New Hampshire HB 1723: requiring utilities and electric grid operators to assess and report the vulnerability of high-voltage transformers to geomagnetic and electromagnetic disturbances, and to recommend mitigation measures to protect the state electric infrastructure.

Bill Text

HB 1723 - AS AMENDED BY THE SENATE

12Mar2026... 0935h

04/09/2026 1307s

05/14/2026 1811s

2026 SESSION

 26-2705

 06/08

HOUSE BILL 1723

AN ACT requiring utilities and electric grid operators to assess and report the vulnerability of high-voltage transformers to geomagnetic and electromagnetic disturbances, and to recommend mitigation measures to protect the state electric infrastructure.

SPONSORS: Rep. Mattson, Ches. 18; Rep. Cole, Hills. 26; Rep. Qualey, Ches. 18; Rep. Sabourin dit Choiniere, Rock. 30; Rep. Schneller, Hills. 2; Rep. D. Thomas, Rock. 16; Rep. Vose, Rock. 5; Rep. Ammon, Hills. 42; Rep. McGhee, Hills. 35; Rep. Mary Murphy, Hills. 27; Sen. Innis, Dist 7; Sen. Ricciardi, Dist 9

COMMITTEE: Science, Technology and Energy

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AMENDED ANALYSIS

 This bill directs the Department of Energy to investigate vulnerabilities of electric transmission transformers to geomagnetic and electromagnetic disturbances and report findings with recommendations.

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Explanation: Matter added to current law appears in bold italics.

 Matter removed from current law appears [in brackets and struckthrough.]

 Matter which is either (a) all new or (b) repealed and reenacted appears in regular type.

12Mar2026... 0935h

04/09/2026 1307s

05/14/2026 1811s 26-2705

 06/08

STATE OF NEW HAMPSHIRE

In the Year of Our Lord Two Thousand Twenty-Six

AN ACT requiring utilities and electric grid operators to assess and report the vulnerability of high-voltage transformers to geomagnetic and electromagnetic disturbances, and to recommend mitigation measures to protect the state electric infrastructure.

Be it Enacted by the Senate and House of Representatives in General Court convened:

 1 Short title. This act shall be known as "Survey All Vulnerable Electric Transformers Act."

 2 Findings.

 I. America’s electric grid is critical to modern life and faces existential threats from solar weather events (coronal mass ejections—CME), geomagnetic disturbances—GMDs, and high-altitude nuclear electromagnetic pulse—HEMP, all capable of disabling electric power systems.

 II. High voltage transformers are especially vulnerable to geomagnetically induced currents—GICs—whether induced by GMDs or HEMP E3 component, entering the grid through ground-connected neutral wires.

 III. Extra High Voltage (EHV) transformers (345 kV–765 kV) are most vulnerable and difficult to replace, with production lead times of up to 4–6 years.

 IV. GIC vulnerability is influenced by transformer characteristics, ground conductivity, and the magnetic field intensity from GMD or E3 HEMP.

 V. Aging transformers are more susceptible to GIC due to degraded insulating oil and coil condition.

 VI. Federal and international standards highlight the importance of transformer assessment and protection against these threats.

 VII. On July 23, 2012, a powerful CME erupted off the back side of the sun racing through Earth’s orbit missing Earth by 9 days. It was measured by STEREO-A satellite and determined by the National Oceanic and Atmospheric Administration to be in all respects at least the size of the Carrington event of 1859.

 VIII. In 2012, the United States Department of Energy’s Idaho National Laboratory working with the United States Department of Defense’s Defense Threat Reduction Agency conducted live grid E3 HEMP tests to analyze GIC harmonic threats to the electric power grid. The results showed transformer half-cycle saturation and generation of harmonics that exceeded the IEEE 519 Standard with GIC of 15 Amps in the neutral of the power transformer.

 IX. In February 2013, the North American Electric Reliability Corporation (NERC) GMD committee of 8 respected space weather scientists estimated a reference storm. Preliminary results showed a peak electric field strength of 30 V/km to 40 V/km.

 X. In May 2025, the International Electrotechnical Commission (IEC) updated the international standard IEC 61000-2-9 for E3 HEMP to 85 V/km.

 XI. The NERC GMD Standard requires New Hampshire to model roughly 3 V/km.

 XII. With the existence of validated GIC mitigation hardware that protects power transformers and improves grid resilience against these severe GIC events, reliance on load shedding or operating procedures which cannot block GIC are no longer justified.

 3 Geomagnetic and Electromagnetic Disturbance Electric Transmission; Department of Energy; Vulnerability Investigation.

 I. The department of energy shall investigate the vulnerability of electric transmission transformers and other system components to geomagnetically induced currents. The investigation shall answer the following questions: 

 (a) What studies and assessments have previously been performed that reviewed transmission system vulnerabilities to g