kwh @ wall, vs reported

[solar_dave]

That is about 78% efficiency. When you say "conditioning" do you mean preconditioning? If no preconditioning, what is the efficiency?
Or maybe you mean the battery TMS during charging...

No just the TMS, no precondioning included. And yes 78% is about right.

[bronco7TX]

There's a couple other guys here who's posts make me real suspicious of what their day jobs are, too.
Even a quick Google search will show losses of 6.5%. Even that data is a bit dated. I think today it's under 6%, and that's likely considering everything from the power plant to your plug.

I work in the transmission planning department at the Independent System Operator for the New England power grid and the number we use is 8% from generator station to customer meter. Roughly 2.5% losses are on the high voltage transmission system (69kV to 345kV) and 5.5% for distribution losses (69kV all the way down to 240V).

[JMatt]

I work in the transmission planning department at the Independent System Operator for the New England power grid and the number we use is 8% from generator station to customer meter. Roughly 2.5% losses are on the high voltage transmission system (69kV to 345kV) and 5.5% for distribution losses (69kV all the way down to 240V).

The 2.5% transmission sounds right. I don't know much about distribution. I thought 4% or less for that chunk too, but I'd assume you've got accurate numbers for that.

Incidentally, I've toured the control room at ISO-NE before.

[Koz]

No just the TMS, no precondioning included. And yes 78% is about right.

22% charging loss seems awfully high. Is that at or about 70 degrees F? The battery shouldn't be any worse than 8% and the charger loses a few. Where is the rest lost?

[jeffhre]

I work in the transmission planning department at the Independent System Operator for the New England power grid and the number we use is 8% from generator station to customer meter. Roughly 2.5% losses are on the high voltage transmission system (69kV to 345kV) and 5.5% for distribution losses (69kV all the way down to 240V).

Is that true when longer distances are included, considering the breadth of your coverage area? And what about losses at less than 30kV before the power reaches the high voltage transmission system. I'm obviously in favor of using electricity for propulsion, but I would like very much to work on not having my bias lead to putting out false information.

[solar_dave]

22% charging loss seems awfully high. Is that at or about 70 degrees F? The battery shouldn't be any worse than 8% and the charger loses a few. Where is the rest lost?

Well I have actually measured it with the TED, it is what it is. BTW typical loses for lead acid off grid systems is 25% or more depending on the battery. So with charger conversion to DC, thermal management system and battery inefficiency, 22% is actually pretty good.

[JMatt]

Is that true when longer distances are included, considering the breadth of your coverage area? And what about losses at less than 30kV before the power reaches the high voltage transmission system. I'm obviously in favor of using electricity for propulsion, but I would like very much to work on not having my bias lead to putting out false information.

Look at it this way: It reported takes 6 kwh of electricity just to get one gallon of gasoline into your car. (http://gatewayev.org/how-much-electr...on-of-gasoline) (Although I've seen estimates of 7 kwh as well). I'm consuming 32 kwh per 100 miles. If we divide that by a 92% efficiency of the transmission and distribution electric grid, we get 35 kwh - at the generator - per 100 miles driven. Doing the same with a 33.3 mpg car, we get 6 kwh times 3 per 100 miles, divided by efficiency of the electric grid, or about 20 kwh of electricity consumed, just to get the 3 gallons of gas in the tank. So by using an EV we burn an EXTRA 15 kwh of electricity per 100 miles instead of 3 gallons of gas.

So even if you assume the worst, "burning" electrons is roughly equal to getting 225 mpg while burning gasoline.

[tboult]

Look at it this way: It reported takes 6 kwh of electricity just to get one gallon of gasoline into your car. (http://gatewayev.org/how-much-electr...on-of-gasoline) (Although I've seen estimates of 7 kwh as well). I'm consuming 32 kwh per 100 miles. If we divide that by a 92% efficiency of the transmission and distribution electric grid, we get 35 kwh - at the generator - per 100 miles driven. Doing the same with a 33.3 mpg car, we get 6 kwh times 3 per 100 miles, divided by efficiency of the electric grid, or about 20 kwh of electricity consumed, just to get the 3 gallons of gas in the tank. So by using an EV we burn an EXTRA 15 kwh of electricity per 100 miles instead of 3 gallons of gas.

So even if you assume the worst, "burning" electrons is roughly equal to getting 225 mpg while burning gasoline.

The cited article is not quite correct in its interpretation of the numbers. (The quoted letter is better) The 6kwh is the difference in energy input verses the energy in the gallon of gas. It includes input electricity but also includes losses from uncaptured hydrocarbons (e.g. gases that are burned off during cracking), and uses of other sources of energy (e.g. natural gas is commonly used as is steam ). Of the 6-8kw per gallon only about 10% of that is actually electricity. See
http://www1.eere.energy.gov/industry...ng_roadmap.pdf
for a discussion of the energy used in refining.

[JMatt]

The cited article is not quite correct in its interpretation of the numbers. (The quoted letter is better) The 6kwh is the difference in energy input verses the energy in the gallon of gas. It includes input electricity but also includes losses from uncaptured hydrocarbons (e.g. gases that are burned off during cracking), and uses of other sources of energy (e.g. natural gas is commonly used as is steam ). Of the 6-8kw per gallon only about 10% of that is actually electricity. See
http://www1.eere.energy.gov/industry...ng_roadmap.pdf
for a discussion of the energy used in refining.

Agreed. I should have said 6 kwh of "energy" not "electricity."

[jeffhre]

Look at it this way: It reported takes 6 kwh of electricity just to get one gallon of gasoline into your car. (http://gatewayev.org/how-much-electr...on-of-gasoline) (Although I've seen estimates of 7 kwh as well). I'm consuming 32 kwh per 100 miles. If we divide that by a 92% efficiency of the transmission and distribution electric grid, we get 35 kwh - at the generator - per 100 miles driven. Doing the same with a 33.3 mpg car, we get 6 kwh times 3 per 100 miles, divided by efficiency of the electric grid, or about 20 kwh of electricity consumed, just to get the 3 gallons of gas in the tank. So by using an EV we burn an EXTRA 15 kwh of electricity per 100 miles instead of 3 gallons of gas.

So even if you assume the worst, "burning" electrons is roughly equal to getting 225 mpg while burning gasoline.

I've agreed w/ 6kWh of energy, minimum 2kWh of electricity at Louisiana's most updated and efficient refinery plus energy from feedstocks, and rising to about 4kWh of electricity per gallon depending on refinery location. Therefore using 6kWh, your equation denotes total energy used, not kWh of electricity per 100 miles or 3 gallons of gasoline.

However, I am more interested in tapping your experience and expertise in finding up to date numbers for losses during transmission and distribution.