Russell's Blog

The contractors installed the last row of panels this morning and switched on our solar array. Our house now produces about 15% more electricity than it uses!

The array produces between one and three kilowatt-hours for every hour of sunlight, so for today's half-day of production, we've generated 13 kwh.

Here's the read-out on the inverter :

Sadly, I don't have a way of getting the data out of the inverter yet. Once I add the RS-232 module, I'll have have more interesting things to say about our system. I'll post some pictures of the array itself once we've passed inspection.

The Sunny Boy inverter has an interesting user interface. There aren't any buttons -- you interact with the display by knocking on the front panel with your knuckle.

Our contractor, EE Solar, is about halfway finished with the solar installation at our house. Here is what they are installing :

• 14 SunPower 230 watt panels
• One SMA Sunny Boy 3000 inverter
• A second digital utility meter
• AC and DC disconnects with lockout-tagout switches.

The 14 panels will be arranged into two arrays with south-facing exposures producing 3220 watts of DC power. The inverter is about 95% efficient, so the nameplate capacity will be 2854 watts. The USGS indicates that we should get about seven to eight hours of usable sunlight per day on average. The array should produce an average of 17 to 20 kilowatt hours a day. This should easily cancel out our usage, and maybe a little beyond. I'm hoping for slightly better production, since Pasadena is higher and dryer than most of the LA basin.

Here is the equipment after delivery and upacking :

We were supposed to get a Sunny Beam monitoring station, but evidently there are some issues with buggy firmware, so they won't be available until September (more about that later).

So far, roof has been preped, the mounting rails are installed, the conduits are bolted in place, the DC wires are pulled, and the inverter has been bolted down. All that's left is to hang the panels, do the AC wiring, and get the inspection.

The installer crew was supposed to finish that on Friday, but evidently they decided to take the day off. The project manager at EE Solar pitched a fit. Nick, the crew boss, called on Friday to say he was really sorry. I told him that his schedule is his business, but if he can't come when he promised, he ought to let us know. On Moday, I'll ask him to run some extra conduit for ethernet to make amends.

Just in case you didn't have enough reasons to hate smog, researchers at UCLA's David Geffen School of Medicine have announced the results of a study concluding that exposure to diesel and coal exhaust causes heart disease. Many people live for years with elevated cholesterol without developing heart disease, and many people live with smog without developing heart disease. However, it appears that the combination of elevated cholesterol and exposure to fine particles from hydrocarbon combustion activate the genes that lead to the hardening of arteries.

So, if you live in the city, then you really need to listen to your doctor if she tells you to lower your LDL/HDL levels.

Anyway, I suppose PG&E is moving in the right direction by building the world's largest solar plant in Southern California -- a 6000 acre, half-gigawatt solar thermal plant in the Mojave desert. PG&E has contracted Solel, and Israeli company specializing in solar energy, to build the plant. There are already nine solar thermal plants operating in the Mojave desert, totaling 354 megawatts in capacity. When the new plant comes online, Mojave will have nearly a gigawatt of solar thermal generating capacity.

According to LADWP, the city's peak demand is 5.7 gigawatts, and a little more than half of that demand, or about 2.97 gigawatts, is met by burning coal. Assuming LADWP substitutes the new solar thermal capacity for coal capacity, LADWP could reduce its utilization of coal generating capacity, and thus emissions from coal, by about 18%. That's a significant chunk, but not nearly good enough.