Welcome to the April 2016 edition of the Direct Energy Buzz! This month, we’re going to cover innovations and new materials that potentially could change travel, solar power, and future computing power. And all of these cool things are developing because of what we’re learning about the secret lives of electrons. It seems that once they get into certain substances under certain circumstances, these subatomic particles behave in interesting and useful ways.
Solar Power to Dye For!
Israeli company 3G Solar Photovoltaics has devised a powerful dye solar cell technology that has the potential to do away with indoor consumer electronic and device chargers that use batteries. The cells get their power from either direct or indirect lighting.
A dye solar cell is a thin-film solar cell that sandwiches an organic molecular dye material between positive and negative plates. Light strikes the dye layer and has its electrons excited by sunlight, like the chlorophyll in green leaves. The dye acts like the electrolyte in an electrochemical battery (like a lemon battery) by allowing the electrons to pass through it while keeping the positive and negative poles isolated from each other.
Until recently, the technology faced the problem of developing a stable dye material. These new little solar cells now have a lifetime of 10 years and can put out enough energy to power up wireless computer peripherals, watches, surveillance cameras — which could lead to an expansion into Internet of Things (IoT) gadgets.
What’s Happening with Tesla?
Tesla Motors may have a just launched its most anticipated electric car, the affordable $35,000 Tesla Model 3, but only a few weeks prior to that announcement, Tesla quietly ended production of its 10 kilowatt-hour Powerwall. The Powerwall was designed to be Tesla’s line of residential backup batteries. Though announced last year to great fanfare – especially for the 7 kWh version – none of Tesla’s batteries were ever released in the US.
In fact, the company never even produced the 10 kWh model at all. The 10 kWh Powerwall was slated to cost $3,500 and offer 500 charging cycles, but critics made the case against it with cheaper deep-cycling lead acid batteries that come with financing. For homes with solar arrays hoping to sell their excess to utilities, the expensive Powerwall made little sense because a home owner would sell their surplus supply at night — which is when electricity rates are far lower.
Meanwhile, new data on the potential number of roof top solar arrays could provide 1,118 gigawatts (GW) of capacity or about 39% of national electricity sales. The Renewable Energy Laboratory (NREL) recent research study, entitled Rooftop Solar Photovoltaic Technical Potential in the United States: A Detailed Assessment, used light detection and ranging (LiDAR) data for 128 cities nationwide. The study showed that 83% of existing small urban buildings were suitable for solar arrays.
While only 26% of a building’s rooftop area was suitable for development, there are plenty of small building rooftops that could accommodate up to 731 GW of PV capacity. A small building is one with a footprint smaller than 5,000 sq ft (for example, a 70’ x 70’ single story structure). Annually, rooftop solar has the potential to generate 1,432 terawatt-hours (tWh).
Maybe Tesla will re-consider its big Powerwall battery in the future.
Could Dirac Electrons Change Computing?
A regular, run-of-the-mill computer circuit board is designed with one big headache in mind: heat. Heat in a circuit comes from electrical resistance as electrons rush through metal wires or printed circuit board tracings. The more power you push through a circuit, the more heat builds up from resistance. So far, conventional electronics are delivering about as much speed performance as can be squeezed from the materials that make up their boards.
New materials show that there’s still plenty of room for improvement.
Graphene is a one-atom-thick sheet of carbon atoms bonded together in lattice. It’s the lightest material known, it’s 100-300 times stronger than steel, and it’s hyper-conductive. So conductive that the electrons in graphene are governed by the Dirac equation. Dirac electrons are named for Paul Adrien Maurice Dirac, a British theoretical physicist and one of the original developers of quantum physics theory.
Dirac electrons do interesting things. In the graphene lattice, the electrons act as if they have no mass. They behave like photons in that they move at the same velocity and cannot stop. However, they can be manipulated using electromagnetic fields. That means Dirac electrons can zip about in the right kind of material like nobody’s business. If you’re looking to make circuitry for faster computers using Dirac electrons, then you need to find materials that also have these electrons in them.
And electronics manufacturers have been racing to do just that. Dirac electrons have been found in several metals such as copper-doped bismuth selenide. But recently, physicists at the U.S. Department of Energy’s Ames Laboratory discovered a metal known as PtSn4 (platinum and tin) with a unique electronic structure that may someday lead to energy-efficient computers with increased processor speeds and data storage.
PtSn4 is ultra-magnetoresistive. Resistance arising from the magnetic field —magnetoresistance — is used in contexts like writing data in hard discs. Exposing a non-magnetic metal to a magnetic field typically increases its resistance and reduces the amount of electric current that is able to pass through it.
BUT PtSn4 is what’s called a topological metal. These metals have certain deformations where magnetic fields boost electron conductivity. Scientists have not only discovered a high density of “boosted” conduction electrons, but the metal also has places (nodes) where Dirac electrons can arc from one place to the next, resembling the same sort of thing that happens in graphene.
What does this mean to you as an average energy consumer? This kind of technology then could translate into faster processing, faster memory, and faster read/write storage using far less power than today’s thinnest laptop. And all without having your machine heating up when you’re using it.