With current technology, how much CO2 is emitted when making renewable power plants?

Question

In order to make a solar panel or a wind turbine, a few basic inputs are required:

• labor
• energy
• water
• raw materials

Given the current abundance of renewable resources, I assume that the first three components can feasibly be provided with no carbon emissions.

But what about raw materials?

Are there components of solar panels or wind turbines that directly result in carbon emissions? If so, how much carbon per watt of capacity is emitted in production of these components?

I know that the process currently used to produce concrete results in carbon emissions (see Wikipedia), and that alternative processes have not yet proven to be reliable or affordable at large scale. Are there additional components that also result in some inherent carbon emissions?

For this question, please ignore the impact of land use change as any energy source will require some land, and the emissions level will depend on where the plant is built.

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If this question is too broad as written, I'm happy to split up solar and wind into separate questions.

Answer 1

Since raw materials scale according to size, every different panel/turbine will have a different answer. Different generators also have different maintenance costs, and lifespans. It's probably more meaningful to look at the total — lifecycle — cost of generation, not just a generator's initial construction cost.

Carbon Brief have a 2017 article that delves into lifecycle emissions somewhat (it references a Nature Energy paper that is, unfortunately, behind a paywall):

Lifecycle direct and indirect greenhouse emissions associated with generating a unit of electricity from different fuels, in a 2C world in 2050 (coloured bars). The colours break down these emissions by source. For comparison, the light blue ranges show the range of results published in the latest Intergovernmental Panel on Climate Change assessment, AR5. Source: Pehl et al.

Taking the long view...

• Wind emits 4g CO₂ (equivalent) per kWh
• Nuclear also emits 4g
• Solar emits 5g
• Gas emits 78g
• Hydro emits 97g
• Bioenergy emits 98g
• Coal emits 109g

Not exactly what you were after, but hopefully useful anyway.