Solar Panel Efficiency

Most commercially available solar panels have efficiencies around 12-17%. Thin film panels mostly are at the lower end, with crystalline panels at the mid to high end. But what does a high efficiency rating actually mean? Does a high efficiency panel mean that your solar system is going to generate you more kWhs? Not necessarily, here’s why.

Polycrystaline solar cells

Polycrystaline solar cells

The panel’s efficiency rating is based on the amount of the sun’s energy that it can convert into electricity. On a clear day the sun dumps about 1000 Watts of energy per/m2 at sea level. If a panel has a 15% efficiency rating, it means that 15% of that energy is turned into electricity. So if the panel was 1m x 1m it would be 15% of 1000W or a 150W panel. These days, most panels are around 250W and have a larger surface area, more like 1.7m2.

So what happens if we have a high efficiency 250W panel of 20%? Basically the surface area gets smaller; a 250W panel at 20% efficiency has a surface area of 1.25m2. Both panels have the same output – 250W, but are different sizes. So in terms of the way a system with high efficiency panels performs, compared to one with lower efficiency panels, if all things considered are the same the output will be the same. In a 3kW system with 12 x 250W panels, the lower efficiency panels will just take up a larger area – 20.4m2 compared to 15m2.

When you are deciding on which solar panel to choose, there are a number of things to consider. A high efficiency panel can be a good option if you have a restricted roof area, but if you are looking at system performance there are other factors to take into account.

Green Energy Options offer a range of different solar panels including the Sunpower E20/327, which at 20% efficiency, has the highest efficiency of any commercially available panel. If you would like to advice on solar options for your property please give us a call on 1300 929 931 for a free consultation.

Solar panel orientation

Which is the best direction to point your solar panels?

It’s an interesting question and you would think the answer is pretty simple – NORTH.

In many cases you’d be right, a north facing solar array will generate more electricity than an array that faces east, west or south. In Geelong, putting panels on an east or west roof will normally result in a loss of around 15%, compared with a north facing array on a 30 degree pitch. Many people are surprised by how small this loss is and it certainly doesn’t rule out these options. It’s  recommended however to steer away from south facing panels where possible, where losses are in the range of 30-40% on a standard home’s roof pitch.

Solar panel oreintation

With the introduction of lower feed in tariff (FIT) rates for your solar electricity that’s exported to the grid, an interesting discussion about solar panel orientation has come about. Should we be facing our panels west?

Sure a north facing array generates more electricity than one that faces west, but it generates the peak of it’s generation for the home in the middle of the day. For the average working family that has a low electricity consumption during the day it could mean that a lot of the electricity generated is being exported to the grid at the current FIT rate of 8c/kWh. The theory is, that if you were to face your panels west, they would generate more electricity later in the day, when you are more likely to be using the power. In this case you would be able to offset the cost of buying electricity from the grid at the going rate (often over 30c/kWh), which is more valuable to you. This is true particularly in summer when solar production is higher and the daylight hours are longer extending into dinner times.

Another related argument for pointing panels west comes from a Renew Economy article where Adam McHugh, a lecturer in energy economics and energy policy at Murdoch University, where he suggests that pointing solar panels west, would correlate the systems output with times of peak demand on summer afternoons. On hot sunny days when everyone turns their air conditioners on, west facing solar panels would be producing electricity. West facing solar has the potential to compete with the distribution network and expensive peak generators by reducing the cost of supplying electricity particularly during peak demand events.

The orientation of your roof and available space may be the deciding factor in the end, but it’s good to know that there are normally a couple of options. A good solar installer will give you a comprehensive analysis of your solar systems production as part of your quote. This should show average daily kWh estimates broken down monthly and for the year based on your roofs orientation and pitch.

For more info on panel orientation or the potential of you roof give Green Energy Options a call on 1300 931 929.

Six Solar Tips

Six solar tips to consider when buying a solar power system

There’s a lot of information out there in solar la la land and if you are new to solar, it can be tricky to sort through and find the answers you need. I’ve put together a list of six solar tips to help give you a good start on things to consider when buying a solar power system. Here we go…

1. Find out who manufactures the solar panels and inverter.

Do your research. Does the brand have a good name? What have other people’s experiences been like? Some companies are reluctant to give you this information and some are using cheap rebranded or “lucky dragon” panels which have only been on the market a couple of years and substitution of lower grade materials is not unheard of. Choose an installer that is transparent about the components they use and stick with well-known brands that have an Australian office for warranty issues.

2. Make sure you’re happy with the installation company.

Who are they? Are they close to you? What have others said about their service? Are they members of any industry bodies Clean Energy Council (CEC), Australian Solar Council (ASC), Solar Energy Industries Association (SEIA) or the Alternate Technology Association (ATA)? There are a lot of solar installer reviews online if you want to find feedback. Also watch out for the hard sell sales tactics, steer away from anyone trying to get you to make your mind up on the spot.

3.      Don’t buy the cheapest solar system you can find.

Obviously price comes into the equation at some point when you are buying a solar system, but like anything, you get what you pay for. There are many ways to cut costs in a solar business, I could purchase the cheapest panels/inverters that I could find, I could squeeze my installers on the installation cost, buy cheaper isolators, cabling or other balance of system components, or I could skimp on the resources I put towards customer service and post installation backup. Either way, by compromising on the above things you may find you end up with a less than average solar system or less than average solar experience. You don’t have to buy the most expensive option to get a good system, but don’t buy the cheapest!

Ballarat Solar Installation

Ballarat Solar Installation

 4.      Don’t compromise on the inverter.

50% of all system failures have something to do with the inverter. There are heaps of cheap options out there now, often at less than half the cost of the good stuff. Our suggestion is, it’s not worth it, buy a good quality inverter – some examples include SMA, Aurora or Xantrex. If your panels are going to last 25 years+ you don’t want to have to replace an inverter every five years. There are also some fantastic micro-inverter options becoming available, these generally come with stronger warranty periods, better system monitoring and safety and performance benefits.

 5.      Take your warranty with a grain of salt.

Although warranties are an important aspect of buying a system  nearly all panels on the market have a 25 year performance guarantee, stating that the silicon will degrade at a certain rate over time, with the panel still producing a minimum of 80% of its initial output after 25yrs. Note that the panels also have a materials and workmanship warranty normally in the range of 5-10 years. Inverter warranties are normally between 5-10 years with some micro-inverters offering up to 25 years. Then there’s you installation warranty from the installer which usually is 2-5 years. The one thing to be aware of here is that the warranty is only as good as the company behind it, if they go into liquidation or are taken over by another business, you might find yourself left high and dry. Some big panel manufacturers and installation companies have gone bust or dropped out of the solar industry recently, so be careful. Our best advice is to read the fine print, stick with good quality components to minimise the need for warranty claims and go with a company that has a track record and you feel you can trust.

 6.      Size the system to cover your daytime usage.

In Victoria, the Feed in Tariff is now a minimum of 8 cents per kWh. The price you are paying for electricity is probably up around 30 cents kWh. This means you don’t want to oversize your system too much, as you won’t be paid very much for the excess power that you’re not using directly and exporting back to the grid. If you size your system right, you will get a better return on investment and quicker payback period. If you need some help here we can give you some advice. Note that there is currently a great niche for many businesses that use power during the day to capitalise on the benefits of solar power.

I hope the tips help. If you have any further questions, or are after some advice please feel free to give us a call on 1300 931 929.

Cheers Aaron.

Solar lighting up East Timor

Giving the gift of light

East Timor Solar

Green Energy Options is helping East Timorese Communities light up with Solar

East Timor is one of the poorest countries on earth. Many regions rely on candles or kerosene lamps for light and firewood for cooking. There is little electricity infrastructure and many communities are without electricity.

Green Energy Options teams up with the Alternate Technology Association’s (ATA), International Projects Group (IPG) to donate a solar panel to an East Timorese Community for each system that we sell here in Australia. The ATA, IPG has been operating in East Timor since 2001 and has helped to power more than 1000 homes, community centers and schools and hospitals.

By providing light and electricity to those in poverty, we are helping to increase education opportunities, grow job prospects and improve health issues like breathing in kerosene fumes.

For more information give us a call on 1300 931 929

Or visit

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