Post One: Solar?
I’m from Edmonton, but am currently living and working out of Calgary for the summer. In my first week in Calgary I was in a line at a café and I started chatting with the girl ahead of me. She asked what sector I was interested working in, to and I replied “Renewable energy or the transportation sector.” She gave me a strange look and asked what I meant by “renewable energy.” I gave examples: solar energy, energy from the sun, or wind energy, energy from the wind… She looked at me bewildered and asked “You can get energy from the sun?”… to which I replied..:
I told that story to my Calgarian friends, and they assured me (despite what my Edmonton bias was telling me) that people in Calgary do know what renewable energy is and that girl was the strange minority. But honestly, until a few years ago, I didn’t really understand how solar worked. I knew it was energy from the sun… but how does that happen? And can it work in places like Alberta with lots of snow and cold?
Here are my answers to those questions:
How does solar work:
(I will now go on a nerdy tangent)
A solar panel is composed of several solar cells connected together. A ray of light (photon) hits the panel and knocks electrons free from atoms, creating a flow of electricity. Each cell is a small stack of two pieces of a silicon or any other semi conductive materials.
Time to dive more into this...Ready?
For electricity to flow, an electric field needs to be established. For solar, the fields are created by separating opposite charges – the polarized two pieces of silicon. The upper piece of silicon is “doped” (something is added to it to give it a charge) to give it a negative charge, and the bottom layer is “doped” to give it a positive charge. It's kind of like a concentration gradient of charge where electrons flow from areas of higher electron concentration to areas of lower electron concentration. Light induces the flow of charge by increasing the number of electrons on the negative plate and causing electrons to flow from the more negative plate to the positive plate. The light gives that extra imbalance of electrons that starts the flow of electrons (negative charge) or if you want to think of it as the movement of holes (positive charge) through the electrical field (but the flow of empty space would be in the opposite direction as you would think of as the flow of electrons..its another way to say the same thing really.. seems a little wack to me but I've just heard it said as the movement of holes rather than electrons). The flow of charge is electricity which can be harnessed for use as long as there is the sufficient infrastructure of the wires and metal plates to create the closed circuit!
[Gahh!..science is so cool.]
If you’d rather hear Brown University explain it rather than me : https://www.youtube.com/watch?v=UJ8XW9AgUrw
How is solar affected by Weather + Snow + Night?
- Solar works best in unclouded cool sunny days; however, solar also works in cloudy, rainy and cold days! It actually work best in cooler temperatures than hotter ones. When it is cloudy, the light is diffused which makes the panel less efficient. For example, Germany is not a particularly warm or sunny place – in fact, most of Alberta has better solar potential than anywhere in Germany – however, Germany remains a world leader in solar energy and is able to generate a great deal of its electricity using solar. So solar can still be an option even when the light is sometimes diffused. Plus, there is some cool research on increasing performance of solar on cloudy days..so maybe that is something that will improve in the near future.
- Snow does decrease and can stop a solar array because it blocks cells, preventing light from getting through – and no light = no power. So in Alberta, there will likely be a few days that panels won’t generate too much energy, but since they are at steep angle on roofs, they don’t collect a lot of snow unless it is a really snowy stretch of winter.
- Solar doesn’t generate much electricity at night. This is where storage becomes important if the home is powered solely by solar, which is uncommon in the city. With any house still connected to the grid, energy produced and not used during sunny periods is put back into the grid, and energy that is in demand when solar isn’t producing is taken from the grid.
- Alberta Community Solar Guide
- Solar Society of Alberta Website