Bulb's green gas: where it comes from and how much is renewable

Green gas is made through a process called anaerobic digestion. This uses bacteria to break down organic materials, like food or farm waste, to release biogas. Biogas is then purified and turned into biomethane, which is injected into the gas grid. Once in the grid, it’s piped into homes across the UK and used for things like heating or powering cookers.

In 2018, 51.8% of our green gas came from purpose-grown crops, 47.8% came from food waste, and just 0.4% came from animal waste like manure or slurry.

Is Bulb's green gas vegan?

0.4% of our green gas came from animal waste in 2018. That includes things like pig poo, chicken litter or turkey droppings – in other words, animal by-products. It’s the same type of waste that’s used to fertilise and grow organic vegetables. As with many life choices, being a vegan is complex, and where you draw the boundaries is very a personal decision.

We would like to see less waste produced across every industry and every area of society. We support the Anaerobic Digestion and Bioresources Association (ADBA)'s advice that while meat is still part of the UK’s diet, and the meat industry is producing waste, leaving animal by-products to decompose naturally is more environmentally harmful than turning them into something usable like green gas. Left untouched, animal waste emits methane, which is 21 times more harmful as a greenhouse gas than carbon dioxide.

How much of Bulb's gas is renewable?

The gas that Bulb supplies is 10% green, which is 30 times higher than the national average. The UK green gas industry is small, and Bulb has been growing fast. This means there simply isn’t enough green gas available in the UK to provide more than 10% to our members.

To help promote the growth of the UK green gas industry in the most sustainable way, we’ve designed a set of principles to stick by when buying our green gas.

This means we:

  • never buy green gas made from animal parts
  • buy green gas that was produced in the same year our members use it
  • enter long-term contracts with our partners (mostly 3-year contracts)
  • never buy fracked gas

The more members we have, the more viable it is to set up long-term agreements with generators to provide them with price longevity and certainty. And supply follows demand, so the more members that sign up to Bulb, the bigger the growth of green gas plants.

But green gas plants take time to build, and we’re growing fast. So there’s a lag between how much we need to buy, and how much green gas there is available. We watch the market closely and will increase the percentage of our green gas as soon as we can.

Because we can’t currently provide our members with 100% green gas, we take responsibility for the carbon emissions from the 90% of our gas that isn’t green by partnering with carbon offset projects around the world. This makes our gas 100% carbon neutral.

Will you always be able to provide 10% green gas?

We’ll always provide 10% green gas where we can. The green gas market has grown fourfold since Bulb started in 2015, but Bulb is growing much faster. We’re constantly looking at the way the market is evolving – but it’s slow moving. It takes a long time to build a green gas plant. Even if dozens of developers decided to build new plants tomorrow, it would take a few years to see a significant increase of renewable gas in the grid.

Suppliers like Bulb provide important income for generators, but their main income still comes from the Renewable Heat Incentive (RHI), a government subsidy. There’s no clarity from government yet on what will happen after 2021 when this incentive might be withdrawn. This means that the future of the industry is uncertain. It’s crucial for the government to confirm what will happen to the RHI after 2021.

The cost of new green gas generation hasn’t come down enough to create a reliable market yet. We’ve done the maths and without subsidy, suppliers (and ultimately customers) would have to pay about £850 extra per customer a year for 100% green gas.

So no promises, but we’ll do our best. We will always provide 100% carbon neutral gas, but ultimately we will have to wait to see what the green gas market does.

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