Challenges related to approximating the energy consumption of a website

Based on a rough estimate, the ICT industry consumes 7 to 10% of the world’s energy, and around 70% of this is related to usage while the rest can be considered embodied due to manufacturing, logistics, and related activities. Simultaneously, the web has become an important channel for consuming ICT services as it is the largest available application platform globally. Especially energy consumption of mobile web applications has been studied in detail, but there is a clear research gap for web applications because suitable measurement tooling has not been available earlier. The purpose of this article is to review the current state of the art and understand how to approximate the energy consumption of web applications effectively by measuring an existing website that has been implemented with two different web frameworks—Qwik and Next.js. Our main findings indicate that although services that approximate energy consumption of web applications exist, they tend to overestimate consumption when compared to our measurements and they may even show contradictory results between different web frameworks. Further, we found that Firefox Profiler can be used to measure energy consumption with high precision. We also found that Website Carbon service fails to acknowledge techniques, such as lazy rendering, and there were open questions related to hosting detection (green or not) while the service was not transparent in calculating the results—not disclosing intermediary results or exposing the scope of the calculation. Our key recommendation is to use CPU-based measurement methods in estimating web energy consumption.