Say power costs 25¢/kWh. That's $2 per year per watt of standby power. Adjust to your local prices. So that'd take 30 years to pay back. Or, with discounted ca

Say power costs 25¢/kWh. That's $2 per year per watt of standby power. Adjust to your local prices. So that'd take 30 years to pay back. Or, with discounted cash flow applied... Probably never.