A study of switching the nation’s 278 million cars and trucks to electricity provides a stark reality check to policy-makers at all levels of government.

The American Transportation Research Institute, a nonpartisan think tank, laid out in detail the many challenges posed by weaning the nation’s transportation fleet off petroleum. It also explains why, when politicians talk about making the big switch, they are being unrealistic in the amount of time and money such a massive undertaking will require.

For example, in California 35% of new cars must be powered by electricity or some other non-petroleum fuel by 2026. That percentage will increase to 68% by the year 2030 and 100% by 2035. Connecticut, Maryland, Massachusetts, New Jersey, New York, Oregon, Rhode Island and Washington state have similar 2035 deadlines, according to ATRI.

Half of all new heavy-duty trucks sold in California must be electric by 2035.

The ATRI study’s conclusion: Good luck.

California doesn’t have enough electricity now, let alone in 11 years. The state currently uses 247,000 gigawatt-hours of electricity a year and imports 20% of that from out of state. Much of that is from coal-fired generators in Utah.

Two-thirds of all of California’s electricity is non-renewable, meaning it comes from coal, natural gas and nuclear plants. The main nuclear plant, which produces 8.5% of the state’s power, is scheduled to be decommissioned next year.

Electricity is also expensive. Californians pay an average of 22.3 cents per kilowatt-hour, the second-highest rate in the nation, according to ATRI. San Diego’s power rate is the highest, 47.5 cents per kilowatt-hour, and San Francisco pays 35 cents.

That’s just California. Nationwide, the challenges are even more daunting.

For example, it will take an estimated 40.3% more electricity than is now generated to run the all-electric fleet of cars and trucks.

And it will take more distribution lines — lots more.

And it will take many more mines globally to produce cobalt, lithium, graphite, nickel and the other raw materials that go into batteries, which wear out and must be replaced every six years or so.

Then there’s the cost. Electric cars are expensive, but electric trucks are really expensive, an estimated $400,000-$500,000. That’s about three times the cost of a new diesel truck, according to ATRI. Also, because those batteries are heavy, the trucks won’t be able to carry the same amount of freight. That means a need for more trucks and drivers.

The logistics of keeping 12.3 million electric trucks charged are also daunting. Combined with federal limits on how long drivers can be on the road, it’ll take something like 313,000 parking spaces with chargers nationwide.

There are many more challenges, but you get the idea. What the politicians want is impractical, expensive and would take several miracles to accomplish.

We’re not against switching some of the fleet to electricity, hydrogen or another yet-to-be identified fuel as a way to reduce the amount of carbon dioxide going into the atmosphere.

However, we balk at the way the politicians want to do it, which can best described as a helter-skelter fire drill.

The initial push should be to convert commuters to electric cars. Their ranges are limited and they can be charged at home. Though many are expensive, lower-priced models are coming out.

Similarly, electric delivery trucks that return to the shop each day for charging might some day be practical.

For long-distance drivers or truckers, electricity won’t be practical or affordable until more power plants, high-voltage lines and chargers are built.

That will take many decades and untold trillions of dollars.