Well you also need to solve the storage problem. Your solar plant will not replace the coal or natural gas plant at night or on cloudy days.
As you say intermittency and time of day is the issue. Although I think we should just reflect lower costs in time of day tariffs. I suspect there are a lot of use-cases where people would happily shift demand to save money. For instance if you could just put your clothes in a washer dryer, and leave it to handle the cheapest time. Or air conditioning which creates ice earlier in the day then uses the cache later. Provide the tariffs, open the market opportunity, and see what technologies emerge.
The storage 'problem' doesn't really exist. Do we 'store' electricity currently? No, we just generate it all the time and it's 'used' straight away. Well, what we do technically now 'store' will continue to be stored if using wind/solar (e.g. pumped hydro 'Electric Mountain' in the UK).
Shall we also pedantically say we current 'store' electricity in the form or chemical energy in gas/fossil fuels or whatever? We can use that definition I suppose.
Even with that definition no leap to any new 'storage' method actually needed if we look at the functional output required to keep the system operating the same way it does now. You just need need to have enough renewable over-capacity to generate enough electricity to meet the 24h cycle. Which is functionally what we do now.
The "it's always windy/sunny/tidal somewhere" solution is the same as what we do currently, we just put our hands over our eyes and ignore the 'energy security' implications of not producing enough oil/gas to meet our own needs so it feels like somehow what we have now is more certain.
That's not to say it wouldn't be more efficient to store electricity and release it as needed. But just like now what would solve the problem is over capacity with enough resilience to feed the 24 hour cycle.
Can that be done with 'just' wind and solar? I don't know,I guess not. Nuclear would seem a good addition to the mix, and tidal or wave power.
But it seems like we should at least approach the problem openly without hamstringing ourselves worrying about 'storing' electricity being something we absolutely must 'solve' before renewables can be relied upon.
Right, and we vary how much we produce to match demand. We can't make it sunnier just because everyone has gone to put the kettle on at the same time.
If there wasn't enough generating capacity in the fossil fuel system it would be equivalent to 'can't make it sunnier'. The flip side to 'can't make it sunnier' is you can add more solar generating capacity (over-capacity) and add mixed generation through wind/solar/tidal. Both options end up at the same place - over-capacity in order to meet peak/daily/yearly loads.
Classic fossil fuel generating stations quite literally sit idle waiting to go, that's the over-capacity. The same thing can be done for renewables (the whole mix, not just solar).
And to answer the inevitable 'but we've always got access to fossil fuels, like at night when the sun doesn't shine'...
Right now we 'store' the electrical energy in fossil fuels (really we release it) and say this system if inherently more stable because we assume access to those fuels is immutable. And we say that the energy 'stored' in the wind or tide or sun is not.
In reality, fossil fuel energy security is a delicate balancing act of just in time logistics and political power plays, for most nations without vast resources or nuclear generating capacity for instance.
Functionally, perceived limitless access to fossil fuels gives the false impression of superiority and conversely give the the perceived absolute need for renewable storage because of the very obvious daily cycle of light/wind/tide.
I simply say that adopting a system of over-capacity like we currently have for fossil fuels and recognising that neither renewable/fossil fuel resource access is certain is a sensible middle ground upon which to build a sensible generating program. Both systems can rely on having more capacity to handle peak loads, both systems have the ability to plan for their faults and both can work without massive grid scale storage.
Adding storage to renewable generation would actually be a huge step up over the current system and would be fantastic. I would love to see such a system work, and I believe it will do anyway through distributed smart grid/EV usage and large grid scale battery storage.
It's just the uncertainties of the current system are hidden from the average user and I'm just saying we're setting a higher bar for renewable use and storage because the access limitation are that bit more obvious on the daily cycle.
So you are effectively asking for a 3-5x lower solar cost before it could replace existing sources. Never mind that there are seasons and periods of the day when no amount of excess capacity will cover the demand, there is simply no significant solar energy on continent-wide scales.
I've repeatedly said to use a mix of renewables, just like a mix of fossil fuels is used, so deficiencies in one is balanced by another.
The exact same thing is done in traditional generation. You don't use a nuclear plant t for a TV pickup for instance, you wouldn't use solar for the whole grid.
Balancing the way you generate reduces the amount of over-capacity required (and subsequently the cost), exactly as is done now in traditional generation.
I’m optimistic, but we’re not there yet.
Also hydrogen.
120 m * 35,000 kg * 9.8 m/s/s = 41.2 MJ = 11.4 kWh.
LiIon: 250–693 W·h/L, 100–265 W·h/kg, 250~300 USD/kWh in 2018
-> 11.4 kWh = 45.7-16.5 litres, 114-43 kg, $2850-$3420.
Concrete is much harder for me to find number for, seems to be $92/cubic yard, 2.4 tons/cubic meter.
35 tons -> 14.5 cubic meters -> ~19 cubic yards -> $1748 plus whatever the cost of a crane that can lift 35 tons is.
My knowledge of cranes is whatever came up first on Google:
“””A Comadil CTT 361-20 is a good size crane able to do concrete panels, max jib length is 75 meters and they have a max lift capacity of 20 tonnes. These cranes can go up pretty high without needing to be tied into the building. This crane will cost around $1 million”””
Article later talks about renting smaller 4-5 ton capacity cranes for $1500-$2000 per week.
The problem is neither LiIon nor concrete with cranes nor hydrogen are cheap enough. Not yet.