A commitment to a low-carbon future

Black Pepper engaged with the UK's largest producer of low-carbon electricity, to create a responsive web app that helps to explain the very complex domain of energy production of the future.

The UK's energy comes from both renewable (wind, solar) and non-renewable (coal, gas) sources, as well as nuclear and storage. However, this is all due to change in 2050, when the UK has committed to becoming a 'net-zero' emitter.

What does 'net-zero' mean?

Net-zero refers to achieving a balance between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere. There are two different routes to achieving net-zero, which work in tandem: reducing existing emissions and actively eliminating greenhouse gases.

A gross-zero target would mean reducing all emissions to zero. Gross-zero is not realistic, so instead the net-zero goal recognises that there will be some emissions. However, any emissions need offsetting through natural carbon sinks, such as oceans and forests.

When the number of carbon emissions produced is cancelled out by the amount removed, the UK will be a net-zero emitter. The lower the emissions, the easier this becomes.

Our challenge

Due to unpredictable weather conditions, renewable energy alone does not provide electricity reliably enough to meet the UK's demand. It's possible to achieve a net-zero outcome but, only by utilising a wide range of energy sources, including nuclear and storage in the energy mix.

How do we explain the complexity of creating the right energy mix and educate users, who have very little or no knowledge of energy production, in a simple web app?

Our research-led human-centred strategy

User Research and Insights

  • Conduct stakeholder research to gain a deeper understanding of the complex domain
  • Rapid prototyping and testing, to quickly validate any assumptions about the field and users knowledge of it

UI Design and Development

  • Design an engaging and informative, yet simple user interface, using the minimum amount of information required to get the message across
  • Build a responsive user interface allowing users to interact from any regular device


  • User research
  • UX design
  • Responsive UI design
  • Data analysis
  • Bespoke software development


  • React
  • AWS
  • CI/CD

Research-led, human-centred software development approach

Phase 1

Due to the complexity of the domain, our priority in the first instance was to ensure all team members gained a deeper understanding of how energy is generated, what impact the weather has on this and what the implications of net-zero mean for the future of energy production. Black Pepper undertook a period of discovery, which included facilitating some key stakeholder workshops.

The output from these workshops included an initial data model and some UI wireframes, which were later used to create a prototype for usability testing.

Energy mixer sketch
Energy Mixer sketch
Energymixer phase1 2
Energy Mixer version 1

We worked in collaboration with the client, to design and test an initial prototype that could be used to validate some assumptions we’d had to make. The testing, with a few hundred users, was invaluable and confirmed some concerns we’d raised. The data model was too simple and didn’t contain enough information to explain to users why their energy mix wouldn’t work in certain situations. Based on feedback, we enhanced the prototype design and proposed a new data model that would answer the questions that users were asking, as well as present the complex data in an easy to understand way.

Chris McCourt
Head of User Experience, Black Pepper Software

Phase 2

Based on the new data model and user feedback, we further enhanced the user interface to answer the questions that had arisen during user testing.

The result was a more informative display. Users with no knowledge of how energy production works could now create an energy mix. And, based on typical weather conditions, understand how each energy source contributes to powering the UK and keeping all our lights on.

The findings from the initial round of user testing meant quite a shift in terms of how the energy mix information should be portrayed to end users. This required us to take on, and develop, a more granular and sophisticated model of the UK's energy supplies. Working closely with the client's subject matter experts, we created an easy-to-edit model to ensure all of the results were accurate and made sense, which replaced the initial model in the application.

Sam Warner
Lead Developer, Black Pepper Software
Energy mixer version 2, including demand vs production graphs, which highlight how energy production is impacted by weather conditions


So far the application has been an engaging and informative experience for 1.7k users. Initial feedback has been very positive. We're delighted to have helped our client achieve their goals of conveying complex information efficiently, through research-led, human-centred custom software development.

Create your energy mix at https://energymixer.uk

We hired Black Pepper Software because of their reputation for being a very UX-focused design agency. They had worked with clients similar to us, and they best understood our design briefs. The things that swayed me were that they agreed to the timeframes that we set, they were flexible, and they had competitive prices. They were also willing to adjust their workflow to our budget and working style. Black Pepper Software team is willing to be flexible to work within the parameters I set. They have a good process and provide great creative input. They’re a nice, friendly team.

Head of Investor Relations, European Energy Company