The Frank Fenner Building Solar Array: Production v. Consumption

Alright, let's kick this blog off shall we?  I mean, it's been 9 months since my last (and only) entry - what a slacker!  Well, at least I've been slacking off as a blogger, but not as an ultra cool, rad scientist researcher guy (**insert that emoticon here**).  No, I've been quite busy! And I have plenty to write about for you, trust me!  In fact, I've even recently been able to join up with a few fellow Fenner School residents to start highlighting the benefits of our super-snazzy new green home - The Frank Fenner Building.

 For those of you who are not aware, the Fenner School of Environment and Society, which I attend as a PhD student, is home to a whole host of amazing researchers who work on subjects related to policy, economics, social sciences, ecology, bushfires, forestry, climatology and a whole lot more!  Yep, there is even a rogue guy traipsing around pretending to know a thing or two about solar panels (yours truly).  

As a part of our committment to a healthier, greener, more earth friendly, ecologically minded world - we made our new home a super efficient, low waste, solar powered haven of natural light and loaded it up with energy sensors.  We officially opened the building in October 2011, and after a bit of settling in for the first few months - I believe we have now had a whole year of 'regular' usage and solar energy production, which I can now analyze. And guess what, that sounds like perfect subject matter for a blog post.  

So let's start off, talking about what I know best, solar power.  So just what does our new-fangled futuristic building have hidden on top of it's black-grated, wooden paneled facade?  Oh you know, just 142 panels of solar goodness.  Each producing 240W of power under abundant sunshine, making for a total rated power output of 34.08 kW.  It's made of high quality Bosch solar modules and has three 10kW Aurora PowerOne inverters.The panels are situated at four different azimuths, all within 11°of absolute north. I've even included a nifty little schematic and some photos for you to see it yourself:


So, yeah, I know what many of you may be thinking... what the heck does that even mean Mr. Solar Smarty Pants?  240 Whats?  34.08 Aurora Whos? 1.21 Gigawatts?  What's going on here?

Ok, ok, ok.  So even if you aren't sure what a 'Watt' is (a unit of power, a Joule/Sec), or what any of the other strange things I talked about are, you can certainly follow along with rest of this post. I promise to keep it basic.  

So the solar array on the rooftop of the Fenner building was designed to offset as much of the building's electricity usage as possible - thus the whole 'green building' thing.  But how much electricity does a whole building of super-ecology brained, research paper writing, tea drinking Aussies consume?  Let's start with a look at the past year (meaning the last 365 days).  Here is a plot of our collective electricity consumption, in terms of kilowatt-hours (kWh), which is the unit you see on your home electricity bill:


 So what can see?  Well first, that our consumption average consmption peaks in early winter (who's been running heaters ;-) ?)  And hits a minimum over the holiday season.  Another interesting piece of information is the weekly cycles that are spread througout the data.  Let's have some fun with that!  Now our red line is grey, blue dots are Saturdays and puple ones are Sundays!  


 So with the combined data from the 'Holiday Break' period, and the purple Sunday dots - which indicate the periods when more people are probably at home, and not working - we can now get the 'resting heartrate' so to speak of the building.  So, with no/very little users present, the buidling consumes around 85-100 kWh (a mean value for Sundays is 96.74 kWh).  That's equivalent to approximately the combined daily usage of four average households of four people in the Canberra region.  

Now, onto the burning question!  How much electricity does our solar array produce?  Well lucky you, I have a plot for you right here:


And once again, we certainly can see some interesting variations in the data.  The first thing that jumps out at all of us, is of course, the seasonal cycle.  Production is at a minimum in the winter, when the sun's altitude is the lowest, and at a max in the summer.

But what we also see is how incredibly varied the amount of power coming out of the solar array is!  We can see clear days and cloudy days, and how much a seriously cloudy day can ruin our solar power output!  The solar array can easily see 70% reductions in total electricity generated from a very cloudy day.  But the thing I know that everyone is peering into the graph trying to see is:  "How does production compare to consumption?".  Well, let me help you out, stop squinting and look at this plot instead:


See, I promised I would make this easy!  Just pay attention to the black line in the middle.  Everything below that line (zero) is red, and represents a day where the Fenner Building consumed more electricity than it produced.  Anything above the line, is green, and is a day where more electricity was produced than consumed.  From this plot, we can certainly see that the Fenner Building clearly more often produces less electricity than it uses, but where does it stand overall?  Glad you asked: 


So there were two months, December and January in which more electricity was produced than consumed (Holiday break anyone?).  October was left out, since there was a break in the solar data, and April 2013 is not a full month!  But, with all that being said, overall, the Fenner Building has provided just under 58% of its own electricity over the past year (April 2012 - April 2013).  Overall, that's not bad!  Well done solar panels :-D.

Oh, and for those of you who have been smart enough to read all the way to the end, here is a little present for you.  The live power output from the Solar Array on the Fenner Building can be viewed here.  And, just as a special treat, I'll host the live power output image here:



Well, that's all from me for now! It's late and I've got to get to bed and be haunted by dreams of my PhD code chasing me into an early grave... until next time!