Being in the industry, we often hear about the breakthroughs being made in development stage solar power, and to be honest, it excites us nearly as much as energy storage. It was a shock to the industry when it was reported that panels were exceeding 20%, reaching up to 22.5%.
There have been a number of limitations placed on the industry in the past, that have affected R&D, one being a lack of investment (which has made strides recently) and one being the laws of physics. It looks like we are beginning to figure it out and work around both.
Previously it was thought that solar panels (or single junction silicon panels) weren’t capable of achieving more than an efficiency of 33.7%, due to a number of factors outside of our control. For example black mass radiation, simply occurs when radiation is absorbed and not converted for no apparent reason other than a material's inherent properties.
Recently a company called Alta Devices exceeded a 30% efficiency rating and is planning on hitting a 50% rating soon. It's important to recognise the huge gap between R&D solar and commercially available solar. For example, the best solar panel currently on top of Australian roofs most likely has an efficiency of 15%-17%. However, Such a system is still very capable of generating electricity for your home.
Alta achieved this feat by using thin film gallium arsenide panels which are much more efficient, and double the cost of your standard silicon panel. For now, these types of panels aren't ideal for most, given their exuberant costs. However, they give us an excellent idea of what to expect in the future.
These new super-efficient panels are employing a number of techniques to truly stretch the available energy within a photon by reflecting and recycling the momentum multiple times before ‘releasing’ it. So far simulations show that a 50% efficiency is possible and the company is hopeful.
People are wary of the costs of such technologies, but when there is a demand the invisible hand of the market will always help bring down production costs and increase supply. Solar power has always increased in efficiency and it looks like it will continue to do so for the foreseeable future.
Thin film arsenide panels are not the only technology in development which are aiming greatly improve our ability to harvest the sun’s energy. For example, quantum dot technology is able to split light waves into the visible spectrum and infrared, harvesting only concentrated wavelengths. Meaning that solar panels can be made to be transparent. This opens the doors for solar windows, sunroofs, and even smartphone screens.
On the other end of the spectrum, technologies which aim to bring down costs are also being heavily invested in. Perovskite panels have recently been shown to achieve 18% efficiency (higher than most standard silicon panels) at a cost ‘1000 times cheaper [than three-junction panels like Alta’s]’.
While 18% might not sound impressive after hearing about Alta’s plan for a 50% efficiency rating, perovskites have only been in development for just a couple of years, and efficiencies are continuing to increase. This is in stark contrast with silicon panels which took 20 years to achieve 20% efficiency ratings.
The sheer number of technologies in development which are hoping to be the next big thing in renewables are indicative of a bright future, one in which 50% efficiency ratings are a definite possibility.