Solar panels have been around for decades, but that doesn’t mean the technology isn’t evolving. How has solar power improved over the years? And what are the latest advancements in solar power? We’ll address several major ones here.
The original solar panels developed in the 1950s had 4 percent efficiency. The original mass-produced solar panels had only 2 percent efficiency rating. This means they converted less than a twentieth of the solar energy they absorbed into electricity. Efficiencies surpassed 10 percent by the 1960s. In the 1990s, it was theorized that solar panels couldn’t have an efficiency of greater than 30 percent. As of this writing, the world record in the lab is 26 percent. The best solar panels on the market regularly have efficiencies over 20 percent.
Twenty years ago, the only way that solar power could be considered flexible was because you could load up the panels and take them with you whereas the small hydroelectric dam had to stay where it was. Today, solar panels are truly flexible thanks to thin film technology. Thin film solar panels have a few weaknesses. They’re more prone to cracking than the single crystal solar panels that were the only option for decades. They aren’t as efficient as traditional solar panels. However, they are literally flexible.
Depending on the material and the underlying substrate, they can bend and even curve. This means you can glue them to the top of a curved RV instead of trying to build a supporting frame for them. They can lay against the curves of your boat or car, collecting solar power on the nearest available surface instead of having to find a place to set up the panels.
While solar panels have been evolving, so, too, have the other components of solar power systems. For example, rare earth minerals have become the backbone of the energy sector. Forget lugging around massive lead-acid batteries. You can use a variation of the energy-dense batteries in your smart phone in an inverter instead. The inverter will capture extra energy from the solar panels and store it like a battery, releasing it when the solar panels are no longer generating power. More importantly, these inverters can deliver power in a variety of ways. They can typically provide both alternating current (AC) and direct current (DC) power. You could run both the 12 volt appliances in your RV and the AC appliances that normally have to be plugged into a wall socket.
Micro-inverters are smaller versions of the inverter. They convert power for each solar panel before sending the energy downstream. This means the entire system is more efficient. Why? Traditional inverters convert all of the energy coming from every panel. The entire system ends up having an efficiency rating as low as the least efficient solar panel. With micro-inverters, every solar panel’s power is converted at its current efficiency rating, so the average energy efficiency of the entire system is improved. If you think a few percentage points don’t matter, recognized that this is equal to an extra half hour of sunlight or a few more minutes before your laptop computer dies.
Grid connections and connecting cables have standardized. However, inverters are being made to be literally plug-and-play with other devices. The latest generation of inverters allow you to plug your smart phone charging cable directly into the inverter connected to your solar panel array. A few models are smart enough to act as solar panel management systems, communicating with devices downstream to maximize power throughput while maximizing safety. The increasing intelligence in these devices has led to over-current, under-current, over-temperature and other built-in protections that go well beyond fuses that blow out when the current is too high.
One of the biggest breakthroughs in solar panels was the development of poly-crystalline panels. Instead of creating a single large silicon crystal cut to create a single solar panel cell, the solar panel is made from a number of joined smaller crystals. You can tell the difference by sight. The traditional solar panel cells are smooth and reflective like glass. The traditional solar panels are more efficient, too. Why then are polycrystalline solar panels a breakthrough? They’re much cheaper to make, and they’re only slightly less effective than the traditional style. On top of all of this, all solar panels are coming down in price due to advances in technology. Interestingly, the price for flexible solar panels because the cost of the flexible substrates is dropping so fast.
We may see solar panel prices come down if research into novel materials comes to fruition. For example, there is research into light-sensitive inks made from polymers. Print these onto flexible substrates, and the same processes that make T-shirts so cheap you can make them for an event and throw them away can now be used to mass produce solar panels. Or you could create cheap, flexible solar panels that could be integrated into backpacks, tents and banners. We need new materials because materials like cadmium, gallium and selenium commonly used in solar panels are not abundant, so they aren’t cheap. Furthermore, demand for these materials to make smart phones and other devices is causing their price to go up. A side benefit of polymer solar cells is that they’d be as recyclable as other plastics, though you can recycle rare earth metals.
What about Solar Concentrators?
There has been continued efforts with concentrated solar power or CSP since the 1950s. It is, after all, a variation of the passive solar heating systems used to generate environmentally friendly hot water.
The most spectacular version of this technology are the solar power towers or heliostats that use an array of mirrors to concentrate solar energy on the central column of a tower. The tower generally contains a liquid that is heated by the solar energy and used to run turbines. The benefits of concentrated solar power include how easy they are to integrate into the power gird and how much easier it is to store heat over electricity. In theory, they have higher potential efficiency levels, too. However, this technology is fraught with problems.
One of the problems with solar concentrators include the massive cost of industrial scale systems required to have the same efficiency as a solar panel on top of the average recreational vehicle. Another problem is environmental. The beams of concentrated sunlight aimed at the tower are literally scorching. These solar concentrators have a reputation for literally frying migratory birds flying through the area. This isn’t a problem with a large field of solar panels. At worst, migratory birds land thinking it is a lake before leaving again. This is why solar panels are the future of solar energy, not solar "power towers".