The Solar Panel That Generates Power At Night

Source: Medium, Will Lockett
Photo: American Public Power Association on Unsplash

A new type of solar panel is here and it could revolutionise the world.

Solar power is a revolutionary technology but it is damn flawed. Yes, it is one of the lowest carbon forms of energy, but it is inconsistent. All it takes is nightfall or a cloudy day to render them near useless. To solve this we are building enormous solar farms and giant grid-level batteries to store the excess energy and deliver a consistent output. However, the ecological impact of these projects is far-reaching and detrimental. Solar is still one of our most eco friendly energy source, but it is by no means perfect, and if we want to avoid a climate disaster we need to do better. But, a team from the University of New South Wales may have just invented a way to make solar exponentially better by building solar panels that produce useable energy in the shade and even at night! So, could this technology make solar the ultimate renewable energy?

Before we examine this new panel we need to understand the limitations of our current solar panels. You see, currently they can only convert just over 20% of visible light into power. This is why they produce virtually no energy at all on those dimmer days and don’t produce energy at night.

To compensate for this we build solar farms whose output in optimum conditions is far greater than the amount needed. We then store this energy excess in giant mega-watt-hour batteries that can then distribute it over long periods at lower power, giving us solar energy even when it is dark outside.

Annoyingly this means that for a solar farm to be functional, they need to be larger than necessary and have giant battery packs. This increases its carbon footprint as solar panels and batteries take a lot of carbon emissions to build. It also means greater habitat loss to solar farms and a lot of environmentally dubious mining that causes havoc with ecosystems and even human health.

Make no mistake, even with these enviromental penalties, solar is still far more ecologically friendly than fossil fuels. But if we could reduce the size of solar it could become, by far, the cleanest and most environmentally harmonious energy source.

As it happens, this is what the team at the University of New South Wales has been trying to do with a very novel approach.

Instead of focusing on efficiency, the Aussie team focused on using a different form of light to power their solar panels, infrared light. This enables them, in theory, to shrink the size of a solar farm and the grid battery. Let me explain.

You can’t see infrared light, but thermal night-vision goggles do. You see, every object gives off what is known as ‘black body radiation’. This basically describes how the hotter a thing is, the more intense and higher frequency light it emits. In our day-to-day environmental temperatures, everything gives off infrared light (light with frequency below the colour red) 24/7. This enables thermal night-vision goggles (which ‘sees’ in infrared) to picture the hot deer against their cold background in the image above, and is what the Aussie team uses to power their new-age solar panels. They repurposed the thermoradiative diode that the thermal night-vision goggles use create an image and instead use it to make power from infrared light.

So, these panels effectively take the ambient heat of the environment and turn it into energy. So when it is cloudy or nighttime, it still produces power.

So how can we use this unique technology?

Multilayer solar panels seem like an ideal application. This is where you have different layers of solar cells on top of each other that absorb different wavelengths of light. This way, you can increase overall efficiency by absorbing more light. If we are going to use infrared solar tech it makes sense for it to be used within a multilayer panel so that it can function off visible light and infrared.

This enables the panels to make more power during the day and continue to make power through the night. So, they are overall more efficient, energy-dense and more consistent than regular solar. This means we could build smaller solar farms with smaller grid batteries that still produce the same output as current solar farms.

The ecological and economic benefits of this are easy to see with few less mining required, less land use and lower overheads. This makes it attractive to businesses, investors and eco-warriors alike.

All of this sounds amazing, doesn’t it? But annoyingly, it doesn’t yet hold up to reality.

Sadly, this technology has one huge problem. Current experiments have infrared solar panels at 1.8% efficiency and only produce around 2.26 mW per square meter. That is about 0.00023% of the power an average solar panel makes per square meter.

However, according to the researchers, it should be possible to get efficiency high enough to produce 10% of the energy of a standard solar panel. So an optimized infrared panel could make around 100 W of power per square meter, which isn’t a lot. It is the equivalent energy it takes to power a desktop computer.

But this little trickle is still potentially beneficial as it is being produced practically 24/7. If a 10MW solar farm (10,000 square meters of solar panels) was equipped with the optimized infrared tech, it would make 1 MW from infrared in optimal conditions (such as an equatorial country that is always hot). The average US home electricity power draw is 1.2 kW, so this tech could power up to an additional 833 homes for every 10 MW solar farm, which is a sizeable increase in output.

So we can’t yet build these more eco-friendly compact solar farms. We have to wait for scientists to develop this technology to come close to its theoretical limit, which could take a long, long time.

But it isn’t just multilayer solar panels that could use this technology. We have plenty of machines that churn out ungodly amounts of infrared as they heat up. Take nuclear power, for example, you could use these solar panels to generate a lot of additional energy from the heat of the steam escaping the turbine, making nuclear way more efficient and reducing the need for massive cooling towers. Only 33% of nuclear energy is turned into electricity. The vast majority of the rest is lost as heat, but these panels capture this and generate energy. This means infrared panels could make nuclear power far more efficient too.

So night-vision-derived solar panels are coming. They will make solar more efficient and consistent, ultimately making solar more compact and eco-friendly. But it can also be used as a super-efficient way to scavenge energy from industrial processes or make nuclear power even more efficient. This revolutionary tech is only in its infancy, but it already feels like it is ready to revolutionise the world! We just have to hope the scientists behind this tech can develop it quick enough to make a difference.

https://medium.com/predict/the-solar-panel-that-generates-power-at-night