Hotels, especially the starred varieties, are big guzzlers of energy and water, perhaps the biggest. Each room consumes on an average 110 units per occupant per day and 150 litres of water! At present, in the country, there are about 10,000 rooms in the four and five star hotels. This number is poised to double by the Commonwealth games in 2010.

Goes without saying that an energy-starved nation where many do not have access to electricity has to do something about the wasteful use of energy.

Much can be done but it will have to start with regulations made compulsory. Architects and designers need to be given a mandate to reduce this energy budget. Much can be done, feel experts, by introducing control systems, individual metering, use of renewable energy, etc.

There is a Rs 15,000 crore potential for green building materials by 2010 by when there will be around 1,000 green buildings in India, comprising 4-5 per cent of the total building sector. (Now there are nine which are Leed certified and 80 ongoing projects registered under Leed.)

While the hesitation is still about initial capital costs which are about 4-6 per cent higher for green buildings, this is expected to come down as the market and supply get better. But consider how green buildings can cut greenhouse emissions by 40 per cent, it makes sense to invest in green technology.

There is need to invest in technology and building expertise. At Loughborough University, UK, research has been going on into looking at low carbon energy technology. Dr Dennis L Loveday, professor of building physics, who was in Bangalore recently, spoke on the various initiatives undertaken as also various studies.

In the UK, around 40 per cent of emissions are from buildings and of this 70 per cent comes from the domestic sector. “So this sector is very important. But while developing technology we need to keep the user in mind and offer an easily retrofittable technology. Good insulation is the starting point when considering the two key areas of space heating and water heating.”

Insulation to reduce loss of heat is being addressed by research at Loveday's university and elsewhere. Use of a kind of glass fibre that reduces heat loss, as also double glazed glass with a layer of vacuum in between has been found to be very effective but “we need some value engineering to be done to reduce cost.”
There is also work being done on solar PVs embedded into the system as also in the architecture. An interesting work is on fuel cells for energy requirements of buildings and Loveday's university has delivered 1 MW power from fuel cells.

In the UK there is a proposal to make all buildings zero carbon by 2016. Does the professor believe it is possible?
He clarifies that this could mean the new buildings as “working on structures already built is a bit more difficult and costly” but there are examples already of such zero emission townships. Like at Sutton, London where there is the Beddington zero energy project that does not add any carbon to the atmosphere by a combination of technologies, design and renewable energy use!

Loveday believes that the role of occupants is important. With smart metering to give user information on the use of electricity they use with each gadget, the user can know how to use energy sparingly. “Most don't know. For instance, a survey found that 6 per cent of domestic energy demand in UK is the result of stand by mode of gadgets like TV, CD player, etc. We are working on a technology that allows switch off at source without loss of memory.”

Bi-generation where fuel is used to generate electricity and the waste heat used for space or water heating, tri generation where the same heat is used for cooling are some other areas of work.

Heat pumps are another solution picking up. Heat can be picked up from air or water or land and the low grade heat upgraded to give a high coefficient of perform. “For each kw of electricity you can have the equivalent of four kws! But we need to make it more adaptable for domestic use now,” says Loveday.

Heat pumps basically work the same way as a refrigerator does in taking away heat from the surrounding and delivering it elsewhere.

Design of homes can also reduce the heat/cooling load by using natural ventilation, orientation in right direction, etc. The university does work on thermal comfort using mannequins. One study looked at the thermal insulation afforded by the Arab clothing!

The other aspect of green buildings is the embodied energy aspect. This is the energy built into the material right from the source to use. Steel and aluminum have high embodied energy as also glass. While most renewable energy sources are available at the site, use of biomass is often criticised as it has high embodied energy, beginning with its origin as a crop requiring water right up to transport from faraway places!

“You need to balance out embodied energy with operational energy. The lifecycle cost of buildings and their components as also end of use costs that allow you to reuse materials when breaking down the building have to be weighed out,” says the professor.

The lifecycle aspect is also what is stressed by another expert, Melissa Vernon, director of sustainable strategy, InterfaceFLOR. She has worked at Interface Research where she created the corporate greenhouse gas inventory, bought renewable energy credits and assisted with a landfill gas direct-use project.
She also believes that project costs can be cut down if the greening begins at the start.