Solar energy is emerging as the next promising sector in Thailand.
LEFT The famous hanging garden at 158 Cecil Street in Singapore. NATIONAL PARKS BOARD OF SINGAPORE, SINGAPORE TOURISM BOARD
RIGHT A living wall at Kasetsart University’s woman dormitory on Phahon Yothin Soi 45 in Bangkok.
More than 1,000 applications for solar rooftop licences have been lodged with the Metropolitan Electricity Authority (MEA) headquarters on Ploenchit Road and at the Provincial Electricity Authority (PEA) on Ngam Wong Wan Road since late last month.
The Energy Ministry is accepting nationwide private sector proposals for solar rooftop licences from Sept 23 to Nov 15.
Half of the licences _ for projects with a combined capacity of 200 megawatts _ will be granted to the residential sector and the remainder to factories and commercial buildings.
Recently, the ministry increased its 2020 solar power target to 3,000 MW from 2,000 MW due to its lower costs and clean properties.
But advocates of so-called green roofs and vertical gardens say the government should provide more incentives for green initiatives as they save energy consumption by reducing heat in buildings.
They say high maintenance costs, expensive material prices and a lack of government support, meant they were not widely used in Thailand.
Assoc Prof Pasinee Sunakorn, from Kasetsart University's Faculty of Architecture, said green spaces can help reduce urban heat, which radiates from construction materials on the surface and roof of buildings.
According to the Bangkok Metropolitan Administration's Environment Department, Bangkok in 2009 had green space of only 3.29 square metres per person, four times lower than the international average of 15 sq m.
High maintenance costs and material prices, as well as a lack of state support hamper the growth of urban greenery, says Assoc Prof Pasinee Sunakorn.
Green roofs can reduce the temperature in buildings by eight degrees Celsius. Those with climbing plants are three to four degrees cooler.
Vertical garden plants include coral vines, Mexican creepers, ground ivy, gourd, honeysuckle and some orchid varieties.
But Ms Pasinee said maintenance of the high walls is difficult and costly.
Vertical gardens in Thailand are usually only found in luxury Bangkok properties including Siam Paragon, The Emporium, The Esplanade and high-priced condos in the Sukhumvit area. They function more as decorations rather than as benefits to the city.
Kasetsart University's Faculty of Economics has a vertical garden of around 200 sq m but costs 25,000 baht a month to maintain, Ms Pasinee said.
Vertical gardens absorb carbon dioxide and some toxic building materials. They also reduce glare. Some plants, such as the Rangoon creeper, are even edible.
There are two types of green roofs.
Extensive roof gardens require soil of at least 30 centimeters in height and a structure that can support the weight of the building, while intensive green roofs need light-weight materials.
"To promote vertical gardens and green roofs in Thailand, the government should support and subsidise investment as material prices and maintenance costs are so high," said Ms Pasinee, who also is director of the Center of Building Innovation.
Lok Yan Ling, manager of Skyrise Greenery, the horticulture and community gardening division at Singapore's National Parks Board, said the Singapore government encourages installation of green roof gardens.
Its incentives include a subsidy of up to 50% of installation costs, or a maximum of S$75 per sq m of rooftop greenery, and up to 50% of installation costs, or a maximum of S$750 per sq m, of vertical greenery.
The Singapore scheme was launched in October 2009. As of April 2013, 95 buildings had successfully applied for the incentive.
Of the total, 56% were educational institutions, followed by commercial (26%), government-owned (12%) and private residential buildings (6%).
Skyrise Greenery is also promoting a landscape replacement policy which requires building owners to build green areas when developing a new building. It also is allowing more floor areas for buildings with outdoor refreshment area on landscape rooftops, communal sky terraces, balconies, communal planter boxes or landscaped communal areas.
Ms Pasinee said green roofs on new buildings had been a construction requirement in European cities for many years. In Munich, Germany, building regulations have required green roofs on new buildings since 1984, with a subsidy of 50% of construction costs since 1992.
In 1996, green roof space totalled 10 million sq m in Germany. It now makes up 14% of the total roof area in the country. In London, "living" roofs and walls were promoted in 2008 and now comprise 1% of the total roof area.
A new building in New York, where at least 50% of the total roof area is green, will receive a tax deduction of US$100,000, accounting for 25% of the cost of the roof.
Japan's Tokyo Plan 2000, which started on April 1, 2001, requires any building with an area of more than 1,000 sq m to have green roof space of at least 20%. Japan aims to have a green roof area of 12 million sq m within 2015.