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Comment by sandworm101 | Hacker News Reader

I have done the math, several times. The last time was to plan a hypothetical solar "highway gas station" capable of charging 100 teslas EVs per hour 24/7/365. Assuming flat ground at Vancouver's latitude, it came to a solar farm approaching square kilometers/miles in scale.

10kwh x 100 x 24 = 24,000kwh Solar panels nominaly produce 1000kwh/m so 24,000m2 of panels... if facing the sun perfectly during normal day/night cycles. But non-equator latitudes need far more land than that because the sun isnt directly overhead, plus winter/rainy days... it is a massive solar farm (and a massive battery) just to replace an average highway gas station.

Given that any future 2-lane highway might see a couple thousand thousand EVs each hour, each needing charging every couple hundred miles, the number and size of solar charging stations per mile is crazy.

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Don't do the math for homeless people. Most people live in homes. Homes usually have electricity, unless you live in a 4th world country. All buildings have electricity. Just park and plug in.

You need to go to a gas station BECAUSE there is no supply of gasoline straight to home. Homes have electricity. Even in sub-Saharan Africa, South Sudan, Yemen, remotest village in India. I don't know where you live, but if your home doesn't have electricity, your country has bigger problems to deal with than buying Teslas and DC Fast Chargers.

Highways. Highways need to support people traveling beyond the range of thier vehicles, be that a car or bus/truck. People could also eat and use the bathroom at home, but highways must still make space for restaurants and restrooms.

I ran into that problem during covid. I had to do a few work-related 1000-mile drives and they had closed most all the restrooms!

And my home is also home to a few hundred other people. Installing enough chargers for all our cars would require a massive grid upgrade that our city would never support. Not everyone lives in a suburb.

Highways often have powerlines nearby at least every now and then. With those you can take power from roofs many kilometres away!

And what you say about apartments is wrong, it’s definitely not impossible. I’ve heard of plenty of apartment blocks installing chargers, they have load management systems to manage the load and believe it or not, not every single apartment occupant will need to charge their car every day at exactly the same time as everyone else!

My building looked into it (a complex of several buildings sharing one giant underground carpark). Installing 300 chargers (one at each spot) would cost millions and take years to radar and cut the channels in the concrete. Even if done, the city connection to the facility would need a million-dollar upgrade too going all the way to the local substation. And then the local fire department had an opinion: they were not happy at the concept of 300 EVs in one underground structure. There are no rules limiting such things today (also on car ferries) but we are one bad fire away from some firecode regulation about EVs underground.

> Installing enough chargers for all our cars would require a massive grid upgrade that our city would never support

Do you not have an ovens? Or electric shower? Mine use 7kW, same as the car charger.

Except not every home has a driveway. With on street parking the norm in many places. Trailing a lead to your car on the other side of the road is frowned upon

Streets have streetlights. Streetlights are on poles. Poles have electricity that lights need. Utility can add chargers. Magically, the problem is solved.

Streetlights are low power.

Car chargers are high power.

For example https://electricbrighton.com/news/considerations-for-lamp-po... says charging times are 18 hours, which is hardly overnight.

Plus you couldn't do it anywhere where thieves steal copper. Car charging cables would quickly become a theft target.

Thats 18 hours if your battery is at 0%.

Most people drive 20 - 40 miles/day, hardly 10% of the battery. You will be fine.

You could also charge at work. They should have more than lamp posts.

I drive 90-130 miles a day and charge every night using the same power my oven pulls. It costs me 3 cents a mile, or equivalent of about $1 a gallon. It takes about 4 or 5 hours.

> Plus you couldn't do it anywhere where thieves steal copper. Car charging cables would quickly become a theft target.

Are you from the past? This simply doesn't happen. The reality is millions of people drive electric cars, and while there are some issues - mainly around the minority who don't have their own driveway, and the tiny numbers who drive over 70,000km year, it simply works.

People certainly steal diesel though.

I've done the math. The average car in Canada does 11,000 miles a year. A Tesla isn't great efficiency, it uses about 3.5 miles per kWh. Throw in inefficiency of charging and you're talking about 3MWh per car per year, and with about 25 million vehicles that means about 75TWh a year

Travers Solar in Alberta generates about 2.5TWh a year from under 14 sqkm.

Build 30 of them and that's 400 sqkm.

A 20sqkm by 20sqkm solar plant would power every car and light van in Canada forever (setting aside seasonality).

Factor in lower generation in December, you'd need 10 times that amount of solar, about 70km by 70km, 5000 square km.

That's less than 1 quarter of 1 percent of the land in Alberta alone.

(Of course you wouldn't put it in one location, it would be spread out across the country)

Funnily enough 5000 square km is about the total land use of Canada's oil land use (surface use)

You'd have a lot of excess power in the summer -- you'd be generating 650TWh of excess power a year

Lol, 11,000 is for all the city-bound teslas that only drive from suburb to the office. Actual average car use is closer to 25,000km/year (15,000 miles is the us average). But cars are not all road users. The "100 teslas/hour" standard is to accomidate trucks too.

If you are planning infrastructure like highways, national averages are irrelevant. It is the same debate that Hertz had when it dropped teslas: charging infrastructure is local and rental car locations (airports) cannot support the needed power density.

The math is already done: https://news.ycombinator.com/item?id=49952816

Averages are meaningless. You need to understand trips.

28% of trips are under a mile, 52% under three, 64% under five, 79% under ten, 93% under twenty-five, and 98% under 50 miles.

Only 0.8% of the trips are over 100 miles!

> Lol, 11,000 is for all the city-bound teslas that only drive from suburb to the office.

Most countries have electricity at home and at office. They can charge at both locations. If you are still using kerosene lamps and haven't started using electricity at home, you have bigger problems than charging infrastructure.

You provide no evidence of the number of cars or the kilometres driven

23.5 million light-duty vehicles

https://www150.statcan.gc.ca/n1/daily-quotidien/241021/dq241...

If each one were to drive 25,000 km (way higher than the NJC assume on https://www.njc-cnm.gc.ca/s3/d896/en, way higher than the insurance complanies say is the average - https://affiliatedinsurance.ca/blogs/how-average-mileage-per...)

It would require electricity to provide for 587500 million km of driving each year, that's about 118,000 million kWh, or 118 TWh.

Your statement

> 10kwh x 100 x 24 = 24,000kwh Solar panels

Is tricky to understand what you are on abbout as it's not clear what on earth you mean by this as solar panels aren't measured in kWh. kWh per year perhaps.

You are talking about delivering power to a specific location, not generating power. This is an argument from a decade ago, reality has proven that isn't a problem.

For what its worth, I drive over 30,000 km a year and very rarely use a public charger.

> Factor in lower generation in December, you'd need 10 times that amount of solar, about 70km by 70km, 5000 square km.

Or, convert the solar energy to heat, then back to electricity at 40% round trip efficiency. Needs only 2.5x the solar (or less, because some solar goes directly to the users without long term storage). The heat is very storable at scale, even for seasonal storage.

> Funnily enough 5000 square km is about the total land use of Canada's oil land use (surface use)

Please also consider land for biofuel/biodiesel.

1 in 3 acres of Canadian canola (amounting to roughly 7 million acres of farmland) goes directly into producing feedstock for the global and domestic biofuel markets. https://www.canadiancattlemen.ca/daily/conservatives-diesel-...

For 7 million acres (Canadian acres - 16% Capacity Factor)

Annual Electricity Generation (16% CF): ~4,467 Terawatt-hours (TWh/year)

National Scale Comparison:~7.4× Canada's total annual electricity consumption (~600 TWh/year)

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