Chisue, we have an 11 yo Prius, and I love it. Not fully electric, but the gas mileage is great. 42 mpg on the highway. Can't answer your questions about the batteries, but if my car is any indication, they last a long time.

The answer is very much so, to this extent- Conventional power plants don't cycle from high to low and back to adjust to day vs nightime power demands. They're either fully on or off and they remain fully on overnight. Electricity generated through the night is unused and wasted. Charging cars (or doing anything else) during those hours uses that power with no net increase in production cost or emissions. Environmentally and financially, it's free, and there's plenty of capacity available to charge tens of thousands of cars overnight with no need to boost production. Of course solar units don't produce power when it's dark but those so far aren't part of base load production.

The Prius is a fantastic car, so too the other models Toyota makes with the same hybrid technology. I believe it's the #1 car sold in California, you see them in large numbers everywhere. My wife drives one and loves it. But a Prius is not an electric car. They do make a plug in model that will take a small charge good for the first 25 miles or so before the gas engine kicks in - that seems like a waste to me and for the premium of a few thousand $$ they charge, it's hardly worth having.

I didn't get a good look at it, but I saw an electric car the other day, and it had a sign on it that said, "Zero emissions", or some such, I think.

I had the feeling that that would be true only if they had a cycle inside that one could pedal and use its generator to charge up the battery, without using any externally sourced power.

Would have liked to have had the opportunity to leave a note with such a message under the windshield wiper ... with my phone No., email address, or such included, so it was not just a snarky comment that didn't allow for rebuttal/discussion.

ole joyful

The limited research I've done before has found a LOT of disagreement on it.

You should also look at the cost of maintenance and the materials used for maintenance over the next 10 to 20 years (or however long they last). For example with a conventional auto you have to change the oil 33 times in 100,000 miles. Not only does the oil have to come out of the ground, it has to be refined, bottled in plastic bottles, delivered to the wholesaler, retailer, and car. Also with a fossil powered car there are any number of failures that can happen that can't happen to a battery with an electric motor. Fossil motors have transmissions that need to be serviced and repaired while electric motors have no transmission. Fossil driven cars have a powerful braking system while electric cars can use the motors to slow. They might still need a braking system to stop, but it would not need to be heavy duty. Fossil cars have a cooling system that would not be needed in an electric car.

The entire system for electrical is so simple it sorta has to be a win. You have batteries, motors, and a brain.

I have not completed efficiency comparison between a fuel power auto versus an all electric auto, but it seems that the battery fed electric vehicle is not as efficient. The comparison is difficult because there is no simple direct comparison. My approach is to calculate and amount of BTUs required to push an average car a mile. A calculation for an assumed average gasoline powered car can be readily made. If the car gets 27 miles per gal, and the fuel is 10% alcohol plus 90% gasoline, the number of BTUs is known and the calculation can be made.

The problem is calculating the amount of BTUs for an electric car. BTUs are burned in the power plant to make electricity to charge the batteries. The problem is finding all the efficiencies needed to make the calculation. The overall efficiency for a fossil fueled power plant might be 50%. This is to convert fuel BTUs to electric power as delivered to the transformer yard. The power is transformed to high voltage for transmission (up to 500,000 volts). The power is run through another set of transformers to a lower voltage for the main distribution line (near 27,000 volts). This might be a line that powers and entire village. It is transformed down again to about 2400 volts for the local street lines to households. Another transformer drops the voltage to 120 V for household use. This is done through a center tapped transformer. There are two 120v lines running the house (one from each end of the transformer winding. The center of the winding is the common return.) Next, there is the charger and battery efficiency. Transformers are not 100% efficient and there are transmission losses along the lines. The power has been run through at least 3 transformers and line losses should be accounted for. The charger efficiency may vary from 80 to 95 % efficiency; the battery's charging efficiency is a big unknown. The charging efficiency for a lead-acid battery is about 75%; About 25% of the charging energy is lost. Another loss occurs when power comes out of the battery. Finally, there is the efficiency of the electric motor and its controls. The overall system efficiency is all these efficiencies multiplied together. The anticipated loss between burning the fuel in the station to the output of the car's motor is expected to be considerable. I have my doubts that it will compete with the gasoline engine. In other words, I expect that it will require more BTUs per mile for an electric car than for the gasoline engine. (To be fair, the amount of BTUs required to deliver the fuel to the car should be added to the gasoline engine requirement.)

An electric car will still need full capacity mechanical brakes. Electrical dynamic braking is effective down to about 15 MPH and then regular brakes are needed to complete the job. The reason full capacity brakes is needed is this: Dynamic brakes can fail. If one of the solid state power devices blows out, dynamic braking is lost. If this happens at 70 mph, the mechanical brakes must be sized to handle the job, When dynamic braking is present, the wear of the mechanical brakes will be greatly reduced.

One consideration is that gasoline engines are so terribly inefficient that much of the fuel purchased is wasted. At least with power plants, the fossil fuels used are used in a much more efficient way, and presumably more cleanly. To the extent that the power plant is hydro or nuclear or solar or wind, there will be no greenhouse gases generated.

Here's Sierra Club's take on it.

Thank you all. I see the benefits depend a lot on the source of fuel to produce the electricity that will recharge the vehicle. It seems to come back to the need to eliminate fossil-fueled electric plants... which leads into dangers of obtaining fuel by fracking...and nuclear energy. (Sigh.)

Thanks for the good links, Rob and Annie.

I appreciate Elmer's comments about the inefficiencies of the dual-power vehicle. "All or nuttin'" should be the call.

We have a 'perfect' roof for solar panels, but our city has no permitting in place to install solar. Idon't think we will live here long enough to get into that, but it irks me. We have solar on Maui; it powers landscaper carts, pool and hot tub heaters, and all the 'in common' lighting.

Maybe seeing more electric cars will raise public awareness of clean energy? (What becomes of solar-power storage batteries?)

Hmm, chisue. I wasn't suggesting hybrids like the Prius are inefficient. They are very efficient in a sense because they get exceptional gas mileage, especially in city driving when the engine spends long periods of time "off". They're not electric cars, that's all.

PS - did you know that un-electrified trains that run in the US are diesel-electric hybrids and have been for decades? They use the same basic technology as auto hybrids like the Prius. Diesel engines turn generators, charging batteries that then power electric motor driven drive wheels. Why? Because as with cars, it's more fuel efficient to use the internal combustion engine to generate electricity to power electric motors for propulsion.

We have a 'perfect' roof for solar panels, but our city has no permitting in place to install solar.

My understanding is that nobody can prevent you from installing your own solar panels. HOAs used to be able to prevent that, but times have changed. I believe this is a federal thing and not a state by state.

An electric car will still need full capacity mechanical brakes.
Electrical dynamic braking is effective down to about 15 MPH and then
regular brakes are needed to complete the job. The reason full capacity
brakes is needed is this: Dynamic brakes can fail.

Good points. There are three ways to stop an electric motor. One is to reverse the direction of rotation. This could bring the car to a stop, but not hold it in place. Another is to disconnect the drive power and allow the motors themselves to generate power and then dump that power into a resistor. Another is similar but you use the generated electricity to recharge the batteries. By far the most effective braking is to dump to a resistor. That method is so effective that it can break other parts of the drive system. I suppose a system could be designed to incorporate all three methods to achieve higher reliability in breaking. But in the systems I've seen a mechanical brake is still available.

The charger efficiency may vary from 80 to 95 % efficiency; the
battery's charging efficiency is a big unknown. The charging efficiency
for a lead-acid battery is about 75%; About 25% of the charging energy
is lost. Another loss occurs when power comes out of the battery.
Finally, there is the efficiency of the electric motor and its controls.

You're touching on sacred ground - sacred to the Tesla company. All the secret research is going into NOT lead acid batteries and into new batteries, charging, and discharging technology. Battery, charging, and discharging efficiencies are getting better by leaps. Fuel-air efficiencies are getting better by baby steps.

To be fair, the amount of BTUs required to deliver the fuel to the car should be added to the gasoline engine requirement.

To be still fairer, you have to consider BTUs required for the entire life cycle of the car. You can't just build a car and call it a day. In addition to the fuel and supply line for fuel, there are parts and maintenance and an entire supply chain required to deliver the parts and maintenance. The amount of lifetime maintenance needed for an electric drive is minuscule compared to that for a fueled motor.

According to this study, the main problem with electric cars appears to be the impact of EV battery production.

.........the study has calculated that a fossil fuel vehicle can
currently drive for more than eight years before it reaches the same
environmental impact of a Tesla. For the Nissan Leaf, with its smaller
capacity battery, this figure comes in at three years.

Mia Romare, one of the two researchers of the study, hence concludes:
‘Unnecessarily large batteries weigh more on the environment. One
should therefore consider whether one can manage with smaller
batteries.’

According to the study, only 10-20% of the environmental impact is
generated by the source extraction of raw materials such as lithium from
the mines. The main environmental impact comes from the processing of
these raw materials and the production of the lithium-ion batteries in
factories, which accounts for around 80% of the environmental impact.

https://www.autovistagroup.com/news-and-insights/swedish-study-calls-smaller-ev-batteries-finds-tesla-more-polluting-8-year-old