What goes up must come down, and a vague memory of school physics reminds me that an object that has yet to come down has potential energy in it. Drop it, and it becomes kinetic energy. That’s the essence of pump storage in hydro projects. On a steep drop between two reservoirs, use excess power at night to pump water uphill, then release it downhill when you need it. When the nation’s kettles are switched on at half time in a big football match, the sluices are opened, water hits the turbines, and power is delivered within very few seconds. It’s much faster and greener than firing up a gas boiler. Norway’s geography has blessed it with a lot of pump storage. The UK’s much less so. There are a few big projects, such as Cruachan, and a couple of sites, including one at the planning stage north of Dumfries, which could be developed. But with only a few possible sites, and daunting cost when you develop one, a much cheaper application of the same very simple physics is being developed by an Edinburgh company. Unlike so many incomprehensible techie start-ups, it has chosen a name that describes precisely what it does. Gravitricity – generating electricity from gravity – is getting noticed by investors, as an effective alternative to large batteries, so that renewable energy supply can be stored until there is demand. No need to go to the Congolese jungle to get hold of the raw materials for batteries. All you need is a lot of concrete, some very strong cables, and winding gear. I simplify a bit. The power also has to be harnessed by turbines and then connected to the grid. And you have to build high towers, or find deep holes in the ground. Gravitricity wants to start with such a tower in Edinburgh, to prove the concept. But it then wants to use mines which are closing, or recently closed, to make use of their deep shafts.
BBC 22nd Oct 2019 read more »
It sounds like magic but it is real – a plan to store cheap night-time wind energy in the form of liquid air. Here is how: you use the off-peak electricity to compress and cool air in a tank, so it becomes a freezing liquid. When demand peaks, you warm the liquid back into a gas, and as that expands it drives a turbine to create more electricity. The technology, created by a backyard inventor, is about to hit the big time. It has been tried at small scale but now the firm behind it, Highview, has announced that a grid-scale 50MW plant will be built in the north of England on the site of a former conventional power plant. The technology has been supported by the UK government. One attractive feature is that it uses existing simple technology developed for storing and compressing liquefied natural gas (LNG), so unlike battery storage it does not require mining for rare minerals. The key innovation is to store the excess heat given out when the air is compressed and use it to re-heat the liquified air when it is needed. The idea was promoted by self-taught engineer Peter Dearman from his garage in Bishop’s Stortford, Hertfordshire. He had been developing a car run on similar principles with liquid hydrogen and saw the potential for applying the technology to electricity storage. He is now a passive shareholder in Highview, which is hoping to play in the big league of storage.
BBC 22nd Oct 2019 read more »
Solar Power Portal 22nd Oct 2019 read more »
Rio Tinto has said it could become America’s largest producer of lithium for batteries after making a discovery at a mine in California that it has described as a “eureka moment”. The Anglo-Australian group said that it had found that piles of waste rock discarded over almost a century at its Boron site contained high-grade lithium, which could be used in batteries for electric vehicles.
Times 23rd Oct 2019 read more »