wayne530
New Member
- Joined
- Mar 7, 2022
- Messages
- 117
Just curious what your sizing strategy would be for an off-grid (i.e., can't export excess production), residential system. I have sufficient roof-top space to install enough panels such that all of our usage would be covered by solar production (on average - we have a large 30kWh battery bank), but that would mean significant wasted excess production in higher production months. Alternatively, I could size to minimize excess production in higher production months but that would mean buying power from the utility in lower production months, and of course all options in between.
Our average daily usage is about 16-18 kWh and I'm comparing a ~4 kW solar array vs. an ~8 kW array. January (lowest in my area) daily production would be 10kWh vs. 20kWh and July (highest) daily production would be 23kWh vs. 46kWh. Even with two EVs, we could not ever hope to use nearly 28kWh in excess per day in the summer months. I'd love not to give the utility a single dime, but it just feels terribly wasteful to have 28kWh of unused excess production.
For completeness, I currently pay 27 cents/kWh during off-peak hours (midnight-3pm), 47 cents/kWh from 3-4pm and 9pm-midnight, and 58 cents/kWh between 4pm-9pm, so it's pretty expensive to buy at the moment.
Anything else I should take into consideration? What would your strategy be?
Our average daily usage is about 16-18 kWh and I'm comparing a ~4 kW solar array vs. an ~8 kW array. January (lowest in my area) daily production would be 10kWh vs. 20kWh and July (highest) daily production would be 23kWh vs. 46kWh. Even with two EVs, we could not ever hope to use nearly 28kWh in excess per day in the summer months. I'd love not to give the utility a single dime, but it just feels terribly wasteful to have 28kWh of unused excess production.
For completeness, I currently pay 27 cents/kWh during off-peak hours (midnight-3pm), 47 cents/kWh from 3-4pm and 9pm-midnight, and 58 cents/kWh between 4pm-9pm, so it's pretty expensive to buy at the moment.
Anything else I should take into consideration? What would your strategy be?