“net metering”
The excess daytime solar power from houses could be used to charge EVs parked at workplaces and shopping centers.
To charge EVs at home typically means using fossil fuel-supplied electricity.
I think that fantasy is over with. Sure there will high speed chargers around in big box store parking lots, but the stores lease the space..
Agreed. However, in mine and my wife's case, our EV is usually charged with solar because my wife's retired and I'm quasi-retired. When I work it's usually at home. In other words, usually the EV is charged during the day.
Like FReeper JAKraig stated, it requires some project engineering or it'll cost you more than it saves you. Comment #32 details steps I took to make mine save me.
Another step I took was to have two charging circuits for the EV (dryer outlet circuits). One charging circuit is constantly powered, but not always free (like virtually all circuits in the house). The other charging circuit is intermittently powered -- only when my home battery stack is charged at least 70%. That circuit isn't always on, but when it's on it's always free (almost always). The idea is that 70% charge in my battery stack is almost always plenty of charge to power the home through the night without pulling from the grid. When we come home with the EV, if we have plenty of range left in the EV battery, we plug it into the intermittent charger. It may or may not get charge, and if charging it may or may not charge all the way to 80% (the recommended top charge state for local driving). And sometimes the EV stays parked (and plugged in) until the sun comes out the next day enough to charge the home battery stack to 70% (or whatever I configure the inverters to) and resume charging the EV. Of course, if we come home with the EV with low charge we plug in the constantly powered charger (definitely charge the EV, but may or may not add to the power bill).
Another thing is my water heater has a heat pump built in the top of it to heat the water tank. It runs at only 380W, but can take hours (if I have guests staying over I switch the water heater to use normal heat strips like a normal electric water heater, using 4kW). The 50-gal water tank is large enough for my wife and I to take back-to-back showers, and with our kids grown and moved out, we don't care if it takes hours to reheat the tank. While it's reheating the tank, the water heater's heat pump runs and pulls air in from the attic (often very hot -- a free heat source). Thus, the water heater doesn't have to run as long to find enough heat energy for the water tank. Also, the water heater outputs free cold air as a byproduct. During the warm half of the year, I duct that free cold air into an intake duct of my home HVAC. Thus, my home variable speed heat pump can stay in one of the lower speeds for a few extra hours each day thanks to the free cold air coming from the water heater.
The variable speed heat pump saves me money. The hybrid water heater saves me money. But the two work together to be better than the sum of their parts. (Project engineering)
I charge my EV at a slow speed (5.6kW). When my total load of my home with whatever appliances running at any point in time is less than 18kW, it's within the threshold of AC power that my solar inverters can provide and, thus, they don't have to pull power from the grid (assuming I have solar and/or battery power, which is always DC power). If most of the time the variable speed heat pump is in a low power, while the water heater uses low power, while the EV is charging at one of the slower settings, I'm almost always within the 18kW limit even if we're running another appliance (i.e. clothes dryer or electric stove and oven). (Project engineering)
Charging my EV is like adding a major appliance to my power load. Except that usually my EV can be charged only when there's free solar power. This is because the EV has its own battery that gets about 230 mile range (when charged to 80%, driving local driving speeds). We drive on average 1,500 miles per month on home charged miles alone (18K miles per year). That's 50 miles per day. If we come home in the EV and it's raining, usually it's no problem waiting for a sunny day if it comes in a couple of days (unless we drove a lot extra one of those days). The two-charger circuit system detailed above means it happens without us putting much thought into it. So the solar system saves me money, the EV saves me on gasoline cost, and the two work better than the sum of their parts. (Project engineering)