Clear The Air Energy Blog Rotating Header Image


Misdirected energy: Hong Kong City University roof collapse highlights danger of adding vegetation in a bid to go green

Adding greenery may be too much for a roof to bear, compounded by laxity over the submission of building plans for structural changes

The giant rooftop that collapsed at a City University sports centre and left three injured has highlighted the potential threat of adding rooftop vegetation, a novel way to fight the heat-island effect, to old buildings.

The accident, which could have injured hundreds of people originally scheduled to attend a dinner event on Saturday night, also called into question the lack of government supervision of this kind of rooftop vegetation, which is promoted by the Environment Bureau.

At the City University, the vegetation was understood to have been added last year to the top of Chan Tai Ho Multipurpose Hall, which was completed back in the 1990s.

While the roof was not designed to hold anything substantial – as indicated in the building plan submitted to the government in 1989 – vegetation that would have required a roof five times stronger was nonetheless planted last year, as part of the university’s pledge to go green.

“The figures showed that the rooftop was not supposed to hold a lot of [vegetation],” said Vincent Ho Kui-yip of the Institute of Surveyors.

Ho said the current building regulations relied heavily on owners’ own initiative in submitting a plan for approval if they altered a building’s structure. But the Buildings Department would never know if owners skipped this procedure.

He said the department should remind owners to resubmit plans for new structures.

Professor Jim Chi-yung, an expert on urban soil science and a staunch advocate of green roofs, said it would be “very risky” to install a green roof on a structure – especially an existing one – that did not meet loading capacity standards.

“The roof must be able to take the weight of the dead loads of soil, vegetation and drainage as well as the life loads, which include people walking on it,” Jim said. “The loadbearing capacity must be bigger than the sum of the dead load and life loads.”

He added that the drainage design for a green roof could be an Achilles heel, as it was often not done properly. Poor drainage could lead to water gathering on the roof, leading to dangerously high loading which could jeopardise the roof structure.

But experts asked the public not to panic over the environmentally friendly measure.

“It is already an accepted practice around the world,” said Leung Man-kit of the Green Building Council’s policy and research committee.

City University said on its website that the green roof top “could achieve an energy saving of about 60 kWh/sq m per year, a reduction in CO2 emissions of about 3.2 tonnes per year, [equivalent] to planting 137 trees”.

The Buildings Department could not confirm whether a new plan was submitted before the university added the rooftop vegetation. The university said on Friday night that the contractor had made proper assessments.

More Reflective Roofs and Pavements Could Help Offset Climate Emissions

Washington, DC, February 19, 2010

Increasing the reflectivity or “albedo” of roofs and pavements in urban areas could offset greenhouse gas emissions by a significant amount, according to a paper published last month in Environmental Research Letters. The research performed by scientists at Lawrence Berkeley National Laboratory and NASA’s Goddard Space Flight Center shows that a 25% and 15% increase in the albedos of roofs and pavements, respectively, in urban areas, could lead to an offset of approximately 57 billion tonnes of carbon dioxide.

“Increasing urban albedo is something that should be done now to buy time for implementing other near-term and long-term climate mitigation strategies,” said Durwood Zaelke, President of the Institute for Governance & Sustainable Development.

Surfaces with high albedo reflect more solar radiation, preventing the radiation from heating the surface and the atmosphere. Introducing “cool roofs” and more reflective paving materials could replace some of the albedo that has been lost through the melting of Arctic sea ice.

“Although it does not solve the root of the climate change problem – substantial reductions in CO2 and other climate forcers are essential for that – urban albedo can delay the onset of more severe climate impacts, and reduce the risk of passing the thresholds for abrupt and irreversible climate changes,” added Zaelke.

Because CO2 emissions can remain in the atmosphere for up to 1,000 years, there is an urgent need for complementary, fast mitigation measures that will result in significant near-term reductions to avoid passing the tipping points for abrupt climate change, which may only be decades away. In addition to increasing urban albedo, such strategies include reducing emissions of black carbon soot, methane, and tropospheric ozone, as well as using the Montreal Protocol ozone treaty to phase down hydrofluorocarbons, which could prevent the emissions of more than 100 billion tonnes of CO2-eq. by 2050. Carbon-negative measures such as better forest management and production of biochar will also be necessary to bring atmospheric concentrations of CO2 back down to safe levels.

For more information, see:

Radiative forcing and temperature response to changes in urban albedos and associated CO2 offsets by Surabi Menon, Hashem Akbari, Sarith Mahanama, Igor Sednev and Ronnen Levinson (Environmental Research Letters, Jan 2010).

Can China Clean Up Its Act?

BusinessWeek by Adam Aston – May 14, 2009


Beijing has big plans to curb pollution and start a cleantech industry. But the global recession and looming trade frictions will test its resolve

China’s unprecedented growth in recent years has come at a terrible price. Two-thirds of its rivers and lakes are too polluted for industrial use, let alone agriculture or drinking. Just 1 in 100 of China’s nearly 600 million city dwellers breathes air that would be considered safe in Europe. At a time when arable land is in short supply, poisoned floodwaters have ruined many productive fields. And last year, ahead of most forecasts, China passed the U.S. to become the world’s largest source of greenhouse gases.

The immensity of these troubles has produced a result that may surprise many outside China: The nation has emerged as an incubator for clean technology, vaulting to the forefront in several categories. Among all countries, China is now the largest producer of photovoltaic solar panels, thanks to such homegrown manufacturers as Suntech Power (STP). The country is the world’s second-largest market for wind turbines, gaining rapidly on the U.S. In carmaking, China’s BYD Auto has leapfrogged global giants, launching the first mass-produced hybrid that plugs into an electrical outlet. “China is a very fast follower,” said Alex Westlake, a director of investment group ClearWorld Now, at a recent conference in Beijing.


Understanding they are in a global race, China’s leaders are supporting green businesses with policies and incentives. Beijing recently hiked China’s auto mileage standards to a level the U.S. is not expected to reach until 2020. Beijing also says it will boost the country’s share of electricity created from renewable sources to 23% by 2020, from 16% today, on par with similar targets in Europe. The U.S. has no such national goal.

While most environmentalists applaud these developments, China watchers are voicing two very different sets of concerns. Some question whether China will really stand by its ambitious targets and are worried by signs of backsliding as the recession in China’s key export markets drags down economic growth. Another group, interested mainly in America’s own industrial future, fears that China’s growing dominance in certain green technologies will harm budding cleantech industries in the U.S. After all, China’s emergence comes just as the Obama Administration is trying to nurture these same types of ventures, hoping to generate millions of green jobs. Many of these U.S. businesses will have trouble holding their own against low-price competitors from China.

Beijing’s green intentions will soon be put to the test. China is in the midst of the biggest building boom in history. A McKinsey & Co. study estimates that over 350 million people—more than the U.S. population—will migrate from the countryside into cities by 2025. Five million buildings will be added, including 50,000 skyscrapers—equal to 10 New York Cities. And as quickly as new offices and houses multiply, they are filled with energy-hungry computers, TVs, air conditioners, and the like, sharply increasing demand for electricity, which comes mainly from coal-powered plants.

Environmental groups say it is therefore critical that Beijing promote rigorous, greener standards. And to some degree, that’s happening. A government mandate states that by the end of next year, each unit of economic output should use 20% less energy and 30% less water than in 2005. Portions of Beijing’s $587 billion economic stimulus package are earmarked for cleantech. On top of that, in March the Finance Ministry unveiled specific incentives to spark solar demand among China’s builders. Included was a subsidy of $3 per watt of solar capacity installed in 2009—enough to cover as much as 60% of estimated costs to install a rooftop solar array.

Steps like these will help Himin Solar Energy Group in Dezhou, Shandong Province. Founded in 1995 by Huang Ming, an oil equipment engineer turned crusader against the use of fossil fuels, the company is the world’s largest producer of rooftop piping systems that use the sun’s rays to heat water. Its eye-catching headquarters, the Sun-Moon Mansion, showcases these heaters, which Himin cranks out in immense volumes—about 2 million square meters’ worth each year, equal to twice the annual sales of all such systems in the U.S. Because its water heaters sell for as little as $220, they are becoming standard in new housing complexes and many commercial buildings across the country.

Broad Air Conditioning, based in Changsha, Hunan Province, is also set to profit as Beijing pushes toward its green targets. By using natural gas and so-called waste heat from other machines and appliances instead of electricity, Broad’s big chillers can deliver two to three times more cooling per unit of energy than a conventional unit. In a similar fashion, Haier, headquartered in Qingdao, Shandong Province, combines low-cost manufacturing and a variety of advanced technologies to create affordable, energy-sipping refrigerators and other appliances. During the 2008 Beijing Olympics, Haier supplied more than 60,000 such devices for visiting athletes and tourists to use.

As these and other domestic players bump up against technological obstacles, they can draw on the expertise of many of the world’s top multinationals. In return for access to its domestic market, Beijing asks such companies as General Electric (GE), DuPont (DD), 3M (MMM), and Siemens (SI) to share their technology, help upgrade their China-based supply chains, and spread industrial processes to make manufacturing more efficient. These aren’t simply green practices, says Changhua Wu, Greater China director of the Climate Group, a consultancy in London that partners with companies to combat climate change. “They’re best practices.”

GE, for example, has transferred expertise to Chinese partners in everything from wind turbine construction to the building of low-pollution factories. At the Beijing Taiyanggong power plant, waste heat from the combustion process is recycled, resulting in around 80% efficiency, more than double the rate of most conventional power plants in the U.S. The bulk of GE’s sales of turbines for power plants in China are the ultra-efficient models. David G. Victor, a Stanford University professor who has studied China’s electric grid, says some of the coal plants being built there are “much more advanced than those we see in the U.S.”

Wal-Mart Stores (WMT), which buys some $9 billion worth of goods in China each year from some 20,000 vendors, infuses its supply chain with the latest ideas about energy efficiency. For example, Chinese factories that work with Wal-Mart are obliged to track vast quantities of data on energy use and make the information available for audits. “Many Western companies can’t track their own energy consumption,” says Andrew Winston, consultant and co-author of the book Green to Gold.

China’s early achievements in cleantech owe a lot to collaborations such as these. The benefits: China cleans up its own pollution, and the government-backed initiatives in solar and wind help drive down the cost of renewable energy systems in countries around the world.

But there is a downside. The rock-bottom prices for made-in-China green technology could make it impossible for cleantech ventures in the U.S., Europe, or Japan to compete. How, for example, will they go up against Suntech Power, based in Wuxi, Jiangsu Province, the world’s lowest-cost manufacturer of standard solar panels? The U.S. boasts plenty of advanced technology. But any efforts by Washington to nurture this sector could be quickly undercut by a flood of Chinese-made solar panels. Such a deluge is likely if there is a big increase in public subsidies for rooftop solar systems. “What [that would] do is create 10,000 Chinese jobs,” says Roger G. Little, chief executive of Spire Corp. (SPIR), a leading U.S. maker of manufacturing equipment for photovoltaics. “If we import all the [solar] modules, it will obliterate U.S. manufacturing” in this area.

A similar scenario exists in the much heralded area of electric vehicles. BYD, headquartered in Shenzhen, started selling its first plug-in hybrid, the F3DM, last year. It beat Toyota (TM) and General Motors (GM), both of which are developing such “plug-ins,” and hit the market with a price tag they probably can’t match: just $22,000. Henry Li, a BYD general manager, says the company will roll out a version of the car in the U.S. in 2011. Chevy’s answer to this car, called the Volt, is expected to cost about twice as much and won’t be out until next year.

How did BYD pull off this coup? Part of it is just being the new kid on the block. Today’s automobiles, with their advanced combustion engines, are the most complex mass-produced goods ever made, assembled from thousands of highly engineered parts provided by a web of suppliers. It’s difficult for a Chinese startup to compete on such a sophisticated playing field. But the emergence of a new, green-vehicle category clears the way. BYD was able to break in by leveraging its background as a battery maker. When it ran into technical hurdles, the company could draw on a deep pool of inexpensive, well-trained talent at China’s top engineering schools. BYD is also a leader in pure electric vehicles, the logical next step. The government is now putting some muscle behind BYD’s push. It is heavily subsidizing electric-car sales in about a dozen cities—in a stroke, making China the world’s biggest market for such advanced vehicles. Its goal is to boost domestic output of battery-powered vehicles to a half million per year in 2011.

How Washington and the beleaguered U.S. auto sector might respond to a wave of inexpensive electric vehicles from China is difficult to predict. And it is also unclear how China’s cleantech efforts in cars, energy, and other areas will be affected if key markets such as the U.S. and Europe don’t recover quickly from the recession. Chinese makers of solar photovoltaics, including Suntech, export about 98% of their production. They have been battered this year by a collapse in demand in Germany, Spain, and Japan, China’s top markets for solar gear. Suntech’s factories are currently running at half of last year’s capacity.

Even inside China, academics and business executives say Beijing needs to do more to bolster cleantech initiatives and make them recession-proof. For example, without better information on how such policies as the current Renewable Energy Law are to be enforced, “many of the terms are meaningless,” complains Himin’s Huang. And even when the terms are clear, companies don’t always adhere, says Zhou Weidong, the Guangzhou-based China director at the Business for Social Responsibility, a global consultancy promoting sustainable business practices: “Paying penalties is cheaper than complying with the law in many areas.”

At times, it seems as though Beijing is pedaling in the wrong direction. Late last year, China’s Environmental Protection Ministry loosened review standards on potentially polluting industrial projects. In an economic crunch, “environmental protection is downplayed to second, or third, or even fourth priority,” observes Guo Peiyuan of SynTao, a corporate social responsibility advisory firm in Beijing.

While acknowledging there has been some backsliding, most China watchers say the government is unlikely to stage a full-throttle retreat. Too much of its export growth is contingent on meeting strict environmental regulations. And Beijing recognizes that Chinese society can’t tolerate much more environmental degradation. The World Bank estimates damage from pollution—everything from decimated fisheries to premature human death—saps nearly 6% of China’s gross domestic product each year as well. For economic reasons alone, it will be difficult for China to turn back the clock.

with Charlotte Li and Pete Engardio

Aston is Energy & Environment editor for BusinessWeek in New York.

Tax Break Set For Electric Vehicles

February 25, 2009 – Environment

The First Registration Tax exemption for electric vehicles will be extended five more years to promote their use. The exemption is due to expire March 31, but will be extended five years instead of three years as in the past.

In his 2009-10 Budget today Financial Secretary John Tsang said promoting the use of vehicles which are more energy efficient and emit no exhaust will create business opportunities.

He will lead a steering committee to study their wider use in Hong Kong, conduct in-depth studies and make recommendations from the perspectives of economic development, town planning, industry, technology, environmental protection and transport.

The Government will study the feasibility of jointly promoting electric vehicles with manufacturers, and be actively involved in testing them to introduce them into the local market early.

“We will also consider introducing such vehicles into the government fleet when the related technology has matured and the vehicles are available on the market,” Mr Tsang said.

The Government will study the feasibility of providing recharging facilities in public multi-storey car parks and explore ways of encouraging the business sector, including property developers and private car park operators, to set up such facilities.

Saving energy

Noting buildings account for 90% of Hong Kong’s total power consumption, Mr Tsang said the Environment & Conservation Fund will allocate $450 million for private building owners to conduct energy- carbon audits and energy efficiency improvement projects. More than 1,600 projects will be subsidised.

Another $450 million will be allocated to conduct minor works in government buildings in the next two years to install energy-efficient lighting, retrofit plumbing with water-saving devices and incorporate energy-efficient features in air-conditioning, elevator and escalator systems.

Going green

In the coming year Greening Master Plan projects undertaken by the Civil Engineering & Development Department will cover the whole of Hong Kong Island and urban Kowloon.

Landscaping features will be provided on 500 old slopes and greening work on the rooftops of 40 government buildings through additional funding for minor works. Schools and other non-profit-making organisations will also be subsidised to conduct greening work.

Mr Tsang said Hong Kong will co-operate with Guangdong to transform the Pearl River Delta region into a green and quality-living area with a cluster of high-tech, low-pollution and low-energy-consumption cities.

“We will further develop regional high-tech recycling industries, and encourage enterprises to adopt advanced technologies for cleaner production, energy saving and emission reduction,” Mr Tsang said, noting promoting a green economy will enhance Hong Kong’s overall competitiveness and make it a more liveable city.

Tenants Won’t Pay For Green Office

Olga Wong, SCMP – Feb 20, 2009

More than half of grade A office tenants are not willing to lease green space at higher rents despite the fact that such features save on work costs, a survey has found.

The survey also found 40 per cent of tenants would pay higher rents if the increase were not too much – not more than 20 per cent of the price of offices without green features such as power-efficient lighting and air conditioning, and more natural light.

Global real estate services firm Jones Lang LaSalle polled 20 major local developers and 80 grade A office tenants last summer. It was conducted to identify problems in promoting the city’s green buildings. No margin of error was provided in the survey.

Although occupiers understand that it is more costly for developers or landlords to build and operate green buildings, many of them are not prepared to pay more for these premises,” said Marcos Chan Kam-ping, Jone Lang LaSalle’s greater Pearl Delta area research chief.

The survey showed 40 per cent of tenants would not pay more to lease an office in a green building and 13 per cent added that they should pay lower rents.Mr Chan said the survey did not ask why tenants wanted to pay less for a green office.

If the rent on an office with green amenities is 20 per cent higher than that of an office without such features, the survey found that no tenant is willing to rent it. However, 40 per cent said they would if the rent was 10 per cent higher.

Eighty per cent of developers had no mission statement on sustainable properties although commercial buildings consume 66 per cent of the city’s electricity. Seventy per cent said the major hurdle in adopting green measures was the high initial capital cost and the length of time before any returns could be seen.

Mr Chan urged the government to use more incentives to encourage developers to design more green buildings. “In the US, green building plans enjoy a faster approval procedure. This benefits developers, especially when the property market is going up,” he said.

William Lai Hon-ming, the firm’s head of property management, said conducting an energy audit helped companies save on costs. “Few know that using a water-cooled air-conditioning system can save at least 20 per cent of energy costs and the capital cost can be recovered in five years,” he said.

Those Who Dare May Gain

David Chan, SCMP – Updated on Jan 21, 2009

Investment opportunities remain in the mainland property market despite the effects of the global financial crisis, and one emerging asset class that may reward investors are “green” buildings.

Part of the 4 billion yuan (HK$4.54 billion) stimulus package unveiled recently was earmarked for the development of greener buildings running on lower-polluting energy supplies and built with an eye to conservation and an environmentally friendly infrastructure.

What we may see in the near future are very different greener properties being developed which may offer interesting new investment opportunities.

Indeed, many recent homebuyer surveys indicate that green projects offering greater energy efficiency are becoming key deciding factors and this trend should encourage the development of a “green is good” approach to development across China.

It is worth noting that the initiatives are considered to go much further than provisions contained in Hong Kong’s proposed energy code which is scheduled for a first reading in the Legislative Council some time this year.

As always the three rules of property investment – location, location, location – also still apply.

However, investors should proceed with caution and an eye on the timing of their entry into the market because the general consensus is the mainland, Hong Kong and the rest of the world will experience a deep economic recession this year.

Less certain is how long the downturn will last and how severe it will be although by one measure – jobs – analysts are forecasting that unemployment in Hong Kong could reach 6 per cent this year.

The property sector is no exception to the list of casualties, with demand and prices dropping across the board.

So what will be the property investment outlook for the Year of the Ox?

First, it is important to bear in mind that the downturn has affected China with recent reports indicating that gross domestic product growth will slow this year to possibly below 8 per cent. This has already triggered declines of up to 30 per cent in property prices for commercial and residential markets in tier-one cities, and 20 per cent in tier-two cities.

In Hong Kong, we have seen an even greater drop of 40 per cent in luxury stock and up to 30 per cent in the mass market.

For example, China Vanke (the mainland’s largest residential developer by market capitalisation) has cut prices of projects in Guangzhou by 30 per cent and has also either slowed or suspended indefinitely construction on some projects to reduce inventory levels.

During the last downturn to affect Hong Kong – the severe acute respiratory syndrome epidemic in 2003 – property prices fell precipitously. Those buyers confident that the market would rebound used the opportunity to buy and as a result were rewarded with impressive gains as property prices rose to record highs last year.

So, presuming you are able to stay employed and have built up a nest egg over the last few years could this experience be repeated?

“Green” investment themes aside, location should continue to head investor’s shopping lists and Shanghai should not be dismissed since the 2010 World Expo will generate renewed interest in the property market. The completion of an upgraded and extended transport infrastructure (and more to come), will make property along the new metro stations attractive.

It is worth noting that the capacity of the Hongqiao airport will be vastly expanded by the completion of a second terminal building, enhancing its status as an air transport hub.

In Beijing, the areas which have been developed by Soho China are also of interest as is the site of the 2008 Olympic Games which is likely to be preserved as a landmark with its impressive bird’s nest stadium and water cube aquatic centre. This should have a knock-on effect for the neighbouring residential market.

Southward, development along the Guangzhou-Shenzhen-Hong Kong Express Rail Link, connecting Guangzhou, Dongguan, and Shenzhen in Guangdong province to Hong Kong, should be followed.

When completed, the expected travel time between Guangzhou and Hong Kong will be cut to 48 minutes.

In Shenzhen, the Baoan Airport railway link should help to transform the airport from primarily a domestic operation into an international hub, adding potential investment opportunities around the locality.

Conversely, it may prompt the Hong Kong government to reconsider the environmentally destructive plan for a third runway at Chek Lap Kok.

For second-tier cities, investors could look westward at Chengdu where the government has earmarked 260 billion yuan for rebuilding work for the region with the city as the centre of development activities.

While China will be affected by events internationally, it is worth noting that world economies are all interconnected and hence the flow of funds goes to markets offering relatively better stability and sounder economic prospects.

With the United States and Europe already into deep and possibly prolonged recession, China remains a comparatively better investment market in which fund managers may park their assets in the medium and longer term.

There is no escaping the economic downturn which is likely to affect Hong Kong and the mainland this year. However, returns are likely to be on offer for those investing in a quality project across the border.

The ox might still turn into a bull this year for those who dare.

David Chan is an architect and a partner of China-based property consultancy DKL Partners

Kwai Chung College Gives Green Light To Solar Power

Colleen Lee, SCMP – Jan 17, 2009

A secondary school in Kwai Chung is to go green and use solar energy to power lighting on two of its floors from April.

Wong Shiu-hung, principal of the Kwai Chung Methodist College, said he expected the initiative to cut about 30 per cent of the school’s electricity bill of more than HK$300,000 a year.

“I hope the project can be tied up with the studies of physics, geography and integrated science as it involves environmental protection and the conversion of the sun’s energy into electricity,” he said.

“Students and visitors can see how it works and learn more about solar power.”

He said exhibition boards would be put up to explain the application of solar energy and how common it was in the city.

Mr Wong said that by training students to act as guides, he wanted to arouse pupils’ interest in and public awareness of green power.

The project was funded by the government under the Environment and Conservation Fund at a cost of HK$499,728.

The Legislative Council’s finance committee injected HK$1 billion into the fund last year to support green projects by local non-profit making groups, including schools.

Mr Wong said 36 solar panels, measuring 136.5cm by 98cm each, would be fitted on the roof of the school’s old wing by early April to convert light from the sun into electricity. He said these could power the lighting of the upper two floors of the four-storey building. The lighting of corridors and 16 classrooms would be supplied by solar energy on sunny days and by CLP Power (SEHK: 0002) on other days, he said.

The operating cost of the facility was low and its eight batteries, at about HK$2,600 each, would need replacing about every seven years.

A weather station would also be set up on the roof to measure the temperature and humidity.

Substation Uses 15pc Less Power With Roof Garden, Sun And Wind

Ng Yuk-hang, SCMP – Updated on Dec 26, 2008

Two windmills on the roof of a grey building in Marsh Road, Causeway Bay, might not mean much to the casual observer but they are clues to the unique character of what Hongkong Electric calls the “first green substation in Hong Kong”.

The Marsh Road substation, which came into use in August this year, serves Wan Chai, Admiralty and Central, including the Tamar site where the new government headquarters will be built.

Hongkong Electric said the project cost HK$100 million, of which 2 per cent was spent on environmentally friendly facilities.

The six-storey substation uses 15 per cent less electricity each year than traditional substations.

That amounts to 250,000 kWh, or the equivalent of a month of electricity used by 714 families, according to Tso Che-wah, the power company’s general manager for projects.

The British-made windmills and 16 solar panels provide enough energy to light the entire substation.

Meanwhile, the building uses light-emitting diode tubes and energy-saving 16mm fluorescent lights, which consume less energy, have a longer lifespan and lead to lower carbon dioxide emissions.

Dr Tso said the substation was characterised by its rooftop garden, whose plants helped to lower the interior temperature by 2 degrees Celsius – in turn saving 10 per cent of the energy used each year on air conditioning.

The plants are watered mainly by rain, which is collected and stored in a tank on the roof. That saved about 180,000 litres of water a year, Dr Tso said.

The substation had been built in an environmentally friendly way, he said. It used concrete that contained 5 per cent fuel ash, from the company’s power station on Lamma Island.

Further, the rooftop was paved with recycled plastic waste.

Inside the building, elevators are switched off if left unused for more than 30 minutes, while extra windows for ventilation in the corridors reduce the need for air conditioning.

The Marsh Road substation was built to “accommodate community development in the next decade”, Dr Tso said.

Hongkong Electric has about 40 substations on Hong Kong Island.

Some older substations had been renovated to include more environmentally friendly features.

For example, a rooftop garden was added to the Connaught Road zone station, which is next to the Harbour Building.

Future substations would all be green, according to Dr Tso.

On Other Matters …

SCMP – Updated on Dec 17, 2008

I refer to the letter by E. Delannoy (Talkback, December 9), criticising the MTR Corporation’s strategy on saving energy. He asked why it was “shutting down a number of escalators in stations at certain hours”, but still keeping the air conditioning at cold temperatures inside its carriages [from Tung Chung to Central]. I support his views on this issue for a number of reasons.

I wonder how much energy is saved by shutting off a number of escalators and compare that with how much is wasted by having air conditioning at such high levels over a long period on the trains. Air conditioning that keeps the temperatures so low inside MTR trains must consume a great deal of energy.

The fact is that passengers feel uncomfortable in the carriages when they are so cold. Therefore, one simple way to conserve energy would be for the MTR Corp to lower the temperatures.

It could also try to install a good ventilation system so it does not have to rely on air conditioning to provide a flow of air. I hope MTR Corp can look into these problems and rectify them.

Angel Chan, Tuen Mun

Degrees of Comfort

SCMP – Updated on Dec 12, 2008

Of the government’s initiatives to get us to be more environmentally responsible, perhaps the most effective has been the one espousing that office air conditioners be set at 25.5 degrees Celsius. It is a number many people seem to be aware of, as a quick straw poll proved. Whether the knowledge is put into practice is another matter, of course, but the fact that it seems the message has been widely disseminated is impressive. Here the praise must end, though: the information is only partly right.

This is one of those cases where authorities have only done half their job; 25.5 degrees is a summer setting, not applicable to the other nine months of the year. During colder weather, thermostats should be lowered according to the outside conditions. If outdoor temperatures are less than those inside, we are on average doing more environmental harm than good. Every extra degree of cold or heat raises usage – and fuel bills – by 10 per cent, after all.

The government announced in October 2004 that air conditioners in all public buildings should be set at 25.5 degrees during summer. It launched a “no freezing summer” campaign the following June to encourage the private sector to follow suit. The figure has since been frequently bandied about by officials, most emphatically by Chief Executive Donald Tsang Yam-kuen in 2006 when he removed his jacket and trademark bow tie in front of legislators to promote his “Action Blue Sky” policy.

His clear message was that dressing more casually meant rooms did not have to be so cold. Less electricity would be needed, meaning lower bills and less pollution from power plants. It was a strategy that cost nothing to implement and would save money and the environment. Brilliant.

The rare image of a dressed-down Mr Tsang could well be the reason so many of us have “25.5” memorised. I am sure it flits subliminally through our minds whenever we drift near an office thermostat. A quick check, an adjustment if necessary, and the working environment is as it should be, we tell ourselves. We get back to our duties, satisfied that we have done our bit for Hong Kong.

Gerry McMahon, the director of the specialist building services company Facilities Analysis and Control, put the problem in a nutshell: attaining a 25.5 degree temperature in winter would, in most cases, mean heating a building to a point where the majority of people would feel uncomfortable. Ambient conditions naturally determined indoor temperatures, so when they changed, air conditioners should be adjusted accordingly. Some heating may still be required to achieve desired temperatures, but the notion of pushing the target up to 25.5 degrees in winter was ridiculous. Why waste energy in winter just because someone had decided the setting would save energy in summer, he rightly asked.

I have been unable to find out exactly where that 25.5 figure comes from. Authorities have attributed it to “overseas research”; I assume this means work done by the American Association of Heating, Refrigeration and Air-conditioning Engineers, whose standards are widely accepted. To be fair, the government has suggested it for summer. It has not made clear, though, that it is inappropriate for mild or damp conditions – as Hong Kong generally experiences from the end of August to the start of June.

Lantau environmental campaigner Eric Spain has long argued that it is wrong to make firm rules. The only solution for comfort and economy should be indoor and outdoor sensors and controllers, to automatically ensure appropriate settings, he says. Based on extensive research, he suggests that depending on humidity, comfortable summer office temperatures are generally between 24 and 27 degrees and, during winter, 20 and 23 degrees. Public transport settings should be at the upper end of the scale during hotter, more humid months, and between 18 and 20 degrees at colder times because of air flows.

I can see the convenience of settling on the 25.5 figure. But authorities have done no one – or the environment – a favour by failing to make clear what should happen at other times of year.

Peter Kammerer is the Post’s foreign editor.