By Delft Hyperloop, April 2019
One of the major advantages of the hyperloop is the low operational energy consumption compared to other modes of transportation. The magnetic levitation ensures no rolling resistance and the near vacuum environment takes away a significant share of the aerodynamic drag. Due to these techniques, the hyperloop can travel efficiently at speeds above 1000 kilometres per hour. However, the actual energy consumption of a hyperloop pod cannot be neglected. This article explains the most important aspects and gives an overview of the total operational energy consumption.
For the total usage of the system, many aspects can be taken into account. This article describes the critical aspects of a hyperloop: vacuum pumps, airlocks, magnetic propulsion, and passenger comfort. Next to these factors, 10% additional energy consumption is used for less significant factors not taken into account. All the values are calculated for a journey from Amsterdam to Paris but are similar to any other link in the European Network (as explained in Connecting Europe with a Hyperloop Network) of the same length. To determine the usage per passenger, it is assumed that every pod has a load factor of 50%, which is comparable to turn-up-and-go train systems. All values are calculated in kJ/passenger/km, to compare easily with other modes of transportation. An overview of the energy consumption per aspect is shown in the table below.
The vacuum pumps are needed for both bringing the tube to a near vacuum and maintaining this low pressure. It is expected that a complete pump down is needed twice a year for maintenance purposes, resulting in 0.27 kJ/pass/km. As air leaks into the tube through the wall, connections, welds and airlocks, the vacuum pumps will work continuously to maintain the vacuum environment. However, as the leakage is very small, this is negligible if expressed per passenger. The same goes for the airlocks that transfer the pods from atmospheric to vacuum environment and vice versa, as the size of the airlocks will only be slightly larger than the pods, minimizing the air that needs to be pumped out.
The propulsion, which is divided into accelerating to cruising speed and maintaining this speed, is done by a Linear Synchronous Motor. With an assumed LSM efficiency of 80% and a pod mass of 45 tons, 98 kJ/pass/km is needed to accelerate to a cruising speed of 1080 kilometres per hour. To overcome aerodynamic and magnetic drag and to maintain this speed for the remaining of the journey, 200 kJ/pass/km is needed using Electrodynamic Suspension for levitation.
To improve user experience, it is important that hyperloop pods have high passenger comfort. Energy is needed for comfort functions such as heating, ventilation and air conditioning inside pods. When comparing energy use with existing underground transportation modes, 36 kJ/pass/km is found. By adding 10% of all aspects for unforeseen energy costs, the total energy consumption of a hyperloop is 369 kJ per passenger per kilometre.
To make the hyperloop system more efficient, above-ground tubes can be covered using solar panels. In average West-European weather circumstances, 1 m2 solar panel surface produces 200 kWh. Assuming that 50% of infrastructure will be constructed above-ground, this is sufficient for at least 20 pods per hour in each direction. With a one-minute departure frequency, this is more than 30% of all operational energy usage of the connection between Amsterdam and Paris.
When comparing the hyperloop to other transport modes, the energy consumption is similar to that of conventional trains. Due to the near vacuum environment, it is slightly more efficient compared to a maglev train. However, taking into account the increased operational velocity, the hyperloop is by far the most efficient mode of transportation. By replacing short-to medium haul aircraft, energy consumption and emissions of passenger transport can be reduced significantly. An overview of the total operational energy consumption of multiple modes can be seen below.