Hi all!

I was just thinking about the energy bill in a Nepalese house. Gas price --- we can't do anything about it. Its rising high like a balloon filled with hydrogen. Anyway, i was calculating and comparing the electricity bill in a house in America and Nepal.

We know that our circiut in Nepal uses 230 V input voltage and American uses 120 V .

Power = V² /R  Lets say we use a appliance with1000 Ohm in Nepal and America.

IN Nepal,

Power = (230)²/1000 = 52.9 Watt

Amount of Energy in one day (24 Hrs.) = 52.9 *24 = 1269.6 Wh = 1.27 KWh (KiloWattHr)

IN America,

Power = (120)²/1000 = 14.4 Watt

Amount of Energy in one day (24 Hrs.) = 14.4 *24 = 345.6 Wh = 0.345 KWh (KiloWattHr)

IF the electricity rate is $0.10 per KWh

Then, a Nepali pays : $0.10*1.27 = $ 0.127 = 12.7 Cents

And an American pays:  $0.10*0.345 = $ 0.0345 = 3.45 Cents

 

So, Why are we paying expensive electric bill making our voltage 230 Volts? Why dont we make 120 Volts?

Is there anybody to figure this out? OR i am lost here!!

 

a well known formula,

 P=V*I

so,if power for an applience is constant,

  V*I=K(constant)

or,  V ∞1/I

e.g. P=1000W

if V=200V,it will take 5A current

if V=100V,I will be 10 A

therefore,for a device having constant power consumption,if we decrease voltage,it will take more current.and ultimately power consumption will be same.

 

i feel very bad about myself right now, laaz le mukh chopna man lagyo!

uniscom formula is correct. Matter of fact, Lorenzobernini's assumption is wrong, most appliances are rated in Watts and not in Ohms. Therefore, take the example of a 20 Watt bulb.

P = VI

Since P = 20W and V = 230 V (Nepal rating)

Therefore, I = 20/230 = 0.087 A or 87 mA

V = 120 V (American rating)

Therefore, I = 20/120 = 0.167 A or 166.67 mA

Think of current (I) as water, so more the water, bigger the pipe needed. Therefore, more current, thicker conductor required, meaning more copper required. However the trade off is thinner the conductor, more support or poles are required. Since Nepal has more trees (for wooden poles) than copper, 230 V is a cheaper investment for Nepal than 120 V though 120V is likier to be a safer voltage to handle. Nevertheless, the voltage losses in 230 V is insignificant compared 120 V losses.

Futhermore, most asian countries use the 230 V rating. Therefore power distribution equipments (transformer, circuit breakers, generators) of 230 V ratings is more easily available to Nepal than 120 V equipements. That was problably why Nepal most likely choose the 230 V rating.

As for your electric bill comparison, an average American home is likely to consume more power than a home in Nepal. The major reason being, we are having close to 8 hours of load shedding per day for almost three months. With no fuel to power the generators, I think that consumption should be even lesser. Irony of it all, unless you are village with micro hydropower generation plant of your own, you are less likely to be dependent on electricy in Nepal.

I hate physics

I hope you didn’t publish a thesis on this. Going with your assumption, why don’t we just increase ampacity of the cable (increase current) and keep the voltage as low as 1 Volt; won’t it be real cheap? Why go with 120 volts?

Thank God for helpless giving him some help.

Question, don't we have 240 volts instead of 230?

I was wondering is there are any coal mines in Nepal from which we can generate electricity. I was in Wyoming for a trip. and i foud like atleast eight dams from Casper till the boarder of Nebraska. What surprised me that these dams with hydro-electricity generators contributes very less like only 15% to the demand of electricity. They do have quite a few modern wind turbines in use, but still they are highly dependent on coals. This made me thinking "How is the coal situation in our country". Not that i wanna exploit our natural resources and pollute atmosphere more, but just outta cuorosity.

P.S: Not trying to be a SMARTASS. Have a good weekend.

Thanx uniscom and helpless. This stupid Lorenzo was just recalling college physics ... and its been long time. Now I got how it works.

There is one study done by world bank in Nepal, which has concluded that, we can have cheaper, reliable and risk-free electricity from coal plant in Nepal than hydroplant. For this, we need to purchase coal from bihar and build powerplants in biratnagar to birgunj belt. The only problem is the environmental pollution. But, for a poor country like Nepal, environment should not be an issue. Our whole country's pollution level will be less than 5% of Mumbai city even if we line up with coal plant throughout in our terai belt for electricity generation.

one more thing;
    if safety during using electricity appliences is excluded, higher voltage lines are better than lower ones . i mean power supply of 230V is better than 120V. here is the reason:
      from wikkipedia:
  

Electrical power is always partially lost by transmission. This applies to short distances such as between components on a printed circuit board as well as to cross country high voltage lines. The major component of power loss is due to ohmic losses in the conductors and is equal to the product of the square of the current and the resistance of the wire:

For a system which delivers a power, P, at unity power factor at a particular voltage, V, the current flowing through the cables is given by . Thus, the power lost in the lines,

Therefore, the power lost is proportional to the resistance and inversely proportional to the square of the voltage. A higher transmission voltage reduces the current and thus the power lost during transmission.

In addition, a low resistance is desirable in the cable. While copper cable could be used, aluminium alloy is preferred due to its much better conductivity to weight ratio making it lighter to support, as well as its lower cost. The aluminium is normally mechanically supported on a steel core.

  link: http://en.wikipedia.org/wiki/Electric_power_transmission