Here's when solar panel owners (and everyone else) should charge

[mburtsvt]

In California w/a solar set up. Retired and do all of my charging during the day. I don't want to send any power production up stream - it, (for the most part) goes into the Mach E.

Sponsored

 

[ricksta6]

Since I have had solar panels for a year, and my new MME will be charged primarily at home (I’m a low-milage retiree), I thought I’d share what I learned about the “greenest/cleanest” time to charge. I live outside Chicago and my solar system is on a Net Metering arrangement with ComEd. This means that at any given moment in time, if my panels are producing more than the house is using, the excess is sent up to contribute to the energy in the grid. When my bill is computed for a month, my actual usage is subtracted from my generation, and the excess I contributed is credited and “rolled over” to the next month. It continues like this monthly, until each April when any excess credits I have are zeroed out, and the annual cycle begins again. My system went live in February 2020. Since then, I have always out-produced consumption (measured by month), so my electric bill has been about $16 each month (the amount ComEd collects just for fees associated with my being part of the grid–no expense at all for Kwh used.) Since the cloudy weather last month had my production behind my consumption, I will likely be running down my rolled-over credits near to zero by the time April’s zeroing-out occurs. That’s just right!


While many of you have electricity plans that make overnight energy use rates lower than daytime, you choose night time charging to save money. For me, the money is the same no matter when I charge. I asked my son, who works in the energy industry–specifically with generation & transmission–if he could research and tell me when I should charge in order to have the most green/clean impact. The answer is a bit counterintuitive, and surprised me abit, but the explanation makes sense; it goes like this:

There is a quickly growing number of wind and solar contributors to our grid (including my rooftop system). All that clean/green energy is creating a lower demand for Kw’s from the coal/gas/nuclear plants. The grid, in fact, uses those clean sources first, then draws the needed difference from the coal & gas-fired and nuclear plants. These fueled generation plants actually have to use more fuel for each additional Kw produced.

Here’s the key: If I charge my car during the day (when my solar panels are generating Kw’s), I am lessening the clean/green solar contribution I make to the grid, and ensure that those dirty plants need to produce more during the day, when their additional production requires more fuel burned per Kw. If I charge at night, I’m tapping into power from those plants, but at a time they are using less fuel per Kw generated. (That point is, in fact, true for all of you who pay the same rate no matter the time of day you choose to charge. So night charging is more eco-friendly for you, too!) My solar panels are actually having a greater positive impact on the environment by replacing dirty daytime energy production than they would if I first tapped them for my EV charging. So, the cleanest/greenest time for someone in my situation is to charge at night–even though that’s not the time my panels are generating power. And for those who pay the same rates night-or-day, you should also charge at night when each Kw you need is being created with less fuel than during the daytime.

May I ask what Solar company you used? I'm in the area and currently evaluating options. One company I spoke with said they have a way to eliminate the connection charge with ComEd, and ComEd has confirmed the ability exists. The company only shares how to do it with their customers, though. Sounds iffy but might be legit.