We are familiar with generating power from the sun and wind, but the next generation of power could come from the dark and other surprising sources.
The future of power generation will include many devices in the home and office that power themselves — in whole or in part — using energy available from the environment. They will supplement the traditional electric grid, relieving it of the need to generate energy and making the entire system more resilient.
Recent advances in the field of energy capture have opened new doors in electric generation. Whether it’s from ambient light, the heat from machinery or electronics, or even the dark of night, new avenues are opening for sources of power.
Indoor Solar Cells
It doesn’t take the sun to power a photo-voltaic panel; ambient indoor light is being harnessed in the laboratory and could provide power to home appliances and lighting soon. Small-scale, organic solar cells can pick up light on multiple different wavelengths. It’s conceivable that a lightbulb could be partly self-powering, generating electricity from the light it emits in a second solar small solar cell on or near the bulb.
How it works: A light-absorbing layer made of materials can be tweaked to capture the energy from many wavelengths of available light — not just sunlight. Scientists have determined that a specific combination of these materials can absorb ambient indoor light to power LED bulbs.
Researchers at Linköping University recently developed a new form of organic solar cell that absorbs ambient indoor light at levels that can generate electricity. These organic solar cells are flexible, cheap, and easy to make in bulk. The technology is continuing to improve. It can currently provide more than one volt of electric output for more than 1,000 hours using ambient light. For example, the light in a room can power small devices. Considering how much of ambient indoor light is artificially produced, these solar cells are a promising new form of energy recapture.
Low-Light/Nocturnal Cells
Although we think of light as a source of energy, the darkness if full of energy, too. A new generation of small-scale energy production could come from the cooling of materials that collect heat during the day.
How it works: A dark material collects heat during the day and as it cools, which is known as “radiative cooling,” the surface of the material passes heat into the air as thermal radiation. This small change in temperature is a potential power source, generating enough electricity as the heat escapes from a can-sized surface to light an LED.
Until recently, there was no equivalent to a solar cell that would work during the dark hours of the night. Researchers at the University of California, Los Angeles, and Stanford University created a device from an aluminum can lid painted black connected to a small thermoelectric converter that can generate electricity using radiative cooling. Instead of collecting radiation, light, or heat, it creates electric current from the escaping heat that was stored during the day.
The cell can generate 25 megawatts per meter squared of electricity in low light or completely dark conditions.
Paramagnetic Energy Generation
The last innovation is a bit more difficult to understand. Paramagnetic energy generation uses small magnetic field changes that occur when a magnet is heated to output electricity. Heavy machinery that generates heat as it operates — and many smaller electronics, such as a computer — could capture waste heat and convert it into electricity. That energy could even power the machines that generated it, raising the bar on efficiency dramatically.
How it works: Paramagnetism is an unusual state that emerges when a magnet is warmed. It becomes less magnetic and, instead of creating a magnetic field, it produces paramagnons, an exotic low-power particle that can perform work if captured. The discovery of paramagnons led to a new methodology for designing thermoelectric semiconductors, things that convert heat into electricity.
“Because of this discovery, we should be able to make more electrical energy out of heat than we do today,” wrote Joseph Heremans, professor of mechanical and aerospace engineering and Ohio Eminent Scholar in Nanotechnology at The Ohio State University. “It’s something that, until now, nobody thought was possible.”
In September 2019, an international team of scientists found a potential method to capture heat and turn it into electricity. The breakthrough came from particles called paramagnons. While these particles aren’t magnets themselves, they carry magnetic flux. Particles are also waves in the weird world of sub-atomic physics and, because they are waves, paramagnons produce a change in state that we can use to generate power.
Normally, when a magnet is heated, it loses most of its magnetic properties, becoming paramagnetic. The research team investigated whether these paramagnetic particles could still produce enough flux to move electrons, which was assumed not to be possible. Parmagnets can push electrons long enough for them to be viable energy harvesting tools.
As this technology advances, the range of uses for collecting excess heat and generating an electric current is vast. We could use paramagnetism to generate electricity from the heat emitted from things like car exhaust, or industrial processes. Given how many different processes generate heat, as this technology is refined, its use will likely spread like wildfire.
Promise and Opportunity
Making new power sources widely available used to mean building centralized generation plants and stringing more electric lines. But the emergence of small power generators will change the traditional system. We’ll be able to power our homes and offices using locally generated power — so local that power utilities will have less to do.
Resilience, the core idea of sustainability, means that the system becomes less fragile as they add more flexibility. In the case of electric power, flexibility at “the edge” of the traditional power grid will transform our ability to live a modern life with less impact on the environment. These technologies are just beginning to emerge, but as scientists continue to explore, more and more paths to green power will be opened.
The future is looking bright.