This April 1 started the management period of critical episodes that could prohibit the use of firewood on days of environmental emergency. UDT carried out a study that proposes an alternative to conventional heating and seeks to identify sources of residual heat from industrial processes to feed local heating systems and domestic hot water, the so-called district heating.

From April 1 to September 30, the Management of Critical Episodes (GEC in Spanish) will take effect, which will implement different restrictions according to the air quality forecast that will be issued by the SEREMI of the Environment of the Biobío Region. Among the measures with the greatest impact on the population is the ban on the use of firewood on days of very poor atmospheric quality.

This is one of the instruments contemplated in the Environmental Decontamination Plan (PDA in Spanish) for the Gran Concepción, which came into effect in December 2019 and aims to reduce the concentration of particulate matter by 40% within a period of 10 years. This will benefit more than 1 million people living in the communes of Talcahuano, Hualpén, Penco, Tomé, San Pedro de la Paz, Coronel, Lota, Chiguayante, Hualqui and Concepción.

Other measures designed in this program are the reduction of emissions from industrial boilers and furnaces; the reduction of household emissions, implementing the replacement of 20 thousand heaters; the delivery of 20 thousand subsidies for thermal insulation, and the improvement of the quality of the firewood used for heating. The plan has a total cost of more than 230 million dollars.

Gran Concepción, area saturated by particulate matter

“In 2015, the Metropolitan area of Concepción was declared a Saturated Area by breathable fine particulate matter and, that same year, the process of preparing the Environmental Decontamination Plan began. Part of this work was to carry out studies to find solutions that allow the reduction of emissions of particulate matter from fixed sources. This is how the Ministry of the Environment and CIFES tendered the research “Study for the identification of residual heat for district heating projects located in the metropolitan area of Concepción” that was developed by the Bioenergy Department of the Technological Development Unit, UDT, of UdeC”, points out Dr. Cristina Segura, head of the Bioenergy Department of UDT.

The objective of this research was to estimate the excess heat from industrial processes within Metropolitan Concepción as to evaluate its use in district heating projects for the area.

Industrial residual heat for district heating

District heating considers the distribution of thermal energy from a central source of heat generation to a large number of residential homes, by transporting steam or hot water through a network of insulated pipes. Thermal energy can come from various sources: thermal power plants with fossil or renewable fuels, geothermal energy, cogeneration of heat and excess heat or residual heat, which are produced daily by industrial plants in the area, as one of the most interesting alternatives.

District heating systems supply a large part of the heating requirements in cities of countries such as the United Kingdom, China, France, New Zealand, the United States, Canada, Germany, among others. In Chile, it is worth highlighting the district heating system of the Universidad de Concepción and a few minor projects in buildings and condominiums in the Metropolitan Region and Temuco.

“In total, the UDT study identified 31 industrial plants in the Metropolitan Concepción, of which 19 were selected to estimate the usable residual heat. The vast majority of these plants are located near residential areas with high consumption of firewood for heating. The results revealed a potential of 62 MW of recoverable residual heat for heating projects. The communes with the highest potential for industrial residual heat are Coronel, Hualpén, Penco, Talcahuano and San Pedro de la Paz”, explains Dr. Segura.

A pre-feasibility and emission reduction study was also carried out, analyzing 5 alternative projects to establish a district heating network. The one that presented the best conditions was the one located in San Pedro de la Paz, due to the proximity of the power generating plant to the urban area, ease of network layout, quality of the homes and high population density, among others. The approximate initial investment is estimated at 1.5 million dollars. The proposal could be entered into the bank of emission compensation projects of the Ministry of the Environment.

In summary, the residual heat that industries emit in their production processes and that is released into the environment without using it, can be recovered through systems developed and tested in different parts of the world to feed district heating networks. In the case of Chile, this energy could partially replace fossil fuels and firewood, which are fixed sources of environmental pollution every winter.