A double-decker electric bus (No. 23 route) caught fire at the Westbourne Park bus depot/garage on Great Western Road while stationary and unoccupied. No injuries were reported.

Four fire engines and around 25 firefighters from London Fire Brigade responded; the fire was brought under control within about 45 minutes. The bus was destroyed, along with two electric vehicle charging points.

It happened on one of the hottest days of the year in the UK (record June temperatures, with parts of London exceeding 35°C amid a heatwave). Thick black smoke was visible from the nearby A40 Westway flyover.

As of June 26, the London Fire Brigade’s investigation team has not released a cause. Possible factors under review likely include:

• Battery thermal runaway — Lithium-ion batteries can enter a self-sustaining exothermic reaction if a cell overheats, is damaged, overcharged, or has manufacturing defects. Ambient heat can contribute by raising baseline temperatures, reducing the margin to critical thresholds (SEI decomposition ~80°C, electrolyte breakdown higher).
• Charging-related issues (the bus was at a depot with chargers damaged).
• Maintenance, battery age/degradation, or electrical faults.
• Coincidence with extreme heat (London hit record June temperatures, ~35–36°C).

No evidence yet confirms the heatwave as the direct trigger, but high temperatures stress battery thermal management systems, especially if cooling (active or passive) is strained while parked/charging. EV batteries have sophisticated cooling, but depots during heatwaves test those limits.

London has one of Europe’s largest electric bus fleets: over 3,000 zero-emission buses (battery electric dominant) out of ~8,800 total, with ambitions for a fully zero-emission fleet by ~2030–2034. TfL and operators like First Bus and Go-Ahead have expanded rapidly.

Prior incidents:

• January 2024: Wimbledon route fire led to temporary withdrawal of a specific fleet type for investigation.
• 2022: Potters Bar depot fire damaged multiple buses, prompting recalls.
• These are notable but not daily occurrences. Investigations often lead to software updates, battery checks, or design tweaks rather than halting rollout.

Electric bus fires are statistically rarer than diesel bus fires.

Global data (2010 onward) shows low rates for e-buses relative to fleet size (estimates ~0.008–0.015 fires per 1,000 e-buses/year vs. much higher for diesel). Diesel vehicles overall have far more fires due to fuel leaks, oil, etc.

However:

• When EV/battery fires occur, they can be more intense, harder to extinguish (require massive water volumes or special agents), and produce dense smoke.
• Media amplifies them because the technology is pushed as the future, making failures politically/symbolically charged amid net-zero policies.
• Heatwaves, cold weather (reduced range), and rapid charging add real engineering challenges that diesel buses handle more forgivingly.

Public reaction on X and media (GB News, Telegraph, etc.) highlights skepticism: “Useless in winter, catch fire in summer.” This fits broader debates on forced electrification timelines vs. resilience.

Safety/Engineering:

Batteries have improved with better chemistries (e.g., LFP more stable than NMC), thermal barriers, and BMS (battery management systems). But scaling fleets quickly can surface edge cases like depot charging in extremes. Expect post-incident reviews on charging protocols during heat alerts.

Reliability & Policy:

London’s push is ambitious; incidents risk service disruptions and higher insurance/maintenance costs. Critics argue diesel/hybrids offer better all-weather reliability until battery tech matures further.

Risk Perspective:

One bus fire in a large fleet during a record heatwave is not systemic proof against EVs, but ignoring patterns (prior London fires, global thermal runaway cases) would be unwise. Investigations matter more than narratives.

Practical Trade-offs:

EVs excel in zero tailpipe emissions and quiet operation for urban air quality. They face challenges in energy density, charging infrastructure, and extreme conditions compared to mature ICE tech.

Media coverage (BBC, Independent, Telegraph, GB News, etc.) and social media have highlighted the timing during the heatwave, with some commentary questioning EV suitability in extreme temperatures. However, as of now, it’s one specific depot fire rather than a widespread issue.

Electric vehicle fires (often involving lithium-ion batteries) can be intense and harder to extinguish once thermal runaway starts, but they are statistically rare compared to internal combustion engine vehicle fires. Investigations will likely focus on battery condition, charging equipment, maintenance, and environmental factors.

This is a serious but isolated (so far) event under investigation. It underscores the need for robust testing in real-world UK conditions (heatwaves are rare but increasingly discussed).

Rapid decarbonization has benefits and risks — balancing them requires transparent data, not rushed mandates or denial of problems.

Future updates from LFB/TfL on the root cause will clarify if heat was a contributing factor.