Sustainability of green energy

The primary goal of developing green sources of energy is to generate power while minimising waste and pollution, thereby reduce the negative impact of energy production on the environment. Agro-Energy is produced efficiently and in a sustainable manner by making significant contributions to achieving social and environmental sustainability at local, national, regional and global levels.
Sustainable energy implies development of energy production in a way so that it meets the needs of the present without compromising the needs of future generations. It is here that green energy is considered most pertinent. Traditional energy sources-- such as fossil fuels produce greenhouse gases that are believed to be the primary cause of global warming or climate change. Green energy can replace fossil fuels in all major areas of use including electricity, water and space heating and fuel for motor vehicles.
Agro-energy refers to the energy function of agriculture. It can have significant contributions to achieving social and environmental sustainability at local, national, regional and global levels. In fact, agricultural and livestock resources are abundant in most parts of the world, and various commercially available conversion technologies can transform current traditional and low-tech uses of these resources into modern energies. If agro-energy is produced efficiently and in a sustainable manner, benefits compared to fossil fuels can be achieved in food security, rural development, local self-reliance, better agricultural management, biodiversity conservation and climate change mitigation, whilst offering improved energy supply and security. Agro- energies can play a strategic role in shifting the balance of energy sources towards more environmentally sustainable combinations, and in the process provide farmers with stable revenues, at times of unpredictable commodity prices.
The UN Food and Agricultural Organisation (FAO) is trying to develop agro-energy for food security, rural development and climate change mitigation through the following objectives: (i) stimulating the integration of agro energy issues into the agricultural sector; (ii) promoting the potential of agro energy in the energy market; (iii) promoting sustainable management of energy resources, of energy conversion systems and of end-uses; (iv) enhancing food security and rural development through the implementation of agro energy systems; (v) contributing to climate change mitigation through implementation of agro energy systems.
Green energy comes from natural sources such as sunlight, wind, rain, tides, plants, algae and geothermal heat. These energy resources are renewable, meaning they are naturally replenished. In contrast, fossil fuels are a finite resource that take millions of years to develop and will continue to diminish with use. Green Energy is energy that can be extracted, generated, and/or consumed without any significant negative impact to the environment. The planet has a natural capability to recover, which means it can contain pollution to a reasonable limit by its own capability.
Renewable energy technologies are essential contributors to sustainable energy as they generally contribute to world energy security, reducing dependence on fossil fuel resources and providing opportunities for mitigating greenhouse gases (International Energy Agency, 2007).
First-generation technologies emerged from the industrial revolution at the end of the 19th century that included hydropower, biomass combustion and geothermal power and heat. Some of these technologies are still in widespread use. Second-generation technologies include solar heating and cooling, wind power, modern forms of bio-energy and solar photovoltaic. Third-generation technologies are still under development and include advanced biomass gasification, bio-refinery technologies, concentrating solar thermal power, hot dry rock geothermal energy and ocean energy. Advances in nanotechnology may also play a major role.
Green energy utilises energy sources that are readily available all over the world, including in rural and remote areas without access to electricity. Advances in renewable energy technologies have lowered the cost of solar panels, wind turbines and other sources of green energy, placing the ability to produce electricity in the hands of the people rather than those of oil, gas, coal and utility companies. The primary goal of developing green sources of energy is to generate power while minimising both waste and pollution. Scientists who advocate the use of green energy say that using such sources will reduce the rate at which climate change occurs, although it cannot stop or reverse the temperature increase.
Renewable energy, after its generation, needs to be stored in a medium for use with autonomous devices. Also, to provide household electricity in remote areas (that is areas which are not connected to the main electricity grid), energy storage is required. Energy generation and consumption systems are usually stand-alone power systems. Some examples are: (a) Energy carriers as hydrogen, liquid nitrogen, compressed air, oxy-hydrogen, batteries, power vehicles. (b) Flywheel energy storage, pumped-storage hydroelectricity is more usable in stationary applications (e.g., to power homes and offices). In household power systems, conversion of energy can also be done to reduce bad smell. For example, organic matter such as cow dung and spoilable organic matter can be converted into bio-char. To eliminate emissions, carbon capture and storage is then used.
Green energy is a commendable effort towards solving the world's increasing energy consumption; but it must be accompanied by a change in mindset to encourage its use. Besides the greening of fossil fuel and nuclear power plants, another option is the distribution and immediate use of power from solely renewable sources. As fossil fuel and nuclear power are still the main sources of energy in the main electricity net, replacing them will not be possible overnight. We need to ensure that everyone has access to energy, but in doing so, we cannot destroy the natural resources. If we are to achieve the goal of ensuring access to energy for everyone primarily through the use of fossil fuels, the negative effects of climate change would adversely affect crops, as well as farming and woodland. We need to promote renewable energy, not only for the privileged elite but also for the benefit of everyone.
The writer is a Lecturer at the Dept. of Sociology, Bangabandhu Sheikh Mujibur Rahaman Science and Technology University.
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