Not many people know that the building sector is the third largest consumer of energy after agriculture and industry. About 1/3 of all energy related carbon emissions come from the building and construction sector. The design, construction and maintenance of buildings have a tremendous impact on the environment and natural resources. Typically buildings consume about 1/6 of world’s fresh water withdrawals, 1/4 of wood harvested and around 1/3 of solid waste generated. In today’s world of climate change, high energy prices, water stress and rampant deforestation, it is critical to build green and smart. Green buildings should include both mitigation and adaptation strategies if we hope to reshape the built environment that is responsive and resilient to future climate change requirements.
Experts on climate change say the building green is one of the least-cost approaches for mitigating climate change. Green buildings optimise energy efficiency, use less fresh water, conserve natural resources, produce minimum of pollution, produce lesser waste, and provide healthy living spaces for occupants as compared to conventional buildings. Applying a life-cycle cost analysis, the concept of green building examines the performance of buildings starting from extraction of raw material and tracing all operations until their final disposal as wastes back into the earth. Energy required to extract, transport and manufacture various building materials like cement, paints, insulation, plumbing & electrical material, etc are all tallied in sum total of energy which is called as ’embodied energy’ of the building. Green building is becoming popular both among builders and occupants and the Green Council of India has around 1700 eco-friendly building projects registered with it covering around 1.2 billion sq ft of green building footprint which is expected to increase to nearly 2 billion sq ft by 2015.
Says Panaji-based architect Milind Ramani who specialises in conservation architecture “Climate has always been integrated into the building profession with building practices typically assuming that the future will be similar to the past, however with climate change builders have to plan for a range of uncertain futures. Earlier building decisions were based on historic climate data, but today building profession have to consider climate change projections along with historic trends to arrive at their design, construction & maintenaace decisions. Building professionals say that though green buildings may cost around 3-5% higher than conventional buildings, it gets paid back within a short period of time due to reduced operational & maintenance costs which continue throughout the lifespan of the buildings.
Green building functions as a least-cost mitigation strategy mainly through energy efficiency. All elements of a building – be the foundation, framing, roof structure, window panes, etc have huge energy saving potential. Energy used inside a building is the second tier for energy saving potential. Potential energy savers include optimal interface with electrical grid, mechanical equipment sized to the actual load of the building, optimum natural day lighting and ventilation which greatly impact the amount of energy used inside the building. All these elements need to be considered in the early design stage to maintain cost effectiveness. In the West, much investment is put into retrofitting older building due to the compelling evidence that day-lighting greatly improves ventilation and saves much on heating & air-conditioning.
Green building movement has spread worldwide and countries across Asia, Europe, North America and Australia have adopted some form of green building. India currently has two voluntary building rating systems: 1) LEED INDIA (Leadership in Energy & Environment Development) run by the Indian Green Building Council and focussing on energy-efficiency measures in air-conditioned buildings, and 2) GRIHA (Green Rating for Integrated Habitat Assessment) which is a National Rating System developed by TERI and Ministry of New & Renewal Sources of Energy. Since 2007 Bureau of Energy Efficiency has launched Energy Efficiency Building Code applicable for all commercial buildings with minimum conditioned area of 1000 sq mts and a connected power demand of 500 kw or 600 KVA. The energy performance index under the Code is set from 90 kwh/sqmt/year to 200 kwh/sqmt/year and any building falling within the index is termed as EFBC Compliant’. If fully implemented the EEBC can save around 35-40% of energy in buildings say energy efficiency experts.
India has vast scope in adopting green building as mitigation & adaptation mechanism against climate change. Massive funds have been earmarked for improving basic services & infrastructure in 60 major cities under Jawaharlal Urban Renewable Mission as well as for Sustainable Habitat Mission under the National Climate Change Action Plan. Considering high urbanisation rates, need for providing housing for millions of people, specially the urban poor, there is considerable scope for climate-friendly built environment, which in turn will open wide opportunities in green construction, engineering design, green building material, equipment like low-emission windows & paints, smart roofs, high-efficiency heating, ventilation & air-conditioning systems, water-saving systems, etc.
However, despite great potential several barriers impede popularisation of green building. Currently green building is some sort of an elite standard and there is widespread lack of awareness allied to which is lack of incentives like additional floor space index (FSI), rationalisation of property tax and electricity tariffs, reduction of state taxes like VAT on green building technologies, etc. Presently the grading systems are voluntary and Energy Efficiency Building Code is not strictly & fully implemented. There is widespread myth that green building is very expensive. Acutally green buildings now cost not more than 3-5% more than conventional buildings, and the savings over the lifespan of the building is substantial, which fact needs to be widely disseminated among builders and public alike.