eli5 Could we replace normal gas with biogas?


I was watching a video about New York sewage water systems and how they extract biogas from the waste to power nearby buildings? If we would invest more money on to that kind of system, could it replace natural gas demand that there is (example in Germany)?

Sorry my English, not a native speaker.

In: 2

Yes we could actually, but not as a “Fix everything” solution.

The biggest sources of biogas would be human waste, animal farts/burps/waste, and landfills.

Interestingly, the methane produced from these sources is a MASSIVE PROBLEM, as methane is a powerful greenhouse gas. You might have noticed those tall towers at various fuel plants and such just burning like a candle? That’s just them burning off the waste methane (turning it to CO2 and Water) to prevent it from escaping and contributing to greenhouse gas emissions. (Methane is many times more potent as a greenhouse has than CO2).

So what people are doing is capturing escaping methane from sewage treatment, animal processing facilities and landfills and yes, they are finding ways to generate power locally, like powering the farm the cows live on or nearby buildings.

I think ultimately, it’s hard to do because those facilities are really *large* so you’d need a massive system to collect the gas, store it, transport it, etc. And in the end you basically just have a moderately polluting fuel that can be produced cheaper and easier via fossil fuel production.

I think the consensus is that, both in terms of cost, development time, effort, etc. would be better to find ways to reduce the production of biogas directly (different feed for cows, compost in lieu of landfills, etc) and switch away from combustible fossil fuels and go either nuclear or renewable for our energy needs.

Yes and no.

It can and is done [https://www.cleanenergywire.org/dossiers/bioenergy-germany](https://www.cleanenergywire.org/dossiers/bioenergy-germany) German is the world’s latest producer of biogas and have around 8700 plants that make it

The amount that is produced today is “28.8 million m3 per year of raw biogas is
generated and fed into the gas grid.” according to [https://www.worldbiogasassociation.org/wp-content/uploads/2019/09/WBA-Germany-4ppa4_.pdf](https://www.worldbiogasassociation.org/wp-content/uploads/2019/09/WBA-Germany-4ppa4_.pdf)

Compare that to consumption of 2,872,840 million cubic feet =81,383 million cubv meter[https://www.worldometers.info/gas/germany-natural-gas/](https://www.worldometers.info/gas/germany-natural-gas/)

So the production needs to be 2800x larger to replace all-natural gas.

So biogas can and is produced and added to the gas grid. The prob

Theoretically yes. Practically probably…

I am danish and in Denmark we are currently building more and more facilities for biogas production of food waste and farm waste.

In a country like Denmark you can build 1 facility in circles of 20km radius (except around the cities) and supply them with farm waste (mainly animal manure but also straws etc). This will produce a large over capacity for Denmark on biogas, to be sold to other countries in need (Norway and Sweden have much less farmland and much more forest)

The biogas typically contains methane (the gas we need), 20-40% CO2 and small traces of sulfor. But less sulfor than fossil natural gas. And the CO2 can be fused with hydrogen (produced ie by excess wind/solar power and seawater) to make methane and a very clean gas for burning and storage. In Denmark we already have great pipe transport system and underground storage facilities for natural gas. And power and heat production from gas engines and boilers, meaning it could be a smooth transition.

For the general green energy needed for year round supply including what is needed for hydrogen production, different output due to wind/sun etc you would probably need around 400% capacity compared to peak usage. But then when there is no sun and wind, the biogas can be burned in already existing or retrofitted facilities for stable power supply

I am just a laiman and have most of my info from a keynote with a professor from the southern university of Denmark

Sewers is a rather weak source of biogas, where as waste bio mass from farmland is a big one.

It’s an on-going technology but this gas crisis is definitely a good motivator to build more biogas infrastructure.

Is it enough to completely replace normal gas? I don’t really know. We can also lower our gas needs by limiting its use to peaker plants. Or we can synthesize gas with excess renewable energy