Buildings offer a huge opportunity to minimize energy consumption by merely changing the manner in which they are planned, constructed and operated.
Jit Kumar Gupta, Retired Urban Planner, Advisor Town Planning, Punjab Urban Development Authority.
Buildings remain central to all human living because 80% of human lifespan is spent within the four walls of a building envelop. Modulating quality of life, buildings make human beings healthy or sick. Considering the large amount of energy and resources consumed, buildings are also considered as major polluters of the environment and generators of large carbon footprints. Accordingly, buildings remain responsible for climate change, global warming, and modulators of sustainability. Making buildings sustainable is essential for preserving, protecting, and making value additions to resources, environment, and the ecology.
India is going through rapid and massive urbanisation. The McKinsey Global Institute report ‘India Urban Awakening: Building Inclusive Cities’ has estimated that 700-900 million sqm of built space would be required annually to meet the needs of urban India. Considering the large consumption of resources and generation of waste in urban India, the enormity of space and the implications as consumers of energy and resources, buildings need to be planned, constructed, and operated with a focus on energy conservation, sustainability, and resource efficiency
Buildings constitute a complex system of designing, construction, materials, resources, and environment. Revolving around seven layers during its life-cycle (siting, designing, construction, operation, maintenance, renovation, and deconstruction); promoting consumption (energy, water, materials and natural resources); impacting environment (generating waste, air / water pollution, indoor pollution, heat islands, storm water runoff); buildings can adversely impact human health, environment, and precious resources.
According to the World Energy Council Report 2016, buildings consume over 45% global energy, 30% raw materials, 25% timber harvested, 16% fresh water withdrawal, 35% of world’s CO2 emission, 40% municipal solid waste, and 50% ozone depleting CFC, besides promoting ‘sick building syndrome’.
Considering the lifecycle cost and energy, only! 0% cost and 17% energy goes into the making of a building, while the remaining 90% cost and 83% energy are used in their operation and maintenance, involving heating, cooling, lighting and ventilating. Thus, buildings offer a huge opportunity to minimize energy consumption by merely changing the manner in which they are planned, constructed and operated.
Looking at the gamut of the built environment, Green Buildings emerge as the best option to make buildings sustainable and the least consumers of energy and resources. Green Buildings minimize use of water, optimize energy efficiency, conserve natural resources, generate less waste, and provide a healthier space for occupants as compared to conventional buildings. Green Buildings save energy up to 50%; water consumption by 40%; reduce carbon emission by 35%; CO2 by 8000-12000 tons, and 3 MW of connected electric load / million sqft; besides reducing 70% waste.
Green buildings not only reduce consumption of non-renewable resources but also fetch better returns. They provide financial, environmental, and social benefits - creating a win-win situation for both the owners and the occupants through improved productivity. Studies reveal that Green Schools make learning easy and more meaningful; Green Houses make people happy and healthy; Green Hospitals cure patients quickly; and Green Shopping Malls can increase sales and profits.
Green building may cost more upfront but they save through a lower operating costs over its life. Cost savings are optimised when buildings are designed as green buildings at the conceptual design phase. Potential financial benefits of improving indoor environments exceed the costs by a factor of 8 and 14. Green Building practices expand and complement building design by factoring in economy, utility, durability, and comfort.
The World Green Building Council has defined a Green Building as a building which in its design, construction, or operation, reduces or eliminates negative impact, and creates a positive impact on the climate and natural environment, while preserving the precious natural resources and improving the quality of life. Green buildings have the following features:
- Efficient usage of energy, water and other resources
- Use renewable energy including solar energy
- Reduce pollution and waste, re-use and recycle
- Promote good indoor environmental air quality
- Use non-toxic waste-based sustainable materials
- Value environment as an integral part of design, construction, and operation
- Ensure quality of life for occupants
- Evolving design that responds positively to the changing environment.
While the design principles for green buildings remain universal, however, their design will vary from region to region and also within regions, depending upon the prevailing climate, site conditions, culture, traditions, available materials, construction practices, and building typology, besides the environmental, economic, and social priorities.
A green building not only minimises the use of resources but also replaces the conventional resources with resources that are available in abundance and are regenerative. The basic design approach revolves around designing with nature, making best use of natural resources, and adopting an integrated approach to design. While planning with nature essentially involves 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, an integrated approach to design would essentially revolve around respecting the site, rationalising site planning, rationalising the built form, lowering surface to volume ratio; promoting building efficiency, evolving efficient structural design; adopting solar passive techniques, using energy efficient equipment, controlling lighting, heating, ventilation; using solar energy/air movement, reducing transportation, minimising waste, using local materials in their natural form, optimising landscaping etc.
A building’s orientation will be the determining factor when using natural resources, and, accordingly, will be effectively leveraged in the design solutions so as to modulate heat gain/loss and create an energy efficient building envelop.
Since the requirements of building design would vary with regard to the climate, sun and wind, they will have to be oriented differently in different regions. For ensuring that buildings will make the best use of solar and wind energy, the building sites should have the best orientation.
Accordingly, the town planner’s role would be to ensure that the maximum number of plots have the best orientation so that the architects can create a sustainable and energy efficient design. Rationalising site planning would ensure that the entire built up area shall have the benefit of natural light during the day. This would be particularly critical in case of row housing, where plots have the option to draw light only from the front and rear. For making buildings energy efficient, they must be designed to conform to the norms and standards defined by the Indian Green Building Council.
Considering the lifecycle operations, buildings consume two types of energy - embodied (which goes into their making) and energy used in various operations and maintenance (HVAC and lighting) during their lifespan. Only 20% energy is used during construction whereas O&M operations involve 80% energy. Accordingly, to make buildings energy efficient, both embodied and operational energy components will need to be reduced.
Reducing embodied energy will require optimizing various systems; reducing structural loads; using low-energy construction technologies; creating resilient and flexible structures; using local/natural/low energy materials in natural form including debris, etc.
Orienting buildings properly and adopting passive/climate responsive design strategies; placing habitable rooms in best orientation for harvesting optimum heat and light; sourcing natural light through positioning of windows, avoiding glare, using minimal glass on east/west, applying light colours for roofing /wall finish materials, installing high R-value wall/ceiling insulation, etc will go a long way in reducing operational energy demand of buildings.
Using properly sized, energy-efficient and rated lighting/heating/cooling systems in a thermally efficient building shell will be a pre-requisite to make buildings green. In the past, the strategy has been to make buildings energy efficient, which needs to be taken to the next level of zero energy buildings (SDGs) before achieving the ultimate objective of making buildings energy positive. This would need a dual strategy of minimizing energy consumption and making building net generator of on-site renewable energy from natural resources (sun, wind, bio-mass, geo-thermal). It would also involve daylight harvesting; promoting operational / maintenance efficiency through BMS (Building Management System); smart metering besides computer modelling (for optimizing design of electrical/mechanical systems and building shell), along with using advanced lighting controls (motion sensors / dimmable lighting controls etc) for making buildings smart and energy efficient.
Having merely 4% of world’s water resources for supporting 17.3% of world’s population and 20% of world’s livestock (500 million - Gangwar 2013), India remains one of the most water stressed nation globally. Despite limited availability, India uses the largest amount of ground water (24% of global total), more than that of China and USA combined. India is the third largest exporter of groundwater 12% (Water-Aid). India currently ranks 120 among 122 countries in the water quality index. According to NITI Aayog, “India is suffering from the worst water crisis in its history, and millions of lives and livelihoods are under threat.” Critical issue of water is demand on supplying aquifer/sources exceeding ability to replenish it. At least 21 Indian cities, including Delhi, are estimated to run out of groundwater, affecting millions of people by the next decade.
Buildings are large consumers of water during its lifecycle, including building operations, producing materials used in construction, curing, and in their operations and maintenance. The building sector is estimated to consume 16% of total freshwater withdrawal globally. However, Green buildings remain highly water-efficient, reducing consumption by up to 40%. So, for making construction sector water-efficient, green buildings shall be the best option.
An effective water management should revolve around fourfold strategy: protecting water, conserving water, protecting water quality, and reducing consumption. Options for minimizing water consumption shall involve; adopting water-efficient construction practices. Pre-fabrication technology, known for its water efficiency, needs to be leveraged more effectively.
The strategy for multiple uses of water through dual plumbing; in-house sewage treatment; using phytometric solution for sewage treatment; using grey water for flushing and landscaping; using water rated/efficient fixtures like ultra-low flush toilets/urinals; rationalizing landscaping; using native flora and fauna; minimizing building footprints; providing large porous space etc can lower water consumption and increase ground water recharge. The intent is to reduce the generation of waste-water and potable water demand.
Slow the flow, breaking water flow, creating mist by mixing air with water, are other options to reduce water consumption. From water efficiency, there is need for buildings to graduate to zero-water buildings, and ultimately become water-positive buildings by promoting rainwater harvesting, ground water re-charging, air based cooling, and reinventing a sanitation system which is not simply water-based.
Using Green Materials
Buildings consume three billion tons of raw materials annually, constituting 40% of total materials used globally (Roodman and Lenssen, 1995). Materials remain major determinants of embodied energy, cost, quality, and maintenance of buildings besides posing serious environmental issues associated with extraction, transportation, processing, fabrication, installation, reuse, recycling, and their disposal. Considering their major implications, materials used in buildings should promote conservation of non-renewable resources; ensure energy conservation; minimise maintenance/replacement costs; create healthy indoor environment; lower the costs associated with making additions/alterations, besides offering greater design flexibility.
Accordingly, materials used in buildings should essentially be resource efficient; natural, plentiful, renewable; energy and water efficient; environment responsive; affordable; require minimum maintenance; recyclable; locally available; easily salvaged, refurbished and remanufactured; made from industrial/agro waste, and durable. Further materials should be lightweight to reduce the self-load of the building, using using fewer and more durable materials and generating less waste at the end. In addition, green buildings should use innovative construction technologies which are cost- effective, material efficient, speedier, energy/water efficient, safe, generate minimum waste, use local resources, ensure optimum use of materials, and integrate renewable and low-carbon technologies.
Improving Indoor Air Quality (IAQ)
With cost, quality and time becoming important, indoor air quality, despite its importance, remains the most neglected aspect of building design since human beings spent 80% of their life span within a building. Good IAQ reduces fatigue in occupants; fosters better health, and improves work performance, and optimizes living conditions by avoiding CO2 concentration. A poor IAQ is the result of materials and finishes used in interior and exterior of buildings; poor ventilation; chemical emissions; lack of natural light; smoke/dust; moisture etc. As a major determinant of IAQ, materials selected should be non-toxic; have minimal chemical emissions; have low-VOC assembly: be moisture resistant and easy to maintain, and use indoor plants. Promoting good IAQ in a building would require a temperature range of 21 - 24oC, relative humidity (RH) below70%; CO2 levels < 1000ppm; exclude VOC with vapour pressures limited to restrict the fungal/ microbial/ pathogens growth; natural daylight, outside views, good landscaping, and efficient ventilation.
Globally, green buildings have the capacity to reduce greenhouse gas emissions by 84 GtCO2; energy savings of 50%; and limit global temperature rises to 2°C by 2050 (UNEP). Green buildings offer numerous economic/ financial benefits-due to their lower construction costs, higher property value; increase in occupancy rates, and lower operating costs. Green buildings are known to command 7% increase in value over traditional buildings; workers in green offices record 101% increase in cognitive scores (brain function), sleeping 46 minutes more per night with increased productivity of 8%.
Green Buildings remain best the option for achieving global SDGs; addressing climate change; creating sustainable/thriving communities; driving economic growth ensuring environmental, economic and social benefits; minimising waste and maximising reuse; promoting health and wellbeing and creating a win-win situation for owners, occupants, communities, and nations.
Considering the massive urbanisation and growing needs of the built environment, India must immediately put in place an effective/efficient policy framework to retrofit the existing buildings and make all new buildings net- zero carbon by 2050, on the pattern suggested by World Green Building Council, to make a Sustainable India.
- World Green Buildings Council; What is a Green Buildings; https://www.worldgbc.org/what-green
- Woolliams Jessica; Planning, Design and Construction Strategies For Green Buildings; British Columbia Buildings Corporation Ministry of Finance and Corporate Relations; July, 2001, http://www.greenbuildingsbc.com
- Sharpe Tim; The Role of Building Users in Achieving Sustainable Energy Futures; October 3,2012
- Dick Greg; Green Building Materials;: https://www.calrecycle.ca.gov/GreenBuilding/ ; October 18, 2019
- Asian Development Research Institute-India Water Facts-https://www.adriindia.org/adri/india_water_facts\
- All images are sourced from Google-search; which are gratefully and thankfully acknowledged and appreciated