Snake oil. Seriously. Melt snow in northern climes? Think about it. IF there were enough sunlight to melt snow, why didn't the sunlight just, you know, melt the snow? Are they THAT much more efficient at absorbing the sun's energy? I don't think so.
Cost to buy, cost to install, cost to maintain, ... the economics just don't make sense.
In Michigan there are a number of places I know of where they have used heated sidewalks. They use a ridiculous amount of electricity and rarely help much if there's more than an inch of snow. There use is limited to government and universities where they don't look at the economics often enough of what they're doing.
Their snow-clearing literature says that they'll pump energy into the grid when possible, and suck it out for snow melting. Clearly a net-loss for snowmelt operations.
All the other obvious problems aside, it might be an interesting analysis to see if there would be sufficient yearly yield to offset snowmelting operations in winter. Snowfall is not constant, so "melt" operations might only need to run for a handful of days per year, depending on the location.
> it might be an interesting analysis to see if there would be sufficient yearly yield to offset snowmelting operations in winter
There doesn't need to be sufficient yearly yield. This isn't just trying to pay for itself by collecting electricity on clear days to melt snow. It'd still be a great solution if it uses far more electricity than it collects because it's competing with snow removal trucks. If it could be cheaper and more efficient than having trucks driving around dropping salt and plowing, it'd be amazing.
Even if it's a little more costly, the ability to keep all the roads clear, all the time, would be incredible and worth some added expense. Think about how much safer the roads would be if they could remain free of snow.
The energy costs of melting snow are huge. It's done frequently for small areas (private driveways, parking lots) where cost efficiency isn't a concern (the wealthy) or where heat energy costs are very low (geothermal sources, i.e. Iceland).
To do it on a wide scale would require ridiculous amounts of energy. I guarantee that nobody would be prepared to foot the bill for that, and these solar panels are highly unlikely to produce even a tiny fraction of the amount of energy required, unless you amortize their production over a longer period and store it somehow.
Unfortunately, it's not just a "little more costly", it's massively more costly, to the point where it's just not a good idea.
I wish this idea could work. I really really do. And not living in an area with snow means I don't understand how important this factor is.
But, the grid seems to be having a pretty hard time just dealing with the influx of solar power as it is. Initially, most power grids weren't designed to be receiving power. And all it takes it a cloud moving over a suburb to mean electrical companies are shutting down and then powering up generators. Which causes more wear and tear on the generators too.
I would LOVE to hear from an electrical engineer about that aspect of this proposal.
Lets put it this way: if you're anywhere you only have to melt snow a handful of days per year it is not worth it to have heating. Anywhere snow is seriously inconvenient this idea is silly.
Actually those areas are probably the best places to have heating. they won't have the economic need to invest in many plows and plow operators that will sit unused 95% of the time.
Even if they have to pump energy into them to melt the snow, I'd still see it as a HUGE feature, and a big bonus to the solar roadway itself. They are not just "solar roadways". They are also "smart roadways". The changing of signs and whatnot is also a big feature, although I'm a little worried of hacking with that one.
There is no chance these are going to be more effective or cheaper than the dedicated roadway snowmelt systems that exist today.
And, is there widespread adoption of roadway snowmelt systems? No. Why? Because the energy and maintenance required is simply immense. Even when you get energy for free (geothermal), it's rarely worth the cost and upkeep.
It's a nice idea but the maths just don't work out.
Offtopic to 'higherpurpose': Your comments are visible, but it looks like your last several months of submissions have all been autokilled. Since they look reasonable (and the last one looks quite interesting) you might want to write to Dan at hn@ycombinator.com and see what's happening.
Well I think, and I'm no thermal expert, that the 'plan' is to use energy from other parts of a grid system, where that energy is not needed. IE, use energy collected from a place with no snow, to melt the snow somewhere else.
Although, I will say it does not sound feasible, but I would love to hear an expert has to say.
Had the author simplified the formula for "Vanswer" rather than plugging in values for h & c, he would have gotten:
Vanswer = (Pi/6) * h^3
From which is it easy to see that the answer in this particular case is 36 * Pi but it also makes clear that the answer does not depend on R.