Solar panels are unique as a form of electricity generation. Every other system converts mechanical energy into electricity, whereas solar panels do it directly from photons.
Take fossil fuel power plants, for instance. These burn coal or natural gas to heat water to produce steam which then drives a rotating turbine that contains a magnet to generate electricity. Electricity then travels along wires to customers who use it to power everything from their lightbulbs to electric vehicles.
Hydroelectric is no different. It uses rushing water to turn turbines. Nuclear is the same as well. Decaying nuclear material heats water to produce steam to turn turbines.
Solar, however, departs from all these energy-generating methods. It collects photons directly from sunlight and then releases part of their energy as electrons to form a circuit. These circuits can then hook up to the grid, providing the potential difference (voltage) to supply to consumers.
Progress
To consumers, solar panels look roughly the same as they did ten years ago. They’re square blue panels with around 72 cells glued to a backing plate. However, the price of the technology has come down substantially in that time. By some estimates, the cost of the panels themselves is around 80 percent lower than it was in 2010.
This is happening because of improvements in the supply chain and manufacturing technology. Firms are “learning” how to produce solar panels at scale which is bringing down the cost of individual units.
Unfortunately, the cost of installing solar panels hasn’t dropped quite as much for homeowners. That’s because the solar array itself is only a fraction of the total installation cost. Labor prices are pretty much what they were a decade ago, perhaps a little more.
However, solar installations at scale are benefiting. When power companies set up a large array, the relative cost of labor compared to panels goes down. That’s why more and more companies are setting up enormous solar farms in the desert to take advantage of incoming energy from the sun. They can now do it at low cost – much less than before, making it far more economical.
Manufacturing costs have come down partly because of the declining price of silicon. The material used to cost around $400 per kilogram. However, today, you can get a kilogram for around $10. Since silicon comprises around 15 percent of the total manufactured cost of solar panels, this collapse is helping to drive down prices significantly.
Diamond Wires
We’re also seeing the introduction of ultra-thin diamond wires. These run throughout the silicon in PV cells and reduce the amount of the material manufacturers must use even further.
Cell thickness may also be about to change. Historically, cells were around 180 microns in diameter. When engineers tried to make thinner cells to save materials, it led to cracking and shorter panel life.
However, diamond wires allow for thinner wafers, reducing the cost per watt output of solar panels by around 1.5 cents per 10 microns – a substantial effect.
Energy Conversion
Cell energy conversion is also improving – that is, the efficiency with which panels take solar energy and convert it into electricity. Historically, this efficiency was around 15 percent. Solar panels would only convert a small amount of the sun’s energy for electricity, with the rest of it going to waste. However, with improving technologies, that’s all changing. According to industry insiders, solar panel efficiency has risen by around 0.5 percent per year so that, today, it is common to find solar panels with efficiencies in the 20 – 22 percent range.
New Materials
Researchers believe that even higher efficiencies may eventually become possible. New material technologies and changes in paradigms may allow solar panels to convert as much as 50 percent of the sun’s energy into electricity. If this happens, it will vastly reduce the surface area required for solar arrays.
Experts believe that efficiency gains are likely to come in waves. Currently, we’re heading towards the tail-end of what current photovoltaic technology can do, but many new paradigms lie just around the corner. If China continues to develop its industry at breakneck speed, we may see new types of solar panel technology emerging over the next five to ten years. These may offer innovations such as PERC technology which essentially reflects previously unused light back into the cell for a second attempt at conversion.
PERC is a complicated technology to manufacture. However, the same was said of silicon panels in the early days (one of the reasons why companies made so few in the 1970s and 1980s). But costs are likely to come down, meaning that with PERC, the industry could achieve efficiency of more than 23 percent.
Bi-Facial Panels
Data suggests that PERC will be able to improve the efficiency of roof solar panels, but bi-facial panels may improve it considerably. The idea here is to allow panels to capture sunlight on both sides. Instead of having a backsheet, you essentially manufacture two PV arrays back to back.
The trick here is to use clear back sheets for the junction boxes. Light from underneath also interacts with the panel, increasing overall efficiency.
Of course, the challenge with this method is to leave space underneath the panel so that light can reflect back up. This means building taller structures and placing panels above reflective ground, not ground that absorbs light. Applications in the desert seem feasible, but there may be difficulties elsewhere.
The gains from the bifacial approach could be substantial. Some experts believe that it may allow solar panels to capture 5 to 20 percent more energy from incoming light.
Increases In Cell Size
We’re also seeing increases in cell size. In the past, they were 156 mm, but now there are plans to increase them to 166 mm and beyond. The larger the cell, the more efficient it becomes because there is less non-PV supporting structure.
Unfortunately, growing cell size is going to make panel backward compatibility more challenging. Unlike in the past, it won’t be possible to simply fit new cells to a panel and reuse the existing material. Instead, engineers will need to actually redesign the backing plate and start from scratch.
How Does This Affect The Environment?
The solar industry is all about steady, gradual incremental improvements. While improvements in technology on the order of 1 percent per year doesn’t sound like much, it makes a tremendous difference over the long term. Over 35 years, solar panels could become twice as good as they are today.
The environmental impacts of these improvements are considerable. Currently, experts estimate that the world will require giant solar arrays that cover most of the desert to meet its electricity needs. However, these predictions don’t take into account the fact that solar panels are becoming more efficient. A double of efficiency halves the area required for solar collection.
There is also the fact that solar panels are using less silicon than before. Extraction silicon is an energy-intensive process and it is costly in terms of CO2 to ship it around the planet. However, once solar panels become thinner and lightweight, these concerns will slowly fade away. In the future, it may be possible to build a solar panel with only trace quantities of silicon and other difficult-to-mine materials.
For homeowners, the performance changes probably won’t be that substantial. Solar arrays fitted to the roof already provide enough energy for all their needs. However, it is going to increase mains electricity supply options. It will become easier than it has ever been before to switch over to green tariffs and stop relying on conventional energy generation.
The biggest change will be in the price. Gross cost per watt continues to fall. In 2016, it was $3.57 on average. By 2017, it was just $3.17 and by the second half of 2020, it fell to $2.81, despite the issues thrown up by the pandemic.
Solar panel prices follow Swanson’s Law. This says that solar prices fall by around 20 percent for each doubling in global manufacturing capacity. As the price comes down, it encourages more people to enter the market, creating the demand to expand production and so on.
In a sense, solar panel technology isn’t all that different from conventional computer technology. Over time, prices come down and manufacturers are able to ship their goods to consumers at far lower cost.
If you’re in the market for solar panels, you’ll want to compare all the equipment installation options in your area. If you go around and get multiple quotes, you’re much more likely to receive a discount – often up to 10 percent.
When choosing solar panels for a home, consider the dimensions we’ve discussed here. Consider not only price, but also efficiency and how this could help you bring the cost of your system down. Quality installers should be able to explain to you why a particular setup of a given size works best.
How much you spend on a solar electric system depends very much on the total installed size of the solar panels themselves. Cost savings over the long-term can be considerable – and great for the environment too.
