My partner recently quantified energy use on two of his computers and learned that his 10-year-old Thinkpad consumes 35W when it isn't doing anything in particular, while the much newer Thinkpad he uses for work consumes more like 8W.

As a huge fan of old Thinkpads with strong environmental values and who also tries to avoid discarding old things that are still functional or buying new things I don't need (largely for environmental reasons), I'm at a bit of a loss for what to do with this information : (


@dynamic if the carbon footprint of making a new laptop is on the order of 300 kg CO2e, the 27 W difference (which would require roughly 33 W of generated energy at the power plant) represent around 30 kg CO2e per year in Germany if you use it 6h every day.
So it would take 10 years to make it worth changing.
In France it would take almost a century...
So if you're in Germany and use it more than 6h a day, it's done its time, change it, otherwise keep it


Also, for reference, I am in the U.S. We're signed up for an electricity program through our city that is described as 100% Local Green, but it's not entirely clear what that means.

The sources of electricity are stated to be, "1) Zero emission sources, such as solar, wind, low impact hydropower2; and 2) Sources that destroy methane, such as anaerobic digestion," with the followup statement: "Other forms of biomass are explicitly not purchased by Green Energy Consumers Alliance, due to their positive emissions of CO2 during their life cycles."

I'm not entirely comfortable with their apparent assumption that intentionally setting up anaerobic digestion as a fuel source is a reasonable basis for saying that the energy is "methane destroying."


Also, if I recall correctly, I think that what the 100% means is not that that is now our electricity is actually generated but that 100% of what we pay goes toward development of these kinds of renewable sources, which... I have a hard time evaluating.

@dynamic @tfardet They list the specific power mix at . I'm pretty sure all the electricity has to come from renewable resources that exist today, not future projects.

It seems like to be considered "methane destroying" it should be methane that would have otherwise been released. If they can collect it and turn it into electricity the law probably already required it to be flared.

Both sides of my family are from Springfield MA by the way.

@freakazoid @dynamic what they say seems reasonable: biowate would rot and generate methane if left alone or landfilled and burning it directly is inefficient because of its high water content so anaerobic digestion indeed prevents methane release in the athmosphere and is energetically efficient.
Also nice to see they avoid burning biomass!
However, though I think it's great to use such provider, I think you should use MA grid's mix since that's how you get your electricity (~ 370 gCO2e/kWh)

@tfardet @freakazoid

I don't know a lot about industrial scale biogas production, but I do know that at the household scale you can use either aerobic or anaerobic composting to process organic materials.

For anaerobic composting, you saturate the stuff with water and it starts to bubble. Ideally you then harvest the biogas (I've only done this accidentally, but I believe the principle is the same for a household scale biogas digester).

For aerobic composting, you mix in lots of fibrous material (wood chips, hay, paper, etc.) to give the stuff structure and sometimes you mechanically churn it, although mechanical churning is not required, especially if you have invertebrates like worms or black soldier flies digging around in there.

I don't see any reason why aerobic composting couldn't also be used at an industrial scale.

@dynamic @freakazoid sure, aerobic composting can be done at industrial scales but it does not lead to energy production and can produce methane and other GHGs.
Furthermore, given current agricultural legislations and standard use, we would unfortunately overproduce compost compared to the agricultural demand if we converted all biomass into compost

@tfardet @freakazoid

The point about overproduction of compost relative to agricultural demand is an interesting one, and I'm not sure how easy or hard it is to get around that by first using the compost to grow non-edible biomass (e.g. incorporating hydroponics into sewage processing) and then composting that biomass for agricultural purposes. I believe this kind of system is better aligned with policy, but it occurs to me that the second biomass production step might also add a lot of bulk that then needs to be dealt with.

@dynamic @tfardet Any biomass can be gasified and/or burned. It’s just a question of the quality and therefore economic efficiency of the process. It’s usually not worth transporting biogas because of its low heating value, so it often just gets burned or otherwise utilized on site. You can then capture the CO2 if you want and use it for something else, or sequester it.

@tfardet @dynamic Using pure oxygen for gasification improves the heating value of the output gas and reduces NOx formation, so maybe it would be advantageous to collocate an air liquification plant, especially if the system puts out enough energy to power it. You could use the Fischer-Tropsch process to produce liquid hydrocarbons, or generate hydrogen using the water gas shift reaction and use it to generate ammonia or whatever. Use the CO2 to make concrete.

@freakazoid @tfardet

I thought making concrete was a CO2 source, not sink?


@dynamic @tfardet There are carbon-negative processes, but it remains to be seen if they can be made economic. You use magnesium silicates instead of lime, from olivine, talc, or serpentine. Those will naturally absorb carbon as they weather, so using them to make carbon-neutral concrete acts like an acceleration of the weathering process with a useful by-product. It's mainly a question of whether it's worthwhile compared to other means of accelerating the weathering process.

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@dynamic @tfardet Incidentally, there are enough of those minerals to absorb all carbon on the planet and kill off all plant life and everything depending on it. Which will happen long before we have to worry about the sun stripping away all our water. So if we're still around we're going to have to start adding CO₂ back to the atmosphere. Which will be a lot easier if we've left a bunch of fossil fuels in the ground!

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