Thursday, August 03, 2017

Suburban 5-4-and-a-Door Solar: The First Bill

This week we received our first full bill since installing our solar array. It's strange to be excited about receiving a bill, but we were eager to see the impact of the solar array on what is typically one of our most expensive months for electricity.

The bill did not disappoint. July electricity bills in our household are highly variable due to vacations, camps, and other events that get people out of the home for long periods when the air conditioning is turned off or set higher. However, the lowest bill in recent records for July was over $280 with some exceeding $300. This month's $181 was a great improvement, even with the $2.82 penalty assessed by Georgia Power for generating our own power.

As expected, we did not make a lot on the excess power we generated. For the 166kWh we generated, we received $5.76 or about 3.5 cents per kWh. The rate charged for power ranges from 5.6 to 9.7 cents on our current plan, depending on use, so we obviously would prefer to use all of the power we generate rather than sell it back.

Here are the comparisons that matter. Since each bill is calculated over a different number of days depending on when the bill is generated, we have compared our usage and costs per day for the last five years.

In dollars, our average cost per day dropped from the $9-$10 range to $5.69. Not quite a 50% drop, but a very significant drop for a month with a lot of use.

In kWh, our average use per day dropped from the 60-70kWh range to 40.1kWh. Again, a nice drop to see in a hot month. We essentially maxed out production from the array (except when those summer storms rolled through).

What does this mean long term for ROI? It's way too early to tell. We'd like to hit 50% savings for the entire year to get our breakeven in the 10-11 year range, but that will depend on savings on sunny summer days as well as dreary winter days. The good news is that we are using almost all of what we generate and it is making an impact. The results from one month are not significant enough to determine a trend, so we'll have to keep watching for the rest of the year to get a full understanding of our breakeven point. In the meantime, it is still exciting to log into our array and watch it producing power and offsetting our usage and our bills.

For more posts about our solar installation, please click the "solar" tag below.

No comments: