Our electricity fuel mix
As you may know, 100% of our electricity comes from renewable sources, and every year we need to let the regulator know where this comes from. Alongside every unit of renewable electricity we purchase is a snazzily named Renewable Energy Guarantee of Origin (REGO) certificate. These certificates allow Ofgem to verify the source of every supplier's electricity.
10% of Bulb's gas is renewable, compared to 0.3% national average
Note: Based on Digest of United Kingdom Energy Statistics 2017
Source: Department for Business, Energy & industrial Strategy
Our gas fuel mix
We also receive a certificate for each unit of green gas that we purchase. For the 10% of our gas that comes from renewable sources, we work with two certification schemes. We receive the equally snazzily named Renewable Gas Guarantee of Origin (RGGO) certificates from the Renewable Energy Association and Biomethane Certificates from Green Gas Trading.
Every carbon offset certificate we buy is verified by one of three internationally-recognised standards: the Gold Standard, the Verified Carbon Standard or the UNFCCC's Clean Development Mechanism. These organisations ensure carbon reduction projects have a robust audit trail, and that carbon savings are additional to what would happen anyway and are sustained over time.
Generating our gas
10% of the gas we supply to our members is green gas, or biomethane, which is produced by a process called anaerobic digestion. We work with independent generators who use a variety of feedstocks to produce their renewable gas:
- Purpose-grown crops: 51.8%
- Food or farm waste: 47.8%
- Animal waste: 0.4%
We like to think this gas is as natural as your uncle's after a plate of sprouts. And it's produced pretty much in the same way!
How we calculate carbon impact
Energy is all a bit abstract. It can be hard to understand the impact you have by being with a renewable supplier. To measure this impact, we compare the carbon emissions you have with Bulb to the carbon emissions you'd have if you were with a non-renewable energy supplier. That way, we can understand the impact the average Bulb member has by being with us.
To make this comparison, we need to know how much energy an average Bulb home uses in a year. In 2018, this was 4,270 kWh of electricity and 12,669 kWh of gas.
With Bulb, your annual CO2 emissions are ZERO. Because Bulb provides 100% renewable electricity and 100% carbon neutral gas, an average home with us emits 0.00 kg of CO2 per kWh of electricity and 0.00 kg of CO2 per kWh of gas. Over the whole year, this adds up to… zero kg of CO2.
With a non-renewable supplier, the average home would emit 4.2 tonnes of CO2 per year. This government report states that UK homes on the average fuel mix emit 0.283 kg of CO2 per kWh of electricity and 0.184kg per kWh of gas. Therefore, over the course of a year, a home using non-renewable energy would emit 1.2 tonnes of CO2 from its electricity usage and 2.3 tonnes of CO2 from its gas usage.
This means the average Bulb home saves 3.5 tonnes of carbon from entering the atmosphere every year. That's a lot of carbon saved. But it's hard to imagine. What does 3.5 tonnes of CO2 look like? We like to put it in context. For example, it's equivalent to the weight of an Orca. Saving that much carbon is also like planting 1,770 trees.
A recent study by the Forestry Commission showed that Kielder Forest’s 150 million trees lock up 82,000 tonnes of carbon every year. Each tree at Kielder is locking up roughly 0.546 kg of carbon per year – equivalent to 2 kg of CO2. If one tree holds 2 kg CO2 of carbon dioxide, you'd need 1,770 trees to lock up the same amount of CO2 saved by the average Bulb home.