Providing energy solutions
Will the decarbonisation of heat and the use of low-carbon gases change the face of gas networks and infrastructure? Network explores the issues.
3rd November 2017 by Networks
The announcement by Centrica in the summer that it is intending to shut down the Rough gas storage field in the North Sea marked the end of an era for one of the UK’s most important pieces of gas infrastructure.
Licenses for the Rough Field were given in 1964 and a decade later the first gas was brought ashore to the Easington gas processing terminal. Latterly, the field has served as Britain’s only economically viable depleted offshore gas storage and retrieval facility, with a capacity of more than 3.3 billion cubic metres – approximately 70 per cent of the UK’s total storage capacity, or enough for nine days’ gas supply.
Economically viable, until now. In June, Centrica Storage (CSL) said it was intending to end Rough’s status as a storage facility, and to produce all recoverable gas from the field. “As a result of the high operating pressures involved, and the fact that the wells and facilities are at the end of their design life and have suffered a number of different failure modes while testing, CSL cannot safely return the assets and facilities to injection and storage operations,” the company said.
As in power, major transitions in the gas industry are taking place. The role that gas will play in the smart grid of the future is also under scrutiny. Commentators in recent issues of Network, such as the Energy Networks Association, have said that the decarbonisation of heat is perhaps one of the most difficult issues to solve as the move to a low carbon energy system takes place. Still others have suggested that RIIO-2 must not focus unduly on power at the expense of leaving as many options on the table as possible when it comes to gas and heat.
“I’ve been a big advocate for decarbonising the heat system for more than a decade,” explains Dr Tim Fox, an independent energy consultant, and the former head of energy and environment at the Institution of Mechanical Engineers. “Electricity has been, and will be, a relatively easy low carbon challenge compared to heat. The challenge lies in the fact that most of the consumption of heat is seasonal. In winter, demand is about three times what it is in the summer. Our solution in the UK has been, since our discoveries in the North Sea, to rely almost exclusively on natural gas.”
There is a number of ways in which heat could be decarbonised in the future as part of the UK’s obligations under the Climate Change Act, but it is widely acknowledged that decarbonisation of heat, which accounts for around 45 per cent of our energy usage and 80 per cent in UK homes, is lagging decarbonisation of power and transport. Scenarios developed by KPMG show four potential ways that energy demand, particularly heat demand, could be met in 2050. These include evolution of the gas networks; an all-electric future for heat; a future in which diversified energy sources dominate, and gas networks are used in just half of the country; and a ‘self-generating’ heating and energy solutions future, with a majority of all-electric heating. In this final scenario, the majority of transport is completely decarbonised – and existing gas distribution networks are not used at all.
Moving from a philosophy in which individual gas boilers heat individual buildings supplied by an individual supply from a network, to a situation in which there are low carbon domestic, commercial and industrial alternatives is “very challenging”, Fox says. “We don’t have the range of solutions available to us we would like. From an engineering point of view, replacing the huge amount of infrastructure that has been in place since the 1980s is a real challenge.”
The KPMG 2050 scenarios note that the use of alternative low carbon gases such as hydrogen and biogas on the distribution network is technically feasible today; in fact, the use of hydrogen on the gas distribution network is already being demonstrated in Britain in Leeds by Northern Gas Networks’ H21 project. Indeed, if much of the existing gas infrastructure can be used, there is a limit on the inconvenience of the change for gas customers and society, with hydrogen fuel eventually potentially supplying both low carbon heat and also transport, if hydrogen-fuelled vehicles are adopted en masse. Conversion at scale to hydrogen will be logistically challenging, but a similar project was successfully carried out in the 1960s and 1970s when the conversion from town gas to natural gas took place. An all-electric future is also technically possible, but significant investment will be needed to meet peak heat demand, KPMG says. This will require new equipment in the home, reinforcement of electricity networks and new generation, including back up capacity for some renewable capacity at winter heating peaks. Conversion will also face design, planning, customer acceptance and funding challenges.
A diverse approach
A diversified energy sources future would require local authorities to take a lead in delivering local solutions to heat homes and businesses, says KPMG. Diverse approaches to energy will present delivery challenges in terms of design, planning, customer participation, obtaining funding, and the ability to implement change. In the final scenario, some consumers would generate their own heat energy. The technical difficulties of inter-seasonal energy storage would mean that most customers would be unable to generate sufficient heating energy. The rest would largely use grid electricity, leading to increased demand on electricity networks and generation.
One of the solutions could be the adoption of district heating systems; systems for distributing heat generated in a centralised location for residential and commercial heating requirements such as space and water heating. These might use combined heat and power, energy from biomass, or energy from waste technologies to heat homes, and have been “very successful” on the continent, says Dr Fox. Ground, water or air-source heat pumps might also be used. Individual biomass boilers fed by woodchips or pellets might present another low carbon option. Finally, solar thermal technologies have possibilities, although their effectiveness in the UK climate is diminished. “As a network engineer, if one had a blank sheet of paper, district heating with a low carbon heat source would be the desired outcome,” Fox says.
Reducing demand for natural gas in the first place would help under any circumstances. More effective insulation for housing and commercial spaces would massively aid decarbonisation of heat. “The first step in the energy hierarchy is to conserve the use of energy in the first place,” Fox points out. There is also interest in developing demand side response services for industrial users of gas, as already takes place in the electricity market. National Grid is working on developing DSR services to encourage daily metered gas consumers to offer to reduce their gas demand during times of system stress.
“Demand side response for gas is not a solution on its own, but it is certainly worthwhile developing it as part of a suite of solutions addressing the problem of gas storage and demand,” Fox says.
Northern Gas Networks sees hydrogen as playing a crucial role in future gas supply and in the decarbonisation of heat. The H21 project has demonstrated the feasibility from both a technical and economic viewpoint of converting the existing natural gas network in Leeds to 100% hydrogen. “The idea is that we prove hydrogen is a sustainable source of heat in urban areas,” explains Nick Phillips, head of strategy and asset management at Northern Gas Networks. The next step is a joint bid from the four gas networks in Britain for funding from Ofgem’s Network Innovation Competition for £15 million to demonstrate the safety case for hydrogen. A decision is expected on the bid by the end of the year. “We know hydrogen is feasible from a network point of view. We would use that funding to really demonstrate the safety case through detailed research,” Phillips says. Public acceptance and awareness would also be addressed were the network operators to get the Ofgem funding, he adds. “The vision is that we would start in Leeds, but other cities could start the transition to hydrogen as well. We would gradually join things up to form a national hydrogen network which could naturally extend to transport too.”
In terms of gas storage on networks, for the last five years Northern Gas Networks has been decommissioning and demolishing its low pressure gas holders. There has been an increase in the amount of gas stored on the high pressure system, Phillips says. “We’ve removed the need for low pressure storage. What we know is that we can now store gigawatt hour levels of energy in the high pressure gas transmission network overnight and release it instantly.
“Compare that to battery technology, where for a relatively high cost you are talking about storing megawatt hours of energy: we think the gas network has the potential to store a massive amount of energy for heat and electricity generation across the country.” There is already enough gas storage on Northern Gas Networks’ high pressure system to cope with peak demand during a winter of a severity only experienced once every 20 years, explains Phillips.
At Northern Gas Networks, the gas network is now viewed as a “giant battery”, Phillips says. If renewable energy is stored and used to create hydrogen via electrolysis, that then generates heat and powers vehicles, the system could be successfully decarbonised. Is hydrogen destined to ultimately be used in place of natural gas as part of the energy system, no matter what other changes take place? Phillips is emphatic: “Absolutely. Provided our bid is successful and we get the funding to demonstrate the safety case for hydrogen, we believe it can play a significant role in decarbonising heat and transport in the UK. We see the gas networks playing a major role in transporting hydrogen around the country. And long-term, that hydrogen will be created from renewable energy sources, not methane.”
These are all steps in a major transformation that commentators say is taking place in the UK energy system. Britain is transitioning from a top-down energy system to one that integrates thousands of small, independent clean energy providers and energy storage providers into the grid, and demand side response from industrial, commercial and domestic consumers. Fox says: “Trying to integrate that into a system that was designed very robustly for a top-down model is a major engineering and physical infrastructure challenge.”
There will also be a huge digital challenge, he says. The potential of consumer-led demand side response via smart meters is huge, but there have been widespread problems reported with the roll-out of millions of the first devices. Fox also believes the cyber security issues in terms of smart meters have not been addressed. “Devices, sensors and smart meters are open to abuse from hackers.”
Another major issue is public engagement with smart meters and other new technologies. “I think the take-up of smart meter technology has not been as enthusiastic as would one have hoped,” Fox says. Although a large number of smart meters have been deployed, he notes, they are not being used effectively. “I don’t see large scale public engagement taking place.”
Energy storage has made huge strides forward, on the other hand. But Fox says the range of commercially available devices for storage is still relatively small. “There has been a sea change in the last five years or so in terms of storage. But there is an enormous amount of work to be done.
“We need to be in a position in which there is a much broader range to the energy solutions portfolio for the future smart grid.”
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