This Littleton, Colo. house will soon have a home solar system powering close to 100 percent of its annual electric use. [Photo Courtesy of Pete Dignan]

Pete Dignan, a homeowner going solar in Littleton, Colo. writes about his experience in the second of three installments in this guest column for SolarChargedDriving.Com.
-->Link to Part I
-->Link to Part 2If you read the first installment in this series, you know that we were eagerly awaiting proposals from the three solar installation companies we had contacted.

Namaste Solar proposed a 6.075 kW system with a central inverter. The installed price was about $2.50 per watt after utility rebate and tax credit, which seemed consistent with market data I had found online. But the system would only produce an estimated 8,364 kWh of electricity – just 77 percent of our consumption last year. Namaste believed we didn’t have enough south-facing, unshaded roof space to install more capacity. One other concern arose; due to their phenomenal success, Namaste had a backlog of installations. Our rep estimated it would be six months before Namaste could put panels on our roof and connect the system to the grid. I was really eager to get this project moving, so the six-month delay was a real concern.

REC Solar came in with a slightly larger system: 6.45 KW, with an estimated 8,801 kWh of annual production. Better, but still not up to the 10,814 kWh we were hoping for. Their per-watt pricing was almost identical to Namaste’s, but with an extra: they proposed Tigo module maximizers and web-based monitoring as part of their package. But the most interesting part of the REC Solar proposal was the inclusion of a second option: solar leasing, through their partner SunRun. We weren’t planning to lease, but the SunRun option was interesting: no money down (without Tigo) or $1000 down payment (with Tigo), and a flat monthly payment for 20 years for all the power the system would produce. And the solar lease includes terms to make it fairly simple to exit the contract if you sell your home, either by transferring the agreement to the new owner, or buying out the remaining lease payments and adding that cost to your selling price.

Bella Energy proposed two configurations. The first included a central inverter and was the largest system yet at 7.72 kW, producing an estimated 10,587 kWh of electricity each year. This configuration came in at the lowest price among the three companies: about $1.80 per watt installed, including monitoring, after all rebates and credits. The second option was based on Enphase microinverters (more on these in the first installment), using fewer panels but offering the same estimated annual production. The cost for the microinverter-based system, including monitoring, was about $2.05 per watt installed – still very reasonable.

Time to make a decision. Since offsetting all or most of our electric consumption was a key goal of the project, the Bella proposals were attractive. I liked Bella’s pricing, and their forwarding thinking regarding microinverters, which help to optimize power production. I also liked our Bella representative - Alison was responsive, low-pressure, and highly informative.

Solar lease appealing
But the solar lease concept was highly appealing too. If we could have solar with zero (or nearly zero) expense up front, why not go that route? So we decided to ask Bella whether they had a solar leasing option. We quickly learned that they were just beginning to work with Sungevity, a solar leasing company based in Oakland, Calif. Sungevity does their own designs and provides equipment for local partners like Bella Energy to install and maintain.

The first proposal from Sungevity wasn’t exactly what we were looking for, but they listened and responded with a 7.4 kW, 10,312 kWh system with Tigo module maximizers and monitoring. We signed their agreement.

Our monthly payments in the first year will be $55.97, rising 2.5 percent per year until they hit $89.48 in the 20^th (final) year. Maintenance and insurance on the system is included. The lease includes a performance guarantee that provides for an effective cost per kilowatt hour (kW) of $0.07 initially, increasing 2.5 percent per year. Over the 20-year life of the system, we expect to save more than $24,000 over the cost for electricity we would have paid without going solar, beginning with about $400 savings in the first year. An additional benefit: our solar installation is expected to prevent the release of over 310,000 tons of CO2 in its lifetime.

But we’re not done. We still need the approval of our homeowner's association, and we have to go through the final design and installation, which will be complete by the end of October 2010 -- if all goes according to plan.

First installment: Proposal details, financing options, making our decision.

Final installment [Coming Soon!]: HOA approval, installation, lessons learned.

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