I know very little about today’s climate actions despite routing for them, so I just want to take an opportunity to better understand them. How some things may just be temporary solutions or revolutionary ones.
I do not want climate change debates, I just want to know if powering electric cars has its trade offs or are really going to help.
In: Engineering
There are many other sources of power than just coal and gas. You’ve also got solar, wind, hydro, nuclear and geothermal. So, switching to electric vehicles might put more demand on coal and gas power for now, but the hope is that government regulation and private companies will force a shift towards renewable and green energy sources. And in the meantime, one electric vehicle charging to 100% does *not* cause a coal plant ten miles down the road to suddenly put out more emissions than it would have otherwise. The point here is that even if emissions *do* go up from coal and gas plants, it will still be a lot less than if we just keep using gas and diesel cars which are *very* polluting.
If the electricity to charge the car comes from fossil fuels, then yes, there is some waste. But the pollution generated in order to make that amount of electricity is still far lower than the pollution generated by a gas- or diesel-powered car.
Clearly this is not a perfect solution, but it is a significant step in the right direction. As more and more people buy electric cars, the technology will continue to become increasingly efficient.
Even if all the power used to charge them came from burning fossil fuels, they’d still be more efficient per unit than an internal combustion engine *and* they have the benefit of reducing air pollution in populated areas. As it happens, though, increasing portions of most industrialised countries’ electrical supplies are generated from renewable sources, and the closer that number gets to 100%, the “cleaner” electrical cars get.
There are some trade offs. Yes, electric vehicle owners are still getting that energy from somewhere. But there’s a few major benefits to having cars be part of the electric grid instead of hundreds of individual motors.
Even if an electricity producer is burning gasoline or diesel for power, it’s likely less polluting than individual engines. Controlling emissions and peak efficiency is easier for one purpose-built engine instead of having hundreds of smaller ones in various states of repair, idling, or running at inefficient rpm’s.
Additionally, it’s much quicker and more cost effective for grid-scale power-producing companies to pivot to renewables and wean themselves off of old, more polluting technologies. Household owners can get solar…but that’s the only viable option, and either expensive or not viable for many situations.
The average efficiency of cars on the road today is less than 20%. That means that less than 20% of the energy in a pound of fossil fuel is used to move the vehicle down the road, the rest is waste heat, mostly out the tailpipe.
Power plants that use fossil fuels are about 40 to 60% efficient (and higher) at converting the fuel into electricity.
When you account for the losses in transmitting the electricity via the power grid, the losses in the car charger, the losses in the motor controller, the losses in pulling electricity from the battery and the losses in the electric car’s motor… you still will move the electric car further down the road for each pound of fossil fuel burned in a power plant than the same pound burned in gas powered car.
Additionally, for each pound of fuel burned in a power plant there is significantly less greenhouse gasses produced, because the power plants have far better pollution controls than a gas powered car.
So the electric car, even if charged using a coal fired power plant, goes further per pound of fuel than the most efficient gas powered car available, AND each pound of fuel burned makes significantly less pollution.
There are really 3 answers to this question.
1 – You might not be using a source that pollutes. Maybe you get your electricity from solar, or hydroelectric. This is not a very satisfying answer because it doesn’t apply to everyone.
2 – Large power plants are much more efficient than a car engine. If you burn 1000 gallons of gasoline at a powerplant and send it to 1,000 cars, you’ll get more miles than if each car burned just one gallon of gasoline.
3 – Electric cars have regenerative brakes. Regenerative brakes are great. Imagine you’re riding a bike down a hill and then up a hill… it’s much easier if you can build up speed and then coast up the hill, only pedaling a little. Well, regenerative brakes are something like that – recapturing energy and then letting you use it later. Regular brakes on cars just turn the energy to heat – like riding a bike down a hill, stopping at the bottom, and having to pedal back up. You don’t get to reuse any of your old energy. And theoretically you could just put regenerative brakes into gas powered cars… but then you would need to load up the car with batteries, and then you’d have a hybrid vehicle.
So, #2 and #3 definitely have a real impact for everyone, even if #1 only impacts some people.
1) gas cars are 25% efficient while power plants are 50% efficient
2) buying a new electric car adds a new load to the grid, which requires new power plants. All of the power plants being installed (in America) are solar or wind
3) electric cars are going to be useful for helping achieve 100% renewable grid by controlling charging to match the supply of solar and wind, helping to keep the grid balanced.
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