Making the most of your solar generated electricity
Posted by Chris Rudge on 23 February 2012 at 9:55 am
A lot of people ask how they can make the most of the power generated by their solar PV system. This question is especially important now the feed-in tariff (FiT) rate is (or will be) 21p as you will want to get the best from your investment.
You will receive an export payment which will be 'deemed' to be 50% of your generated power at 3.1p a unit, so it pays to use as much of your PV power as possible. Until smart meters are fitted it will not affect your export payments at all!
Most solar PV system owners soon work that it's good to run as many electrical appliances during the day as they can. You should for example use your washing machine and dishwasher during daylight, as even on a low light day the operation will be supplemented by solar power. Sunny days can probably run the whole appliance!
You could also consider changing your lifestyle a little. Use a slow cooker more than you do now, cut the grass with an electric mower (not petrol) in bright sunlight (not such a tough thing to do). There are so many other little electrical things you can use, which all add up: charging laptops, batteries & phones. Do all this in daylight if you can. Simply put: try and use as much of your power as you can during daylight.
On a slightly unrelated note, your household lights will be used mostly at night when the PV system is not generating at all, so it really does benefit you to pay a little more and install good quality low energy lamps. Most people nowadays do just this, but the real culprit I see again and again in houses and retail outlets are downlights and spotlights using 50W GU10 type lamps. Ten of these power-guzzlers will use 500W of power, or around £85 a year, even if only used for 3 hours a day.
Until recently, there have not been decent low energy replacements, being stuck with compact flourescents. However 5w warm white LED lamps have come down in cost and will provide the same light output as a 50W tungsten. Our 10 lamp power-guzzling room will now only consume 50W or £8.50 a year!
Purchase cost of these devices have fallen to around £10 each, but unlike tungsten, they have a life of around 25,000 hours and do not keep blowing filaments. They will pay for themselves in just saved power within 2 years.
One item that keeps coming up in conversation with our customers is the use of a simple timer on their immersion heater. On the surface it's a great idea to set up a timer that will switch on your hot water immersion at 11am and off again at 1pm, thus taking advantage of the midday sun. However, even if you had a 4kWp system and only used this method during spring, summer and autumn, your 3kW immersion would use more power than it saved due to weather, cloud, etc.
This midday timer setup is quite common use, and made us start thinking of a better way to achieve the same result without buying power from the grid. The resulting auto Immersion Relay is proving a popular item we now sell. Its an ideal supplement for gas and oil users.
About the author: Chris Rudge is a qualified electrician who specialises in renewable energy.
If you have a question about anything in the above blog, please ask it in the comments section below.
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