As part of an initiative to study the possibility of energy and cost savings for bus operators, 10 SBS Transit buses will be seen on the road with mini gardens on its rooftops for at least the next three months.
Known as Asia’s first green-roofed bus, the “Garden on the Move” initiative by urban greenery specialist GWS Living Art was launched on Sunday (5 May) at Lakeside Garden. The routes for these buses include one through the Central Business District and another through Orchard Road, and the fare for them are the same as regular buses.
In a joint press release by GWS Living Art, Moove Media, National Parks Board (NParks), Singapore Green Building Council (SGBC) and Temasek Foundation, it is said that the buses are fitted with a soilless roof system where the plants are secured on a lightweight mat called Gaiamat – commonly used for skyrise greenery, instead of the traditional soil.
Each of these public buses are outfitted with two patches of greenery on its roof, and the plants grow on a layer consisting of organic natural fibres weaved together, which is seen as a replacement for soil. Below that is a layer consisting of a water retention fleece that helps to absorb water and rain.
As such, this makes it cleaner, easier to maintain and more economical compared to other conventional green roof system, which are primarily soil-based, the statement revealed.
The statement also added that the entire purpose of this three-month research is to confirm whether green roof will result to a drop of temperature inside the buses, and a reduction in the fuel consumption used for air-conditioning.
According to the study, the greenery protects the surface of the bus from direct sunlight, lower exterior temperatures are likely to translate to lower interior temperatures, causing for a more efficient use of air-conditioning and a corresponding drop in fuel consumption.
To calculate the difference in temperature, thermal sensors will be kept underneath the plants and on the underside of the roof. In addition, checks will be carried out on the mats and thermal sensors once a week.
“This is a creative initiative that seeks to extend Singapore’s greening efforts, and which truly encapsulates the vision of a biophilic City in a Garden. We hope that this will spur others to explore other similarly innovative ways to green up Singapore,” said Oh Cheow Sheng, group director of NParks.
Dr Tan Chun Liang from the National University of Singapore, who is an advisor for the study, said that the temperatures of building exteriors with green roofs can be reduced by up to 20 to 30 degrees.
“An exposed concrete roof for a building could reach about 60 degrees on a hot afternoon. We want to see if this temperature reduction in building holds true for vehicles as well,” he noted.
Dr Tan added that green roofs could increase our thermal comfort outdoors as well. As such, he said, “It’s the same as having parks – you get cooler temperatures outdoors. Collectively, if we have enough vehicles with green roofs, we could reduce temperatures and increase our thermal comfort.”
Upon reading this news online, many netizens were not at all impressed with this initiative and they penned it down on the Facebook pages of Mothership, Channel NewsAsia and Yahoo Singapore. They said that the idea is ridiculous and it will be a breeding ground for mosquitoes and other bugs. If that is not all, some online users also added that the resources spent on these rooftop gardens could be used on other things like ensuring smooth running of daily bus operations.
On the other hand, some netizens suggested that installing solar panels or driving hybrid/electric buses will be a better option in reducing the outdoor temperature. One user said that if they really want to have garden roofs on buses, then they should “at least explore growing edible food in land scarce area” and “convert buildings to have edible green growing on top roofs”.