Today I met Boyd the potato farmer, a nice, well-spoken man who was inquiring about my bike and interested in solar energy in general.
“I spend $1600 per month on electricity, mostly on irrigation pumps, I’d probably have to cover my whole 160 acres with solar to generate that,” he laughed.
“Oh no,” I told him, “It wouldn’t take so much. Let me calculate it for you. When you’re figuring solar you always figure energy per day because we get the sun’s energy per day. So $1,600 per month divided by 30 days is $53 per day. Now, you’re probably paying about 10 cents per kilowatt-hour so $53 would be 533 kilowatt-hours per day. It’s pretty sunny here so we’ll say for easy math you get 5.33 peak-sun hours. I know you get that because Portland gets 4 and it rains all the time over there. So, to get 533 kWh per day would require a 100 kW solar array.”
“How big would that be?” Boyd asked.
“Well,” I continued, “one kilowatt of solar takes 80 square feet, so 100 kW would take 8,000 square feet.”
“Is that all?” Boyd’s interest was peaking, “so 10 feet by 800 feet along my south fence line would do it.”
“Yes,” I declared matter of factly.
“Well then how much would it cost?”
“About $250,000,” but the Federal government kicks in 30% so your part would be about $175,000.”
“That’s amazing,” said Boyd.
Tracking completely with me his final question was,
“At $1,600 per month how long would it take to pay that back?”
“$175,000 divided by $1,600 is 65 months, a little over 5 years,” I answered.
“Wow, if it really works out that way every farmer in Idaho would go solar.”
“Every farmer should,” I replied.