Website development: Faster, greener, and more responsible

As the digital world expands, so does its environmental impact. Websites, apps, and online platforms consume significant energy through data centres, network infrastructure, and the devices that access them.

While the internet often feels intangible, studies estimate that it contributes about 3.7% of global greenhouse gas emissions, which is on par with the airline industry.

The more complex and data-heavy a website is, the more energy it requires to load, process, and store. Sustainable web development focuses on reducing this environmental footprint through thoughtful design choices, optimised build techniques, and greener hosting solutions. By making conscious decisions in these areas, our developers can build websites that are more energy-efficient, faster, and ultimately more sustainable for the long term.

Sustainable Web Design Techniques

The way a website is designed significantly affects its energy consumption. From the colours and images used to how content is structured, every design choice influences how much power is required by devices to display and process web pages.

During a recent web project for Dalkia, one surprising factor in our research and discovery stage was the energy consumption in relation to choice of colours. On OLED and AMOLED screens, which are now widely used in smartphones and high-end monitors, colours are generated using red, green, and blue (RGB) light-emitting diodes (LEDs). Among these, blue requires significantly more energy than red or green because blue LEDs need a higher voltage to achieve the same level of brightness.

Within the Dalkia project design stages, a conscious decision to emphasis a warmer colour palette was made avoiding blue in the primary brand colours. According to studies, bright blue pixels can use up to 25% more power than their red or green counterparts. As a result, using dark or warm colour palettes can reduce energy consumption, particularly for mobile users who rely on battery power. Some apps and websites, including YouTube and X (formerly Twitter), have introduced dark mode options not only for user comfort but also to conserve energy.

Image optimisation

Another crucial aspect of sustainable web design is image optimisation. High-resolution images significantly contribute to data transfer and storage demands, increasing a website’s carbon footprint. Studies suggest that images account for more than 60% of a typical webpage’s total data size, meaning that optimising them can have a major impact. Using modern image formats like WebP and AVIF can reduce file sizes by 30-50% compared to traditional JPEG or PNG formats while maintaining quality.

Additionally, reducing pixel density for background images or non-essential visual elements further lowers data consumption. Within the Dalkia web design process our team applied a filter across larger banners to reduce image file size by up to 80%. Developers can also implement lazy loading, ensuring that images only load when they are about to be viewed, preventing unnecessary data transfers and saving bandwidth.

Minimising animations and video content is another effective way to make a website more energy-efficient. While motion graphics enhance user engagement, they also increase CPU and GPU usage, which drains power on both servers and end-user devices. Simple CSS animations consume less processing power than JavaScript-heavy effects, while low-frame-rate animations (30fps or lower) are more energy-efficient than high-frame-rate alternatives. In the Dalkia build, replacing autoplaying videos with interactive mouse hover play buttons made sure no bandwidth was unnecessarily used.

Efficient Build Techniques for Sustainability

Beyond design, the way a website is built and structured directly impacts its energy consumption. Optimised code, efficient asset management, and lightweight frameworks can make a significant difference.

React and Next.js are two popular frameworks that provide built-in optimisations to enhance website performance and efficiency. One of the most effective features in Next.js is automatic image optimisation through the next/image component. This feature automatically compresses and resizes images, ensuring that only the smallest possible version of an image is loaded depending on the user’s device and screen size. This results in faster load times and lower energy consumption, particularly on mobile networks where large images significantly drain battery life.

SSG & SSR

Another major advantage of using Next.js is Static Site Generation (SSG) and Server-Side Rendering (SSR). Instead of generating content dynamically for every user request, SSG pre-builds pages at compile time, reducing the need for repeated server processing. This approach lowers the number of database queries and decreases overall computational energy use. Similarly, SSR helps balance performance by rendering pages on the server rather than requiring client-side JavaScript execution, which reduces the power needed for mobile and low-end devices.

Sustainability is no longer just an afterthought in web development; it’s a core part of our strategy. By optimising images, streamlining code with Next.js, and hosting on 100% renewable energy servers, we’ve significantly reduced our build carbon footprint while improving performance. A greener web is a faster, more efficient web.

David Freshwater – Digital Director

In addition to image and content optimisation, Next.js also improves code efficiency through code splitting and tree shaking. Code splitting ensures that only the necessary JavaScript files are loaded per page, rather than loading an entire website’s scripts all at once. Tree shaking automatically removes unused code, reducing file sizes and improving page speed. Combined with automatic link prefetching, which loads resources in the background before a user clicks on them, these optimisations contribute to a more sustainable and responsive web experience.

Green Hosting: Choosing Sustainable Web Servers

Even the most optimised website requires a hosting provider, and this is where one of the biggest environmental impacts occurs. Data centres consume around 1% of the world’s total electricity, and a significant portion of this energy is used for cooling systems and redundant power supplies. Choosing a 100% green energy-powered hosting provider is one of the most impactful steps towards sustainable web development.

Several hosting companies prioritise renewable energy and carbon neutrality. Major cloud providers like Google Cloud, AWS, and Microsoft Azure have committed to carbon-neutral and renewable-powered data centres, with Google Cloud aiming to operate entirely on carbon-free energy by 2030.

Aside from choosing an eco-friendly host, reducing server requests and bandwidth usage can further improve sustainability. Content Delivery Networks (CDNs) distribute website files across multiple geographically dispersed servers, reducing the distance data has to travel and decreasing latency. This not only enhances website performance but also cuts down on the energy required for long-distance data transfers. Enabling caching is another effective strategy, as it stores frequently accessed files on users’ devices or intermediary servers, reducing the need for repeated downloads. Additionally, minimising unnecessary API calls and using efficient query languages like GraphQL helps reduce the amount of data that needs to be processed and transmitted.

A Greener Web for a Sustainable Future

The internet’s environmental footprint is growing, but by adopting sustainable design techniques, efficient build practices, and green hosting solutions, developers can significantly reduce the impact of their websites. Simple design choices, like using energy-efficient colours and optimising images, contribute to a lower carbon footprint, while leveraging Next.js and React ensures a more efficient use of server and client-side resources. Meanwhile, hosting websites on 100% renewable energy-powered servers ensures that the infrastructure behind digital platforms supports a sustainable future.

Sustainability in web development is not just about reducing energy use; it also improves performance, reduces costs, and enhances the user experience. As more companies and individuals prioritise eco-friendly digital solutions, these practices will become an essential part of building a faster, greener, and more responsible internet.

If you’d like to chat on how you can reduce your websites carbon footprint, get in touch now and make a change!