How Solar Panels Work In New Zealand

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How Solar Panels Work In New Zealand

12 September, 2017

We’ve all heard about how solar panels may reduce our monthly power bill and enable us live a more self-sufficient lifestyle, but not many of us know how solar panels actually work.

Solar panels have been around since 1884. Even back then they were dubbed to be the energy source of the future, likely to replace coal when the mines ran dry. Powering road signs, garden lights and even space shuttles are just a few of the day to day uses of solar panels, but how is it that they are able to maximise the sun’s light and convert it into usable energy that can power our home? And what are the real benefits of installing rooftop solar panels to our homes?


How Solar Panels Work

The sun is a magnificent presence. It not only lights our way and keeps us warm, it’s also imperative for the growth and well-being of all living things on Earth. As well as being the centre of our solar system it is a mighty giant that is capable of powering our homes.

Solar panels are made up of lots of photovoltaic cells. Photovoltaic sounds like a big word but all it really means is that these cells are able to convert sunlight into energy. Solar panels are basically a whole lot of these photovoltaic cells joined together to create a panel.

Getting more technical, each photovoltaic cell is made up of two layers of silicon. The bottom layer is infused with boron, which then gives off a positive charge, while the top layer is infused with phosphorous which gives off a negative charge. These cells, framed with metal conductive plates, then covert the sun’s light into usable energy which then flows through wires into your home.



Making the most of your solar panels

To get the most bang for your solar panel invested buck, it is important to weigh up how much energy you can generate and when that energy is generated so that you can position your solar panels to receive maximum sunlight for as long as possible. Take into consideration what time the direct sun is on your property. Do you receive more east facing morning sun? Or perhaps more west facing sun in the later parts of the day? If you’re lucky and get both you may consider placing a panel on both eastern and westerly facing aspects of your roof. You may also wish to consider trimming trees to make sure they are not casting shadows on your solar panel, cutting your solar power off hours earlier. You can use our Solar E-valuator tool to calculate how much solar energy your roof may harness and how much that energy could be worth!

Because solar panels alone cannot save the energy they collect from the sun, it is best to make sure you use the majority of your power during the sunniest part of the day, usually between the hours of 10am – 4pm. This means doing your washing, baking or vacuuming while the sun is out and about. Of course, this is easier if you are retired or work from home, but you could consider putting your major appliances on a timer or using devices like a power diverter to power your hot water cylinder during the day. This means that your dishwasher, washing machine, and dryer are all scheduled to switch on at pre-set intervals during the middle of the day when the sun is most likely to be at its fullest.

Another option could be to invest in a battery storage pack which allows you to store any power you are unable to use during the day. With a battery storage pack, you are still able to send any unused power back to the grid but only when your batteries are fully charged.


Benefits of installing solar panels

If you are looking to reduce your dependence on the grid, possibly lower your power bill, or potentially create a more stable power price, then solar panels are right for you!

If saving the environment is your focus, then you’ll be pleased to hear that solar power is a clean pure source of energy. Other methods of deriving energy for human use, such as coal or gas-powered plants, cause harmful gasses to be emitted into the air, contributing to pollution and global warming. These types of energy also rely on fossil fuels, which are a finite resource. Sunlight, on the other hand, is a reliable, sustainable resource which will be around as long as we are.

All of us have our favourite appliances that make doing those day to day chores a little less burdensome. Perhaps you hate hanging out the washing? Well, when the sun is providing your electricity for free there’s no need to feel guilty for throwing your towels in the dryer to get that extra fluffy dry feel. The same goes for using the oven or using the heat pump on a chilly winter’s day. Solar power takes the guilt out of using the - previously costly - appliances you love.

With the constant climb of power prices every year the idea of having a way to lock in the amount you are paying for power may seem quite appealing. When you convert to solar energy you are less exposed to price fluctuations in the electricity market brought about by low hydro lake levels or the price of coal and gas.


Selling Solar Power Back to the Grid

Any excess energy that you do not use can be sold back to the grid. The power buy-back rate differs greatly between power retailers so it pays to do your research to ensure that the power retailer you choose has the best deal for your energy consumption needs.

When it comes to getting set up with solar power, you’ll first need to consider what kind of solar power system is right for you. There are grid-tied systems, off-grid systems, and hybrid systems, which are a mixture of the two. If you’re intending to be completely self-sufficient, then you’ll be after an off-grid system. If your home is already connected to the grid then a grid-tied system is the way to go.

If you work from home and plan to use the majority of your power in the middle of the day, then your buyback rate will not be a huge factor. But if you don’t work from home and are unlikely to put your appliances on a timer to utilise your solar energy, then you will definitely want to shop around to ensure you are getting the best buyback rate you can.

As you’ll see from the figures below, the buyback rate of approximately 8c per kilowatt hours is a lot less than the average rate we pay for power (30c per kilowatt hours). While selling unused power back to the grid can’t hurt, it still makes more sense to try and utilise your self-consumption rates if you’re planning to go solar.


Solar Power Buy Back Rates NZ 





   Up to 10kW

   8¢ / kilowatt hours, + GST

   Mercury Energy


   8¢ / kilowatt hours, + GST

   Trust Power 

   Up to 10kW

   7¢ / kilowatt hours, + GST

   P2 Power

   Any size

  16c / kilowatt hours, + GST – For the first 50 kilowatt hours exported each fortnight only. 8c / kilowatt hours thereafter. Note: 16c rate may be waitlisted.



   4 - 7¢ / kilowatt hours ()


   Up to 10kW

  7c / kilowatt hours in the summer and 10 / kilowatt hours in the winter.

NB - Rates correct as of 18/9/2017 and are subject to change, check the electricity providers website for the most up to date rates.

There you have it! Our summary of how solar panels work in New Zealand. Book in for your Free HRV Home Assessment and start your solar journey. 

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