#### suzuki

Joined Aug 10, 2011
119
Hi,

just a general question about dc and ac loads. Is anyone aware of any statistics that show how much of the energy we produce is used for dc loads compared to ac loads? my gut feeling is that nowadays the number of dc loads is beginning to outnumber ac loads, but it would be nice to see some official data on this. tried a quick google, but couldn't find anything "official"

tia

#### russ_hensel

Joined Jan 11, 2009
825
I doubt it, if you count the power as generated. Almost all is AC, even in cars. DC generators and batteries are quite rare ( by amount of power ). Photo voltaic is DC at generation.

#### suzuki

Joined Aug 10, 2011
119
hi,

Yes, i agree that most of the electricity now is generated and distributed in AC. however, i guess what i am wondering is how much of this ac power is used for dc loads? i think with the increase in companies like google who have huge energy requirements to run their servers (a dc load), the amount of electricity for dc loads has become greater than for ac loads (such as resistive light bulbs)

#### holnis

Joined Nov 25, 2011
49
I don't know about any statistics from that kind. But I think almost all is AC, AC is the standard form of electricity for anything that plugs in to the utility power. Also AC is used for grid service because it is more practical for long distance transmission.

#### BillB3857

Joined Feb 28, 2009
2,569
Sounds like the Edison/Tesla argument. A/C provides an easier means of wide area distribution. Also, it is much easier to convert A/C to DC than the other way around.

#### holnis

Joined Nov 25, 2011
49
Sounds like the Edison/Tesla argument. A/C provides an easier means of wide area distribution. Also, it is much easier to convert A/C to DC than the other way around.
Yes, It is much easier to change the voltage of AC electricity for transmission and distribution.

Also, the cost of plant associated with AC transmission (circuit breakers, transformers.. etc) is much lower than the equivilant of DC transmission.

#### Randy956

Joined May 15, 2007
1
Hi Tia,

If you think about it a bit you will probably come to the conclusion that we require more AC power so it can be converted to DC. Given that, I'd make the general statement that we use more AC than DC. Even battery devices are charged from DC that is converted from AC.

Randy
( I know it's an old thread.. can't help myself )

#### alfacliff

Joined Dec 13, 2013
2,458
but the dc loads are at a lot of diferent voltages. dc does not cheaply or efficently change voltages easily. the google servers mentioned, do they run off of dc supplies? or ac distribution that changes to dc at the point of use? they could run off of a 3 phase buss distribution much easier than if it was a dc supply buss.

Joined Jul 18, 2013
28,012
Long distance power transmission is now done in H.V. DC generated AC and then converted, converted back to AC when it reaches the distribution point. there are far less losses with DC also as well as this reduction there is less cost due to one less conductor, the saving pay for the switching convertors.

On the smaller note, there has been a change in low voltage control from 120vac to low voltage DC.
One of the reasons is that DC inductive components generally have a longer life due to being less prone due to burn out when the armature or moving element does not move to its shifted position.
Max.

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#### ErnieM

Joined Apr 24, 2011
8,362
Is anyone aware of any statistics that show how much of the energy we produce is used for dc loads compared to ac loads?