What happens to ecommerce when the lights go out? On April 28, 2025, a massive power outage hit Spain and Portugal just before noon. We combined electricity demand data with our own data, how others experienced it and the impact of an outage on ecommerce and non-ecommerce.
The chart above from Red Eléctrica shows how electricity demand dropped sharply from 28,000 megawatts to just over 12,000 megawatts within a short time. The demand remained low throughout the day, confirming the extensive reach and duration of the outage.
Outage and internet access
The disruption in both Spain and Portugal extended far beyond the electrical grid. It severely affected internet access, e-commerce traffic, and access to vital information.
Internet progressively went from 5G to 4G then 3G then 2G then nothing at all progressively, it seems the telecom masts have a battery for just a few hours
Pieter Levels on X
The impact on ecommerce
The consequences for e-commerce were immediate and measurable. Majority of websites using RUMvision are in fact ecommerce. With our data, we could see a clear impact, just like Akamai did.
The next chart shows how web traffic from Spain and Portugal to sites using RUMvision fell dramatically during the outage:
- [A] On a regular day (April 27th and 29th), traffic dips after noon as a result of lunch time and possibly siesta
- [B] On April 28th, however, the outage happened and electricity demand dropped as of 11:33am.
Causes of electricity demand
This steep decline had several causes:
- During this power outage, internet connection started to degrade as well.
- Even if there still is internet, online shopping becomes a low priority for most people.
- And even if someone could place an order, delivery services were paralyzed. Many intersections and roundabouts in major cities were gridlocked due to non-functioning traffic lights.
€400 million up to €800 loss
In this scenario, e-commerce platforms not only lost visibility but also experienced direct revenue losses from two major European markets. In Spain alone, it resulted in approximately €400 million up to potentially €800 million loss in digital purchases according to Spain’s Minister of Economy, Trade, and Business.
When we combine the chart containing our data with the electricity demand chart from Red Eléctrica, we get the following:
Electricity and internet recovery
Eventually, internet came back between 3PM and midnight on April 28th. However, our data is showing that the outage continued to impact ecommerce traffic throughout the rest of the day and night as the result of shifted priorities, only returning to normal the following day.
Luckily, loss of traffic was not the result of the webshop nor the brand itself. As a result, power outages don't affect the customer retention in the same way as a structurally slow website does.
The impact on non ecomm
For non-commercial sites, the outage revealed vulnerabilities in how essential information is delivered to the public. Many people attempted to find updates online, but the internet was unavailable for large portions of the population. A few tried to use battery-powered HAM radios, although not all updates were being transmitted and most people simply did not own such devices.
This left millions without timely information. It also exposed a critical flaw in how most websites are built today.
We were lucky to have intermittent internet for most of the day, so we could get updates on the situation [..] It was strange having to worry about saving the phone battery
Davide Serafini on LinkedIn
CSR vs SSR
Government websites, media platforms, and emergency services should prioritize lightweight design and server-side rendering.
And there are important reasons for this approach:
- Server-side rendering allows pages to be delivered quickly, even on low-power devices or over weak connections. Combine this with server side caching on top of a CDN to get contents quicker to your visitor's device.
- Reducing reliance on JavaScript and heavy client-side logic lowers the CPU load on the user's device, improving load speed and responsiveness.
- Third-party scripts and client-side rendering can drain battery life by keeping processors active and using memory inefficiently: a major concern when users need to preserve battery during crises.
- Lighter pages with minimal code are more likely to load successfully under poor connectivity conditions, such as 2G fallback or spotty mobile coverage.
- In emergency scenarios, smartphones serve multiple roles including flashlight, radio, and communication device. Lowering battery consumption is not just a performance win: it can help people stay connected longer when it matters most.
A broader case for digital resilience
This event serves as a reminder of how dependent modern life is on uninterrupted access to power and connectivity. Even when infrastructure is partially functional, such as during a natural disaster or flood, access to reliable electricity and fast-loading websites can make a significant difference.
Core Web Vitals are not just about SEO and user experience. In moments of crisis, when mobile devices become our primary tool for information, communication, and even light, fast and efficient websites can play a critical role in both obtaining essential online information and preserving battery life.
