Puglogic, that incentive is amazing! We just had our system installed this week and our Xcel incentive is $0.02/kWh. Way less than your 15 cents. Still worth it for us though as I'll spell out below.
A lot of people have been asking for an in depth analysis of the costs for a system so here is mine for the 3kW system we just installed:
For reference: we live in Denver, gas heat furnace and water heater, electric stove, electric clothes dryer. Currently, our electricity costs 11 cents per kWh but we were paying extra to get our energy from wind (b/c Colorado gets about 70% of its electricity from coal) so that cost became 13.2 cents per kWh.
The electric company gives us a $0.02/kWh incentive for each kWh generated and we also benefit from net metering (in the summer when we generate more than we use, we can bank a credit to use towards our bills in the winter, when we use more than we generate). So we get $0.152 from lower bills and incentive for every single kWh generated.
Given our location and house orientation (mostly west facing roof mount) etc, NREL's PVWatts calculator (
http://pvwatts.nrel.gov/pvwatts.php) says our 3kW (really 3.12 kW because we got twelve 260W panels) should generate 4,363 kWhs in an average year. This is worth $663.17 per year on average.
Our system cost $12,175. Federal tax credit drops that by 30%. We also got a $500 Visa gift card for giving them two referrals and signing the contract within 2 days (they used it as a high pressure salesman technique: "if you don't sign in the next two days, you wont get the $500!!!"). One of our referrals also decided to get a system which gave us another $300 gift card. So total out of pocket for us is $7722. We did $1000 down and then they let us finance the rest at 2.99%
For numbers people:
Costs:
$12,175 - 30% tax credit= $8522 - $800 referral bonus = $7722 total out of pocket costs
$6722 is financed at 2.99% so $201 in interest the first year.
Benefits:
4363 kWh/year * $0.02 production incentive (good for 10 years) = $87.26/year
4363 kWh/year * $0.132 cost of electricity but this goes up every year = $575.92/year ($480 if we didn't pay extra for wind power)
total = $663/year
663-201/7722 =
~6% return on investment that will go up as electricity gets more expensive and as I pay less in interest each year
But really if you think of it as a leveraged investment, I only put $1000 down, and I'm still going to get $462 in benefits this year and every year, so its really a
46.2% return on investment. i.e unbelievably good!