In her 2009 book “Sleeping Naked is Green” Vanessa Farquharson highlights many of the ways in which simple changes can both conserve resources and serve as vehicles to increase awareness of what other changes can be made to support a greener existence.
A friend recently put a new roof on their house and opted to go with metal shingles. While helping research various options, one thought which came up several times was to try and make use of a new roof installation to add solar generation capability, and what appeared to be the easiest option was to use thin film photovoltaic on a standing seam roof. A basic feasibility study indicated that a standing seam roof would look very out of place on the house and that the location was not overly well suited to solar due to a substantial tree canopy over the house… so the idea went away.
A few weeks later while baking on the roof at Rurikia repairing a shingle which had lifted slightly during a storm, I realized that Rurikia was fairly well suited for the installation we had opted against for my friend’s house. Although a southern exposure would be ideal, the unshaded south-west exposure of Rurikia would still be useful, and a standing seam roof would fit in perfectly with the more rural surroundings. After a bit more research the decision was pretty much made that when it comes time for a new roof at Rurikia it will very likely be a standing seam metal roof.
That decision made, my thoughts turned to trying to integrate a solar array on the new roof. Although the thin film approach looked very promising initially, the more I looked at it the less enthralled I became due to questions about longevity and adhesion. I like the concept, but prefer the more proven record of standard photovoltaic particularly given that on a standing seam roof the mounting racks do not need to penetrate the roof.
That’s when I sat down with the numbers. Rurikia is supplied with electricity from a rural electric co-op, and their rate structure includes a $30 monthly connection fee. They do allow net metering and solar installations of up to 10 kW nameplate rating, but to do this there is an additional $5 connection fee charged. All told, there is a flat fee of $35 to have the house connected to the grid with a solar installation of any size, regardless of electrical usage.
So far so good, but having the capability to hook into the grid is useless without the equipment to do so. The first question is how big of a system to get. My average electrical usage across the past few years has been 270 kWh per month, and very conveniently there is a solar test installation rated at 3 kW a few miles away from Rurikia which has averaged 300 kWh per month over the same timeframe. Ignoring any differences in exposure, this indicates that a 3 kW system would pretty much come out around even in terms of offsetting my usage with a larger system able to generate excess.
Larger system size implies larger cost but also implies greater excess, so some optimization had to be done between the options. The first job was to obtain reasonable data for system costs, then look into what incentives are available to come up with an installed out of pocket cost. A very good source for this data is http://www.dsireusa.org/ There is a 30% federal tax credit available, but unlike many other states Indiana does not offer any state incentives aside from not taxing any increase in property value due to the installation (which probably has more to do with there not being a good way to determine the change in property value than any other factor). Oddly enough, there is a sales tax exemption for the mechanical components of wind power systems, but not for solar. There are a handful of local incentives, but none which would apply to Rurikia.
The attached chart summarizes the current status and shows that even going with a 9.5 kW system for the maximum it would require tripling my average monthly usage to 1000 kWh / month to break even on the system within the predicted 25 year lifespan – and ignoring any system maintenance costs. Staying at the current rate of usage and a 3 kW system pushes the breakeven point to 32 years. These rely fully on residential systems to be installed on emotional grounds as none of these make any economic sense, and until this is achieved residential solar installations in Indiana will continue to play a trivial role in the state’s power budget.
There can of course be a debate about the role of incentives and if governments should offer them, however state and local governments across Indiana already offer numerous incentives across the board and do have token energy incentives; for example there is an incentive for solar powered attic fans. More states in the US do offer solar generating incentives than do not, and it’s time that Indiana became one of them. Although not charted, adding a sales tax exemption and a 20% tax credit would bring even a 3 kW system’s breakeven point to around 22 years, which would put it in the range of many more people.