Well my fears came true, and today I left Tier 1 and entered Tier 2, so my cost per kilowatt doubles from about 20 cents to 40 cents. This means my commute is twice as much as it was for the past 25 days. So be it. 2 days are a weekend and I can drive my wife’s car all weekend but I should do the math and see if her MPG work out better than paying for power at .40/kWh.
Anyhoo, a friend at work is thinking of fixing up his solar and wanted to know how much I’m solar I’m getting versus how much I’m paying for. I had not checked for a while, so I ran an export from my power company to get what they were charging me for (the yellow in the first chart below), and the green is the solar I’ve generated each month from a small 2.5/kWh system of 10 panels. If I add the 2 together, I get my family’s full power consumption, but as you can see I’m not billed for the full consumption, since the solar is sold back to the power company and I only pay the net of both. Obviously I’m not going to cover all my monthly electricity consumption with my system, but what I can do with it is stay in Tier 1 rates at 20c/kWh longer than I would if I didn’t have solar. Whats important to me are the 2 lines. Those lines represent Tier 1 and Tier 2 rates of electricity. Ideally I’d like to spent the entire month below the first line (Tier 1). For a few months I am, but for many others I exceed Tier 1, and in July and August I surpass Tier 2 and enter Tier 3. The beauty of my small system is that it artificially keeps me in the lower tiers for longer. The way I look at it is if I didn’t have solar, I’d be paying tier 2 rates almost every month for sure, and Tier 3 for 2 months of the year.
What could i have done differently?
When I estimated my solar consumption, I didn’t have an electric car. If you’re gonna go solar, plan to get a system big enough to cover your current + anticipated future costs. After I added the electric car (what you’re seeing below) is about 100 kWh/month (estimated) more than what I forecast when I’d built it. It’s not a YUGE difference, but again, it could keep me in Tier 1 and 2 longer. Then ultimate question becomes if I’m saving more money overall having a small system than the monthly amount I’m still paying off on the loan, which is a topic for another article.
The chart below shows what percentage of my home’s electricity is covered by my solar system each month.