# Conservation of electricity

1. Sep 21, 2008

### craze4physics

i was just thinking of the massive powercuts in india.......... why can't we store the excess electricity produced during winters( due less usage of heavy duty appliances) and use it during summers????????? is there a way to do so???????

2. Sep 21, 2008

### MATLABdude

You would need to convert the electricity to a http://en.wikipedia.org/wiki/Grid_energy_storage" [Broken] and then convert it back when you needed it.

For short intervals (say, giant battery arrays for windfarms for days when there is less / no wind), and on small scales (say, a home http://www.beaconpower.com/index.htm" [Broken] to allow for off-peak electricity buying, or in event of a prolonged power outage, or an Uninterruptible Power Supply for your computer) this has been done.

What has not been done is to do this "buffering" on a massive scale for a long duration (say, all of India, during the four months of summer). Something of this magnitude would need to be massive, or in every home, or both. It all comes down to economics: how expensive is it to store this energy (including conversion and storage efficiencies), as opposed to building more capacity, and is there enough money to do either?

Last edited by a moderator: May 3, 2017
3. Sep 21, 2008

### dlgoff

http://en.wikipedia.org/wiki/Pumped_storage" [Broken] comes to mind.

Last edited by a moderator: May 3, 2017
4. Sep 21, 2008

### Redbelly98

Staff Emeritus
Water evaporation could be a problem if the energy storage time must be for several months.

5. Sep 21, 2008

### dlgoff

Then what do you suggest?

6. Sep 21, 2008

### Redbelly98

Staff Emeritus
I would suggest somebody who knows more than I estimate how much of a problem water evaporation would be. Same goes for how long a battery can hold a charge, or how long any proposed energy storage method can effectively store the energy.

Or, perhaps the evaporation rate could be minimized somehow. For example by covering most of the exposed water surface, if that's feasible.

7. Sep 21, 2008

### chayced

Pumped storage hydro, at least by my thinking, only works when you have a natural tank at high altitude to pump into. Otherwise you need to build a huge lake to put the water in.

Also where is this water going to come from? Freshwater sources are going to be more limiting then the amount of electricity you are able to store and saltwater sources are at sea level. Sure having a source of backup freshwater would be nice, but I don't see this balancing out.

It's probably cheaper and easier to just have more power plants running in the summer. If solar power becomes economically feasible then it's also a much better answer.

8. Sep 21, 2008

### Pumblechook

There is no easy way. Converting energy from one to another is always wasteful.

Dinorwig (Electric Mountain) comes to mind but it is not really a electricity storage facility but a very fast back-up to maintain the mains frequency until extra power stations can be brought on-line if the frequency starts to slip below an acceptable limit.

9. Sep 21, 2008

### stewartcs

Why not just stop producing excess electricty in the winter since demand is down?

CS

10. Sep 22, 2008

### MATLABdude

An old joke goes as follows:

The optimist thinks the glass is half full.
The pessimist thinks the glass is half empty.
The engineer thinks the glass is twice as big as it needs to be.

11. Sep 22, 2008

### Pumblechook

Excess elec??

Are you joking?

12. Sep 22, 2008

### Muralikrishna

Hi! I got an idea but dont know how far it is viable! please revert. solar power during day time is to be charged in massive batteries. These massive batteries should have a current regulating system( i.e., even if the demand is more the battery with its regulating system will give a constant current only over long periodstill the battery discharges completely).
muralikrishna

13. Sep 22, 2008

### Pumblechook

There is no such thing as excess electricity.

An alternator being spun by a diesel engine for instance produces electricity to feed the load. Reduce the load and the alternator produces less output. The speed doesn't change because the output has to be near to 50 or 60 Hz (depending on where you are in the World) but the diesel engine doesn't have to work so hard and less fuel is used.

However you might say that generating capacity not being used all the time is wasteful and some means of storage could allow it to be used more of the time.

The problem is the scale of the storage systems, inefficiency and the huge cost. It might well be much cheaper to just have generating capacity siting idle for part of the day.

Solar panels also only produce power when demanded by a load. The problem with solar and battery storage is the cost.

14. Sep 22, 2008

### stewartcs

No.

There isn't just one generator supplying the grid. If the demand is lower in the winter, then the generator set is not needed to feed the bus. Take it off-line and conserve fuel. This was my point, which I thought was obvious (apparently it wasn't).

CS

15. Sep 22, 2008

### Pumblechook

Ah well.. Pumblechook is a character from literature who is a bit of a 'know all'.