The disruptive power of space weather often hides behind the wonder of the auroras for many people. But the most severe space weather events have the potential to disrupt electricity grids, and the reason behind this goes back to an English physicist whose ideas are still taught in school today.
As part of a new Met Office YouTube exclusive series Deeper Dive, host Alex Deakin sat down for an in-depth discussion with the University of Otago’s Professor Craig Rodger, who is an expert on space weather and its impacts on the electricity network.
As part of a wide-reaching discussion on space weather, its physics and impacts, Craig reflected on the fundamental reasons why the electricity grid is something that can be particularly sensitive to severe space weather events, and this being one of the reasons why space weather forecasting is so important.
“We have to go back to some high-school physics – Faraday’s Law of Induction – which shows that a changing magnetic field will induce a current in a conductor,” said Craig.
“Michael Faraday, famous British physicist, showed in 1831 that a changing magnetic field will induce an electrical current on an electrical conductor. Basically, if you have a wire and you wave a magnetic by the wire, you will induce an electrical current.
“But if you go to a much bigger scale, you have an electricity grid and the magnetic field of Earth that is changing fast because it has been compressed by a coronal mass ejection. This compression is linked to the aurora, but those currents will be changing the magnetic fields on the surface of Earth as well.”
Impacts of space weather on electricity grids
While impacts to electricity grids are reserved for the most severe space weather events, preparedness is the key to mitigating the worst impacts, with the Met Office Space Weather Operations Centre one of a handful of 24/7 space weather forecasting centres in the world.
Speaking to Deeper Dive, Craig explained how these currents can cause issues to power grids.
He said: “With a large coronal mass ejection, you end up with currents in the power grid that aren’t meant to be there. Unfortunately, those currents are bad for the transformers that are the building blocks of a power grid.
“Transformers transform the current. They basically take it from a very high voltage that is good for moving power between cities down to a lower voltage which is more appropriate for us to use. The extra currents are the issue and can [in rare cases] cause outages for some transformers.”
In the UK, MOSWOC works closely with government and industry partners to ensure the electricity network is well‑informed and resilient. Fortunately, such strong space weather events are rare, though preparedness requires a global effort according to Craig.
“These issues are in an extreme space weather event. For the modelling we’ve done in New Zealand we believe the risks starts getting more real for the events that are possible roughly every 75 years to once every 100 years. Coming from a country where we think about earthquake and volcano risks that maybe more like once in a thousand years, this is actually a little bit disturbingly common.”
In-depth space weather discussion
Hear more from Craig via Deeper Dive on YouTube. As well as electricity grids, Alex and Craig explore space weather scales, how forecasts work, the basics of space weather as well as international collaboration being key for future preparedness.
Image: Richard Ellis.