As discussed in numerous previous posts the world will need immense amounts of energy storage to transition to 100% renewables, or anywhere close to it, and the only technology that offers any chance of obtaining it is sea water pumped hydro (SWPH) storage. Here I consider the practical aspects of SWPH and conclude that there are only three places in the world where a combination of favorable shoreline topography and minimal impacts would allow any significant amount of SWPH to be developed – Chile (discussed here), California (discussed here) and, of all places, Croatia. For the rest of the world nuclear remains the only proven decarbonization technology. (Inset, Valhalla’s proposed SWPH project in Chile.)
In the last few weeks I have wandered through Google Earth looking for prime SWPH potential and have found that most of the world has none (I have not looked closely at Africa). The coastal topography in most places is too low and flat, and where it isn’t the valleys lack good dam sites, and/or are full of people, and/or the sites are too far from the sea. The sites that do exist are also often in scenic areas where significant public opposition may be expected whether there are any people there or not.
This point was forcibly brought home to me by Euan Mearn’s comments on Scottish Scientist’s Loch Ness Monster of Energy Storage guest post, which proposed a 6.8 TWh SWPH upper reservoir at Strath Dearn in the Scottish Highlands. Considered purely in terms of potential Strath Dearn is probably the best SWPH prospect in the UK, but if Euan’s reaction to the proposal is shared by others the chances it will ever get built are effectively zero:
…click on the above link to read the rest of the article…
To support a 100% renewable electricity sector Australia will need approximately 10 terawatt-hours of long-term energy storage. The multi-billion-dollar Snowy 2.0 pumped hydro project will supply only 0.35 terawatt-hours, a small fraction of this, and conventional pumped hydro potential elsewhere in Australia, including Tasmania, will not fill the gap. This post addresses the question of whether Australia might not do better to pursue sea water pumped hydro instead of Snowy 2.0-type projects. Sea water pumped hydro potential in Australia is limited by the lack of suitable coastal topography, but there are sites capable of storing very large amounts of sea water at distances of more than 20km from the coast. The question is whether these sites can be developed and operated at acceptable cost.
If pumped hydro plants that use the sea as the lower reservoir can be put into large-scale operation Chile would be able to install at least 10 TWh of pumped hydro storage along its northern coast. With it Chile could convert enough intermittent solar into dispatchable form to replace all of its current fossil fuel generation, and at a levelized cost of electricity (provisionally estimated at around $80/MWh) that would be competitive with most other dispatchable generation sources. Northern Chile’s impressive pumped hydro potential is a result of the existence of natural depressions at elevations of 500m or more adjacent to the coast that can hold very large volumes of sea water and which form ready-made upper reservoirs.
When and if it gets built the Valhalla project will consist of a 600 MW solar farm and a 300 MW pumped hydro plant which, it is claimed, will in combination deliver continuous baseload power to Northern Chile. If the project works as planned it will indeed deliver continuous baseload power, but only enough to fill about 5% of Northern Chile’s baseload demand. However, it would be the first to demonstrate that baseload power can be generated from a utility-scale PV plant. Development is presently on hold while Valhalla seeks $1.2 billion in financing. (Inset: Valhalla’s solar farm.)
