Over the past twenty years, urban areas have experienced remarkable growth. Currently, more than 3.5 billion people live in urban areas (almost half of the world’s population). It is developing countries in particular that are subject to a rapid shift from rural to urban economies as they transform through their urban populations (UN-Habitat, ICLEI and UNDP, 2009, p. 7) . Although the extent of urbanization in developing countries varies in size and pace, its challenges include meeting a growing demand for secure energy supplies, building bridges of access, achieving equity and to empowerment, to reduce environmental degradation, to improve human health and livelihoods, and to chart new directions. in development (Droege 2008K p.1).
The world’s population has doubled since 1960, and is expected to exceed nine billion by 2050. Developing countries are expected to experience 99 percent of this population growth, in addition to 50 percent of urban growth. (Chu and MajumdarK 2012: Curry and pillay, 2012). According to the United Nations Environment Program, Latin America and the Caribbean are characterized by a high degree of urbanization, with 78 percent of the population living in cities in 2007. By 2050, this proportion is expected to increase to 89 percent. While Africa and Asia are less urbanized, with nearly 40 percent of the population currently living in cities, both regions have also experienced high rates of growth. Their urban population is expected to increase to 62 per cent by 2050 (as reported in UN-Habitat, ICLEI, and UNEP, 2009, p. 7). The United Nations predicts that by 2050 there will be 6 billion people living in cities.
The global energy crisis, coupled with the threat of climate change, requires that innovation in the energy sectors and responsible consumption be taken into account for both developed and developing countries. In the Urban Energy Transition: From Fossil Fuels to Renewable Energy, it was stated that by 2030, global energy requirements are expected to increase by 60 to 85 percent. According to the recommendations of the Intergovernmental Panel on Climate Change, if we limit global warming to no more than two degrees Celsius above pre-industrial levels, we cannot exceed a level of greenhouse gas concentrations in the atmosphere of 450 parts per million. But in March 2015 the National Aeronautics and Space Administration (NASA) revealed that the 400 parts per million level had been exceeded. In order to ensure an available, feasible, healthy and environmentally sound future, the world needs a new industrial revolution in which development is provided with energy resources that are affordable, available and sustainable. In an attempt to reduce resource inputs and environmental impacts, some developed countries have already successfully separated economic growth from the reality of energy consumption. This goal was achieved by closing the energy gap in production, for example by reabsorption of heat released from electricity generation (UN-Habitat, ICLEI, and UNEP, 2009, p. 7). Hence, energy efficiency and energy conservation, as well as decarbonization processes in energy sources, have become essential to this revolution.
Although fossil-fuel-based power generation continues to play a major role in cities, it is increasingly clear that sustainable energy is the only option moving forward. For example, in cities, the share of fossil fuels may remain large even though they often use cogeneration and local heating that are characterized by high fuel efficiency. The implementation of strategies related to renewable energy in N environments is in turn rapidly becoming one of the “energy imperatives”. Activating the transformation requires not only transforming the energy source but also ensuring that it is cost-effective, sustainable and beneficial for development. Cities around the world are now pledging to use 100 percent clean energy, with Copenhagen pledging to become carbon neutral by 2025. Aspen, Colorado, is expected to use 100 percent renewable energy by 2015, while Munich plans To make 100% of its electricity generated by renewable energy by 2025.
The generation and management of energy from urban waste has been a fundamental issue due to the expansion of urbanization and the increase in population. As for anaerobic digestion, where bio-waste is decomposed in the absence of oxygen, which leads to the production of a methane-rich biogas suitable for energy production, it can provide a fundamental solution to the growing waste issues, while at the same time reducing external energy requirements (Curry and Pillay, 2012). ). Biogas can be flared to produce either heat or electricity using internal combustion machines or micro-turbines and hot water heaters where the heat generated is used to heat digesters or heat buildings (ibid.). If urban waste can be used to produce biogas, and then reduce the demand for landfills, sustainable and renewable energy can be produced along with a useful by-product of gas derivatives that can be used as fertilizer. A study published by Currie and Pillay in the Journal of Renewable Energy found that the number of biogas plants is increasing each year by approximately 20 to 30 percent, proving that anaerobic digestion is still an important and sustainable source of energy (2012).
The primary benefit of using solar energy as an energy resource, as compared to biomass and hydroelectric or nuclear, is that it does not require water, thus eliminating environmental concerns regarding increased water consumption, which leads to water shortages. Also, the recent cost reductions in the implementation of solar technologies (concentrated or solar photovoltaic) have made them cost-competitive with fossil-fuel-based power generation, both in the mid to high range. At the global level, photovoltaic energy grew to represent the fastest of all renewable technologies between 2006 and 2011, increasing by 58 percent annually, followed by concentrated solar energy, which in turn increased by about 37 percent, and then wind energy, which grew by 26 percent, as shown in the study on energy policy (Purohiot, Purohit and Shekhar, 2013). Solar energy for urban use is considered energy efficient in view of the possibility of placing photovoltaic panels and materials on rooftops where they do not obstruct anything while being efficient and low maintenance. Global CSP capacity is estimated to reach 147 GW in 2020, 337 GW in 2013, and reach 1,089 GW in 2050 (ibid.).
In the future, the development of on-site renewable energy production could lead to zero-emission buildings and eco-cities with a high level of energy efficiency and low carbon (Lund, 2012). That’s because innovative new technologies are advancing every day and making cities more sustainable in terms of energy. For example, a harvester of wind, solar and rainwater is being developed for use in high-rise urban buildings in order to reach the optimum level of energy production, and it helps to reduce the difficulties encountered in the current urban uses of wind turbines.
Echo – cities
With the advancement of technology, there is an increase in the number of eco-cities around the world. Examples of such “sustainable urban areas” are Masdar City in Abu Dhabi and the Valley of Smart Cities (PlanIT) in Portugal. The Tianjin Eco-City is set to become the largest of its kind in this regard, a cooperative project between China and Singapore that, by 2020, will provide the homes of more than 350,000 residents with a livelihood in a green, low-carbon environment that is about half the size of a suburb. Manhattan. These cities include infrastructure with water-saving devices, insulated walls, double-glazed windows to absorb sound, south oriented for increased passive heat, roofs and walls that contain solar photovoltaic energy, as well as on-site power plants.
However, the implementation of renewable energies in urban environments sometimes encounters obstacles due to the mismatch between supply and demand, as well as their integration into the energy system. Smart grids can provide the connections and controls necessary for the effective management of energy savings. Implementation of these measures in the urban environment results in many benefits including improved energy security and reliability, reduced distribution costs by bringing the local energy supply group closer to the level of demand, while using already existing infrastructure, and working to reduce the demand for Land to a minimum (ibid.).
About the author : Laura Phillips and Pete Smith
Laura Phillips is a PhD candidate in Biological Sciences at the University of Aberdeen, Scotland, UK. Her thesis is “What are the environmental consequences of achieving food security?” Pete Smith is Professor of Plant and Soil Sciences at the Institute of Biological and Environmental Sciences, School of Biological Sciences, University of Aberdeen, Scotland, UK. Mr. Smith is the lead author and coordinator of the chapter on “Agriculture, Forestry and Other Land Use” in Climate Change 2014: Mitigating Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. It was published by Cambridge University Press.
UN chronicle article 20324.