Hybrid Buses in Singapore (Y)

Bus Transport in Singapore is the most comprehensive and affordable means of public transport for the masses, with over two million rides taken per day on average on the buses of the two main public transport providers SBS Transit and SMRT Corporation. There are more than 300 bus services covering all parts of Singapore.

SBS Transit is the sole operator of double decker buses, lauched the first double decker bus service in 13 June 1977. They initially started with a few buses, but they increased their fleet with buses like the Mercedes Benz O305 and the Leyland Olympian. The Leyland Olympian was Singapore's First Air Conditioned Double Decker Bus, and they are still in service. The Volvo B10TL, the first stepless ultra low-floor bus was launched in 1999. Volvo B9TL wheelchair accessible buses began to be introduced in 2006. 

The Leyland Olympian

The First Volvo B10TL

 

A New Volvo B10TL

A Volvo B9TL in "Wheelchair accessible livery"

Bus the problem with such buses is that they are quite heavy, 14.56 tonnes with no fuel or passengers, to be precise. And because these Double-Decker Buses are so heavy, their fuel consumption will be equally bad, 0.7 kmph to be exact. And so, to turn green, and to be economical, SBS Transit have decided to bring in Hybrid Double Decker buses. And so came the Volvo B9TL Hybrid.

The Volvo B9TL Hybrid

The idea behind having a Hybrid is quite simple. The vehicle has two engines, one which is diesel powered, and the other which runs on electricity. And the electric motor does not need an external power supply. The diesel motor recharges the battery which relays current to the electric motor. As we also know, these buses are quite heavy, and a lot of torque is required in order to get the bus moving. Anyone with a little knowledge on electric motors would be knowing that electric motors don't have a high "horsepower" output, but they instead give out a lot of torque. For a diesel motor, it takes a lot of fuel to develop such huge amounts of torque. So using an electric motor to power the bus from 0-30 kmph, results in a lot of fuel being saved. This system of Electric/Diesel motors works perfectly for Singaporean roads, as there are traffic signals everywhere, and there is a lot of "stop-start" involved. But after the bus exceeds a speed of 30 kmph, the diesel motors take over and power the bus. It also recharges the batteries. The batteries also get charged from current generated due to braking. Whenever a vehicle brakes, there is energy generated. Most of this energy is lost in the form of heat. But in Hybrids, the energy is harvested and stored in the batteries. The system works similar to that of the "Kinetic Energy Recovery System" (KERS) in Formula 1. 

So, we have seen that hybrid buses are quite efficient and clever. Some official involved with the production of the bus claim that the bus will result in a 30% improve in fuel efficiency, which is very good news. But then, there are some disadvantages to Hybrid Buses. The biggest disadvantage is the Cost of the bus. The vehicle has 2 engines, and this drives the cost of the bus high. It also has some expensive systems and technology. But then, cost is just a minor speedbump in the path towards eco-friendliness.

Having said that, SBS Transit have announced on 13th August 2009, a order of 150 Volvo B9TL chassis with Volvo D9B310 engines, ZF Ecolife 6-speed gearboxes, and Wright Eclipse Gemini 2 bodywork as part of a fleet renewal programme costing  S$87 Million.. This order was followed by an additional order for another 300 buses at a cost of S$158 Million in September 2010, also with similar specifications, bringing the total up to 450.

The first unit was handed over to SBS Transit by Wrightbus Ltd. in mid-September 2010, and is in service as of November 2010. The fleet renewal programme also means that the first generation Leyland Olympian air-conditioned double decker buses will be withdrawn from service in the near future.