Solar Power

In NZ 45 per cent of homeowners say they’ve thought about installing solar. Solar power is becoming an increasingly popular investment and as we gain more knowledge and the surrounding technology becomes more advanced – solar energy for your home may seem to be a no-brainer!

Yet due to the initial investment t’s a decision each homeowner must carefully consider.

If you are choosing Solar Power purely to save money on your power bill, the length of time it takes to payback these costs will increase as the costs increase. Solar systems don’t generate any power at night, so if this is when you use the most power you’ll need to look at some form of battery to store the power your system generates during the day. But be warned, Batteries are expensive.

In the southern hemisphere your panels need to face north to get the best power production. Your roof will ideally be north-east- to north-west-facing, with a 15 to 45° pitch. Falling outside this range cuts down how effective the system will be. Selling it back isn’t financially attractive (the buy-back rate from power retailers is 7 to 8¢ per kWh). A better option is using the power produced on your roof during the day.

Power usage peaks in the morning and evening for most households. We use more electricity in the winter, and the peaks are higher too, as we turn on heaters and use more hot water. To get the best payback from solar PV, you need to use as much of the solar power as possible as it is generated. Some of the power used in morning and evening peaks can be shifted. Using timers to delay and stagger appliances could be one solution, another is switching electric water heating to come on during the day.

Ultimately, getting the best bang for your solar buck requires a home with large daytime power use, plus a behavioural change for your household to bring consumption into line with production. The ideal solar PV system for your home is sized so you can use most of the power it generates, selling as little as possible back to the grid.

While the benefits of solar are clear, there are a few drawbacks to weigh-up before making the leap. Here, we give you 5 pros and 5 cons of running your home on the power of sunlight.

1. Solar is sustainable

The sun will always be there, providing heat and light. It’s an infinite source of energy.

2. Lower electricity costs

Homeowners can largely, or even entirely, offset solar power installation costs by choosing a lease or power purchase agreement. Also, excess unused solar energy can be stored in the grid and be sold back to your utility.

3. Solar PV systems require little maintenance

Once your solar panel system is set up, that’s about it. Cleaning the panels twice a year is all the maintenance that is needed. Most installers will include a 20-25 year warranty.

4. Solar energy technology is advancing

Innovation around solar is constantly happening. As research continues we can expect solar panels to get more and more efficient and become more affordable.

5. Solar power is very versatile

As well as in your own home, Solar power can be used in many different situations such as in rural areas where there’s no grid to depend on and in gardens and farms where low-cost irrigation techniques are needed.

1. Solar energy can be irregular

Solar panels aren’t hit with sunlight 24/7. Solar power can’t be generated at night, and less power is produced during the winter, or in very cloudy and rainy weather.

2. Solar power storage is costly

Though solar components are coming down in price, batteries and other ways of storing excess solar power can still be quite expensive. Fortunately with good power management, typical homeowners can utilise most of the energy that’s produced during the day.

3. Solar energy manufacturers and installers produce pollution

Solar energy itself is clean energy — but in making the panels, some manufacturers can emit harmful greenhouse gases, such as nitrogen trifluoride (NF3) and sulphur hexafluoride (SF6).

4. Solar can require rare, irreplaceable materials

The unique features of solar panels often demand the use of rare materials, such as the cadmium telluride (CdTe) found in thin-film solar cells. So, harnessing ‘free’ sunlight energy comes at the cost which everyone needs to be aware of.

5. Solar systems take up space

The typical home requires 20 to 100 W/m². While the power density of solar makes it viable for homes, not all panel types are perfectly efficient in making use of solar radiation. This means a fair amount of space is needed for the panels, either on a rooftop or on land for ground-mounting.

If you want to calculate the exact requirements for your own home to determine if Solar is worth while for you, have a look at this handy Solar Calculator: https://www.energywise.govt.nz/tools/solar-tool/