I'm surprised it's this big. This sounds like enough grid scale storage/dispatch to do 100% renewables. Particularly if some of this hydro can be converted to also pumped storage in summer just to shift energy during the day.
I'm in Portugal and was surprised to find out our grid is a net exporter in winter (wind+hydro) and net importer in summer (a lot of fossil and very little solar yet). Getting to 100% renewables should be easy for us. Solar works very well here and is being ramped up fast and the hydro solves the grid scale storage/dispatch problem. Our total hydro is 14 weeks of full load, which is 2x but I was expecting it to be a much bigger difference.
I might cover short-term variability but not seasonal differences. In Germany PV generation varies by 5x between summer and winter and in the Nordics it's obviously even more extreme. Unlike some other locations peak consumption also doesn't coincide with peak production since more energy is needed for heating during winter than for ACs during summer.
I imagine that in a near future where most cars are electric (and thus transportation is a significant part of electricity demand) it should be quite easy to temporarily reduce demand, even in winter: just stop commuting for a few days (at least all office workers). Also big industrial consumers could be incentivized to reduce demand when supply is too low. It might require some design adjustments, but shutting down most industry and working from home for say 0-5 days a year is surely more cost effective than massively overbuilding renewable energy supply, making giant batteries.
Priorities should probably be 1. More grid interconnections (even out supply variability), 2. cheap long term storage like hydro, 3. demand reduction. I think we need all three to transition to a 100% fossil free future.
There isn't much growth potential for hydro since it's more dependent on geography than the others and many sites are already occupied. Short of mega-projects trying to exploit ocean currents.
> Build enough wind and solar to cover the total energy needs evenly during the year
That means you need to overbuild PV and wind independently, which may be an option but a costly one. And you'd still need more storage, 6 days are too short, there are lulls that last longer than that.
If seasonal storage can be built then it would complement both sources and could decrease the required overbuild factor. So it's still good idea to pursue it to reduce cost and reliance on a single source type.
But there's significant potential in wind, particularly offshore.
> That means you need to overbuild PV and wind independently, which may be an option but a costly one.
Quite the opposite. Exactly because wind and solar have opposite seasonality you need to overbuild less in total with the sum of both than you would independently. See the spreadsheet. The 100% renewable scenario only requires 15% overbuild in total and it's all in solar which is now the cheapest electricity source ever. It also maintains net exports to the rest of Europe over winter which is probably when those exports are most valuable.
> And you'd still need more storage, 6 days are too short, there are lulls that last longer than that.
Even when in a "lull" the sources aren't at 0. 6 days of full load fills gaps much larger than 6 days.
> If seasonal storage can be built then it would complement both sources and could decrease the required overbuild factor.
It would have to be very cheap to be competitive with only 15% of overbuild, particularly of solar. I don't think any of the existing or proposed technologies come even close.
What? North eastern India (e.g. Leh) has hydro only in summer as the snowpack melts. In winter it can be -30 C with limited solar resource.
One project I'd like to see get implemented is connecting Iceland to Britain to give 24/7 renewable baseload energy via undersea cables to Britain and potentially to mainland Europe. This would reduce the need for so many battery capacity being built out.
Sure, it would take some investment, but isn't the technology already here?
Maybe somebody else has examples of well running geothermal power plants but at least the Swiss are quite vary of them.
Sure, it's hard to know how far geothermal in Iceland could scale..
But there is an active volcano, how much worse can it get? :)
Despite all the recent talk the real barriers are lack of political will and investment, it was viewed as an emergency we could pull it off very quickly indeed.
1050 km to reach the tip of Norway (or Ireland).
Each branch wouldn't be that different in distance from the part between Cyprus and Crete from the https://en.wikipedia.org/wiki/EuroAsia_Interconnector or the related https://en.wikipedia.org/wiki/EuroAfrica_Interconnector
Looking forward to this coming online. Very beneficial for Ireland after Brexit.
A second source if needed:
But there's no evidence that energy volumes moving between the EU and UK have declined since Brexit. In fact, trade volumes have increased on last year, due to the new France-Angleterre 2 (IFA2) interconnector coming online in January.
Additionally, there are multiple further new interconnectors under construction or being planned for the 2020s. Despite changes to the details of how the market operates, the UK will be increasingly closely tied to EU energy markets by virtue of being more physically connected to them.
UK interconnectivity with Europe to rise despite Brexit:
Solar thermal also makes more sense where you're directly utilising the heat generated, eg: for industrial processes. If you're just using that heat to spin turbines to make electricity, you're adding a layer of inefficiency.
In contrast, solar thermal runs at extremely high temperatures to begin with, so even in a hot climate, there's a huge temperature difference from which to extract power.
It seems to me that mirrors would be cheaper than photovoltaics, and the power-plant itself is a fixed cost, so most of the cost must come from the motors and electronics needed to angle the mirrors, and the maintenance of that.
I wonder: could you have a system where the mirrors are all fixed in place, and you simply move the target as the sun moves. (Or at least move a smaller set of mirrors/lenses that refocus the light onto a fixed target)
There's also a nice scalability aspect to PV: if you want to expand your plant's output, it's really just a matter of adding more panels as you need them. Where as once you hit the limits of your collector/turbine/etc, you pretty much need to build a whole new plant to expand it further.
One of the world's largest solar farms is in Dubai, obviously an extremely hot region. It contains a mix of PV and thermal technologies, though it sounds like they are leaning towards more PV for future phases:
This site https://www.scottmadden.com/insight/solar-photovoltaic-plant... estimates $60 per kW-year for maintenance. Half cleaning; most of the rest in inverter replacement. How does that compare with turbine I wonder.
Cleaning is certainly a cost in dry areas where dust can coat the panels. But generally not in temperate climates where you can rely on self-cleaning via regular rainfall.