Solar Monitoring

Solar Monitor ScreenshotWhile the Enphase Enlighten monitoring site is pretty swanky, it’s slow to load and extremely flash-heavy.  It has the advantage of being able to do per-panel monitoring, event log monitoring, etc, but I was hoping for something a little more lightweight.  Enter pachube.com.  Let’s build out the internet of things….

The Envoy system monitor for the Enphase inverters has very basic output monitoring abilities; it shows you current power, and daily, weekly, and lifetime energy production.  So, we can screen-scrape this and upload it to pachube, then do what we like with the data.

I have this script on a 5-minute* 10-minute cron job to get the data.  The Envoy doesn’t seem to update faster than 5 minutes, and it’s such a gutless wonder, doing it any more often than that brings it to its knees, and it stops updating the main site!  If you have problems, you may want to reduce the updates to 15m or more.

To use the script, first get a Pachube API key, and set  up a new Pachube feed.  Add 4 datastreams, for instantaneous power, daily production, weekly production, and lifetime production, in that order.  Edit the script to add your envoy hostname/IP, your API key, and your feed ID.  Then put the script on a 5-minute cron job.  You’ll start seeing the data on a Pachube feed page like this.  Then you can use some of the apps highlighted on apps.pachube.com to create widgets as in the image above, as seen on this page.  You can even get an iPhone app to monitor the data, or create an OSX dashboard widget from the HTML objects!

*Edit: Don’t set the cron job to be more frequent than 10 minutes.  I’ve had trouble with the Enovy unit bogging down and not reporting to Enlighten if you hit it more than every 10 minutes (!)

At last: Solar is running

solar-meters

I got the meters installed today.  It took about 2 minutes of work, after 2 weeks of wait.

The meter on the left is the “production” meter which measures how much power the panels have made over their lifetime, period.  It’s so the utility knows what they got for their rebate money.  (Oddly, it’s the exact same Centron C1SC meter I had previously, for usage measurements!)  The meter on the right is the net meter.  Today it’s running backwards, even though it’s cloudy, because the house is pretty much at base load.

All that’s left is the anti-islanding inspection*, but my installer tells me the utility is OK with having them on prior, so we’re up and running!  On a cloudy day, of course.

I don’t yet have the official Enlighten URL for the array, but my homebrew monitoring is here on pachube.com.

*And one concern about the physical install of the panels & cables, which might possibly require removal and re-fastening of the panels, which would just be awful at this point.

Edit: The official monitoring site is now active.

OPOWER!

So, Xcel Energy was sending out fliers from OPOWER on a trial basis, trying to make peer pressure work to convince people to reduce their energy usage by comparing them to neighbors in similar homes.  OPOWER claims fantastic results from this, by simply making people aware of their usage and how it compares to others.

Sadly, it seems that this approach does not work for many conservatives.

Anyway, both my brother-in-law and my neighbor got the flier; I did not.  My brother in law went so far as to “feel really bad about it” and then put it in the circular file.  My neighbor filed his away for “later.”  Failures?  I dunno.

Anyway, the interesting thing is that there was a URL on the flier I saw, for the Xcel/OPOWER site at http://xcelenergy.opower.com and it turns out that you don’t have to be randomly selected to be able to sign up for online access.  It’s not exactly the same information as was on the flier, but it’s still interesting.  And, you can even get daily usage over a week, which is something I’ve been wishing they’d provide since forever…. Aside from that, it’s the usual pap about “seal up household leaks” and “buy a programmable thermostat.”

Open-source power monitoring

I’ve been interested in doing power monitoring on the house for a while, the TED 5000 unit seems neat and the Brultech ECM1240 monitor also seems pretty good.  Both are around $200, but both have drawbacks.  The TED only monitors mains, and while the Brultech can monitor around 5 branch circuits, it lacks the simplicity of a built-in webserver like the TED.  Most of the software developed by the company, at least, is Windows- oriented.  But I’ve found some neat other projects that might be fun. Continue reading

Affordable WiFi Thermostat?

Update 11/20/2010: Finally, these things are available now and at Home Depot for $99!  The same thermostat under the Homewerks brand seems to be available at Amazon [amzn] for about the same price as Home Depot; take away tax and add free shipping and the price is comparable. See my other blog post on the subject.  Read on for the original post…

I’d been looking for a WiFi thermostat that was affordable for a while; most seem to be vaporware or very expensive – but the CT30 from the Radio Thermostat Company of America looks like it may just fit the bill.  Continue reading

I want daily electric meter readings!

Was talking to my energy company today about past usage (net result: I’m not doing as well as I’d hoped on the energy savings front; I’m sure the mythbox doesn’t help …) and they mentioned that they could see daily meter readings for my house.

I asked how this works, and the Centron meter on my house apparently sends a wireless signal to a box on the pole, and the power company reads it from there.  Well, that’s cool.

Why can’t I see it too?

I like the talk of the smart grid deployment, but here is data that is available today, but it’s just not available to people who can use it to make a difference in their energy use.  It’s a common phenomenon that measurement changes behavior; wearing a pedometer can lead to more walking, MPG displays can lead to better mileage (ok, cause/effect might be in question here).

But for myself, if my daily energy use were presented to me on a realtime basis, I think I’d do my best to keep pushing it down.  And it’s “just” a question of moving existing data to where customers can see it.

Hopeful, but frustrating at the same time.