Using hydrogen in home heating has shown promising results in greening up the gas grid. About 85% of UK homes use natural gas in home heating and contribute to a third of the UK's greenhouse gas emissions.
Hydrogen is readily available in the natural world and can play a similar role to natural gas. The main attraction to the gas is the ability to use it similarly to natural gas. For instance, you will continue to use gas boilers to heat your home. Hydrogen is also cost-effective since it can run through the same pipe network that has been useful for heating homes for centuries with small modifications.
Let's look at how hydrogen gas is a viable option for home heating and its drawbacks.
A hydrogen boiler is similar to natural gas boilers, but instead of burning methane, it burns hydrogen to heat water. The hot water is either supplied through the taps or radiators to warm your home or stored for later use. Hydrogen fuel cells do not rely on combustion to generate heat. Instead, they rely on chemical reactions that produce both heat and electricity. Using hydrogen fuel cells can warm your home and power the devices in your home.
While both hydrogen boilers and fuel cells are promising steps towards reducing natural gas emissions, they require replacing the boilers and other infrastructure. Hydrogen is a thinner gas than natural gas, and the parts of a hydrogen boiler, like the flame detector and the burner, will be different.
The introduction of hydrogen-ready boilers for central heating is a more cost-effective solution for eliminating carbon. Hydrogen-ready boilers can burn both methane and hydrogen. That means, when the gas network switches to methane, homeowners won’t have to replace gas boilers. In hydrogen-ready boilers, hydrogen mixes with other gases before being ignited to burn in a catalytic burner. Methane flames are visible, so the boiler will not need a flame detection component, but hydrogen-only boilers need it since the flames are invisible. After heating the gases, they flow through the heat exchanger pipes heating the surrounding cold water used in the heating system and taps.
The premise of using hydrogen is due to its harmless by-products. For example, during heating, the only by-product in hydrogen boilers is water. However, the method of producing hydrogen will determine the amount of carbon emission. For instance, the electrochemical process of separating hydrogen from fuel sources could lead to carbon emissions. But using electrolysis to separate water molecules produces carbon-free hydrogen. The only downside is the cost of electrolysis.
The benefits of hydrogen in home heating
The main selling points for hydrogen as an alternative fuel are its high energy content and green credentials. The low carbon emission can decarbonise our homes and contribute to the zero greenhouse gas commitment by 2050. Converting the entire gas system from methane to hydrogen can cut the domestic carbon emission by 73%.
Hydrogen also packs a lot of energy, making it an energy-efficient source of fuel. For instance, one kilogram of hydrogen contains equal amounts of energy as 2.8 kilograms of gasoline. That means it can produce sufficient heat to warm your home and power some devices.
Shifting from natural gas to hydrogen will cause little interruption to the current infrastructure and consumers. The heat supply will not change, and you don’t have to change your radiators or heating system. While there will be a process of converting to hydrogen-ready boilers, you will only change a few parts of the boiler instead of buying a new one. You may also have to check the adequacy of the existing pipes since hydrogen is prone to leakage and it is flammable.
Hydrogen is easy to store, making it an efficient power source. Some of the long-term storage techniques for hydrogen include compression and liquefying the gas. However, some hydrogen suppliers use salt caverns and ammonia to store the gas. That means, in the future, you can use it for cooking and store it in gas cylinders.
Obstacles of hydrogen heating
While hydrogen provides numerous eco-friendly benefits, it comes with a few challenges that may slow down its adoption in home heating. The main criticism comes from its production process. Green hydrogen requires a lot of electricity to produce while splitting fossil fuel into hydrogen causes carbon emission. Luckily, using renewable energy to produce electricity lowers the cost of electrolysis. Besides, researchers have come up with a method of capturing and storing carbon emissions resulting from hydrogen production.
Hydrogen is a highly flammable gas, and leakages can cause explosions. The safety concerns are reducing the rate of adoption of the technology. Therefore, further research and assessment are necessary to evaluate the safety measures required to use hydrogen in home heating.
Hydrogen heating may not be viable in some residential properties, and you may have to install a new heating system before using hydrogen. Besides, 100% hydrogen may be hazardous to use on current appliances designed to use natural gas. Therefore, it may be necessary to replace the radiators and other appliances to accommodate the use of hydrogen. Some homes will also require better insulation to improve energy efficiency.
Despite the obstacles related to using hydrogen, it shows remarkable strides in reducing carbon emissions from residential homes. Moreover, its adoption for central heating will be cost-effective in the long run since it is a renewable energy source.