How Is Food Waste Converted Into Energy?

Food waste is one of the biggest problems we can tackle at home. Reducing how much food we prepare and reusing leftovers for other meals are just the start. If you’re putting food waste in the bin, it’s just getting sent to landfill.

Food waste can be converted into energy for our gardens and plants, and some scientists are even looking into how food waste can be turned into electricity on an industrial scale.

We can convert food waste into energy at home by composting – this breaks down the food and creates nutrient-rich compost for our plants. Even if you don’t have a garden you can still join the compost movement with bokashi fermentation or vermicomposting!

How is food waste converted into energy at home?

Food waste can be used to generate energy in the form of electricity or heat. Converting waste into energy at home is a form of waste recovery because by making energy from the waste we’re preventing that waste from being disposed of.

Waste recovery comes after prevention, minimization, and recycling of waste. It’s not a perfect way of dealing with waste but it does prevent waste from going to landfill.

The ways of generating energy from waste include combustion, gasification, and anaerobic digestion.

Combustion converts waste into heat by burning the waste. This can drive a turbine to generate electricity. However, combustion produces emissions so it’s important to be careful what you’re burning.

Gasification involves generating gas from waste by combining the waste with oxygen and steam, which can create fertilizers or generate electricity.

Anaerobic digestion generates energy from organic waste to create biogas and fertilizer. This is one of the most popular forms of home waste recovery because it’s a form of composting!

As you can see, most ways of converting waste into energy don’t actually generate electricity, because the best ways of waste recovery at home generate heat or a helpful byproduct like fertilizer.

Unfortunately, turning waste into energy at home is pretty difficult without the right equipment or the right kind of waste. This is why composting is one of the easiest ways of converting organic waste like food and garden waste into something useful.

Can we turn food waste into energy?

Food waste can be turned into energy either at home or through industrial processes.

In Scotland, food waste collections take food waste to anaerobic digestion facilities where microorganisms are used to break down the waste. As it breaks down, methane is released which is collected and converted into biogas, which then generates energy.

This would be pretty hard for anybody to do at home without the right equipment, but there are still ways of turning food waste into energy.

Turning food waste into compost is a form of waste recovery, but it doesn’t necessarily make energy. The heat generated in a compost heap is a form of energy, but extracting the heat is pretty difficult!

But does that mean composting isn’t worth it? Definitely not!

Can food waste be used for energy?

Food waste can be used for energy, but the way of extracting that energy is largely impossible for the average homeowner. Instead, you’d have to check local government and programs that can collect your food waste for you.

If you live in an area that will take your food waste and use it to create energy, you should sign up right away. Any renewable source of energy is worth it!

Anaerobic digestion doesn’t just create biogas either. Another byproduct is digested, the solid waste left behind, which can be used as a fertilizer.

For everyone who doesn’t have access to these programs, you can still use your food waste to create energy for your garden and the environment. Composting food waste enables you to transfer the remaining nutrients into the ground again, which can have a major impact on your local ecosystem.

How to turn food waste into energy at home

There are two main ways of turning food waste into energy at home: composting and bokashi fermentation.

Compost heaps are easy to make and can even be shared with your neighborhood, helping more people make a major change. If you have a community garden or a lot of eco-conscious neighbors, setting up a communal compost heap will help every member who uses it.

Not only will the compost heap be added to by multiple households but the compost will also be used for more gardens.

However, if you just want to compost your own waste and add it to your own garden, all you need is a space at the bottom of your yard or a compost bin.

A compost bin or container is good for making sure that no rodents or local wildlife are attracted to the smell of the compost, but an open compost heap could benefit your local environment by providing refuge and feeding to a wide variety of wildlife.

Hedgehogs, small mammals, bats, birds, grass snakes, toads, beetles, and slowworms all benefit from having access to an open compost heap. Even better, they act as natural pest controllers by eating the insects and slugs surrounding the heap.

Bokashi fermentation, also known as bokashi composting, is another way of turning food waste into energy for your plants. You can do bokashi fermentation even if you don’t have a garden.

While bokashi fermentation doesn’t create compost straight away, the pre-compost it produces means you can go out and bury it in the soil to give more nutrients to the surrounding soil. This is perfect if you have an allotment or a small garden, and you could even use this for adding extra nutrients to a patch of your local environment.

As well as pre-compost, bokashi fermentation also produces “bokashi tea”. This liquid needs to be drained from the bokashi bin but can be added directly to your indoor plants, garden, or local environment.

What kitchen waste can you compost?

Knowing what kitchen waste you can add to your compost is important, especially because composting and fermentation can handle different amounts of waste.

Compost heaps can handle a lot of different waste, and it’s important to make sure that you put both carbon and nitrogen sources in your compost. Ideally, a ratio of 30:1 carbon-to-nitrogen will benefit plants the most, but even a 50/50 mix of carbon and nitrogen sources will compost.

Carbon sources of waste:

Nitrogen sources of waste:

  • Coffee grounds
  • Grass
  • Stale bread
  • Vegetable scraps

What to be careful about composting:

What not to compost:

  • Bones
  • Grease and oils
  • Pet waste
  • Treated sawdust

For bokashi fermentation, check out this table of what you can put in the bokashi bin:

What you CAN put in your bokashi bin: What you CAN’T put in your bokashi bin:
  • Bread, cake, and crackers
  • Coffee grounds and tea leaves or paper tea bags
  • Cooked or uncooked meat and fish
  • Dairy products like cheese
  • Eggs and eggshells
  • Fresh fruit and vegetables
  • Peelings, skins, salads, and cores
  • Small bits of wood, including toothpicks
  • Vegetation like flowers and leaves
  • Chemicals
  • Glass or synthetic materials
  • Liquids like grease and oil
  • Moldy or rotten food
  • Plastic (including plastic wrap)
  • Shellfish shells
  • Soup


It’s always best to check online before composting or fermenting something new.

If you’re interested in vermicomposting, you should be even more careful about what food waste you’re feeding the worms, as some can be poisonous or otherwise harm the worms.

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