Frequently Asked Questions

A reliable, resilient transmission grid is of vital importance to the economic and social well-being of the nation. While electric utilities have always planned for recovery from network disruptions, increased threats to the grid, both natural and man-made, have elevated the need for Grid Assurance's transformer reserve program.

The increasing frequency, likelihood and severity of these events demand that the power industry determine a path toward resiliency. Six energy companies, with geographic and technical diversity, launched Grid Assurance in 2016 to provide an industry-led grid recovery solution.

Grid Assurance offers the most robust solution in the industry.

Grid Assurance models for numerous high-impact, low-frequency (HILF) events.

Our framework considers many attributes including: the location and type of event; frequency of each event; diversity in equipment rating; severity of the event; operational spares on hand; and restoration at an agreed upon service fulfillment level.  Grid Assurance provides the modeling tools to our subscribers to execute and simulate impacts and recommendations.

Modeling helps determine the number and type of equipment a subscriber will need following a HILF event specific to their location and an agreed upon service level.

The goal is always to restore the electric grid to normality as soon as possible.

Grid Assurance provides subscribers access to long-lead-time equipment, that can it be quickly deployed, ensuring a speedy and agreed upon service level recovery of the electric grid.

Any transmission owning company looking to increase their ability to recover more quickly and fully (to an agreed upon service level) from high-impact, low-frequency (HILF) events by storing their large power transformers and other critical transmission replacement equipment in a secure, off-site location.

Operational Spares

Utilities maintain some operational spares to replace equipment that fails due to normal wear and tear. It is economically prohibitive (three to five times more expensive versus pooling costs and assets) for a utility to stockpile multiple, million-dollar pieces of equipment to prepare for full recovery following high-impact, low-frequency event (HILF) events.

Spares are often stored near the equipment they will replace which increases the likelihood the spare will also be damaged in a HILF event.


In 2006, the power sector took a critical first step to address replacement of transformers damaged by terrorist acts. The Edison Electric Institute (EEI) and several utilities formed the Spare Transformer Equipment Program (STEP).

STEP provides participating utilities the right to buy large transformers from other participating utilities, but only after a Presidentially-declared terrorist emergency.

This was a good first step. However, the struggle with mutual aid is that it breaks down when major events happen. 

The U.S. Department of Energy noted in its 2015 Quadrennial Energy Review that STEP alone is not sufficient to address large-scale grid vulnerabilities. The STEP inventory includes as-is, where-is equipment and may not be robust enough to respond to a large, coordinated attack.

Grid Assurance has secured warehouse sites across the country that provide access to rail, highway and water transportation. The sites will be close to subscribers so that equipment transportation time is reduced. The locations will remain confidential for security purposes.

Grid Assurance will store long-lead-time equipment like transformers and breakers.

Grid Assurance is not regulated by the Federal Energy Regulatory Commission (FERC), but charges cost-based subscription fees, similar to FERC-regulated transmission formula rates. These transparent, cost-based subscription fees will facilitate members' ability to recover their expenses.

Grid Assurance is an independent company offering a robust response to the numerous potential risks facing our nation's transmission system.

What People Are Saying

"Many electric power components are hand-built, manufacturing capacity is limited, and ordering them anew requires waits of up to 18 months."
— Wall Street Journal
"Collaboration is vital as we continue to address this important aspect of helping to ensure the reliability and resiliency of the nation's electricity delivery system."
— Office of Electricity Delivery & Energy Reliability RFI
"[Grid Assurance] ...will not compete with or replace STEP, but rather complement as well as supplement STEP."
— Comments filed with the Federal Electric Regulatory Commission, by the Edison Electric Institute
" important step in letting market forces solve our problems instead of pushing for federal action"
— American Enterprise Institute
"The service is a win-win; pooling assets and accessing economies of scale, which should lower costs to ratepayers."
— Homeland Security