Measures to make cities sustainable in the long term
Beyond the rating systems for green buildings, city administrators and urban planners have to look at very simple set of measures that they can implement by legislation. They should try securing voluntary compliance from end/users, as India has attempted, with public awareness campaigns that exhort the practice of energy-efficient management. Our experience in India has been that voluntary compliance, not surprisingly, does not work half as effectively as mandatory compliance.
The following measures will make a difference. They are easy to implement, affordable, and do not need any complex technical support for securing compliance.
(a) Installation of aerators and flow restrictors in every faucet and shower of every building, old or new, in a city. A home of four people can save as much as a staggering 30,000 liters a year of fresh water by this simple installation. These can be installed for existing fixtures of old buildings as well as, of course, for new buildings at a cost not more than Rs 3000 for a house with two washrooms. They are easy to fit for old or new faucets, cost so little, and cause no discomfort or inconvenience for the user when s/he turns on a tap.
A city of 100,000 households will save as much 10 million liters a day on this one measure alone. Remember, solution for water deficiency is not water generation but water efficiency.
(b) A ban on the use of halogens, metal halide bulbs and such high-energy consuming lighting appliances. This will bring sharp saving in the demand for energy from particularly the commercial sector, of as much as 50 per cent.
The installation of CFL bulbs in every home, of an average size of 1000 sq. ft., can save 70 per cent on the lighting part of the bill alone. This means that for every 2000 houses, of average size, one million units of energy will be saved every year by the city. That is small by energy but by industry terms it adds up. If the current number of households is about 100,000 you can see that this will mean a saving of as much as 50 million units per annum for the city!
Every unit saved is equivalent of ten times in terms of energy generation thanks to the losses in transmission and distribution in any electrical distribution system.
With today’s cost of energy generation being over US$1 million per megawatt for hydel generation systems, (it’s USD 2.5 million for nuclear), any country will benefit hugely from such a drive to save energy.
India has demonstrated the success of such initiatives in few cities although there is a great deal to be done in the vast and complex systems that the country has to deal with. Bangkok as a city has also managed to achieve such success in energy efficiency and savings.
(c) A city can benefit from the ban of electric geysers and the installation of solar collector panel-based water heating systems. For a typical household, the cost is no more than Rs 30,000. At the current energy tariff, the payback or amortization of the investment can be secured in less than five years. This brings a saving of as much as a quarter million units every day for an estimated 100,000 households.
At the individual household level the saving per month can be as much as 30 per cent of the energy bill because of the non-use of geysers and the installation of solar heating systems. This saving differential is narrowing down with the introduction of smarter geysers that have dropped the demand for electricity.
(d) The government will also do well if it ensures that every apartment block is mandated to install a tertiary sewage treatment plant in a manner that the treated water is ‘up-cycled’ for use in the flush tanks of every home. This will ensure that the demand for fresh water from such apartment blocks will reduce by as much as 40 per cent. This will also enable residents with greater water security over a longer term with the treatment system ensuring that residents ‘grow their own water in a loop’ and supplement fresh water for only the residual requirement.
(e) Any city will also benefit from legislation that will mandate every household and office to have a rainwater harvesting system installed both retrospectively for existing homes and prospectively for new buildings that are to come up.
For every 100 sq. m. of a building roof, the annual harvest that is possible of water is as much as 300,000 liters at annual rainfall that, say, a Mumbai receives of over 2000 mm.
Between the combination of rainwater harvesting, water-saving aerators for taps and showers, and the tertiary treatment plants for offices and apartment blocks, the fresh water demand will go down by a staggering 65 to 70 per cent.
Cities are already beginning to suffer the pangs of water shortages despite bountiful monsoons. This can be mitigated swiftly if the government brings in these enactments and ensures compliance. It is easy to berate the government for what it doesn’t do; a little bit of soul-searching from all of us — as citizens, producers and consumers — can make all the difference.
[f] One other interesting legislation that forward-looking cities should consider taking up in earnest is rooftop harvesting of fruits and vegetables in households and in office blocks.
As recently as the beginning of January 2011, Toronto has legislated the mandated harvesting of such crops on every rooftop, of commercial or residential spaces, which are over 2,000 sq. mt. or 20,000 sq. ft. Such directions are needed for our cities to combat a future that threatens serious shortage of natural resources. The crunch on the transportation energy front over the next 20 years will also compel many cities to adopt such practices. Countries like Sri Lanka are entirely dependent on the outside world for import of oil or gas or coal.
Way back in 1990 Havana was forced into making such a decision to mandate harvesting within cities on rooftops as well as in parks and open spaces in order to beat the challenge of the severe oil crisis that descended upon Cuba after Perestroika and Glasnost cut off their lifeline on Soviet oil tankers.
Philadelphia has introduced just at the start of January 2011 an ambitious program for creating ‘green infrastructure’ that will sensitize the creation of such amenities for the city to take on the challenges of the far longer term.
There is a lesson to be learnt from these trends of the future that are already before us. Cities, for example, like Colombo, have the advantage of being still manageable with about 600 sq. km. as geographic spread and a population no more than about one million as of now.
The other advantage that Colombo has is that its population growth is nearly neutral with no dramatic rise in the population growth that is expected into the decade before us.
With such supply-side thinking as these measures suggest, cities like Colombo, or Mysore, or Dehradun, or Indore can easily stand to be forerunners in such sustainable practices for urban management.
Some countries like Sri Lanka or the Phillipines already have taken the lead in green buildings.
