AEE Solar's David Katz
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Veteran solar pro David Katz, CEO of AEE Solar, has been in the industry since 1979 when he founded Alternative Energy Engineering to bring “power to the people” in northern California. He responded in 1981 to clamors from interested buyers with a “Lindberg ransom note” style cut-and-pasted catalog, becoming one of the first US solar distributors. The 2008 full color version of the wholesale catalogue is 208 pages and used by PV system designers and installers throughout the industry. An electrical engineer by training, David’s interest in solar began with a personal need for electricity in his owner-built Humboldt County home. Over the last three decades, David has built up one of the most respected and rapidly growing networks of dealers in the US.
—Joe Schwartz, SolarPro Publisher and Editor, caught up with David at ASES Solar 2008 in San Diego.
JS: What is the current split in your product sales between grid-tie and off-grid, and between commercial and residential installs?
DK: Probably 30% of our business is still off-grid. A lot of distributors have moved away from it. There is so much money in grid-tie, they are not interested. Commercial has got to be bigger now because, of course, the projects are so big. So I’m guessing it is close to 50-50 now, maybe even a little more commercial. And that is driven by the investment tax credit that’s maybe going away and thus everyone’s rush to install a PV system while they get 30% back from the federal government.
JS: What do you think the impact of that tax credit expiring might be?
DK: If it goes away, I think it will come right back. I’m just looking at these European and Japanese companies that are buying businesses in the US, for way more than they are worth, because they are assuming the market is going to grow like crazy. They see what happened in Germany, and everyone is looking for the same thing to happen in the US. I think those guys can’t be wrong. The market is not going anywhere without the tax credit. So I think they will make it happen.
JS: Do you think there are dark days ahead for small design and installation outfits?
DK: I think that there will be increasing rebates all over the country for residential systems. I am confident that the whole country is going to come along, and there will be lots of room for the small installers. People want to be green. People want to minimize their impact on the earth, but they’re still into running their air conditioning.
JS: What changes have you seen since ’81 in the profile of your dealers? Has there been a significant shift toward more mainstream electricians?
DK: In the old days, it was kind of the back-to-the-land continued person who was innovative and working his neighborhood as an installer. Now we see a lot of building, electrical, heating/air conditioning and home improvement contractors who are professionals in dealing with homes coming into at least the grid-tie side of it. The off-grid side is still populated by the old-timers who have been doing it for a long time. You can’t find a nuclear engineer under 50. I think that it is the same with off-grid guys.
JS: Speaking of batteries, I hear you’re running an ac-coupled system at your home in Arcata.
DK: We have an ac-coupled system where the PV array feeds the subpanel that has my critical loads in it: the refrigerator, the electric igniter in the fireplace and all the lights in the living room. I have an OutBack GVFX3524 inverter that has the inputs connected to a breaker in the main panel, and the output is connected to the subpanel. When the grid goes down, the subpanel sees the output of the OutBack. It looks like the grid is still there so the array keeps on working. I have a 4 kW array on the roof. I use two 1800-watt SunnyBoys, because they have 120 V output. I fed them into the 120 V subpanel to run my critical loads. I set it up fairly simply to have good grid-tie efficiency and standby power.
JS: What is the control approach?
DK: I just have a relay that is connected to the ac input to the SunnyBoy inverters and is also connected to the auxiliary output of the OutBack inverter. It measures battery voltage. There is no other control for it. As long as the SunnyBoy sees ac on its input, it will charge the batteries via the OutBack inverter if I am not using the power in the house. If the sealed batteries get up to 28.4 volts, this opens the relay. The array on the roof sees this as a power failure and it turns off. When the battery voltage drops a volt, the array turns back on again. So I use the relay as the charge controller.