November 29, 2021

How much direct sunlight do solar panels need?

An aerial view of a residential neighborhood with solar panels.


Whakatane, Richmond, New Plymouth, Rotorua, Napier - these are the top five sunniest places in New Zealand, according to research from the National Institute of Water and Atmospheric Research.

In this article we will cover

Whakatane, Richmond, New Plymouth, Rotorua, Napier - these are the top five sunniest places in New Zealand, according to research from the National Institute of Water and Atmospheric Research. You might think that, of all the places in Aotearoa, these are the places that are best suited for solar power.

But the amount of direct sunlight in a given area doesn’t tell the full story about the viability of solar for a given home or business. Let’s look at what’s missing.

How much direct sunlight do solar panels need?

Let’s start with the obvious: the more sunlight a solar power system gets, the more energy you’ll generate. 

However, as photovoltaic solar panels have become more advanced over the years, their efficiency has improved, and they’ve become better at converting energy from the sun into electricity. That, combined with their costs coming down, is why they’ve become so popular as an alternative method of generating electricity.

However, that doesn’t mean that solar panels will suddenly stop working just because there’s a cloud overhead! Solar panels rely on the photons from sunlight, rather than the sunlight itself. 

Put shortly, solar panels do not need to be installed in direct sunlight to work. They don’t need a prescribed amount of direct sunlight in order to generate enough power, and they even work in typically less sunny countries like the United Kingdom and Germany.

The factors that really impact solar panel performance

Solar photovoltaic panels, while not needing direct sunlight, do need to be placed in the right position and out of the shade in order to work optimally. Overhanging trees, buildings, chimneys and anything else that causes shade can impact the effectiveness of any solar panel system. 

It’s best to keep trees trimmed back, or avoid installing solar PV in areas that may get shaded in the future from construction work. Check with your local council and neighbours before getting solar installed!

This is particularly important if you have solar panels that are ‘daisy chained’ - that is, if one panel starts to drop in performance, the others will as well. ZEN Energy panels don’t have this issue, so if you’ve worked or are planning to work with us, this will be less of a concern.

Other factors that impact solar panel performance include:

  • The size of the system you’ve installed
  • The efficiency of your inverter/batteries
  • The orientation of your system (north-facing is generally best)
  • The tilt of your solar power system
  • The power demand that your home has
  • How advanced your solar system is

As you can see, the amount of sun your solar system receives is just one of many factors that impact its effectiveness. Solar power systems have become far more advanced in even the last 10 years, featuring solar concentrators to maximise the amount of light reaching their PV cells, ensuring that even cloudy days result in solar generation - if you’ve got the right system.

A poorly installed or chosen solar system in the sunniest place in New Zealand (Whakatane, by the way) could generate less power than a properly evaluated and designed system in the depths of a Dunedin winter.

If you’d like to take advantage of the free, clean energy currently beaming down on your roof, get in touch with the team at ZEN Energy. No matter where you are in New Zealand, and no matter how much direct sunlight you get, your home or business may still be suitable for an investment in solar.

Call us today to discover how we can help you live free under the sun.

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