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Issue #204 July 2007
Keeping the Lights On: Reality Time
by Steve Ciarcia
OK, I admit it. I’m a tech junkie, and it’s been a few years since I was focused on a large project. The truth is that every once in a while I need the excitement of ripping the place apart and building something entirely new.
It’s only been a few days since I decided to do this, but if it can be installed at my location (without clear-cutting half the county), I’m going to install a photovoltaic power-generating system. From what I can tell so far, installation costs border on the insane, but the fact that it satisfies my major objective for an independent, secure source of power, it may trump all the mitigating factors. Besides, at $0.20 per kWh in CT right now, I love the idea of selling electricity back to the power company.
I hatched that idea a few months ago when I was 1,000 miles away on vacation. Now that I’m back in CT and have had an opportunity to put my money where my mouth is, I thought I’d give you a status report.
First of all, I need to set the record straight. I’m not a tree-hugger, and I don’t believe that either extreme in the environmental debate has the facts straight. I suspect the answers lie considerably more toward the middle, where few dare to reside these days. What I do put my faith in is good engineering. I’ve been watching PV technology for many years while it seemed the exclusive province of the off-grid crowd and social isolationists. Now that PV and other renewable energy systems are becoming more mainstream and with fewer esoteric anomalies, photovoltaic power is starting to make real engineering sense for me (let’s hold the dollars and sense [sic] question ’til later).
Without checking the details of the specific program in CT, my first thought was to simply enhance my existing self-sufficiency by slapping a few PV panels on the roof and generating my own power. The reality of life is that while the architecture of an off-grid battery-backed PV system could accomplish this, the Connecticut Clean Energy Fund doesn’t provide rebates toward such a configuration, and it would be a lot more expensive going it alone. I guess my 14-kW diesel generator gets to stay as my main electrical backup for a few more years.
The aim of the CT rebate program is to take some of the load off the present electrical grid instead of simply adding another power plant. The objective is to replace some of the demand with personal renewable energy-generating systems, such as PV. The subsidy here is only for a professionally installed grid-tied PV system where you and the utility share the electricity you produce. Contrary to what I said before (call it media brainwashing), your electric meter doesn’t necessarily rotate forward or backward. That really only pertains to older analog electric meters, which, at least in CT, are always digital for grid-tied PV. The two digital readings represent what you use and what you produce. Simple subtraction decides who gets the money.
While I suppose I should be upset that I’m not going to be crawling across a hot roof in July, not personally digging 7’ deep mounting holes, and not lugging 33-lb solar panels up a ladder, there will be lots to document and interfaces to be designed as the installation progresses. The CT rebate program dictates the PV architecture and the approved list of installers. I did the math and I can’t even buy the raw materials to do this project for less than what a completely installed system ends up costing with the current CT rebate program. The only choice was to decide how big a system I could afford (no, the magazine isn’t paying for this), how much of the county to clear-cut, and who would be the lucky installer to get to deal with me while this mess is being built.
Incidentally, I’ve always been one of the first to adopt new technology, but this may be setting a new standard even for me. According to the CT Energy Fund, the total number of present residential PV installations in the whole state of Connecticut, population 3.5 million, is 152 (plus 18 commercial installations)! There are another 90 or so residential projects on the books for this year, but any way you look at it, we are definitely at the leading edge of the curve.
Presuming that everything stays on schedule, in a few months, I’ll present a couple of articles on how my system was built and add our house to the installed PV list. In case you are interested, my objectives haven’t changed in the last few months—only the complexity has changed. The contract has been signed and the rebate documentation has been submitted. If nothing clogs up the works or screws up the rebate, in a few weeks, there should be a bunch of people doing the ladder and roof trick at my house. The contracted system consists of 52 solar panels with a total rating of 10,760 W feeding three inverters. As expected with any project I start these days, it is also far more complex than originally anticipated. It turns out that to get this much capacity, my system will have to have panels on the roof along with two pole-mounted arrays. There better not be any glitches either. A crew of five has been out cutting and removing trees for the last four days. I can hardly hear myself think over all the chainsaw noise. That, and all this blinding sun I’ve never seen before!
I am putting my money where my mouth is because I believe we are at a point where PV and other renewable-energy systems are starting to make sense. Whether it be a solar heating pump controller, a smart load for a wind turbine, or a net-tied renewable energy monitoring system, etc., etc., I invite other authors to join me in creating regular coverage of this technology in Circuit Cellar. It’s one thing to simply add it to the interest list in our author’s guide. It’s quite another when you see us actively pursuing the technology and doing it ourselves. I realize that we are on the cutting edge of some very expensive stuff here and it will take time to evolve as a focus, but just like Circuit Cellar provides the premiere source of intensive, exploratory articles about the hardware and software methods for embedded control, it is my intention that we do it just as well for renewable-energy electronics. I invite you to join me.
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