New techniques that could offer fresh approaches to net zero were a key topic of conversation at IMechE Focus: Power and Energy earlier this month (1-5 June). The webinar week explored emerging power generation technologies and focused on the engineering approaches needed for a resilient low-carbon future.
Here are some of the most important messages from three of the sessions in the webinar series.
Data centres offer hot new opportunity
Current government policy incorrectly prioritises electricity generation over heating and transport, said Professor Ian Arbon, founding member and past chair of IMechE’s Energy, Environment and Sustainability Group. Heat energy represents the largest portion of UK energy demand but has received the lowest policy priority, he said, noting that less than 3% of homes are connected to heat networks and fewer than 1% have heat pumps installed.
“If we had acted more responsibly over the years, and found better, more sustainable ways of heating ourselves… the current angst over the closure of the Strait of Hormuz would be unnecessary, and we would not be even considering the opening up of new oil and gas fields in the North Sea to further exacerbate the climate problem,” he said. “We need a radical, ‘whole-system thinking’ approach to how we will heat our homes in 2050, not a blind reliance on new technologies.”
Green hydrogen has been seen as a potential substitute for heating from natural gas but it has “significant technical and serious commercial issues”, he said, while biomethane could be a “much more promising gas substitute technically, but it‘s not clear if it will ever be possible to produce this in sufficient quantity”. Heat pumps, meanwhile, are “not a direct drop-in replacement for natural gas boilers”.
District heating systems using waste heat from industry, data centres or biomass could provide some solutions, however. “The beauty of district heating schemes is that they are not dependent on a single fuel source, and any form of heat and input can be used alone or in combination with others. In most other countries, the otherwise wasted heat from steam turbine generators is one of the most important sources of district heating energy,” Arbon said.
“We must apply more holistic approaches to heat energy and utilise as much locally generated heat as possible. In addition to the many more traditional sources of waste heat, data centres offer an amazing opportunity in this respect. Instead of worrying solely about how much extra electricity they will consume, which is going to be vast amounts, site them close to new housing developments, where the equally vast amount of rejected heat can be used to heat and or cool the housing development.”
‘No single answer’ to reliability concerns
It is hard to overstate the scale of the shift in the UK’s energy mix in recent decades. Coal, once the bedrock of electricity generation, has been cut out in favour of renewables, significantly reducing the country’s contributions to carbon emissions.
There is still much hard work left to do, however. One of the key challenges is balancing supply, demand and storage across the large and dynamic system, while simultaneously preparing for a forecast doubling of electricity demand by 2050.
The appropriate solution depends on the timescale involved, said Colin Morgan from energy consultancy Everoze, with options including large battery projects, vehicle-to-grid systems and synchronous compensators. Other challenges are harder to solve, however.
“Electricity demand has a certain amount of seasonality,” he said. “[It is] higher in the winter – no surprise there – which is broadly correlated with wind generation in the UK, and very badly correlated to solar generation. We have heating, which has a very strong seasonal effect, as you would expect.” There are no “great solutions” for seasonal storage at the moment, he said.
Security of supply is another key aspect, he said, with potential threats from war, terrorism, industrial action and elsewhere. “If we design a building or a structure, we might design it to a [one in] 1,000-year event, but do we design the reliability of our electricity system to a [one in] 1,000-year event, or a lesser event? So, the more reliable we want it, likely the more it‘s going to cost us… There is no single answer to that. It‘s not just an engineering question; it‘s a society question.”
Salt caverns could be key for hydrogen power
Storage methods will have an important role to play in growth of the nascent hydrogen economy, and different applications will benefit from different storage types.
“In the context of power generation, delivery of demand requirements will be a key factor in storage selection, as high flow rates are required for combustion,” said Jamie Fuery, mechanical engineer for net zero at AtkinsRéalis. This makes underground salt caverns the most relevant storage option for power generation, he said.
Inert to hydrogen and with beneficial injection and withdrawal rates, the subsurface cavities – now empty following the extraction of salt – are a promising choice. The technique will be far from easy, however, and successful projects will face a number of challenges including cavern integrity, hydrogen purity and technology readiness.
If you were not registered for the event but would like to watch the sessions on demand for free, please contact the IMechE Event Enquiries team at eventenquires@imeche.org.
IMechE Focus returns with a week focused on Digital and Emerging Technologies, from 12-16 October. Learn more and register now.
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