Emergy-based Simulation to Assess Brazil’s Long-term Carrying Capacity: Environment, Electricity and Population

Abstract

A macroscopic mini-model of Brazil's electrical generating capacity (BRAZ-ELECTRIX, Brazilian Electricity Matrix) was developed using the Energy Systems Language and simulated with iconographic ExtendÒ software to explore long-term (200 years) population carrying capacity. South American reserves of natural gas (NG) and Brazilian stream hydro-power potential were assumed as the main inputs to electric power production. Energy values (e.g., kWh, joules) for fuels, electricity and environment were transformed to solar emergy (i.e., solar equivalent joules) to simplify cross comparison with a single metric. BRAZELECTRIX was calibrated using a holistic method that used mean component life-times and conservation of material and energy for each individual unit. Validation of BRAZELECTRIX, based on historical data, gave a root mean square error of 8% for hydroelectricity and 28% for natural gas use. Investments in natural gas infrastructure (e.g., contracts, pipelines, processing plants and electric power plants) accelerated Brazil's expansion of electrical generating capacity for a finite period, allowing the country to reach its renewable (hydro-power only) carrying capacity 100 years sooner than without (2040 vs. 2140). Brazil has a total of 560 zetta-solar equivalent joules per annum (1 Zseja = 1 ·10 21 sej per year) of stream hydro-power potential; 170 Zseja is currently used for electricity generation. According to BRAZELECTRIX, eventually 390 Zseja will be tapped for hydroelectricity. The standard of living, as measured by annual per capita electrical solar emergy, had risen 680% from 166 tera-solar equivalent joules (Tseja) to 1130 Tseja during the 35 year period following 1965 and was predicted to increase another 75% to its maximum (1973 Tseja) in 2050. By comparison, an urbanizing state of the United States (North Carolina) had an annual per capita electrical solar emergy of 7815 Tseja in 1992, indicating that Brazil could reach a living standard, as measured by per 123 capita electricity usage, equal to one-forth the level of United States. Macroscopic minimodels combined with emergy accounting evaluated long-term paths for Brazil's electricity supply and related it to natural environment trade-offs to demonstrate how sustainable carrying capacity of a developing nation can be forecast.

Emergy and Economic Evaluation of Seven Typical Agroforestry Planting Patterns in the Karst Region of Southwest China

“…Emergy analysis theory, which can convert all kinds of different categories of energy and matter to the same standard values, was first proposed for quantitative analysis in the 1990s [17]. This theory was widely used to solve the energy unit-inconformity in different nature or social systems; to measure the real value of the natural environment resources and economic activities; to analyze the relationship among components of a complex system, to harmonize ecological protection and economic and social development [18][19][20][21]. In recent decades, there have been many applications of this theory on the input-output analysis of agricultural ecosystems [22,23] to assess the level of social sustainable development [24], dynamic analysis [25,26], scenario forecasting [27].…”

Study on the Sustainability of Hefei City Economic Ecosystem Based on Emergy Analysis

“…In measure of the sustainable development of urban ecosystem, the balance of emergy will be more important. If the output emergy left the local are more than the input, the regional economy is not sustainable [4] . In 2010, the input emergy ( R+F ) of eco-economic system of Hefei city was 2.35×10 22 sej, the output emergy (Y+N) was 1.95×10 22 sej, the surplus emergy was 0.40×10 22 sej, accounting for 17.02% of the applied emergy, which indicated that the emergy of Hefei city continued to increase and accumulate, and this was the real reason of the rapid development of Hefei city in recent years.…”