- The world moves rapidly towards greater urbanisation over the next few decades. And the backbone of any urban ecosystem is energy.The key question then is, how do we go about building energy-efficient cities? Here’s a possible path.
As our economic activities have come to be concentrated in our cities, so has our energy consumption. According to a World Urbanisation Prospects study by the United Nations, even though cities constitute only 2 per cent of land surface, they are home to over 54 per cent of the population. The report also projects that by 2050, two-thirds of the population will be living in cities and India, Nigeria and China will register the highest population growth rates.
The backbone of any urban ecosystem is energy; it is essential for all commercial and residential purposes, as well as for services such as transport and communication.
Several factors control the energy demand for a city. The rate of expansion and type of functions that a city performs play a significant role. Energy use would differ according to the spatial design of the city, type and location of economic centres, the transport system (especially availability of public transport), climate and lifestyle.
A relation between energy consumption and gross domestic product (GDP) growth can also be seen. Gaining access to energy sources boosts GDP growth and higher GDP in turn drives energy demand. This forms a vicious cycle. In 2013, urban areas accounted for 64 per cent of total energy demand. As the world economy is expected to double over the next 20 years, the demand will only increase further. However, with improving sensitivity about our planet’s limited fossil reserves and the alarming rate of increase of global greenhouse gases, there is a shift away from the power-intensive growth model and towards a more sustainable one. This article looks at some particular instances of sustainable energy practice in cities. Before charting out solutions, however, let us look at some major issues with energy in cities.
Most cities, while trying to meet their energy requirements, face the challenge of providing energy for all. In addition, developing nations also face high supply costs on petroleum products due to inadequacies in the supply chain. This limits the ability of such governments to provide basic goods and services to people (especially the poor). Subsides are often used as a political tool, but they affect the financial health of generators and distributors. The only sustainable way forward is a shift away from fossil fuels and towards cleaner ones.
Cities around the world are struggling to provide clean, affordable and reliable energy to all. According to a World Bank study, 132 million people in urban areas lack access to energy and 482 million people lack clean fuel, the latter contributing to indoor air pollution. Setting up infrastructure to meet this demand can often be time-consuming and capital-intensive.
3. Air quality
Combustion of fossil fuels releases a number of harmful gases such as carbon dioxide, mono oxides of sulphur and nitrogen, and particulate matter, impacting human health and environment adversely. Our policy makers therefore also have to focus on increasing energy efficiency by scaling up renewable resources, adopting pollution control measures and innovations in capture and storage of carbon.
Now, here’s a road map for building energy-efficient, sustainable cities:
1. Lowering consumption
Every unit of power saved is equal to two units of power generated. Thus, one important step towards sustainability can be reducing the total power consumption on the part of end users. This can be done either by developing appliances that use less power or by cutting down on activities (such as driving) that are energy-intensive.
2. Energy-efficient transport
Cities need to focus on people and not vehicles, and so there is a need to develop efficient transport systems. To move away from fossil fuels, city planners and policy makers need to move towards non-motorised modes of transport such as walking and cycling as well as mass transits, to optimise fuel use.
For example, with its dedicated cycle lane, Rotterdam now has more cycles than people. Barcelona too has developed a system of bicycle sharing with over 400 stations spread across the city, especially near public transport stations, to provide efficient last-mile connectivity.
3. Energy-efficient buildings
Large buildings are the largest consumers of energy, but they are also the biggest opportunities for saving energy. Since a large portion of the energy is consumed in heating and cooling of buildings, building design can be altered to tackle this problem. Buildings should provide adequate day lighting, ventilation and passive heating and cooling, green roofs, solar thermal water heating and energy-efficient appliances and lighting.
An example of an energy-efficient building can be found in New Delhi at Indira Paryavaran Bhawan, the office building of the Ministry of Environment and Forests. It is a “net zero” building which consumes 70 per cent less energy than a conventional building, and has its own solar plant, water recycling facility and geothermal heat exchange system.
4. Urban planning
As cities expand horizontally, their energy consumption also increases. More energy becomes necessary for transport as well as new infrastructure and services. Compact and dense cities, on the other hand, require less energy. Planned distribution of residential and commercial services along with mixed land use and mass transit corridors reduce dependency on private vehicles and, consequently, energy consumption.
5. Improving renewable energy
While the renewable energy market is expanding, it can receive further impetus from government policy initiatives, cost reduction and better energy output. One of the major shortcomings of energy sources like solar and wind is that they don’t offer continuous supply, and they need to be supplemented with traditional sources such as coal to overcome intermittency. Renewables offer opportunities for decentralised power generation and can generate income at the local level.
6. Designing circular energy systems
A circular energy system transforms unutilised energy into a source of energy for other functions. The system can manifest itself as “co-generation” – simultaneous production of two types of energy from the same source. Such a circular system can help conserve energy especially in large establishments such as malls or factories. For example, Rotterdam connects higher temperature effluents from industries and its waste to the city’s central heating system to be used for heating purposes for residential areas.
7. Efficient transmission
India loses around 20 per cent of its total power generated to inefficiencies of the grid. Introduction of smart grids along with smart metres and appliances can help minimise such losses and optimise power delivery.
There is a need for an integrated and comprehensive approach to conserve and optimise energy in urban areas. As energy use is scattered and multi-sectoral, so has to be the policy concerning it. So an ideal energy policy for a city would involve planning for transport, infrastructure and design of buildings. This has to be further augmented through a sustainable shift towards renewables and sensitisation of consumers to conserve energy.