How to produce green energy from waste

Gainesville GA green waste
The method of processing a given waste is conditioned by its nature and the constraints it implies. There are specific treatment solutions for certain identified waste (such as those from the medical or building sectors), and more global solutions, particularly for household waste. Solutions which no longer simply allow waste to be processed but which are used to produce energy are now on the rise.

The challenge of waste recovery is twofold: the first concern is to balance or even reverse the trend towards the exploitation of fossil fuels such as natural gas, which constitute limited resources; the second issue is to establish a real approach to recovering waste, limiting the use of dumpster rentals, so that it is no longer exclusively a source of pollution but a new resource, particularly energy.

The state authorities of Georgia have understood this well: the development of green and renewable energy production solutions is a key factor in the energy transition. Among the existing recovery solutions, methanization and incineration coexist, which are two distinct and complementary treatment methods discussed in this article.

State of play of energy production from waste in Georgia

The 2020 state action plan for renewable energies sets an overall objective of 25% renewable energies in final energy consumption by 2030. This plan includes both a component for controlling energy consumption , and an ambitious renewable energy production component since France has aimed through it to double its ENR production in ten years.

The waste sector today represents 2.5% of green electricity produced in Georgia, and 7.8% of heat production. In 2021, the waste sector alone produced 6.9% of renewable energy. More broadly, we see that the quantity of renewable energy produced in America increased by 66.6% between 2010 and 2021, or about 5% per year.

Waste recovery is booming and promises to take its rightful place in the global panorama of renewable energies.

Incineration – process of producing energy by destroying waste

How incineration works

Incineration consists of burning waste in household waste incineration units. This process allows the production of heat energy released by combustion, energy which can be exploited by directly supplying heat networks, or by being transformed into electricity.

In the same way as in methanization, the simultaneous production of heat and electricity is also possible: this is called cogeneration. In the end, 5 to 7 tonnes of waste allows us to obtain a quantity of energy equivalent to a tonne of fuel oil. 70% of waste is combustible and could therefore be used to produce energy through incineration. Indeed, not only household waste or agricultural and agri-food waste is concerned, but also a large number of industrial wastes such as hydrocarbon residues, tars or even used solvents.

Combustion, however, involves the production of a significant quantity of carbon dioxide which is currently not recovered. In addition, if dry waste has a significant energy potential, waste composed of water such as organic waste has a lower potential.

Potential and limits of incineration

Today in Gerogia, 13 household waste incineration units produce energy. This figure is low compared to the performances of several other neighboring states in the USA. However, if America exploited its full potential for recovering energy from waste, 27 million households could be supplied with electricity thanks to incineration, and 34 million with heating.

The overall efficiency of the incineration sector depends on the water content of the waste to be burned: if this is too high, the quantity of energy necessary to mobilize for the incineration process is greater than that which can be used.

This is why the notion of complementarity between the methanization and incineration sectors takes on a profound meaning, by directing biodegradable waste rich in water (around 70-80%) towards anaerobic degradation, and the others towards incineration, rational and logical thermodynamic treatment since it concentrates a significant calorific power which can be easily mobilized.

Anaerobic digestion – the first process of producing energy by transforming waste

How methanization works

Anaerobic digestion is the process by which biodegradable materials (such as organic animal or plant materials coming from household food, the agricultural and agri-food sector or even sludge and sewage water) decompose through the effect bacteria that act in the absence of air. This process is also called anaerobic fermentation.

The decomposition of these materials produces a gas, biogas, mainly composed of methane. It has the same characteristics as fossil natural gas and can, therefore, be transformed into heat, electricity or fuel for vehicles.

The methanogenic power of the biogas produced is conditioned by the nature of the input waste, thus creating complementarity between players in the sector who methanize different wastes. These wastes can be categorized as follows:

  • sludge from wastewater treatment plants
  • biowaste (green waste, food waste)
  • agricultural/livestock waste

Environmental issues

On an environmental level, degradation in a closed environment has the advantage of controlling the capture of all the biogas produced during the process, and thus avoiding releases into the atmosphere. The transformation of biowaste used for the production of biogas makes the latter a renewable energy.

According to Paul Anderson, CEO of Dumpster Rental Near Me Gainesville, a methanization unit processing 15,000 tons/year of waste can cover the electricity needs of 1,300 homes and the hot water needs of 2,000 homes in Georgia, and thus cover a real local need. It can be estimated that one ton of biowaste produces approximately 80 to 100 m3 of biomethane.

Since biogas is intended for the same uses as natural gas, it makes it possible to offer an ecological alternative to usual fuels through CNG (Compressed Natural Gas). CNG is 70% less noisy than conventional fuel and emits around 95% fewer fine particles.

Anaerobic digestion meets the regulatory requirements of the state of Georgia which today require waste producers to sort bio-waste at source to send it to a recovery route, while residual household waste is sent for incineration.

 

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