March 22, 2010 | 7
Editor’s Note: Scientific American‘s George Musser will be chronicling his experiences installing solar panels in Solar at Home (formerly 60-Second Solar). Read his introduction here and see all posts here.
Who could put a price on spring? Ah, the reawakened life, the budding flowers, the dabbles of green in the grey wood. Well, actually, a solar enthusiast can put a price on spring. It shows up right on my electric bill or my real-time electronic display. On March 4th, my solar array passed the milestone of feeding more energy into the grid than we drew back from it. As the days rapidly lengthen and the sun climbs higher in the sky, a surplus is becoming the norm. For five of the past seven days, we have produced more than we’ve consumed. Solar energy has even reconciled me to that other rite of spring, tax time: I’ve gotten a nice big pile of money back from Uncle Sam to help pay for the solar array.
It has been a while since I’ve been able to update the blog; my day job (writing and editing articles for the magazine about astronomy and physics) has been all-consuming. But I couldn’t let the spring equilux and equinox go by without any words of celebration.
Like many early-adopters, I’m a little obsessive. I monitor my array’s performance with no fewer than four separate monitors. In addition to the inverter readout and utility meter, I have two other devices that measure both the panels’ output and our household electricity consumption. One is a Locus Energy monitor that our installer, 1st Light Energy, installed at its expense to make up for its mistakes. The other is the TED5000, which I paid for and wired in myself.
I had used the earlier TED1000 and found it somewhat disappointing. It interfered with our home automation system, causing lights to go on and off at random, which seriously eroded its popularity with my wife and daughter. They rebelled by willfully leaving every light in the house turned on. One day, the device completely bricked-up. Frankly, that came as a relief even to me.
The newer model is much more capable. It can monitor both consumption and production, has a data-rich web interface, works with third-party iPhone apps, and interfaces with Google Powermeter, an iGoogle widget that displays net energy use. But the TED5000, like its predecessor, interfered with the automation system. This time, I bit the bullet and, inspired by a post on the Powermeter forum, moved the monitor to its own circuit isolated by electric noise filters, which seems to have solved the problem and restored some of my domestic moral authority.
These monitors provide an engrossing look at your household life and let you drive a stake through hidden wattage vampires. Mine showed a 150-W load that came on or off at regular intervals, staying on about half the day in all, for a total of about 650 kW-hr per year. This matches the energy consumption of a fridge. An EnergyStar fridge would be at least 20 percent more efficient, but alas the payback time would be prohibitively long. So I bought a cheap fridge thermometer and found I was able to turn up the temperature somewhat.
The energy monitors also are morale-boosting reminder of you why you just shelled out $20k+ for those panels. You make it back, dime by dime. As David Kaltsas of SunWize, a large solar wholesale distributor and residential installer on the West Coast, says: "Essentially what you’re doing is buying 20 to 30 years of electricity at one time."
In an upcoming blog post, I’ll describe my conversations with Kaltsas and others in the solar industry about where they’re heading and how government regulation, especially at the local level, could be streamlined. In the meantime, I recommend reading Chris Kaiser’s Map-a-Watt blog. You might also enjoy the experiences of Debra Herman in Mill River, Mass., who has blogged and written about the grid-connected 4.8-kW solar array she installed a year ago. Her state and federal incentives went through smoothly; her only problem, she says, was that she had to cut down some trees because of shading. The array produced surplus power through November of last year. She, too, is looking forward to getting back into the black as springtime unfurls.
Web interface of Locus Energy monitor, courtesy of George Musser
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