How grid-connected home-generated electricity works
Posted by Cathy Debenham on 2 February 2011 at 8:45 am
Understanding how a home microgeneration system switches from solar PV (or wind) generated power to mains electricity and back again is much simpler than you might think. It's all completely automatic and requires no human intervention.
The system comes with an inverter, which converts the home generated electricity from direct current (DC) to alternating current (AC). It converts it at a slightly higher frequency than the electricity that comes from the national grid.
This means that whenever your microgeneration system is producing electricity, appliances in your house will draw on that electricity first. If there isn't enough it will top it up by calling for more from the grid. It all happens smoothly and continuously, so you're unaware of what's happening.
The more of your own generated electricity you use, the more you benefit. The cost of importing electricity is significantly greater than the amount you are paid for exporting your surplus. The trick is to try and do the things that use most electricity when the sun is shining.
Given that many people are out of the house for much of the day, this isn't always easy. But gettting a timer switch so you can run the washing machine or dishwasher or turn on the immersion while the sun is out will make a difference.
Photo by Stewart Chambers
If you have a question about anything in the above blog, please ask it in the comments section below.
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