How Bulb buys its electricity

Bulb supplies 100% renewable electricity to all its members from solar, wind and hydro. You can find out about the generators we work with by exploring our generator map. Every unit of electricity we supply can be traced back to a renewable source. There are different ways to buy this renewable electricity, and at Bulb, we buy it in 2 different ways:

The exact amount of electricity we buy in each way varies over time. This is because it depends on how windy or sunny it is (compared to how windy and sunny we thought it would be), and on our members’ actual energy usage (compared to what we forecasted it to be). 

We have enough PPAs with renewable generators to meet up to 40% of our members’ demand. We could reach this percentage on a windy day when our members’ demand is low. But the percentage could be a lot lower on a still day, when our members are using a lot of electricity.

Power Purchase Agreements (PPAs)

We have several long term contracts with renewable generators across the UK to directly purchase the electricity they produce. Alongside each unit of power we buy from them, we buy a REGO certificate to verify it was from a renewable source.

Renewable Energy Guarantee of Origin certificates (REGOs)

The electricity we don’t buy through direct contracts with generators, we buy on the wholesale market. And for every unit of that, we also buy a REGO certificate to match. Renewable generators are awarded REGO certificates from Ofgem, the energy regulator. They receive one certificate per megawatt hour (MWh) of renewable electricity generated. By matching the electricity we buy with REGOs, we ensure that every unit of electricity that we supply can be traced back to a renewable source.

We do this ‘matching’ monthly. Every month, we buy REGOs to match the electricity our members have used in that month. For example, if our members use 400 gigawatt hours (GWh) of electricity in a month, we'll:

  • buy that electricity on the wholesale market
  • match the quantity with REGOs from renewable generation put onto the grid in the same month

Doing this means that whenever we buy electricity from the wholesale market, the REGOs that we’ve bought along with it closely represent the renewable power that’s available in the grid at that time.

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