We got a solar roof system installed last October and also had a “smart” meter installed by the electricity company to measure our consumption / contribution to the grid. I ran some numbers and thought I would post them here. We installed 9.4 kW of solar panels with an 8 kW inverter. What does all this mean? Well, solar panel generate direct current (DC) and the inverter is a box that then converts this into alternating current (AC) which is what your house gets from the grid.
We just finished up our first full year after getting solar here in Northern California. I noticed you mentioned shifting your time of use in order to take advantage of your excess solar production during the day.
Here we use something called Net Metering, which involves netting out total household usage versus total solar production regardless of what was produced or used during what time of day. So on a sunny day when our panels are producing at near 100% and our household consumption is normal, the electricity smart meter on our house literally runs backwards with each excess kWh generated, turning the meter back one kWh.
Over the course of our first year with our system, sized to 108% of our average consumption, our actual total production was almost exactly the same as our total consumption, resulting in our net metering energy bill being zero for the last 12 months. We pay a $10 per month grid connect fee and that’s it.
Also, re the improvement to panel energy production density, while that is improving, I wouldn’t advise people going out and upgrading their existing system just to get the higher efficiency panels until the ones they’ve got are “worn out.” All solar panels do degrade over time, their energy production falling off a small percentage each year.
After 25 years or so this could be significant enough to warrant a replacement that would be cost effective. Before then, though, it might not make economic sense to do; and it certainly isn’t the “green” thing to do - those panels need to go somewhere, either recycling or in a landfill - either of which will have some negative result on the environment.
Solar is definitely the way to go for many households, so great to hear you’re heading there. Like you, I’m still holding out on EVs, and recent articles I’m reading indicate that’s a reasonable decision, at least for the time being.
Thanks Tom. I think "Net Metering" means different things in different places so it's interesting to hear how it works for you. Obviously I would prefer your set up (as it would remove the main driver for us to get a battery).
I absolutely hear you about replacement and issues around old panels. I think the lifespans of solar systems have increased along with their power - I believe warranties have gone up from 10 years to 25 years as standard now - and we intend to get the most out of our panels that we can. I also hear that people are adding to their solar systems rather than ripping and replacing.
Nice post and analysis, Matt.
We just finished up our first full year after getting solar here in Northern California. I noticed you mentioned shifting your time of use in order to take advantage of your excess solar production during the day.
Here we use something called Net Metering, which involves netting out total household usage versus total solar production regardless of what was produced or used during what time of day. So on a sunny day when our panels are producing at near 100% and our household consumption is normal, the electricity smart meter on our house literally runs backwards with each excess kWh generated, turning the meter back one kWh.
Over the course of our first year with our system, sized to 108% of our average consumption, our actual total production was almost exactly the same as our total consumption, resulting in our net metering energy bill being zero for the last 12 months. We pay a $10 per month grid connect fee and that’s it.
Also, re the improvement to panel energy production density, while that is improving, I wouldn’t advise people going out and upgrading their existing system just to get the higher efficiency panels until the ones they’ve got are “worn out.” All solar panels do degrade over time, their energy production falling off a small percentage each year.
After 25 years or so this could be significant enough to warrant a replacement that would be cost effective. Before then, though, it might not make economic sense to do; and it certainly isn’t the “green” thing to do - those panels need to go somewhere, either recycling or in a landfill - either of which will have some negative result on the environment.
Solar is definitely the way to go for many households, so great to hear you’re heading there. Like you, I’m still holding out on EVs, and recent articles I’m reading indicate that’s a reasonable decision, at least for the time being.
Thanks Tom. I think "Net Metering" means different things in different places so it's interesting to hear how it works for you. Obviously I would prefer your set up (as it would remove the main driver for us to get a battery).
I absolutely hear you about replacement and issues around old panels. I think the lifespans of solar systems have increased along with their power - I believe warranties have gone up from 10 years to 25 years as standard now - and we intend to get the most out of our panels that we can. I also hear that people are adding to their solar systems rather than ripping and replacing.