Number 18 in the Clean Air Technologies Series.
Electrified, fixed-guideway transit systems exist in cities throughout the modern world. These can consist of tramways or electrified street railways, light rail, bus and more. With many a transit agency these days hard-pressed to do more with less, the prospect of finding ways to make every dollar go farther, well, there is a certain attraction about that.
Two technologies covered below have to do with contactless, catenary-free operation and energy storage.
First, with the creation of a “contactless,” catenary-free system, not only is it now possible for electrical propulsion power to be provided to fixed-guideway transit networks minus the overhead electrical catenary infrastructure, but a system along these lines can also provide for a more aesthetic system appearance at the same time.
Bombardier, in a May 26, 2010 press release, discusses PRIMOVE system basics.
“When running on conventional systems, trams and light rail vehicles take their energy from an overhead electrical line. Equipping the tracks and the vehicle with the PRIMOVE components also allows operation without a catenary. Cables laid beneath the ground are connected to the power conditioning and supply network. They are only energized when fully covered by the vehicle, which ensures safe operation. A pick-up coil underneath the vehicle turns the magnetic field created by the cables in the ground into an electric current that feeds the vehicle traction system,” explained Bombardier in the release.
In addition, and according to Bombardier in the release also, a power supply that is completely hidden from view not only means protection from the elements but continuity of service is assured regardless of ground and area meteorological conditions. What’s more, system installation is said to be easy. And, the nature of the system being what it is – contactless – the expectation is electrical components will last longer compared to those used in conventional operations.
“For historic centres such as Augsburg, one of Germany’s oldest cities, the PRIMOVE technology means that impressive cityscapes can now exist unencumbered by visual pollution from overhead lines,” Bombardier declares.
That covers the contactless, catenary-free operation bit. Now, as for energy storage, Bombardier in a Dec. 18, 2009 press release, touts the energy-storage capability of its technology known as the MITRAC Energy Saver.
State-of-the-art energy storage
“The MITRAC Energy Saver saves up to 30 percent energy and utilises an energy recovery system: three roof-mounted energy storage units use their capacitors to store the energy generated during braking, ready to release it again when accelerating or during operation,” information in the release noted. “The high performance double-layer capacitors of the MITRAC Energy Saver store up to 3 kWh per vehicle. When starting up and accelerating, vehicles require a particularly large amount of electricity and put a significant burden on the power supply network. This is reduced by about 40% with the MITRAC Energy Saver, allowing the network to be utilised more cost effectively.”
With this type of energy-storage system in place and with far better energy utilization, by virtue of this, presumably less utility-produced power would be required to propel transit vehicles. And with presumably less demand therefore placed on the electric grid supply, in effect, this would mean so-affected transit systems should be more efficient. And that being the case, logic tells me that with potentially greater efficiencies all around, the potential also exists for air quality improvement.
It is technologies like these and others that are no doubt helping electrified, fixed-guideway transit reach its full potential.