Biogas — fuel from food waste

I don’t know how things are in your corner of the world, but here in Sweden there’s a lot happening on the biogas front. Making fuel out of food and animal waste would seem to be — on the surface — a cool way of making something good out of something bad.

Which is is. But there’s a few things I wonder about all the same.

The reason for taking it up here is I picked up a New York Times article recently on biogas, and they’re holding up Sweden as an example of how the whole biogas thing can be done and done well. I’m not sure what this means: are we actually out there doing new stuff in this arena, or was it just a fluke that they picked a Swedish town as an example? It would be interesting with some viewpoints from the real world! What’s happening where you are?

First, I can say that the article pretty much represents reality here. Biogas is nothing new, a lot of cities are collecting food waste and manure and pumping it into biogas factories. The pump stations are gradually emerging along with the cars and buses. District heating is common — and makes a lot of sense in a country with many energy-consuming industries (pulp and paper in particular) that can supply the local community with their surplus heat. (But don’t worry — we pay for it! Even with our taxes there’s no such thing as a free lunch!!)

District heating is for the townies, country bumpkins such as ourselves have the standard options.All-time favourite is wood, a tried and tested biological resource in a country such as this. Despite all the pulp and paper and wood-heated homes, we manage to end up each year with some five per cent more trees growing than the year before. A net increase in a country that’s basically covered in spruce from top to toe.

Other options in the home if you don’t have district heating are direct electricity (your standard radiators), but this is something people are trying to replace or make more efficient for cost reasons. Oil boilers are a thing of the past (cost again, let alone the environment). Pellets (wood-based) are big, a convenient form of bio-fuel for boilers and central-heating fireplaces. Rooftop solar heating isn’t really making a mark, although some brave souls are trying. Our winters are so damn cold and we have so little light that it just doesn’t seem that appropriate to try and heat your shower from an arctic sunrise…

On a national supply basis we have a bit of everything much the same as everyone else. Some green. Some not. Some downright shameful (Vattenfall, our more or less monopoly electricity supplier, is deeply into brown coal in Germany…)

But back to biogas. Personally I think it’s great with innovation, it’s great to see a new form of green energy, it’s great to see local biogas production units popping up all over the country, and it’s great to see waste that would otherwise go to waste or up into the atmosphere being put to good use.

My concerns are largely around the issue of biomass. Have we really thought this thing through? By pumping food waste, animal waste, whatever into biogas plants and pumping out gas, aren’t we just making fuel out of soil? Food waste IS soil after all, it comes from the soil, it belongs to the soil, it should go back to the soil. We have it on loan and we should pay it back. Are we really entitled to divert it into another ecoloop, an ecoloop such as fuel in which it will definitely not find it’s way back to being biomass?

Biomass in the world is decreasing as we speak. Every year we have less good land for growing. We have less good soil. We have less possibility to grow food. At the same time as we have a growing population and a changing climate. Not the best of combinations, obviously.

It seems to me that in an equation like that everything that comes from the soil should go back to the soil. Anything else is like living off capital. Taking and taking and forgetting to put back.

Admittedly, there’s two things come out of a biogas factory. One is the gas, well and good, but it’s not soil. The other, a by-product of the gas production, is a soil-like product. THAT at least is sent to farms as some sort of input to the process there. I’ve heard varying reports on the quality of this material though — some say it’s ok, but others say the nature of the gas production destroys much of the value of the soil-like product, it becomes a sort of landfill. Something that would be good to find out more about.

But however you look at it there are pluses and minuses. Big plus: we get a bio-fuel out of something that may well have gone to landfill in many parts of the world otherwise. Big minus: we give away soil from the food production ecocycle. With fat chance of every getting it back.

That’s my two-cents worth anyhow! What’s yours??

Read the New York Times articles here>>

Oh, and by the way — can’t have a whole post with no comment on Bokashi :-). In case you were wondering what the effect would be of pre-processing food waste with Bokashi or EM before it goes into a biogas process, the answer is GOOD. I don’t think it’s done on a commercial scale anywhere so far but pilot tests show the efficiency of the biogas process to be improved by up to 10 per cent when treated with Bokashi or EM. So a synergy effect would be possible, should anyone care to take it on! The convenience for householders would certainly be improved, when you think of collection times, smell, flies and the rest of it.