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Originally Posted by DaveM  To me that's where the economic case for their use in this application hits the rocks.
As for power losses, no system is 100% efficient and nobody familiar with such systems would suggest that they are. The actual losses would have to form part of any cost-benefit analysis on a proposed system. |
Dave M I agree but my arguements are more fundamental.
I am simply cosidering the energy balance of the process. I have shown that to use these storage devices we will loose nearly half of the energy that was originally generated if not more. Regardles of the final cost, this sort of wasteage is unsustainable which is why these devices are used rarely and why in comparison quick startup gas plants are used far more often.
Until any storage device can get to efficiencies of 85% where they are in the region of direct transmission (91% efficient for US) they are not viable. Because as you point out for Turlough hill (and this goes for other storage devices) the cost are truely enormous.
I approach any engineering problem in this way because my goal is energy efficiency. Low cost while acceptable in many cases does not gaurntee efficiency e.g. internal combustion. So I calculate the energy then the cost. Generally speaking for our industrial partners less energy used/more efficient is always a saving.
Using my energy calc and your cost data we can easily put a thumb in the air and say not feasible. If on the other hand you said a cost of 100 million for a system 5 times bigger than turlough hill, I could see that being implemented but I would not be happy. Because to produce say 1000MW we would need 600-800 turbines instead of the proposed 300-400 for the London array.
Units of energy and power-why use watts or mulitples thereof
First remember 1 MegaWatt (MW) = 1000 KiloWatt (KW) = 1000000 watts (W).
A watt is equal to one joules of energy per second. It rates the power for a given decice. For example you have 60 watt bulbs, 1000 W (or 1 kW) microwave or 1600 Watt iorn etc.
To go from Watt to Watt hours you simply multiply the amount of watts (e.g. 1W) by the number of hours. Soo a 100 Watt bulb running for 1 hour uses 100 Watt hours.
In an industrial context we use Watts (well Mega, Terra or Peta Watts) as industrial operations rarely shut down and the price of electricity rarely changes. The energy uses is rarely time dependent or at least defined in that way.
However for a household the load is variable, you may only use a washing machine once a week for four hours etc. The enrgy uses is time dependent and that means you get peak loads and trough loads because of the variability. To cost this, it is much easier to fix your Watthours to a set price rather than your Watts.
In any cases these units are interchangable and what ever your analysis you can use either. However power in Watts and not powert*time *watthours) is the standard. Take a look in your kitchen.
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Originally Posted by Quixote Pumped storage was originally developed to be as you describe a 'load flattening device' but to many people represents the best and only technically viable storage solution to make renewable systems work and to allow the increase in their contribution up to the levels that are meaningful. To me it makes complete sense that a series of pumped storage installations are planned as part of the necessary infrastructure to create a workable system. Yes the process involves a certain waste and loss of energy but the gains outweigh this. At this point in time wind power is being generated which is of little real use as the ESB are still burning the same amount of coal, oil and gas in their central plant. |
The key issue is whether or not this idea of building several Turlough Hills is sustainable. Because of the astronomical energy loses as I have shown that abound from this process, environmentally and economically this idea of several more is not. We would have to double our energy generation to use them. Indeed consider the US. PSH is used for only 2.5% of their grid when operating (Remember we need to fill the resevoir). In that sense I would hardly classify PSH as necessary infastructure.
Right now Ireland needs to begin its alternative energy infastructure. Just building the alternative sources would be a start and that is what Ireland must concentrate one now.
More efficient means for PSH are being investigated as well as improved batteries or