Analysis of Energy, Carbon, and Nutrients Through 1,800 Households In the Twin Cities

In post-industrial cities large proportions of inputs of energy, carbon, and nutrients enter via households.  To quantify these fluxes, we developed a hybrid survey approach to analyze fluxes through 1,800 household systems in the Twin Cities Household Ecosystem Project.  Survey results show that the distributions of both total and component fluxes among households are highly skewed (disproportionate), with a small percentage of households accounting for large percentage of the total flux.  For example, 20% of households accounted for 35% of C emissions associated with home heating, 40% of emissions associated with driving, and 75% of emissions for air travel.  A major influence on household energy and carbon emissions was the number of residents: total fluxes increased with increasing household size, but per capita fluxes decreased. With regard to income, 88% of households with > $200,000 income were in the upper two quintiles for carbon emissions, compared with only 21% of households with incomes < $50,000.  Among households in the income range of $50,000-$99,000, we observed nearly even distributions among carbon emissions quintiles, suggesting considerable flexibility in behaviors associated with carbon emissions.  Analysis of household-level energy and carbon emissions data can help to inform behavior-based conservation policies.