PV Five Years In

The trigger for this post is the my solar vendor, SGE, offered me a $25 Amazon gift carfdto post a review to their Facebook page. So this is a sponsored post, so take everything with a grain of salt!

We've had our PV system for more than 5 years now and it's been great. Not a single problem with the system itself.

As for our electric bill, it's been an ever-growing negative balance. And that even adding all the driving that I do in my Nissan LEAF (all electric). Whether this continues is an open question as we've added two new electric consumers to the load: some mini-split AC/heating units in three rooms, and a new Chrysler Pacifica plug-in hybrid mini-van. These should combine to eat up a good deal of the excess generation, if not all of it.

I should mention that all-electric cars are a joy to drive: very fast and very quiet. And much less maintenance than gas-o-mobiles. I've been very amused a couple of times recently to get third-party solicitations to extend the warranty on my LEAF. They list a hypothetical invoice for repairs that include things like water and oil pumps for thousands of dollars. Well, folks, the LEAF don't have those, so your marketing is just funny, not convincing.

Beyond the electric bill, we've been receiving quarterly bonus checks from the SRECs generated by the system. These have added up to over $13K over the life of the system to date. Not too shabby, and it always feels like found money.

So color me a big supporter of personal solar PV. If we were doing it today, I think the price of the system would be significantly lower, as panels have come down in price. Even though the government support is waning, the economics still make sense, and the good feeling of zero-CO2 energy is very rewarding.

37 Fletcher Solar PV Installation

After a good deal of research we decided this year to go ahead and put in Solar Photovoltaics on our roof here in Bedford. This blog describes what we did.

First, I want to thank my colleague, Christopher Mirabile, who did this over a year ago on his house, wrote the process up in detail on his blog, and also helped me understand a lot of the intricacies of the process.

Second, thanks also to EnergySage.com and their CEO, Vikram Aggarwal. I used their system to bid the project out competitively, and actually found my contractor through EnergySage.

Finally, thanks to Dave Simmer, the sales guy for Second Generation Energy, who got the contract largely because his knowledge of the industry and his attention to our needs put him above the rest of the contractors I talked to.

I should mention at this point that all three contractors with whom I spoke at any length were highly committed to renewable energy and exactly the kind of people one expects to find in this industry - intelligent and personable.

As of this writing the system is completed but awaits two final steps before going live. First the Mass Clean Energy Center (CEC) needs to bless some paperwork that authorizes various rebates and benefits. After that, NStar needs to replace our existing meter with one that can do "net metering". The existing meter would treat any electricity our roof generates and pumps into the grid like power we're using, so we'd actually get charged for it. With a net meter, if we pump power into the grid (as we will on sunny days) the meter "runs backward" and we can actually end up with the power company owing us money! Sadly one can't cash out such an excess, so it's best to stay just below that threshold.

Once the system is turned on (a few weeks from now, most likely), I'll post again to say how it went.

Nissan Leaf

One of the things that Dave Simmer got us to think about in sizing our system was what kind of car we might get sometime. He pointed out that as owners of two elderly Prius hybrids, our next car would very likely be a plug-in of some sort, and hence sizing the system beyond our current usage (pun intended) made a lot of sense. Not only would we charge our next car for free, but we'd also be generating more SRECs in the process. Sounded good, and that's what we did.

I had visited an old friend of mine in Palo Alto and had admired his new Nissan Leaf. I looked into those here and found that they are very pleasant to drive, and make a great commuter car.

Given that both of the Priuses were around 90K miles old, it seemed like a good time to sell one of them. In fact we were able to do so on Craigslist in a day!

So we took delivery of the Leaf a couple of days later, and voila! Had to charge it on house current for the first couple of weeks until the 240v charge station got installed, but even that worked fine.

I stuffed my bike in the back and took the Leaf out to Lancaster, MA, where the internet had informed me there was a charging station behind the town hall. I found the charger there, as advertised, and plugged in before taking a nice ride down to Clinton and around Wachusett Reservoir. And apparently by law in Massachusetts public charging stations cannot charge you for the electricity they provide. How cool is that?

Here are shots of the charging station we installed in our garage, as well as a few of the Leaf.

Bike fits in the back, wheel on!

Public charging station in Lancaster.

Installation Photos - Panels

Rails in place

Panels going on

Panels - undersides

Ladder/lift for panels

Workers on the panels

All panels but one in place

The DC feed to the basement

Inside systems installation

Here are the two SunPower inverters that receive the DC feeds from four strings of panels on the roof.  

The inverters (now closed up) and the rest of the system. Clockwise from the top right, here's what happens.
Four strings of DC power from the roof panels enter the two inverters.
Each inverter feeds its AC output (240v) into the large junction box on the lower left (it has a 30A breaker on each feed).
The combined output feeds through a mechanical (!) meter into the main electrical panel.
In addition, a utility-grade electronic meter (above the mechanical meter) feeds back my power generation through the internet to SunPower, which in turn uses that information to generate my SRECs.
Finally, the box at the upper left contains whole house monitoring for the electrical system, so that we will be able to track usage from a web site. In that same box is a network switch that connects to my internet router.

This is the monitoring box with internet switch.

This is the main electrical panel. The big black wire entering the box at the lower right is the AC feed from the mechanical meter, and it goes to a 50A breaker. The fat gray cable coming in at the top right houses the feeds to the two monitoring systems.