Biogas in cool climates

So, I’ve looked through a bunch of posts about biogas and am a bit bummed to see a bunch of them are several years old and have no responses. But I’ll attribute that to the fact that these systems are relatively new and not widely used, at least thats my take on it.

I’ve been thinking a lot about turning our kitchen scraps, chicken manure and bedding and our own manure into a safe fertilizer and energy source and biogas seems to be what I’m describing. I know little about it though, and from my reading, it sounds like it may not be very practical in cooler climates due to needing to be around 68 degrees Fahrenheit to work well. We live in upper Michigan and get real winters here, so maintaining that temperature is only realistic for half the year at best, with a greenhouse and full sun.

Here’s my idea:

Get a home biogas setup and feed it everything we can. Locate it in full sun and in some sort of a greenhouse to capture more heat. Produce an abundance of gas during the warmer months and store it in propane tanks or something similar. When winter comes, the digester can go dormant and we can use up our stored gas.

Is this at all feasible, or not? There’s so much I dont know, like:

-can biogas be piped into storage tanks for long term storage?

-can biogas be condensed similarly to liquid propane?

-can biogas be used with existing propane fueled appliances, or do special appliances need to be purchased?

-will a small family with a small flock of chickens really produce enough to feed the digester and make enough gas to be of use for daily cooking or heating water in the winter?

-are there likely state or local laws preventing these sorts of setups?

Anyone who knows these things or has experience, please chime in!

Thank you,
-Brody

My understanting is that the gas from a digester will be methane with a high moisture content. Methane does not liquify except at extreme cold temperatures. Any storage system would be very large. Methane contains substantially less energy per volume, so propane appliances would run much cooler unless modified. It's still a really cool idea, but if storage is required I'm not sure it's practical.

John C Daley wrote:Look at this for a start

That was helpful. I emailed MyGug to get more information on their products. Thanks!

Douglas Alpenstock wrote:My understanting is that the gas from a digester will be methane with a high moisture content. Methane does not liquify except at extreme cold temperatures. Any storage system would be very large. Methane contains substantially less energy per volume, so propane appliances would run much cooler unless modified. It's still a really cool idea, but if storage is required I'm not sure it's practical.

Yea, my understanding is similar to yours. As of now, it seems like home scale biogas, especially in cool climates, just really isn’t that productive, convenient, efficient or practical. I hope that with technological advancements that changes. And I suppose either way, communities and municipalities could start using digesters since it would be larger scale.

Hi, I'm at 61°N in Finland and I have a DIY biogas digester based on the SolarC³ITIES IBC design. It's part of my diploma in applied permaculture design. You can read about it: https://www.beyondbuckthorns.com/content/dapd/introducing-jean-luc

-can biogas be piped into storage tanks for long term storage?

storage at the DIY scale is usually done in floating drums or storage bags. You can compress it - if you can get rid of the CO2

-can biogas be condensed similarly to liquid propane?

not on a DIY scale. At least not that I'm aware of.

-can biogas be used with existing propane fueled appliances, or do special appliances need to be purchased?

no. Methane needs a different air to fuel ratio - and biogas out of a DIY digester is without pressure. You can modify the stoves. There are videos on Youtube.

-will a small family with a small flock of chickens really produce enough to feed the digester and make enough gas to be of use for daily cooking or heating water in the winter?

depends. Temperature inside the digester should be at least at 20°C to get it going. 37°C is preferred. If you can get it up to that temperature it depends on the size of your digester. Let's say you have one cubic IBC, then you feed about 15kg of food scraps per day to get about 1m³ of gas.  

-are there likely state or local laws preventing these sorts of setups?

If have no idea about regulations in the US...

The United Nations site has some decent information.

research report on improving cold temperature biogas digestion
https://www.solarcities.eu/sites/solarcities.eu/files/documents/2014_09_29_kateywalteranthony_finalreport1.pdf