The UK is actively considering the variety of roles hydrogen could play in helping to meet net zero carbon emissions, and other countries are doing the same.
A new standardization document, PAS 4444, is supporting hydrogen’s potential expansion, and is aimed at giving guidance to appliance developers and manufacturers. Household names Bosch and Baxi are already developing boilers to work with hydrogen gas.
So it’s likely we’ll be hearing a lot more about hydrogen as a fuel for the future.
What are the goals?
Under the Paris Agreement of 2015, 195 countries committed to act to reduce global warming [1]. To date, 5 have introduced legally binding net-zero emissions targets. In June 2017 Sweden committed to becoming carbon neutral by 2045; and the UK, France, Denmark and New Zealand are aiming for net-zero by 2050 and passed legislation in 2019.
Each of these countries have chosen different approaches to reach their targets. Sweden has invested in nuclear and hydroelectricity; Denmark in wind generation; and France in nuclear, with a growing interest in hydrogen. New Zealand is already producing 80 per cent of its electricity from renewables. But the biggest challenge is dealing with methane – a gas about 28 times more powerful than carbon dioxide at warming the Earth [2]. Methane makes up a third of New Zealand’s total emissions and is a result of the country’s large herd of farmed sheep and cattle [3].
The UK is also pursuing a range of measures. Investment has gone into off-shore wind farms [4] and the UK is investigating how its dependence on natural gas from the North Sea can be curtailed. Around 30 per cent of the UK’s emissions are from natural gas used to heat houses, with 85 per cent of homes relying on gas-fired central heating. This has led the UK Government to set up the Hy4Heat Research and Innovation Programme to explore whether it’s feasible to replace methane with hydrogen for heating and cooking.
Hydrogen’s advantages
The big advantage of hydrogen is that it doesn’t release carbon dioxide during combustion. The only waste product it produces when burned is water. It’s conceivable that hydrogen could replace natural gas in domestic gas appliances without significant upheaval for consumers. They could simply transition to a dual-fuel / hybrid boiler as their old boiler needs replacing.
That said, hydrogen doesn’t exist in a pure form on Earth, so has to be processed one way or another – a cost that makes hydrogen relatively expensive for the time being. It can be extracted by passing an electric current through water (H2O), a process called electrolysis. If the electricity is generated using renewable energy from wind, solar or tidal sources, the resulting “green” hydrogen is entirely emissions free. Hydrogen is also readily found in natural gas. But this extraction process generates CO2 as a by-product, meaning that carbon capture technology needs to be deployed to make the process emissions free.
Countries leading the way
Significant hydrogen generation projects are already underway in Australia, Canada, France, Germany, South Korea and California. Germany has introduced the world’s first hydrogen powered trains. China has already nearly 100 hydrogen fuelling stations for around 5,000 fuel-cell vehicles. Norway is investigating its vast potential for extracting green hydrogen from hydropower. Japan’s “Hydrogen Society” vision was to be showcased at the 2020 Olympics, spear-headed by Toyota’s development of the world’s first commercial hydrogen-powered fuel cell car.
The UK story
There are many examples such as Scotland is working on the first hydrogen powered seagoing ferries to connect the Orkney Isles, while England has unveiled a zero-emissions, hydrogen-fuelled double-decker buses for London [5].
In a pioneering trial of hydrogen in a modern gas network, Keele University is blending 20 per cent hydrogen with its natural gas supply on its Stoke-on-Trent campus and the result makes no difference to heating or cooking performance. If a 20 per cent blend could be rolled out across the UK, it would reduce CO2 emissions by six million tonnes – equivalent to taking 2.5 million cars off the road.
To take hydrogen’s use further, the UK Government’s Hy4Heat programme is a study to establish if it’s technically possible, safe and convenient to used it in residential and commercial buildings and gas appliances. To support this, BSI have released PAS 4444:2020 Hydrogen fired gas appliances – Guide.
Guidance for gas appliances
PAS 4444 supplies guidance on developing and building hydrogen-fired gas appliances that are either purpose-built to use hydrogen or are designed to be converted to use hydrogen. It covers the functional specification of the appliance, including specific advice on demonstrating safety and including worst-case conditions to stress the appliance in excess of that it is likely to experience in normal service.
The PAS could form the basis of wide-scale hydrogen fuel appliance standardization in the UK and beyond. Its use will help to progress the exploration of hydrogen’s role as a major contributor to curbing climate change.
