Blog Post Wednesday 21 November 2018
Solar panel have become popular in Australia as they offer potential cost savings as well as an eco-friendly approach to energy generation. From how they work to panel size, installation and positioning, there’s a lot to wrap your head around. If you're thinking about getting solar panels, keep reading as we explain everything you need to know before choosing a solar photovoltaic (PV) system for your home.
The evolution of solar
Solar energy could have started as early as the 18th century, when Swiss scientist Horace-Benedict de Saussure created the world's first known solar collector. Featuring three layers of glass, the solar oven reached temperatures of 110 degree Celsius by harnessing the power of the sun.
Solar technology reached the next milestone in 1839, when French scientist Edmond Becquerel discovered the photovoltaic effect by placing an electrode in a conducive solution and exposing it to light. The electrode generated an electrical current when exposed to sunlight. Later attempts are creating a solar cell included Melvin Severy's attempts to patent solar cells in 1894 and American inventor Charles Fritts' selenium-based creations in around 1883. In 1888, Aleksandr Stoletov also successfully created working solar cells.
Solar cells moved well beyond the invention stage by 1953, when Bell Laboratories created the world's first silicon solar cells. Six years later, Hoffman Electronics created solar cells that were 10% efficient and introduced grid contracts. Throughout the '60s and '70s mass commercialisation still eluded the industry, but government policy encouraged more research and development in the late '70s.
By 1983, worldwide photovoltaic production hit 21.3 megawatts, jumping to 1,000 megawatts by 1999, even as advancements in photovoltaics and concentrated solar power continued to achieve to better technology and lower costs. By 2016, MIT researchers were creating super thin and flexible solar cells measuring just 1.3 microns in thickness yet generating more than 2,720 watts per pound.
Today, solar panels today deliver up to 22% energy efficiency, and high quality household systems could still be generating as much as 86% of their original output after 25 years, losing just 0.5% efficiency a year. New and exciting technologies like the “perovskite” solar cells could eventually replace silicon and further drive down production costs.
Latest technology in the solar sector
So solar has come in leaps and bounds, but what are some notable ways solar is used? Today, solar is used to recharge mobile phones on the go with products like solar window sockets. You can charge your phone at the office, in a cafe, or even on the plane. Solar technology is also used for portable solar cookers and solar powered laptops for those who like to cook or work on the go. Power up your camera with a solar camera strap, or keep your devices powered up with a solar backpack or solar power purse that generates electricity as you go. Solar energy is used to power air conditioners, billboards, shelters for the homeless, and even bike paths.
How does solar energy work?
Solar technology captures energy from sunlight and transforms it into electricity at your power plug. The system consists of an inverter as well as the solar panels.
How do solar panels work?
The process starts with sunlight hitting your solar panels, which leads to electrons being knocked around and moving around. Your panels are designed to capture these moving electrons and guide them to moving around in the same direction on a circuit. When this happens, electrical currents are formed. In a system with multiple panels (an array), the flow of electrons generates direct current (DC) electricity. An inverter converts the DC electricity to alternating current (AC) electricity so it can be used in your home or workplace.
Solar panels works best when they're pointing directly at the sun and without any shade, such as from trees. The sunny climate of Australia makes solar energy a viable one for many households and workplaces.
How is electricity generated?
Within the panel, the electrons are guided to move on a circuit to generate DC electricity, which is then converted into AC electricity for use.
What do solar inverters do?
The solar inverter is a vital part of the system as it converts the DC electricity into a usable AC electricity. Inverters are also vital for ground fault protection, system stats like voltage and current, energy production, and maximum power point tracking.
What happens when it's cloudy?
Believe it or not, solar systems can still generate electricity for your house or workplace when it's cloudy, rainy, or cold. Unsurprisingly, the amount of energy you can generate tends to be a lot lower than on sunny days. Using more advanced solar panels and inverters could reduce the impact of shade or cloudy days, and your installer could help you with this.
While you can't do anything about the weather, you could optimise higher output by ensuring your solar panels are free of shade and shadows from things like trees and buildings. You can also split your panels across different parts of your roof to have them facing different directions, which could also help with more output. Other options include bypass diodes, which could help to reduce the impact of partial shading.
What about excess electricity?
If you generate more power than you use, the electricity can be sent back to the grid and you get credited with a feed-in tariff (explained in detail below). If you have a battery system, you could store the electricity for use later.
How to choose a solar energy system
Choosing a solar energy system can be a complex process, fraught with many different elements to take into consideration. So, when you first get started it’s important to know the three main things which could be the key differentiating factor. Above all else, you’ll want to compare certifications, warranties, and the type of panels when choosing a solar panel system.
Solar systems last for decades and reputable manufacturers should be happy to provide you with a 25-year warranty. In addition, a warranty might be no good if the original installer is out of business, so make sure you go with an installer with a good track record.
Type of panels
You have three main options when it comes to type of panels, but monocrystalline and polycrystalline are the two most common ones, with thin film being the heavier and less efficient (though cheap) option.
It used to be that you had to choose the pricier monocrystalline if you had a small roof area, but as panel technology has leapt ahead, you can probably go with the slightly less efficient but more cost-effective polycrystalline without compromising too much on energy efficiency.
Since monocrystalline and polycrystalline solar panels are today so similar in terms of benefits, your choice might ultimately come down to personal preference and appearance. Monocrystalline solar panels are sleek and uniformly coloured and they have larger gaps between panels thanks to their curved design. On the other hand, polycrystalline panels tend to be colourful with smaller gaps between the cells and therefore have less wasted space.
The installation process
If you live in an area prone to cyclones or other extreme weather events like areas of Queensland, you might be required to have your panels installed in a specific way. For example, your solar panels' mounting systems will need to be certified.
As we explained above, the inverter helps convert DC into usable AC electricity. What's important to note about solar inverters is they're not all created equal. Some inverts are more efficient than others, so ask your installer about the efficiency level of your inverter.
Ask your family, friends, colleagues, and anyone else you know if they've had experience with going solar. Get their insights, tips, and advice on how to choose the right system, and see if they can recommend an installer to you. Reviews online can also be a good way to check the history of potential installers.
The cost of solar energy
Solar panel systems are fairly major outlays so you should start by having realistic expectations about the price. At the same time, keep in mind simply going with the most expensive installation won't necessarily meet your needs and what you're looking to achieve with a solar system. Get multiple quotes and talk to each installer about your requirements. Assess each quote on its own basis by looking at things like terms and conditions, background and reputation, options, repairs, and extra and indirect costs.
Consider your break-even point, which is your solar payback time or when your system recoups the original cost of installation. When work this out, consider factors such as cost of installation, how much you currently pay for electricity, your household electricity usage, the size of your solar system, and your weather. So while it could cost more to install a big system, you could generate more excess power to sell back to the grid and so shorten the time to breaking even.
Cost of installation or purchase
A quality solar panel system of around 3kW or 20 panels could cost you around $5,000 to $8,000 fully installed. A smaller 3kW system with around 12 panels could cost between $3,500 and $5,600, while a larger 10kW system with around 31 to 40 panels could cost between $9,900 and $15,000.
This covers the cost of the solar panels, the ‘mounting system’, installation, and the ‘balance of system’. The mountain system secures your solar panels to your roof and is therefore an essential element your solar panel system. The balance of system (or BOS) includes components like wires, cables, isolators, breakers, switches, and your inverter. The inverter could account for as much as 50% of the total cost of your system. Finally, installation or manual labour, which has to be carried out by a licensed electrician, is another component of the overall cost.
Under the Small-scale Renewable Energy Scheme, you could get rebates in the form of small-scale technology certificates (STCs). These help subsidise some of your purchase costs, but they're calculated on the basis of zones (system size in kW x zone rating x years = Number of STCs), so depending on where you live, you could be eligible for more or less STCs.
Cost of maintenance
As the owner, you're responsible for the maintenance of your solar system. According to experts, an annual inspection of your rooftop solar system could cost around $150. Added to this is the cost of cleaning your solar panels, which might average at $10 to $20 per panel. For a system with 10 panels, the annual maintenance outlay might be $330 (for $18 per panel), and for a 36-panel system the cost could be $789.
Additionally, the inverter might need to be replaced a few times throughout the life cycle of your solar panel system. Your inverter might come with a 5- to 15-year warranty (or a longer one). When an inverter fails, it doesn't slowly lose performance power like your solar panels. Instead, it might simply stop working. In that case, your whole solar panel system will go down.
If you have a micro-inverters - which are fitted to each panel - these could last up to 25 years and so won't need replacing for a long time. Additionally, one blown micro-inverter won't shut down your system unlike standard ones. Talk to your installer about your inverter options.
Selling your energy back into the grid
And as you're assessing the cost of the solar system, take into account the possibility of selling your energy back to the grid. This means you can get a credit against the power you draw from the grid when your panels aren't generating enough electricity to cover your needs. The rate at which excess power sent back to the grid is calculated by using the feed-in-tariff, which we explain below.
What's a feed-in-tariff?
Feed-in-tariffs could be part of what makes solar panels worth it for you. Australia's feed-in-tariff system is also known as the solar bonus scheme or solar buy-back scheme. Feed-in-tariffs are designed to encourage people to go solar by allowing them to sell excess electricity back to the grid. So the higher the feed-in tariff, the more money you get when you send unused electricity back to the grid.
How do feed-in tariffs work?
When your system generates excess power, it's sent to the grid and in effect sold to it. You get a feed-in tariff in exchange for this energy. The feed-in tariff is expressed in kilowatt hour (kWh) and varies per state and retailer.
How do feed-in tariffs differ by state or territory?
Feed-in tariffs differ by state or territory because the system is administered at the state/territory level. The government could set rules about feed-in-tariff rates, size of eligible systems, and types of systems.
Currently, only Victoria has set a minimum feed-in-tariff rate (providers can choose to use a time-varying rate instead) and other states and territories have mostly opted not to require a mandatory minimum rate. However, the NT has a buyback scheme through PowerWater and WA has two different programs through Western Power and Horizon Power. Regional Queensland customers are protected by a minimum tariff rate.
In addition to setting minimum feed-in tariff rates, the state/territory government could have limits on how big the system can be to be eligible. So for example a system exceeding 100 kW in Victoria is not eligible to sell its excess energy back to the grid. You might have different limits on size of systems depending on whether it's a single or three-phase system.
When it comes to solar, two types of metering systems exist in Australia: net and gross metering. Most new homes are on a net metering system and gross metering is no longer offered for new connections except in Darwin. However, the Darwin gross feed-in tariff scheme is similar to a net tariff one since the purchase rates are the same as the feed-in rates.
With a net metering system, the power generated by your solar system is directed to household use first. Only when you excess power does it get sent to the grid. With a gross metering system, all the electricity your system generates is sent to the grid and you're paid for every kilowatt hour your system generates. So the difference between the two types is significant.
Getting a solar system could well be worth it in the long run, but you should do the numbers to figure out how much you'll be likely to save. Before you start looking for an installer, you'll also want to find out more about the different types of solar panels and the likely costs. Beyond cost savings, your solar system could give you the satisfaction of knowing you're generating some of your energy from eco-friendly sources. Finding a competitive solar feed-in plan with a retailer should be part of your going-solar plan.