Follow the Flow

FUEL SUPPLY Fossil fuels continue to satisfy nearly all of the United States'energy demands. The potential forrenewables to replace those fuels is still mostly unrealized. SECTOR DEMAND AND END USES Nearly half of thenation's primary fuel supplyis used to generate electricity. The restisused to power vehicles and heat buildings, and as feedstocks for the chemicalindustry. WINS AND LOSSES Mostheatloss occurs during electricity generation, but a lotis alsolostininternal-combustion engines. Thermoelectricdevices could eventually beused to convert some ofthat waste heat into electricity. GRAPHITI 84.8% FOSSIL FUELS 28.6% TRANSPORT 39.2% Petroleum 13.8% Waste heat from internal- combustion engines 28 44.6% WASTE HEAT Primary fuels 17.9% Lost in conver- Ground transportation Follow the Flow sion from chemical to mechanical energy THE TRAIL OF U.S. ENERGY-WHAT Aviation/marine/pipelines 0.1% Electricity (secondary fuel) WE USE, AND HOW WE WASTE IT Electric transport 26.7% Lost in conver- sion from chemical to 23.3% Natural gas electrical energy Industrial waste heat fyoutried to get an all-embracing Iview ofenergy use in the United States, it wouldn't take long for your eyes to go blurry. The Energy Informa- tion Administration and other sources 31.4% INDUSTRIAL Commercial and residential 20.9% 22.4% Primary fuels Feedstocks release reams of data almost constantly. Coal That's good if you want to look at minute detail, but not so good if you want the big picture. Based on a version originally cre- Steam generation, facil- ity heating and cooling, ventilation, lighting, and other uses 3.4% Electricity 7.2% Allocated waste heat from electricity generation* 55.5% UTILIZED ated by researcher David Bassett for the Woodrow Wilson Center, this energy 8.3% NUCLEAR 41.6% Used directly as fuel for vehicles, feedstocks for indus- flow map reveals the energy sources we draw from, the ways we use that energy, trial products, and heat sources for residen- tial and commercial 17.8% COMMERCIAL and the ways we waste it. Two elements 3.6% Combined loss from are perhaps most striking: at bottom left, the relativelypaltry contribution of renewables; and at far right, the stagger- ing amount of energy lost as heat. On its own, this lost energy could satisfy 6.7% RENEWABLES electricity generation 4.5% buildings 40.6% 9.6%* ELECTRICITY GENERATION 0.1% IMPORTED the total demands of an industrialized ELECTRICITY nation like Japan or Germany. of this kind in December 1990, while working Heating, ventilation, cooling, and lighting 13.9% Output as elec- tricity from power plants Bassett created his first map 21.3% RESIDENTIAL 6.7% in the pollution prevention division of the U.S. Environmental Protection 4.7% Electricity Other uses Agency. When asked to update it to illuminate the current debate over CURRENT 9.9%* TYPE SUPPLY energy policy, he jumped at the chance-but was dismayed when he compared the results with what he'd found two decades ago. "Aside from an Biomass 3.3% *Proportion of waste heat attributed to the generation ofelectricity for eacheconomic sector. Hydroelectric 2.7 Geothermal 0.4 Notes: Data for 2007. Percentages based onquadril- lion BTU equivalents. Because of rounding and dis- crepancies between sources, figuresdo not total 100%. Wind 0.3 1.3% POWER DELIVERY increase in scale, they look much the Solar 0.1 Transmission and delivery losses same," he said. "It's sobering to realize how little we've been able to do to put this lost heat to use." –Matt Mahoney Industrial waste 0.01 Sources: DOE Energy Information Administration. Based on chart prepared by David Bassett for the Woodrow Wilson International Center for Scholars Information graphic by TOMMY MCCALL and DAVID BASSETT and the Emvironmental Law Institute. 32 GRAPHITI TECHNOLOGY REVIEW MAY/JUNE 2010 www.TECHNOLOGYREVIEW.COM GRAPHITI 33