Today’s the summer solstice so a perfect time to write about the miracle of photovoltaic solar power.
When we built Casa Passive, as we like to call the McDonald Road passive house, we were aiming for Passive House Plus certification, which means the house is net positive for heating and cooling (i.e., generates more than it consumes). The data for our build put the energy consumption at 13 KWh/sq m/year, which beat the target by 2 KWh.
All well and good… but. Energy efficiency, like any new industry, generates its share of shysters. There are some very unscrupulous operators out there and I was conned by one on something called a “Sunpump”, which promised to use evaporator panels and a compressor (similar to a heat pump) to generate my domestic hot water and radiant heat.
The Sunpump was to be my water heating, in addition to a photo-voltaic solar system for electricity. The former was complete crap, but the latter has been brilliant. After 18 months of struggles with the Sunpump (the company folded, by the way), I replaced it with a conventional air-to-water heat pump by Carrier that has worked well since 2020.
But the problem remained that I was in deficit by 7 KW because the Sunpump never worked as promised — but that promise was part of our calculations. I already had 7.2 KW of photovoltaic solar on the roof, so I needed to boost that to get back to at least neutral. This year, helped by a government grant for renewable energy, we have added another 4 KW, bringing us up over 11 KW in total. The company that did this for me was solar specialists Hakai Energy, and they were professional, punctual, efficient and delivered exactly what was promised. They are the other side of coin from the Sunpumps of this world, and it’s fair to say the renewable/efficiency space is more and more populated by the good guys.
The upshot is that in these sunny days, I am far in positive territory in the energy generation vs. consumption equation now. Despite charging an electric car (and therefore buying no gasoline), in this billing cycle for my BC Hydro account I am up over 650KWh with still 10 days to go in the cycle. See the data in the figure below.
My consumption (bars below the line indicate surplus) Source: BC Hydro
The logic of solar power is irrefutable. It is now the cheapest energy in the world, even in a northern place like Vancouver Island. The price per watt for solar generation is now 1/100th of what it was in the 1970s, when solar was pioneered. (See the “Swanson effect” chart, which is 10 years out of date so it’s even less now). The problem of “intermittency” still exists, of course, because the sun shines at varying rates, or not at all. But in a place like BC, where I am grid-tied and my generation nets out, I can use our grid as a battery. Or, you can get batteries, the tech for which advances by leaps and bounds. Bottom line: I burn no wood, gas, oil or coal for my home.
The Swanson effect Source: Cleantechnica and Bloomberg
Burning oil or gas for a furnace you are using energy that was stored in the form of fossilized flora and fauna 65 million years ago. Using PV solar, my power left the sun 8 minutes and 20 seconds ago, which is the time it takes light to travel the 150 million kilometers from our sun to the third rock.
