By Dr Moses Amweelo
WHEN most people think of renewable energy they think of wind energy, hydropower, solar energy, biomass, biofuel, geothermal energy and so on. However, there is another source of energy that is created everyday across the globe.
Energy from waste offer a safer and technologically advanced means of waste disposal, while also generating clean renewable energy, which could reduce greenhouse gas emissions into the atmosphere and supporti recycling through the recovery of metals.
Although energy is central to the provision of goods and services and to production in mining and industry, transportation to enhance comfort and livability in the domestic context, the generation and use of energy has some negative consequences for the environment.
The extent and magnitude of such environmental impacts are determined by the sources of energy and can limit sustainable growth if kept unchecked. As in many other developing nations, energy use in Namibia is increasing at a rate that may be unsustainable in the long-term.
To counteract this trend, our government has initiated programmes and policies such as our national development plans, the Environmental Management Act, the Cabinet directive on compulsory use of solar waste heaters by public institutions and the national policy on climate change for Namibia in order to encourage efficiency measures to reduce energy consumption and to reduce adverse environmental impacts.
The enormous increase in the quantum and diversity of waste materials generated by human activity and their potentially harmful effects on the general environment and public health, have led to an increasing awareness about the urgent need to adopt scientific methods for the safe disposal of waste. While there is an obvious need to minimize the generation of waste and to reuse and recycle them, the technologies for recovery of energy from wastes can play a vital role in mitigating the problems.
Besides recovery of substantial energy, these technologies can lead to a substantial reduction in overall waste quantities requiring final disposal, which can be better managed for safe disposal in a controlled manner while meeting pollution control standards.
Municipal solid waste refers to the stream of garbage collected through community sanitation services. Such waste can consist of a variety of materials, including both renewable energy sources (such as food, paper, and wood) and non-renewable energy sources (such as glass, plastics, and tires). Obviously, as several sources have shown, from an environmental perspective the most sustainable option for municipal solid waste is to reduce the amount of waste.
“The goal of waste management, in any country, should be to reduce the amount of garbage generated, while reusing as much of what remains,” according to Schönning (2006). Municipal solid waste combustion reduces the need for new landfills; only the ashes generated in the incineration process are disposed off at landfill sites but these are much smaller in volume and thus require less space. Such ashes may be toxic, however, which requires regular testing to prevent toxic substances from migrating into groundwater supplies. In the EU, waste incineration is preferred over landfilling and the landfilling of biodegradable waste is limited by law.
Combustion of municipal solid waste could contribute to reducing greenhouse gas (GHG) emissions when the heat and electricity produced replace fossil fuel-based capacity. Depending on the prevailing mix of primary fuels used for electricity generation or heat production and the composition of collected waste (which may very much differ from country to country, or from region to region).
The growing use of waste-to-energy as a method to dispose off solid and liquid waste and to generate power has greatly reduced environmental impacts of municipal solid waste, including emissions of greenhouse gases. Waste-to-energy conversion reduces greenhouse gas emissions in two ways. Electricity is generated which reduces the dependence on electrical production from power plants based on fossil fuels.
The greenhouse gas emissions are significantly reduced by preventing methane emissions from landfills.
Dr Moses Amweelo is a SWAPO Party parliamentarian and a former Minister of Works and Transport.