A Guide to Buying Solar Panels

Solar panels are becoming increasingly popular with homeowners who are not just worried about rising electricity costs, but are mindful of the environment and want a system that produces greener energy as well. As time goes by, solar panels are becoming increasingly affordable regardless of the fact that the most generous incentive programs are now not an option for new applicants. But are solar panels right for you?

Here is a guide to buying solar panels.

How do solar panels actually work?

Materials that are made to produce electricity when light falls on them use what’s called the photovoltaic effect. Solar panels use this effect to convert energy from the sun into direct current (DC) electrical energy. An inverter then changes this into alternating (AC) current for a home’s electrical circuits. Any excess energy can be fed back to the electricity grid (which is where feed-in tariffs come into play), or it can be fed into a battery storage system to enable you to use stored power later (at night for example).

Solar panels work best when they are north facing, at an optimal angle, pointed directly at the sun and are not blocked by shading or trees. When buying solar panels, it’s worth remembering that their effectiveness also depends on the weather and where you live.

Are there different types of solar panels?

In terms of solar panels in Queensland, there is a range of different types of solar panels available, which include:

  • Monocrystalline panels. These are typically black in colour, have better temperature tolerance and are more efficient than multi-crystalline (or polycrystalline) models, which are typically dark blue. The differences result from the manufacturing processes of the silicon cells, however as a complex combination of many components, the overall performance does depend on more than just the type of cell.
  • Interdigitated back contact solar cells (IBC) or rear-contact solar cells. These are a variant of standard solar cells and they can be more efficient due to all of the electrical contacts being on the rear of the cell rather than on the front.
  • Thin film solar cells. These are constructed of a thin layer of photovoltaic material (like cadmium telluride, amorphous silicon or copper-indium-gallium-selenide) that sits on a base plate of metal, glass or other substance. They are generally less efficient and actually rare in rooftop arrangements, however the technology is evolving. Currently these can be seen in things like garden lamps, solar-powered calculators and building-integrated PV systems.
  • Bifacial panels. These have solar cells on both sides, back and front. When they are mounted in the same way as a regular solar panel, the front faces the sky (like normal), and the back picks up reflected and scattered sunlight from the roof. Their power output is dependent on how they are mounted, and because they’re not widely used yet, the industry is still working on an agreed standard in terms of rating their overall power output.

How many solar panels do I need?

When buying solar panels there are so many variables, and because at the moment owners don’t make a lot of money from feeding electricity back into the grid, you really need to maximise your own use of solar PV and minimise what you export.

You also need to consider things like inverters, batteries, grid vs. off-grid connection, and your roof space and orientation. It might seem logical to choose panels with a higher rated output, however there’s more to it than just the panel’s power rating alone. The amount of space available on your roof, particularly on the prime north-facing section, is also important. Fewer panels can also mean a quicker installation, so you really need to compare prices for whole systems, rather than just the panels.

How much do solar panels cost?

In terms of a solar panel buying guide, the cost of a solar PV system depends on a range of variables including the quality of the components and the size of the system. In 2013, The Alternative Energy Association (ATA) reported that the average overall cost of a fully installed 2.0kw system (before discounts and rebates) was around $4400. However, larger systems can cost more, and the price can also fluctuate year-on-year.

In terms of solar panel efficiency, it is simply a measure of working out the panels’ electricity output (in watts) compared to its surface area. Generally, the higher the efficiency the more power you can get from a certain roof area, however if you have plenty of roof space, it might be more economical to buy cheaper, less efficient panels and just use more of them.

It’s also worth noting that although solar panels are meant to sit in direct sunlight, they actually become less efficient as they get warmer due to the photovoltaic effect. So sometimes you’ll get less power from your panels on a very hot day compared to a mild day. Most ratings are based on standard (25°C panel temperature) conditions, and some panels have better ‘temperature tolerance’ than others, so if you live in a very hot climate, look for those that have a lower ‘temperature coefficient’.

Why types of solar incentives are available?

Something to consider when buying solar panels is that there are two types of incentives available to help you pay off your solar PV system, with the first being via small-scale technology certificates (STC’s). With the federal government’s Solar Credits Scheme, households that are eligible can receive money for STC’s that are created by their PV systems. While the government has set a price of $40 per STC sold, the price you get will vary on how you choose to sell them.

The easiest and probably most common option is to allow the installer to sell your STC’s on your behalf. This can then be applied as a discount on your installation costs. The upside is that all the paperwork is taken care of for you, the downside is that you’ll get less money per STC (often around $30).

The second option is to sell the STC’s yourself, which involves fees, applications and paperwork! It can also take a lot more time – you may not receive funds until months after installation, however generally you can get a better price per STC.

What about feed-in tariffs (FiT’s)?

Another thing to consider when buying solar panels is what sort of FiT’s you might quality for. A FiT is the rate that you are paid for electricity that grid-connected panels contribute to your area’s local network. There are two types – net and gross. Almost all FiT’s in Australia are net, which means a household is only paid if surplus electricity is fed back into the grid after domestic use is subtracted.

Gross FiT’s that offer tariffs regardless of the domestic electricity consumption involved still exist for some previously fitted systems, however the rates around Australia have plummeted over the past few years.

Also, in some areas, newly installed solar PVC systems no longer quality for FiT’s at all, although many energy companies will offer voluntary FiT’s instead. Check with your energy supplier or the appropriate regulatory authority in your state for more details.

Not sure if you should invest in solar panels? Contact the experts at Peak Voltage today for more advice. Call (07) 3272 7325.