Electric cars and CO2 emissions

[Lake Girl]

Recent article from CBC news ... green effect of electric cars depends on where/how your electricity is produced.
http://www.cbc.ca/news/canada/nova-...they-really-more-polluting-than-gas-1.3012929

 

[Dune]

This is the latest propaganda, the second article from CBS in two weeks to spout this nonsense.
The "study" is not a study at all but rather an opinion piece.
In my attempts to contact the author (unsuccessful) I learned that the University of Toronto is unaware of his existence as a Professor at their school.

The paper itself provides no mathematics whatsoever to support this absurd claim.

Furthermore, I question (assuming the author is who he says he is) whether a civil engineer is qualified to perform this study in the first place. To me it falls under the realm of mechanical engineering not civil.

Those preliminaries aside I will address the concept since there are no statistics presented by the author to check (someone else may have better luck finding a more complete paper than I did)

Indisputable facts;
1. The average ICE (internal combustion engine) is just 20% efficient meaning that 20% of the energy released by the burning gasoline is converted to motion, the rest wasted as heat.

2. The average diesel ICE is just 30% efficient. (a whopping improvement yet still very wasteful)

3. The average electric motor over 100 HP is over 92% efficient.

4. The average coal fired electric power plant is 40% efficient with average transmission line losses of 7%.

5. In the US in just the last 15 years alone our use of coal for electricity generation has dropped from 50% to 39% and continues to drop as older dirtier coal plants are
shut down and renewables come on line.

6. The study is about Canada, a country far less suited to electric cars than the US.

From the above one can readily conclude that an electric car is uses significantly less energy than a gasoline ICE car and somewhat less energy than a diesel ICE car.

Furthermore, were one to use electricity from a clean source such as nuclear, solar, wind, hydro or tidal current the reduction in carbon emissions is vast.

Also not mentioned yet mention worthy is the fact that an electric car helps reduce our trade deficit and increases national security by reducing reliance upon imported oil.

Finally all electric cars charged by the grid make the grid smarter by acting as capacitors and some (such as the very popular Prius) also can act as distributed power

generators, further enhancing the grid.

The final nail in the coffin of this ridiculous concept is that by charging at night (during the period of least demand). grid operators can more readily balance plant output enabling some generators to generate at night rather than the current wasteful process of idling at night (burning less but still some fuel to keep steam temp and pressure up while providing zero output.

 

[Lake Girl]

Didn't mean to cause such angst. Not sure of the validity of any claims... just found it interesting. It is from CBC (Canadian Broadcasting Corporation)... not CBS. Here's the one from CBS:
http://www.cbsnews.com/news/think-electric-cars-are-truly-green-not-if-their-power-comes-from-coal/

The UofM prof's info on ethanol is interesting too... Canada has mandated ethanol content.

As to Dr. Kennedy... I would argue that he is a real prof.
(broken link removed to http://www.civil.engineering.utoronto.ca/staff/professors/kennedy.htm)
(broken link removed)
http://www.news.utoronto.ca/going-g...d-do-more-harm-good-it-depends-where-you-live

 

[Ashful]

I question (assuming the author is who he says he is) whether a civil engineer is qualified to perform this study in the first place. To me it falls under the realm of mechanical engineering not civil.

What am I missing? First image in the article is subtitled, "Lucas Swan, a professor of mechanical engineering at Dalhousie University..."

The final nail in the coffin of this ridiculous concept is that by charging at night (during the period of least demand). grid operators can more readily balance plant output...

How's that ridiculous?

Didn't mean to cause such angst.

 

[Lake Girl]

What am I missing? First image in the article is subtitled, "Lucas Swan, a professor of mechanical engineering at Dalhousie University..."

He's driving his electric car in Nova Scotia ... one of the provinces that still has coal generated electricity sources (not sure of percentage of total generation). Dune is referring to the UofT prof, Chris Kennedy, a civil engineer who was an author of the study mentioned in the article.

Just found the article thought provoking in that I never really pondered the source of electricity as I'm in an area surrounded by hydroelectric dams.

 

[Ashful]

Lots of coal power, here. My FIL was plant manager of what was, at that time, the largest coal-fired generation plant in the world. They're still running that plant on coal today, although it's been scaled down and now burns waste coal.

Current usage for that plant is 4,000,000 tons per year, charging quite a few Priuses and Teslas!

 

[EatenByLimestone]

Biggest killer of electric cars here is the price per kwh. Almost 23 cents per kwh makes it a hard pill to swallow.

 

[Dune]

No angst at all Ms. Lake, I have been refuting this argument for almost 20 years. Now it is coming from universities not just fossil fuel shills.
I hope you didn't take my sentiments personally, it certainly wasn't directed at you.
I find it best to get out ahead of these types of things as quickly as possible, which is why I attempted to talk to the Professor.

 

[iamlucky13]

5. In the US in just the last 15 years alone our use of coal for electricity generation has dropped from 50% to 39% and continues to drop as older dirtier coal plants are
shut down and renewables come on line.

Just a nitpick, but the main source picking up that 11 percentage point drop in coal is natural gas, and that's in part because low gas prices are leading coal operators to run plants that are still licensed less. If gas prices go back up, coal production is expected to tick slightly upwards again.

The total of all renewable sources except hydropower in the US is 6.9%:
http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_1_1

Furthermore, I question (assuming the author is who he says he is) whether a civil engineer is qualified to perform this study in the first place. To me it falls under the realm of mechanical engineering not civil.

Environmental engineering is generally more closely tied to civil engineering. Regardless, both disciplines are capable of this type of calculation, especially since there's readily available data now on CO2 intensity of various generation methods, saving them the chemistry most engineers of both disciplines have forgotten since they took it sophomore year.

As for electric cars, I've checked the math myself, although I didn't save the napkin, so from memory I can only offer rough comparisons. It looked like the worst case for models currently on the market is a 100% coal-powered electric car has only a very slight edge in CO2 emissions compared to an average car, and a slight disadvantage compared to a good hybrid. Of course, 100% coal powered isn't a real case, and even switching to natural gas changes the picture significantly. In areas with lots of hydro, wind, or nuclear power, it gets a lot cleaner, fast. And if you're comparing a Tesla to an equivalent ICE car like a Porsche Panamera, rated at 19 mpg, the CO2 reduction is even more significant

 

[woodgeek]

A nice, thorough (free access) peer reviewed paper here: http://www.pnas.org/content/111/52/18490.full.pdf

They separately analyze and compare the air pollution (PM2.5, O3), climate impacts (CO2) and mining costs associated with all alternative fueled light vehicles.

Bottom line: Compared to gasoline in a conventional ICE engine, ethanol in an ICE or an EV running on 'grid average' US power both reduce total CO2 slightly, but have net positive damage to the environment. Both are better re the future climate (since CO2 sticks around for centuries), but worse for kids with asthma (O3) or that guy with the bad ticker (PM2.5) in 2015.

The increases for EVs are almost entirely driven by coal mining and plant emissions. EV do better on both metrics than gasoline on a gas-fired grid, on a nuke grid (presumably, not considered), or with wind water or solar (WWS) powered grids.

RE the batteries: these authors state that earlier researchers had sited all battery material mining emissions at the auto manufacturing plant (with dense population) rather than the actual mining site (in a remote area) and thus significantly over-estimated the effect on human health. Where the pollution is emitted matters.

Some stats:
-- 40% of EV owners have their own PV installed. (for a Hearth example, Begreen and his Volt EV)
-- >60% of US EVs are on the west coast, with very low carbon electricity (gas, hydro, wind and solar) that are great for EVs
-- The US grid is getting cleaner (both PM2.5 and CO2) faster than gasoline mpg is inceasing, and has much more potential to do that in the future.
-- US balance of trade is also a benefit...EVs use US-produced power, reducing US imports of petroleum.

Myself, I find that my local grid is somewhat cleaner than the US grid average (due to PA nukes), but buy wind power for the very reasons in this thread. The debatable factor is that I count CO2 as worse than PM2.5, so I would still choose an EV if wind was not available.

 

[jebatty]

Part of the reason for adding 5.4kw PV to my existing 6.5kw is to provide very clean fuel for my future electric car. I also have space to add more PV in the future.

 

[peakbagger]

Generally on peak and off peak generation is not included in these studies. Most utilities have to keep a large amount of generation idling over night in anticipation of the morning power demand. The power can be bought for cheap as the alternative is shutting down the plants. In Texas with a very high contribution from wind, wholesale power rates can and do go negative where the generator has t pay to get rid of power. If an electric car is charged during these off peak periods, the environmental cost for the generation is minimal as the generation is running anyhow. If on the other hand the vehicle is charged during peak power demand where the utility is on running peakers to keep up with the load, then there is potential for high emission's. As the power mix varies region by region any study has to make assumptions that negate the validity of the study. If someone used the Tesla concept of driving long distances with frequent recharges during peak periods, the emission profile is going to be different than someone who charges their car off of their PV with surplus power or off peak purchased power and avoids on peak charging.

 

[Dune]

Just a nitpick, but the main source picking up that 11 percentage point drop in coal is natural gas, and that's in part because low gas prices are leading coal operators to run plants that are still licensed less. If gas prices go back up, coal production is expected to tick slightly upwards again.

The total of all renewable sources except hydropower in the US is 6.9%:
http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_1_1

New wind solar and other alternatives come online every day.

(the amount of renewables have more than doubled in the last 15 years)

The next big push (in reality a very small push but everything helps) is the revitalization of existing but unused hydro sources at old abandoned industrial sites.
This will eventually add a few more points of the very best kind of baseline power. Additionally we are finally on the cusp of harnessing ocean power. Once that dam breaks the floodgates of clean power will be smashed open.

No new coal plants will be coming on line.

There are also new nukes supposedly under construction or at least licensing.

The message of the study is misleading at best.

I don't know whether that is Prof. Kennedy's intention or not but IMHO he provided more rhetoric for the fossil fuel camp's propaganda mill. I have little doubt that Forbes and the Wall Street Journal will feature this study with inflammatory self serving deceptive headlines giving millions of people "real" reasons to shun electric cars.

 

[Dune]

Generally on peak and off peak generation is not included in these studies. Most utilities have to keep a large amount of generation idling over night in anticipation of the morning power demand. The power can be bought for cheap as the alternative is shutting down the plants. In Texas with a very high contribution from wind, wholesale power rates can and do go negative where the generator has t pay to get rid of power. If an electric car is charged during these off peak periods, the environmental cost for the generation is minimal as the generation is running anyhow. If on the other hand the vehicle is charged during peak power demand where the utility is on running peakers to keep up with the load, then there is potential for high emission's. As the power mix varies region by region any study has to make assumptions that negate the validity of the study. If someone used the Tesla concept of driving long distances with frequent recharges during peak periods, the emission profile is going to be different than someone who charges their car off of their PV with surplus power or off peak purchased power and avoids on peak charging.

This is more than a little issue. It is clear that the vast majority of grid charging is done overnight since the Tesla model is the least common.
By displacing the wasted fuel of an idling turbine plant the carbon offset is immense.

 

[brad wilton]

in quebec our rates have gone up 10% in 2 yrs. why because government is having hydro quebec buy from private turbine companys at higher rate they don't even need the power can't even sell it, where talking millions of dollars .it's not as black and white as everybody thinks

 

[woodgeek]

I charge my EV 2-5AM during the warm weather (to extend battery life), and during the day in freezing weather (because of shorter range).

 

[peakbagger]

In theory, some aggregator would aggregate electric car owners and sell blocks of charging load to power plants. When the power plant needs load during the night, the aggregator would negotiate a low rate and if there is sudden uptick in demand, the aggregator would automatically shut down the chargers until the power demand dropped. There was a failed attempt in CA to use EV batteries connected on chargers as short term (5 minute grid support. I think the first attempt failed but expect Tesla is planning to generate revenue for selling short term grid support from their leased batteries installed in homes. All sorts of financial engineering once someone combines the internet and distributed batteries.

 

[woodgeek]

In theory, some aggregator would aggregate electric car owners and sell blocks of charging load to power plants. When the power plant needs load during the night, the aggregator would negotiate a low rate and if there is sudden uptick in demand, the aggregator would automatically shut down the chargers until the power demand dropped. There was a failed attempt in CA to use EV batteries connected on chargers as short term (5 minute grid support. I think the first attempt failed but expect Tesla is planning to generate revenue for selling short term grid support from their leased batteries installed in homes. All sorts of financial engineering once someone combines the internet and distributed batteries.

There have been other expts like this...I have a friend who ran one of these at U Del. I think the scale is not there yet, at least on the East Coast.

 

[iamlucky13]

In theory, some aggregator would aggregate electric car owners and sell blocks of charging load to power plants. When the power plant needs load during the night, the aggregator would negotiate a low rate and if there is sudden uptick in demand, the aggregator would automatically shut down the chargers until the power demand dropped. There was a failed attempt in CA to use EV batteries connected on chargers as short term (5 minute grid support. I think the first attempt failed but expect Tesla is planning to generate revenue for selling short term grid support from their leased batteries installed in homes. All sorts of financial engineering once someone combines the internet and distributed batteries.

Smart chargers would be one way to achieve this. The utility would need a server that the smart charger could connect to and ask if it's a good time to charge.

A reasonable logic for this is to let the owner to choose options like "charge now" or "charge when the time-of-use rate is below X / kWh or charge is below 50%."

However, there is not yet any standard for sharing this kind of data, and existing time-of-use billing schemes are relatively rudimentary.

in quebec our rates have gone up 10% in 2 yrs. why because government is having hydro quebec buy from private turbine companys at higher rate they don't even need the power can't even sell it, where talking millions of dollars .it's not as black and white as everybody thinks

This is happening in Washington and Oregon, too. It's a political mess that comes down to a court decision that a set of publicly owned powerlines in the region must be operated for the benefit of the investors who own the wind turbines, not the taxpayers who own the powerlines.

Adding the controllable demand of electric car smart chargers could potentially help a little bit by soaking up excess supply, but it's a highly seasonal issue. The region already had more power than it could use in the spring before the wind turbines were built. Unfortunately, the wind turbine output in these parts is heavily biased towards the springtime, just like the hydropower is. The winds are calm in this area in the late fall when we could could actually use the power.

 

[EatenByLimestone]

You guys might like this form of energy storage.

(broken link removed)

 

[woodgeek]

Sadly there is not enough pumped storage, or enough real estate to build enough new. I'll go for cheap grid batteries.

Most of this stuff was built decades ago to cope with the opposite of wind/solar intermittency....nukes don't like to throttle down. So they built a lot of these with nuke subsidy money to store excess power at night.

 

[iamlucky13]

Not just nukes, but any steam plant, including most coal and some oil plants. Pumped storage also works for storing wind or solar energy, but as you rightly point out, there's limited places to build it.

Unfortunately, batteries aren't cheaper. The best large scale batteries are just approaching the cost of pumped hydro storage.

 

[Ashful]

Not just nukes, but any steam plant, including most coal and some oil plants.

I know very little about power generation, but as an EE, I did have to take the usual coursework in controls theory. Seems to me, even with the long time constants of steam turbines, a sophisticated control system could critically throttle steam generation from coal and oil fired boilers, to meet forecast demand. Heck, even a BSEE with solid understanding of second-order systems and PID controls should be able to get pretty darn close.

 

[iamlucky13]

Yes, and they do demand forecasting and supply scheduling, but there is a margin of error both on the demand and supply side (a plant requiring an unplanned shutdown, or an un-forecast calm hitting a windfarm can cause a major disruption if some additional reserve is not kept ready to ramp up on very short notice) there is still an overall loss of efficiency from running below the optimal point and during the ramps up and down. Perhaps even more significantly, having the capacity to meet the peak daytime demand means you have a huge excess at night. Storing power is expensive, but not necessarily as expensive as building giant power plants that only run a few hours a day. The daytime peak is usually around half the nighttime minimum, and the highest peaks are relatively short.

This is part of a series of related concepts including peak shaving, load leveling, and spinning reserves:
(broken link removed to http://new.abb.com/substations/energy-storage-applications)

In a discussion with another engineer a while back, he suggested that we will probably soon start to see a slight preference for installing solar panels in a southwest orientation, because even though due south produces the greatest number of kWh, southwest best aligns with the typical peak demand in warm climates, and power generated during that time can have a high enough extra value under time-of-use schemes to more than make up for the slightly reduced output. Some also might favor southeast orientation to help deal with the typically smaller morning jump in demand.

 

[semipro]

I know very little about power generation, but as an EE, I did have to take the usual coursework in controls theory. Seems to me, even with the long time constants of steam turbines, a sophisticated control system could critically throttle steam generation from coal and oil fired boilers, to meet forecast demand. Heck, even a BSEE with solid understanding of second-order systems and PID controls should be able to get pretty darn close.

Mechanical and electro-mechanical systems generally work better and last longer under steady state conditions. Fluctuations during operation and hysteresis create many of the stresses that decrease efficiency and cause failures.