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ORNL Study Explores PHEVs’ Impact on Power Generation Requirements

Ornlphev
Sum for all 13 regions of projected 2030 generating capacity (top left), base generation (top right), and new generation dispatched (bottom) to meet demand for each PHEV recharging scenario. Click to enlarge.

A recent Oak Ridge National Laboratory (ORNL) study examines how an expected increase in ownership of plug-in hybrid electric cars and trucks could affect regional power generation requirements depending on what time of day or night the vehicles are charged. The researchers concluded that supporting a 25% market share of light-duty (cars and SUVs) PHEVs in 2030 could require either major new power generation resources or no new resources at all, depending on when people recharge.

The ORNL study also factors in the impact of the different options for connecting vehicles to the grid. As Dr. Mark Duvall at EPRI has outlined, at 120 volts AC, a 15 amp circuit would be about a 1.4 kW load, while a 20 amp circuit would be about 2 kW. Using a 208/240 volt and 30 amp circuit instead, the load could be as much as 6 kW.

In the worst-case scenario—if all PHEV owners charged their vehicles at 5 p.m., at 6 kW of power—up to 160 large power plants would be needed nationwide to supply the extra electricity, and the demand would reduce the reserve power margins for a particular region’s system.

The best-case scenario occurs when vehicles are plugged in after 10 p.m., when the electric load on the system is at a minimum and the wholesale price for energy is least expensive. Depending on the power demand per household, charging vehicles after 10 p.m. would require, at lower demand levels, no additional power generation or, in higher-demand projections, just eight additional power plants nationwide.

In aggregate, the model predicts an increase in demand, generation, electricity prices, and emissions from the utilities created by the introduction of PHEVs. It also suggests that by 2030 almost all regions (10 out of 13) will need to add capacity to provide for charging PHEVs, mostly in the scenario where PHEVs are charged at 6 kW in the evenings. In all likelihood, to avoid these problems the utilities in the regions would expand their capacity, increase their imports, or establish demand response programs beyond the level that NEMS had calculated, but these factors were not modeled in the scenarios.

—“Potential Impacts of Plug-in Hybrid Electric Vehicles on Regional Power Generation”

Some assessments of the impact of electric vehicles assume owners will charge them only at night, said Stan Hadley of ORNL’s Cooling, Heating and Power Technologies Program.

That assumption doesn’t necessarily take into account human nature. Consumers’ inclination will be to plug in when convenient, rather than when utilities would prefer. Utilities will need to create incentives to encourage people to wait. There are also technologies such as smart chargers that know the price of power, the demands on the system and the time when the car will be needed next to optimize charging for both the owner and the utility that can help too.

—Stan Hadley

The paper also compares the fuel use, emissions, and cost of using a PHEV versus a hybrid electric vehicle (HEV) for each region, with both vehicles going 20 miles per day and the efficient HEV getting 40 miles per gallon, in the different scenarios.

In both of the 2020 scenarios and the night scenario in 2030, CO2 emissions are higher with PHEVs than with efficient HEVs. Coal and oil generation is sufficient to raise CO2 emissions higher than if the vehicles had used gasoline. However, in the 2030 2 kW evening scenario, CO2 emissions are lower, because higher-efficiency combined cycle plants and gas-fired turbines with relatively low emissions are used to meet the added demand.

Even though NOx emissions at first calculation are much higher for much of the country, these will be offset by reductions elsewhere. Even though new power plants are very clean, the plants that are on the margin and are run because of the extra demand may actually be older plants with higher emissions. SO2 emissions are likewise positive, but will be offset by reductions elsewhere in the electric system because of the legal caps on total emissions.

Costs are much lower with the PHEVs, from 22% to 42% of the gasoline cost, depending on the scenario. Electricity is likely to be much cheaper than gasoline, though this does not take into account the added initial cost of the plug-in capability for the vehicle.

—“Potential Impacts of Plug-in Hybrid Electric Vehicles on Regional Power Generation”

The researchers analyzed the potential impacts of PHEVs on electricity demand, supply, generation structure, prices, and associated emission levels in 2020 and 2030 in the 13 regions specified by the North American Electric Reliability Corporation (NERC) and the US Department of Energy’s (DOE’s) Energy Information Administration (EIA), and on which the data and analysis in EIA’s Annual Energy Outlook 2007 are based.

The estimates of power plant supplies and regional hourly electricity demand come from publicly available sources from EIA and the Federal Energy Regulatory Commission. Electricity requirements for PHEVs are based on analysis from the Electric Power Research Institute, with an optimistic projection of 25% market penetration established by 2020 and continuing at this percentage level through 2030, involving a mixture of sedans and sport utility vehicles. Even though the market share remains the same, the increase in the fleet size results in larger annual sales of PHEVs post-2020.

The calculations were done using the Oak Ridge Competitive Electricity Dispatch (ORCED) model, a model developed over the past 12 years to evaluate a wide variety of critical electricity sector issues. Seven scenarios were run for each region for 2020 and 2030, for a total of 182 scenarios. In addition to a base scenario of no PHEVs, the authors modeled scenarios assuming that vehicles were either plugged in starting at 5:00 p.m. (evening) or at 10:00 p.m.(night) and left until fully charged. Three charging rates were examined: 120V/15A (1.4 kW), 120V/20A (2 kW), and 220V/30A (6 kW).

The analysis, the authors note, uses simplifications in modeling electric sector supply and demand. The model applies rigid recharging schedules to all vehicles in each scenario, it does not adjust electricity supply to meet increased demand, its inventory of supply is based on results from a different model (the National Energy Modeling System, or NEMS) that simulates supply and demand somewhat differently, it does not model the transmission system, and it does not reflect all the complexities of air emissions regulations.

However, it does offer insights into the issues involved with PHEVs and the electric grid. PHEV penetration of the vehicle market will potentially create a substantial change on the electric grid. By evaluating these issues early, DOE will be able to help utilities, manufacturers, and regulators understand the issues involved, suggest ideas that will better optimize the combined system, and help avoid negative consequences.

Resources

Comments

DS

"In the worst-case scenario—if all PHEV owners charged...."
This scenario is as meaningful as the one I used to heard in high-school about every Chinese getting on a chair and jumping down at once to alter the earth's axis.

mahonj

If you are going to the expense of building a PHEV, you will surely add (at the very least) a timer to make sure you charge at night.

Better still would be a "smart" charger which can charge during the day when there is excess wind / power in general, and can time the charging optimally at night.

Compared to getting the battery right, this is surely trivial.

You could promote this by giving tax incentives for fitting such meters and timers etc.

Another comment is the notion of "efficient" HEVs getting 40MPG - by 2020 ???

Surely we have these now - there are loads of cars in Europe and Japan that get better than this - either small, diesel or hybrid.

Oil at $110/barrel might bring these to the US faster than anything else.

Jim

I don't get all this hand-wringing about the power grid with respect to PHEVs. Especially since there are none on the road today. It's almost kind of spooky, like building a few power plants would be worse than having the country beholden to foreign oil interests. Like Mahonj has said, how hard is it to add a timer to a charging unit?

A simple strategy would be to require additional renewable energy sources developed for each PHEV purchased in that state. Then the intermittent nature of renewable electricity could play well with the PHEVs which could accommodate intermittent charging. Problem solved.......

K

These Gridload/PHEV studies seem to be coming from every direction. Are all grants expiring at the same time?

This topic was discussed in great detail about two weeks ago in regard to V2G, Smartgrid, etc. I can't get to this one now but look forward to comments from others.

sjc

There is no problem now with the few Prius upgrades, but are the number of PHEVs sold going to be monitored once they get to the car lots? If not, then you may have LOTS of them sold in one area and no preparation for the local grid. It may not be a problem, but then again it could. I would rather consider all the relevant factors BEFORE the fact.

Usually, the home is characterized as all electric, or electric and gas heat and so on. This is for resource planning. Now you have a vehicle that could consume on a continuous basis for many hours as much as an electric clothes dryer. I would want to know if 1000 of these were sold in a neighborhood if I were the power company.

Arnold

There is no 'law of ' that states phev's must be base load.
Indeed if economy is enshrined in concept, then it is apparent that solar , wind and other non base load wastes can be mopped up by one form or another of PEV concepts.
This has as much merit as any other pollution reduction or remediation.
Engineers and techs really should get with the program ie Edward DeBono's lateral thinking philosophies and have less time for contemplating what cant be done as a stating point.
All artists start with a clean page, Its called artistic, poetic license.
I propose an "Engineers licence be added to these elite and an assumption that they do know what they are talking about as well.
In how many shops is the motto the Impossible we can do straighht away, Miracles may take a little longer.

Neil

When I first got my electric motorcycle I replaced all of my light bulbs with CFLs. Any change in my electrical bill was imperceptible.

Robert Marston

I agree with others who have stated that a recharge timer would be a very easy way to solve any loading problems. One other point of the study I find to be a bit ridiculous is that it assumes a massive build-up of coal fired power generation through 2030. It would be very unwise to become so reliant on coal in the next 20 years. Coal supplies will peak worldwide and we'll be in the same situation we're in now with oil.

Is there some kind of disease these people get that destroys their vision? It really is uncanny the nonsense they put out.

aym

How about this. It's a smartgrid, we have a minimal charge of the PHEV/EV. If you want to charge it more between 9am-5pm like a putz then you get a warniing - you are going to be charged 10x-20x the cost of the power. There. That should stop the low blood flow above the neck crowd and give utilities extra money to upgrade what they need.

Didn't they already have something about 80% of the energy could be suppllied if charged overnight study from the DOE? Put in increasingly heavy penalties for the additional burden or have em put in solar cells or some such or both. Sorry bout the reply. Not my usual eloquent self today.

Rafael Seidl

Consumers are creatures of habit, but as CNG owners with Phill stations are demonstrating today, new habits can be formed easily enough. If nighttime electricity is cheap, people will happily trickle-charge the EV they use for commuting and running local errands. For longer trips, they'll either fall back on the on-board genset (cp. Volt) or else, use a conventional car. Most families have more than one vehicle, not all will be pure EVs.

@ Robert Marston -

you grossly underestimate the amount of coal available. We'll have a runaway greenhouse effect before we run out of that stuff.

Jabroni

Ridiculous. Where do these people get such nonsense? Not one PHEV is being manufactured today and yet these "brilliant minds" can extrapolate non existent data out to the year 2030 and tell us we need an additional 160 power plants? Using the electricity in the late evening/early morning to charge the vehicle actually HELPS our grid. Does any writer ever mention this? I for one, do not want a HEV, I will only settle for the hybrid with a plug!

mithbustr

Arnold,

though I cannot understand what you allude to, the style with which you do it is... worthy. Clearly the feds are scrapping to justify their bloated budgets. Even a "dumb" timer would limit charge to late night low cost rates - that's one of the rather obvious benefits of BEVs. A minimally "smart" charger would look for the lowest cost rate and lock it in for the night.

How 'bout moving some of this excess engineering talent to pony up the truth about global warming - instead of these barely concealed sand bagging efforts to study grid evolution?

macroshaft

Once again, a research team neglects to take V2G into consideration.

If charged to 100% on the off-peak rates - and if the trip to work & back only takes fx 40% - what's to stop the vehicle owner from selling some of the 60% to the utility, at peak rates? - Smart meters - ofcourse!

Might even go some way, to pay for the battery.

DS

"Ridiculous. Where do these people get such nonsense?"
Lets see. Oak Ridge is located in the Appalachian Mountains. I wonder if there's any coal mining there?

Bill Young

For those who think this study is silly, reflect on the fact that PHEV and EV vehicles may hit the mass consumer market in 2 to 3 years. (The Tesla is now in limited production; White star is supposedly 2 years behind it. The Volt is supposed to enter the market in 2010). The market response to these vehicles is largely unknown but if gasoline is $5 or $6 dollars/gallon, it could be profound.

The lead time from planning to power on the grid for new power is on the order of 10 years (longer for nuclear). The grid already has insufficient reserves in parts of the country.

Of course it is not realistic to think that all grid powered vehicles will be plugged in at 5pm. This is what is called a worst case bounding scenario.

It is studies like these that define the need and value for timed or web initated chargers as well as additional power generation.

Bill

robin

What am I missing? This seems like a simple solution.

Just retrofit the house's meter to be a bidirectional programmable service.

Have the use a pricing scheme that reflects time of use.
Give owners the ability to easily program the interface and allow the power company the ability to monitor service in realtime.
You might even make it so owners could allow their car sitting at home to be used by the power company in a time of need.

I'll bet you'd have people charging at off peak times and allowing power companies to draw some from their batts when they need.

sjc

All that can be done, but may not be done now. My power company could have implemented power line networking and read every electric meter by computer control from a central office instead of sending out someone in a vehicle to read the meter, but they have not done that and still don't do that. Utilities are a regulated monopoly. That was part of the deregulation con...make them more competitive. All it did was allow Enron and others to game the system and black out the state.

solarnano

Time to purge all of the agencies of old fossils with their fossil fuel degrees. and replace them with young greens with renewable energy degrees. By doing this there will be no need for imported fuels and certainly no need for coal. In the Old Fossil Club it is tantamount to treason to wear a green tie, let alone utter the word. These guys don't even eat salad. There are so many ways to power everything with renewable energy, they can't even be counted. Six thousand square miles (6% of the Sonoran Desert) can replace all fossil fuels by using algae, alone, to make biofuels to fuel electric generation and power everything we need in the US by 2030. No infernal combustion engines needed, and no carbon emissions. The carbon created from the generation of electricity, is pumped right back into the closed loop system to grow more algae. All those old fossils are sticking it out, waiting for their retirement checks. I think it would be way cheaper, in the short and long run, to buy their early retirement and, let young greens in to guide us into an all electric, clean, no fossil fuel, green ties, lots of greens on the table, future.

solarnano

Time to purge all of the agencies of old fossils with their fossil fuel degrees. and replace them with young greens with renewable energy degrees. By doing this there will be no need for imported fuels and certainly no need for coal. In the Old Fossil Club it is tantamount to treason to wear a green tie, let alone utter the word. These guys don't even eat salad. There are so many ways to power everything with renewable energy, they can't even be counted. Six thousand square miles (6% of the Sonoran Desert) can replace all fossil fuels by using algae, alone, to make biofuels to fuel electric generation and power everything we need in the US by 2030. No infernal combustion engines needed, and no carbon emissions. The carbon created from the generation of electricity, is pumped right back into the closed loop system to grow more algae. All those old fossils are sticking it out, waiting for their retirement checks. I think it would be way cheaper, in the short and long run, to buy their early retirement and, let young greens in to guide us into an all electric, clean, no fossil fuel, green ties, lots of greens on the table, future.

solarnano

Time to purge all of the agencies of old fossils with their fossil fuel degrees. and replace them with young greens with renewable energy degrees. By doing this there will be no need for imported fuels and certainly no need for coal. In the Old Fossil Club it is tantamount to treason to wear a green tie, let alone utter the word. These guys don't even eat salad. There are so many ways to power everything with renewable energy, they can't even be counted. Six thousand square miles (6% of the Sonoran Desert) can replace all fossil fuels by using algae, alone, to make biofuels to fuel electric generation and power everything we need in the US by 2030. No infernal combustion engines needed, and no carbon emissions. The carbon created from the generation of electricity, is pumped right back into the closed loop system to grow more algae. All those old fossils are sticking it out, waiting for their retirement checks. I think it would be way cheaper, in the short and long run, to buy their early retirement and, let young greens in to guide us into an all electric, clean, no fossil fuel, green ties, lots of greens on the table, future.

Emphyrio

ACEEE have shown in their studies that simple electricity saving measures with reasonable payback today can save 25% of current US electricity consumption.

The miles driven by US drivers today could ALL be convereted to pure BEV miles (if the vehicles had the range) and be driven purely on that saved electricity - in fact, with the electricity that could be economically saved today, you could drive US LDVs 33% more miles than they do today.

So Americans - you could save some electricity and power ALL THE MILES YOU DRIVE AND MORE WITH THAT SAVED ELECTRICITY. No more power plants and no more oil at all.

Never mind the better efficiency for power plants of cars providing a charging load at night and the need anyway to have full scale clean renewable electricity built.

How long will it take to get 25% ie 4 million PHEVs a year on the market? Hurry up.

John Taylor

There are complicated high tech expensive solutions, and also a cheap efficient foolproof one.

Line voltage drops with increasing load, and increases with increased power generation. A variable "peak-meter" that charges more in times of grid stress, and an available energy management system that shuts down loads in times of higher prices will go a long way to regulating a far more consistent power load.

Also, encouraging home generating/storage systems will provide a fail safe network.

The "studies" by high paid engineers often fail to see the obvious.

Ben

This report does not assume smart grids and V2G comes around with the PHEV and EVs: its not hard to have a EV that talks to the power networks and finds the best times to charge, how fast to charge and even to dump power back into the grid. The was a previous article way back that showed ~80% of all light vehicles could go PHEV and with a smartgird would require no new power plants. What needed now is not talk but standardization of smart grid technology and implementation of the system very soon.

Harvey D

It seems that too many exagerate the difficulties of producing enough electric energy to charge 200 million PHEVs and BEVs.

There are about 10 efficient methods to produce electricity. It is a mature technology and as such it is not much of a challenge. Power Cos will galdly produce more when required. Charging PHEV-BEV at night is an ideal way to level the power consumption and maximize the power plants efficiency. However, authorities must regulate GHG produce by existing and future power generating plants. A ceiling must be applied on GHG per KWh produced.

The net gain in efficiency between the current ICE gas guzzlers and future PHEV-BEV will reduce energy consumption and could reduce GHG emissions significantly.

PL

I would just as soon recharge my future electric car using PV panels during the day. The car is parked in the sunshine during daylight while at work. A win-win would be to install PVs as a sort of carport roof, and park in the shade of them, thus trickle charging AND keeping the car out of the hot sun.

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