Electric cars are the future. Is producing electricity to charge them cleaner than gasoline?

Factual Questions
21

Since we’re talking about adding and upgrading a bunch of capacity, the solution seems like it should be “install the chargers at the location where the cars are during the cheapest electricity”. This also likely solves a lot of the apartment building problem, too. Apartment buildings don’t have to charge every car every night because many of those cars are commuting to business lots and sitting there while the sun is at its brightest. Put chargers in the lots!

This requires some coordination and alignment of incentives, but it’s not a fundamentally difficult problem.

I expect that there are probably already commercial parking lots in busy downtown areas that advertise car charging as part of the service they provide and use cheap solar power to charge. As more people get electric cars, more lots will charge them!

22

How much battery current goes to running a heater during cold weather and running A/C in hot weather?

Do current photo sells on the roof charge batteries for household use, or sell the current to the utility company?

23

Not to mention it is also a waste product, which they have to - let gas into the atmosphere, burn off at the source, or utilize- of which utilize is the best for the environment.

24

It depends on the car, whether it has a heat pump or not, and just how hot or cold it is. Here in Canada in cold winter weather you can lose more than half your range. This is due to not just heating the cabin, but also heating the battery, plus winter tires and snow have a lot more rolling resistance than summer tires on pavement.

That’s why I won’t consider an electric car with less than 300 miles of range. I don’t want to find myself in a snowstorm in -30 weather in a car that will only go 100 miles on a full charge, and if it got stuck or in a traffic jam I’d still be depleting battery just staying warm. That’s a recipe for constant range anxiety.

To be able to use your car battery to power your home or sell to the grid requires hardware most electric cars don’t have. The only ones I personally know of are the Ford F-150 Lightning, the Rivian Truck and the Hyundai Ioniq 5.

But solar panels on the roof of your car produce very little power. They won’t really add much in the way of range, and their best use would probably be to run a small fan in summer to keep the interior cool so you don’t need as much AC when starting out.

A 1m^2 solar panel in ideal conditions might produce about 200 watts at the equator. As you go north from there you lose solar insolation and the panel’s horizontal orientation gets less efficient. I’m guessing you’d be lucky to get 100W out of such a panel at noon parked in the sun in the northern US.

A Tesla uses 26 kWh to go 100 miles, so it would take such a panel about 260 full sun hours to enable 100 miles of driving, and a full day of charging would let you drive a little over two miles. Also, at say 20 cents per kWh, the electricity you save after 10 hours of charging in noontime sun would be worth about twenty cents.

Thi# ignores charging efficiency, and whatever power the vehicle uses when parked. A typical EV will lose about 2-3% of its charge per month when not being used.

In the real world, panels lose efficiency over time, get dirty, and the vehicle may be parked somewhere where it doesn’t get full sun. Also, clouds will cut down your power substantially, and power generated is lower in the morning and late afternoon when the sun is lower. So probably divide all those numbers in half for closer real world numbers.

Solar power for a typical car just isn’t worth it, other than for trickle charging a battery and running a cooling fan on the interior in summer. For a smaller vehicle that’s used rarely and for short periods, it might work. A little utility vehicle that sits for weeks or months at a time and then is used for a few chores around farm or something would maybe never need charging. But if you wanted that, it would be smarter to build a car cover with solar cells on top. Then you don’t have to lug them around and you can keep the vehicle itself out of the sun.

25

Don’t people have a bit more than one square meter of solar panels?

26

I assume we are talking about solar panels mounted on the roof of a car. If you cover the entire roof, maybe you can get 2 m^2. So double those numbers if you like. Still not enough for any practical range extension for most people.

27

No, I’m speaking of people who put them on the roof of their house. The few people I’ve spoken with do not charge a room full of batteries to operate their house, they sell the current to their electrical utility.

28

Oh, sorry! I misunderstood the whole scenario.

Whether you can sell power back to the grid, and at what price, depends on local regulations. Some places won’t allow it at all, some will but only pay you the spot price of electricity (which, as we add solar, will very soon be zero or even negative when the sun is shining), and some have feed-in tariffs with set prices to encourage solar adoption, the cost of which is transferred to other ratepayers or taxpayers in general.

Do not believe the numbers for breakeven that solar providers will sell you. They are almost always based on wildly optimistic estimates. I had a provider here claim payback in 10-15 years with the subsidies, but when I looked at actual generated power in our area it didn’t come close to their estimates. There was no breakeven at all.

One of the reasons solar is hard to scale is that if you have feed-in tariffs they become extremely expensive, and if you don’t you’ll soon find that the grid doesn’t want any more solar power and will pay you zero for it, or even charge yoh for taking it because they have to pay someone else to take it from them. Germany and Ontario already have those problems, and they are up to only a few percent of grid solar.

One way around the spot price for daytime power is to install something like a Tesla powerwall. Buy power from the grid during the day when power is cheap, and charge your battery with solar, then run off your battery in the evening when power is more expensive.

Today power in no -solar areas is usually more expensive during the day, but at a certain percentage of solar adoption that will flip.

One other thing to know about solar power on your house - it won’t help in the case of a grid failure. If the grid goes down, by law your solar system has to go offline so you don’t feed power back into the grid when workers might be fixing it. To me, this negates one of the biggest reasons for owning a solar system.

To avoid this problem you need an automatic transfer switch that will disconnct your house from the grid if the grid fails. You’ll also need something like a Tesla powerwall or other large home battery to buffer the power. That can add $10,000 or more to,the cost of installation.

Some EVs can take on the battery role. The Ford pro charger for the F-150 lightning will disconnect your house from the grid and switch your house to the truck battery if the power goes out. If power is up, your solar system can help chargebthe truck. It ks a pretty sweet system if you need a truck and want an EV.

29

If the EV runs the house when the power goes out, I’ll have a dead car in the morning. :slight_smile:
We did a lab in a solar course in undergraduate school. This was several years ago, so we were heating water. I drew Fargo, ND. It failed miserably at running the whole house, and even worse at twice that size. I did best with using it to run half the hot water in the house.
We “bought” the equipment with a loan and did a spreadsheet on how long it took to pay for it.

30

Do you have an explanation/citation for this? My understanding is that power is significantly cheaper almost everywhere at night because the demand is much lower. In a hypothetical future where a significant portion of the grid is solar, this might change, but I don’t know that that anywhere is actually there yet. You mentioned Germany, so I tried googling around and found this which documents a German consumer’s electricity price at different times of day, and it seems like what I’ve understood is normal - it peaks in the afternoon and then again in the early evening, with the middle of the night being by far the cheapest.

31

It’ll take an awful lot more solar than we have now for “during the cheapest electricity” to be during the day. Sure, thanks to solar, the potential supply is a little higher during the day, but the demand is a LOT higher.

The idea isn’t to run the whole house when the grid is completely out. The idea is to get you through maybe an hour when power is more expensive than usual, or your demand is unusually high, and then replenish the battery in future hours (but still before the car is needed).

32

That’s true, but I expect there to be an awful lot more solar in the future. There are already geographic areas where the cheapest electricity is midday due to solar. I expect that will describe more and more of the planet over time, although probably not everywhere.

But even if it doesn’t, it still makes sense as a solution for places where it’s true.

33

This is scheduled when electrical rates are higher? That would work.

34

I agree with this being the key. I still don’t get why the Democrats haven’t gone all in on the nuclear fission train.

35

Here in Australia it is pretty clear that cheap overnight power is going away. Renewables are a big part of why. Cheap power is a function of generation plants that can’t adjust their output in a short time frame, and so need someone to buy their power 7x24. Mostly coal and nuclear. Natural gas powered turbines can spin up to deliver power in minutes, as can hydro. Wind and solar can reduce power delivered as needed, but obviously can’t ramp up past the available wind or sun. Power regulation on the grid must occur in time frames down to seconds. There is actually a market for such short term power. For very short term power regulation traditionally the grid depended on the huge power stations to be able to ride out the fluctuations literally through the inertia of the generators. So the term inertia is used describe this regulation. Here in Oz, Tesla have supplied a couple of large installations of batteries and inverters that have now pretty much taken over this market. Apparently the first company that installed one repaid it in a bit over a year.

The usual answer here with domestic solar and a battery is to join a virtual power grid. This is a commercial arrangement where a company controls your battery and solar within limits to essentially play arbitrage on power prices. Typically you get about a $1500 subsidy for your battery if you join. But you can also make money on the power you sell back. The battery makes it possible to sell your energy at a better price than the spot price when you generated it.

As I said, this is a work in progress. It provides a template of some existing and successful strategies that can be applied into the future. If electric cars become the norm one can see how the nature of the grid and generation strategies can change to take care of car’s needs and also do so with renewable power.

36

True.

Eh, depends on what numbers they give you. I know someone in Maryland who has a rooftop solar power system and the numbers he gets are pretty close to what he was quoted. For him it has been an excellent investment and has done exactly what was promised.

YMMV. Exactly what tax breaks and other incentives you get varies quite a bit from area to area.

True.

Most people (at least that I have talked to) do it to save money in the long term and/or to do their share to provide green energy and reduce our dependence on nuke plants and fossil fuels. In most areas, power outages are rare enough that they do not negate either of these, at least not for most people.

A lower cost option would be a backup generator. It costs a lot less than the batteries that you would need though you still need to pay for the transfer switch. And again, power outages are rare enough that this usually isn’t much of an issue for most people. Most home solar users don’t have any sort of backup system for when the power goes out.

37

The reason is because the transition to more solar means more generation during daylight, and less at night. This is already driving daytime prices to zero in some places:

There is a $200 million solar farm in Australia that has now been shut off 34 times because the grid couldn’t use the power.

This is happening even though solar only makes up 9.9% of Australia’s energy. This is the fundamental problem with solar: At certain times it makes a lot of energy, but it is unreliable and intermittent. And Australia is probably the best place for solar power.

Germany has had a number of days when it went over 100% of demand in production of renewables, and solar only makes up 8.2% of their energy.

Solar power without battery storage maxxes out at a pretty low number. Building additional capacity after that doesn’t help much. at least in summer. That’s why Australia is working hard on grid scale battery storage, but it’s really expensive and only helps shift supply by a half day. That would maybe double the amount of solar the grid could absorb.

But that gets you to the third problem: There are times when it stays cloudy and calm for days or weeks. So you have to maintain a complete secondary power infrastructure for those times. Currently, countries like Germany and other countries heavily dependent on wind and solar buy power from their neighbors when this happens. If everyone transitions there will be no neighbors to buy from. At that point, we will stall out at under 30% wind/solar, with solar making up maybe 10% and wind the other 20%.

Without a feed-in tariff, people in Australia will be paid nothing for their solar power on sunny days, or may be even charged for the grid accepting it. The factbthatbthe spot pricenis going to zero during summer days is the market’s way of saying there is no need for more solar power, at least on those days. There will be more days like that as more solar is added.

This creates a problem for electric car charging, as the old paradigm of cheap nighttime power is flipped by both less supply at night and more demand for power.

38

An F-150 Lightning battery will power a typical house for about three days. And it allows you to set how much battery depletion will be allowed before it shuts off, so you can make sure to have enough range for the morning commute. You can aldo get a backup generator for the truck that looks like a toolbox in the bed, but with which you can run your house indefinitely. Or a job site.

Well, both. if we keep going down the path we are on, shutting down baselod and dispatchable power for intermittent renewables, our electricity is going to be a lot less reliable. I’d like to be prepared for that.

To entice people to install solar, Ontario had to offer a feed-in tariff of 80 cents per kWh. That’s a crazy high price for electricity, and it’s being subsidized by taxpyers. It’s also unsustainable past a small number of people selling power. Without the tariff, they likely won’t break even on new solar installations.

I will start a thread later showing the reality of solar in Canada and other northern countries. For starters, our ratio in daily solar energy between winter and summer is about 5:1 where I live. That means you either have to overbuild your solar capacity to the point where you are shutting down most of it in summer, or you have to have an alternate energy source for winter. Another problem is that we can go weeks or even months where there is little solar energy at all because of clouds and snow. And we’re starting from a best case where we only get a little more than half the solar energy received at the equator because of our latitude.

I am buying a backup generator next month. Youncan even get away without a transfer switch by not plugging it into the house, but instead unplugging critical appliances like the Fridge and furnace igniter and plugging them directly into the generator.

This isn’t going to work in California in the future, however. In an act of legislative stupidity they have banned small gas generators under 25hp. The ban doesn’t take effect until 2028, but what an amazingly stupid thing to do, especially considering how unreliable their power is becoming.

This is ostensibly to curb emissions, but given that these things only run when the grid is down, it can’t be significant. And people trying to work on remote job sites are just screwed, I guess.

39

Marylnd has a very generous subsidy program. If I understand it correctly, Solar Renewable Energy Credits (SRECs) are issued to renewable energy systems every t8me they generate a MWh of power. You don’t even have tomsell the power to the grid - a solar hot water heater wualifies,

The SRECs are sold on the market, with the government fixing the price at the beginning of the program at $400/MWh or .40 per kWh, declining every year until it’s about .05 per kWh.

If your friend got in on that program in 2013, It’s no wonder why he was happy. He was probably getting paid three times the amount for electricity generation than he was being charged for consumption. Future solar systems won’t be so lucky: the program srops the price of SRECs to $50 after 2023.

In Maryland you also get a $1,000 rebate for installing a rooftop solar system, and the feds have incentives that will reduce the price another 26%. Also, you get a break on your house taxes.

Maryland also lets you ‘bank’ the excess energy you make when you don’t need it, and then you don’t have to pay to draw from the bank. That’s on top of the per-kWh SREC you get. Or, you cn sell the power to them at sport prices, I think.

That’s an awfully tilted playing field, and these subsidies will go away as more people buy solar, because they are really expensive. If I lived in Maryland I’d install a solar syatem too. Same woth Ontario. But that’s not because solar is cheap energy, but more because install8ng it is a ticket to government money, But that doesn’t make solar inexpensive in general, it just means that solar owners get a lot of government money to incentivize them. That will not scale to everyone.

40

I knew I’d find a relevant thread without starting one.

This video is, in part, a demonstration as to why electric cars aren’t mainstream just yet. TL : DW - a Finnish resident found out that a new battery for his Tesla would cost 20,000 Euros (about $22,000US), so he had it towed to a quarry and blown up with 30kg of dynamite.

And a second “making of” video.