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NETWORK / 29 / SEPTEMBER 2018 which launched what it claims is the world's rst 5MW /15MWh liquid air energy storage (LAES) plant in Bury in June, is developing an energy storage technology that may come to play an important role in the UK and overseas. Enough energy is now being drawn from the pilot LAES plant to power about 5,000 average- sized homes for around three hours, with the plant helping to provide reserve, grid balanc- ing and regulation services. Highview Power chief executive Gareth Brett explains that LAES can already be used to help balance the load on the grid by storing energy at times when demand is low and releasing it at times when demand is high. "As an objective, there is nothing wrong with trying to improve the overall load factor of the system. That means more e' cient use of assets." The LAES technology can also help to provide inertia on the grid by discharging small amounts of power as a frequency response service, helping to make the grid more resilient, Brett says. But Highview hopes that its technology will one day be doing much more than this in Britain, and overseas. It has the potential to be scaled up by hundreds of megawatts. Future LAES plant may be located on a footprint of about 4,000m2 next to a large solar or wind farm with the potential to power more than 100,000 homes – a town such as Bury – for many days. "The next project we are looking at would have 50MW of instantaneous discharge capability, with about 250Mwh, or ve hours, of storage," says Brett. The system is scalable, then, but it is also intended to be relatively low cost and straight- forward to maintain. Brett ex- plains: "It is electro-mechanical, and uses refrigerators, tanks, expansion turbines, pumps and heat exchangers that have a lifetime comparable to our distribution and transmission assets: 30 – 40 years." He adds: "It is not a technol- ogy that degrades during its usage: it performs the same toward the end of its life as it did at the beginning. In terms of asset management, that's important. It matches up well with the existing network. We didn't want to have a 'black box' technology, where operators and maintainers wouldn't know what was going on inside." Using robots to inspect power lines As novel means of energy storage develop on the grid – Highview's technology is likely to be part of a portfolio of storage technologies such as new batteries, as well as stalwart storage systems such as pumped hydro – networks are also continuing to innovate when it comes to understand- ing and managing their assets. Scottish and Southern Electric- ity Networks (SSEN) announced last month that it had entered into a partnership with Williams Advanced Engineering to design a functional speci cation for a live overhead line inspection robot to be used on SSEN's high voltage electricity networks. Stewart Reid, head of DSO and innovation at SSEN, says autonomous robotics have the potential to automate processes now done manually, gather increased levels of data on as- sets more frequently, and with more precision, and all without interrupting services for custom- ers. "Robotics is a no-brainer in terms of areas we should be ex- ploring," he tells Network. The robots when built might have a weight of 25 – 30kg and provide a platform for di¢ erent applica- tions, such as conductor condi- tion testing and even repairs on such systems. Traditionally, these activities would have required a shutdown. "Using a robot, we could be doing these repairs live," Reid says. The project is known as Line Inspection by Semi-Autonomous Systems (LISAS) and is being funded by Ofgem's Network Innovation Allowance. When it comes to fruition, it will be the rst time an autonomous robot has been used to inspect elec- tricity networks in the UK.£The robot will navigate its own route as it moves from overhead line to overhead line, navigating from steel tower to steel tower, capturing asset data to inform reinforcement and mainte- nance requirements. It has the potential to provide both much more asset data and new data sets, thanks to the array of samples that could be taken over a long period by a robot, and of a greater granularity than is typically available now, Reid explains. Autonomous robots would not replace drones in terms of power line inspection, he adds. "Semi-autonomous robots will give us hands-on contact with the system. They also mean you have a bigger weather window in which you can operate. This is really the next level up in terms of autonomous technol- ogy. But it will be complemen- tary to drones." Ultimately, the more data you have generated by new technol- ogies such as LIDAR scanning and LISAS, the more precise you can be about how to invest in the system, Reid says. "We will be able to be more selective about where we invest, which means savings for customers. "We will also have much greater visibility in terms of what is going on on the network – and be able to identify weak- nesses before they develop into faults." Dr Jaise Kuriakose, lecturer in cli- mate change at the Tyndall Centre for Climate Change, University of Manchester. Dr Vidyadhar Peesapat, knowledge transfer research fellow, University of Manchester. Gareth Brett, chief executive, Highview Power. Storage capacity comparison