Utility Week

22 | 2ND - 8TH NOVEMBER 2018 | UTILITY WEEK Operations & Assets Northern Gas Networks: using gas for electricity storage Northern Gas Networks (NGN) has been investigating how the gas network can sup- port decarbonisation by using hydrogen to store and transmit surplus power. Sheffield-based energy and clean fuel company ITM Power approached NGN and proposed the trial of an electrolyser it had developed. This would use water and elec- tricity to turn excess power into hydrogen, injecting it into the natural gas network and using it as a renewable energy store. This could then be used in heat, electricity generation or transport via hydrogen fuel cell vehicles. Such a system could provide an alterna- tive to batteries as storage, explains Keith Owen, NGN's head of systems development and energy strategy. "Batteries are good, but it's about identifying as many options as we can within the UK to broaden the spectrum of what's possible," he says. "By taking excess electricity energy from the grid, in effect power-to-gas technology is allowing more renewables on the system. "Also, because you're putting hydrogen into the gas grid, you're decarbonising that as well," he adds. "It doesn't 100 per cent decarbonise heat, but it's a movement away from using pure and natural gas." The study examined potential deploy- ment of large-scale storage capacity of 50MW and above within the boundaries of NGN's distribution network. Follow- ing detailed analysis of NGN's network, accounting for seasonal variations in gas demand and the amount of hydrogen able to be produced and blended with natural gas, it revealed a large area of the NGN grid could support power-to-gas. The results were better than expected, Owen says. "We thought there would be parts of the network that would be appro- priate for power-to-gas, but I was quite sur- prised at how available our network was." The study tested a 50MW contribution from hydrogen, which the team considered quite a high proportion to blend into the network, he says. "I thought maybe there'd be two or three connection points that would be appropriate. But we found five. We also found a number of sites and were operat- ing a 10-20MW position, the number of opportunities was far greater. We didn't expect to see that. The team then tested the system with 100MW of hydrogen, and found one site on the network that could handle that, Owen says. "That was quite an exciting place to be – there are larger networks out there than ours, so that bodes really well nation- ally for what you can do in Scotland or the Midlands." NGN now plans to test the technology at its Integrated Transport Electricity Gas Research Laboratory (InTEGReL) in Gates- head, an incubator it launched last year with Northern Powergrid and Newcastle University specifically to demonstrate inte- grated energy system technology. Electricity North West: Smart Street and Class ENW based two of its innovation projects on the knowledge that the average domestic customer's voltage typically varies between around 225V and 250V, with no visible effect on appliances. They asked themselves how varying customers' voltage by a tiny fraction could increase grid capacity, while also sav- ing the customer money. Its Class project investigated how this concept could be used to remove the need to have back-up generation to stop the lights going out during outage of a power station or interconnector. Although this only happens four of five times a year, consumers have to bear the cost of back-up generation being on standby. As well as being expensive, it is also carbon intensive because it is typically provided by coal or gas, explains Steve Cox, ENW's engineering director. "We know that appliances use more or less electricity depending on what you do with the voltage. But what happens if you change all voltages across the network at the same time you lose the power station? If we turn the voltage up 3 per cent, a kettle will boil a litre of water eight seconds faster, and if I turn it down by 3 per cent, it will take eight seconds longer. Most people won't notice the difference. "But if you do that, not to one kettle, but to millions of homes at the same time, you can effectively create more than a nuclear power station's worth of demand reduction. It's very significant in size, but relies on only a tiny bit from each customer," he explains. The beauty of it is that it uses equipment that is already there, and does not need to be fed by fossil fuels, he adds. ENW plans to sell this balancing service to National Grid, with customers receiving a direct reduction in the network component of their bill. ENW piloted the concept on 400,000 cus- tomers, with post-trial surveys reporting no problems with household appliances. The second phase of the project investigated how voltage control could be brought to market and the benefits shared with customers. "The regulatory mechanisms are quite com- plex, but unless they're aligned properly, some savings don't automatically transfer to customers. We needed a clear directive from Ofgem on that," Cox explains. It also considered whether it should sell the demand response to suppliers via an aggregator. However, Ofgem allowed it to sell it directly to avoid customer benefits being reduced through the aggregator tak- ing its share, he says. ENW is now rolling the using the electricity when its available at a lower cost." Next steps planned by the DNO include developing the commercial proposition to introduce "heating as a service". Rather than paying for gas and electricity supply, house- holds would pay a fixed fee for heating, with the equipment provided free. The heat ser- vice provider would recover the cost from continued from previous page the savings they make using the flexibility on people's homes. The DNO wants to test adding other smart-controlled appliances such as fridges and washing machines on to the Freedom system to boost the options for household- ers to provide flexibility to the grid. It is also looking at the feasibility of introducing hybrid heat in non-domestic settings such as shops, schools and offices. THE INTEGREL) TESTING FACILITY IN GATESHEAD

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