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What happens when the lights go out? Its time to think about resilience…

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John Armstrong's picture
Chief Operating Officer BPA

John Armstrong is an engineer whose career has spanned the extremes of the energy industry – giving him a front-row seat on the energy roller-coaster. He began his career constructing oil...

  • Member since 2019
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  • Mar 27, 2020

At 4:52pm on Friday 9th August a lightning strike hit a transmission circuit at 4.5km from the Wymondley substation. It was a pretty normal day in the UK transmission system but that single bolt of lightening caused significant disruption. Trains were stopped for hours and the country took a significant time to recover.

‘Prior to 4:52pm on Friday 09 August Great Britain’s electricity system was operating as normal. There was some heavy rain and lightning, it was windy and warm – it was not unusual weather for this time of year. Overall, demand for the day was forecast to be similar to what was experienced on the previous Friday. Around 30% of the generation was from wind, 30% from gas and 20% from Nuclear and 10% from inter-connectors’ Report into to the events on Friday 09th August.

The lighting that hit a powerline at 4.42 turned off the power to over one million people. Although power was restored within an hour the impact went on late into the evening and was particularly felt in the rail system where one fleet of trains couldn’t reset themselves when the power returned. This caused significant disruption (and discomfort) for those stuck on the trains awaiting to be rescued.

Was it Wind and Solar’s fault?

Much has been made in the press of the changing nature of the electricity grid and the impact of more generation embedded in the system. The image below shows the dramatic changes in sources of power supply over the last decade…

The Energy System in 2008 and 2018

The Energy System in 2008 and 2018 (Dots show generation sources) – Interactive Carbon Brief

Logically more decentralisation should build in resilience as large single points of failure disappear. However it is clear from the August power cuts that these key single points still exist. In such a complex interdependent system small disruptions can still have a much broader impact. Although in this case the lightening strike actually caused a very short term impact – it was the lack of resilience of certain critical elements to voltage drops which caused had the largest effect. Had the trains been able to be restarted by the drivers for example the impact would have been significantly reduced.

In thinking about energy resilience its important to not use just past events to plan for the future. In many ways the root cause is of less importance than the impact. A quick read of the list of global power outages shows the broad range of root causes which can impact the system. Many of which are beyond our control such as:

  • Weather Events – If you look at large blackouts around the world many are caused by large storms and in particular ice build up on power lines and lightening.
  •  Solar Storms – According to scientists space weather impacting IT systems and electricity grids is inevitable!
  • Technical Failure – Sometimes equipment does fail like in the London Blackouts in 2003.
  •  Third party intervention – a digger hitting a cable or a cyber attack.

So what can we do?

All of the above events (and many more) can all cause electrical systems to shut down. You can’t plan and prepare for every eventuality however what you can do is test systems for recovery and assess potential impacts. Following the August power cuts its important for organisations (and individuals) to consider:

-       What is the impact of even a short interruption to key supplies (power, water, gas etc) to our activities and in particular our customers?

-       Is there any way to physically test how we would recover in the event of a loss of critical supply? (even a short one!)

-      Can we look for ways to build in natural resilience into our systems? Renewable technology gives us chance to build in resilience, for example through Local Energy Systems.

As the system evolves and further decentralises considering our own more local systems becomes increasingly important. A decentralised system can be both more and less resilient in different ways and users need to consider in such a rapidly changing environment how best to mitigate the impact of system disruptions.

Energy from Space


Earth Photo by NASA on Unsplash

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Mark Howitt's picture
Mark Howitt on Mar 30, 2020

Many battery operators have claimed that they were part of the solution, because they got over 800MW onstream within 2-5 seconds - only, they were overwhelmed by secondary and tertiary trips. This is not true: it's that 2-5 second delay (which is intrinsic to any DC-connected systems to synchronise to the grid) that caused the subsequent trips.

How different it would have been with sufficient large-scale long-duration storage on the grid, like our own. Because all such storage uses large machines, AC connected to the grid and therefore provide real inertia - together with real reactive power/load, and real (hence more energy-efficient) voltage and frequency control. Ours can do that 24/7, regardless of whether charging, discharging or neither. Unless we get sufficient such storage onto the grid, the energy transition will be enormously costly and disruptive.

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