2014 Solar Report

Solar 2014

We just finished our first full calendar year (i.e., January to December) with our solar PV system and it was a great one. Renovus (our solar installer) gave an amazingly spot-on estimate: they (well, their software) figured our 12-panel, 3.92 kW system would produce 4494 kWh per year. As you can see we got 4434 kWh this year. Less than 2% off.

I had some perceptions that didn’t meet up with reality. For example, I felt this summer was unusually mild and much less rainy than 2013. It also seemed like we enjoyed a warmer and sunnier September too. The data doesn’t bear that out. August 2013 was the first full month the solar system was in operation, so comparing from that point onward you can see that 2013 outperformed 2014 in every month except December.

2013 2014
August 523.53 513.01
September 478.46 472.33
October 319.27 303.06
November 244.93 198.84
December 66.72 88.08

I’m pretty happy that 90% of our electricity needs are met by solar, but I obviously want to do better. We have 300 watts of kitchen recessed lighting that gets used a lot (at least 2 hours a day; likely more) and still hasn’t been switched over to LED. I have a bunch of vampire devices like the Playstation 3 and Wii that don’t get used much but waste energy nonetheless. There’s more we can do to keep moisture out of the basement which would allow the dehumidifier to run less often. I’d love to get to 95% in the next year.

I can’t neglect to mention that we may have increased our usage by having central air conditioning installed this past spring (also by Renovus; they recently added HVAC to their list of services). I still need to write about that. Before that we relied on several window units. I haven’t done any work to compare the electrical load of central air against 3 window units, but according to our NYSEG bill there’s no doubt we used more electricity:

Billing Period Average Daily Use Average Daily Temp
July 2013 7 kWh 73° F
July 2014 7 kWh 69° F
August 2013 9 kWh 65° F
August 2014 14 kWh 65° F

So despite a warmer July in 2013, we used the same amount of electricity in 2014. And despite the same average temperature in August, we used 50% more electricity this year, though this comparison doesn’t quite work since in 2013 we were away for 10 days that month. Still, it’s probably safe to say we’re paying for that extra comfort.

Level

I still have a decent amount of painting (trim and bathrooms) to do before the housewarming party we’ve scheduled for the end of the month. The date was set in part to force me to get shit done sooner, but it’s still slow going. Nevertheless, I took a break from that to hang some art. This was in part to make the place feel a little homier, but also to declutter the house a bit, since there’s still random stuff (like artwork) lying around.

We have no design sense, so thanks to the miracles of modern technology we were able to get a friend in California to help us place one of the more meaningful pieces of art we own: four boards of mother-of-pearl lacquerware. There’s a big empty wall in the dining room and she said large art pieces work well in that kind of space. So I set to work measuring out and drilling four evenly-spaced holes across that wall.

Soulver on iPhone was great for this, by the way. It’s an innovative calculator that let’s you write out your problems, with results updated as you type.

Soulver on iPhone

In line with the common advice to “measure twice and cut once” I checked my calculations at least twice and measured each mounting point three times. I was using Ook screw hooks and each spot I was going to drill had a dot on it. I made sure to measure the dot’s height relative to the floor and the ceiling. Everything seemed great until I actually hung the boards.

As the photos below show, I was maybe 1/16th of an inch off (these are measured from the floor).

Hanging Lacquer Art 1

Hanging Lacquer Art 2

But relative to each other, the difference was huge.

Hanging Lacquer Art 3

How was this possible? Like I said, I measured from top and bottom to make sure it was level all the way across. Unfortunately I didn’t consider that the whole front of the house had shifted downward (or was built that way; who knows), which meant that while the ceiling and floor were still parallel with one another, that part of the wall was a tiny bit lower than the part just a foot and half to the left. Crazy.

Anyway, another hole later I got things lined up.

Hanging Lacquer Art 4

I relied too much on math, as I’m prone to do, and didn’t think to connect the four dots to make sure they were in a straight line. Lesson learned.

Also, I’m sorry the photo doesn’t show the art in the context of the room, but it’s still a bit of a mess and not something we want to show just yet.

Solar Monitoring Downtime

sunpower_down

In my last post I discussed one of the dangers of cloud resources: if the company goes under, so does your access to their data. But even when the company is alive and well you have to suffer with their infrastructure deficiencies.

SunPower monitoring has been unavailable for over 18 hours now. When their servers are down, the system at home can’t upload its data and I don’t know how much history it can cache. Hopefully when the servers are back up I will have not lost any information. The only way to see production data now is to use the LCD on the inverter (I could set up a webcam pointed right at it!). Consumption data can’t be viewed locally at all.

My preference would be for the monitoring equipment to run its own server. You could view the data on your LAN even when your internet connection is down, and with an open port you could monitor your system remotely too. I’d also be OK with some kind of hybrid solution, where the data is viewable locally but is also uploaded to SunPower’s servers. There’s probably no chance we’ll get anything like this.

Even when their equipment is up and running the website and app are intolerably slow. HD video is faster to load. I’d be happy if they just took this downtime to improve their servers’ performance or increase the bandwidth on their connection. I’m not too hopeful on either of those.

Solar Sign-off

This morning someone from the city came over to inspect the electrical work that Kenny Broadwell and his team did in preparation for the solar system installation. Since they arranged the inspection, Dakota and Keith from Renovus Energy took the opportunity to stop by and give us a final walkthrough of the solar system.

Dakota congratulates me for our system generating over 20 kWh yesterday
Dakota congratulates me for our system generating over 20 kWh yesterday

They presented us with a binder full of information: all the documents I signed, schematics of our system, the spec sheets and promotional materials for all the equipment, warranty information, and the manual for our inverter. Dakota pointed out that besides providing a record of all the work done, the binder is great for showing off the system to friends and family.

The cover features a photo of the system from the roof, much closer than I'll ever get to them.
The cover features a photo of the system from the roof, much closer than I’ll ever get to them.
Schematic of the system
Schematic of the system

Dakota then walked us through all the information displayed on the inverter’s small LCD. I had already browsed through the manual online to learn the meaning of most of the data displayed, but some things, like the individual power output of the two arrays (two arrays of six panels each) was new to me. He noted, for example, that a big discrepancy in output between the two panels might indicate a problem with one of the panels. He went over a couple scenarios in which we might need to power cycle the inverter or monitoring system to resolve small issues. He noted too that the inverter’s measurements could be ±5 kWh from the actual while the mechanical meter could be around ±3 kWh (if I’m remembering that right).

Of course, we don’t expect to spend much time in the basement looking at the equipment given that the monitoring equipment lets us check most of that data in easier-to-read, prettier output on the SunPower website or via their iOS app. We briefly discussed my fear that SunPower will go out of business and make our monitoring data inaccessible (since all data is uploaded to their servers before being made available to clients). There’s not much we can do in that scenario besides a.) reverse engineer the protocol to build our own replacement server, b.) replace the monitoring equipment with a third party option, or c.) understand that remote monitoring is a luxury we can do without. I get “c” pretty well, but damn I love looking at the data. More on monitoring in a future post.

So… that’s pretty much it. Apparently the city inspector has some things to go over with the electrician and NYSEG still has to put in a new meter to enable net metering. But since we’re already generating power and feeding electricity into the grid, most of that stuff is gravy.

Exterior Painting Begins

On June 28, the same day we had our energy audit, Perfect Painters started scraping away old paint to prep for exterior painting. In the two weeks since then they’ve also sanded, primed, replaced siding, replaced rotted trim, and completed most of the painting. In all that time I haven’t had much time to give any updates. Even worse, I’ve got big gaps in photo-documenting some of the work, like the progression of shake shingle siding being replaced (a wall of unfinished wood looked pretty nice).

I suppose something’s better than nothing. Since I’m so far behind, I’m going to do this with a photo gallery. This ain’t pretty, so just click on the first image to start.