Solar weather and EMPs both pose great threats to the United States’ power grid and need to be addressed as soon as possible.

This week, the influential and bipartisan National Conference of State Legislators (NCSL) passed a resolution urging swift action to protect our nation’s electrical grid from solar geomagnetic disturbances (GMDs) and high-altitude electromagnetic pulses (HEMP) —threats that, according to the U.S. Senate Committee on Homeland Security, “could cause the death of approximately ninety percent of the American population.”

Initially, for some lawmakers who were hearing this statistic for the first time, it seemed “alarmist” or “unbelievable,” but the reality is that a long-term widespread blackout of the American electric grid would cause extraordinary suffering and loss of life.

Some lawmakers involved in the discussions surrounding the topic found that many of their peers were generally unaware of the GMD and HEMP threats and their devastating consequences. That lack of awareness is exactly what inspired the production of an award-winning documentary narrated by Hollywood celebrity Dennis Quaid — “Grid Down, Power Up” — a film every American should watch.

New Hampshire Leadership

New Hampshire State Representative Doug Thomas (R) sponsored the resolution, co-authored by Representatives JD Bernardy (R) and Rita Mattson (R). It passed unanimously after the legislators were informed that both President Obama and President Trump had written executive orders to address these threats, but that little had been done to actually harden the electric grid.

The full text of the resolution reads as follows:

“NOW, THEREFORE, BE IT RESOLVED, that the National Conference of State Legislatures urges members of Congress and the President of the United States to initiate and coordinate efforts with state governments and the electric power sector to implement plans and preparation for the protection of electric power generation, transmission and distribution assets from EMPs and geomagnetic disturbances (solar flares); first addressing those sectors most vulnerable and with the longest lead times for repair, and then by using a risk based assessment approach to harden the remainder of nation’s electric production, transmission and distribution systems for resilience against, and recovery from, all types of malicious or naturally occurring events that could adversely impact the electric power grid.”  [Bold emphasis added.]

The resolution’s approach of first addressing sectors that are the “most vulnerable and with the longest lead times for repair” is a wise one. It echoes the recommendations of leading HEMP/GMD experts and their concerns about assets with extremely long lead times, particularly transformers.

This point bears some technical explanation —both on the HEMP/GMD threat and transformer lead times.

HEMP & GMD Effects on Transformers

HEMP and GMD both induce a quasi-DC current in the earth that travels the path of least resistance. These ground-induced currents (GICs) invade the power grid from the earth through the neutral-to-ground connection of high-voltage transformers and travel across long transmission lines, causing damage to the largest components on our power grid — transformers, high-voltage circuit breakers and large power generators — as well as the electric load. 

The strength of these GICs is measured in volts per kilometer (V/km) —a measurement that simply describes how strong the electric field is over a given distance—directly influencing how much current (GIC) can be expected to flow into the electric grid.

Thus the “V/km field strength” measurement is a big deal.

The Real-World Threat vs. America’s Defective Standards

In the 1960s, both the United States and the Soviet Union performed high-altitude nuclear tests that revealed the destructive power of HEMP. The Soviets chose a test location over an industrialized area almost as large as Western Europe —present-day Kazakhstan —and proved that a single HEMP detonation produced strong GICs that severely damaged portions of the Kazakhstan electric grid.

It is notable that the test location the Soviets focused on is at the specific geomagnetic latitude of Washington, D.C.

After Congress established the EMP Commission in 2000, the commission’s scientists received important data from Russian scientists on those 1960s HEMP tests, determining that the Soviets would have achieved a “field strength” of sixty-six V/km.

In May 2025, the International Electrotechnical Commission (IEC) —a globally recognized organization that develops and publishes international standards for electrical, electronic, and related technologies, as well as grid operations —updated its recommended HEMP protection standard (IEC 61000-2-9) to 100 V/km. 

Meanwhile, in the United States, there is no enforceable standard to protect our electric grid from the GICs generated by HEMP. 

The only protection standard we have is for GMD, and it is transparently defective —requiring protection at only two V/km in Washington, D.C. and 0.8 V/km in the southern states such as Texas and Florida. 

This means that America’s utility industry can “meet the standard” without installing any hardware to protect its vital transformers and the rest of the power grid from GIC. 

Transformer Production Lead Times

In 2018, Mr. Scott McBride, Infrastructure Security Manager at the Department of Energy’s Idaho National Laboratory (INL), testified before the US Senate, warning that “The Nation’s High Voltage (HV) and Extra High Voltage (EHV) power grid contains a few thousand large power transformers which are potentially vulnerable to the threat of GMD events” and that “These transformers are very expensive to build and typically have long lead times of eighteen to twenty-four months.”

Since then, production lead times on large power transformers have only grown. 

Last year, Utility Dive reported that the National Association of Electrical Manufacturers (NEMA) warned that “delivery of a new transformer ordered today could take up to three years,” and Hitachi Energy specified that, “transmission-scale unit lead times are now three years to six years, with specialized transformers taking the longest time.”

Those large transmission-scale transformers mentioned by Hitachi are custom-built, cost tens of millions of dollars, and are the MOST vulnerable to GICs, per their design.

Billions Lost Annually

The fact that a HEMP or large solar storm could devastate these critical assets is only part of the bad news.

The other bad news is that even minor solar storms produce harmful GICs that pass through these transformers, causing them to induce harmonics that ruin downstream equipment —producing economic losses in the United States of approximately $10 billion each year. 

That statistic comes from the rigorous statistical analysis of the highly credible Swiss-based global insurer Zurich, in its 2015 study titled “Electric Claims and Space Weather,” which drew upon previous joint research between Zurich, Lockheed Martin, and the National Oceanic and Atmospheric Administration (NOAA).

The Good News: A Protection Solution Exists

As Mr. McBride shared with the Senate in 2018, “A mature, tested, and validated technology has been developed and represents one potential solution to protect HV and EHV power transformers from the threat of both GMDs and EMPs…the EMP hardened transformer Neutral Blocking Device (NBD) … marketed as SolidGround®.”

“At this time, there are three such SolidGround® NBD devices installed in the American electric grid that have automatically operated over 150 times whenever GIC is present without fail.”

SolidGround®, produced by EMPRIMUS, simply attaches to the neutral ground cable of a transformer, blocking GIC at the point of entry before it enters the grid. This device has undergone extensive testing by academia through the University of Manitoba, by the government through the Department of Defense’s (DoD’s) Defense Threat Reduction Agency (DTRA), the Idaho National Laboratory (INL), and the Oak Ridge National Laboratory (ORNL).

SolidGround® was also purchased, installed, and validated by the Department of Energy (DOE) per President Obama’s Executive Order 13744, through public and privately owned utilities such as American Transmission Company (ATC), the Western Area Power Administration (WAPA), the Tennessee Valley Authority (TVA), and even through the utility industry’s Electric Power Research Institute (EPRI), which has studied SolidGround® extensively.

Outside of the United States, other countries have tested SolidGround® and are beginning to install them on their nation’s most critical transformers.

More Good News: Protection is Affordable

The other good news is that protecting America’s roughly 6,000 identified “high-risk design” critical large power transformers is affordable. Unlike massive, custom-built, multi-million-dollar transformers, SolidGround® is not custom-made but a standardized “one size fits all” device able to be produced on an assembly line. It costs about $500,000, and can be licensed to major transformer manufacturers to rapidly scale up production and deployment across the United States.

Employing SolidGround® to block GIC not only protects those critical transformers but also protects the rest of the grid from these transformers, which, if left vulnerable during a future massive GMD or HEMP event, would take down the rest of the grid, damaging components with GIC-induced VAR losses and harmonic generation. This is what collapsed Quebec’s electric grid in 1989 during a relatively minor GMD event (~ 2V/km). 

According to McBride, “There must be a priority to protect the most critical large power transformers in place —my preliminary estimates are that this would cost less than $4 billion if we made it a priority to install NBDs at our most critical EHV substations.” That cost estimate was validated by the nonprofit Foundation for Resilient Societies (pg. 63) and the independent analysis of ABB, Inc., which owns the largest collection of transformer designs in the US fleet.

Investing $4 billion to block GICs nationwide and defend some of the grid’s most critical assets from HEMP would help deter our adversaries from using that method of attack. It would also save the American economy $10 billion in annual economic losses from routine solar weather and protect against large GMD events, which we cannot deter and are statistically certain to impact Earth in the future. In 2013, Lloyd’s of London estimated the economic cost of a large “Carrington-class” solar storm (which occurred in 1859) on the North American grid today at between $0.6 and $2.6 trillion based solely on the value of lost load.

It’s Time for Action

So, if the president and Congress were to act on the NCSL’s recent resolution, the most important first step they could take would be to listen to Mr. McBride’s 2018 recommendations by immediately protecting our nation’s large power transformers from GIC.

Ninety-plus percent of our population’s lives depend on it.

About the Author: Lt. Col. Tommy Waller, USMC Ret.

Lt. Col. Tommy Waller is the President & CEO of the nonprofit Center for Security Policy. Waller retired from the U.S. Marines after two decades of service in both active duty and the reserves as an Infantry and Expeditionary Ground Reconnaissance Officer with deployments to Afghanistan, Iraq, Africa, and South America and with cross-assigned service to the U.S. Air Force’s Electromagnetic Defense Task Force (EDTF). His formal education includes numerous military schools and colleges, a degree in International Relations from Tulane University, and executive education from the Wharton School. In addition to running the Center for Security Policy, he also manages the nationwide bipartisan Secure the Grid Coalition. [The Center for Security Policy is a 501c3 nonprofit that receives no funding from governments, foreign sources, or corporations that can profit from the organization’s policy recommendations.]

Image: Shutterstock/IHX

The post National Conference of State Legislators Urges Grid Protection from Solar Weather & EMPs appeared first on The National Interest.