Utility Week

30 | OCTOBER 2021 | UTILITY WEEK Customers Event Black start with green power? How can we restart the network after a major outage using wind and solar? Utility Week and National Grid ESO brought together experts to discuss a pioneering project attempting to do just that. T he events of 9 August 2019 are indel- ibly etched on the memories of net- work engineers and business leaders. On that summer's day large parts of England and Wales were le• without electricity fol- lowing a major power cut that had a serious impact on rail and road services. Passengers were shut out of some of the country's busi- est train stations during the Friday evening rush hour, while hundreds of thousands of homes were le• without electricity. The investigation that followed found that the combined loss of two large genera- tors a•er a lightning strike, as well as the smaller loss of generation at a local level, together triggered the subsequent disconnec- tion, loss of power and disruption to more than one million consumers. A few years earlier on 5 December 2015, Storm Desmond caused unprecedented flooding in north Lancashire and Cumbria. In Lancaster, the main electricity substation was flooded, cutting electricity supply to 61,000 properties. The loss of power quickly affected other vital services. The mobile phone network, the internet, television, DAB radio and so on, were all knocked out. The energy system in the UK boasts a 99.9 percent resilience and we've never experi- enced a national blackout. But the absence of a plan to deal with low probability high impact events have untold consequences. So though highly unlikely we still need a back- up plan to restart the grid as the energy sys- tem undergoes seismic change transitioning to net zero. For the past three years National Grid ESO The mainly Ofgem-funded project, with partners SP Energy Networks and TNEI, began in 2019 setting out the scope. In 2020 it explored detailed design options and in 2021/22 moves into live trials to demonstrate whether the designs work or not. Not only was the project a world first, if successful it would help in the drive to deliver net zero, open up the market to distributed energy services, and accelerate regional res- toration timescales, said Chandler. The programme has been split across four workstreams: • Power engineering and trials; • Organisational, systems and telecommu- nications; • Procurement and compliance; • Knowledge and dissemination. The aims of the project were also aligned to a new resilience standard being issued by BEIS (the Department for Business, Energy and Industrial Strategy) for the restoration of energy services. Chandler said that the project's aim also dovetailed with enhanced resilience require- ments from BEIS being set out in a new Elec- tricity System Restoration Standard. The standard is intended to reduce restoration time across Great Britain and ensure a con- sistent approach across all regions and is expected to be operational by 2026. It will require the national electricity transmission system to have sufficient capa- bility and arrangements in place to restore 100 per cent of the country's electricity demand within five days. BEIS stipulates that it should be implemented regionally, with has supported an unprecedented innova- tion project known as Distributed ReStart to explore the potential for black start services to be provided by distributed renewables such as solar, wind and hydro and other low carbon energy generators. As this project draws to a close, Util- ity Week and National Grid ESO brought together a range of energy system stakehold- ers to discuss their hopes and expectations for the future of black start services in a net zero world and provide some feedback on the Distributed ReStart programme. The far-ranging and insightful discussion also touched on a range of issues: how well are we equipped to restore power quickly as distributed energy becomes more perva- sive and weather becomes more turbulent? Where are the weak links? And are we learn- ing the lessons from events in the past? Here are some of the key themes. Distributed ReStart Peter Chandler, power system manager and lead for NIC Project Distributed Restart at National Grid ESO, began with a project recap. Instead of the traditional "top down" approach to black start, which creates islands of thermally generated power, Chan- dler said the initiative explored whether distributed energy resources (DER) alone could do the same job in a "bottom up" way to generate clusters of clean power on local networks. This would scale up to the high- voltage transmission lines, gradually restor- ing grid power.

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