When you think of renewable energy, what comes to mind? We’d venture to guess that wind and solar are probably near the top of the list. And yes, wind and solar are great as long as the winds are favorable and the sun is shining. But what about all those short and bleak winter days? Rainy days? Night time?
Unfavorable conditions mean that storage is an important part of any viable solution that uses renewable energy. Either the energy itself has to be stored, or else the means to produce the energy on demand must be stored.
One possible answer has been right under our noses all along — air. Regular old ambient air can be cooled and compressed into a liquid, stored in tanks, and then reheated to its gaseous state to do work.
This technology is called Cryogenic Energy Storage (CES) or Liquid Air Energy storage (LAES). It’s a fairly new energy scheme that was first developed a decade ago by UK inventor Peter Dearman as a car engine. More recently, the technology has been re-imagined as power grid storage.
UK utility Highview Power have adopted the technology and are putting it to the test all over the world. They have just begun construction on the world’s largest liquid air battery plant, which will use off-peak energy to charge an ambient air liquifier, and then store the liquid air, re-gasifying it as needed to generate power via a turbine. The turbine will only be used to generate electricity during peak usage. By itself, the LAES process is not terribly efficient, but the system offsets this by capturing waste heat and cold from the process and reusing it. The biggest upside is that the only exhaust is plain, breathable air.
There appears to be no shortage of reasons to hate on wind farms. That’s especially the case if you live close by one, and as studies have shown, their general acceptance indeed grows with their distance. Whatever your favorite flavor of renewable energy might be, that’s at least something it has in common with nuclear or fossil power plants: not in my back yard. The difference is of course that it requires a lot more wind turbines to achieve the same output, therefore affecting a lot more back yards in total — in constantly increasing numbers globally.
Personally, as someone who encounters them occasionally from the distance, I find wind turbines mostly to be an eyesore, particularly in scenic mountainous landscapes. They can add a futuristic vibe to some otherwise boring flatlands. In other words, I can not judge the claims actual residents have on their impact on humans or the environment. So let’s leave opinions and emotions out of it and look at the facts and tech of one issue in particular: light pollution.
This might not be the first issue that comes to mind when thinking about wind farms. But wind turbines are tall enough to require warning lights for air traffic safety, and can be seen for miles, blinking away in the night sky. From a pure efficiency standpoint, this doesn’t seem reasonable, considering how often an aircraft is actually passing by on average. Most of the time, those lights simply blink for nothing, lighting up the countryside. Can we change this?
It’s no secret that fossil fuels are quickly becoming extinct. As technology charges ever forward, they are disappearing faster and faster. Many of our current dependencies on fossil fuels are associated with high-energy applications like transportation. Since it’s unlikely that global transportation will ever be in decline for any reason other than fuel shortage itself, it’s imperative that we find something that can replicate the high energy density of fossil fuels. Either that, or go back to the drawing board and change the entire scope of global transportation.
Energy, especially solar and wind, cannot be created all over the world. Traditionally, energy is created in situ and shipped to other places that need it. The proposed solutions for zero-carbon energy carriers—batteries and hydrogen—all have their weaknesses. Batteries are a fairly safe option, but their energy density is pretty poor. Hydrogen’s energy density is higher, but its flammability makes it dangerously volatile to store and transport.
Fuel cells are like batteries, sort of. Both use chemical reactions to produce electricity. The difference is that when a battery exhausts its reactants, it goes dead. In some cases, you can recharge it, but you typically get less energy back with each recharge. A fuel cell, on the other hand, will make electricity as long as you keep supplying fuel. What kind of fuel? Depends on the cell, but most often it is hydrogen or methanol.
Researchers at the University of Bath, Queen Mary University of London, and the Bristol Robotics Laboratory want to use a different fuel: urine. According to the researchers, that’s one resource we will never deplete. The fuel cell is a type of microbial fuel cell which is nothing new. The breakthrough is that the new cell is relatively inexpensive, using carbon cloth and titanium wire. Titanium isn’t usually something you think of as cheap, until you realize that conventional cells usually use platinum.
We humans are becoming more aware every day that we need to reduce our fossil fuel dependence and move to more renewable methods lest we make the earth a less-desirable place to live. The sun is here today, and it will be tomorrow, harness that energy is one solution. There are places that are commonly windy, we can harness that energy too. [Jonathan] and [Ellen] set out to harness that wind energy but not in the traditional wind-turbine way. Wind creates ocean waves and the pair set out to recover some of that wave energy. They built a proof of concept and they did it on a budget with a side of DIY-style, to boot!
The device consists of a raft, with magnets attached to a sheet metal ruler standing on end. As you would expect, this ruler is flexible and the mass of the magnets easily sways back and forth as waves pass. The magnets move through stationary wire coils and as they do, creating an electrical current in the coils. The output of the coils is AC, which is then rectified to pulsed DC using several diodes and smoothed even further by some capacitors. The two DC outputs are then connected in series to double the voltage to 5 with a max current of about 20mA.
For this experiment the generator powers a modified smoke alarm which keeps burglars away from a coral reef. But the team could see this powering lights on buoys or low-power sensors. What would you use it for?
Most of our energy comes from dead algae or dead ferns right now, and we all know that can’t continue forever. The future is by definition sustainable, and if you’re looking for a project to change the world for this year’s Hackaday Prize, you can’t do better than something to get the world off carbon-based fuels.
Building the machines that make sustainable energy possible or even just the tools that will let us use all that energy are just a few ideas that would make great entries for The Hackaday Prize. You could go another direction and build the tools that will build and maintain these devices, like figuring out a way to keep these batteries and generators out of the landfill. Any way you look at it, anything that actually matters would make a great entry to The Hackaday Prize.