Sep 17 2019

Indoor Solar Cells

Sometimes technology is developed for a specific function. At other times, however, technology is developed simply because it is possible, and then uses are found for the technology later. Most often, however, it seems that technology is developed with some specific application in mind, but once it exists out in the world many new functions are developed. In fact the “killer app” may have nothing to do with the original purpose. This is partly why it is so difficult to predict future technology, because it is impossible to replicate the effects of a massive marketplace.

This is what I was thinking when I read about a somewhat new technology – indoor solar cells. This is actually not totally new, it’s basically organic solar cells. However, the solar cells have been optimized for the spectrum of light typical in indoor environments. There are, in fact, already indoor solar cell products on the market, but they are basically just regular solar cells sized for indoor applications. What’s innovative about these new indoor solar cells is their greater efficiency in indoor environments – the researchers claim a 26.1% efficiency. Further:

“The organic solar cell delivered a high voltage of above 1 V for more than 1000 hours in ambient light that varied between 200 and 1000 lux. The larger solar cell still maintained an energy efficiency of 23%.”

That’s pretty interesting, but not surprising. We are still on the steep part of the curve when it comes to solar cell development. I reviewed the technology recently – there are basically three types. Silicon-based cells are the ones currently dominating the market. Thin film, like perovskite, are being developed and promise to be better and cheaper, but there are still some technical hurdles to overcome. They are not yet stable for long term use, for example.

There is also organic solar cells. Organic may ultimately be the future (again, it’s hard to say). Organic cells exist and are in use. They are the cheapest to make, are thin and flexible, but they are not as efficient as silicon solar cells (11% for organic vs 26% for silicon). The fact that the current organic solar cells are claiming 23-26% efficiency is impressive, but I suspect this is because the overall energy production is so low. They would not be as efficient in sunlight.

Of what use are such indoor solar cells? Obviously they would not be used as an energy source to run your home. They would mostly just be capturing light you are producing with lightbulbs, and perhaps some light filtering in through windows and skylights. The idea is that these small flexible solar cells could power small devices that only need a trickle of energy. The advertised application is for the coming “internet of things” (IoT).

The IoT is the idea that everyday devices could be networked together through the internet to make them smart. For appliances that already have electricity, like your refrigerator, this is easy. Just put in a computer chip with wireless capability and you can communicate with your refrigerator over your smart phone. It can tell you that you are out of milk so you can pick some up on the way home, for example. Your appliances can also talk to each other. One application of this is regulating your use of electricity, to minimize peak demand, for example.

But here is where the chaos and creativity of the marketplace comes in. I suspect that the most impactful applications of the IoT are ones that no one has thought of yet. The ultimate killer applications may be completely different than the ones that were imagined when the technology was developed. The same is likely true of small flexible indoor solar cells. They can help the IoT by adding power to devices that normally are not powered. But once you can do that, connecting them to the IoT is just one application, and it may not be the most useful.

Essentially what this technology means is that it is cheap and easy to add about 1 volt of continuous power to anything in ambient light. The marketplace will not explode with ideas, testing them out, and eventually the best ones will emerge. How this will transform our lives, if at all, remains to be seen.

I can riff on some ideas of possible applications. How about a small sensor you insert into a potted plant, and then it will tell you when it needs to be watered. You don’t have to check that mouse trap in the basement, it will tell you when it has been activated. Your mailbox can tell you when it contains mail (your physical mailbox, not your e-mail). And perhaps someone more clever than me can think of applications for smart clothing. Essentially you can put a sensor anywhere there is ambient light and it can communicate to you through your smart phone.

Of course this might become annoying – getting constant updates from your house about every slight development. It may contribute to the technological noise with which we surround ourselves. Ultimately what we need is a way to close the loop – to have the objects in our lives not just notice a problem but fix it. A robot, of course, would be the most obvious solution – they could be in communication with everything in your house and attend to all the little details as they crop up. But this does not have to be one humanoid robot. The house itself can have multiple robotic appendages for various applications – like a Roomba, but for other applications as well.

Eventually we may live in a world where everything is alive with technology. Already I notice that I expect to be able to interact with things that previously you could not interact with. I am sure most people have tried to use a screen as a touch screen that was not a touch screen. After living with Tivo, I noticed that my instinct was to be able to pause and rewind everything, even live radio. Why doesn’t everything obey my commands? It’s amazing how quickly you get used to that functionality. Now I have a Google Home, so I can just shout commands into the air and my magical device obeys.

Imagine what children growing up in this world will be like. This is not in any way a criticism – it’s just an observation about how quickly we adapt to our surroundings. We are creating the expectation that we can interact with and command all the things in our environment, and the number of things this applies to is likely to dramatically increase. This kind of technology, the ability to distribute power to essentially anything, will make that easier. Everything will be “smart.”

Add to this the increasing use of virtual reality. In virtual reality you really can interact, theoretically, with everything. The world itself obeys your commands, and this too will create certain expectations. We may become frustrated with the meat world, and its stubbornness in not obeying our every whim and gesture. But of course we can fix that – we can make our physical world more and more like a virtual world.

While there will be many advantages to all this tech, and it will be fun if nothing else, I do wonder how crippling it will be also. Already I am dependent on GPS to get where I am going. I haven’t navigated by map in over a decade. I don’t remember anyone’s phone number – they are in my address book. I just click on their name or picture. This is not necessarily a bad thing (until the next big CME hits), but it is interesting. People don’t know how to ride horses either, or churn butter. Our skills adapt to the technology, and we become dependent on the combination of those two things.

But I suspect the adaptation works both ways. That is, ultimately, our greatest strength as a species.

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