(616c) Energy Sustainability: Trade-Offs of Consumption, Efficiency, and Environmental Impact

It is widely known that one of the major challenges in sustainability is energy.  We explore sustainable scenarios and trade-offs building on a previously discussed simple but rigorous model for the relationship between energy production, environmental impact, human population, gross domestic product, and energy efficiency.  The theory assumes that: (1) energy production increases gross domestic product and human population, (2) each joule of energy generated has a non-zero impact on the environment, (3) energy production decreases only with improved energy use efficiency, and (4) that the total environmental impact of energy production for 1977 represents an upper bound because in 1977 the human ecological footprint approximately equalled the World biocapacity.  Note that here we use the ecological footprint merely as a convenient means of establishing a reference point in time without further implications.  Using literature data both actual and projected for GDP, population, energy generation, and energy use efficiency, we develop Pareto curves for the necessary trade-off between environmental impact and efficiency that are necessary to maintain sustainability.  Our results indicate that by 2030 the efficiency that would be needed becomes unphysical at more than 100% if the environmental impact of producing a joule of energy remains near that in 1977.  However, modest reductions in environmental impact coupled with higher efficiency and lower levels of energy production may offer a path forward.  The Pareto curves developed during this project offer a range of choices which will be discussed in detail considering the efficiency and environmental impact of various means of energy production.  Further, setting reduction of green house gas emissions as a goal, we have computed the levels of energy production and energy use efficiency that would have to be meet in order that meet the objectives.  In summary, the large amounts energy required by modern societies pose a substantial challenge for sustainability, but we believe that with appropriate choices a path to sustainability is feasible.