Marginal power

[JRP3]

First, in CA, coal is not used dispatch (according to the study, which understands very well "marginal cost"). Specific flavors of NG, and other sources, are used. The flavors at night are better for EV charging.

Then, what you are confusing is that I am not talking about plugging in an EV during the day at all. I'm merely talking about using solar to produce electricity, independent of EV charging (which happens at a different time). I'm saying that the fact that solar peaks during the day is great, because the generation it replaces at that time has a higher gCO2/kWh.

Sure, so you admit that the use of solar in the grid is completely independent of EV use, and whatever emission reduction is involved has no impact on the demand from EV charging. Focusing on CA only then night time EV charging will increase grid emissions from NG, and looking at the country as a whole night time EV charging will increase grid emissions from NG and coal. Which is all I've been saying this whole time.

 

[Norbert]

Sure, so you admit that the use of solar in the grid is completely independent of EV use, and whatever emission reduction is involved has no impact on the demand from EV charging. Focusing on CA only then night time EV charging will increase grid emissions from NG, and looking at the country as a whole night time EV charging will increase grid emissions from NG and coal. Which is all I've been saying this whole time.

I don't have to "admit" that, since I didn't claim anything else. You are still confusing things.

However you said that EVs should be charged during the day, if you want to avoid coal use at night. Yet in CA, charging during the day does not avoid coal use, even though there is coal being used at night. So it turns out to be better to charge at night, even from an individual-use CO2 point of view.

 

[JRP3]

Your post that I quoted stated that CA does not use coal. Also, you were the one who brought up solar input, when it has no relevance to the marginal load discussion. Maybe it's just me but you aren't making much sense at this point.

 

[Norbert]

Your post that I quoted stated that CA does not use coal. Also, you were the one who brought up solar input, when it has no relevance to the marginal load discussion. Maybe it's just me but you aren't making much sense at this point.

Coal is used in CA both day and night, but not ramped up or down when the load on the grid changes, or to be exact, not in a way that one would notice in the numbers.

There are three conclusions I draw from the study (assuming that it is correct, it seems well-researched). These are somewhat independent of each other, but all result from examining "marginal emissions", meaning, emissions resulting from the effects of adding additional load, at a specific point. (Which implies blaming EVs for things they are not really responsible for.)

1. The time at which charging an EV causes the least amount of additional CO2, is between 2 am and 4 am (California average). (Regardless of other reasons to charge at night.)

2. Any EV charging at that time will apparently produce less additional CO2 than a Prius. (And EVs charging at other times not really that much more than that). The CO2 values at ~3am are, I think, good even for NG, and better than grid overall average (at least around 2007).

3. Examining which power plants are being ramped up and down during the day, also shows that solar peaks at a time at which marginal emissions are higher that usual, so solar has a higher benefit in reducing CO2 than it would have if it peaked at some other time. (Which has nothing directly to do with EVs, except that having an EV might motivate you to buy solar, and that both support for EVs, and support for solar, are results of a pro-environmental development in general).

 

[Robert.Boston]

Taking a closer look at the PJM shutdowns, it looks as if most of them are simply temporary closings to allow upgrades to be done to them, not actual permanent shut downs.

No; these deactivations listed in the PJM link are permanent -- in theory, you can simply mothball a deactivated unit, rather than retiring it, but that's not what's happening with any of the coal units listed there. (Most of these generation owners are clients of mine, so I'm very confident of this answer.)

 

[Robert.Boston]

Taking a closer look at the PJM shutdowns, it looks as if most of them are simply temporary closings to allow upgrades to be done to them, not actual permanent shut downs.

No; these deactivations listed in the PJM link are permanent -- in theory, you can simply mothball a deactivated unit, rather than retiring it, but that's not what's happening with any of the coal units listed there. (Most of these generation owners are clients of mine, so I'm very confident of this answer.) There will be additional, multi-month shutdowns at most other coal plants while they install the environmental control equipment required by MATS and CSAPR.

 

[JRP3]

No; these deactivations listed in the PJM link are permanent -- in theory, you can simply mothball a deactivated unit, rather than retiring it, but that's not what's happening with any of the coal units listed there. (Most of these generation owners are clients of mine, so I'm very confident of this answer.) There will be additional, multi-month shutdowns at most other coal plants while they install the environmental control equipment required by MATS and CSAPR.

I don't understand this statement which I see repeated often:

Reliability Analysis complete - impacts identified - upgrades scheduled to be completed by June 2015. Thus generator can be allowed to deactivate as scheduled.

Why would they upgrade a plant that is scheduled to be shut down? Also, a number of them say this:

Reliability Analysis complete - impacts identified - upgrades scheduled to be completed by June 2015.

 

[Norbert]

There will be additional, multi-month shutdowns at most other coal plants while they install the environmental control equipment required by MATS and CSAPR.

I was wondering whether some coal plants might get improved to almost NG level (in terms of CO2 and/or other emissions), but it seems that is in general too costly with NG cost coming down, for example.

 

[stopcrazypp]

Any new load has to be from dispatchable generation. Yes technically your heater demand is probably going to be met with NG or coal, just as your EV is.

I guess my argument completely flew over your head. Okay let's say both the heater and the EV counts as marginal demand (so far all the usage in MY house would count as marginal demand for no apparent reason). Then what DOESN'T. That's my point. What is the demand that gets assigned to the other methods of generation at night (wind, hydro, nuclear, etc)? Why are we not assigning the power plant mix equally to all appliances and households (because that is how the grid responds in the first place)? What criteria are we using to determine what qualifies as marginal and what doesn't? There has to be SOME load that's using the other generation.

 

[JRP3]

I guess my argument completely flew over your head.

Possibly, but you seem to be saying the general grid mix needs to be applied to all demand, even new demand. I understand that point, I'm just not sure it applies. Let's say a new house is built in your neighborhood. You can say it's average power usage is from the grid mix, but the reality is that no new nuclear or hydro comes on line to compensate, but coal and/or NG does, and grid emissions increase accordingly. Yes we would generally consider it's power to be from the average grid mix, but the increase in emissions from it's existence would be only from sources that can increase output. Substitute new EV for new house and you have a similar new load on the grid. (When I say new I mean previously not existing, not just new in that instance. )

 

[Norbert]

You can say it's average power usage is from the grid mix, but the reality is that no new nuclear or hydro comes on line to compensate, but coal and/or NG does, and grid emissions increase accordingly.

Excuse me, the *reality* is that wind and solar and thermal solar come online to more than compensate. But they categorize that away as some "independent action", since you could do one without the other. The reality, however, is that we are not doing one without the other.

 

[dsm363]

JRP3: Your argument applies to any new device, house, building, factory... etc. Only way to accomplish not turning on coal or NG in those instances would be to never build anything or buy anything new. Bottom line is we need to clean up the grid. EVs, on average, are cleaner than average ICEs by a wide margin.

 

[JRP3]

Excuse me, the *reality* is that wind and solar and thermal solar come online to more than compensate.

Not in most of the country. If CA is installing PV and solar thermal at a faster rate than EV purchases as a response to that added demand then that does potentially change the equation, in CA, and I have argued that solar car ports at work can compensate for some of the added demand and would not be built without a fleet of EV's to use them. Part of the problem is you are only focusing on CA and I'm looking at the country in general. Yes CA has more EV's than anywhere else, and I've used that same argument.

 

[JRP3]

Bottom line is we need to clean up the grid. EVs, on average, are cleaner than average ICEs by a wide margin.

Agree completely, and I also point out that comparing all EV's only to a Prius, as if that is always the alternative choice, is misleading at best.

 

[Norbert]

Not in most of the country.

But in CA. Now don't let that keep you from answering stopcrazypp's post, that's still open. (EDIT: Wind power national average is 3.9%, and you need to modify your argument to reflect those conditionals, national average of coal went from 47% to 38%, according to RB to be expected more or less without rebounding).

 

[stopcrazypp]

Possibly, but you seem to be saying the general grid mix needs to be applied to all demand, even new demand. I understand that point, I'm just not sure it applies. Let's say a new house is built in your neighborhood. You can say it's average power usage is from the grid mix, but the reality is that no new nuclear or hydro comes on line to compensate, but coal and/or NG does, and grid emissions increase accordingly. Yes we would generally consider it's power to be from the average grid mix, but the increase in emissions from it's existence would be only from sources that can increase output. Substitute new EV for new house and you have a similar new load on the grid. (When I say new I mean previously not existing, not just new in that instance. )

So your criteria is what is installed first. If that's the case, then the only way you can determine what qualifies as marginal is to have the installation order of all the appliances at the specific moment in time that you are charging your EV. And there is no guarantee that your EVSE is going to be the one near the end of the list, esp. if it has been installed for a couple of years already (there's always new appliances that get installed). Keep in mind not every older appliance is on at the same time your EVSE is on and that old appliances get retired daily. Without the data on instantaneous installation order you can not say that the EVSE is the marginal load without arbitrary assigning it as such.

Put in other words there's going to be certain points in time (low demand) where the EVSE is old enough to be covered by existing non-coal/NG capacity. In times of higher demand, then the EVSE may still fall under non-coal/NG capacity if there are older appliances that have not been turned on.

 

[Robert.Boston]

I don't understand this statement which I see repeated often:

Why would they upgrade a plant that is scheduled to be shut down? Also, a number of them say this:

Reliability Analysis complete - impacts identified - upgrades scheduled to be completed by June 2015.

The "upgrade scheduled" is to the transmission system, not to the plant.

 

[JRP3]

Why upgrade the transmission system to a plant that is shutting down?

 

[JRP3]

Put in other words there's going to be certain points in time (low demand) where the EVSE is old enough to be covered by existing non-coal/NG capacity. In times of higher demand, then the EVSE may still fall under non-coal/NG capacity if there are older appliances that have not been turned on.

Sure, at some point in time a certain amount of charging EV's probably will be covered by an expanded base load power supply. With enough EV's on the road there will always be an EV charging somewhere at some time so a certain portion of the fleet load will be considered base load. But consider this, I have an electric hot water heater on a night time use timer. It's probably 10 years old, so I guess we can consider it as an established load on the grid. When it comes on in the middle of the night what power source is increased to compensate? Obviously not solar, unless the wind happens to pick up when it turns on it's not wind, if it's hydro then that hydro can not be backed up for daytime use when it's more valuable, so it's probably going to be NG or coal.

 

[Norbert]

Something that irritated me a bit, was that some anti-EV articles argue that coal is being used for marginal power because it has a higher marginal cost. Yet at the same time, they argue coal is going to stay because it is cheaper than NG, and that even after NG plants have been built. Maybe I'm missing something there, but I wonder.