Tesla V3 Supercharger - 1,000 MPH

[UncleDave]

Originally Posted by edhackett

The EPA number does not take into account the efficiency of the power generation. That varies by power plant type. The average efficiency of U.S. natural gas plants is 45%. Coal is 37%.

The overall efficiency for an EV powered by natural gas would be 26.6-27.9% and 21.8-22.9% for coal.

Ed


So then in the case of a grid like Californias or say a state with a higher % of hydro, Nuke, and renewables it would be a higher % than with just a single fuel plant- correct?

We know without a doubt the EV is more efficient at converting the energy - so then it becomes a matter of the grid source which isnt fixed.

The net effect over time as the grid sources change and becomes more efficient the car becomes more efficient whereas an ice vehicle has relatively fixed efficiency.

Natural gas would NOT be a best case efficiency.

UD

 

[OVERKILL]

Originally Posted by UncleDave
Originally Posted by edhackett

The EPA number does not take into account the efficiency of the power generation. That varies by power plant type. The average efficiency of U.S. natural gas plants is 45%. Coal is 37%.

The overall efficiency for an EV powered by natural gas would be 26.6-27.9% and 21.8-22.9% for coal.

Ed


So then in the case of a grid like Californias or say a state with a higher % of hydro, Nuke, and renewables it would be a higher % than with just a single fuel plant- correct?

We know without a doubt the EV is more efficient at converting the energy - so then it becomes a matter of the grid source which isnt fixed.

The net effect over time as the grid sources change and becomes more efficient the car becomes more efficient whereas an ice vehicle has relatively fixed efficiency.

Natural gas would NOT be a best case efficiency.

UD



That chart is grossly misleading because it just factors in thermal efficiency rather than fuel density. A nuke uses fuel that's 20,000 times more dense than coal, but that's not represented properly, if at all. Thermal steam plants (nuke, gas, coal, oil...etc) all operate within a similar range of efficiency which is around 30-40%. CC gas plants are a bit higher.

To generate a person's lifetime use of energy, which averages 562,500kWh, you would need:
- 292,000kg of coal
- 14.6kg of Uranium

A rather marked difference. That's roughly a popcan sized uranium pellet, with only ~8% of it utilized. In comparison, a typical 5kW solar array will produce 78,840kWh over its 20 year lifespan.

 

[UncleDave]

Originally Posted by OVERKILL
That chart is grossly misleading because it just factors in thermal efficiency rather than fuel density. A nuke uses fuel that's 20,000 times more dense than coal, but that's not represented properly, if at all. Thermal steam plants (nuke, gas, coal, oil...etc) all operate within a similar range of efficiency which is around 30-40%. CC gas plants are a bit higher.

To generate a person's lifetime use of energy, which averages 562,500kWh, you would need:
- 292,000kg of coal
- 14.6kg of Uranium

A rather marked difference. That's roughly a popcan sized uranium pellet, with only ~8% of it utilized. In comparison, a typical 5kW solar array will produce 78,840kWh over its 20 year lifespan.


I understand there is a huge density diff and that nuke are the most dense by a landslide -

The context of why it was there was there is for an efficiency reference vs natural gas.

Do we agree if your grid gets its power from a nuke its more efficient than if it gets it from a natural gas plant?

If we do then we both agree that a natural gas grid to wheel example is NOT best-case scenario for EV efficiency.

UD

 

[edhackett]

Originally Posted by UncleDave

I understand there is a huge density diff and that nuke are the most dense by a landslide -

The context of why it was there was there is for an efficiency reference vs natural gas.

Do we agree if your grid gets its power from a nuke its more efficient than if it gets it from a natural gas plant?

If we do then we both agree that a natural gas grid to wheel example is NOT best-case scenario for EV efficiency.

UD

From a strictly energy efficiency standpoint; energy input to the plant vs electrical power output, nuke is not more efficient that natural gas. A nuke plant is in the same range of efficiency as coal plants, at 33-37%. Natural gas is an average of 45%, making natural gas more efficient.

Here are the energy efficiencies of the major power generation sources and their percent makeup of U.S. power production.

Code
Coal 37% 27.5%

Natural Gas 45% 35.2%

Nuke 33%-37% 19.4%

Hydro(large) 95% 7.0%

Wind ~50% 6.5%

Solar(+inverter) 17% 1.4%

Looking at specific areas, hydro sourced power would be the best case for an EV. Looking at the country as a whole, natural gas comes out ahead when weighted for households served.

Ed

 

[UncleDave]

Originally Posted by edhackett

From a strictly energy efficiency standpoint; energy input to the plant vs electrical power output, nuke is not more efficient that natural gas. A nuke plant is in the same range of efficiency as coal plants, at 33-37%. Natural gas is an average of 45%, making natural gas more efficient.

Here are the energy efficiencies of the major power generation sources and their percent makeup of U.S. power production.

Code
Coal 37% 27.5%

Natural Gas 45% 35.2%

Nuke 33%-37% 19.4%

Hydro(large) 95% 7.0%

Wind ~50% 6.5%

Solar(+inverter) 17% 1.4%

Looking at specific areas, hydro sourced power would be the best case for an EV. Looking at the country as a whole, natural gas comes out ahead when weighted for households served.

Ed


For discussion sake lets throw out the WSJ slide and say its bogus.
Lets also throw out state variability so places like Cali with 1/3 renewables and just look at the US average in your data.

Do we agree - When one averages in 11.9% of much higher efficiency sources (hydro, wind, solar) the EV efficiency will go up vs just NG being soley accounted for ?

Do We agree the electric conversion to forward energy is much more efficient than Internal combustion?

UD

 

[Cujet]

Originally Posted by UncleDave


What is the source of the 29% number using natural gas?

https://www.fueleconomy.gov/feg/evtech.shtml

According to the EPA the EV# is 59-62% from grid to wheels double the number you are quoting.


Today's "ultimate" combined cycle natural gas power plants can reach 63% at the generator terminals, however, they are 50-54% efficient at the power plant fence. Remember some energy is used to run the plant, some power is lost in stepping up the voltage and there are periods of time where peak efficiency is not reached. Today's grid losses are steadily 7% to 8%. The bottom line is that the very best EV's can achieve is 29% in modest climates when powered by fuel.

Don't forget that combined cycle power plants NEED peaker plants to cover excess loads and/or to cover for maintenance down time. That pushes NG consumption WAY up.

Of course, when powered by water, sun, wind or nukes, such numbers don't really matter.

Please don't take this as me "dumping" on EV's. I want a sports car EV badly and will put up with the downsides. But we need to be factual.

 

[Cujet]

Originally Posted by UncleDave


Do We agree the electric conversion to forward energy is much more efficient than Internal combustion?



From base energy source to wheel, I disagree. Prius/CamryH/AccordH engines run 41% efficient (as good as a power plant) and have minimal transmission losses, peaking at 15% loss. Plus they have regenerative braking just like EV's.

While we don't have diesel hybrids here, they exist elsewhere. With engine efficiency at 45%.

But yes, electric motors hover around 90% efficient. They do take what comes out of the motor controller and utilize it efficiently.

Once again, from fuel source to wheel, the best hybrids consume 20% less energy.

 

[UncleDave]

Originally Posted by Cujet
Originally Posted by UncleDave


Do We agree the electric conversion to forward energy is much more efficient than Internal combustion?



From base energy source to wheel, I disagree. Prius/CamryH/AccordH engines run 41% efficient (as good as a power plant) and have minimal transmission losses, peaking at 15% loss. Plus they have regenerative braking just like EV's.

While we don't have diesel hybrids here, they exist elsewhere. With engine efficiency at 45%.

But yes, electric motors hover around 90% efficient. They do take what comes out of the motor controller and utilize it efficiently.

Once again, from fuel source to wheel, the best hybrids consume 20% less energy.


No dumping sensed - just a group of guys talking/ typing.

From base source to wheel everywhere- or on average? Even in California where 1/3 of the energy comes from renewables ?

Can you share your data so I can check it out? I'm always interested to know the facts and see who did the work to establish them as such.

UD

 

[JeffKeryk]

I don't pretend to understand all the numbers.
Cujet - question for you:
Why do you include energy production numbers for a Tesla and not for an ICE car?
It seems to me the the cost to get fuel to Costco for me to pump costs quite a bit...

If sending me a site for an explanation is possible, I would appreciate that.

Of course the cost for PGE to burn down CA ain't exactly cheap either...
Again, just a question. All good.

 

[OVERKILL]

Originally Posted by UncleDave
Originally Posted by OVERKILL
That chart is grossly misleading because it just factors in thermal efficiency rather than fuel density. A nuke uses fuel that's 20,000 times more dense than coal, but that's not represented properly, if at all. Thermal steam plants (nuke, gas, coal, oil...etc) all operate within a similar range of efficiency which is around 30-40%. CC gas plants are a bit higher.

To generate a person's lifetime use of energy, which averages 562,500kWh, you would need:
- 292,000kg of coal
- 14.6kg of Uranium

A rather marked difference. That's roughly a popcan sized uranium pellet, with only ~8% of it utilized. In comparison, a typical 5kW solar array will produce 78,840kWh over its 20 year lifespan.


I understand there is a huge density diff and that nuke are the most dense by a landslide -

The context of why it was there was there is for an efficiency reference vs natural gas.

Do we agree if your grid gets its power from a nuke its more efficient than if it gets it from a natural gas plant?

If we do then we both agree that a natural gas grid to wheel example is NOT best-case scenario for EV efficiency.

UD


Yes, we are in agreement on that point.

 

[OVERKILL]

Originally Posted by edhackett
Originally Posted by UncleDave

I understand there is a huge density diff and that nuke are the most dense by a landslide -

The context of why it was there was there is for an efficiency reference vs natural gas.

Do we agree if your grid gets its power from a nuke its more efficient than if it gets it from a natural gas plant?

If we do then we both agree that a natural gas grid to wheel example is NOT best-case scenario for EV efficiency.

UD

From a strictly energy efficiency standpoint; energy input to the plant vs electrical power output, nuke is not more efficient that natural gas. A nuke plant is in the same range of efficiency as coal plants, at 33-37%. Natural gas is an average of 45%, making natural gas more efficient.

Here are the energy efficiencies of the major power generation sources and their percent makeup of U.S. power production.

Code
Coal 37% 27.5%

Natural Gas 45% 35.2%

Nuke 33%-37% 19.4%

Hydro(large) 95% 7.0%

Wind ~50% 6.5%

Solar(+inverter) 17% 1.4%

Looking at specific areas, hydro sourced power would be the best case for an EV. Looking at the country as a whole, natural gas comes out ahead when weighted for households served.

Ed


Yes, as I mentioned, thermal plants (save combined cycle gas plants, which are a bit higher) are all roughly the same efficiency in terms of using steam to run a turbine. The difference comes when one looks at what's used to make that steam, as I also covered. If we are looking at volume of fuel consumed to produce that steam, the nuke comes out ahead by an absolutely ridiculous margin. It takes an obscene amount of natural gas (17,500 cubic meters) to produce the same amount of electricity as 1kg of uranium, regardless of the lower efficiency in the steam turbine phase.

If we are looking for the "best case" scenario, it depends on how you want to define that. Nukes, hydro, wind and solar are all low emissions sources. The lowest of the group is wind at 11gCO2/kWh, followed immediately by nuclear at 12gCO2/kWh, then hydro at 24gCO2/kWh then solar at 45gCO2/kWh. These are all lifetime emissions. Of course a nuke and hydro don't require a backup gas plant and have much higher capacity factors, so ultimately from a grid perspective, they would have lower emissions than wind.

If we look at Ontario, which is presently 23gCO2/kWh, charging a car here right now has a minuscule benefit over charging one in Quebec, whose basically entire grid is hydro and thus 24gCO2/kWh. Charging one in California, you are looking at 313gCO2/kWh at this time.

 

[UncleDave]

How much energy from mine to plant is spent in processing/ enrichening that 1KG of uranium in terms of energy and effort expended to prepare the fuel for use?

Then ongoing costs to maintain a plant would be significant as well (Id guess)

Wouldn't leaving that out of any efficiency equation be as equally misleading as failing to consider energy density in an efficiency equation?

Id guess (it is just a guess) the energy efficency slide the SWJ posted included most of these ancillary costs.




UD

 

[Cujet]

Originally Posted by JeffKeryk

Cujet - question for you:
Why do you include energy production numbers for a Tesla and not for an ICE car?


I don't include the energy production numbers in either case. Natural Gas production, digging for Coal, or mining Uranium and Oil/Gasoline production does take some energy. Whether we drill and frack the Marcellus Shale or drill for oil in West Texas, both energy production expenditures are a small percentage of the yield.

Nor do I include the substantial energy expenditure and CO2 emissions in the production of Lithium Batteries.

I am only concerned with the BTU consumed to go a mile. When powered by fuel, hybrids consume less per mile than EV's, as there are far fewer input to output losses.

FURTHERMORE, solar/wind in locations without sufficient backup hydro gen power have not been shown to reduce electrical generation FUEL consumption. As inefficient peaker plants are necessary to cover the intermittent nature of renewable energy.

 

[OVERKILL]

Originally Posted by UncleDave
How much energy from mine to plant is spent in processing/ enrichening that 1KG of uranium in terms of energy and effort expended to prepare the fuel for use?

Then ongoing costs to maintain a plant would be significant as well (Id guess)

Wouldn't leaving that out of any efficiency equation be as equally misleading as failing to consider energy density in an efficiency equation?

Id guess (it is just a guess) the energy efficency slide the SWJ posted included most of these ancillary costs.




UD


It's all captured by the gCO2/kWh figure, that's total lifecycle emissions including mining, enrichment...etc. This is why wind and nuclear have roughly the same environmental footprint, despite wind not having on-site backup diesel generators (the gas plant to back it up isn't included) or required mining of fuel. On the other hand, a coal plant, while having fewer staff, is similarly burdened by the footprint of those ancillary activities (minus the on-site diesels though). This is also why solar, which has no direct emissions, has a significantly higher footprint than wind, nuclear or hydro. Its extremely low density doesn't do near as well in offsetting the footprint of its production.

When you are dealing with a fuel sources that is 20,000 times more dense, getting that fuel from ground to unit ultimately makes up a VERY small portion of the overall footprint of the plant. When you consider that the fuel is then in place for up to 2 years in most PWR's, versus having to be constantly fuelled like a gas, oil or coal plant, it helps put that into perspective.

For a Canadian nuke (CANDU) there is no enrichment phase. Natural uranium is put into pellets, which are assembled into bundles and used directly in the reactor. The downside of no enrichment is a shorter fuel bundle life. This ends up still being slightly in favour of the NU fuel (lower footprint) though, but for the purposes of the IPCC it's a wash and the cited figure (12gCO2/kWh) is used generically across plants.

 

[UncleDave]

I'd like to know how in-depth that report gets, but I cant find a copy of that report, just references.


UD

 

[OVERKILL]

Originally Posted by UncleDave
I'd like to know how in-depth that report gets, but I cant find a copy of that report, just references.


UD


It gets pretty in-depth, but it does cite reference material, which you'd also have to review if you want to see all the externalities.

Full document can be found here: https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_chapter7.pdf

Some key excerpts:

Originally Posted by IPCC Report
When assessing the potential of different mitigation opportunities, it is important to evaluate the options from a lifecycle perspective to take into account the emissions in the fuel chain and the manufacturing of the energy conversion technology (Annex II.6.3). This section contains a review of life-cycle GHG emissions associated with different energy supply technologies per unit of final energy delivered, with a focus on electricity generation (Figure 7.6).


Originally Posted by IPCC Report
For RE, emissions are mainly associated with the manufacturing and installation of the power plants, but for nuclear power, uranium enrichment can be significant (Warner and Heath, 2012). Generally, the ranges are quite wide reflecting differences in local resource conditions, technology, and methodological choices of the assessment. The lower end of estimates often reflects incomplete systems while the higher end reflects poor local conditions or outdated technology.


Originally Posted by IPCC Report
The literature reviewed in this section shows that a range of technologies can provide electricity with less than 5% of the lifecycle GHG emissions of coal power: wind, solar, nuclear, and hydropower in suitable locations. In the future, further reductions of lifecycle emissions on these technologies could be attained through performance improvements (Caduff et al., 2012; Dale and Benson, 2013) and as a result of a cleaner energy supply in the manufacturing of the technologies (Arvesen and Hertwich, 2011).

 

[UncleDave]

Great reading, pretty sure this is a diff report than what the WSJ references.....

Thanks in any case Ill absorb.

UD

 

[OVERKILL]

You are quite welcome! And yes, I don't think the WSJ chart is based on this. I like to defer to the IPCC data whenever possible as I feel its the most complete representation of the subject matter. Power generation, in particular nuclear, is a bit of a hobby of mine, so I have a fair bit of data stashed away on some of this stuff.

 

[pschnahc]

Hydrocarbons are still the superior energy source, I see

 

[kschachn]

Originally Posted by pschnahc
Hydrocarbons are still the superior energy source, I see

You're new here? So the Ben Jungle is a real location in Canada?