Solar QuotesI get a lot of emails from people asking “Which is the most efficient solar panel on the market?”.
Last time I checked, the awesomely awesome Sanyo HIT 195DA3 laid claim to the most efficient panels in production at a whopping 20.5% module efficiency!
(And before you SunPower fans swamp me with emails – yes, I understand that this is including light coming into the back side of the panel, which is would require special mounting – see the pic below. On a typical roof, the Sunpower SPR-318E-WHT-D will be the most efficient at 19.5% module efficiency)
An example of Sanyo HIT solar panel mounting to maximise efficiency.
But whilst solar panel manufacturers like SunPower and Sanyo battle it out for the “most efficient panel” gong, the question we really need to ask is: “Is the most efficient panel the best option for your roof?”.
And the answer is, “Not Necessarily…”
Don’t get me wrong – here are the advantages of going with a super-efficient panel:
If the panel manufacturer can make a solar panel that is so efficient, they must know what they are doing! The quality of the panel should be excellent, and it should last a long time. A panel that has 18%+ module efficiency is highly unlikely to be made in a dodgy factory in China in an attempt to cash in on the Aussie Solar Boom.
The more efficient the panel, the smaller the panel needs to be to generate the same power. So you’ll be able to fit a bigger solar system on your roof.
And here are some reasons why the most efficient solar panel may not be the right choice for you:
If you make the most efficient solar panels on the planet, you are gonna charge a premium for them (I know I would)! So you will likely end up paying more cash for the same size of system. If your main priority is to get the most electricity from your panels for the least cash outlay, then the number you should probably be looking at is “$ per kWh per year”.
How to work out “$ per kWh per year”
1. Get a quote (or three) for the size of solar power system you are interested in.
2. Make sure you get an “estimated annual electricity output (kWh)” in writing from each supplier. (If they refuse then run, don’t walk to another supplier)
3. Divide the cost of the system (fully installed, with new metering and connected to the grid) by the kWh number provided.
e.g. if you are quoted for a 1.5kW system at $4500 out of pocket, which is estimated to produce 2409kWh per year, then you are paying $4500/2409 = $1.79 per kWh – in the first year.
This gives you a number that can help you compare costs, and can be useful, but this method also comes with a big flashing warning:
“This number will give you the best value system ONLY if you can be confident that the panels and inverter are going to last and that they will be installed well…”
Basically, if the deal seems too cheap to be true, it probably is… I personally wouldn’t go near a $499 1.5kW special with a barge pole.
To sort the cheap-and-nasties from the systems which are genuinely a good deal use the list of questions here.
About Finn PeacockI'm a Chartered Electrical Engineer, Solar and Energy Efficiency nut, dad, and founder of SolarQuotes.com.au. My last "real job" was working for the CSIRO in their renewable energy division.
Hi Finn
How do you respond to the suggestion that AC panels are the way of the future and all the DC panels, no matter if they are the ‘best of show’ are basically dinosaurs compared with the AC panels now becoming available?
Thanks for you consideration.
Hi Peter,
I think that AC Solar Panels are the way of the future for small (less than 20kW) installations.
However it is not the DC Solar Panels that will become obsolete for small installations, because an AC Solar Panel is simply a DC panel with a micro inverter attached. It is the sub 20kW centralised inverters that may become obsolete. I hope SMA is developing micro inverters!
The reason I think that larger installations will stay with DC panels for some time is that if you have an installation with thousands of micro inverters, the chances of an inverter failing increases proportionally with the amount of micro inverters installed. It is a lot cheaper to replace one inverter every few years than be replacing a few micro inverters every week!
Hello Finn.
Just now decipehring quotes for a 5kw system. In your article “How Important Is Efficiency When Choosing A Solar Panel?” do you mean “Cell efficiency” or Module efficiency? I’m looking at Suntellite 195w as a choice. Their specs show 17.3% cell efficiency and 14.5% module efficiency. Are these figures OK relative to other quite good panels?
Philip
Hi Philip,
I’m talking about module efficiency. I’ve updated the post to make it clearer! Thanks for the great question!
I’m not familiar with Suntellite panels – I can’t even find them on the CEC approved solar panel list. Do they go by another name? 14.5 module efficiency is about average for mono crystalline panels.
Hope That Helps,
Finn