34 kwh in six days

We generated more than 10.5 kwh on Sunday, which is charted above.  It's interesting to see that at least some power is generated over the course of 12 hours, even when the sun is very low, and on very rainy days, like Tuesday.

We generated 34 kwh in our first six days (below), running at a pace of 170 kwh per month; that seems to be in the right range, as PV Watts says I should generate 181 kwh in April (http://rredc.nrel.gov/solar/codes_algs/PVWATTS/version1/US/Maryland/Baltimore.html).  (I may have to double-check the inputs there).  

Power!

We're live!  Cheers to Pepco for checking out the system and replacing the meter in just a week after talking to me. 

Turned the system on last night and it was perfectly sunny for most of the day -- we generated 9.53kwh in total.  

The panels were generating as much as 1.5kw at around noon, and more than 1.4kwh average between 11 and 12, which is close to the built-in capacity of 1.61kw.  Sunpower provides a website with a cool chart showing hourly production and I'll try to figure out a way to get that up on this site.  It looks like we were producing power all the way from 7:00 am to after 6:00 pm.

Six more weeks?!

I just had a useful update conversation with the representative from Pepco, our utility here in suburban Maryland. The upshot is that it could be up to six weeks more before I can turn on the system.

Turns out, the solar installer only submitted the application to Pepco on March 23, several weeks after the installation. Pepco now has to review the details of my system and Pepco's readiness to handle it. That technical review, which she said is unlikely to uncover any hitches, can take up to three weeks.

After that, Pepco will have to schedule the net energy meter installation, which could take up to 30 days.

She assured me both processes are usually quicker than that, but at this point, all these wasted sunny days are getting me down. I'm starting to hope for rain! Okay, not really.

Approved but not live

The County folks were here to check all the wiring and conduits and gave their stamp of approval, in the form of an official-looking sticker on my electric panel and some signed forms.  But the system still ain't live.  The utility, Pepco, has to come and replace my meter with a net meter, so the electricity I produce will be recorded and deducted against my consumption.  It turns out the digital meter I have can only measure the total amount of power flowing through -- which means if I turned on the panels, the meter would tell Pepco to charge me for the energy I use, plus the energy I produce.  That's not how it works on my spreadsheet.  Not sure how many weeks I'll have to wait now...

Panel envy

I'm suffering a serious case of panel envy.  My college friend George just signed a contract to put 20 panels on his New Jersey home.  My roof, as you'll note in the photos down below, could only handle seven.  His blog is cooler too:  www.sciam.com/blog/60-second-science/post.cfm?id=early-steps-size-matters-when-youre-2009-02-26

Check out PBS Nightly Business Report

Our house was on PBS tonight, on the Nightly Business Report. No, the story is not about me -- it's about green jobs and the federal stimulus plan. Reporter Dana Bate interviewed Tony Clifford, president of Standard Solar, in our sunroom while her cameraman filmed the Standard Solar crew up on the roof. Check it out at www.nbr.com. It's part of the series, "Reviving the Economy," look for the segment on February 26 called "Getting Green from Green Jobs."

First 20 watts produced at sunset

We produced our first power yesterday, and it was a small but real thrill when Matt of Standard Solar plugged in the SunPower monitor at 5:30 and showed me the reading: 20 watts, just enough to keep one of the energy-efficient lightbulbs going. That's not much, but then the sun was setting behind the trees and not shining directly anywhere near the roof. I look forward to seeing what the system can do at the peak of the day. It's a 1.6 kilowatt system, so I imagine that is the target.

Frustratingly, after showing that it worked, Matt turned the system off. Now we have to wait a week until the utility company has come over to review the system and allowed it to go live.

Installation complete

Today we installed a 1.61kw solar panel system on our roof in suburban Maryland. It consists of seven SunPower panels on the roof on the left side of our house, facing almost directly south, tilted about 30 degrees, and with almost no interference from overhanging tree branches.

In short, it's an ideal spot for solar panels. The small system should produce 1.9 megawatt hours per year - 15% of our annual consumption, enough to cut our energy bill by $330.

It's been almost exactly three years since I caught the renewable energy bug, in early 2006, when a neighbor explained at a cocktail party that global warming is happening right now, and not over some centuries, as for some reason I still believed was the case. Within weeks of that conversation, after hours of Google-led self-discovery, I had replaced more than 30 lightbulbs in our 2,500-square-foot house, become a fanatic un-plugger, and set up an Excel file tracking our monthly kilowatt consumption back to 2004.

Also some time in 2006, I computed the cost and returns of investing in solar panels, and decided that the technology, the incentives, and my household finances were not quite ready. By my calculations at that time, a 2kw system would cost about $20,000, minus government incentives of maybe $4,000, resulting in an internal rate of return of less than 2%.

Three years later, while the technology and the household finances are not particularly different, the government incentives are dramatically better. The system will cost $15,990, but with Federal and County tax incentives and a State grant, we are hoping to pay less than $4,500. The annual savings will be about $330 on our electric bill, but due to another government program, we hope to earn an additional $700 or so in the first year by selling renewable energy credits, declining each year.

In all, the system should pay back its cost in six years.

I'd like to use this blog to document my family's solar adventure, hopefully making more transparent a simple technology that still seems exotic to most of us. I'll put up photos, regularly track our production against expectations, and let you know exactly when the government incentives pay off - and whether they pay off as expected. I'll try to note any technical hitches as well as any hidden costs that may come up. For example, I had to upgrade my electrical panel because the existing panel had no main disconnect, adding $1,500 to the bill. (Does replacing the 17-year-old shingles on the roof count as a hidden cost or something we would have done anyway? You decide.)

I'll also talk about our efforts to reduce our energy consumption, which of course is the cheapest and best way to reduce your carbon footprint. After the initial assault on consumption, I'm not glad to report that those kilowatt hours have been creeping back up.