Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: zanewiller on 15/04/2022 09:29:09

Title: Is a unit of energy the equivalent, regardless of the way things are delivered?
Post by: zanewiller on 15/04/2022 09:29:09

My house is all electric and when I get my charge, it shows the number of units of power I have utilized. It is at present around 17,000 units per year. I accept that a unit is one kilowatt hour. My inquiry is, is a unit of energy (one kilowatt hour) the equivalent, whether it is delivered by gas or by power? All in all, in the event that my warming was by gas and I kept my home temperatures about the equivalent, could I actually use around 17,000 units whether or not it was provided by gas or power (this may, obviously rely upon the proficiency of the warming framework)? Maybe one more perspective on is find out if heating up a pot of water by gas or electric would utilize similar number of units.

Title: Re: Is a unit of energy the equivalent, regardless of the way things are delivered?
Post by: yor_on on 15/04/2022 10:04:45

If you mean that different fuels contain a different energy content, and final output, converting that to kilowatt of electrical energy? Of course there are differences, and if then including their different pollution quotient per kilowatt.you get to even more differences.
=

Otherwise a kilowatt is one kilowatt, no matter how it came to be.

Title: Re: Is a unit of energy the equivalent, regardless of the way things are delivered?
Post by: Bored chemist on 15/04/2022 10:37:52

If you get a kilowatt hour of energy provided by burning gas some of it goes up the flue.
But that's not the case with electricity.

Quote from: zanewiller on 15/04/2022 09:29:09

Maybe one more perspective on is find out if heating up a pot of water by gas or electric would utilize similar number of units.

Nearly- but the flames round teh pot mainly heat the air, so the losses are bigger.

Title: Re: Is a unit of energy the equivalent, regardless of the way things are delivered?
Post by: vhfpmr on 15/04/2022 15:56:09

Boilers are typically about 90% efficient, so to get 17MWh of heat out you'd need about 18.9MWh of gas in. However the unit price of electricity is about 4.5 times higher, so gas works out a lot cheaper overall. I can heat the whole house with gas for about the same cost as heating one room by electricity.

Title: Re: Is a unit of energy the equivalent, regardless of the way things are delivered?
Post by: alancalverd on 15/04/2022 17:00:15

Quote from: vhfpmr on 15/04/2022 15:56:09

However the unit price of electricity is about 4.5 times higher,

Because a lot of gas is used to make electricity, at around 45% efficiency!

Title: Re: Is a unit of energy the equivalent, regardless of the way things are delivered?
Post by: evan_au on 16/04/2022 08:41:31

Quote from: vhfpmr

I can heat the whole house with gas for about the same cost as heating one room by electricity.

Heating a room with a reverse-cycle airconditioner produces about 3x the heating of an electric heater of the same rating.

You can't run a TV or a smartphone on gas (at least, not efficiently).
- But you could run a TV or smartphone on solar electricity during the day (high initial cost, low running costs).

Title: Re: Is a unit of energy the equivalent, regardless of the way things are delivered?
Post by: yor_on on 17/04/2022 09:44:55

Sorry, wrong thread. Took the comment away.