Solar Explained
The Simple Version of How Solar Works
Thinking about going solar? You’re not alone.
More and more Kiwis are turning to the sun to slash their power bills and do their bit for the planet. Let’s break down how it all works without the technical jargon. When sunshine hits your roof panels, they convert that sunlight into electricity.
But here’s the catch – they produce DC power, and your home runs on AC. That’s where an inverter comes in, transforming that power into something your appliances can actually use. What happens to extra power? You’ve got options. Use it right away, store it in a battery for later, or send it back to the grid (and maybe get paid for it).
What You’ll Need for a Solar Setup
The Panels
These are your workhorses, and they're more sophisticated than they appear. Each panel contains multiple photovoltaic (PV) cells made primarily of silicon. When sunlight hits these cells, it excites the electrons inside, creating an electric flow – that's the photovoltaic effect in action.
Not all panels are created equal, and in New Zealand's varied climate, quality matters. Here's what to consider:
- Efficiency ratings: Most residential panels range from 15-22% efficiency. Higher efficiency panels generate more electricity in the same amount of space, which is crucial if your roof area is limited. They cost more upfront but can deliver better long-term returns.
- Types of panels: You'll typically choose between:
- Monocrystalline panels (sleek black appearance, highest efficiency, longer lifespan)
- Polycrystalline panels (blueish speckled appearance, slightly less efficient but more affordable)
- Thin-film (less common, flexible, and work better in high temperatures but require more space)
- Temperature coefficient: This matters in New Zealand's sunny spots. Panels actually lose efficiency when they get too hot, and a lower temperature coefficient means better performance on those scorching summer days.
- Durability: Look for panels tested for salt spray resistance if you're near the coast. Wind and hail resistance ratings are also important, especially in storm-prone regions.
- Warranty: Most quality panels come with a 25-year performance warranty (guaranteeing they'll still produce at least 80% of their rated output after 25 years) and a 10-15 year product warranty covering defects.
In New Zealand conditions, quality brands that perform well include LG, REC, Sunpower, Panasonic, and Trina Solar, though there are many other good options on the market. Your installer should be able to recommend panels that suit your specific location and needs.
The Brains: Your Inverter
The inverter is really the unsung hero of your solar system. It takes the DC (Direct Current) electricity generated by your panels and converts it into 230V AC (Alternating Current) power that your home can actually use.
Inside the inverter, sophisticated electronics work to sync the electricity with your home’s power supply. The inverter constantly monitors your system’s performance and adjusts in real-time to maximize efficiency. Most modern inverters can even connect to your Wi-Fi, letting you track performance from your phone.
You’ve got several options to consider:
- String inverters: The most common and affordable option. They’re called “string” because they connect to a series (or string) of panels together. The downside? If one panel gets shaded or dirty, it can drag down the performance of the entire string – a bit like Christmas lights where one bad bulb affects the whole chain.
- Microinverters: These small units attach directly to each individual panel, converting DC to AC right at the source. They’re more expensive upfront, but allow each panel to perform independently. If trees shade part of your roof in the afternoon, or seagulls leave their mark on one panel, only that specific panel’s output is affected.
- Hybrid inverters: These clever units are designed to work with both solar panels and batteries, making them perfect if you’re planning to add storage later. They manage the flow of electricity between your panels, battery, home, and the grid, often with smart features that can prioritize self-consumption or backup power during outages.
Good quality inverters typically last 10-15 years, slightly less than the panels themselves, so you might need to replace it once during your solar system’s lifetime.
Smart Bi-Directional Meter
This is a crucial component that often gets overlooked in the solar conversation. Your standard old-school power meter only measures electricity flowing into your home from the grid. A smart bi-directional meter, however, can measure electricity flowing both ways – what you take from the grid AND what your solar system sends back.
Here’s why it matters:
- It accurately tracks excess power you export to the grid, ensuring you get credited properly
- It provides detailed data on your energy consumption patterns, helping you optimize when to use appliances
- Most come with digital displays or apps showing real-time power flows
- Some smart meters can communicate directly with your power company, eliminating manual meter readings
When you go solar in New Zealand, your power company will typically organize the installation of a bi-directional meter as part of the connection process. There’s usually a one-time fee for this meter upgrade, but it’s essential if you want to participate in any buy-back scheme.
Mounting Hardware
This needs to be rock-solid. Remember, your panels will face everything from Wellington’s howling winds to Central Otago’s heavy snowfalls. Proper installation facing north (ideally) will maximize your sunshine capture.
The Electrical Bits
Cables, connectors, breakers – all the behind-the-scenes components that need professional installation. This isn’t a DIY job – you’ll need a licensed sparky to keep everything safe and up to code.
Batteries (If You Want Them)
Adding a battery isn’t essential, but it’s becoming more popular. Why? It lets you use your solar power at night or during cloudy spells. Tesla Powerwall, LG Chem, and Sonnen are common options here.
Tracking Your Power
Most systems come with an app that shows you exactly how much power you’re generating and using. It’s pretty satisfying watching those savings add up in real-time!
Is Solar Worth It?
Selling Power Back
When your panels are pumping out more electricity than you’re using, you can feed it back to the grid. The catch? What you get paid varies hugely between power companies – anywhere from a decent 7-12 cents per kWh to a measly 4-5 cents. Shop around.
The Bottom Line
For many Kiwis, absolutely. If you’re home during the day using appliances, or invest in a battery to use that solar power at night, the savings can be significant. Plus, there’s something pretty satisfying about generating your own power.
The best first step?
Get a proper assessment of your home. Every property is different, and a professional can tell you exactly what kind of setup would work best for your situation.