Your Solar Annual Wrap includes an estimate of how much CO₂ emissions your system has helped avoid.

This is based on a simple principle: every kilowatt-hour generated by your solar panels is electricity that does not need to be produced by the national grid, which includes the burning of fossil fuels.

To calculate this, we follow these steps:

1. Measure your actual solar generation
   ‍We use your recorded kilowatt-hours (kWh) over the year. This is the clean energy your system produced on site.
2. Apply the official UK grid emissions factor
   ‍Each kWh of grid electricity has an associated carbon intensity. We use the latest government-published emissions factors for electricity. These factors reflect how much CO₂ the average grid-supplied kWh would have produced.‍
3. Calculate avoided emissions
   Solar generation (kWh) × grid emissions factor (kg CO₂/kWh) gives the total kilograms of CO₂ avoided.

We convert this into tonnes of CO₂ to match standard reporting formats.

Data source: Official UK Grid emissions factors

To make the environmental impact more relatable, your Solar Annual Wrap includes a fun comparison: how many cups of tea your solar energy could have brewed over the year.

This is based on the typical amount of electricity needed to boil water in a standard kettle.

Here’s how we calculate it:

1. Start with your annual solar generation
   ‍We take the total kilowatt-hours (kWh) your system produced during the year.
2. Use a standard energy-per-boil assumption
   We used the following assumptions:
   
   • One cup = 300 mL of water (0.3 kg)
   • Temperature rise ≈ 15 °C → 100 °C = 85 °C
   • Specific heat of water = 4186 J/kg·°C
   • 1 kWh = 3,600,000 J
   • This would give a theoretic energy demand for brewing at 29.6 Wh per cup‍
3. Considering real-world efficiency loss
   In practice, boiling water often requires more energy. Kettles have varying efficiency, people may fill larger cups, and winter room temperatures can be lower than 15 °C. These factors mean the actual energy requirement is typically higher than the theoretical minimum.
4. Estimate number of cups
   Total solar Wh ÷ 45 Wh gives the approximate number of cups of tea your solar energy could heat.

This gives a more physics-based, accurate estimate while keeping the comparison fun, simple and relatable for clients.

When calculating your CO₂ emissions reduction, we reference the official UK grid carbon intensity published in government statistics.

This value represents how much carbon is emitted, on average, for every kilowatt-hour (kWh) of electricity supplied by the national grid.

The UK grid has become continuously cleaner in recent years.

1. In 2020 The grid carbon intensity was 0.25091 kg CO₂ per kWh.
2. By 2025 This value has fallen to 0.19323 kg CO₂ per kWh.

This is a reduction of around 23% in carbon intensity.

The change reflects the ongoing decarbonisation of the national electricity system due to increased renewable generation, improved grid efficiency and reduced reliance on coal and gas.

Data source: Official UK Grid emissions factors

This helps you see when conditions were most favourable for solar generation and gives you a quick sense of your system’s peak output.

Here’s how we calculate it:

1. Gather your generation data ever 15 minutes
   ‍We begin by collecting your recorded solar generation and grouping into daily totals. This tells us how many kilowatt-hours (kWh) your system produced each day.
2. Data Cleansing
   Raw data often contains gaps or irregularities caused by internet dropouts, temporary system faults or communication issues. We run automated checks to detect missing intervals, remove noises, and correct invalid readings.
3. Identify the highest-production day and week
   Once the dataset is validated, we calculate the total energy generated each day and each calendar week.
   • The day with the highest total becomes your Most Productive Day
   • The week with the highest combined generation becomes your Most Productive Week