# Evacuated Tube Transport

http://et3.com proposes maglev vehicles in long vacuum tubes for intercity transport. Accelerating vehicles to very high speeds with coil guns is expensive, so even though a launch loop without energy recovery wastes about 2.4x the kinetic energy of the vehicle, an in-tube loop accelerator will probably be much cheaper than a lot of switching electronics.

Assuming 2kW/tonne for levitation power P, 8300km between San Francisco and Tokyo, and a maximum acceleration of 10 m/s2. For an acceleration and deceleration time of ta the maximum velocity is 10ta and the trip time is ta + d/10ta. The energy used for a trip is E = 2(ta + d/10ta)+12ta2 joules per kilogram.

Assuming 500kg/passenger, and \$0.20 per kilowatt hour, the trip looks like so, versus varying acceleration times:

 accel time vmax trip time s trip time hr E accel E lev E total \$/passgr 20 200 41520.00 11.53 4800.00 83040.00 87840.00 2.44 40 400 20790.00 5.78 19200.00 41580.00 60780.00 1.69 41 410 20284.90 5.63 20172.00 40569.80 60741.80 1.69 60 600 13893.33 3.86 43200.00 27786.67 70986.67 1.97 100 1000 8400.00 2.33 120000.00 16800.00 136800.00 3.80 150 1500 5683.33 1.58 270000.00 11366.67 281366.67 7.82 200 2000 4350.00 1.21 480000.00 8700.00 488700.00 13.58 300 3000 3066.67 0.85 1080000.00 6133.33 1086133.33 30.17 400 4000 2475.00 0.69 1920000.00 4950.00 1924950.00 53.47 600 6000 1983.33 0.55 4320000.00 3966.67 4323966.67 120.11

The pollution cost will vary by the source of grid energy, and ticket costs will include operating expense, amortization of infrastructure, and profits. Given the \\$\\$\\$\\$\\$\\$\\$\\$ cost of infrastructure, a loop-driven ETT system won't happen soon.

ETT (last edited 2013-07-11 20:01:52 by KeithLofstrom)