PV solar panel Melbourne efficiency benchmark raised again

China has made news quite a lot this year in regards to the Australian solar market. First, there was the dumping inquest into their often cheaper panels, which was ironically dumped itself. Then there was the Asian giant’s announcement that it had well exceeded its set renewables target by a massive 40%, which was great news for Australian contractors in the area.

Not content with two big stories, China’s – and indeed the world’s largest – solar panel provider, TrinaSolar, has gotten in on the act with the announcement of the most efficient panel ever. TrinaSolar’s new range of silicon cell panels has moved the benchmark from 20.76% to 21.25% efficiency, following on from the company setting the previous record almost a year ago.

Whilst a jump of 0.49% may not seem to be that noteworthy, it’s important to keep in mind that the size of the cell tested was a tiny 150mm². When this is multiplied in a larger panel of single cells, this accounts for a massive jump in efficiency for a larger solar panel. Even more importantly, the cell that was tested was a p-type cell. What is a p-type cell, you ask?

p-type cells and n-type cells

Up until recently, the solar market has been the sole domain of p-type cells. These silicon cells are comprised of an atom with only three valence electrons (exterior bonding agents), often caused by “doping” the atom with phosphorous or arsenic. This uneven number forms “holes”, which allow the electrons to “wander” around the lattice, carrying currents. The “p” stands for positive, due to the missing electron, however the atom will remain neutral in charge.

n-type cells, whilst not necessarily new technology by any means, have been heralded as the next big thing in solar technology. Where p-type cells are missing an electron, an n-type cell will be doped with boron, creating an additional valence electron. This creates a cell which is negative in charge, and is generally more efficient than its p-type counterpart – up to 22% in some cases.

n-type cells are also less susceptible to cell degradation caused by heat or light, something which haunts p-type cells after an extended period of time. n-type cells are also less sensitive than p-type cells towards metallic impurities, owing to the difference in metals used. This makes n-type cells ideal for use as a solar energy conductor.

So why aren’t we all using n-type cells?

Like everything else, the better an object is at its purpose, the higher the price tag that comes attached. A p-type silicon wafer (not to be confused with a solar cell) roughly comes onto the market at AUD $1.49, whilst a n-type wafer will cost on average $1.79, when converted from USD. Therefore, p-type cells have always been more affordable for companies to produce.

To put this news in an even greater light, solar cell experts were doubtful that p-type cells would ever break the >20% efficiency mark. This was broken last year by TrinaSolar, as previously mentioned, with research and assistance provided by the Australian National University. So while n-type cells are definitely the future, experts predict that, by 2025, there will be a rough 60/40% mixture of p-type and n-type cells available on the market.

Given all of this, the fact that p-type silicon wafers are almost matching n-type wafers for efficiency spells great news, and the reason why this announcement has been well received. If the industry can continue to increase the efficiency of both by the 2025 marker, it will make solar panels justifiably the most affordable and efficient form of energy.

We hope you enjoyed the mini science lesson in this article. If you’re struggling to get your head around the numbers, don’t worry, the team at Think Solar is here to help. We share a considerable amount of experience across our team, and can use our expertise to get you the very best, most economical PV panel system for your needs.