by Keith_McClary » Mon 24 Nov 2014, 19:41:22
$this->bbcode_second_pass_quote('', 'P')umped storage is the largest-capacity form of grid energy storage available, and, as of March 2012, the Electric Power Research Institute (EPRI) reports that PSH accounts for more than 99% of bulk storage capacity worldwide, representing around 127,000 MW.[1] PSH reported energy efficiency varies in practice between 70% and 80%,[1][2][3][4] with some claiming up to 87%.[5]
https://en.wikipedia.org/wiki/Pumped-st ... lectricity I can't see where Energy Cache gives efficiency numbers.
The mining industry uses conveyor belts, I don't know how the bucket system compares.
$this->bbcode_second_pass_quote('', 'A')t the Los Pelambres opencast Copper Mine in Northern Chile, carbon free electricity is produced in a very original way. Crushed rock containing copper ore is used to generate electricity as it travels down from the high-altitude mine to the processing plant located in the valley below.
The conveyor belt transporting the ore is 1.80 metres wide and 13 kilometres long, going from an altitude of 3,200 metres above sea level down to 1,600 metres. The ten drive motors of the belt consume power only if the belt is carrying less than 800 metric tons of ore per hour. During full operation, the belt carries 8,700 metric tons an hour and functions in generation mode, providing up to 17 MW of power.
In 2007, the belt produced 90 GWh of electrical energy, equivalent to 15% of the mine’s own power needs. One could argue whether this type of electrical energy is truly renewable or not, but it certainly qualifies as zero carbon emission. The system saves about 50,000 metric tons of CO2 per year. It not only reduces the environmental impact of the mine, it also reduces electricity costs, making the site one of world’s most profitable mining operations.
http://www.leonardo-energy.org/copper-o ... lectricity