3 ms·

While I agree about aviation, rail is an entirely different problem, and big heavy things move great. For freight in the US, the worst case segment I know abou

While I agree about aviation, rail is an entirely different problem, and big heavy things move great. For freight in the US, the worst case segment I know about is ~700 miles. This can be handled with about 400-500 feet of battery cars, which is probably 5%-10% of train length. So the worst possible scenario is pretty close to feasibility with current tech. If railroads were to start investing in this level of battery, beyond saving a lot of fuel costs, they'd have a couple hundred MWh of battery at every rail station. This would be a significant grid asset, at least at the moment. In a decade, that level of storage is probably going to be extremely common. But in any case, there's significant opportunity for demand response payments, if not using the batteries for replacing peaking power on the grid.

Seattle3503 5y ago
Given the efficiency of rail, is fuel even a considerable part of their costs?
- epistasis 5y ago
  I don't know, actually! So some napkin math... Rail is 2% of transportation emissions, which is 29% of total US emissions [1], which was 6.558e6 metric tons in 2019 [2]. So rail is 3.8e7 kg of CO2 emissions. Diesel emits 10 kg/gallon [3], so that's 3.8e6 gallons, and at a cost of $3/gallon that's only $10M dollars out of what is an $80B industry [4]. That's so vanishingly small that I wonder if I have done something wrong here... [1] https://www.epa.gov/greenvehicles/fast-facts-transportation-greenhouse-gas-emissions https://www.epa.gov/greenvehicles/fast-facts-transportation-... [2] https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas... [3] https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculator-calculations-and-references https://www.epa.gov/energy/greenhouse-gases-equivalencies-ca... [4] https://railroads.dot.gov/rail-network-development/freight-rail-overview https://railroads.dot.gov/rail-network-development/freight-r...
  - epistasis 5y ago
    My mistake: the starting amount of CO2 is low by a factor of 1000, and therefore fuel costs are around $10B of the $80B industry. That's in line with my initial expectations, and cutting fuel costs by even, say, 30% could be a big win.

Seattle3503 5y ago

Given the efficiency of rail, is fuel even a considerable part of their costs?

epistasis 5y ago
I don't know, actually! So some napkin math... Rail is 2% of transportation emissions, which is 29% of total US emissions [1], which was 6.558e6 metric tons in 2019 [2]. So rail is 3.8e7 kg of CO2 emissions. Diesel emits 10 kg/gallon [3], so that's 3.8e6 gallons, and at a cost of $3/gallon that's only $10M dollars out of what is an $80B industry [4]. That's so vanishingly small that I wonder if I have done something wrong here... [1] https://www.epa.gov/greenvehicles/fast-facts-transportation-greenhouse-gas-emissions https://www.epa.gov/greenvehicles/fast-facts-transportation-... [2] https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas... [3] https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculator-calculations-and-references https://www.epa.gov/energy/greenhouse-gases-equivalencies-ca... [4] https://railroads.dot.gov/rail-network-development/freight-rail-overview https://railroads.dot.gov/rail-network-development/freight-r...
- epistasis 5y ago
  My mistake: the starting amount of CO2 is low by a factor of 1000, and therefore fuel costs are around $10B of the $80B industry. That's in line with my initial expectations, and cutting fuel costs by even, say, 30% could be a big win.