Technology2 mins ago
Why Are Electric Cars Seen A S The Holy Grail?
7 Answers
they are a waste of 80% of the energy used to generate the electricity, Hydrogen is even worse, yet they keep on telling us lecky is the way to go.
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It's a throw-away question, but deserves a thoughtful response.
It's largely about emissions and pollution. Virtually all global legislation is driving vehicle makers toward electric drive-trains.
It is primarily legislators pushing this, not the vehicle makers.
The old way of measuring emissions was the New European Driving Cycle (NEDC). From 2021 we will transition to the World Light Vehicle Protocol (WLTP). This essentially forces vehicle makers to include a large number of electric vehicles in their line-up and to ensure that the high-volume sales are in electric types.
When you say 80% of the energy is wasted, you may want to clarify that. It appears to be a number plucked from thin air - certainly it's not one I recognise.
A modern high-pressure diesel engine (in a car or truck) with intercoolers has a thermal efficiency of around 45% (petrol engines are worse). That means over half the energy in the fuel is wasted as heat before you even think about engaging the clutch and driving down the road.
In the expected electric car model, the energy is derived from non-fossil sources, such as off-shore wind farms; hydro-power or geothermal energy. It is converted into electricity and then transmitted to the vehicle and stored in batteries (or other systems).
It can then be used to power the vehicle. At motorway speeds, around 50% of the energy in the battery is used to overcome aerodynamic losses (drag from wind resistance) around 20% is lost from the internal friction in the tyres as they roll along the road and the remaining 30% goes on things like air-conditioning, lights, inefficiencies in the motors and charging system.
Braking is ignored in this because we expect most braking to be regenerative, recovering the energy taken to accelerate the vehicle.
Electric vehicles put out far less NOx and SOx pollution; do less to poison the air with no PM2.5 emissions, need less maintenance, do not need lubricants, oil changes, air filter changes; catalytic converter upgrades. And are quieter for those who live next to busy roads.
This is why 'lecky' is the way to go. Cleaner, safer, less polluting.
The last pieces of the jigsaw is cost and a refuelling infrastructure. As prices come down, there will come a time when it simply makes sense to buy electric vehicles, rather than fossil-fuel powered ones.
When that time comes - probably in less than 10 years – people will simply vote with their wallets and choose electric cars rather than diesel or petrol-powered ones
It's largely about emissions and pollution. Virtually all global legislation is driving vehicle makers toward electric drive-trains.
It is primarily legislators pushing this, not the vehicle makers.
The old way of measuring emissions was the New European Driving Cycle (NEDC). From 2021 we will transition to the World Light Vehicle Protocol (WLTP). This essentially forces vehicle makers to include a large number of electric vehicles in their line-up and to ensure that the high-volume sales are in electric types.
When you say 80% of the energy is wasted, you may want to clarify that. It appears to be a number plucked from thin air - certainly it's not one I recognise.
A modern high-pressure diesel engine (in a car or truck) with intercoolers has a thermal efficiency of around 45% (petrol engines are worse). That means over half the energy in the fuel is wasted as heat before you even think about engaging the clutch and driving down the road.
In the expected electric car model, the energy is derived from non-fossil sources, such as off-shore wind farms; hydro-power or geothermal energy. It is converted into electricity and then transmitted to the vehicle and stored in batteries (or other systems).
It can then be used to power the vehicle. At motorway speeds, around 50% of the energy in the battery is used to overcome aerodynamic losses (drag from wind resistance) around 20% is lost from the internal friction in the tyres as they roll along the road and the remaining 30% goes on things like air-conditioning, lights, inefficiencies in the motors and charging system.
Braking is ignored in this because we expect most braking to be regenerative, recovering the energy taken to accelerate the vehicle.
Electric vehicles put out far less NOx and SOx pollution; do less to poison the air with no PM2.5 emissions, need less maintenance, do not need lubricants, oil changes, air filter changes; catalytic converter upgrades. And are quieter for those who live next to busy roads.
This is why 'lecky' is the way to go. Cleaner, safer, less polluting.
The last pieces of the jigsaw is cost and a refuelling infrastructure. As prices come down, there will come a time when it simply makes sense to buy electric vehicles, rather than fossil-fuel powered ones.
When that time comes - probably in less than 10 years – people will simply vote with their wallets and choose electric cars rather than diesel or petrol-powered ones
I see what you are getting at.
This is the phrase 'thermal efficiency'
It means the maximum possible energy you can get out of a heat engine (such as a power station or a diesel or petrol engine).
You take the highest temperature in the engine (Tmax) and the exhaust temperature (Tmin), both measured in kelvin (Centigrade plus 273).
The formula is (Tmax-Tmin)/Tmax.
This gives the thermal efficiency of the engine.
As noted in my earlier post, it's around 45% for modern Diesel engines (and power stations). The mechanical efficiencies of a conventional vehicle are similar to the numbers given for an electric drive train.
But surely you are arguing in favour of electric drive trains. These old-fashioned petrol engines are appallingly inefficient.
This is the phrase 'thermal efficiency'
It means the maximum possible energy you can get out of a heat engine (such as a power station or a diesel or petrol engine).
You take the highest temperature in the engine (Tmax) and the exhaust temperature (Tmin), both measured in kelvin (Centigrade plus 273).
The formula is (Tmax-Tmin)/Tmax.
This gives the thermal efficiency of the engine.
As noted in my earlier post, it's around 45% for modern Diesel engines (and power stations). The mechanical efficiencies of a conventional vehicle are similar to the numbers given for an electric drive train.
But surely you are arguing in favour of electric drive trains. These old-fashioned petrol engines are appallingly inefficient.
But aren’t we producing pollution making the batteries in the first place. What is it that’s required at the moment “ Lithium “. Isn’t that a decreasing resource? What are they going to need when it does. What about infrastructure. Where’s the charging points. Will you have to drive to the nearest one every time you plan a trip.
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