The above figures and graphs present the real-time data from the Community Centre solar system.
The current status shows that the array and its four inverters are operating normally. The instantaneous AC power produced by the array is shown by the "doughnut" graph in the middle. When the system is at 100% production (achievable on the sunniest of days in June/July near local noon) the ring will complete the circle, showing its maximum achievable production of 85.0 kW. Two energy generation figures are to the right: today's generated energy in kWh and the energy generated by the system since installation in MWh.
What is the difference between kW and kWh? A kWh (kilowatt-hour) is a unit of energy, while a kW (kilowatt) is a measure of power. What's the difference? Energy is a measure of how much "fuel" is contained within something, or made or used by something over a specific period of time. The kWh is a unit of energy. So when we talk about what the solar array has produced over a day or over its lifetime, we need to talk about energy, hence kWh. Power, on the other hand, is the rate at which energy is generated or used. The kW is a unit of power. So when we talk about the instantaneous amount of "stuff" the solar array is producing "right now", we need to talk about power, hence kW. Old-timers know the kW as horsepower. In the same way that a car or engine used to be rated in horsepower, they can now be rated in kW, which is the rate at which they use energy. (see energylens.com).
Lastly, the bar graph at the bottom breaks down the accumulated energy generation into daily bars, monthly bars, and yearly bars, so that we can compare different time periods. Notice how production is much lower in winter months. Also notice that the array has produced more energy in 2016 than it did in 2015, keeping in mind that the solar array was first switched on in mid-September 2015.
The Town of Devon has installed a 100 kilowatt solar photovoltaic system on the Devon Community Centre, a significant milestone in the town’s plan to transition into one of the first net-zero communities in Canada. Through a unique solar panel leasing program from ENMAX, The Devon Community Centre’s electricity needs are now being completely met courtesy of the sun.
“At the heart of every community is a gathering place where people connect, plan and celebrate,” said Devon Mayor, Stephen Lindop. “So transforming Devon’s Community Centre into the first net-zero building in our town with this 100 kilowatts DC system is both symbolic and a sign of things to come.”
Engineered and installed by Great Canadian Solar, the community centre installation features 393 panels that can meet 100 per cent of the building’s net annual electricity requirements. The system can offset about 73 metric tonnes of GHG emissions – the equivalent of taking 14 cars off the road annually.
The solar array itself will only degrade by 0.5% per year so the longevity of these systems is excellent. A system install today could be producing well for 50 years and likely longer.
The initial investment of $117,000 is funded through the New Infrastructure Reserve. The remaining cost will be paid over a 15 year lease, at the end of which the Town of Devon will own the solar system. Since solar systems last a long, long time, the Town views this as an economically sound investment.
Some residents have also asked about re-shingling the roof. The community centre was re-shingled in 2014, using shingles that last 50 years, on average. The solar panels also partially protect the roof and extend the life of the shingles.
The professionals at Great Canadian Solar have designed the solar panel layout for maximum energy production and to ensure that we achieve our electric net-zero goal. Factors such as which direction the arrays are facing, if there is shading and snow cover during the winter are all considered in the design.
The solar panels capture the sun's rays and generate direct current. An inverter inside the building converts the direct current to alternating current or the “usable” electricity needed to run the community centre. Inside the community centre, a bi-directional meter measures the electricity flow. On a sunny, summer day, with long daylight hours, the community centre will produce more electricity than it uses. Excess electricity will flow into the grid, translating into dollar value credits for the facility.
The combined excess of summer production and winter energy shortfall should balance out and offset each other to make this building electrically net-zero. An average solar system uncleared of snow will only produce 4-6% less energy annually than if cleared of snow. As this represents a very small amount of financial payback we will not be clearing the array of snow, to make this system free of maintenance costs.