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Using free solar electricity

The main strategies for using lots of free electricity are:

  • Try and use electricity when you are generating most, noon on a sunny day. Due to weather conditions, your PV system may not generate most electricity at noon, check the 24 hr weather forecast and use electricity when the weather forecast show the brightest conditions. Try the BBC Weather website and set it to your location.
  • Try not to use more than you generate, you will have to pay for the extra you import. To limit what you import do not use more than one appliance at a time.

    When you turn on an appliance such as a washing machine it will use electricity: 2 kilowatts, for the duration of its cycle: 1 hour, using a total of 2 kilowatt hours. If your solar panels are generating 1 kilowatt then you will have to import 1 kilowatt for 1 hour to make up the difference, importing 1 kilowatt hour.

    If you turn on two similar appliances at the same time then you will use 4 kilowatts and will have to import 3 kilowatts for 1 hour importing 3 kilowatt hours. If you run the appliances one ofter the other then you will import 1 kilowatt for 2 hours importing only 2 kilowatt hours.

If you are out during the day it is difficult to put these strategies into effect. The answer to this problem is to use time switches to turn on your appliances. Many modern dishwashers, washing machines, etc have built in delay start timers, these are ideal.

© J. Ansell 2015