With the solar maximum imminent if not already present, strong solar storms and extreme space weather events can be expected that could impact the power grids.

The weather, traditionally a favourite topic of conversation for the British, has also now become a top talking point for energy professionals.

From the need for resiliency to withstand the growing prevalence of extreme weather events to that for more frequent and accurate forecasting for intermittent renewable energy dispatch, the weather is of greater interest than ever for people across the spectrum.

But that is the Earth’s weather and space weather, a consequence of emissions from the sun, also is attracting growing interest as it too can have widespread impacts.
Changes in the appearance of the sun have long been observed historically, but since as far back as the 1840s it has been known that its activity varies on an approximately 11-year cycle, now known to be due to changes in the magnetic field.

At the maximums there are large numbers of sunspots and other events such as solar flares and coronal mass ejections, while at the minimums there is little such activity.

These phenomena also can cause more extreme space weather if they are directed towards the Earth. Though space weather is always present, in the form of the charged particles that make up the ‘solar wind’, the extra radiation that is emitted in a flare or coronal mass ejection can cause stronger solar storms, with potential impacts including damage to satellites in space, interference to electronic communication and disruption of the power grids on Earth.

The most severe event recorded so far is the so-called ‘Carrington event’ of 1859 (named after British astronomer Richard Carrington, who was one of the first to observe it), which included widespread telegraph communication failures and the presence of auroras, normally seen only at high latitudes, as far south as the Caribbean.

Perhaps the best known case of a power grid disruption is the geomagnetic storm of March 1989, which caused Hydro-Quebec’s power grid to collapse with a 9-hour blackout and also damaged a transformer in New Jersey.

Space weather forecasting

As the number of satellites in space has grown and as society has become increasingly more digitalised, the appreciation that a solar storm on the scale of the Carrington event could have major consequences on Earth, both practical and economic, has led to growing activities in the last decade or so, particularly around forecasting.

In particular the maximum of the current solar cycle, which has been building up and is current or imminent likely by the end of 2024 – it can be determined only after its occurrence – has further accelerated this interest as it is turning out to be particularly active.

Forecasting the impact of solar events is generally challenging until they approach the Earth, which is typically days after the event although in the case of the Carrington event is believed to have been about 18 hours.

But space weather forecasting is now widespread by meteorological and space agencies, such as the National Oceanic and Atmospheric Administration (NOAA) with its Space Weather Prediction Centre in the US, the Met Office in the UK and in Europe ESA with its Space Weather Office.

There are even smartphone apps aimed primarily at aurora watchers.

In December 2023 in preparation for the solar maximum, the NOAA signed an agreement with NASA, the National Science Foundation and the Department of the Air Force to collaborate on improving space weather forecasts and services.

Further improvements are also anticipated from new technologies, such as the June launched GOES-19 satellite with its improved magnetometer and its data now becoming available.

In China, the ‘Chinese Meridian Project’ has been established as a ground-based space environment monitoring network consisting of nearly 300 monitoring instruments installed at 31 observation stations distributed across the Chinese mainland and the polar regions.

Based on this newly completed project, which has been under development in phases since 2008, Chinese scientists are promoting an ‘International Meridian Circle Programme’ to establish a global ground-based network with full latitude and day-and-night solar storm tracking and monitoring capability.

Mitigating solar storms

While it is not possible to avoid either Earth or space weather, being forewarned with forecasts is being forearmed, whether they come from one of the agencies, or as a service – an area that is likely to grow.

An example is the newly launched Ensemble Space, a Maryland based spin-off from the digital services contractor Ensemble Consultancy.

There also are steps that can be taken, as New Zealand transmission company Transpower has demonstrated.

A pioneer in solar storm mitigation since the early 2000s, working with University of Otago researchers and other industry partners, the company has developed and evolved a mitigation strategy in the form of targeted line disconnections.

In the research, just 24 lines disconnected were found to reduce the risk of a storm-induced current by 16% for 27 of the top 30 at-risk transformers.

Demonstration of its effectiveness came in May 2024, when a strong ‘G5’ level storm occurred with no impact on the country’s electricity supply or damage to the equipment.

“It’s just really satisfying to be able to take decades of background preparation and doing research to the point that I can do something applied that is apparently useful,” said Professor Craig Rodger, from the University’s Department of Physics, who with research associate Daniel MacManus had advanced the strategy and advised Transpower during the event.

The researchers also found in their simulations that capacitor blockers at specific transformers could reduce the storm-induced current risk by an additional 16% and Transpower is now considering this further mitigation.

Commenting on the event, Transpower summed it up saying that although there was no impact on electricity supply, it “is a good reminder to (New Zealanders) be prepared for a natural disaster or other major event that could interrupt their power supply and damage other infrastructure.”