Sustainable Web Design, An Excerpt

In 1956, Roger Bannister shattered the belief that running a mile in under four minutes was impossible, demonstrating the power of breaking perceived limits. Similar to the human body's potential for speed, the internet's capabilities are expanding as standards evolve. The sustainability of websites is a growing concern, but measuring carbon emissions directly is challenging. Instead, data transfer and the carbon intensity of electricity are used as indicators. Data transfer, measured in kilowatt-hours per gigabyte (kWh/GB), is a metric for energy efficiency. Page weight, or the size of a web page, is a convenient measure of data transfer. Reducing page weight, especially for images, is crucial for lowering energy consumption. Performance budgeting, similar to speed limits, sets upper bounds for page load times and data transfer. Page weight budgets can be established based on industry benchmarks or competitor analysis. Measuring transfer size for repeat visitors provides insights into optimizing efficiency for regular users. The carbon intensity of electricity, measured in grams of CO2 per kilowatt-hour (gCO2/kWh), varies widely depending on the energy source. Choosing data centers in regions with low carbon intensity reduces emissions. Balancing carbon intensity with distance from users is essential to minimize energy consumption during data transmission. Tools are available to calculate carbon emissions based on data transfer and electricity usage.