The water being pumped up hills is very popular… and the energy problem more complex than most people think. I have a few points that are interesting.
The pumping of water up hills is not a power producer, true, but hydro schemes work on flowing rivers from one height down to another and these are power producers but at the cost of reducing river flows and destorying areas of beauty in some cases.
The ones where the same water is pumped up and then let to run down is for a very different reason, during the day there is a great demand for power, huge and so all the power stations are all full stretch, during the night this demand is so small as we’re all asleep, as mentioned before you can’t just turn this things on and off it takes hours to warm up and prep these turbines and so what they do is use the night time to pump the water, the cost of pumping it knowing they can draw on it later is worth it considering the cost of having to shut the power down as and when its on demand. This also allows the flow to be levelled out, as the water then gives enough to average out the peaks and drops in the power supply. It is not really a true eco friendly method.
second point, when i worked at an electricity distribution company, i remember there was talk about having regional blackouts in areas, even to the point that the building we were working in was to run on diesel genny for a weekend and they were going to shutdown power to some areas, during this i was told the grid runs at 97% of its capacity and during this time two main power stations were down due to health and safety breaches…
of all the power produced in this country around 7-8% of it is from renewable energy (taken from uni lecture notes) and of that 75% of it is from biomass, wind, solar and hydro are great but they are pointless, they will never be able to provide for our needs truely they can assist but they will never manage it, the only way we can ensure future generations true supply is to invest in nuclear and to look into improving this technology as i believe the current nuclear fuel supply is about 70 years (unless they can get a way to use the rest of the uranium)
So wind farms and tidal energy really don’t make a huge difference,
A lot of companies looked at wave generators and the like originally and decided not to invest as they were not economically viable and it is only due to the huge grants in this field that makes such projects possible,
I don’t think we should be flippent but i do feel we are chasing a false hope here, even at best these devices will never provide the needed power.