Converting large parts of the UK gas grid to use zero-carbon hydrogen is suggested to be both technically and economically viable and would help the country meet its greenhouse gas emission targets.
This is according to a report published by the H21 Leeds City Gate project which proposes to convert Leeds-the UK's third largest city with a population of 760,000-first. The city will be converted from natural gas to hydrogen gas by 2030, before converting other sections of the UK network.
Reducing UK’s heating emissions
Currently, cooking and heating generate over 30% of the UK's carbon emissions. But the conversion of the grid to hydrogen gas can reduce heat emissions by at least 73% In addition, it will also support decarbonisation of transport and local electricity generation.
While the process of combusting hydrogen with oxygen - which produces no carbon emissions, just water and heat - to power vehicles is well known, the opportunity to use the same process on the grid for domestic heating and cooking has not really been looked into.
But, according to Dan Sadler, H21 Project Manager at Northern Gas Networks - the gas distributor for North East England involved in drawing up the proposals - a nationwide grid conversion to hydrogen gas "is technically possible, economically viable and will be a significant contributor to meeting the UK's decarbonisation targets".
"This is a major opportunity for our country to become a world leader in hydrogen technology and decarbonisation and would create thousands of new jobs across the UK," he said.
Moreover, H21 claims that the hydrogen gas grid can use the existing underground gas pipes and that converting household appliances to run on hydrogen would mean less disruption and unnecessary costs when compared to converting to alternative green heat sources.
Sadler says that the conversion process will be similar to that carried out in the 1960s and 70s when 40 million appliances across 14 million households were converted from town gas to natural gas. “We'd have special teams, working street by street to make the conversion as smooth as possible for customers with minimal impact in the homes and the highways."
Iron Mains Replacement Programme
According to H21, the UK has been undertaking the 'Iron Mains Replacement Programme' (IMRP) since 2002 to upgrade the majority of gas distribution pipes to polyethylene - a material for transmitting hydrogen.
Work on the IMRP will be completed by 2032, and as such conversion of the network to use hydrogen would require minimal new energy infrastructure and limited disruption to customers. Additionally, the gas network has the appropriate capacity for such a conversion.
The report points out that there are already a small number of models on the market for household appliances which run on hydrogen, while "several manufacturers are showing real enthusiasm for their development".
"A firm, long-term plan and significant stimulus would be needed to provide the motivation to develop and produce the wide range of equipment required," the report states. "This could potentially be in the form of a national heat policy."
Leeds-first city to be converted
Leeds has been identified as the most suitable area to start the network conversion both due to its significant energy demand and its geographical location, and the proposals have received backing from Leeds City Council as well as Leeds City Region and Tees Valley Unlimited local enterprise partnerships.
Initial conversion in Leeds, the report estimates, could save up to 1.5 million tonnes per year of CO2.
"Transforming Leeds into a hydrogen city would be a bold step," said Leeds city councillor and executive member for the environment, Lucinda Yeadon. "It could play a crucial role in how we heat and power our homes in the future alongside other sustainable energy sources.
"The project has massive potential to make a significant dent in the city's environmental performance, as well as opening up a wealth of opportunities for innovation, manufacturing and low carbon transport. Working closely with Northern Gas Networks and our partners, we're keen to develop this exciting concept further."
A key question is the source of the hydrogen for such a large scale initiative. Further, hydrogen is not the only option for decarbonising heat and others are heat networks powered by low carbon heat sources and high efficiency heat pumps. [Decarbonising homes-the UK challenge] As this article suggests a mix of these are likely to result with one or other solution being more appropriate for a given area or region.