What Needs to Happen Before Electric Cars Take Over the World • Hacker News Board

Re: What Needs to Happen Before Electric Cars Take Over the World

#281

Post by ajuc » Tue, Dec 19, 2017, 3:22 PM UTC

godman_8 wrote: post #274

mschuster91 wrote: post #213

Biggest problem I guess will be expanding the charger network, simply due to physics. On the country side, laying cables for 1MW peak load (4 superchargers @ 250 kW) will be expensive - the grid in rural areas is enough for some farms and small villages, that's it. In cities, electric-car chargers will have to deal with political obstacles (no one wants to sacrifice free-for-all parking spots!), in addition to the el…

Why can't this just be solved with solar panels and batteries?

That's interesting. Cheap 15% efficient solar panel produces 0.75 kWh per square meter per day in "average US location" [1], whatever that is.

Let's assume average parking space area is 10 square meters (it depends, but it's close [2]) - so that's 7.5 kWh per day.

Average energy consumption of electric cars is 11-16 kWh/100 km [3], let's assume 10 kWh/100 km - that's 75 km range for a day of standing in sun.

That's actually not bad, and should be enough for driving back home from work. Actually, why not just put the solar cells on the car and do away with the batteries (car already has them). It would be less area, but even 20 km of driving for free would be enough for many people.

Hell, I use a car maybe twice a week, usually to drive for less than 10 km. Such a car would basically drive for free for my use case :)

[1] https://dothemath.ucsd.edu/2011/09/dont-be-a-pv-efficiency-s...

[2] https://www.quora.com/What-is-the-size-of-a-standard-parking...

[3] http://pushevs.com/2017/05/23/electric-car-range-efficiency-...

Re: What Needs to Happen Before Electric Cars Take Over the World

#282

Post by anovikov » Tue, Dec 19, 2017, 3:24 PM UTC

mschuster91 wrote: post #213

Biggest problem I guess will be expanding the charger network, simply due to physics. On the country side, laying cables for 1MW peak load (4 superchargers @ 250 kW) will be expensive - the grid in rural areas is enough for some farms and small villages, that's it. In cities, electric-car chargers will have to deal with political obstacles (no one wants to sacrifice free-for-all parking spots!), in addition to the el…

But that replacement doesn't need to happen quickly, cars won't get replaced sooner well... than the cars are replaced, which is, about once in 15 years. Even if market share of electric cars in dealerships is 100%. So grid requirements will evolve slowly through about 2050, not overnight - which is hardly faster than its normal renewal rate.

Re: What Needs to Happen Before Electric Cars Take Over the World

#283

Post by _ea1k » Tue, Dec 19, 2017, 3:25 PM UTC

vvanders wrote: post #244

mschuster91 wrote: post #224

Earlier quoted context omitted.

> The USA installed Cable TV, why would charging cables be harder? Because a TV coax cable is 1cm slim and can be installed very easily. Run it over the air on poles, dig it into a small trench, run it via the sewers. Whatever fits best. A 10 kV or, worse, a 1 kA-capable 3x230V line, not so much. The 10kV (or more) line has special requirements in terms of distance to other cables, a 3x230V line at that capability is…

These arguments don't really hold up given that Tesla has already deployed a charging network really wide. FWIW all of the chargers I've seen didn't require new transformers or lines. Heck they put in 20 spots in Centralia without even digging up the road.

You know, it is funny that I have heard so many strange hypothetical against the future of electric cars that are contradicted by the current implementation of them. Its really strange.

Re: What Needs to Happen Before Electric Cars Take Over the World

#284

Post by GuB-42 » Tue, Dec 19, 2017, 3:29 PM UTC

hermenaut wrote: post #255

mschuster91 wrote: post #213

Biggest problem I guess will be expanding the charger network, simply due to physics. On the country side, laying cables for 1MW peak load (4 superchargers @ 250 kW) will be expensive - the grid in rural areas is enough for some farms and small villages, that's it. In cities, electric-car chargers will have to deal with political obstacles (no one wants to sacrifice free-for-all parking spots!), in addition to the el…

Over the next 50 years if solar roofs take off ( https://www.tesla.com/solarroof ) I don't see it being that much of a problem on the country side. We probably won't need to rebuild the entire grid, may be able to leave some part of the grid behind. May even be cheaper to do so with savings compared to the alternative options

Solar roofs are just fancy solar panels. And they wont help it there is no sun.

There are two ways of making sure you still get power when there is no sun for your panels: storing power locally and using the grid. For storage, you can have enough batteries to deal with the day-night cycle, but a week of overcast weather in the winter is likely to be prohibitively expensive. It means that the grid is necessary, and it has to be able to cope with peak load.

Re: What Needs to Happen Before Electric Cars Take Over the World

#285

Post by ajuc » Tue, Dec 19, 2017, 3:30 PM UTC

Fuzzy_Logic wrote: post #273

jdietrich wrote: post #242

Earlier quoted context omitted.

Electric cars have the potential to be a key part of the solution to load management on a fully renewable grid. The vast majority of people will usually charge overnight and don't need to regularly charge at peak times. Through intelligent charger management, you can distribute the load of charging across the entire off-peak period. The UX for this can be fairly straightforward - by default you charge at the cheapest…

Even if the expensive infrastructure was put in place to allow electric car batteries to be used as a peak load reservoir, utilities would still need to maintain traditional on demand resources, such as natural gas fired power plants. Using a large number of cars is not dependable, utilities need on demand dependability. What happens if during peak consumption in the evening winter months more people stay out late (s…

> Using a large number of cars is not dependable

It's just a matter of safety margins and probability. Traditional powerplants break too, and with enough cars the probability that enough of them wouldn't be available at once is smaller than the probability that enough powerplants break at once.

Re: What Needs to Happen Before Electric Cars Take Over the World

#286

Post by bluGill » Tue, Dec 19, 2017, 3:34 PM UTC

vvanders wrote: post #244

mschuster91 wrote: post #224

Earlier quoted context omitted.

> The USA installed Cable TV, why would charging cables be harder? Because a TV coax cable is 1cm slim and can be installed very easily. Run it over the air on poles, dig it into a small trench, run it via the sewers. Whatever fits best. A 10 kV or, worse, a 1 kA-capable 3x230V line, not so much. The 10kV (or more) line has special requirements in terms of distance to other cables, a 3x230V line at that capability is…

These arguments don't really hold up given that Tesla has already deployed a charging network really wide. FWIW all of the chargers I've seen didn't require new transformers or lines. Heck they put in 20 spots in Centralia without even digging up the road.

Tesla has only added a few chargers though, and they carefully selected the locations to be places where there are newer upgraded power lines. If electric cars become common chargers will need to be everywhere including older neighborhoods where the power lines are not up to the load.

Re: What Needs to Happen Before Electric Cars Take Over the World

#287

Post by greedo » Tue, Dec 19, 2017, 3:34 PM UTC

fergie wrote: post #66

> "But the automakers’ existing expertise — building internal combustion engines — will no longer give them a competitive edge." Interesting- this would mean that the real innovation in cars comes _after_ electric drivetrains have become the standard, when any moderately capitalised company without substantial experience of internal-combustion motors can create their own take on a car with any kind of new features th…

Thinking that the ICE is a competitive advantage/disadvantage is what has led to Tesla struggling with building the Model 3. The competitive advantage held by the existing automakers is based around building cars cheaply; in quantity; and in quality. They also have established brands that inspire tremendous loyalty, and they have dealerships that offload a lot of the support issues.

When electric drivetrains become the standard, nothing will be different. These automakers will still have these advantages over upstarts.

Re: What Needs to Happen Before Electric Cars Take Over the World

#288

Post by secabeen » Tue, Dec 19, 2017, 3:46 PM UTC

kozak wrote: post #260

mschuster91 wrote: post #234

Earlier quoted context omitted.

> if the charging times are rapidly decreased Charging times have an upper bound: physics. 250 kW is an insane amount of power and still you'd need around half an hour to fill a 100 kWh battery, to get even close to the 5-10 minutes of charging like at a gas station you'd need megawatts of peak power... and as there are two steps of conversions involved (grid => HVDC => battery voltage), even with 99% efficiency you…

Is there really a HVDC to battery voltage conversion step? I thought the whole point of quick charging is that you get exactly the DC that the battery needs right from the charger.

Actually, the superchargers take AC from the grid. The equipment at the supercharger consists of a rack of AC to DC converters run in parallel. That creates the DC that is delivered to the batteries at about 400 Volts.

Re: What Needs to Happen Before Electric Cars Take Over the World

#289

Post by enraged_camel » Tue, Dec 19, 2017, 3:50 PM UTC

jdietrich wrote: post #242

mschuster91 wrote: post #213

Biggest problem I guess will be expanding the charger network, simply due to physics. On the country side, laying cables for 1MW peak load (4 superchargers @ 250 kW) will be expensive - the grid in rural areas is enough for some farms and small villages, that's it. In cities, electric-car chargers will have to deal with political obstacles (no one wants to sacrifice free-for-all parking spots!), in addition to the el…

Electric cars have the potential to be a key part of the solution to load management on a fully renewable grid. The vast majority of people will usually charge overnight and don't need to regularly charge at peak times. Through intelligent charger management, you can distribute the load of charging across the entire off-peak period. The UX for this can be fairly straightforward - by default you charge at the cheapest…

I was talking to a professor of electrical engineering who performs research on the electric grid. She said that while in theory it is possible to configure cars to charge themselves when electricity is cheapest, currently residential utility plans don’t adjust pricing based on time of day. Your electricity bill’s tiers are based on your total consumption.

Edit: lol, I get downvoted for relaying what a professor of EE told me. Stay classy HN.

Re: What Needs to Happen Before Electric Cars Take Over the World

#290

Post by kozak » Tue, Dec 19, 2017, 3:52 PM UTC

secabeen wrote: post #288

kozak wrote: post #260

Earlier quoted context omitted.

Is there really a HVDC to battery voltage conversion step? I thought the whole point of quick charging is that you get exactly the DC that the battery needs right from the charger.

Actually, the superchargers take AC from the grid. The equipment at the supercharger consists of a rack of AC to DC converters run in parallel. That creates the DC that is delivered to the batteries at about 400 Volts.

As far as I understand, the car asks the Level 3 charger for a certain amount of volts and amperes, and the charger delivers exactly what the car needs (being able to vary the parameters for each type of car - and yes, those Level 3 DC chargers are big, complex, and expensive). Then the current goes directly to the battery. And this is why the charging gets so fast: there are no intermediate steps. The car just needs to provide cooling for the battery and control the charging process.