Saving Energy: 110VAC vs. 220VAC ?

[ataslaki]

I'm sure anyone (but me) her on this forum can answer this basic question, which has bugged me for years .

If a system is powered by 220VAC, are you saving money from usage of electricity over a similar system that runs on 110VAC ?

Similarly, will you be saving money if your system is 480VAC vs. 220VAC?

 

[buzzp]

Probably not. Energy is measured in Watts (Ill keep it simple). Watts is voltage times current. If you have a process it uses some amount of energy to do the work. If the 'process' is held constant then the same amount of power will be needed at 220 as it uses at 110. The difference will be the 220V process will use less current (smaller wire, etc) than the 110V process.
110I=Watts
220I=Watts
If watts is constant (same process) then you can see how the current changes. This is a simple explanation but will do for now.

 

[rbulsara]

Its not really saving of energy or I2R losses that makes higher voltage more attractive. But the fact that higher voltage system will have lesser current for the same power hence uses smaller conductors. Therefore higher voltage system costs much less to install and you do save money.

120V systems like in the USA requires 480V to 208Y/120V stepdown transformers,as 480Y/277 is the norm for commercial/industrial facilities.

Where as 415Y/230V systems do not require step-down transformers. So you do save transformer losses, besides initial the costs.

Also higher voltages have lesser voltage drops and can trasmitt a given power over longer distance for a given size of wire or more power for the same distance, compared to low voltage systems.

Cost is a relative term, what is not a big deal in a relatively prosperous country like USA is a big deal for developing countires or even other developed countries.

 

[jraef]

I could argue about those statements on equipment costs, but it isn't germane. The original question was in regards to ELECTRICITY costs, so buzzp is essentially correct as far as the average user is concerned. There has been some debate as to whether 3 phase motors are more efficient than 1 phase, but since the OP was speaking of 1 phase only, there is no difference in electricity costs. If you had dozens of loads spread out over a large area, the lower line losses from having lower current at the higher voltage might possibly be noticeable, but then again if the wire were big enough you could negate that as well.

"Venditori de oleum-vipera non vigere excordis populi"