DECARBONISING CITIES THROUGH GREEN AND ENERGY EFFICIENT BUILDINGS
DECARBONISING CITIES??THROUGH?GREEN AND ENERGY EFFICIENT BUILDINGS
?*Jit Kumar Gupta; [email protected]
Introduction
Historically, cities are valued for the contributions they maketo promote economic development, generate employment, promote innovations and provide options for state of art infrastructure and facilities. Housing large human numbers, cities ?also remain preferred location for operation and ?concentration of activities.Cities not only create, generateand provide supportive environment for businesses to thrive and flourish, but also enable residents to have gainful employment and quality of life. Cities invariably drive competitiveness and investments.Studies made by UN indicate that, cities globally housed 4.2?billion people, or 55 percent of the world's population in 2018. By 2050, the urban population is expected to reach 6.5?billion. Accordingly, cities will script the future of communities and nations. Despite ?showcasing distinct advantages, cities are known for their dualities?and contradictions; ?positivities and negativities. Occupying merely 3% of the area of planet earth and generating 60% of the global wealth, cities are known to consume 70% of the energy, generate 75% of the carbon footprints and ?produce 70% waste; indicating that if cities are?usherers of the?global/nation’s prosperity, they are also responsible for promoting global crisis and growing vulnerability in terms of rising temperature, ozone depletion and ?increasing ?carbon footprints. Reckoned to be prime cause and ?major victims of??disasters striking the planet earth ,cities are fast becoming vulnerable and unsafe. Two major factors ?considered ?largely responsible for making cities hotbeds of global warming and ever-increasing carbon footprints include; irrational ?manners in which?built environment is being created and the manner in which people , goods and services are ?transported. Buildings are ?known to be primarily responsible for consuming large proportion?of energy, electricity, water and materials. Studies made and analysis carried out by International Energy Agency , has estimated that existing buildings are responsible for more than 40% of the world's total primary energy consumption and?24% of global carbon dioxide emissions. Accordingly, in order to decarbonize the cities, ?there is an urgent need for not only ?designing and constructing our?buildings, more rationally and thoughtfully; but also ?minimizing the??travel ?and traffic, to ??make cities sustainable and carbon neutral.
Buildings/Built Environment
Human growth and built environment have close connectivity and high degree of inter-dependence; because historically, built environment has scripted and showcased the footprints and achievements ?of humanity, right from its inception. All human activities of living and working, ?require built environment for?optimisation. Buildings?also ?remain relevant and valuable for saving, protecting and ?providing shelter ?to human beings from the vagaries of nature; including extreme heat, extreme cold, precipitation, snow , wind , thunderstorm, cyclone etc. With 80% of human life spent within four walls of buildings, built environment remains major determinant of quality of human living. In addition, buildings significantly impact?environment, ecology, bio-diversity; consumption of resources. Known for dualities and contradictions, buildings not only provide space for productive?human living , but also considered anti-thesis to the environment and ecology. Buildings constitute a complex system of designing, construction, materials, resources and environment.
According to, ‘World Energy Council Report,2016’, Buildings consume over40% global?energy, 30% raw materials, 25% timber harvested, 16% fresh water withdrawal, generate 35% of world’s CO2 emission, 40% municipal solid waste and 50% ozone depleting CFC besides promoting ‘sick building syndrome’. Looking at the entire context that buildings are the largest consumers of energy and resources, they also offer greatest opportunity to minimize energy consumption, by simply changing the options used for planning, construction and operation of the buildings.?If sustainability is not embedded into ?planning, designing and construction practices, building related emissions could double by 2050( UNEP ).
Green?Buildings
Looking at the entire gamut of built environment, Green Buildings emerge as the best option to make buildings sustainable and least consumers of energy and resources. Green Buildings minimize use of water, optimize energy efficiency, conserve natural resources, generate less waste and provide healthier space for occupants as compared to conventional buildings. Green buildings, as a concept, approach and strategy to decarbonize?the cities, has been gaining acceptance?among professionals and users for its distinct advantages.
?Considering the multiplicity of components involved, Green buildings have been defined differently and distinctly, by different experts, institutions and agencies involved in planning, designing and constructing such buildings.
·??????World Green Building Council has defined Green Building as a, “Building that, in its design, construction or operation, reduces or eliminates negative impacts, can create positive impacts, on our climate and natural environment. Green buildings preserve precious natural resources, improve quality of life.
·??????Jerry Yudelson, describes, Green Building, as a high-performance construction that reduces its impact on the environment and human health. (Yudelson, Jerry, 2008).
·??????As per. The?Indian Green Building Council?(IGBC) ,‘A green building is one which uses less water, optimises energy efficiency, conserves natural resources, generatesless waste and provides healthier spaces for occupants, as compared to a conventional building’.
·??????USGBC says, ‘Green building is a holistic concept that starts with the understanding that the built environment can have profound effects, both positive and negative, on the natural environment, as well as the people who inhabit buildings every day. Green building is an effort to amplify the positive and mitigate the negative of these effects throughout the entire life cycle of a building
Looking at the entire context, Green Buildings are characterized by distinct features involving;
·??????Efficient use of energy, water and other resources
·??????Using renewable energy including solar energy
·??????Minimizingpollution and waste through re-use and recycling
·??????Promoting ?healthier spaces, good indoor ?environment and ?air quality
·??????Using non-toxic, sustainable and waste based , local materials
·??????Involving environment in design, construction and operation
·??????Designing with nature using natural elements
·?????Valuing and including user’s quality of life in design, construction and operation.
?Benefits of Green Buildings
Globally, green buildings?are being recognized and valued, for bringing multiple benefits and?providing best option for achieving Sustainable Development Goals , addressing climate change, reducing global warming, creating sustainable & thriving communities, and driving economic growth. Using less water, energy or natural resources, Green buildings not only reduce/eliminate negative impacts of buildings, but also positively impact environment by generating their own energy and increased bio-diversity. Globally, green buildings have capacity to reduce greenhouse gas emissions by 35%;?energy savings by 50%, water consumption by 40% and?limiting global temperature rises to 2°C by 2050 (UNEP). Green Buildings can also discount Co2 by 8000-12000 tons and3 MW of connected electric load for every million sft. of built space; besides reducing 70% waste. Green buildings not only reduce consumption of non-renewable resources but also ?offer numerous economic/ financial benefits such as, lowering construction ?and operating costs, ?increasing property values; increased occupancy rates; ?and generating more employment opportunities. Social benefits of green buildings?include; better health and wellbeing of people; increase in cognitive scores; sleeping about 46 minutes more per night?and improving performance?upto 8 %. ?(Dodge Data & Analytics, 2016 ) . Studies made have also revealed ?that, ‘Green Schools?make learning easy and?more meaningful’; ‘Green Houses makes people happy and healthy, and Green Hospitals cure patients quickly. Green buildings may cost more up-front, butsave through lower operating costs over useful life of building. Cost saving is optimised, when buildings are designed as green buildings at the conceptual design phase. Potential financial benefits of improving indoor environments exceed costs by a?factor?of 8 and 14.Green Building practices expand/ complement building design concerns of: economy, utility, durability and comfort.
Designing Green Buildings
On the threshold of massive urbanisation, propelled by large population base, high natural growth rate?and ever increasing rural-urban migration , built area ?requirements of ?Urban India are rising sharply. As per, McKinsey Global Institute Report,2010, ‘India would be required to create buildings to the tune of 700-900 million sqm, on annual basis, ?to meet the needs of housing and Business, for additional population in urban India’. Requirements of energy, materials and resources for construction and operation of such a huge volume of buildings will be enormous. Accordingly, building, as a sector, would require close scrutiny and monitoring for effecting and achieving overall economy in energy consumption, use of resources and generation of waste, for making buildings green and sustainable.
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Designing with Climate
Architectural designs are known for their capacity and hold the key to promote sustainability in the built environment. Accordingly, sustainability needs to be made intrinsic and integral part of all Architectural designs for making buildings sustainable and green .Any building can be designed as a?green building, whether it’s a home, office, school or a hospital. However, all green building designs don’t follow uniformity and similarity. While principles for building green remain universal but?designing?green buildings will vary from region to region and within regions, depending upon?prevailing climate, site conditions, building typology and prevailing wide-ranging environmental, economic and social priorities. Green Buildings shall invariably be designed based on the climatic conditions prevailing at the regional/city/local levels. Based on the climatic conditions, India has been divided into five instinct climatic zones including, Hot and Dry; Warm and Humid; Composite; Temperate and Cold& Sunny. Since climatic conditions of temperature and humidity varies in all these zones , accordingly, building design shall vary in each zone. If in the Hot zone, green buildings will try to eliminate all options of heat gained by the building and in case heat is gained, building is designed to promote heat loss in the minimum timeframe, in order to maintain the indoor temperature at comfort level. However, in the case of Cold climate, building designs are oriented ?to capture maximum sun so that solar heat can be optimized to keep the indoor spaces warn and comfortable, without resorting to mechanical heating.
Adopting Integrated Approach;
Experience has shown that buildings can be designed to meet the occupant’s needs for thermal comfort at reduced level of energy consumption by adopting an integrated approach to building design. The integrated approach would include rational site planning; determining optimum shape and size of the building ;minimising floor to volume ratio; promoting ?building efficiency; rationalising ratio between length and depth of the building; using simple?structural form; promoting high degree of energy efficiency; optimising water efficiency and minimising use of water; using low embodied local materials and material made from industrial/agricultural waste; using principles of solar passive building design; using energy efficient equipment for lighting, heating, ventilation; using solar energy?for meeting the energy/lighting/heating of building and generating energy from non-conventional sources.
Designing with Orientation
Orientation is the most critical factor which needs to be effectively leveraged in all building design to evolve energy efficient building envelop, by making use of solar light/heat/radiation and the wind energy. However, requirements of building design would vary, from region to region, based on prevailing climatic conditions.?Accordingly, buildings with regard to sun and wind will have to be oriented differently in different regions. In order to ensure that building design makes best use of solar and wind energy, it would be essential that majority of building sites should have the advantage of?best orientation. Accordingly, role of town planning assumes importance, for ensuring that highest consideration in planning is given to orientation so that maximum number of plots has the advantage of best orientation. In addition, ratio of plot width and depth needs to be fixed so that the entire depth of?built-up area ?should have access to natural light during the day, minimizing the requirement of artificial lighting. This would be particularly important, in case of row housing where plots have the option to draw light ?only from front and rear .
Designing with Nature
Genesis of green buildings shall always remain nature centric. Accordingly, planning and ?designing of green buildings shall ?invariably be based on ?using?design options which remain nature ?centric and make optimum use of available?natural elements/sources and vegetation, for meeting entire needs of heating, lighting and ventilation of the buildings. Planning with nature would essentially involve, making optimum use of Panchbhutas- Prithvi (site), Agni( energy), Jal (water), Vayu (air) and Aakash (Space), for meeting the basic needs of energy and?resources for buildings. Any building designed with nature shall always remain a sustainable and green building. Ignoring and excluding nature from?designing, shall never make any building green. Nature based design helps in making buildings not only?sustainable but also promoter of wellbeing of the users besides making value addition to the place and environment ,where such buildings are placed and positioned.
Space Planning
Space planning is another mechanism to promote green buildings and making them sustainable because each site has positivities and negativities. In the hot regions, western side remain the most unsustainable, whereas south and south- east direction are considered better?for human living. Accordingly, positive and negative directions need to be mapped?considering the movement of sun and?wind. While planning the buildings, all spaces used for human habitations??should be placed in good orientation and all spaces requiring minimum human habitation, can be placed on orientation not conducive to human living. This approach can help in minimising the energy consumption and making available habitable spaces in the best Planning for?Life Cycle Cost;
With?only 10% cost going into initial construction and 90% cost going into?operation and maintenance, planning and designing buildings based on?lifecycle cost will be the best option for making buildings?sustainable. Green buildings, accordingly focus on minimizing life-cycle cost of buildings by reducing and optimising energy, water?and resource consumption for creating?win-win situation for both owners, builders and occupants over the entire life span of building.
Energy efficiency
Green buildings are designed to achieve highest degree of energy efficiency through?thermal insulation, installing high performance windows, using passive heating, ventilating and air conditioning , geo-thermal options besides using day lighting ?as integral part of designing process.
Water efficiency; Green buildings optimise water efficiency by using water efficiently and reducing water consumption by;?slowing the flow; multiple use of water; recycling and reuse of water; mixing air with water; using water-efficient fixtures; rain water harvesting; and minimize storm water runoff.
Design efficiency; is achieved by making Green buildings compact with smaller footprints, using space more efficiently, achieving highest carpet area,?minimising circulation /area under walls, adopting efficient structure and structural?system,?minimizing construction waste.
Promoting high indoor air quality; by choosing environmentally responsive non-toxic/low VOC based materials and finishes, for construction/interior finishes, produced by clean manufacturing processes that do not pollute and produce unhealthy interior environments.
Using materials; in natural form which are available locally, cost-effective, having low embodied energy , produced from ?industrial/agricultural waste and are easy/inexpensive to repair and maintain
Retro- Fitting of existing Buildings
?In addition, to making new buildings green and energy efficient, it will also be critical that concerted efforts should also be made to make existing?buildings energy/resource efficient and carbon neutral. Retrofitting the existing buildings has ?been used as the mechanism to make building green and cities sustainable. Singapore has?drawn a master plan to make all the existing buildings green through a collaborative policy framework involving residents, property owners and the government. Retrofitting of Empire State Building of New York has led to achieving reduction of electricity load for the building to the tune of 3.5 MW and greenhouse gas emissions by 1,00,000 tonnes over a 15 years period. The payback/recovery period for the $13.1 million spent on retrofitting of building, has been placed at 3.5 years due to saving in energy, lighting, air conditioning etc. Retrofitting needs to be promoted on large scale to make cities sustainable.
Conclusion
Green Buildings, as a concept and strategy,is now being increasingly adopted globally and locally, to make built environment affordable, sustainable and resource efficient. Considering the enormous amount of built environment yet to be created, urban India will have no option but to tread the path of sustainability and sustainable development in the built environment to promote economy,?generate employment, banish poverty and restoring balance in environment and ecology. Sustainable built environment would go a long way in achieving, majority of the 17 Sustainable Development Goals for the reason, built environment is known to be the largest consumer of energy, resources and generators of waste. Urban sustainability will ?be?largely?contingent upon?how effectively and efficiently buildings are made green??using renewable/waste materials and involving state of the art options for?designing, construction and operation. Green building design practices, reduce the?environmental impact ; minimize building footprints; promote energy conservation, sustainability and resource efficiency by focusing on?environmentally sound methods of design and construction.?Employing more than 35 million people (1/6 of total workforce of country),India’s construction industry is projected to expand, both horizontally and vertically, with investments in residential, infrastructure and energy projects continuing to drive growth. Various government flagship programs; including 100 Smart Cities Mission, Housing for All, Atal Mission for Urban Rejuvenation and Transformation (AMRUT), Make in India; Power/water for All; Making India$ 5trillion economy, Carbon neutral by 2070 and Putting 500GW of non-conventional resource-based energy by 2030; will be the major growth drivers for the construction/building industry. Growth agenda of the Government of India offers both a challenge and an opportunity, for ?the professionals and building industry. Considering the major implications of buildings, it will be?important?that ?construction industry must innovate and evolve, so that built environment created in future is more affordable and sustainable. Failure to make built environment sustainable will have huge environmental, financial, economic, physical and social implications for people, community and nation, which will be difficult to resolve and rationalise subsequently.
?Bibliography
·???????The Future of Construction Sector in India,?Build Tech Magazine India -?September 9, 2016
·????????Walker Wells, Ed, Blueprint for Greening Affordable House, Washington: Island Press, 2007, pp 2
·???????Alpana Sivam and Sadasivam Karuppannan; The Sustainability of Affordable Housing ,University of South Australia
·???????McKinsey Global Institute: “India’s Urban Awakening: Building Inclusive Cities, Sustaining Economic Growth”, April 2010
·???????World Green Building Council;https://www.worldgbc.org/what-green-building
·???????Wikipedia;Green Buildings; sustainable construction principles.