Regardless of the source, energy is a major factor for development. It is needed for transport, industrial and commercial activities, buildings and infrastructure, water distribution, and food production. Most of these activities take place in or around cities, which are on average responsible for more than 75 per cent of a country’s Gross Domestic Product (GDP) and therefore the main engines of global economic growth.
To run their activities, cities require an uninterrupted supply of energy. They consume about 75 per cent of global primary energy and emit between 50 and 60 per cent of the world’s total greenhouse gases. This figure rises to approximately 80 per cent when the indirect emissions generated by urban inhabitants are included.
Buildings also consume vast amounts of energy at all stages of their existence. Energy is needed for the raw materials, construction process, and maintenance and daily operational needs such as lighting, air conditioning, and cleaning. In addition, urban sprawl, increasing distances between destinations, and inefficient public transport systems prompt overall reliance on private motorized transport, such as cars, which have a high energy consumption, mostly of petroleum products.
In 2012, global energy supply consisted of 81.3% fossil fuels (oil, coal and gas), 9.7% nuclear power, and only 9% renewable energy sources (such as hydro, wind, biomass and solar). Unfortunately, this widespread use of fossil fuels causes a number of challenges. Carbon-based energy generation has a large ecological footprint, not only due to rising greenhouse gas emissions and pollution caused by burning fuels, but also because of extraction techniques that contaminate the environment, and frequent production or delivery accidents.
Furthermore, because of the current mono-dependency on fossil fuels, supply drops or price hikes can easily disrupt economies. Fossil fuels are also all too often a source of regional conflicts and are misused as a means of political pressure. Besides, fossil fuel resources are not infinite, and their depletion is a near reality.