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SOLAR IRRIGATION FOR HIGHER LATITUDES

We sometimes hear that people living far from the equator (at higher latitudes more than 30 degrees north or south) think that solar energy is not a practical option for them – but they are wrong.

This myth stems from decades ago. Back then solar panels were a lot less efficient and a lot more expensive than now. In countries such as the UK, northern parts of the USA, and even southern parts of South Africa, you would have needed huge panel arrays to capture enough sunlight to provide a useful amount of energy for everyday use.

However, thanks to a massive increase in efficiency, alongside a dramatic drop in cost, solar panels are now an option for everyone. From powering streetlights and homes to water pumps for irrigation.

Solar energy away from the equator


Map shows the great potential for solar pv panels rights across the globe (source: The World Bank 2019)

Countries near the equator receive the most solar radiation (sunlight), but plenty of sunlight does also reach higher latitudes.

The reason countries nearer the equator have more available solar energy is due to the tilt of the Earth relative to the sun. Sunlight hits countries near the equator more directly, travelling through less of our atmosphere, concentrating the energy on a smaller amount of land.

In higher latitudes, this same amount of solar energy must travel through more of our atmosphere. This has the effect of scattering/reflecting more of the sunlight away before reaching the land at a greater angle, spreading it out over a larger area. This means the available solar energy per square metre is lower the further (or higher) you go from the equator.

The amount of solar radiation reaching these higher latitudes also changes throughout the year, with more available during the summer – and during the warmer, growing seasons, when irrigation is needed most!

Making the most of this solar energy

Solar panel technology has come a long way, and it is now easy and affordable to find a solution that will work for you no matter where you are. Here’s why…

1. Improved efficiency of solar panels
Solar panels now work well enough to produce a useful amount of energy from the available sunlight in higher latitudes, without the need for those huge arrays.

The efficiency of a solar panel is a measure of how much usable energy can be produced from the amount of sunlight that hits the panel. This is shown as a percentage. In the 80’s, even expensive solar panels were only around 15% efficient, but now affordable options can be up to double that. This may not sound like much, but it really does make a significant difference.

Also, solar panels are more efficient at lower temperatures. Solar panels perform best between 15C (59F) and 35C (95F). On a sunny day in many high-latitude countries solar panels will be more efficient compared to hotter countries near the equator.

2.       Reduced cost of solar panels

At the same time as the efficiency improvements, prices for solar panels have dropped drastically. Back in the early 70’s, it would cost over $100 per watt of solar, but this decade it is now just $0.20 per watt.

This means that solar panels have never been more affordable – not something we can say about petrol or diesel at the moment.

3.       Greater availability of solar panels

Solar panels are now easily available in most countries. Affordable and reliable panels can be found in many ‘high-street’ stores and not just from specialists. It is now easier than ever to find one that fits your needs.