In this first in a series of four Halloween-themed articles, Paul Martin explains why PV solar panels are great, but are best left off cars
We’ve all seen it: great new technologies with huge potential from a central promise to revolutionize what we do. However, each comes with a challenging list of problems that — when viewed objectively — relegate the technology to prototype form with limited commercial value. These problems could include available technology, cost, business model, and in some cases, the basic laws of physics.
However, these problems aren’t enough to stop hardy groups of individuals from continuing their development and promotion, fuelled by the promise of fulfilling those technologies’ potential.
New Mobility is no exception. In this short series of Halloween-themed articles, James Carter and Paul Martin analyze four technologies that display zombie characteristics.
Zombie Technology 1: Solar panels on cars
Zombie Technology 2: Hydrogen fuel cell cars
Zombie Technology 3: Wireless charging
Zombie Technology 4: E-roads
Park your car in the sun and never go to a gas station again! You don’t even need to plug it in!
The roof, hood and trunk lid are obvious places for solar panels. Some add them to the doors or have tilt-up panels that double as sun shields inside your windshield when you park. The panels collect sunlight and convert it into electricity to recharge your EV’s battery. The dream of driving directly on sunlight must be just around the corner, right?
Solar panels take energy to construct and manufacture. If you point them at the correct angle to the sun and keep them there, they will happily make electricity for you whenever the sun shines — for 20-to-30 years — paying back the energy they take to make many times over. But if you put them in the shade, cover them with snow, or orient them at the wrong angle with respect to the sun — such as, ahem, mounting them to the flat roof or hood of a car — they don’t do much except add weight and cost.
Doing some math on this is instructive. A 300W solar panel is about 1.5 square metres in area. Let’s say you managed to fit 1,000W (1 kW) worth of panels on your roof, hood and trunk lid (4.5 square metres worth for a large car). Assuming your car is never in the shade of a building or tree, an economical photovoltaic (PV) panel in Toronto could make on average about 1,000 kWh per year. That’s an average of about 2.74 kWh per day — enough to drive your car about 11 kilometres per day. Hurray! We have a viable idea, don’t we?
But what about the times when your car is parked in the shade? In a garage? Or let’s say your car wasn’t driven yesterday and the battery is already full? The panels are worthless in those cases.
Then there’s the fact that the sun shines longer and more brightly in summer than in winter. You get a few more kilometres during those long summer days, and almost none in the winter — when your range is most depressed by the need to heat your cabin and battery.
A small solar panel on your car roof might be of some use to run a fan to keep your interior cool during the heat of a summer day. But any more is basically (roof) window-dressing. If you have 1 kW worth of solar panels, it is far better to put them on the roof of your home or business where they can really earn a living. Not only will they make 20%-40% more energy because you’ll angle them properly toward the sun, they’ll also make electricity to charge your neighbour’s car when yours is full. Pair that with smart chargers for EVs at work, so EV drivers can choose to soak up cheap solar electricity when it’s available in excess, and you really have a good idea.
PV solar panels are great, just not on cars.
Zombie Technology 2: Hydrogen fuel cell cars
Zombie Technology 3: Wireless charging
Zombie Technology 4: E-roads
Paul Martin is a chemical engineer, and lifelong environmentalist. He’s a passionate advocate for electric vehicles (he built one himself), and a renewable energy advocate. He has spent 23 years at Zeton Inc. designing and building pilot and demonstration plants for the chemical process industry, helping clients bring new chemical process technology to market.