Monday Message Board
Open for discussion
Another Monday Message Board. Post comments on any topic. As a reward to paying subscribers, I’m limiting comments to them. But if you want to comment for free, you can do so at my blog
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The proposed appointment of Tulsi Gabbard as Director of National Intelligence for Trump will send the neo-cons absolutely ballistic. This position is a Cabinet level position and is in charge of 7 security agencies including the NSA. Gabbard is an interesting character. She is very much against the military industrial complex view of the world, she's an isolationist, she's extremely anti Muslim, pro Israel, and a supporter of an Australian style health system for the US. She does not support aid for Ukraine as far as I can see, and seems to take a position on Russia and Ukraine similar to Jeffrey Sachs. Check out her Wikipedia page. If she is appointed she will be a cat among the pigeons.
Marine pumped storage
This was news to me, but one of the German Fraunhofer institutes (a great but unemulated model) has been working on it for some time. The idea is beautifully simple. Press release https://www.iee.fraunhofer.de/en/presse-infothek/press-media/2024/fraunhofer-iee-and-partners-test-spherical-energy-storage-on-the.html :
“After a successful field test with a smaller model in Lake Constance, the researchers are now preparing a test run off the Californian coast [at Long Beach] with partners. In the "StEnSea" project, they will anchor a hollow, 400-ton concrete sphere with a diameter of nine meters at a depth of 500 to 600 meters. By emptying the sphere, the storage is charged. When water flows in, electricity is generated – it is discharged. [...] It will have an opening at the top, into which an underwater motor pump, also called a pump turbine, will be integrated in a pipe. [...]. An underwater cable connects to the power grid on land or to a floating transformer station of an offshore wind farm. To store energy, the motor pump pumps the water out of the sphere against the pressure of the surrounding water column. The cycle can then begin again. […] The power of this prototype is 0.5 megawatts, the capacity 0.4 megawatt-hours. (*fn)”, The pump and control unit can be removed for maintenance.
The promoters say future designs will be competitive with current storage technologies, but they would say that. More important, the scheme has several knowns and probables going for it.
• The technology is new and specific, but no more demanding than the deepwater machinery already in daily use at similar depths in offshore oilfields, wind farms and submarines. It is likely the things can be built and operated reliably.
• Fraunhofer propose an operational depth of 600m, as at Long Beach. Land-based pumped hydro typically needs a 300m head, and the marine tanks are much smaller. This means that the <100m continental shelves where fixed offshore wind turbines go are too shallow. That’s a major constraint, but leaves a lot of suitable coastlines. Schemes will need to be big, like offshore wind farms, to justify the long underwater cables. On the other hand, sea-coasts are where people live, not in mountains near to pumped hydro dams, so the transmission cost comparison is not automatic.
• The scheme is inherently highly modular and scalable, the secret of lowering costs over time. You pick one standard size of concrete sphere, and build a shipyard to make dozens or hundreds of them. A 30m sphere has 37 times the volume of a 9m one, and only 11 times the surface area, which determines the volume of concrete, so you save by going as big as possible – the constraint could be with the removable pump unit. The spheres can be towed half full to their operating site. You would get 18 MW/15 Mwh from simply scaling up the Long Beach pilot, though 4,400 tonnes of concrete seems a lot for the capacity. Perhaps they could recycle surplus LNG tankers, which have large, robust and spherical pressurised steel storage tanks.
• At the suggested depth, very little sunlight can penetrate the ocean, and seabed marine life is scanty. There is some, and the wreck of the Titanic at 3,800m has been colonised. https://upload.wikimedia.org/wikipedia/commons/thumb/9/9c/Titanic_wreck_bow.jpg/330px-Titanic_wreck_bow.jpg The total area of disturbance will be tiny as a share of the whole. There aren’t likely to be showstopping environmental concerns.
The world already has okay technologies to meet all the challenges of the energy transition except for large-scale carbon removal. Additions to the portfolio are nice, but are only needed if they can show some clear advantage, noy necessarily financial, over the baseline solution. Seabed concrete golf balls are clever and feasible, so they are in with a chance.
Footnote
Energy storage systems have two main technical parameters, energy in watt-hours and power in watts. The former is more fundamental. The energy capacity is fixed by the physics of the system. The power draw is a technical choice and can vary over a range. The Bath County pumped hydro scheme in Virginia, for decades the world’s largest, was originally built with 2.1 GW of generating capacity. The owners later upgraded this to 3.0 GW by replacing the pump turbines, the storage in the upper reservoir being unchanged at 24 Gwh. https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station