What do the National Science Foundation, Purdue University and INDOT all have in common? They are all working hand-in-hand on the next generation of sustainable, electrical roadways to make America’s, and the world’s, electric vehicle future a reality, and the future looks amazing.
Their efforts are coming together in an experimental road project on U.S. 52/U.S. 231 in West Lafayette, where INDOT and Purdue are currently working along a 0.25-mile segment of road to construct and test a system that will wirelessly power electric vehicles in real time, while traveling at highway speeds. The system is called dynamic wireless power transfer.
The DWPT system will use electrical coils embedded in the pavement to transfer energy via electromagnetic waves to a power receiver on a specially equipped electric test truck. The process uses the principle of electromagnetic induction, where electrical energy in the coils creates a magnetic field, which in turn creates, or “induces,” electrical energy in the specialized receiver of the test truck. The energy is then disbursed wherever the truck needs it, either to its electrical motors or to its high-voltage battery.
Surprisingly, this energy that’s buried under the pavement and capable of moving commercial trucks will have very little ability or opportunity to interact with anything else. The magnetic fields created by the DWPT system are “non-ionizing and time-varying”, which means they don’t interact with living tissue, and they won’t act like a big refrigerator magnet that pulls your hubcaps off when you drive over them. It also means the magnetic fields are short range, extending less than a foot above the pavement’s surface. Additionally, each coil can only be powered on when it senses the power receiver in the truck above it, shutting off immediately when it passes out of range, or before, as each loop will have a maximum transmission time of about 0.2 seconds.
Stationary wireless power transfer systems (cordless charging for a parked EV) are already being implemented in various ways. California’s Antelope Valley Transit Authority and Tel Aviv’s University Train Station have both installed these systems at bus stops so that electric buses can charge while commuters are getting on and off. Various companies are also currently developing roll-over wireless charging pads to make charging EVs hassle-free. The next step – the step that has the potential to make EV ownership the status quo – is making the system “dynamic,” wirelessly powering electric vehicles while they are cruising at highway speeds.
The importance of making wireless power transfer into a dynamic form cannot be understated, because doing so has the potential to eliminate or reduce real-world hurdles that make widespread implementation of electric vehicles such a challenge. One of the main reasons people will not consider purchasing an electric vehicle is “range anxiety.” Do they have enough battery power to go where they want to go? Will they need to stop for long periods to charge? Dynamic charging addresses both of these concerns. The DWPT system is intended to maintain the energy level of the battery, essentially delivering the energy needed to move the vehicle while it’s driving over the system, saving the battery’s stored energy for later. Imagine a future where such systems are installed along the interstates and highways. Range anxiety would be a thing of the past, along with stopping for gas.
Another common concern for the viability of EVs is the source materials for all the new, big batteries that would be needed — rare earth metals. With a widespread network of DWPT road systems, the need to make thousand-pound EV batteries with a range of 300 or 400 miles becomes unnecessary. By cutting the size of the battery, you also cut the cost of the vehicle and the reduced weight means efficiency will go up.
This version of reality may still be many years away. After all, this 0.25-mile stretch of US 52 is just the beginning. The challenge of implementing such systems throughout the state may seem difficult, if not impossible. However, conceptually, it’s feasible. If people have the desire to accomplish this, and if it is persistently implemented with a long-term strategy, then it will happen. But the desire needs to be there to make it happen. So, why should we be pushing for EVs anyway?
With ever-warmer summers and winters, and with climate change-related natural disasters almost constantly in the news, people are looking for ways to cut carbon emissions. Many local, state, and national entities are targeting the transportation sector to make carbon-cuts, and for good reason. According to the EPA’s data on 2021 emissions, transportation is the largest source of greenhouse gas pollution in the United States. Roadway transportation — i.e., cars, vans, pick-up trucks, and semi-trucks — accounts for 82% of all transportation sector carbon emissions, whereas rail, ship, and aircraft, combine for a total 13% of emissions.
Transitioning from internal combustion engines (“ICE vehicles”) to electrical vehicles (EVs) is a great way to cut carbon emissions, because EVs are far more efficient. This becomes obvious when comparing the “miles per gallon” (MPG) of an ICE vehicle with the “miles per gallon equivalent” (MPGe) of an EV. The key is understanding what is meant by “equivalent.” The constant is how much energy is used to go the given distance, whether the energy is from gasoline or electricity. So, whether it’s MPG or MPGe, it is calculated by finding how far the vehicle can go when using the same amount of energy, whether it’s 115,000 BTU in a gallon of gas or the electrical equivalent of 33.7 kWh. That gives us an apples-to-apples comparison, and when you compare them this way, EVs use far less energy to go the same distance. For example, a new Ford F-150 (ICE) gets about 23 MPG, but the new Ford F-150 Lightning (EV) gets about 68 MPGe. A Hyundai Kona (ICE) gets 33 MPG, but the same car as an EV gets 120 MPGe.
This is typical of most EVs — they can travel about three times as far than their ICE counterparts on the same amount of energy. This alone accounts for a large drop in greenhouse gas emissions, making EVs a good investment for our health and environment. Add to this the potential for reducing or eliminating carbon emissions from the electrical grid through the use of wind farms, solar panels, tidal generators, and the like, and electric vehicles hold the promise of transportation that could be carbon and pollution free.
There are of course other arguments to be made. The improved efficiencies of EVs mean cost savings. The deployment of new technology means new jobs. The reduction of fossil fuels means increased energy independence, as well as reduced waste, reduced environmental contamination and spills, and cleaner air and ground water.
There are a lot of good reasons for us to desire an EV-future, and the work by Purdue and INDOT will help make it viable. Looking back from a distant future, we may find out this was one of the most important quarter-mile, single-lane stretches of road INDOT has ever built.
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