Located at Gual Pahari, just a few kilometres outside of Delhi's borders, Retreat is an example on how environment-friendly a building can be. TERI's building has used natural phenomena like sunlight, underground cellars, deciduous trees and micro-organisms to make Retreat a much-talked-about place, other than being the first building to be virtually inaugurated by the Prime Minister.

Retreat's use of solar panels for its heat and lighting requirement and the clever use of skylights, has cut down the complex's need for electricity by as much as 75 per cent. It also has no air-conditioning through machines and instead uses an underground air tunnel to cool all the 30 executive suites and conference rooms. Meant as a pilot project, Retreat is being thrown open to corporates to use as an alternative facility for their training and conference needs. However, TERI will make sure that the first half-hour session of the corporates' meet will be a lec-dem on Retreat and its unique features.

``We have to make sure that the people who are using the place understand the environment-friendly nature of the place and learn to be more appreciative of caring for the environment,'' says Ajay Mathur, director, TERI Energy Tech department. ``We have used all the local features of the area and the design and architecture had drawn from the hilly terrain to make the building sustainable,'' he says.

The building has a total energy savings of 184.25 KW per annum from an annual requirement of 280 KW. If TERI had purchased the power from the Haryana Electricity Board, it would cost it Rs 1.28 crore but the capital and running costs with the energy-efficient systems are down to Rs 1.18 crore. ``Though this may not seems as much of saving in financial terms, in the long run, we will recover the initial costs and the building will also contribute substantially to keeping the environment pollution-free,'' says Mathur.

Retreat does not use air-conditioners. Instead it has an air tunnel, 4 mts below the ground. ``The air 4 mts below the ground remains at a constant temperature, for Delhi this is about 25.6 degree C,'' says Mili Mukherjee, architect of Retreat.

The air tunnel runs below that building and using multiple speed blowers for better regulation of air flow, are sent into the rooms and conference halls. ``Even when the outside temperature was 43 degree C in Delhi, at Retreat the temperature was as low as 28 degree C. So, with a fan in the room, there is no need for any further air-conditioning in summers. In winters, the room temperature is again much higher than the outside temperature and the need for heating is eliminated,'' explains Mukherjee.

The water in the complex too is recycled. The water from the bath rooms is sent to a tank that has a natural plant, phragmytes, growing on top that have the natural ability to clean the water and the water that emerges from the other end of the tank is used for irrigation.

``In the rooms, we do not allow the guests to use clothes' detergents but body soaps and shampoos can be recycled by this plant,'' explains Mathur.The solar panels heat the water and are used for the lights. On rainy days on when the complex is full, TERI has installed a gasifier plant that uses wood use fire it. ``The wood pellets are made from the agro forestry part of the complex,'' Mathur explains.

Retreat is a completely sustainable habitat, and a living proof that self-sufficient energy is not a utopian ideal but a reality in brick and mortar. But is also an evolving experiment with TERI data-loggers keeping track of every part of the system. TERI hopes that in the years to come, people will pick up the sustainable ideas from TERI and implement it in their homes and offices.