California 2009 Power Mix

jcesare · Apr 28, 2011

Here is the total system power for 2009 by fuel type.
http://energyalmanac.ca.gov/electricity/total_system_power.html

8.1% coal
9.2% hydro
11.6% renewables
13.2% nuclear
42.2% natural gas

planet4ever · Apr 28, 2011

Two comments and a question:

If I remember correctly, most of that imported coal-based power is for one southern California utility, maybe LA DWP? You guys down there should put some pressure on them.
I'm sure that solar power is contributing a lot more than the table shows. The problem is that no one has a way to measure power that never goes through the utility meters. That's the case with nearly 2/3 of the power we use at our home.
So what is all that "Unspecified source" power and where is it entering the system? It and the coal import is really dragging down all the greener in-state averages.

Ray

Stoaty · Apr 28, 2011

planet4ever said:
If I remember correctly, most of that imported coal-based power is for one southern California utility, maybe LA DWP? You guys down there should put some pressure on them.

LA DWP is at about 39% of power from coal. Surprisingly, I believe they are trying to get off coal by 2020. They have increased renewables enough to meet the 20% goal (for 2010, I think). Plans to divest ownership of one of the coal plants in Arizona around 2014. So, progress is being made.

lemketron · May 28, 2011

planet4ever said:
I'm sure that solar power is contributing a lot more than the table shows. The problem is that no one has a way to measure power that never goes through the utility meters. That's the case with nearly 2/3 of the power we use at our home.

I'm not sure it's a "lot" more, but this is a very interesting point that I've never considered, even though I've had solar panels on my roof for eight years now.
I guess the solar figure quoted in those tables will only ever show large-scale solar generation, as opposed to the power generated (and used) locally by homeowners.

Seems like they should (at least in CA, based on CEC rebates paid out) be able to track how many solar systems have been installed. In fact, since they pay by CSI KW rating, they should also have a pretty good idea of how much power is being generated by all those systems as well. Anyone know if this information is available anywhere?

DaveEV · May 28, 2011

lemketron said:
planet4ever said:

I'm sure that solar power is contributing a lot more than the table shows. The problem is that no one has a way to measure power that never goes through the utility meters. That's the case with nearly 2/3 of the power we use at our home.

Click to expand...

I'm not sure it's a "lot" more, but this is a very interesting point that I've never considered, even though I've had solar panels on my roof for eight years now.
I guess the solar figure quoted in those tables will only ever show large-scale solar generation, as opposed to the power generated (and used) locally by homeowners.

Yep - net metered customers aren't counted - not sure what it takes to be counted - you probably have to be a commercial entity who has a PPA to sell electricity to the utility.

lemketron said:
Seems like they should (at least in CA, based on CEC rebates paid out) be able to track how many solar systems have been installed. In fact, since they pay by CSI KW rating, they should also have a pretty good idea of how much power is being generated by all those systems as well. Anyone know if this information is available anywhere?

All the data on existing and even pending installs is on http://gosolarcalifornia.org/ where you'll see that there has been nearly 90,000 projects installed and nearly 900 MW of PV (CEC-AC rating) installed.

For sure they know pretty closely how much electricity is generated due to PV...

planet4ever · May 28, 2011

I'm not sure how much energy California PV systems can generate as an average over the whole state, but I would think that 900 MW of capacity should be able to produce something like 1200 to 1500 GWh per year. (Locally, estimates are about 1.6 mWh/year for each kW installed.) That's nearly twice the 850 GWh reported in the original reference.

To be fair, I am comparing 2009 energy reported with 2011 capacity installed, but I think the most telling statistic in the capacity report is that 29.8% of the capacity is residential. It may indeed be true that the 2009 system power report included most if not all large scale installations, but look at these numbers I just calculated from the 2011 capacity report:

004.84 kW average residential application
138.48 kW average commercial application
198.80 kW average government/non-profit application

If I look at the 645 MW non-residential and multiply by 1600 I get 1033 GWh. Assuming my multiplier is probably off by a bit, and that there has been significant growth since 2009, that matches the reported 850 GWh pretty closely.

Conclusion: they are not counting the residential installations, as I originally hypothesized. I'll leave it up to others to decide whether 30/70 = 43% increase is "a lot more" as I claimed, and whether an extra 400+ GWh/year is "a lot more".

Ray

EricH · May 29, 2011

Why aren't residential solar installations' kWh "counted"?

Because residential solar panels aren't separately metered. The whole point of Net Energy Metering is that the utility has no visibility as to whether you used 900 kWh and generated 500 kWh to offset that -- they would only see the 400 "net" usage. Thus, there's no way to show how much power the panels produced. Larger-scale solar plants are metered so the utility and the generator both know how to settle the payment for the power.

ElectricVehicle · May 29, 2011

Just to add to "the mix":

Some CA utilities are much dirtier / cleaner than others. It also depends on how you value each type of power generation. At any rate, PG&E is only 1% Coal snd they've got Renewable up to 14%. Now I do wish we knew what the 15% "Unspecified" is, since what that really is can affect the picture dramatically. Ok, now I'm getting the eeby-geebies! I doubt there's anything seriously sinister in that 15% "Unspecified", but PG&E should be able to keep better records than that and make sure it's suppliers also do so!

1.3% coal
13.0% large hydro
14.4% renewables (such as wind, geothermal, biomass and small hydro)
20.5% nuclear
34.6% natural gas
1.2% other fossil-based resources
15.0% unspecified

PG&E 2009 Power Mix (from a bill insert)
http://www.pge.com/myhome/environment/pge/cleanenergy/

hill · May 30, 2011

planet4ever said:
Two comments and a question:

If I remember correctly, most of that imported coal-based power is for one southern California utility, maybe LA DWP? You guys down there should put some pressure on them. . . . . . . . . snip

aahhh ... if only life were so simple. If we need extra power in CA ... and have AZ supply it ... and AZ builds a coal fired plant to meet those long term contracts ... good luck with breaching that contract.

DaveEV · May 30, 2011

hill said:
aahhh ... if only life were so simple. If we need extra power in CA ... and have AZ supply it ... and AZ builds a coal fired plant to meet those long term contracts ... good luck with breaching that contract.

Typically those long term contracts are actually investments by the utility meaning they are part owners of the plant - so they can divest in those plants - which LADWP is working on doing.

JeffN · May 30, 2011

PG&E says their average CO2 emission is .524 pounds per kWh. I'm not aware of any more specific breakdown of that number into off-peak or partial-peak values.

Some say that marginal rather than average generation fuel source is a better model for how the charging of EVs will change utility emissions.

I'm not aware of any marginal generation numbers for PG&E but there is a published marginal CO2 equivalent emissions rate for California overall. That value comes from the CARB Low Carbon Fuel Standard regulatory process. Their marginal rate is .831 pounds per kWh. There is some controversy about that number because it includes renewable fuel sources and some say that California's marginal generation will effectively come from natural gas alone.

I don't have an exact reference handy for NG CO2 generation emissions but it is approximately 1.3 pounds per kWh for the 40% expected efficiency of a typical CA NG marginal generation plant.

Gasoline emits about 20 pounds of CO2 per gallon but if you include indirect well-to-wheel emissions for CA formulation gasoline it is about 25 pounds according to CARB.

The EPA rates the Leaf's combined energy usage as 34kWh per 100 miles or 2.94 miles per kWh. Many of us will do better than that in CA.

The result is that the Leaf and similar EVs will emit approximately the following pounds of CO2 equivalent global warming gasses on grid power for every 100 miles:

18 PG&E average
28 LCFS marginal
45 natural gas marginal

50 2011 Toyota Prius
90+ typical mid-size conventional car

And, of course, no oil is harmed in the production of CA grid power.

Sources:
http://www.pge.com/includes/docs/pdfs/about/environment/calculator/assumptions.pdf
http://www.arb.ca.gov/fuels/lcfs/010611lcfs_lutables.pdf
http://www.arb.ca.gov/fuels/lcfs/lcfs.htm
http://www.arb.ca.gov/fuels/lcfs/022709lcfs_elec.pdf
http://pubs.its.ucdavis.edu/publication_detail.php?id=1362

planet4ever · May 30, 2011

Thanks for all the data! Wouldn't the marginal numbers apply only if you were charging your LEAF in the afternoon? I do virtually all of my charging during off-peak hours. I seem to remember reading that natural gas generation can be dialed up or down fairly easily, while nuclear cannot. It would seem like large hydro would also be easy to moderate, though perhaps not. In any event, I would guess that off-peak generation might be more heavily weighted toward nuclear, hence I would expect lower numbers off-peak than the PG&E average.

Ray

EricH · May 30, 2011

planet4ever said:
Wouldn't the marginal numbers apply only if you were charging your LEAF in the afternoon? I do virtually all of my charging during off-peak hours. I seem to remember reading that natural gas generation can be dialed up or down fairly easily, while nuclear cannot. It would seem like large hydro would also be easy to moderate, though perhaps not.
Ray

Generating stations are dispatched in order of economics, which means generally their marginal operating (read: fuel) costs. Thus, hydro and solar have fuel costs of zero and are always on, and nuclear fuel makes up such a minor portion of overall cost that it may as well be "free" for purposes of this calculation. Nuclear in the U.S. is considered "baseload" capacity; the plants run full-tilt as long as they are able.

The marginal plants in California that provide the "next" kWh are virtually 100% natural-gas fired; coal and fuel oil are illegal in CA. So anytime you think of flipping a switch, you are causing a gas-fired plant somewhere in CA to ramp up just a bit. It's possible that CA is importing extra hydropower from Oregon or British Columbia at that moment, but marginal pricing is nearly always set by the least-efficient gas plant that was just dispatched.

ElectricVehicle · May 30, 2011

Don't forget that EV owners start to ask "Where does my electricity come from and what's the impact?" That search often results in EV owners installing Solar Electric (PV), or signing up for greener power or purhchasing green electricity ceritificates or carbon offsets like Terrapass. The typical EV does not charge from the typical grid because enough EV owners are getting green power or carbon offsets to make EV power, as a whole, cleaner than the grid. Many analysis of EVs overlook this. And it can cost fairly little - $100 to $200/ year for carbon offsets to take EVs to zero carbon. Should be offered as an option when you purchase the car!!

Wikipedia: Renewable Energy Certificates (United States)
EPA: What is a Renewable Energy Certificate (REC)
Department Of Energy (DOE): Renewable Energy Certificates (RECs) providers

Terrapass carbon offsets are $0.00595/lb.
Using 45 lbs Carbon/100 LEAFmiles natural gas marginal from above, and using 15,000 miles/year for average vehicle mileage yields 6,750 lbs Carbon/year. Using the Terrapass $0.00595/lb carbon offset cost:

It costs $40.16/year to offset the Carbon from a LEAF! (PG&E electricity)

Carbon isn't the whole story, but if your worried about the Carbon from using grid electricity to charge your LEAF, just purchase some carbon offsets, in the whole picture of vehicle ownership - they're dirt cheap! And depending on how you account for it they get you very close to True Zero Emissions Vehicle.

Yodrak · May 31, 2011

Marginal numbers apply at all times of the day.

You are correct that nuclear generation is fixed, independent of demand. It is what it is, whatever is available. Likewise most renewables, particularly wind and solar, but for a different reason. The output is dependent on the weather conditions, independent of demand. It is what it is. Large hydro also does not follow demand. Hydro is dispatched on the basis of several factors that vary slowly over long periods of time.

That leaves the fossil fuel plants to follow the load demand second to second, minute to minute, hour to hour. In California that's primarily natural gas. Most of the time that gas is fueling highly efficient combined cycle generation and somewhat less efficient steam generation. At peak times, very few hours per year, it's also fueling highly inefficient combustion turbines (big jet engines).

planet4ever said:
Wouldn't the marginal numbers apply only if you were charging your LEAF in the afternoon? I do virtually all of my charging during off-peak hours. I seem to remember reading that natural gas generation can be dialed up or down fairly easily, while nuclear cannot. It would seem like large hydro would also be easy to moderate, though perhaps not. In any event, I would guess that off-peak generation might be more heavily weighted toward nuclear, hence I would expect lower numbers off-peak than the PG&E average.

Ray

Yodrak · May 31, 2011

Thing is, buying offsets or not buying offsets does not change where the electricity comes from, it only changes who is paying how much for it. A wind turbine somewhere does not increase output when you plug in your Leaf, and decrease output when your Leaf finishes charging, because you bought an offset. All those wind turbines out there keep right on generating whatever the wind passing by will allow them to generate. The flow of electrons from the various generators does not change one iota, the flow of dollars changes.

As EricH and I have explained, when a Californian plugs in or unplugs their Leaf it's the gas-fired generators that adjust to accomodate the change in electric demand.

You buying offsets just means that you get to pay a little bit more for your electricity and the rest of us get to pay a little bit less for ours. Thank you!

ElectricVehicle said:
if your worried about the Carbon from using grid electricity to charge your LEAF, just purchase some carbon offsets, in the whole picture of vehicle ownership - they're dirt cheap! And depending on how you account for it they get you very close to True Zero Emissions Vehicle.

davewill · May 31, 2011

Yodrak said:
Thing is, buying offsets or not buying offsets does not change where the electricity comes from, it only changes who is paying how much for it. ... You buying offsets just means that you get to pay a little bit more for your electricity and the rest of us get to pay a little bit less for ours. Thank you!

Where did you get THAT idea? The money paid for offsets doesn't go to subsidize dirty power! It certainly doesn't subsidize YOUR bill. It goes to activities that lower greenhouse gases. Typically reforestation, or the building of NEW renewable energy sources. What they are in reality is charitable contributions.

DaveEV · May 31, 2011

planet4ever said:
Wouldn't the marginal numbers apply only if you were charging your LEAF in the afternoon? I do virtually all of my charging during off-peak hours. I seem to remember reading that natural gas generation can be dialed up or down fairly easily, while nuclear cannot.

Yodrak said:
That leaves the fossil fuel plants to follow the load demand second to second, minute to minute, hour to hour. In California that's primarily natural gas. Most of the time that gas is fueling highly efficient combined cycle generation and somewhat less efficient steam generation. At peak times, very few hours per year, it's also fueling highly inefficient combustion turbines (big jet engines).

Keep in mind that there's different kinds of gas power plants.

There's combined cycle gas plants which can now reach over 60% efficiency, and then they're your peaker plant which might only be 30% efficient.

Historically the high efficiency combined cycle gas plants could not ramp up or down very quickly - any quick rise or drop in power requirements would have to be satisfied by peaker type plants which may only be 20-30% efficient while doing so. So what this really means is that these peakers only really would be called into service due to your charging when you first start or stop - the rest of the time it's all steady state - best case scenario. Ideally everyone would gradually start/stop charging at the same time every night during times of lowest grid-load - that would give the utilities plenty of time to adjust power output to match demand.

Newer combined cycle plants are designed to better handle these types of loads efficiently, and increasingly in the future we will see battery based grid regulation products - so no "burning" of fuel will need to be done. Earlier this year a 8MW flywheeel based grid storage system went online. Hopefully down the road very very of these inefficient gas peaker plants will be needed to run and more of these battery or flywheel based grid regulation products will make it to market - meaning the grid will be cleaner, more efficient - and hopefully also cheaper.

Good article which covers these issues: http://www.technologyreview.com/printer_friendly_article.aspx?id=17285
Disclaimer: it is fairly biased towards Beacon Energy's flywheel grid storage product.

planet4ever · May 31, 2011

Yodrak said:
Marginal numbers apply at all times of the day.

planet4ever said:

Wouldn't the marginal numbers apply only if you were charging your LEAF in the afternoon? I do virtually all of my charging during off-peak hours.

Click to expand...

We seem to be talking about two kinds of marginal numbers. Certainly my marginal tier rate applies at all times of the day. But this is what I was replying to:

JeffN said:
Some say that marginal rather than average generation fuel source is a better model for how the charging of EVs will change utility emissions.

My contention is that neither the marginal utility emission rate (which applies at peak generation time) nor the average fuel source emission is a good model for the effect that EV charging will have on emissions. I believe the effect will be considerably lower than either of those.

Ray

Yodrak · May 31, 2011

Where did I get what idea? That buying offsets does not change the source of the electricity that one is buying? I stand by tha 100%

That the money paid for offsets subsidizes "dirty power"? OK, I was over the top on that - it doesn't subsidize dirty power directly, or fully. Agreed, in retrospect, that those consumers who buy offsets don't likely save money for those consumers who do not buy offsets. Offering offset purchase programs enables the utilities who offer them the trouble of having to spend their own money for activities that lower greenhouse gasses so as to appear 'green'. To the extent that state utility commissions would have allowed such avoided expenditures to be put in rates, it's the stockholders who benefit from the purchase of offsets not other consumers.

davewill said:
Yodrak said:

Thing is, buying offsets or not buying offsets does not change where the electricity comes from, it only changes who is paying how much for it. ... You buying offsets just means that you get to pay a little bit more for your electricity and the rest of us get to pay a little bit less for ours. Thank you!

Click to expand...

Where did you get THAT idea? The money paid for offsets doesn't go to subsidize dirty power! It certainly doesn't subsidize YOUR bill. It goes to activities that lower greenhouse gases. Typically reforestation, or the building of NEW renewable energy sources. What they are in reality is charitable contributions.

California 2009 Power Mix

Help Support My Nissan Leaf Forum:

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Similar threads

Join the conversation!

Join today and get all the highlights of this community direct to your inbox. It's FREE!