Waste to energy facilities

Overview

One of the outcomes of Alberta’s Energy Strategy is to promote the development of renewable energy. This includes wind, solar and biomass energy. Turning waste into energy is becoming more popular since it can significantly reduce the amount of waste to landfills and could reduce carbon emissions by displacing fossil fuel consumption.

Alberta's Environmental Protection and Enhancement Act (EPEA) and accompanying regulations detail which waste to energy activities require approvals and how they are secured.

Information required in an application includes:

• an account of any public consultation undertaken or proposed by the applicant
• the location, capacity and size of the activity
• the nature of the activity

For more information on the regulatory process for waste to energy facilities, please see detailed information on the approval process at Apply for Environmental Protection and Enhancement Act approvals.

Energy recovery from wastes can be done by using technologies such as anaerobic digestion, gasification, combustion or incineration with energy recovery. Technology selection is based on the quality and quantity of the wastes.

Anaerobic digestion

Anaerobic digestion is the decomposition of organic matter which occurs in absence of oxygen. Anaerobic decomposition of organics generates biogas composed primarily of methane (CH₄) and carbon dioxide (CO₂). The methane gas produced from these digesters can be used as fuel to produce heat and electricity.

In Alberta, anaerobic digestion facilities (digesters) typically use livestock wastes such as manure as the main feedstock for biogas (60 - 70% methane) production. Depending on the type of digesters used, the manure can be in liquid or semi-solid form.

Input of feedstock from different sources can enhance methane gas production. A large variety of organic wastes and by-products can be used as feedstock for anaerobic digestion. The residues from the digesters (digestate) can be used as a soil amendment and fertilizer.

Gasification

Gasification is the process of converting waste into a gaseous product (called syngas) by exposure to high temperatures in the presence of oxygen or steam.

Syngas is primarily composed of carbon dioxide, hydrogen and carbon monoxide and can be burned as fuel or further refined to a liquid fuel.

This technology has been used in the past successfully for homogenous material streams such as wood and coal.

Several municipalities in Alberta are exploring this technology for converting municipal solid waste streams into fuel and power. A diagram illustrating the general process if provided in the figure on the right.

Incineration

Incineration is the process of thermal destruction (in the presence of oxygen) of either a selected waste or mixed waste feedstock. The heat recovered from incineration can be used to generate electricity or provide district heating.

District heating is the production and distribution of thermal energy, produced by a central plant which is then distributed to the community through a piping network. This can be used to heat warehouses, commercial businesses or homes.

The incineration of waste and utilizing the energy from these systems to produce heat and electricity promotes sustainability by displacing fossil fuel consumption.