Renewable Energy Generation with Food Waste

  • Louh's Avatar
    Level 1
    I was reading lots about food waste over the Christmas period and didn't realise that there are over 100 operational anaerobic digestion plants in the UK that utilise food waste as fuel to produce green biogas.

    This biogas will be a substitute for natural gas (a fossil fuel) in the UK’s transition to a carbon-neutral economy.

    Interesting thought and wondering how many local councils utilise this:

  • 3 Replies

  • Best Answer

    Anasa_EONNext's Avatar
    Community Manager
    Best Answer
    Great subject.. we've also been chatting about it here at EON Next...Reducing food waste... and saving energy... Definitely an interesting one...

    The energy footprint of waste...

    When food is wasted, the resources used in these stages are squandered, and that includes unnecessary energy consumption:

    Agriculture: Growing crops, raising livestock, and using fertilisers and pesticides all require significant energy inputs. When food is wasted, these resources are lost, and the energy expended is in vain.

    Processing: Transforming raw food into the products we eat involves various energy-intensive steps, such as refrigeration, cooking, and packaging. When uneaten food is thrown away, the energy used in processing is also wasted.

    Transportation: Food travels long distances from farms to processing plants, distribution centres, and retail outlets. The transportation sector is a significant energy consumer, and food waste contributes to unnecessary fuel consumption.

    Disposal: Food waste that ends up in landfills decomposes and releases methane, a potent greenhouse gas contributing to climate change. Managing landfills also requires energy, further compounding the environmental impact of food waste. But you could use unwanted food to create your own compost for your plants (which will help cut back the energy used to manage landfills). What’s more, many local authorities collect food waste to be used in large anaerobic digestion plants to create biogas - which can be used as a renewable fuel. All you need to do is separate out your food waste at home.

    How can you help to reduce this?

    • Plan your meals properly to avoid waste - I can't count the times I've done a little too much of something and can't do anything with it
    • Store food properly
    • Always check the use by dates I think it's easy to get confused now with best before and use by
    • Learn to love left overs I know I'm guilty of throwing food away because I've not stored it properly or forgot it was there
    • Use left over as compost for your plants/fertiliser in your garden.
    • This helps reduce our energy consumption, conserve resources, and offset the environmental impacts of throwing away perfectly good food. And so help to create a more sustainable future for ourselves and future generations.

    This helps reduce our energy consumption, conserve resources, and offset the environmental impacts of throwing away perfectly good food. And so help to create a more sustainable future for ourselves and future generations.
    Last edited by Anasa_EONNext; 11-01-24 at 21:32.
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  • meldrewreborn's Avatar
    Level 91
    Better by far not to waste food at all.

    But on the news today was cases of raw butchers waste being left randomly around a town. Better to send that to foodbanks offering hot meals.
    Current Eon Next customer, ex EDF, Zog and Symbio. Don't think dual fuel saves money and don't like smart meters. Chronologically Gifted. If I offend let me know by private message, but I’ll continue to express my opinions nonetheless.
  • wizzo227's Avatar
    Level 21
    Digester methane does get made; yes, and it is done quite well here in Oxfordshire, but beware of units and scale.

    Collection takes everything weekly which households leave for the bin men in their cubic foot food waste bins. I eat my crusts and rarely buy more food than I'd eat, particularly meat and dairy, so most of my food waste is potato peelings, vegetable bits, and stuff like that which goes in the compost at home. I don't tip crumbs off the breadboard or kitchen sweepings into the bin either; crumbs and rice water go on the lawn where the birds or something can eat them.

    The digester for South Oxfordshire, which looks like three round pointy-on-top newish barns next to a building, makes enough biogas to run one generator rated at about 2MW (MegaWatts) peak. That being on the spearhead of the technology revolution to collect together most food waste instead of leaving it to fester in the same old rubbish tip as smelly old shoes and common rubbish, they did not get the extra machine to separate out pure methane from the biogas mixture of carbon dioxide water and methane (and a bad smell) which you get straight out of digesters, and opted instead to get the right sized engine to burn it off instead and sell electricity. Were another to be made somewhere else, they would now have the engineering numbers to design and build the right separator to inject pure methane directly into the town gas mains.

    One should still be cautiously optimistic and not get overexcited. I don't know the efficiency of that generator but suppose that methane worth up to 5 MegaWatts (thermal) came out of a food waste processor, was liquified and cooled, and siloed in a cold tank until the next evening peak of gas demand. That could continually only provide gas for 320 gas boilers similar to my combi gas boiler doing central heat or 160 of them while running on the hot water boosted configuration. Bottling and keeping the biogas methane for the most urgent times in every day, that is still only going to provide hot showers and gas central heating for about ten thousand people (at 12kWh per person per day; 1.1 cubic metre old gasmeter units); not the hundred thousand or so whose food waste was collected. So digesters are a genuine contribution, not a full solution to energy provision. Somebody wrote that their house needs 100kWh per day to heat at this time of year. Please could moderators reply with better figures as get used in gas network planning or with January averages known in the call centre?

    What I think is needed is to look at the map and the pipelines, to decide the right decommissioning date for household gas, whole towns at a time. Electricity upgrades for those towns need to be planned and operational, and households need to know the date in order to properly plan their capex on such major purchases as rooftop solar and boiler replacement. North Sea production is still above 40% of its peak, so there are plenty of towns which should remain on the gas pipelines after 2024. It might be sensible to site food digesters to be moving biogas towards those places which will stay on the gas network.
    Last edited by wizzo227; 10-01-24 at 19:05. Reason: spelling biogas