Alternative Energy at Stonybrook Ranch
The lure of clean and silent solar energy is very seductive.
I also just want to control my own destiny. Living in California we have experienced many blackouts
just from the state's inability or unwillingness to develop power sources to meet demand. Living in
a rural area, we also experience many power failures due to weather, trees falling on the lines and
a host of other reasons.
A few years ago I started examining the case for solar electricity, with an eye toward moving off the grid, or at least setting up an intertied system with battery and propane generator backup. I have a large south facing hillside ideally situated for solar power. It seemed a natural solution.
I started examining the numbers. Stonybrook Ranch uses a lot of electricity. In a given year, it is easy to use 20,000 to 30,000 kWh. With extreme conservation, I have managed to keep usage below 18,000 kWh the last two years, but that level of usage impacts the lifestyle seriously. Six hundred dollar monthly power bills are not uncommon.
With all this money going toward the local power company, it seemed a natural that Solar might make sense. Except we are talking about a very big solar installation. To fully understand the issues, we must understand the political environment first. The cost of electricity is highly variable under the local rules. Power is priced in five tiers based on zip code and season. It also depends on whether you have electric heat or other heat. Under these rules, local electricity can average anywhere between 12 cents per kWh and 52 cents per kWh. The cheaper local electricity costs, the less sense Solar makes. The crossover point is somewhere around 20 cents per kWh. With Solar power you install the system and sit back and enjoy "free" power for the rest of your life. So the high up front cost must be amortized over the life of the system, or the owner, whichever is shorter. With a 20 year horizon, solar can usually come in somewhere around 20 cents per kWh.
Depending on the size of the system and installation costs, the cost per kWh and the time horizon can both be reduced. My goal was to meet 100% of my needs, with a ten year horizon. This meant a system with about 100 panels at 120 watts each, for a peak output power of 12.6 kW, yielding on average 18,000 kWh per year, at an installed cost of well over $50,000, with a net cost of around 20 cents per kWh amortized over 20 years.
If I could get the cost to 20 cents per kWh on a ten year horizon, I might have a business case I could live with, but at the current numbers, I just can't make a convincing case to go Solar.
I built an elaborate spreadsheet to examine the situation. At fairly regular intervals, I re-examine the prospects
using current component pricing. Prices continue to improve, and I hope that some day we will be able to justify
the investment. But for now, extreme conservation, minimal lifestyle, and the local power company makes the most sense.
Since I have put so much effort into the spreadsheet, I decided to make it available here for others considering the
same choices to download and use. Click the link at right and download the Excel Spreadsheet.
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