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Comment by gruez | Hacker News Reader

Presumably it's not on 24/7 and only activated when there's snow in the forecast. Also, keep in mind that the low energy alternative (ie. getting a guy to shovel it) is pretty energy consuming as well. Shoveling itself might not be burn much energy (in terms of joules/calories), but keeping the person alive is. Per-capita energy consumption in the US is 77.5 MWh (77.5 thousand kWh), or 37.3 kWh per working hour (260 working days per year, 8 hours per day).

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I don't get it what the 37.3 kWh are supposed to mean in this context. This is for sure not the energy required to keep a person 'alive', but all energy (manufacturing, transportation, ...) assigned to per person.

The energy consumption for a physical working person is approx 4000 cal per day (4.6 kWh). According to [1] it takes about 150 BTU (0.043 kWh) per hour / ft^2 to melt snow. To clear/melt an area of 5*15 meter this requires about 35 kWh.

(I have rough calculation of the energy required to melt 20 cm of -5°C cold snow and get a four times higher energy requirement, probably i have missed something.)

[1] https://www.pmengineer.com/articles/87603-radiant-snowmelt-s...

> Also, keep in mind that the low energy alternative (ie. getting a guy to shovel it) is pretty energy consuming as well. Shoveling itself might not be burn much energy (in terms of joules/calories), but keeping the person alive is.

Marginal changes in the number of people employed shoveling snow does not result in additional people being created (for positive changes) or destroyed (for negative changes), so the energy cost of keeping the person alive is not a cost associated with the alternative of having them shovel the snow.

You're correct that it doesn't cause new people to be created, but there's still the opportunity cost because the person is shoveling snow rather than doing something else productive.

They could shovel and be paid instead of going to the gym and pay /grin

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