Picture of the Day: North Korea’s Solar Powered Bus
A bus with solar panels mounted on its roof is parked in the North Korean city of Nampho, in this still image from a program of the North’s Korean Central TV Station on Nov. 2, 2015. The bus, which is equipped with 32 100-watt solar panels, 50 batteries and a 95-kilogram electric motor, can run at a speed of 40 kmph, the broadcaster said. (Yonhap)
Well, they cannot rely on their electrical grid to run the broken down electric Soviet-era buses so they have to try something new. Actually, they probably just slapped some solar panels on top of an old diesel bus for propaganda purposes.
Bullshyt.
A standard bus is around 12×2.5 meters… 30 square meters.
Direct sunlight at a 90 degree angle gives 1000 watts/square meter but it is not noon all day… sun at 45 degrees gives 707 watts/square meter… etc… plus the bus isn’t tilted to the south so the sunlight never comes in at 90 degrees. A guideline is calculating 5 hours of sunlight a day (with tilted solar cells adjusted for the seasons)…
…so, best case of sunlight is much less than 30m2 * 5hrs * 1kw… 150 kilowatt hours per day (though probably 80% of this due to the bus not being tilted to the southern sun). Oh… and we assume there are never clouds.
Those solar cells are certainly no more than 19% efficient… and probably closer to 15%. Let’s say a crazy 20% for easy math.
150kwh of sunlight at 20% conversion efficiency is 30kwh per day.
So far we have greatly overestimated the amount of sunlight… and overrstimated the conversion… and pretended all electronics and storage are lossless… and the electric motors are frictionless… etc.
One horsepower is .7457 kilowatts… so we get 40 horsepower-hours per day from that bus solar system… likely closer to 35… or 30.
Some perspective…
Bus engines put out 300-500hp. School busses might use a 250hp motor but nobody likes it.
Car ACs require about 4hp… bus ACs require 25-40hp… meaning the solar system might run the AC for an hour.
And that, ladies and gentlemen, is why you shouldn’t believe the hype that your solar powered car is coming soon.
England’s green power requires diesel generators… 😛
Green power is the way to go… not due to some global warming nonsense… but due to pollution.
Unfortunately, there is so much politics and showmanship in green power that the truth is lost… be it unrealistic expectations based on pop-science hype to a dumbed-down population, unworkable systems designed with political concerns or corruption, or a failure to calculate return on economic/resource investment… etc… etc… etc.
This causes the ignorant to gush endlessly over green power… the average to see it as a scam to be suspicious of… and the educated to weep for what should be but isn’t.
So-called “Green Power” is so tightly coupled with government corruption and payola that the only way normal folks will ever trust it is for the government to get the heck out of the way. Entirely.
And yes, I agree there are cases for using nearly every technology; but not if it feeds a tax-sucking bureaucracy.
@Tagum City Tim, I agree that the photo is probably for propaganda purposes since it was shown on a state media broadcast. The regime may just be trying to create the impression North Korea has modern technology since Kim Jong-un has been trying to brand himself as someone bring technological advances to North Korea.