April saw a massive flurry of orders for home solar panels in California, due to a massive rule change on how homeowners are compensated for their excess solar power. (I ordered panels before the deadline to take advantage of the above rules.) Under the new rules, most customers will find their solar panels much less lucrative and it will take longer for them to start saving money on the power grid. One way to fix it is to have a home battery, and even having an electric vehicle is a form of home battery. But would it be possible to help your neighbor charge their EV to get this benefit if the logistics were easy to do?
The math of solar power and the grid is complex. It was simpler under the old rules. During the day, your solar panels typically generate more electricity than you use, and you feed it into the grid for others to use. When the sun stops shining, you get power from the grid. The old net metering system simply subtracted how much you spent from what you brought in (cubed by what time of day you did it). If you took out as much as you took in, your “net” was zero and you paid almost zero for power. The grid was a perfect, almost free battery that you could put your extra energy into and take it out later.
That’s great and makes it easier to go solar, but the power companies argued it wasn’t fair, and the California PUC agreed. In his world, the value of power changes all the time. The old rules allow you to turn off the power at noon, when there is a large surplus and the price is low, and turn it off later when the price in your markets is higher. So under their new rules, if you turn off power, they’ll pay you just the same wholesale rate they’re paying others, and you’ll buy any extras you need at the higher retail rate. These rates are very different in part because in California, most of the cost of electricity is a delivery charge (paying grid companies for having the wires) and not a generation charge, where you pay the remote power plant. When the power plant is on your roof and using its output, there is no delivery charge, making solar a great deal when you use it.
The new rules may be fairer to the utility, but they will discourage the installation of solar power, which is not what we want from a public interest standpoint. Power companies fear that eventually there will be so much extra solar power from homes in the middle of the day that they won’t be able to handle it. It already creates a minor crisis at 6pm when all those solar panels go off and other plants, mostly fossil fuels, suddenly have to ramp up rapidly to meet what is usually the peak demand for the day in hot weather.
It seems likely that in the future, with lots of solar power, the wholesale cost of spare solar power at 11am could drop extremely low. The only trade-off is that briefly, just as the sun is going down, the rate can be very high, but that’s because the sun is fading and therefore most panels don’t provide much. Even today, some estimates suggest that solar panels will take 3 times longer to “pay for themselves”, which means lowering your grid power bill by as much as they cost, compared to the old rules. However, after that point there is a profit, so they are still worth putting up. We may see more solar panels installed to face west or southwest in the future, to catch the evening light. This reduces their total generation, but can increase the value of the power they produce.
An owner can fix this with a battery. They can put their surplus solar into a battery and extract it later, using much less of the grid. However, batteries are expensive and wear out as you use them. The grid is willing to pay a lot for power from a battery just as the sun goes down, so it can be lucrative – for those hoping to use car batteries as “V2G”-style home batteries, this is the only time in the day it makes the most sense to do it, although many cars are still on their afternoon commute.
Car charging during the day.
An EV has a very large battery, and unless you’re taking long trips, it doesn’t matter when you charge it during the day. Most people charge at night because the car is parked, they are asleep, and energy at night is cheap. It’s the obvious choice, except for the fact that there’s no solar power at night.
For those with a car that doesn’t take a trip and stays plugged in at home, the best plan will be to charge it with whatever surplus solar power you have. There are a variety of small companies that will use the data from their solar panels to tell the car to only charge with that energy, and soon Tesla cars will be working with Tesla’s solar panels to do just that. In addition, several power companies work with customers to change the charging time for cars when the power company has surplus solar power, although the incentives are currently less.
Most of the time the driver doesn’t care much, although if you’re planning a trip in the morning, you don’t want to find that your car didn’t charge overnight because you were waiting for cheaper surplus solar power in the day. The biggest burden is just remembering to tell the system to sometimes make sure the car charges at night. Because night power is cheap, there isn’t much incentive to do so, which probably needs to change. Right now, the “my car is full every morning” approach is simple and appealing, but it’s more based on fossil fuels.
Commuter cars must be plugged in at the office and passenger lots. That works even better if those lots have solar panels. In France, new laws require new parking lots to have solar panels.
Some of these problems could be solved if there were an easy way to sell my excess solar power to my neighbor, particularly to charge his car. When it comes to providing power to a neighbor, almost no transmission equipment from the grid is used; in fact, my immediate neighbors on the same transformer have a direct connection to me. Today, under the new metering rules, a solar owner can be offered just a few cents/kWh under the new “avoided cost” rule that you only pay the wholesale price. But my neighbor is paying full retail cost and would happily pay me something between retail cost and avoided cost, and the power company deserves only a small fraction because hardly any of their equipment is involved.
It’s not possible to do this today, nor would it be easy if I were to set up complex billing with my neighbors, but independent virtual power companies could be enabled to do this, taking a cut of course. The good thing about solar panels is that you can easily control your output, so you can ensure that you’re never putting more power into the grid than your neighbors or larger grid are requesting, and you’ll never overload your equipment. On some days, your neighbors can take all your surplus and pay you decently. Other days, you may need to sell it to the network at the avoided low-cost value. Perhaps in the future the avoided cost will drop to zero and you will stop sending power, or consider getting a home battery.
As more people install solar power, it will become more difficult to sell it to your neighbors. As such, all customers would not be treated equally, which may upset some. Company parking lots surrounded by solar-powered residences could spend that extra, or vice versa. As long as the network had the capacity to move the surplus, it would, and when it was economical, it would upgrade. Energy storage companies would be happy to buy any surplus they can get at a good price.
If a car owner wants to add a vehicle to the network, they will need to program it correctly. They must be plugged in to recharge the battery from 9 am to 2 pm to get the solar surplus. They must then be plugged into a special two-way V2G socket during the super demand peak (from just before sunset to around 8pm) when spot power rates are highest and will justify the additional drain on the vehicle’s battery. car. If the two-way plug is in your home, they can use it from 3:00 pm to 9:00 pm to offset their own usage during the peak rate period, which can be more than 50 cents/kWh in California. For V2G, what matters is the difference between the price of the power that went into the battery (ideally cheap surplus solar from your own panels) and the cost price avoided when you sell the power. On hot summer nights, this cost can be quite high.
If all this sounds complex, it is. The market opportunity will be for companies and systems that make everything easier and bring lower costs to consumers without them having to think about it too much, allowing them to be greener at the same time. To do that, PUCs must facilitate these companies and require established monopoly electric companies to work with them in a way that is fair to all. EVs require us to expand the grid (though no more than it has in the past to meet other new needs), but expanding with solar is important this time around, and EV charging is the ideal application for solar. , if we make this easy. do and help people save money.
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