The new paradigm in photovoltaics: on a roll, on lots of roofs

It's still generally more expensive to set up a solar photovoltaic power system that to simply hook up the grid, but times are changing.

One of the clearest cases for solar is away from the grid. You only have to be a few telephone poles away from existing powerlines before it's cheaper to install solar panels and batteries than to install the poles and powerlines.

But in recent years, even in town, solar photovoltaic systems are ending up on lots of commercial roofs.

It's possible through a Frankensteinian (some would say Frankenstinian) series of arrangements, which include state tax breaks, federal tax breaks, in some cases the transferability of those tax breaks (you may not have enough profit to take advantage of the tax shelters, but perhaps your bank or other institution does, and will do so), depreciation, and something called net metering.

Net metering lets you hook your solar system to the power grid, letting you feed power to the grid when the sun shines, and pull power from the grid when it doesn't. It means you don't need a big battery bank to store power for when the sun don't shine.

The amount you produce is subtracted from the amount you use.

In action, a deal like this can work this way: Your bank or some other firm owns the system on your roof. You pay the loan for the system, and your power bills go down—often they go down more than the cost of the loan. So not only do the solar systems break even, they can generate cash for you.

The other benefit is that as oil prices go up and power costs go up, your cost of power remains stable—it's the mortgage on your solar array.

Kaua'i County recently agreed to a 20-year arrangement with SunEdison LLC for a 72-kilowatt system on the roof o the county's Pi'ikoi Building.

In a press release, the county said the system should produce savings of $18,000 a year in the first year. It will also reduce the county's contribution to greehouse gas emissions.

See SunEdison's website at www.sunedison.com.

A number of Hawai'i-based solar firms provide similar service. ProVision Technologies, affiliated with Hawaiian Electric, does it: www.provisiontechnologies.com. There's a list of other providers at www.solarpowerdirectory.com/city/Hawaii.html, but it's not complete, and there are several other electrical contractors and solar firms around the state that either provide the service directly or have arrangements with banks or other organizations to handle the financing end.
© 2007 Jan W. TenBruggencate