Extreme space weather: impacts on engineered systems and infrastructure - .PDF file.
Despite some scary headlines, Britain is actually relatively well placed to deal with extreme space weather – but still needs to remain vigilant.
The UK needs to ready itself for solar superstorm, the Royal Academy of Engineering warned last week, prompting headlines helpfully threatening chaos and even Armageddon.
But Britain is actually already relatively well prepared for an extreme solar weather event, the experts behind the Royal Academy’s report said, advising the country to ‘prepare, not panic’ through the creation of a UK Space Weather Board that would lead attempts to mitigate the effects of a large-scale solar storm.
The Engineer went along to the launch of the report, Extreme space weather: impacts on engineered systems and infrastructure, to find out exactly what the threat is and what can be done to improve our readiness.
What is a solar superstorm?
A solar storm starts with a large burst of energy from the sun’s surface known as a solar flare, which is followed by a coronal mass ejection (CME) of charged particles, plasma and electromagnetic radiation that are fired out into space.
When the CME reaches the Earth it causes a disturbance in the planet’s magnetosphere and ionosphere known as a geomagnetic storm, which periodically releases energy that can affect a variety of engineered systems on the ground. The CME can also increase the production of secondary charged particles that cascade from the atmosphere and can also affect technology, particularly electronic systems.
Superstorms are not well defined but are essentially very intense solar storms thought to occur on average once every 100 to 200 years. The largest ever-recorded storm was the Carrington Event of 1859, which brought down telegraph networks across Europe and North America.
How much of a threat do they pose?
Prof Paul Cannon, chair of the working group that produced the Academy’s report, had this to say:
‘It’s an inevitable natural hazard and it will have a wide impact on technology. Extreme space weather has been variously described by some as inconsequential, and by others as potentially cataclysmic. Simplistically, our view is that solar super storms will be a challenge for the UK to deal with but certainly not cataclysmic. And our motto in all this is: “Don’t panic but do prepare”.
‘It will have wide ranging impacts on infrastructure, and that will include the electricity grid, satellites, aircraft and air passengers, GPS navigation sytems and mobile networks in some countries. The good news is that the UK is already better prepared than many other countries. And to further reduce risks, the Academy report is suggesting ways forward to improve our resilience.’
What are the threats to the electricity grid?
The main problem is that geomagnetic storms can induce additional current in electricity networks. This can overheat transformer cores or increase consumption of reactive power (effectively the background energy produced by the grid), destabilising the voltage and bringing down the network. The latter of these problems caused the partial collapse of the Canadian electricity grid in 2003.
In a worst-case scenario, National Grid estimates there would be some local electricity interruptions for several hours and around six super grid transformers in England and Wales (and a further seven in Scotland) could be taken out of action. ‘To put that in context, that’s six out of a population of around 800,’ said National Grid’s network operations director, Chris Train.
‘There may be circumstances where a substation, which would typically have four units in, might get hit severely, and the potential to lose one out of those four might lead to a reduction or a short-term permutation in supply, similar to terrestrial weather effects in a localised area. And that is more towards the extremities of the network and the remote locations around the UK.’
What can be done to protect the grid?
Alongside simulations, space weather monitoring and operations to reduce transformer loading, the UK’s National Grid has taken several steps to make transformer infrastructure more resilient, prompted by a major solar storm in 1989. Firstly, transformers have been resdesigned and replaced to make them more resilient to solar storms.
‘The second aspect, which is a feature of the way we design and structure our grid, is that a lot of our transformers are part loaded,’ said Train. ‘The issue of overheating cores really occurs when the transformers are full loaded, and the fact that we have a meshed lattice network with in-built redundancy for resilience means that we can cater better than other grids for this kind of event.’
He added: ‘There are additional hardening measures that could potentially be undertaken. There is a capacitor blocker currently being tested in the US. That blocks the current from going into the transformer to stop any impact from the current hitting the transformer. But when you put capacitance in the line you’re effectively interrupting the line, so you might be mitigating against a high-impact, low-probability event but creating a more frequent problem in the line.’
How will satellites be affected?
Keith Ryden, reader in space engineering at Surrey University gave this assessment:
‘Satellites are certainly in the front line in a superstorm and they of course play an increasing role in our basic infrastructure. The effects that we see would be energetic charged particles, which can interfere with and damage on-board microelectronics. Fortunately, satellites are engineered already to cope with quite a lot of space weather.
‘Also satellite engineers are extremely conservative people and they tend to put in big design margins, and we also have a big diversity of satellite designs these days. And for all those reasons, we think there will be disruption but it will be limited by those mitigating factors.
‘The study has estimated that in a Carrington-type event, extrapolating from the limited information that we have, up to one in ten satellites could have some sort of outage for hours to days during the period of the storm. We don’t know which satellites will be affected because there are so many different manufacturers and types of satellites these days.
‘Also, during the storm there will be a big dose of radiation and that will age the satellites. So we may find that some very old satellites start to have trouble in the months after the storm and we would then need to carefully consider the remaining lifetime of all satellites to decide how soon we would need to launch replacements.’
How would this affect GPS and other satellite navigation systems?
Paul Cannon, who is also Professor of Radio Science and Systems at Birmingham University, said:
‘Assuming the satellites survived the onslaught of the radiation, and we believe at least the GPS satellites will survive quite well because they are military satellites, then the superstorm will have an effect on the radio signals propagating down to the ground. It’s our estimate that we will lose GPS signals for one to three days. So make sure you still keep a map in your car.
What impact will this have on infrastructure that relies on GPS?
Cannon said: ‘GPS signals are used for timing as much as for navigation and timing is very important to our communications infrastructure. What we find in the UK is that our trunked networked communications system – our backbone fibre networks – are very, very well engineered, and although they use GPS signals for synchronisation, they actually have backup systems they can revert to, which give them holdover for three days. And when GPS comes back on again they will be able to pick up where they left off. We certainly also believe there will be edge networks, peripheral networks that will suffer the consequences of losing GPS.’
The UK’s mobile network is in an even better position and is ‘fundamentally resilient to space weather’ because it doesn’t rely on GPS for timing signals, putting us one step of the US, which does. However, added Canon, ‘there is more than a suspicion that one element of the 4G standards coming in will not be resilient to these major space weather events. So if we’re not careful, as technology evolves we’ll build in problems for the future.’
There will obviously be problems for any transport vehicles that use GPS for navigating but the shipping industry already has an alternative for coastal navigation in the form of LORAN (LOng RAnge Navigation) systems that broadcast low frequency radio signals. These are maintained by individual governments and subject to their funding decisions but recent discussions about GPS vulnerability have already prompted renewed interest in the technology and the UK recently switched on its latest generation e-LORAN system.
What about aircraft?
As well as the loss of GPS navigational systems, aircraft could suffer problems with their electronic systems, as Keith Ryden explained:
‘The same energetic particles that effect satellites will hit the top of the atmosphere and generate secondary particles. We know from extensive work dating back to Concorde days that microchips can be upset by neutrons that are generated. These effects on Concorde were not of any great significance because the electronics were very chunky and primitive but today aircraft are packed full of microelectronics.
‘During such a superstorm we would have the potential for some upsets in these electronics and that could cause some increased workload in terms of detecting and correcting any unexpected events. Generally speaking the multiple layers of safety systems in aircraft are able to mitigate most of these effects during quiet times, so our concern is mostly about the storm event, during which we think the population of these neutrons could increase by a factor of 1000 compared to the normal levels.
‘To mitigate these issues we propose further investigations and risk assessments. We should consider providing pilots with more space weather information and we should improve the engineering standards in the future, which might include testing equipment from aircraft in neutron simulators. A new facility is opening in the UK later this year at Harwell that will be able to do that.’
Ryden compared the risk to that of flying into a thunderstorm: it’s not ideal but the pilot should be able to cope if it did happen. Neutron cascades aren’t going to cause catastrophic failure and we don’t need to worry about planes falling out of the sky. But, as in other affected areas, we do need to be aware that extreme space weather can pose a danger equal to extreme terrestrial weather.
As for the danger of increased radiation from solar superstorms, Dr Jill Meara of the Health Protection Agency compared it to spending a week in Cornwall, where there is a naturally high concentration of radon gas released from the granite rocks.