Featured The impact on utility rates in CA of EV charging

This assumption sounds a bit too simple, possibly inflating the claimed benefit:

Undoubtedly, some EV customers are on such a tiered rate plan. But I've understood that numerous are on different plans: EV metering separate from the home itself, often at a fixed lower rate; time of use (TOU) metering; and home solar PV producers on net-metering or other plans, many installing enough PV capacity to produce all their electric energy.

It seems that it would be important to either look at how EV owners are apportioned to these types of plans, or show some reason to believe that the tiered-rate assumption is fairly close to reality, that an insignificant number are on the other plans.

 

It makes sense that if EV owners are typically charging at night, when the grid is underutilized, that this would be providing extra income to the utilities at little additional expense.
It seems like this would happen in any climate since electric use at night is always lower, on average.
In addition, nudges, via lower TOU pricing can incentivize night time charging and most customers can easily do this.

Mike

 

I understand what you are saying about off-peak hours.

In our locale the rates are constant and never vary regardless of the time or day.

We have a PHEV and it is always plugged in regardless of the day or time - it is nice not to worry about the time or day.

It is also nice not to buy gas but easy to forget that our transportation cost is now baked into our electric cost. We did notice a big boost in our electric bill when bought the PHEV, but for now is still less than gas.

I understand that with gas rates falling and even using off peak charging it is cheaper in much of the country to drive on gas rather than electric.

I would not be a proponent of artificially raising the price of gas to artificially make EV's more attractive. Then a few years later reveal the real cost of electric powered transportation to the shock of the consumer.

It would be nice if Battery/EV technology was such that it beat the cost of gas no matter where you where located. People would then flock to electric transportation as it made the most economic sense. As an added bonus it might give a measure of energy independence to the US.

Maybe that Technology breakthrough will happen in the next few years.

 

why do some areas not offer tou? are there different generating systems that don't waste unused energy?

 

I am guessing that in some regions it just isn’t a big deal. Minnesota has started moving that direction as it became more beneficial to have EVs charging overnight.

The average cost of electricity beats the average cost of gas in the USA.
While some in the country do have higher direct costs for electricity vs gas, most of the country does not.
When you include externalized costs (pollution causing medical issues, lost work, climate change, etc) electricity is cheaper than gas, everywhere.

 

in the heat of summer, when a/c is at its height, we are asked to reduce usage in the daytime, to prevent brown outs.
so most of the time, there is plenty of supply. maybe that will change as more ev's are charging, and they will offer some night time rates

 

Others have long argued that U.S. gas prices are artificially low.

Lack of meters capable of TOU metering is a major impediment. Now that my local area is finally converted over to "smart meters" capable of it, a voluntary TOU program will start in 2024.

Hydroelectric plants don't waste it, they just throttle back the water flow, saving the water in the reservoir until it is needed.

At least, until environmentalists started fussing that sharp diurnal river flow variations in some places were harming fish nests and causing serious river bank erosion. It became more prickly when we learned that a bunch of Washington and Oregon salmon egg nests were destroyed to prevent California blackouts during the Enron fraud a couple decades ago. Regulations now impose minimum flow requirements, and maximum slew rate limits, so sometimes water must be spilled outside the generators in order to meet those requirements. Shifting more load to the overnight lulls would help reduce the diurnal swings, and help producers meet the water flow requirements without dumping water over spillways.

 

we have mostly gas gnerators. why can't they be slowed down at night, not multi speed?

 

The study, https://www.nrdc.org/sites/default/files/media-uploads/evs_are_driving_rates_down_dec_2022_update_0.pdf, itself gave a bit more detail, though it isn't the clearest written.

"We developed two scenarios to analyze the revenues and costs from EVs: one in which we assumed EVs took service on tiered rates and charged without respect to system costs, and the other in which we assumed 75 percent of customers took service on a time-of-use (TOU) rate and charged primarily off peak."

The $1.7 bil figure was on the assumption of mid tier rates from 2012 to 2021. It was $1.4 bil under the TOU scenario. The short paper spent more time talking about how EV homes with TOU shifted towards off peak usage(I think one figure mislabled on peak). Separate EV metering got a paragraph about its off peak usage. There was an undefined EV programs among the utilities' costs. The study didn't look directly at revenue from scenarios using cheaper EV charging plans, but the costs of running such seem to be subtracted for those 'profit' figures.

A PV home seems beyond the scope of this little study. EV's bring in enough revenue over the utility's cost that profit caps lower rates for all customers. How does a PV home factor into that profit cap calculation? One that is net zero probably adds little revenue to the utility, with or without an EV.

A factiod in the paper; EV homes in Ca see an average monthly electric increase of 260kWh.

The meters are the big hinderance.

If turbines, they are the best at varying output. Shutting them down completely may not be an issue.

I don't think much electricity made at night is wasted. That might actually be true for steam plants(mostly all coal or nuclear), as letting the boilers go cold can cause break downs. Making it cheaper cost wise to leave steam production going at a minimum 24hrs a day. The issue for power plants at night that the low usage means they are likely running inefficiently. Those steam plants could being making less electricity than their minimum fuel burn could make.

The energy waste is in the fuel used to make the electricity. If the utility charges more for less efficient use of fuel, even less will be used at night. Entice customers to use more electricity with lower off peak rates, and the increased usage can put their plants at a more fuel load. efficient

 

Standard (*) AC generators are inherently fixed speed. Trying to use multi-speed on the utility grid would be like forcing a gear shift on a manual transmission without a clutch, and with enough force to rip the transmission apart.

AC generator output power is changed by changing the torque on the input shaft. RPM stays constant whether the turbine or engine is idling or running at full power or anywhere in between.

(*) Stand-alone inverter generators, such as those portable Hondas and similar, are a different thing.

 

Just like regenerative braking, putting more electric load on a rotating generator causes it to need more water or steam flow to maintain the RPM setpoint.

Mike

 

Prius regenerative braking involves highly variable RPM, and is mediated by lots of electronic semiconductor junctions in the motor/generators controllers between it and the battery, so is not analogous to utility grid generators.

When an AC generator is synced and connected to the utility grid, it is locked to its standard fixed RPM by the grid itself, regardless (almost) of how much water or steam is pushed into the driving turbine. There are no electronics in between, just copper wire and magnetic transformers. Whether the water or steam turbine is driven hard, or idling lightly, or even shut off completely, the whole system stays at constant RPM. In the later case with no water or steam into the driving turbine, the AC generator becomes a motor, driven by the 'infinite bus' of the utility grid, and drags the unpowered turbine along for the ride, still at full RPM.

The later mode is actually a valid operating mode on many machines. It effectively becomes a giant capacitor or inductor (depending on the excitation current, a controllable parameter) to provide needed reactive power (sometimes called 'imaginary' power, but a real-world thing). With hydro, it is also (or very close to) 'spinning reserve', ready to supply power on a moment's notice in case other generators trip out. When I visited Grand Coulee long long ago, one of the machines on the tour was in this operating mode.

If you put enough torque on an AC generator's shaft, you can cause it to "break sync'. This is not pretty, one plans for circuit breakers to trip out first. If I remember my machines class correctly, on typical low speed generators such as hydroelectric machines, this may be not much larger than full power torque, depending on how the excitation is set up and the electrical properties (impedance) of the transmission lines to the rest of the grid. It will be a very noisy and high vibration event. On faster machines, such as steam turbine systems running at 3600 RPM, it will take far more torque than that. Design for the circuit breakers to trip before mechanical breakage occurs.

 

One would think a net zero system would represent a windfall to the utility especially as more and more new communities / developments are created. SoCal requires these new developments to have PV as part of new community's creation. For example wouldn't that mean old transformers don't have to be upgraded? ie money not spent represents profit on the ledger?
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Its important to remember that sun and wind don't shine and blow evenly or even predictably across a state unless it is tiny or doesn't have much capacity. To utilize this better states like texas have put in more infrastructure to move the renewables from where they are best created to where they are used. This means more money, not less, on infrastructure. In New Zealand south island that has plenty of power to be all renewable, the infrastructure makes electricity expensive because low population density and earthquakes. In a state like California the infrastructure cost/kwh is low compared to the cost of not doing it for the population centers. Sparsely populated northern california
means that things should be done for reliability but costs are high. That includes building more ccgt natural gas plants to account for shortfalls of hydro that are predicted to happen more often in the future. It is really a scandal that should involve jail time for the poor maintenance and infrastuture failures that have caused fires and loss of life.

Newer ocgt and ccgt generators can cycle quickly within a power range. For ccgt full power is not achieved until the steam turbine is functioning well. For a typical 2000 or later power plant this is around 2.5 hours for cold start to full power. Newer plants have options to pre heat (use natural gas less efficiently to start faster, and have extra equipment) and may be from cold start to full power in 30 minutes or less. For the GE range of generators they can easily toggle from 40%-100%, they lose the steam turbine bellow this range but can still operate at 20% and be ready to quickly ramp. Each turbine can be started in about 20 minutes. Build 3 x 500 MW ccgt plants and infrastructure to operate together, and they can ramp from 200MW-1500MW quite efficiently, but probably should at least keep 100 MW spinning instead of shutting down completely just in case.

Steam generating plants are older and can not ramp power up and down as easily. Utilities like to keep these around because they are paid for.

 

Being good for the utility doesn't automatically equate to increased profits to the point that they have to give rate payers a discount.

Comes down to the net metering accounting. If the utility ends up paying the PV owner, it is good for the owner, but everybody else is paying the base rates.

The lower electric bills from EVs only happen in jurisdictions in which there is profit caps on the utility.

 

It doesn't make sense that california, which generates only a portion of its own electricity can offer power to electric cars on the cheap. Major reservoirs - which bring power into California (like Lake Mead) are nearing the point of being Deadpools as the water levels reach record lows. The hydroelectric generators will no longer spin at that point. What's missing from that scenario .... where existing customers are told not to hose down their driveways or water their lawns, all the while less essential water use (ski lifts, new communities constructed, golf courses in the desert etc) continues.
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EV owners aren't getting energy on the cheap in California. The increased electric usage from them means the power companies are more likely to hit the profit caps, and then have to reimburse all their customers in some way. The EVs and shifting more electric usage to off peak does lower the utility's costs on plants that would otherwise be turned down or idled during those times. Which further increases the odds of hitting the caps.

 

I believe the cost of a variable cost of a ccgt power plant is about $0.02/kwh. California imported about 30% of its electricity last year, much of this natural gas, and that amount will go up if they do not build in state. Transmission losses will be lower if california builds some of the plants in state but there are costs associated, and the utilities own some old ineffiencient natural gas thermal plants that they would prefer to run instead of reclaim the land, and any good regulation would choose the closer more efficient plant first - but current PUC won't fix the problem, and the state isn't going to allow new utilities (things other than SCE, PG&E, SDE) to make enough profit with enough certainty to invest. CCGT plants other than being more efficient and able to change power to the grid needs more quickly also use less water than natural gas thermal plants.

Say California built enough ccgt plants and associated grid infrastructure to replace half of the imported energy (15% of today's usage), it likely be able to be run profitably at $0.08/kwh to retail consumers, and I doubt California will be able to build enough in state renewables to make up for the loss of the nuke plant and the drought very quickly. If the PUC continues to favor imports and old plants though then utilization may be low and they will need around $0.20/kwh.

 

austingreen

I have a question for you.

Our local utility has a big push on to get all customers to upgrade to a "smart meter" .

Are there any concerns to letting them upgrade our convention electric meter?

Is this a precursor to time-of-day metering?