With a 13-year-old car in the garage and electric vehicles finally reaching the mainstream, the time has come to carefully consider an electric car.

The surprising thing, after running the numbers, was how the assumption that EVs cost more didn't turn out to be true. The other big surprise is that buying no new car is now an option on the table.

There are now lots of electric cars to choose from, but the easiest way to compare them to a conventionally powered car is to pick two cars that are basically the same. That led to the smallest of Volvo's crossover SUVs, the XC40.

There's a gas version and an electric version and the only noticeable difference is the weird faux grille Volvo put on the front of the battery-powered version, called the XC40 Recharge.

To get closely comparable vehicles you have to load up the gas-powered XC40 version with a few costly options, although in Minnesota heated seats might not be considered frivolous anymore. The sticker came to more than $49,000, including a $1,095 destination charge. Sales tax took the full cost to north of $52,000.

The Recharge version, with sales tax, comes to about $64,000, an estimate that doesn't include $900 to wire the garage for a charger.

There's a tax credit to offset some of that, though: $7,500 in this case.

Yes, there are less expensive cars, but the average new car price as of the latest Kelley Blue Book data exceeds $43,000. That old LaSalle that ran so great can't be found in the new car market anymore.

A big factor in total cost, of course, is what a car is worth at the end of five years. This turned out to be a fascinating question, because from Kelley Blue Book data and other estimates, it looks like electric vehicle values slip faster. That's partly explained by no federal tax credit in the used car market.

Both cars in this analysis will decline in value a lot over five years, but the conventional version should be worth about 40% of the MSRP while the Recharge value drops to just 35%. That's a big advantage for the gas-powered car.

The cost advantage flips to the EV after maintenance and fuel costs, though, even with the manufacturer paying for some maintenance.

The conventionally powered car gets about 25 miles per gallon, so driving 12,000 miles in a year burns nearly 500 gallons of premium gasoline. I don't know how to forecast gasoline prices, or I'd be living the lavish lifestyle of the retired commodities trader, but I guessed an average of $3.72 per gallon over five years.

That brings the total fuel cost to nearly $9,000.

The Recharge takes about 40 kilowatt hours of juice to drive 100 miles, and each kWh costs about 13 cents each, for about $3,200 in total fuel costs. But that's not the whole story.

The gas-powered car will spew more than 9,000 pounds of carbon dioxide every year.

If that seems like a lot, know that one of the odd parts about climate science is that a gallon of gasoline that doesn't weigh much more than 6 pounds generates close to 20 pounds of carbon dioxide when burned, as all those oxygen atoms now combined with the carbon do add up.

The carbon dioxide seems to just disappear, so it's not obvious that it costs anyone a nickel.

The cost of this pollution is known as an externality, meaning a cost or benefit that got shifted onto somebody else. It happens all the time, and a great example of a positive externality is getting your COVID-19 shots, benefiting the whole community.

This is the economic thinking that leads to policy ideas like a carbon tax, which hasn't gone anywhere here. An interesting question, though, is whether the owners of gas-powered cars are really avoiding that cost. They live here, too.

But what's it really cost? The Biden administration pegged the cost at $51 per metric ton after taking office, and it seems likely to increase it soon. There have been far higher estimates, too.

Even at $51 per metric ton for the first year and $85 for every year thereafter, these costs aren't enough to make the difference.

There's still another wrinkle, though, and that's a how the power coming from that new charger in the garage wasn't produced carbon-free. The provider in St. Paul, Xcel Energy, generated about 62% of its power in our region free of carbon and it's doing better at eliminating carbon every year.

Yet in the first year the EV still gets tagged with the cost of more than a ton of carbon dioxide pollution.

Other costs were too hard to estimate to even include, like additional tailpipe emissions and even particulates kicked into the air by driving. There's a cost for these, too.

Bottom line: The XC40 Recharge wins the cost-of-ownership battle at about $10,600 a year while the conventional gas-powered XC40 will cost more like $11,400.

That makes the choice pretty clear — unless either number seems so big some will wonder if they've already bought their last car.

A person still needs to get around, though, so how about one of those electric power-assisted bicycles? No one needs to train hard for months to quickly get one going 25 miles an hour.

I put a Specialized Turbo Vado 4.0 e-bike into the cost-of-ownership spreadsheet, with a retail price of $4,000.

One big difference is how maintenance will be a much bigger share of the total ownership cost. No one gets 40,000 miles on a set of these bike tires, and just about everything else on this bike will get replaced at least once. You can have a philosophical ship of Theseus discussion over whether it's even the same bike in five years.

The real challenge came from estimating costs for when there's no good option but a car, like a weekend trip Up North. The best idea turned out to be an Hourcar membership that lets the member take a shared car out of town for $45 a day.

A loaded-up cost-of-ownership estimate for a very fancy e-bike came to around $2,200 per year.

Is biking even realistic for someone who got a beloved Chevy Chevelle at 16? Those winter bike commuters, bundled up like deep-sea divers, never look like they're having fun. Yet quietly gliding by them in a fancy electric car costs $29 a day.

All of us have probably said, "I don't care if it's free, I'm not doing it." Yet there always seems to be a number that might make a once-unthinkable idea look pretty good.