[kyrra]

Manufacturing isn't free.

https://spectrum.ieee.org/green-tech/solar/solar-energy-isnt...

> Making solar cells requires a lot of energy. Fortunately, because these cells generate electricity, they pay back the original investment of energy; most do so after just two years of operation, and some companies report payback times as short as six months.

While the above article is from 2014, it likely still applies today. I would be interested to know how much manufacturing processes have changed since then.

The other big thing the article points out is the toxic chemicals and toxic process used to produce solar panels.

[floatrock]

Energy requirements of various technologies is commonly measured with a simple ratio called ERoEI -- Energy Returned on Energy Invested.

Basically, any energy source can be thought of as an "energy multiplier" -- it takes some amount of energy to free the resource (manufacture it, mine it, etc.), then it produces some amount of energy output over its lifetime. So by looking at energy-out / energy-in, you get a sense of your bang for your buck.

Looking at the latest figures on wikipedia https://en.wikipedia.org/wiki/Energy_return_on_investment#Ap... :

- Conventional oil wells are 18-43:1 (I've heard saudi oil wells -- the easiest to drill -- are in the range of 60:1)

- Shale is 1.5:1 (say you what you will about the shale revolution, but from an energy output point of view, it's literally scraping the bottom of the barrel)

- Oil sands are 5:1

- Wind is 20-30:1

- Solar is 9-34:1

As with any lifetime/embedded cost analysis, there's lots of variability dependent on your assumptions, manufacturing conditions, and operating conditions. There's nuances in energy types, like wind turbines produce electricity but require tons of diesel trucks and concrete to assemble.

But we can roughly say that in terms of energy requirements, solar is more efficient than shale or oil sands, but it tops out at the lower to mid range of conventional oil.

[gruez]

>- Shale is 1.5:1 (say you what you will about the shale revolution, but from an energy output point of view, it's literally scraping the bottom of the barrel)

>- Oil sands are 5:1

wtf? I thought oil sands were the least efficient but shale is even lower? Is there a source for this?

[ReactiveJelly]

So a model based on pollution taxes would have worked better - We could tax the manufacturing plants, and the coal plants, and have a bake-off to see which is cleaner - Burning coal for power, or burning coal to run factories for PV panels.

But it would have been less popular, because at least in the USA we don't have a good welfare system to balance out the indirect tax on poor people, who have to spend more of their income on electricity, gasoline, other pollutants.