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Comment by illys | Hacker News Reader

It is great we focus on renewable production and I feel it is what we should do at the stage we are.

However there is often no word on the fossil consumption for producing, transporting and installing the huge wind machines.

I guess that "grey" energy should be deducted from the yearly renewable production per windmill with a formula like [mill construction fossil energy]/[average life of the windmill in years].

Showing such digits: 1) would discard projects that have a global negative renewable impact (when considering construction). 2) is a critical incentive to decrease the fossil footprint in renewable installation constructions (wind / sun / hydro...).

Indeed there is a possibility to fuel the industries and trucks with see-water and green-electricity produced hydrogen... But it costs more than petrol and no one can be competitive in such effort if it is not valued to the public by fossil-use transparency and advertisement.

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>However there is often no word on the fossil consumption for producing, transporting and installing the huge wind machines.

There is plenty of research into this. Some terms you can use are "life cycle assessment" and "energy returned on energy invested."

There's a Fully Charged episode on Youtube that looked into this. Hammer's Hill Wind Farm on Orkney paid off their installation and construction CO2 debt in the first 45 days of operation. Despite there being 500 tons of concrete and steel in each base.

https://youtu.be/FXe1hBvlylw?t=87

The problem of the "pay back" is that the CO2 they emit is still in the air: the mill does not absorb CO2.

In addition there are different ways to compute a "pay back":

- you may compare the e-kWh production and the fossil-kWh spent to build... Certainly pointless but useful to display short "pay back" durations.

- you may compare your electricity production with the production of the nearby fossil-plant that you pretend to avoid... More realistic, but your project will have different "pay back" depending on the neighborhood you consider (immediate neighbor, regional mix, national mix...).

I can understand such computations in the transition stage where we are, but in the end, each project should be considered for its own [electricity production]/[fossil emissions] ratio across its construction and lifespan.

As we can't go from polluting forms of generation to more neutral sources without building and replacing... Yet it's still worth doing if that will produce lower emissions going forward compared to simply carrying on with the local coal or gas plant.

Doesn't imply this is merely greenwashing, just a small step on route to zero emissions. Where I want to see more significant and far-reaching progress.

To the general point I agree. I'd far prefer to see full impact required for each project, and overall, as well as labelling showing impact of the things we buy - food, consumer goods, vehicles etc, including all those hidden externalities.

> However there is often no word on the fossil consumption for producing, transporting and installing the huge wind machines.

I assume those "grey" costs would also apply for any other energy source. You always need some kind of plant where you eventually produce and distribute the electricity.

Yes I agree, and it should be counted everywhere.

Its actually very complicated matter to count [1]. But if you look into winds "carbon footprint" you should find it is widely regarded as having one of the lowest overall emissions, about 1-2% of natural gas generations footprint.

[1] https://www.climatexchange.org.uk/media/1461/main_report_-_l...

What you are talking about is called "Life cycle inventory analysis" of and is of course counted in the carbon footprint of a given technology, yes.

Manufacturing energy costs are especially important for solar, which requires important amounts of energy for silicon purification and "monocrystallinization" (there must be a more adequate word). Wind power manufacturing costs are on par with other technologies.

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