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1. There are any number of ways to compare an electric and a hybrid car. Price, availability, fuel cost and availability, public perception, power, range, size, applications might be some but you asked about environmental “consequences.” “Consequences” is a term that has pejorative connotations. If you wanted to use a more neutral term you may have referred to environmental “effects.”1

   An electric car has an electric motor that can use electricity from any number of sources. It may be transmitted to it like some trains or some cars that travel on roadways through induction pick up. It may be created on board with a fuel cell or even a gasoline engine and it may then be a series hybrid or it may be stored on board using batteries, ultracapacitors, or flywheels. Since you didn’t specify I will assume you refer to the talked about, battery electric vehicles (BEV as electric trains may be the most common.)

   A hybrid can have many different configurations. A velomobile (recumbent trike with a full body fairing) with an electric assist motor is a human/electric “hybrid.” But assuming the most talked about would be a gasoline/electric hybrid like the prius which is a parallel hybrid. Here we are not talking about a vehicle that is plugged into the grid for power. All of its driving energy comes from gasoline. The gasoline powers the engine and some of that power is stored in batteries that can be used to power the vehicle, mostly at starts. The batteries also can recover some of the energy used for regenerative braking. For an interesting take of this see the best answer (first and then look at mine) : http://answers.yahoo.com/question/index?qid=20100328095652AAyt5fz

   A parallel hybrid uses its gasoline engine to achieve about twice the fuel efficiency as a strictly gasoline powered vehicle the same size. A pure electric vehicle of a similar size would be approximately 5 times as efficient: http://serieshybrid.com/FreedomFormula/images/Drivetrain_Comparison.pdf

   Efficiency is significant as it shows you how much fuel is being “wasted.” The wasted fuel is still producing pollution. For example a gallon of gasoline produces about 20 lbs of CO2 when burned. In a car that gets the average 20 miles to the gallon every 20 miles a gallon is used and 20# of CO2 is put in the air. A hybrid may go twice as far so every 40 miles will put 20# of CO2 in the air. A gasoline car is only about 15% efficient so a hybrid car is about 30% efficient overall. By saying that an electric car is 5X as efficient we are giving it a minimum of 75% efficiency and it should be able to go at least 100 miles on the equivalent energy as in one gallon of gasoline. Many do but one stock tesla roadster went 313 miles on a full charge which is significantly more.

   So the electric car will produce 1/5 the pollution as a gasoline vehicle or less than half that of the hybrid. Right? Not exactly. Because while the hybrid that does not plug in is producing pollution the operation of the electric vehicle produces no pollution. AH Ha! You say, but what about the terrible coal fired power plant that produces the electricity. This is known as the “long tail pipe argument” and it fails for several reasons. First this is a comparison. We are comparing gasoline in a hybrid to electricity. So after comparing the vehicle operation to each other we should compare the Refinery, transporting fuel etc to electrical production and transmission costs etc. It turns out that refineries use energy to produce fuel. So much in fact that with the higher efficiency of an electric vehicle it can travel further on just the energy used to refine gasoline than the gasoline powered can go using the gasoline. Some of that energy is in the form of natural gas. In the US less than 48% of our electricity is produced with coal and this number has been declining as renewables take more of a market share. Coal power plants are from 30 to 60% efficient. Even considering transmission losses the combination with the pollution free efficiency of electric vehicles is better than gasoline vehicles, even a hybrid.4

   Hybrid vehicles represent a slight improvement in efficiency while purely electric vehicles are truly a difference in the environment. An electric car powered from stationary solar cells would produce no environmental pollution from its operation or the source of its power. This is why the city of London is moving to purely electric vehicles: http://www.independent.co.uk/environment/climate-change/mayor-unveils-plan-to-turn-london-into-electric-car-capital-of-europe-1666129.html