Case Study: Blue Heron EcoHaus

Blue Heron EcoHaus
  • Location: South of Saskatoon, along the South Saskatchewan River
  • System size: 6200kW
  • Predicted system output: 9300 kWh/year (predicted by installation company)
  • Actual system output: 8189 kWh in year one
This case study is of of a ground mounted array located at the Blue Heron EcoHaus near the city of Saskatoon, Saskatchewan. Kent and his wife have been living in the areas since they moving there from the city of Saskatoon in 2014.
We interviewed Kent in March, 2017 and put together this case study along with information from his blog.

Why create the Blue Heron EcoHaus?

My wife and I moved from the Saskatoon to the country in 2014. Both of us had been born and raised in the city, so moving to a farm and beginning a rural life was a completely new experience for us. Our primary motivation was to live more simply and more sustainably then our city life had allowed. Building a highly energy efficient home with renewable resources fit as a necessity for our new life.

Why decide to install solar power?

In addition to wanting to use sustainable and renewable resources in our new home build, it also came down to cost, to some degree. Our property had already had power brought out to the site by the previous owners. There was however no natural gas. The cost of running a natural gas line to our property was in the range of $25,000. Can you believe that a lot of people would pay for that? Having a non-renewable resource piped to your home and then having to pay a monthly fee forever afterwards. I had no interest in this. Instead we used that money and invested it in solar panels. Something that pays for itself each month in the energy generated. In fact, we save money each month having them. It was a no-brainer to me.
 

What results did you see with solar?

For 2016, we tracked our overall energy use compared to energy generated. The average Saskatchewan home in 2011, uses 30,555 kWh (110 GJ according to Stats Canada). Our home used 19,000 kWh, not taking into account solar generation. The solar panels (6.2 KW PV array) generated 8189 kWh, lowering our overall consumption to 10,811 kWh, or approximately one-third the use of a standard home.

Overall satisfaction with solar system

We are very pleased with our choice with solar panels. I cannot understand why more people don’t go this way. The cost of PV has come down markedly and is at par, and soon will be below cost, when comparing the cost of solar panels added to your mortgage versus paying a monthly power bill. We are planning to add to our PV array to bring out energy use towards complete Net Zero.

Blue Heron EcoHaus Solar Power
Here is a picture of the 6.2kW ground-mounted array installed at the Blue Heron EcoHaus.

The Back Story

(you can also read this story on their blog)

We had spent a lot of time planning and designing a house that would be energy efficient, aesthetically pleasing, and cost effective. This is a fine balance to try to find. However, it really is a big guessing game until you actually live in the space and track it’s performance. You can run all of the computer programs you want, but you really don’t know how things will be until you’re in and living your normal life.

We had installed PV solar panels on the house to combat some of our energy use with the hope that someday we could work towards a Net Zero home, but this too, seemed to be a big guess as to how well it would perform.

In the planning and designing stages of the house we ran a couple different energy models on the house. The first is called the “HOT2000” program. “HOT2000 is an energy simulation and design tool for low-rise residential buildings.  This software is widely used across Canada to support program, policy and regulatory development and implementation.  HOT2000 is developed and managed by the Office of Energy Efficiency at Natural Resources Canada” (NRCAN). It was originally designed for use with the R2000 energy efficiency program, which was an early promoter of green home building in Canada.

We later used the Passive House Planning Package (PHPP), which is now the widely used software program for building highly efficient homes worldwide.

My intent with this article is to report the varying predictions of the these two programs, as well as our predicted solar generation, and also to show our actual energy use for the year of 2016 – our first full year in the new house. I’ll also report some considerations and possible options for the future.


1) Pre-Build Energy Modelling

I had been very curious about this when we were in the early stages of planning the house. Most of what I read was the predictions of various homes, but I’d only come across one house that actually tracked and reported its energy use – that being the Mill Creek Net Zero House in Edmonton, AB, Canada. Which, although using exceptionally little energy, did not meet it’s net zero target. That being said, it was very close.

I fully did not expect our home to be anywhere close to net zero, but we hoped that over the next number of years we could gradually build our solar panel array (as costs come down) to eventually reach our goal.

OK, let’s get to the numbers:

HOT2000 Predictions:

Annual Space Heating Energy Consumption: 7159 kWh

Annual Domestic Hot Water (DHW) Energy Consumption: 3409 kWh

Annual Appliance Energy Consumption: 8760 kWh

Total = 19,328 kWh/year

PHPP Predictions:

Annual Space Heating Energy Consumption: 7584 kWh

Annual DHW Energy Consumption: 3974 kWh

Annual Appliance Energy Consumption: 11,310 kWh

Total = 22,868 kWh/year

PV Array Predictions (6.2 KW)

PHPP Estimation: 7321 kWh/year

Solar Installer’s Estimation: 9300 kWh/year

So obviously there are discrepancies between the HOT2000 and the PHPP. Although their prediction of Heating and DHW are quite close, surprisingly the Appliance use was significantly different. Also, surprising was the discrepancy in the solar predictions – I was a bit disconcerted by the drastic difference of 2000 kWh/year!!

For comparison’s sake, according to Stats Canada website’s most recent 2011 home energy use data, a Saskatchewan home consumes an average of 30,555 kWh/year (110 GJ), of which electricity for appliance use is 8889 kWh/year (32 GJ).

Drum roll please.

… Actually first, some clarifications. All I have is our actual overall energy use. I cannot separate out Heating vs. DHW vs. Appliances unfortunately, although this would be interesting. The following information is taken from the solar panel’s generation and the Electrical meter. I tracked each month and have recorded it below.

OK, now the drum roll.


2) Actual Energy Consumption and PV Generation

January: Solar generated = 315 kWh vs. Energy Use = 3323 kWh

  • Yikes! I was a pretty worried when I saw this. That being said, January was very cold and has very short, dark days (-20° to -30°Celsius most days. We kept the house around 71°F).

February: Solar generated = 553 kWh vs. Energy Use = 2706 kWh

  • February is always a cold month. Although you can see the solar was getting a bit more sunlight already as the days lengthened.

March: Solar generated = 603 kWh vs. Energy Use = 1716 kWh

  • This was getting a bit better still. I lowered the house temperature to 69°F. It was getting warmer outside and more solar gain.

April: Solar generated = 979 kWh vs. Energy Use = 1385 kWh

  • April was warm and sunny. Nice spring weather. Started to not need the in-floor heat on at all during the day, but still ran it during the night.

May: Solar generated = 960 kWh vs. Energy Use = 1029 kWh

  • Almost net zero for the month. It was a very nice month. We were running our river pump frequently to water new grass, which I think increased energy use quite a lot.

June: Solar generated = 1434 kWh vs. Energy Use = 989 kWh

  • Net Positive in a big way. Beautiful month. Obviously the longest days of the year.

July: Solar generated = 956 kWh vs. Energy Use = 511 kWh

  • The first two weeks of July were cloudy and rainy which is unusual for July.

August: Solar generated = 950 kWh vs. Energy Use = 645 kWh

  • This month was very rainy as well, which again, isnot normal. Usually August is very hot.

September: Solar generated = 778 kWh vs. Energy Use = 611 kWh

  • Cool and cloudy. I replanted grass seed and was running the river pump a lot again.

October: Solar generated = 315 kWh vs. Energy Use = 1478 kWh

  • October sucked!! 315 kWh is the same as January! It snowed on October 4th. We had to turn the heat back on. There were only 2-3 sunny days all month.

November: Solar generated = 390 kWh vs. Energy Use = 1750 kWh

  • Cloudy month, but had some mild days mid-month with above freezing temperatures. Still, we generated more solar in November then October, which should not happen.

December: Solar generated = 229 kWh vs. Energy Use = 2857 kWh

  • Shortest days of the year and extremely cold (-40°F). What do you expect?

Actual Totals:

Actual Solar PV Generated = 8189 kWh

Actual Household Energy Consumed = 19,000 kWh

Actual Total Energy Used (consumption – PV) = 10,811 kWh


3) Discussion

I’m extremely pleased with these numbers! I’ve been waiting for two and a half years to know what our actual energy use would be.

We actually used less overall energy then was predicted by both the HOT2000 (19,328 kWh/year, although it was close) and a LOT less then PHPP (22,868 kWh/year), which is surprising that it was so off… It makes me wonder how close we would be to meeting the Passive House standard given the actual energy use is 3868 kWh less then it predicted… Hmm. Maybe we should have tried to hit that airtightness target of 0.6 ACH after all. Oh well.

Nonetheless, the overall energy use of 19,000 kWh is very good (and such a nice round number too!). We did not do anything different in terms of our behaviour except to just be smart and not be wasteful. I still baked bread every weekend and we used our larger appliances just like we normally would. We have two refrigerators and two deep freezers in the house. All the lights are LEDs. We try to hang our clothes to dry. We used our wood stove occasionally, maybe 2-3 times per week, but mostly just for ambiance and occasionally on the extremely cold days. That being said, based on the predicted numbers, the heating energy likely accounts for about 50% of our overall energy use. Makes me wonder too how much better we could do if we burned wood a bit more often?

As for the actual solar PV generation (8189 kWh), it pretty well split the difference between the installer’s predicted 9300 kWh/year and the PHPP prediction of 7321 kWh/year. I think this past year was on the cloudier side for sure. We had a lot of rain in the Spring and even more in the Fall, which is very unusual. Followed by an extremely early snowfall which seriously cut into our PV generation (see October – brutal). It probably would be closer to the installer’s prediction on a typical year (will have to see what 2017 brings).

Still based on the actual numbers, our solar panels did cover nearly 45% of our overall energy use for 2016. We would however need to double our solar panels (add another 6.2 KW array) to meet Net Zero with consistency year to year. Who knows, maybe in the coming years the costs will drop more and perhaps government incentives will increase. One can hope.

Comparing our house to the average Saskatchewan home consumption of 30,555 kWh, we did very well. Using 37% less energy then the average home. And when you take into account the solar energy generated that drops us further to using 65% less energy then the average house! Sweetness.

Considering that we are completely on electric energy, it makes sense to make the house as energy efficient as possible. The cost of electricity for us is $0.12224/kWh (while cost for natural gas power is about $0.04/kWh equivalent), which works out to an electricity bill of $1321.54/year (10,811 kWh x 0.12224). We do however have to pay a basic service fee of $32.61/month (even when we are net positive in a month) which sucks and then 5% tax. That brings our absolute costs for the year to $1798.50/year or $149.88/month, which is about half the cost of our previous homes power and electricity bill. I’m ok with that.

 

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