At the start of every year the media has a field day with NIWA’s annual report into the average rainfall, temperatures and sunlight hours of towns and cities around the county.
As with any list of numbers, someone has to come first and someone has to finish on the bottom – and when it comes to sunshine hours, this means a somewhere in New Zealand gets to have bragging rights over the country’s “sunniest” location while somewhere else has to console itself after being dubbed “cloudiest city”.
This January’s headlines were topped by Richmond at the top of the South Island, which claimed “sunshine capital for 2016” with 2840 hours (the most ever recorded in New Zealand) while Palmerston North had less than half than Richmond with 1645 hours.
When you look at the top sunniest centres (Richmond, Appleby, Blenheim, Takaka, New Plymouth and Nelson round out the top-six) you might think that they’d be the best-suited places to install a solar system and turn all that free sunlight into usable power.
And, certainly, those totals are important. But they don’t tell the full story – when you calculate how to arrange solar panels and how much power you are able to convert from your solar array it’s important to pay close attention to a number of factors.
When you get a personal in-home energy audit from Harrisons, we’re not going to look simply at NIWA’s figures about how much sunlight you get where you live, nor are we going to simplify potential sun-hours by looking at which latitude you live on – yes, these factors matter, but they don’t tell the whole picture.
Other factors include:
When you use your power: If you need peak amounts of power in the morning and evening, then it might make sense to set up your panels to gain most sunlight during those times of the day. Equally, if you’re going to set up a system with battery storage then you want to make the most of all potential sunlight to ensure those batteries are fully charged, ready for use at night.
How your roof is aligned: Is your roof suitable for solar panels? North-facing roofs are, of course, best but east or west-facing roofs can also generate good amounts of power. Flat roofs can mean mounting your solar panels at an angle to make the most of available sunlight.
Shade and shadow: You might live in the sunniest part of the country but that’s not going to matter if your roof is overshadowed by a neighbouring apartment block. While installing your solar panel in direct sunlight is ideal, our experts at Harrisons can determine a solution when it comes to shade and shadows.
Peak sun-hours: These refer specifically to how much solar energy is available during an average day and is calculated when the intensity of sunlight is 1000W per square metre. They rely on the time of day, the season and geography.
The system you choose: Setting up a system with a SolarEdge power optimizer from Harrisons increases energy output from PV systems by constantly tracking the maximum power point (MPPT) of each module individually. The MPPT per module allows for flexible installation design with multiple orientations, tilts and module types in the same string. When working with SolarEdge Inverters, SolarEdge power optimizers automatically maintain a fixed string voltage, allowing installers even greater flexibility with longer strings and strings of different lengths in order to design optimal PV systems.
After the sort of haphazard weather we’ve experienced in New Zealand this summer, it’s not a good idea to make a snap decision on whether a solar energy system is right for your household – and anyone who tries to sell you a system based on figures calculated simply by looking at where you live simply isn’t telling you the whole picture.
Instead, you need to get good advice about your energy usage and lifestyle and specific installation advice about your home and roof – and that’s why you should insist on a free in-home energy audit from one of our energy experts.