Where are all these batteries and solar panels made ? How much GHG was emitted to build them, and how much GHG is expected to be saved by choosing this kind of electrical grid instead of alternatives ?
What are the alternatives? 100% nuclear with breeder reactors so that we don't run out of fuel in a couple of decades? How quickly can you build the required number of reactors? What do they cost?
Those cost greenhouse gases to build as well! The question is mostly a distraction, deliberate from some. We of course also need negative emissions; there is no way around humanity causing some greenhouse gas emissions in the foreseeable future.
For example, imagine a solar panel that costs $1000. They probably cost about $1000 to make, roughly. There may be some subsidy that allows them to sell at a loss but it’s safe to say it costs around $1000 to make, at a maximum.
You can also presume that energy is a factor in the cost to make a solar panel. So if 100% of the cost of the solar panel is energy, then some factory spent $1000 on energy to make that panel, max.
So that’s your hard limit on how much CO2 is being produced in the production of that solar panel: $1000 dollars’ worth.
I can't recall the source, IIRC it was EU research that looked at the lifetime carbon footprint of all energy sources. 'green' sources like wind and solar have a considerably lower footprint.
Which would make sense. At least in the UK, onshore and offshore wind are the cheapest sources going. Would suspect the amount of energy put into creating and maintaining them would mean that the LCOE is lower.
In a 100% renewable economy, where are the emissions coming from? Renewable sources don't create carbon atoms out of nothing. Cement production, maybe? Solar doesn't need cement!
If the economy is not yet close to 100% renewable, what matters is not small CO2 emission from making the renewable sources, it's how rapidly the remaining fossil sources can be displaced.
I'm not sure if there's such a thing as a 100% renewable economy, perhaps if you mean energy inputs yes, but there's always(?) going to be processes that involve emissions through 'work' as well as any emissions to create those renewable energy sources.
We can always offset. I mean, burning fossil fuels in itself is not a bad thing, but we know they're a finite resource and we simply have to offset those emissions with carbon sequestration.
Why shouldn't there be a 100% renewable economy? What energy inputs cannot even in principle be substituted for with renewable energy?
The reduction in fossil fuel usage needed to get to a climate-sustainable level is so large that any tolerable residuum could instead be handled by biomass.
The question is valid.
But you need to ask the same question for a coal or gas fired plant which does emit GHG over its entire lifetime on top of what was needed to construct it and what will be needed to deconstruct it.
I have heard that there are by now numerous studies that show batteries are better in cars as well as grid. Unfortunately I have no link handy
That's a good question that people use badly to sidetrack discussions about solar. The answer is that most research accessible online places the EROEI of PV solar at around 10. That places it in a firm "can be used" position, but too low for explosive growth, so any fast conversion into solar will need a large investment from some other energy source.
But notice that most research accessible online is old and solar is improving fast (while the fossil fuels can do nothing but get worse with usage).
There's a comprehensive comparison here that is interesting:
