lowtechmagazine

You expect me to deal with all the -5% waste sources in one article?

Please explain me: what is the minimum share of total energy use that any activity should have before someone is allowed to dedicate any attention to it?

Author here. Good point, and I wanted to add that this is the first article in a series about communal living.

"Learning and practicing how to correctly pull the trigger is probably the single biggest improvement to accuracy a new shooter can make."

Thanks, I will change that sentence.

Happy to see that someone actually read the whole article before making a comment.

Thanks for spotting the mistake. km2 should be m2.

Source: https://repository.tudelft.nl/islandora/object/uuid:1ed44c19... page 17

None of the laptops was brought to landfill, I still have them at home, which is why I could photograph them all.

The malfunctioning charger was not the only problem. The Apple laptop had also gotten extremely slow. Because I was not aware of Linux (this is 15 years ago), I made the mistake of thinking that I needed a new laptop.

This is the whole problem: many people are not aware of Linux and its advantages, and thus keep falling in the trap that the hardware and software industries have set up for them.

Author here. That sentence will be deleted when the website regenerates, cause it doesn't seem to have the effect that I was aiming for. Thanks for pointing it out.

That said, I was impressed by the man's repair qualities. I asked him how he was going to repair my 2006 laptop without access to spare parts. He said he would just repair the fan by replacing the copper wire. Don't see that happening in an official repair shop. And he did it overnight.

Now that I have some more time, I actually do want to address your comment in more detail.

1. "Kris De Decker just really doesn't like plastic!"

Correct. We need to get rid of plastic. Keep reading me if you want to know how.

2. "TEGs tend to get burned up"

Not if you build a well designed stove, which is what all the research in the article is about.

3. "They are not going to run your vacuum cleaner or your e-scooter, contrary to the misleading illustrations in this article."

There are several references in the article to prototypes of thermoelectric heating systems that actually do provide enough power to run a vacuum cleaner or an e-scooter.

4. "The truth is that solar panels are not being recycled because almost all of them still work"

Just read a bit about the recycling of solar panels, OK? You can find the references in the article.

5. "TEGs are not "less costly" than solar panels."

In your calculation, you completely ignore the energy storage and the installation. And that's where the cost advantage of the TEG is. Also, no need to oversize generation capacity. RTFA.

6. "The apartment I'm in here is primarily heated by an air conditioner with the capability of functioning backwards, in which mode it produces about 3 kilowatts of heating in exchange for a single kilowatt of electricity."

So where are you getting that single kilowatt of electricity from? Also, can your air conditioner also cook your food, heat your water, and maybe even provide you with lighting? No. You need a lot more electric appliances (and infrastructures) for that.

7. "So what could have motivated such a mendacious article?"

You would not have the balls to say these things in my face.

That's because you're living in a rich country where energy is cheap and abundant. That 40% of the global population that needs to walk for miles to charge their phone for a hefty price, or light their shelter with torches, are very happy with that trickle of electricity. Maybe we -- cause I am also in a rich country -- could learn from that.

"If energy systems were installed that could heat and power these places without biofuel at all you'd be vastly better off. I did not see that point in there."

What energy system you had in mind?

Solar panels could provide electricity, but they don't produce heat, which is vastly more important in the household. A solar PV installation that powers an electric cookstove and heater is unaffordable, even for many people in rich countries.

A "central non-combustion power plant that doesn't emit air pollution or carbon"? What fuel is it running on?

Why would I repeat what is already written in the article?

They are not. For all the reasons mentioned in the article.

Depends on the stove. Tile stoves or masonry heaters can be +90% efficient. The same goes for inefficient stoves without a chimney, which is the majority of stoves in poor countries.

You seem not to realize that 40% of the global population IS ALREADY burning wood as their main source of household energy use. What is your alternative for them?

Maybe read the article before you comment?

Here's the last two paragraphs:

A thermoelectric heating system that runs on fossil fuels also compares favourably to a large cogeneration power plant, which captures the waste heat of its electricity production and distributes it to individual households for space and water heating. In a thermoelectric heating system, heat and power are produced and consumed on-site. Unlike a central cogeneration power plant, there's no need for an infrastructure to distribute heat and electricity. This saves resources and avoids energy losses during transportation, which amount to between 10 and 20% for heat distribution and between 3 and 10% (or much more in some regions) for power distribution.

A cogeneration power plant is more energy efficient (25-40%) in turning heat into electricity, meaning that in comparison a thermoelectric heating system supplies a larger share of heat and a smaller share of electricity. This is far from problematic, though, because even in Europe 80% of average household energy use goes to space and water heating.

You have completely misunderstood the article. Try reading it again with an open mind.

Agreed that it's a one-time step decrease, and that the progress continues. But, why 2020? The panels that have powered the server were bought between 2015 and 2019, and who knows how long they had been in storage before I bought them.

You take the solar panel that just comes out of the factory as a reference, but I could just as well argue that the reference should be the age of the average solar panel installed in the world.

Also, let's wait and see how the move to China affects the quality and life expectancy of solar panels. And what it means for other forms of pollution. I focused on energy use but there are other environmental concerns with the production of solar panels.

I will be happy to update the calculations in the future if more and better data are available.

Calculating embodied energy based on costs is an option, but I have always learned that it's the last resort, as it has many problems, too.

For example, How do you account for the fact that all production facilities for solar panels have moved to China? If you look at the price evolution of solar panels, there's a gradual decrease due to technological progress (less energy use indeed). Then, from 2009 onwards, the decline in costs accelerates sharply, the consequence of moving almost the entire PV manufacturing industry from western countries to Asian countries, where labor and energy are cheaper and where environmental restrictions are more loose.

https://solar.lowtechmagazine.com/2015/04/how-sustainable-is...

No, it's not just Spain. I only looked at European power grids, but their carbon intensity is all calculated in the same way.

A cost analysis remains to be done. But it's not as bad as it seems: we save $600 per year on hosting services.

The obsolescence of life cycle analyses is a topic in itself, and the lack of accessible data is a problem for anyone who tries to investigate high-tech products.

For the solar powered website article, it's the order of magnitude that matters. You say I overestimate the energy use of solar panel production, but in our configuration it corresponds to just 1 liter of oil per year.

The carbon intensity of the national grid is calculated as follows: carbon emissions of burning coal and gas in power plants (say 600 g/kWh) + carbon emissions of wind turbines, solar panels and the like (0 g/kWh). Embodied energy is not taken into account.

That's because you're not on the solar powered website. Hackernews is linking to the old site. https://solar.lowtechmagazine.com/2020/01/how-sustainable-is...

It's a bit more complex than that. The life cycle analysis of high-tech products takes many years. That's why most studies seem to be outdated even right after they are just published. It's not just solar panels. Try looking for a life cycle analysis of a recent laptop.

Author here. Good you mention this. I could have chosen a more elegant citation, but data on the embodied energy of PV modules is generally outdated and confusing. The number I chose is not especially high for panels produced since the 2000s. For an extensive literature summary from 2011 see 2.3 http://www.seas.columbia.edu/clca/Task12_LCI_LCA_10_21_Final...

Also keep in mind that all the panels we tested are much smaller than the ones oin those studies. This means that things like the frame, wires, connections become more important for embodied energy.

My article shows that heating without electricity is cheaper and more efficient than heating with electricity. It also has references to back up these claims. What you write is simply untrue.

"The article doesn't show a single non-demo installation".

It does. The Calorius windmill was commercially produced for about a decade, 40 of them were sold. Seventeen of these windmills were still operating in 2012.

It's all in the article. Also your points about the savonius are addressed.