Why BESS insurers are sweating transformers and contractor errors over battery fires

<p class="p1"><span class="s1">The BESS insurance risk profile is shifting. In an exclusive interview, Tokio Marine GX underwriter Michael Carrington explains why insurers are looking past battery fires and sweating over supply chain bottlenecks, high-voltage transformers, and costly EPC integration errors.</span></p><p><strong>From <a href="https://www.ess-news.com/2026/03/20/why-bess-insurers-are-sweating-transformers-and-contractor-errors-over-battery-fires/" rel="noopener" target="_blank">ESS News</a></strong></p>
<p>For underwriters insuring gigawatt-scale battery energy storage systems (BESS), thermal runaway is no longer the only bogeyman. It’s the velocity of product development, inexperienced integration, and vulnerabilities in the balance of plant that are keeping the insurance industry on its toes.</p>
<p>Michael Carrington, an underwriter at renewables insurance specialist TMGX, noted to <strong>ESS News</strong> that the industry is iterating faster than insurers can build historical models.</p>
<p>“The launch of the very first Megapack in 2019 was a 3 MWh enclosure,” Carrington says. “Moving to the last year, high-end products such as <a href="https://www.ess-news.com/2025/09/19/byd-unveils-worlds-largest-14-5-mwh-dc-energy-storage-system/">BYD’s HaoHan are touching 14.5MWh</a>. In that very short timeframe, we’ve seen almost a 500% increase in megawatt-hours per enclosure.”</p>
<p><em>To continue reading, please visit our <a href="https://www.ess-news.com/2026/03/20/why-bess-insurers-are-sweating-transformers-and-contractor-errors-over-battery-fires/" rel="noopener" target="_blank">ESS News website</a>.</em></p>