Solar panels as we know them today have been around for decades. In that time they have only gradually increased in performance and decreased in cost. Panels from the early days barely made any power at all, while costing thousands of dollars. These days, high-end commercial panels are routinely more than 20% efficient – just enough to make them a serious contender as a solution to the world’s energy problems.
But what does the future of solar look like? Will it be the same technology we know today, just improved upon? Perhaps it will be something completely different that no one has thought of yet.
In this article I want to look at some of the possibilities that the future will bring to solar technology. All or none of this could become a viable reality, but the truth likely lies somewhere in between.
Let’s start with the most obvious future improvement we are likely to see. As I mentioned above, solar panel efficiency on the market is peaking at 24%. So how far will solar efficiency go? The theoretical limit, physicists say, is about 95%, but as far as we know that level of efficiency is impossible to reach. Based on what I’ve read, the current practical limit seems to be 68% efficiency. Since experimental panels have edged over the 40% mark it may seem like there’s not much more left to improve. However, teasing out almost 70% efficiency is going to take many breakthroughs that we simply can’t guarantee will happen.
There’s a promising new technology that uses a layer of photoluminescent material. This material absorbs full-spectrum sunlight and then emits it again at a frequency that’s optimal for current PV panels. This increases the overall efficiency of the panel to 30%. If this works out, it means that in the short term 30% efficiency will become the new baseline. However, remember that these efficiency limits only apply to the photovoltaic effect. There may be additional ways to make use of the waste heat. Hopefully some geniuses will figure it out!
Speaking of geniuses, there may still be plenty of new discoveries to be made in the more esoteric arms of physics. Quantum science in particular may hold ways for us to tap far more electricity from sunlight than we think is possible at the moment. There are theories that plants make use of quantum effects when doing photosynthesis, so there could be something to it.
Every Surface is Solar
Right now there are two broad types of solar panel. Most solar panels that you see are made from solid silicon crystals. They provide the best efficiency, but are the most expensive. Then there’s thin-film solar technology. What makes this technology promising is that you can basically spray it onto any surface. This means that your car could be painted in photovoltaic material. The same goes for windows and perhaps entire buildings – new solar technologies are biased towards using materials that can simply be sprayed onto surfaces. Possibly, this means that existing surfaces such as the outside of buildings could be covered in these PV materials.
While these technologies tend to be less efficient than solid crystal cells, this is made up for both by how cheap they tend to be and how much surface they can be spread over. Don’t be surprised if every viable surface that gets sunlight is one day covered in PV material. This could even include your clothes!
Perovskite Solar Panels
One of these spray-on PV technologies that looks promising is known as “perovskite” solar technology. These use a special crystal structure and metal-halide composition to bring in a decent list of improvements over existing solar tech. They are cheap to produce and have incredible solar absorption powers. You could literally print it onto paper and have a viable solar panel. The material only has to be 500 nanometers thick in order to absorb the entire solar spectrum.
The technology has already been demonstrated experimentally. Now the mission is to create a fully printable, flexible, and cheap solar panel that will be 22% efficient, matching the best of what current PVs can do. Perovskite technology is set to have a huge impact in the short to medium term when it comes to the future of solar power.
Quantum Dots Solar Panels
One of the main reasons that traditional solar panels are so inefficient is that they can only convert power from certain frequencies of light. Since sunlight contains the full spectrum of wavelengths, it means plenty of your sunlight is being converted to heat and then lost.
One way to make a solar panel that’s sensitive to a much wider spectrum of light is by using quantum dots. These are nanoscale semiconductor particles. They’re already using them in LCD TVs to produce a much wider range of colors than has been possible before.
Quantum dots can be adjusted to match the whole spectrum of light from the sun; this makes a massive difference to efficiency numbers. Some estimates show that quantum dot panels could be as much as 70% efficient, which is close to the absolute efficiency limit known to the current laws of physics. An even more amazing feature of this technology is that it works at night!
OK, you might think I’m pulling your leg since the Sun is then on the opposite side of the planet, but it’s true. Quantum dots can be set to generate electricity from infrared and other invisible light wavelengths at night. There’s still plenty of light bouncing around, we just can’t see it. Obviously this is much less energetic, but it’s still a cool feature.
We’ll see perovskite panels come to market long before quantum dots, but there’s a good chance we’ll see them in a decade or so.
Solar Thermal Energy
There are other ways to use solar energy for electricity generation that does not rely on the photovoltaic effect. As a case in point, we have solar thermal energy. Here solar collectors concentrate the heat of the sun into a material such as salt, or more recently, sand. These materials absorb the heat and become incredibly hot themselves, but they hold on to much of that energy. This heat is then placed into a heat engine that makes electricity.
While this technology doesn’t really make sense for small home installations, it’s a proven method for large solar power plants. This method is between 30 and 40 percent efficient, which beats any commercial PV cell today. It also provides a way to store the energy until it is needed. That turns solar energy into a viable baseload energy provider. These materials are far safer and less expensive than battery storage.
Solar thermal energy technology is one to watch when it comes to grid-based, large-scale solar energy production. It won’t supplant photovoltaic technology entirely, but could dominate in this central energy production space.
Deserts Covered in Solar Panels
One of the most interesting proposals I have seen in recent times is one where the entire Sahara desert gets covered in solar panels. This might seem like a crazy thing to do, but it makes sense when you think about it.
Areas of the Earth like the Sahara get the most intense sunlight and it almost never rains. So putting panels there will give you a much better return on your investment than, say, setting it up in England. Of course, there’s still the matter of getting the energy where it has to go, but no one said such a project would be easy.
The really fascinating thing about this idea, however, is that researchers think it will affect the climate of the desert. By covering a significant part of the desert surface with solar-absorbing material, the conditions that make the Sahara a desert will begin to change. It will rain more and perhaps become a green oasis. Whether that’s good for the long-term prospects of both climate and solar power remains to be seen. However, isn’t it fascinating how large-scale solar projects can bring about climate change of a different sort? Expect that to become an increasing point of debate as time goes on.
Photobiological Solar Cells
Plants have had the entire history if life on Earth to evolve their solar power tricks. There are so many things we don’t understand when it comes to photosynthesis, but without it no animal life would exist at all. Using the biological ability to turn light into food and other forms of energy is something that scientists are working hard to perfect. So scientists are engineering better plants that could lead to better crops and more efficient plants.
A neat offshoot of this research is the creation of biological photovoltaics. In other words, you use plants to take in sunlight and then turn it into electricity. In a future where this technology is a success, we could use plant life to make electricity. It would be the ultimate solution for a world devastated by electricity generated through the destruction of the environment.
Virtual Solar Power Plants
You’ve probably heard of the “gig economy” and how services like Uber use the power of the internet to combine the resources of thousands and thousands of people into one big virtual organization. Now we have things like AirBnb, and every day it seems that new ways of exploiting the so-called “sharing” economy is entering the market.
A virtual power plant could be considered a version of this approach. It’s a cloud-based internet control system that monitors and interfaces with various power generation sources. These could be solar, wind, traditional steam turbines – it doesn’t really matter. The system combines all of these different power sources into a reliable energy supply just as a traditional power station would give. This means that people can set up small solar farms or other small generation systems and hook them into the virtual grid. They can sell power to the system with automated market processes handled by the cloud service.
There are already examples of these virtual stations in Europe, America, and Australia. Perhaps one day it will become a standard way to weave together all energy generation and use it in the most efficient and the cheapest way possible.
Solar Farms on the Sea
Most of Earth’s surface is covered in water, which is constantly sapping up solar energy and acting as a giant heat sink for the planet. Thanks to climate change, the oceans have been taking in more heat than ever; even if climate change were fixed today, the stored heat in Earth’s oceans could still mess up the climate for decades.
While there doesn’t seem to be all that much we can do about it, the ocean is the largest solar collector on Earth. So why not get in on some of that action and put floating solar farms on the ocean’s surface? Not only can this help intercept some of that heat, it would make energy cheap and abundant. It’s also possible to put power cables on the ocean floor to instantly pipe that power to where people need it. We are already putting wind power out in the ocean, so it seems sensible to also put solar power plants out there too. The future might see a large amount of power generation shift offshore with permanent floating solar farms.
Solar Farms in Space
Then there’s the other, infinite ocean of space. One far-out idea is to build solar farms in orbit, where they can get the strongest dose of unfiltered sunlight. Then we can beam the energy down to Earth’s surface as microwaves.
Beaming energy by microwave is far from a new idea. But if put into such a large-scale practice, it would mean animals that flew into the path of the beam might get fried, and air traffic would have to avoid those zones. Still, with a geosynchronous, tight satellite-to-ground beam, it might just be possible. I wouldn’t put too much money on this one though.
Bifacial Solar Panels
When it comes to solar panels, the total amount of area that generates power is very important. Bifacial solar panels double the amount of PV surface by generating power from both sides.
Today’s standard solar panels take in light from one direction and have an opaque backing material. With a bifacial panel light passes right through the panel. Any light that hasn’t been absorbed is then reflected off whatever is behind the panel and back into the PV. If the surface under the panel is highly-reflective this can mean as much as 30% more power from the same panel size!
Obviously, it matters where and how you install these, but there’s a good chance that bifacial panels will become the norm for ground installations and other suitable setups.
The Future is Solar
With the current state of solar efficiency, the rise of electric vehicles, and improvement in appliance energy consumption, solar power is looking more and more attractive every day. Unless someone cracks the problem of clean nuclear fusion, which is like having your own little sun, then tapping power from the biggest fusion reactor we know of is the way forward. Of that I have no doubt.