Governor Kelly Ayotte signed HB 1723 into law on July 10, 2026, enacting it as Chapter 310 of the 2026 session. Cited as the "Survey All Vulnerable Electric Transformers Act," the law takes effect September 1, 2027, and passed the legislature with strong Republican sponsorship, 11 to 1 among named sponsors.
The law directs the New Hampshire Department of Energy to investigate the vulnerability of electric transmission transformers and related grid components to geomagnetically induced currents, which can result from solar-driven geomagnetic disturbances or high-altitude electromagnetic pulse events. The department must begin its investigation within 120 days of the law's effective date and complete it within 12 months. The review must weigh two competing standards. NERC's geomagnetic disturbance planning guideline calls for modeling a field of 3 volts per kilometer. The International Electrotechnical Commission's updated standard for electromagnetic pulse effects, adopted in May 2025, sets the bar far higher, at 85 V/km. The department must also estimate what a reassessment at the higher standard would cost and how long it would take.
The department must share its findings widely. Recipients include the House Science, Technology and Energy Committee, the Senate Energy and Natural Resources Committee, and New Hampshire's Division of Homeland Security and Emergency Management, as well as the U.S. Secretary of Energy, the Federal Energy Regulatory Commission, and ISO New England. Data submitted by utilities under the law is protected as critical energy infrastructure information and exempt from public disclosure. The bill's fiscal note estimates the investigation will cost up to $350,000, funded through a special assessment on electric utilities under RSA 363-A rather than direct state appropriation.
The law's findings section cites extra-high-voltage transformers, those rated between 345 kV and 765 kV, as the grid equipment most vulnerable to these currents and the most difficult to replace, with manufacturing lead times of four to six years.
