Carbon Footprint. Carbon Footprint: some defini7ons

Transcription

1 Carbon Footprint CE 5515: Sustainable Design and Construction Dr. Andrea Schokker Carbon Footprint: some defini7ons Carbon footprint: the total CO 2 and other greenhouse gas emissions produced directly or indirectly from an item or process Carbon neutral / zero footprint: having a net zero carbon footprint (no overall CO 2 produced or reduced) Carbon nega3ve: having a net nega7ve carbon footprint (overall reduc7on in CO 2 ) Embodied energy: energy embodied in the physical building including raw materials, transport, manufacture, and later demoli7on Opera3onal energy: Energy needed for building func7ons including hea7ng, cooling, and ligh7ng 1

2 Life Cycle Assessment (LCA): the quan7fica7on of the full environmental impacts of a building (or product or service) over its life7me, not to be confused with Life cycle cost (LCC) which includes only the monetary impact Cradle- to- grave: LCA considering manufacture or birth (cradle) through demoli7on (grave) Cradle- to- cradle: an extension of cradle- to- grave to include recycle/reuse of the materials to bring the cycle back to the cradle (birth) Ecocalculator: tool for LCA calcula7ons to evaluate poten7al to contribute to global warming Carbon Footprint Measures the poten7al contribu7on humans have on climate change expressed in weight of CO 2 equivalent Emissions from manufacture of a product Extrac7on of resources Burning of fossil fuels to manufacture Transport of raw materials and final product Emissions from a product s con7nued use, opera7on, and maintenance 2

3 Carbon Footprint of a T- Shirt coson harvested, shipped yarn spun, shipped cloth made, shipped shirt made, shirt shipped for distribu7on shipped to store washed over the lifespan (7 of footprint - air dry?) Disposal or RRR Map of Carbon Emissions in millions of metric tons/year/100 sq km (courtesy of the Vulcan Project, 2002 data) 3

4 Greenhouse gas emissions by industrial sector plas7c and rubber 2% alumina & aluminum 3% mining iron & steel forest products construc7on cement food & bev 4% tex7les 2% lime 1% other sectors 14% metal cas7ngs 1% semiconductors 1% oil & gas 31% chemicals 16% Embodied vs Opera7onal CO 2 Courtesy of GGLO (based on SeaSle districts): 4

5 Embodied Carbon Embodied is ¼ of total at 30 years (~10% at 100 years) As buildings are more efficient, embodied is greater % and more important renova7on Courtesy of GGLO (based on SeaSle districts): Carbon Labeling T- shirt cement Cemex cement = 17 kg / 25 kg bag (or 0.68 kg / kg cement) Potato Chips (Walker s crisps) = 80 g / 34.5 g bag (or 2.31 kg / kg chips) 5

6 Fuel economy and CO2 informa9on on car labels in the U.K. à Emissions directly relate to level of taxes paid on the car Cement Second most used aher water and by far the most- used building material worldwide CO 2 emissions from cement manufacture Generally accepted as 4- of world total; 1. of US total About 50% from burning limestone and 50% from fuel needed to run the kiln Raw Materials Grinding & Blending Burning Milling Packaging / Distribu7on Quarrying and crushing of limestone, shale, clay, and other raw materials Grinding of raw materials Blending Materials may be preheated to reduce energy Primary burning in kiln Clinker exits kiln and cools Add gypsum Grinding clinker to form cement powder Stored in silos, bagged 6

7 Cement Manufacture Wet process: slurry to kiln (then needs heat to dry) Dry process: dry to kiln Image from See PCA site for flash tour of how cement in manufactured hsp:// Concrete vs Cement About 1/10 of concrete is cement even if no supplementary cemen77ous materials are used SCMs ohen replace 5-40% of the cement in a mixture (and some7mes more) 7

8 SCMs (Supplementary Cemen77ous Materials) Fly Ash By- product of coal- fired plants that generate electricity Silica Fume By- product of silicon metal and ferrosilicon produc7on Slag cement By- product of iron produc7on Others: volcanic ash, rice husk ash, metakaolin Ternary blends (2 SCMs per mixture) Hazardous materials classifica7on by EPA being considered Recycled materials points for LEED and not only reuse by- products/waste, but also improve concrete proper7es; not a new thing for concrete 8