Biogas digester update

Biogas digester unit 2.0 – performance update

We’ve been using our biogas digester from HomeBiogas for two years now, and think it’s time for a performance update.

You might know that we started out with the first generation biogas digester HomeBiogas brought on the market. Click here to read the blog post. We were very excited about the idea of producing our own cooking gas from food scraps because it completes our off-grid setup. So how does it?

“Bacteria break down organic waste in a naturally occurring process, and HomeBiogas stores and harnesses the energy created so that you can use it.”

I found this explanation on HomeBiogas’ website. It’s a very short and high-level explanation but essentially this is what happens. Microorganisms break down organic matter (food scraps) in the absence of oxygen (anaerobic digestion). The result is biogas and a liquid fertilizer concentrate which can be used on the garden. For a more detailed description click here to read our first post about activating the biogas digester.

When it comes to feeding the digester, you can add up to 6L of food scraps per day for 2 hours of cooking gas in return. We usually add less and still have enough gas.

Going full circle

For us, it’s the best way of getting rid of food scraps and toilet waste. Yes, that’s right, we’re going full circle. The digester breaks down our toilet waste, produces gas from it and we use it to cook our meals. This cycle repeats itself on a daily basis. We think this is really cool and one of the most sustainable ways of dealing with toilet waste.

Performance review

Anyway, I’m getting off-topic and will just say it straight up: we LOVE our biogas digester. When it comes to rating our biogas digester on a scale from 1 to 10, we would give it a 10 out of 10. This is just the most amazing product and every household should have one. We are very pleased with its performance as we always have enough gas to cook a meal or two per day plus coffees and boil water for tea.

So far, we rarely ran out of gas. The only times when we are low on gas or ran out are when temperatures drop below 20 degrees Celcius for a number of consecutive days or when we intentionally use it up.

Warm climate

The digester performs best in temperatures above 25 degrees Celcius. So in our subtropical summer, we can’t use up the gas fast enough. Gas production definitely slows down in winter when temperatures drop down to 10 degrees. However, since the sun is out on most days the digester sill generates gas but at a slower pace. HomeBiogas recommends adding a water heater if temperatures drop below 20 degrees or stop feeding the digester at all.

To sum it up, in a warm subtropical climate like ours, the biogas digester produces all-year-round.

Feeding the digester

What kind of “food” does the digester like? HomeBiogas recommends to only feed it kitchen waste and manure and to avoid things like paper, sand, plastic, leaves, branches, straw, dirt, large quantities of citrus peels or cooking oil.

On a daily basis, we feed the digester 1 or 2 litres of food scraps in addition to our and the cats’ toilet waste. Sometimes we only feed it our toilet waste and the digester still produces incredible amounts of gas. It’s so cool.

I’m having a hard time coming up with cons since everything is so easy and simply works. The digester is easy to set up and requires very little maintenance (except for emptying it every two years). I’m not sure how well or if the digester performs in colder climates. Potentially, it might be more suitable for warmer climates. It would be interesting to find out though, so please leave a comment if you have experience with this.

Conclusion

We are very happy with our biogas digester and wouldn’t want to live without it. The unit is very handy and useful. It’s a great way of putting kitchen waste to good use. We can only recommend it.

By the way, HomeBiogas does not pay or sponsor us … although they probably should. Lol.

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9 thoughts on “Biogas digester unit 2.0 – performance update

  1. Interestingly the latest units are being sent with heaters as part of the package so I guess they’re pre empting problems there.

    1. Graham, I think it would but also think we still need to look at rules and regulations of having methane gas indoors. This is something we are gonna need to push

    2. Hi Graham, this is one of the methods Homebiogas suggests for cooler climates besides the water heater. Visit their website for more information.

  2. Hi Paul & Annette, thanks for the update on the Home Biogas 2 – it’s amazing! Question on how you use the methane gas in your kitchen, did you need to buy a specific methane gas suitable range? I saw in your video that you have 2 gas burners and 2 induction burners. Looks like you’ve installed your own double gas burner instead of the single burner that Home Biogas provides.

    Any info you can share on the differences between methane and LPG burners (cost, availability, manufacturers, etc.) would be appreciated. Home Biogas is the future!

  3. What an amazing product!
    I’m in the process of researching to build my own tiny house and was amazed that I could use this option instead of a composting toilet and create my own energy. Because I will be in a similar situation to yours and using the toilet system with human waste can you let me know what you do with the liquid fertiliser, is it still suitable to be put on plants ?

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