4 Things To Think About Before Installing Solar Panels
By Kerry Cooper
We just joined the energy revolution – installing solar on our home in Healdsburg, CA. A new rooftop solar system is being installed every 4 minutes in 2013. With the fall of the cost of panels, solar is now affordable and worth a second look. Prices of solar modules have declined by 99% since 1976 and by about 80% since 2008 according to Bloomberg New Energy Finance. A federal tax credit of 30% of the system’s cost also significantly helps offset the purchase price. (That credit doesn’t expire until Dec. 31, 2016.)
There were 4 steps in our solar journey: education, buy vs. lease, selecting the contractor and installation.
We didn’t know much about solar. At all. Hopefully our time will shorten yours, although some is required as it’s location specific.
We spent time with one contractor who took our address and our electricity bills for the last 12 months. With that information, he showed us the detailed satellite image, where the panels would go, gave us many options on how to finance it. All were lease options, so we spent more time with others to make sure we could learn about the financing as well as options on installation.
With the others that we met with, we learned there are a lot of choices in solar in sizing and locating your system:
Location and design
Where’s the most room, best sun, etc. For our house, that meant a few options:
o We have a pool that is heated by solar. We could move those panels to the less sunny side of the house because the water heating is less sensitive to sun than the PV is.
o Cut a tree down that is by our front yard to make more space for the panels
o One contractor came up with a novel idea of putting it over our old horse-shelter/gazebo (all the way on the left on the drawing below)
The size of the system depends on how much electricity you use and how much you’re trying to replace. The estimates will use your rate plan, historic usage to project future use, and include calculations of net metering options to plan pricing and size. [47 states + DC offer net metering – selling your power back to the grid.] One thing to consider is that net metering places most solar customers in the lowest tier.
There are different specs for both the panels and the inverter. We spent some time learning about them to make sure we felt comfortable that the warranties and expected life would stand. Solar systems have both roof panels and an inverter. Both components should be covered by warranties – 20 to 25 years for the panels and 10 years for the inverter. A good panel should lose only a half a percent of conversion efficiency each year, meaning panels should last at least 30 years.
We use ~10,600 kWh per year, averaging ~850 kWh per month – but that average has large variations. During the summer and fall when we are irrigating, using A/C, and using the pool, our consumption grows dramatically. We jump from ~700 kWh/mo during the winter and spring up to ~1,100 kWh/mo during the summer and fall.
PG&E prices in tiers. The first tier is at 13c/kWh, second at 15 c/kWh and third at 31 c/kWh and for the summer, 40% of our usage is at tier 4, 35 c/kWh. [And there are several key days in the summer where we are charged 94 c/kWh for part of the day!]
In the summer when we use much more electricity, a greater % of our electricity is at the higher tiers so our weighted cost is much higher in the summer/fall.
Another way of looking at the cost based on the PG&E tiering:
When considering installing solar panels, pay attention to the location and design of the system, the electricity demand, the equipment and warranties, and finally, the utility pricing. Tune in next week for part two- Leasing vs. Buying!