121–130 of 399 posts
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So I did the math and the average water tower holds something like 1/2 kWh worth of power. (50m tall, storage of 1m gallons, efficiency of 90%) Hydro power storage is fantastic but needs truly ridiculous amounts of water and height deltas to make sense.
You probably made a mistake somewhere. 3.8Mg * G * 50m ~ 1700M Joules which is about 500kWh.
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This is fascinating. So they are essentially harvesting the gravitational potential energy of the iron ore at altitude to charge the batteries (and then some) for the cargoless return trip. Outstanding.
Reminds me of this dam operation around here that pumps water up to a mountain top reservoir during the day when power is cheap and then lets it go at night when it can generate and sell the electricity for more money. I was always in awe of the lake size battery they created.
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Seems like a lot of physical infrastructure spread out over a lot of area for little gain. Little gain because it doesn't feel like charging at fixed stations is so bad, and it's not something folks need to do that often. There's other challenges too. You'd also need to build some system for billing, such that people don't start to steal power. Do we trust the cars to meter themselves? Or do we try to have the line m…
The other advantage is coordination and self driving. You could pretty much get in the charging lane, go to sleep and wake up in chicago. The whiskers can provide steering and other vehicle coordination if you think of them as power + data.
Requires a lot of smart infrastructure that we don't have but it seems like one of those things that should be doable once we've figured out autonomous driving...
The most spectacular example of regenerative braking are trains that are used in Scandinavia, heavily loaded with iron ore that is transported to the coast: "In Scandinavia the Kiruna to Narvik electrified railway carries iron ore on the steeply-graded route from the mines in Kiruna, in the north of Sweden, down to the port of Narvik in Norway to this day. The rail cars are full of thousands of tons of iron ore on th…
What does the equation look like when you subtract the energy used in the actual mining, though?
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> Just embed some wires in the road... No offense but that is the most loaded phrase I've heard this week. That would be a major overhaul of both roads and electric car designs.
A somewhat more practical approach: https://www.theverge.com/2019/5/9/18538030/germany-ehighway-...
There's a test in Sweden that uses power rails embedded under the road surface. I like that approach because it's more versatile and looks better, but on the other hand it's also more expensive.
Regenerative braking is so neat. I drove up a steep windy road to go on a hike with my plugin hybrid. On the way down I tried to let gravity do all of the acceleration and regenerative braking do all of the deceleration. At the bottom of the hill I had racked up +3 miles in total. Another fringe benefit is that brake pads wear out slower and produce less pollution.
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Hah, don't try it in Europe either, max towing speed in Europe is 40km/h or 25mph. I guess a tow truck with a bed that has a rolling road would be an idea, prop up the car so the weight of the car isn't actually exerting force that makes the wheels harder to turn/cause extra wear. Or the "rolling road" can be replaced be a contraption that attaches to the wheels by e.g. its rims, and spins it.
@Peloton, here is your next big idea
So he was getting supercharger speeds (50% battery in about a half hour) which is awesome! The Tesla has its own built in "supercharger" if you can find an alternative way to power it. My idea then is this - could a dyno be modified to be powered and function as competitive to a Tesla supercharger? Basically towing it in-place. It would be rad to see this work! I could imagine connecting it to a geared waterwheel for…
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That would be a neat test. Find a steep hill, preferably as straight as possible, and test how many times an electric car can traverse it before running out of batteries. Would the distance traveled exceed that on a flat road with no generation? By how much? I'm sure someone in San Fran has already tested this.
My intuition would say you'd never have longer range driving up and down a hill compared to driving flat in a straight line (and never braking). I would imagine that at best, you could maybe match the range. If there's any scenario where going up and down a hill would yield more range than driving flat, I'd be very interested in how/why.