And yonder shines Aurora’s harbinger

The spectacular aurorae that were recently seen by millions of people in parts of the world they don’t usually appear in were truly incredible, and a reminder of the beauty and the wonder of the universe. However they also brought to mind another threat to the global energy system, and society, that we really ought to think about – the threat of electromagnetic pulse disrupting the power and communication grids. I know we have more than enough to worry about, what with the worsening effects of climate change, Gaza, the Russian invasion of Ukraine, Russian and Chinese aggression in several parts of the world, and the rise of authoritarianism and last bit not least the risk of Trump being elected President of the US. But the threat of a major electromagnetic pulse also needs to be on the worry list.

The effects of electromagnetic pulse (EMP)
All electrical and electronic systems can be affected by an electromagnetic pulse (EMP), also referred to a transient electromagnetic disturbance, which is a brief burst of electromagnetic energy which can either occur naturally, such as from solar storms, or be created by the use of a nuclear (1), or specialised non-nuclear (2), weapon. An EMP can occur as an electromagnetic field, as an electric field, as a magnetic field, or as a conducted electric current – all forms of electromagnetic interference (EMI). The electromagnetic interference caused by an EMP can disrupt communications and damage electronic equipment and power grids and many such instances have occurred, including the following.

In 1972 there was major disruption of telephone lines in the US Mid-west.
In March 1989, a solar storm over Quebec caused a province-wide power cut which lasted nine hours.
A 2003 storm temporarily disrupted satellite services, and in one case permanently damaged space borne infrastructure.
In 2017 a geomagnetic storm affected radio frequency and satellite communications around the world, as well as Position, Navigation and Timing satellites.

Although there haven’t been that many reports of damage by the May 2024 solar storm some did occur. The broadband internet connection provided by Starlink reported some temporary degradation in the quality of its signals, and radio and GPS systems experienced some problems. In anticipation of the extreme solar activity, New Zealand’s electrical grid operators took protective measures and temporarily turned off some circuits around the country to prevent equipment damage. Although not damaged, some satellites did stop making scientific observations during the storm.

Solar storms
The recent aurora were the result of an extreme solar storm. Solar storms, which result from disturbances on the Sun can affect the entire solar system, including the Earth and its magnetosphere and the frequency and severity of solar storms is related to the eleven-year solar cycle which reaches its next peak in 2025. Solar storms are caused by sun spots, disturbances in the sun caused by concentrations of magnetic flux that inhibit convention. The cluster of sun spots that caused the recent electromagnetic pulse responsible for the aurora is around 17 times as wide as Earth. Around 8 May, this active region sent at least seven coronal mass ejections, (blasts of magnetized plasma), towards Earth at speeds of up to 1,800 kilometres per second. These waves of charged plasma swamped space-weather detectors. On the scale of one to five that describes geomagnetic storms, this one ranked a five and according to an index of changes in Earth’s magnetic field it was a ‘super storm’.

Scientists expect the current solar cycle to peak in July 2025 and the biggest storms typically happen months to years after the peak. As the solar cycle progresses, sunspots tend to appear closer to the Sun’s equator, increasing the chances of coronal mass ejections that will head directly for Earth rather than out into space,

The Carrington Event, in September 1859 is usually known as the most intense solar storm in recorded history, and created aurora as far south as Havana and bright enough to read by as far south as Missouri. Similar scale events also occurred in 1879 and 1921. On 23 July 2012, a coronal mass ejection, (on the same scale as the Carrington event), narrowly missed Earth (3).

With our dependence on electrical devices and electronic systems increasing as we electrify our energy and transport systems, our vulnerability to the threat of EMI is growing. The scale of the economic damage that could result from a major solar storm was highlighted by joint research at Lloyds of London and Atmospheric and Environmental Research (4) in the US in 2013 which estimated that a Carrington Event scale solar storm today could result in between 20 and 40 million people being at risk of extended blackouts lasting between days and months, and a total economic cost of between $600 billion to $2.6 trillion. Electrical distribution systems, communications systems, all electronic devices and modern vehicles would be taken out of operation by such an event. The delays in restoring power would primarily be driven by the long-lead times on major equipment such as grid-scale transformers. Although the probability of a Carrington scale storm may be small, the impacts would clearly be very large.

Of course EMP can also be caused by nuclear weapons. A limited nuclear exchange using EMP weapons would be devastating and are very well described in ‘One Second After’, a novel by William Forschten (5), which was cited in the US Congress.

We need to increase resilience

The need to increase the resilience of critical infrastructure in response to a whole range of threats including EMP, is recognised by the National Preparedness Commission in the UK (6) and the Cyber Security and Infrastructure Security Agency in the US.

In summary, EMP is a major risk for the power grid and for critical systems and infrastructure such as solar farms and data centres, which are increasingly dependent on electronics and computers, a risk that will grow as the world continues to electrify at exponential pace. There is a technology that can reduce the vulnerability of such systems, High Frequency Alternating Current (HFAC). HFAC, in which AC fluctuates in kilohertz or megahertz rather than the conventional 50 to 60 hertz, was first promoted by Nikola Tesla and after several false starts over more than 100 years it is now finally being commercialized together with some breakthrough EMP technology by a UK company, Energy Research Lab. Widespread use of HFAC would mitigate the risk of EMF as well as bring considerable benefits in terms of energy and material savings. As we increasingly electrify the global economy, we need to consider the risks from EMP and adopt technologies to mitigate the risk.

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I rarely, if ever, quote Shakespeare, (probably due to bad memories of school days having to read several plays), but here is the whole quotation the title of this piece comes from.

And yonder shines Aurora’s harbinger,
At whose approach, ghosts, wondering here and there,
Troop home to churchyards. Damned spirits all.
A Midsummer’s Night Dream, Act 3, Scene 2

References

(1) EMP from a nuclear weapon is abbreviated as NEMP, Nuclear Electromagnetic Pulse, when it is necessary to distinguish it from a naturally occurring EMP. (2) For a discussion of non-nuclear EMP weapons see:
https://science.howstuffworks.com/e-bomb3.htm
(3) Near Miss: The Solar Superstorm of July 2012. NASA. 2014.
https://science.nasa.gov/science-research/planetary-science/23jul_superstorm/
(4) Solar storm risk to the North American electric grid. Lloyds. 2013
https://assets.lloyds.com/assets/pdf-solar-storm-risk-to-the-north-american-electric-grid/1/pdf-Solar-Storm-Risk-to-the-North-American-Electric-Grid.pdf
(5) One Second After.
https://www.onesecondafter.com
(6) UK Severe Space Weather Preparedness Strategy. September 2021.
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1020551/uk-severe-space-weather-preparedness-strategy.pdf