The goal of this study was to compare the environmental impact of the current residential heating systems in Central and Southern cities in Chile, with alternative energy sources such as electricity, as well as the impact of a higher contribution of solar energy in the Central Interconnected System (SIC). A Life Cycle Analysis (LCA) was conducted in order to compare its environmental impact.
The study is divided into 4 parts: Chapter 1 describes the goal and scope of the LCA, Chapters 2 and 3 provides information of the current electricity matrix in the locations where the study is developed, as well as the most common heating technologies. Chapters 4 and 5 describes the proposed scenarios and environmental impact results.
Projections of economic growth in Chile in the following years involve higher energy demand and therefore, the need of an efficient energy supply in order to ensure both sustainable and economic growth. In that context, consumption of firewood represents an important role, considering the high availability of this energy source in Chile. In the entire country, the capacity of energy generation from biomass is estimated to be from 310 MW to 470 MW.
The main use of firewood is for residential heating, however, firewood is associated not only with environmental issues, but also with public health problems. Fine particulate matter (PM 2.5) is an air pollutant that are two and one half microns or less in width, that is an issue when reaches high levels. These particles are able to travel deeply into the respiratory tract, reaching the lungs, exposure to fine particles can produce asthma and hearth disease. Long term exposure to fine particulate matter could be related with increased rates of chronic bronchitis, reduced lung function and increased mortality from lung cancer and heart disease. Other alternatives commonly used are liquefied natural gas (LNG), electric heaters, refined oil, etc. Data from the Ministry of the Environment (MMA) shows the low air quality of various cities in the Center and South of Chile.
Table of Contents
List of Figures
List of Tables
Introduction
1. Goal and Scope
2. Energy Matrix of Chile
2.1 SIC Grid
2.2 Transmission losses
2.3 Energy required per functional unit
3. Heating systems in Chile
3.1 Air Pollution from wood burning
3.2 Types of heating systems and emissions
4. Scenarios and Inventory Analysis
4.1 Residential heating
4.2 Electricity
5. Environmental Impact Results
5.1 Greenhouse Gas Emissions
5.2 Particulate Matter
5.3 Sensitivity Analysis GWP
5.4 Sensitivity Analysis PM
6. Conclusions and Recommendations
7. References
EXECUTIVE SUMMARY
The goal of this study was to compare the environmental impact of the current residential heating systems in Central and Southern cities in Chile, with alternative energy sources such as electricity, as well as the impact of a higher contribution of solar energy in the Central Interconnected System (SIC). A Life Cycle Analysis (LCA) was conducted in order to compare its environmental impact.
The study is divided into 4 parts: Chapter 1 describes the goal and scope of the LCA, Chapters 2 and 3 provides information of the current electricity matrix in the locations where the study is developed, as well as the most common heating technologies. Chapters 4 and 5 describes the proposed scenarios and environmental impact results.
The results of this study prove that the main pollutant from these heating systems are fine particles, which represent a high risk to human health. However, if electricity replaces 30% of the current heating systems, the emissions of PM 2.5 would be reduced in 9.5%, moreover, if 30% of that electricity comes from solar energy, the reduction of fines particles would be 17.2%. In an optimistic scenario, when 80% of heating systems are based on electricity, the reduction of this pollutant would be 30%, in addition, if this electricity is 30% solar, the reduction of PM 2.5 would be 63.9%.
In addition, the use of firewood in all the scenarios proposed, contribute the most in the GHG emissions related with carbon dioxide biogenic and methane biogenic, nevertheless, the high dependency on fossil fuels for electricity production generates a high impact in the CO2-eq emissions from carbon dioxide and methane fossil, as well as nitrogen oxides.
To reduce the GWP in the scenarios where electricity is used for residential heating, the grid will have to become cleaner, reducing the amount of coal and petroleum as well as conventional hydro. Despite being renewable, conventional hydro presented a high number of GHG emissions, this could be attributable to the environmental impact of the downstream water that flows from the dam and inundates green fields that will decompose and generate GHG, mainly methane.
In an ideal scenario, where solar energy replaces 100% the electricity generation from coal, natural gas and petroleum diesel, and hydro run-of-river replaces 100% conventional hydro, the use of 30% of electricity with these characteristics would reduce in 27.8% the emissions of CO2-eq from carbon dioxide fossil compared with heating systems, and 76.6% from the current electricity matrix. In total, the reduction of CO2-eq under this ideal scenario would be 0.35 tons per MWh of heat produced, compared with heating systems and 0.4 tons MWh compared with the current electricity mix in Chile.
In conclusion, the replacement of heating systems for electricity would be a solution to reduce the emissions of PM, especially fine particles. However, this would have an impact in the GHG emissions that comes from fossil fuels in the electricity production, such as carbon dioxide fossil, nitrogen oxides and methane fossil.
It is suggested from the results of this project, to stimulate the use of electricity for residential heating but, first of all, improve the quality of the energy produced in Chile by introducing less contaminant technologies such as solar.
With a coast that extends for over 4,000 kilometers and it's home to the world's driest desert, the country has privileged conditions for the development of non-conventional energy. At this time, the energy sector is one of the most dynamic areas of the Chilean economy. It is expected that within the next few years, a cleaner energy matrix becomes a reality that can benefit the quality of life of all Chileans.
List of Figures
Figure 1. Average concentration of PM 2.5 (pg/m3) in 49 monitoring stations in Chile
Figure 2. Comparison of PM 2.5 emissions from different heating devices
Figure 3. Scenarios 1 and 2
Figure 4. Scenario 3
Figure 5. Installed Capacity and Energy Production SIC by technology
Figure 6. Thermal electricity by type of fuel
Figure 7. Map of SIC grid
Figure 8. Northern area of SIC grid
Figure 9. Electric power transmission and distribution losses in Chile
Figure 10. Contribution of each fuel in the energy supply for heating in 2013
Figure 11. Fuel mass required to produce a MWh of heat
Figure 12. Energy required in the production of 300 kWh from different technologies under Scenarios 2 and 3
Figure 13. GHG emissions under 3 different scenarios (g CO2-eq/ functional unit)
Figure 14. PM emissions under 3 different scenarios (g PM/ FU)
Figure 15. CO2-eq from carbon dioxide fossil in electricity for heating vs % Solar in SIC grid
Figure 16. CO2-eq from nitrogen oxides in electricity for heating vs % Solar in SIC grid
Figure 17. GWP emissions per functional unit
Figure 18. Comparison of 2.5pm <PM< 10pm emissions for Scenario 1 and electricity with different contributions of solar
Figure 19. Comparison of PM<2.5pm emissions for Scenario 1 and electricity with different contributions of solar
Figure 20. Comparison of PM> 10pm emissions for Scenario 1 and electricity with different contributions of solar
List of Tables
Table 1. Contribution to electricity production in Scenario 2 and 3
Table 2. Heating systems recommended by the MMA
Table 3. PM 2.5 emissions produced by different heating systems
Table 4. Heating System proposed by the Ministry of the Environment
Table 5. Energy required in the production of 1 MWh from different heating sources
Table 6. Mass of fuel required in the production of 1 FU from different heating sources
Table 7. GWP factors (AR5)
Table 8. GWP emission data heating systems (g/kg)
Table 9. CO2-eq emission data heating systems (g CO2-eq/kg of fuel)
Table 10. GWP emission data electricity production technologies (g/kWh)
Table 11. CO2-eq emission data electricity production SIC grid (g CO2-eq/kWh)
Table 12. PM emissions of different fuels (g/kg)
Table 13. PM emissions of different technologies for electricity production (g/kWh)
Acknowledgments
I would like to extend my gratitude to:
Prof. Vasilis Fthenakis, for sharing his expertise in the solar systems engineering field, and for welcoming me in the Center for Life Cycle Analysis research group.
My co-advisor Prof. Thanos Bourtsalas for his guidance, helpfulness and willingness to attend all my questions and concerns.
Prof. Jorge Jiménez and Pablo Catalan, from University of Concepcion, Chile, for believing and recommending me in the application process to the Engineering School at Columbia University.
Harry Donas PE, who has been both friend and family in New York, for his assistance with my professional development and my English skills.
Michael Hillmayer, who challenged me to apply to Columbia University and kindly introduced me to the student life afterwards.
Friends at Columbia and New York, who cheered me up during stressful times, and who have been the best multicultural family in the city, thank you for making this stage of my life much more fun.
My family, who has motivated and supported me all these years, for encouraging me to pursue my studies and for being always close despite the distance. All the achievements and everything I am is thanks to you.
Finally, I would like to thank the National Commission for Scientific and Technological Research of Chile, CONICYT, for funding my studies through the Becas Chile Scholarship.
Introduction
Projections of economic growth in Chile in the following years involve higher energy demand and therefore, the need of an efficient energy supply in order to ensure both sustainable and economic growth.
In that context, consumption of firewood represents an important role, considering the high availability of this energy source in Chile. In the entire country, the capacity of energy generation from biomass is estimated to be from 310 MW to 470 MW (Ministry of Energy, 2008).
The main use of firewood is for residential heating, however, firewood is associated not only with environmental issues, but also with public health problems. Fine particulate matter (PM 2.5) is an air pollutant that are two and one half microns or less in width, that is an issue when reaches high levels. These particles are able to travel deeply into the respiratory tract, reaching the lungs, exposure to fine particles can produce asthma and hearth disease. Long term exposure to fine particulate matter could be related with increased rates of chronic bronchitis, reduced lung function and increased mortality from lung cancer and heart disease (New York State Department of Health, 2011). Other alternatives commonly used are liquefied natural gas (LNG), electric heaters, refined oil, etc.
Data from the Ministry of the Environment (MMA) shows the low air quality of various cities in the Center and South of Chile (MMA, 2015). Figure 1 shows that, of the 49 stations monitoring contaminant PM 2.5 in the country, 29 are above the annual standard (20 ^g/m3).
Several studies suggest the replacement of inefficient heating devices currently used in these cities. It is estimated that a non-certified firewood system may release 6,600 times more PM than a heating system based on clean fuels such as electricity, natural gas or paraffin (EPA, 2016). The graphical comparison is shown in Figure 2.
The Interconnected Central System (SIC) grid supplies 92.2% of the Chilean population (Generadoras de Chile, 2016). Currently, the Chilean Energy Matrix is highly dependent on mostly-imported fossil fuels, with only 3% of total capacity and generation coming from Non- Conventional Renewable Energies (Eurostat, 2015). The use of electricity for residential heating could be a good choice because this source would reduce the environmental impact produced by PM 2.5; however, the high prices of this commodity play against this alternative.
Therefore, in this study, it is analyzed the environmental impact of using electricity for residential heating, as well as the impact of a higher contribution of solar energy in the SIC. A Life Cycle Analysis is conducted in order to compare its environmental impact. A beneficial result could bring greater implementation of solar energy for electricity usage and residential heating. This analysis will also provide some basis for the development of future incentive programs, that encourage the use of cleaner energies.
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1. Goal and Scope
Three different scenarios are analyzed in this study. “Scenario 1” (Figure 3) considers the heaters proposed by the “Sustainable Heating” program, shown in detail in Chapter 4, these 10 devices are based on firewood, pellets, paraffin and natural gas respectively.
Currently, there is no city in the Central-Southern Chile that uses electricity as its primary source of heat, even in small fractions. Therefore, “Scenario 2” proposes a higher percentage of electricity for residential heating.
Finally, “Scenario 3” represents the same participation of electricity for residential heating as Scenario 2, but a higher contribution of solar energy in the SIC grid is proposed.
The goal is to estimate the environmental impact of switching from firewood-based residential heating to electricity, on the one hand, considering the current SIC network energy matrix, on the other, with a higher contribution of solar energy.
For all the scenarios, this study considers the emissions from the production of high voltage electricity in power plants in Chile to the transmission/distribution at residential level. The streamlined life cycle of heating systems, consists in the production and transportation of the fuel required.
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Figure 3. Scenarios 1 and 2
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Functional Unit
The functional unit (FU) will be the residential consumption of 1 MWh of heat. A combination of heating technologies per city will be assumed based on previous studies made in the country.
Boundaries
The dotted line in Figures 3 and 4 represents the system's boundary. On the one hand, this analysis starts from the production of electricity in the SIC grid to the distribution of this energy to the households, considering all the transmission losses. However, the raw materials required for this process are not part of the study, as well as the power plants construction and infrastructure.
On the other hand, this analysis starts from the harvesting/chipping and transportation of firewood to the households, and also the intermediate processes of different fuels for the most commonly used heating devices.
Because the greatest populations affected by air pollution in Chile are located in the CentralSouthern cities, this study will focus on Rancagua, San Fernando, Rengo, Talca, Concepcion, Los Angeles, Temuco, Valdivia and Puerto Montt, which are also connected to the SIC network. However, the results of this analysis are expected to be applicable to other areas with critical pollution levels. One such city is Coyhaique, in the Aysén region, where the interconnection of the SIC-Aysén systems may become a reality one day, or to enhance the development of micro grids.
2. Energy Matrix of Chile
2.1 SIC Grid
The main electrical systems in Chile are the Large Northern Interconnected System (SING- Sistema Interconectado del Norte Grande), and the Central Interconnected System (SIC- Sistema Interconectado Central), which represent 99% of the total installed capacity in the country. The Aysén and Magallanes electric systems in the south are much smaller and have several not interconnected subsystems, whose existence is because geographical isolation, making them very expensive to interconnect with the SIC (Central Energia, 2015).
The SIC grid supplies power to the central and most densely populated regions of Chile. This system has an installed capacity of 15.2 GW (20 GW is the installed capacity SIC-SING) and a total load of 52.9 TWh (72 TWh is the total load in both SIC-SING). Currently, 51% of the installed capacity corresponds to thermoelectric power plants (mainly coal, natural gas and oil), 40% hydro, 5% wind and 4% solar (CDEC SIC, 2016).
The location of the cities with similar air pollution issues, are shown in the red circles in Figure 7. All of them are connected to the SIC, and therefore, the environmental impact of electricity production/distribution from different sources will be measured.
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Figure 7. Map ofSIC grid CDEC (2016)
As mentioned before, the study aims to analyze the environmental impact that could bring the implementation of electricity and particularly solar energy in residential heating. It is proposed the north of the SIC grid as a location for a solar plant as is shown in Figure 8, due to the northern area of the central region covered by the SIC receives similar levels of global horizontal irradiance (GHI) as the north (Chilesol, 2014). This may be very beneficial given that the SIC has had several power cuts in the last decade, the most notable being in 2008 due to the severe drought that substantially affected the hydro-dominated SIC distribution.
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Figure 8. Northern area ofSIC grid CDEC(2016)
2.2 Transmission losses
In order to calculate the energy required to distribute the electricity to the customers in every city, it is important to consider the transmission losses in the system.
Data from the World Bank shows a 5% of electric power transmission and distribution losses in 2012 as is shown in Figure 9, this include losses in transmission between sources of supply and points of distribution and in the distribution to consumers, including pilferage. However, for this analysis, 8% of losses will be assumed considering the trend of the past 10 years. A sensitivity analysis on this value could be made in order to assess the variability of the results.
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Figure 9. Electric power transmission and distribution losses in Chile World Bank (2014)
2.3 Energy required per functional unit
The main technologies for electricity production in the SIC grid are detailed below. As explained before, at the moment no city uses electricity for residential heating, or very low fractions which is insignificant compared with firewood usage, however, this situation will be compared with energy supply from the SIC grid in the Scenario 2, considering the current contribution of those power plants. In addition, Scenario 3 proposes a 30% contribution of solar energy to the grid, reducing the current dependency on fossil fuels.
Table 1. Contribution to electricity production in Scenario 2 and 3
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3. Heating systems in Chile
3.1 Air Pollution from wood burning
According to the Ministry of the Environment (MMA), in Chile 68% of the household energy consumption per month is for heating (MMA, 2016). Most of the current heating technologies are responsible for reaching harmful emissions levels, which affects not only the environment but also the human health; only in the Metropolitan Region of Santiago, it accounts for 30% of the pollutants (MMA, 2016).
Electric heating is one of the cleanest systems but the high cost of electricity discourages families to prefer this technology, while wood has been broadly used in Chile.
The government has implemented some initiatives to mitigate this situation:
- Restriction in the use of firewood systems when the pollutants concentration exceeds the permitted levels. This temporary solution affects the life quality of people because the indoor temperature does not reach the minimum standard of comfort.
- Prohibition of physical activity in open spaces.
- Children, pregnant women, older adults and chronically ill people must use masks when walking outside.
- General recommendations for the correct use of heating devices based on firewood: buying from certified sellers, ensure a correct combustion, etc.
- Subsidies in the replacement of heating systems under the program "Sustainable Heating", and improvement in the facade of homes in order to reduce heat losses.
3.2 Types of heating systems and emissions
The Sustainable Heating program suggests the best alternatives of heating technologies that complies with the legislation. This initiative encourages people to change their current heating device for a less contaminant and efficient stove. The MMA also provides a guide to decide which is the most suitable heating system for each type of home (MMA, 2016).
It is always recommended to have an A/C system but since this alternative is not affordable for the majority of the population, some suggestions are: central heating and high efficiency boilers for people living in apartments, in small homes the recommendation is using liquefied natural gas (LNG) or refined oil, only if the place has a good ventilation. In larger households, it is suggested using high power heaters (more than 5 kW) such as split heaters or natural gas stoves, LNGor paraffin stoves are also recommended, however, this alternative is more expensive.
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