.
This could cater for at least 25% of the existing gas demand, diversifying and adding resilience to the country's energy mix. You can read more about this project here.
Gateshead Hydrogen Housing Trials
To get an understanding of the role of hydrogen in our future homes, a team in Gateshead, UK, has developed a pilot project of hydrogen houses (powered 100% by hydrogen technology).
FAQs for Hydrogen Fuel Cells
What is a hydrogen boiler? Hydrogen is a low-carbon alternative to natural gas that could be delivered to properties through the existing gas network. The key difference is that it could not only heat the home with natural gas but hydrogen too (it will likely be a mix of the two during a transition period).
What is a hydrogen fuel cell? A hydrogen fuel cell breaks down hydrogen into its different parts to generate electricity.
Can I buy a hydrogen boiler? Yes, commercial hydrogen boilers are available. Hydrogen-ready boilers accept a hydrogen/gas mix, where hydrogen fuel cell boilers generate electricity on-site (although more expensive).
What are the hydrogen-ready boilers? While they might not be available to buy yet, some boiler manufacturers have been developing prototypes of hydrogen-ready boilers.
How much will a hydrogen-ready boiler cost? You can expect to pay between 1000GBP and 4000GBP for the boiler and installation fees. Combined heat and power
What is the UK government's plan to reduce greenhouse gas emissions? Specifically, the UK government has passed into law that, as a nation, our carbon emissions will be at net-zero by 2050.
What Is a Hydrogen-Ready Boiler? A hydrogen-ready boiler is a gas-ﬁred heating boiler that is capable of burning either natural gas or pure (100%) hydrogen.
What are the environmental benefits of hydrogen? Hydrogen is a carbon-free energy carrier, and hydrogen combustion produces no carbon dioxide at the point of use. However, sometimes through the natural gas reforming method and other thermal reaction-based hydrogen extraction methods, fossil fuels are still required.
What are the benefits of hydrogen-ready heating systems? Hydrogen-ready boilers offer flexibility and a certain element of future-proofing for homeowners. Hydrogen-ready boilers can be powered by a hydrogen blend (normally 80% natural gas, 20% hydrogen). Hydrogen networks also make use of the existing infrastructure, engineers and their price point will improve over time.
What are the UK's hydrogen projects? National Grid Hydrogen Project: From next year, Fife, Scotland will become the first location in the UK where hydrogen appliances will be trialed in over 100 homes and fed with hydrogen gas directly from the grid.