The Best Conditions for Generating Solar Energy

What Factors Affect Where Solar Panels Are Placed?

The Positioning of the Solar Panels

Solar panels work by harvesting the light from the sun and instantly converting it into usable electricity. The following factors, which affect the placement of the panels, are focused on ensuring the maximum amount of sunlight possible reaches the panels throughout the day.

The Direction of the Roof

The direction the roof faces is one of the biggest factors in the positioning of solar panels. For maximum efficiency solar panels should be placed on a south facing roof. If the roof faces south west or south east there will be very little difference in the output. Do not worry that you cannot install panels if your house faces east/west, or that the panels will not receive enough light to be cost efficient. Studies have shown that east or west facing solar panels only produce up to 15% less electricity; plenty enough to power your house and guarantee a return on investment.

The Angle of the Solar Panels

The angle that the solar panels are mounted at is another factor to consider. For optimum efficiency your solar panels should sit between 30°-60° from horizontal (flat). This means that if you have a flat roof, you should consider an angled mounting bracket to ensure your panels see the maximum amount of sunlight.

The optimum angle does change depending on the time of year. During the winter months when the sun is lower in the sky it may more more efficient for your solar panels to be placed at around 60°. In the Summer when the sun is high they might be more optimal at 30°. In order to maximize solar output from the angle of the sun, you could invest in an adjustable mounting bracket. However, the difference is not vast and you will still see enough output from your panels if they remain at the same angle all year.

Direct Access to Sunlight

To gain the maximum output from your solar panels they must be exposed to sunlight as much as possible. This means that they should not be placed anywhere that will will be shaded by trees or other buildings at any point during the day.



What Are the Best Conditions for Generating Solar Energy?

Weather Conditions

A clear, bright day is the best weather condition for optimal solar panel output. On a clear, non-cloudy day the panels receive the maximum amount of light possible. As solar panels run off light and not heat, it does not have to be a particularly warm day for the panels to work well.

Wind and rain do not affect the output of solar panels and can actually help to keep them clean and free of debris. Cloudy days are the least optimal for producing solar power. However, even on very cloudy days your panels can still potentially produce up to a third of their maximum output.

Time of Year

The length of daytime changes throughout the year in the UK. Our days are longer in the summer months and shorter during winter. The most optimal time for producing solar energy is the summer months, between June and August. In June, July and August, there is an average of 16 daylight hours each day in the UK. In April, May and September there are still on average 13-15 hours. Even in the shortest daylight months, December and January, the UK still has around 8 hours of light every day.

At the moment solar panels cannot store energy. This means that they can only power your house during the daylight hours, when they are able to instantly convert sunlight into electricity. There are solar batteries which store excess energy produced throughout the day for use at night. In the near future we may even be able to store solar power over the light summer months in order to benefit from it over winter time. Solar battery technology is still relatively new and untested. However, it is rapidly improving and the ideal of 24 hour solar power, 365 days a year, is not too distant a dream.

Type of Solar Panels

It used to be accepted that the most expensive, monocrystalline, type of solar panels were the most efficient. Recent developments have lead to monocrystalline and polycrystalline panels becoming very similar in both price and output. There is another, fastly growing, type of solar panel called ‘thin film’ panels. Thin film panels are thought to work better than traditional crystalline panels in cloudy conditions. Therefore, if you live in an area of the UK with traditionally low light conditions, it may be worth considering thin film. Thin film panels are a newer technology, and whilst they are showing some promising qualities, they are typically not yet as efficient as traditional panels.

For a full comparison of thin film vs crystalline panels see our thin film page.


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