green buildings
Green buildings use sunlight, water, energy and air more effectively. Sindh Building Control Authority needs to develop green buildings code for initiating a new area of green buildings. - File Photo.

The international conference on renewable energy held in Karachi on March 28 was informed that eight projects under implementation will add 325 megawatts of electricity to the national grid.

They comprise six wind turbines, two waste-to-energy projects, one hydroelectric and one solar energy-based power project.

While this is encouraging, electricity supply in Karachi is in a pathetic state. Currently, in Block 8, Clifton, two-hour loadshedding----- at 10am, 2pm, 6pm and at 10pm—make it a total of 8-hour of loadshedding out of 14 hours. In other words, the electricity is not provided for 57 per cent of the time from 10am to 12 midnight.

Luckily, there is a simple way of overcoming electricity crisis. All that is required is a change in the mindset, a rational strategic policy framework and a green buildings code.

Green buildings can save up to 60 per cent of electricity in view of the current electricity shortages in Karachi. Green buildings can also save potable water usage by 40 per cent.

Green building-- a practice of creating structures--- aims to reduce energy consumption, increase the use of renewable energy, and minimises production of waste. It has a marked edge over conventional (non-green) buildings.

Using electricity, water, natural resources and materials, conventional buildings cause water pollution, air pollution including indoor air pollution, land pollution (solid waste generation), heat islands effects, noise, odor and storm-water runoff problems.

The building sector is responsible for over 40 per cent of carbon dioxide emissions, ---- the principal global warming gas. Buildings account for over 50 per cent of energy use and, nearly 90 per cent of the electricity consumption.

In green buildings, electricity savings are achieved through a number of initiatives. Photovoltaic (PV) panels, which convert sunlight into electricity, can provide for over 20 per cent of the building's electricity demand. If a building has large uncovered area (large bungalows, industries, community halls), where more PV panels can be installed, it could meet over 50 per cent of the electricity demand.

Energy savers and sensors (devices shutting off light automatically, when a room is unoccupied), together can save electricity demand by nearly 20 per cent. Wind turbines convert wind energy into electricity. They can provide 10 per cent of the building's electricity demand. In Karachi, due to high winds, especially in the belt along the coast, these devices can provide for over 40 per cent of the electricity demand of a building.

Insulation or light-colour painting of roofs and the use of plantations and trees keep rooms cool, reducing the demand of electricity for air-conditioners. Thermostat temperature requirements become low. Together, they save about 10 per cent of electricity.

Thus, nearly 60 per cent of electricity can be saved, if the green measures are adopted. In Karachi, this translates to saving of nearly 1,500 MW of electricity - enough to get rid of the current problems of loadshedding, or, if the KESC supply is managed judiciously, outright saving of electricity.

According to a rough estimate, an average-sized green building can lead to the following annual emission reductions: 1,200 pounds of nitrogen oxides, 150 pounds of particulate matter, 1,300 pounds of sulfur dioxide and, 585,000 pounds of carbon dioxide. Global warming, climate change and the resulting increased severity of hurricanes, sea-level rise, increased heat-related deaths, accelerating environmental degradation and species extinction, can cause damages in billions.

Another major achievement of green buildings is the water conservation. Its strategies in green buildings are wide-ranging, which can lead to as much as 40 per cent saving of potable water. Some of the strategies include use of low-flush toilet tanks (five-litre flush tanks, as against the present 11 litres); shower heads with flow regulators (reduces pressure with which the shower is splashed); faucet aerators (water from taps pass through a gauze, causing air to enter into water.

The mixture of air and water reduces the volume of water delivered; spring taps; ban on use of hose pipe connected to water pumps for washing cars; control of water overflows from overhead tanks; reuse and recycling of reclaimed water in industries; use of grey water or sullage (water from kitchens, bathrooms and washing machines) for washing and gardening; leak control; and rainwater harvesting.

The options, green buildings use for waste reduction, are many-fold and include aspects like, reuse and minimisation of building debris; use of building materials more durable and easier to repair; design to generate less scrap material through dimensional planning; use of reclaimed building materials; development of indoor recycling programme; and design for deconstruction. Together, these strategies can have a dramatic impact on waste reduction. Waste reduction rates in green buildings are typically 50 to 75 per cent.

Green buildings consider indoor environmental quality, in details, since, people spend 90 per cent of their time indoors. The building occupant's health, comfort and productivity dependent largely on indoor environments. Four attributes are associated with green building design: ventilation, temperature and lighting control; and day-lighting.

Proper design and consideration lead to the following benefits: low emitting sealants, adhesives, paints, carpets and composite wood; indoor chemical and pollutant source control; better lighting quality; more day-lighting in buildings; reduced health problems (respiratory illness, allergies, asthma, sick building syndrome) and; occupant's control over temperature, light and glare.

Noise is managed through careful site choice such as finding a property that is isolated from busy roads and industry. Good design can also assist in managing external noise impacts.

While there would be about two per cent increase in construction costs of green buildings, the operation and maintenance costs are reduced by 20 per cent. Minimal increases in upfront costs of about two per cent to support green design would, on average, result in life-cycle savings of 20 per cent of total construction costs - which is more than ten times the initial investment.

Green buildings use sunlight, water, energy and air more effectively. Sindh Building Control Authority needs to develop green buildings code for initiating a new area of green buildings.