Carbon and cost critical elements of buildings : a comparative analysis of two office buildings

Purpose: The aim of this paper is to identify and compare cost and carbon critical elements of two office buildings and to propose an early design stage cost and carbon control strategy to achieve an optimum balance between building Capital Cost (CC) and Embodied Carbon (EC). Design/methodology/approach: Case study approach was employed to identify cost and carbon critical elements of two office buildings as it allows an in-depth and holistic investigation. Elemental estimates of CC and EC were prepared from BoQs of the two office buildings by obtaining rates from the UK Building Blackbook. Pareto Principle (80:20 rule) was used to identify carbon and cost critical elements of the two buildings and the significance hierarchies of building elements were compared. Findings: Substructure, Frame and Services were identified as both carbon and cost critical elements responsible for more than 70% of the total CC and EC in both buildings. Stairs and Ramps, Internal Doors and Fittings, Furnishings and Equipment were identified to be the least carbon and cost significant elements contributing less than 2% of total CC and EC in both buildings. The hierarchy of cost and carbon significance varies between buildings due to the difference in the specification and design. Originality/value: The increasing significance of dual currency (cost and carbon) demands cost and carbon management during the early stages of project. Hence, this paper suggests that focusing on carbon and cost intensive building elements is a way forward to keep both cost and carbon under control during the early stages of projects. Keywords: Carbon Hotspots, Capital Cost, Cost Hotspots, Embodied Carbon, Office Buildings

Carbon stored in human settlements: the conterminous United States

Urban areas are home to more than half of the world's people, responsible for >70% of anthropogenic release of carbon dioxide and 76% of wood used for industrial purposes. By 2050 the proportion of the urban population is expected to increase to 70% worldwide. Despite fast rates of change and potential value for mitigation of carbon dioxide emissions, the organic carbon storage in human settlements has not been well quantified. Here, we show that human settlements can store as much carbon per unit area (23–42 kg C m −2 urban areas and 7–16 kg C m −2 exurban areas) as tropical forests, which have the highest carbon density of natural ecosystems (4–25 kg C m −2 ). By the year 2000 carbon storage attributed to human settlements of the conterminous United States was 18 Pg of carbon or 10% of its total land carbon storage. Sixty-four percent of this carbon was attributed to soil, 20% to vegetation, 11% to landfills, and 5% to buildings. To offset rising urban emissions of carbon, regional and national governments should consider how to protect or even to increase carbon storage of human-dominated landscapes. Rigorous studies addressing carbon budgets of human settlements and vulnerability of their carbon storage are needed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75157/1/j.1365-2486.2009.02002.x.pd

Actively forming Kuroko-type volcanic-hosted massive sulfide (VHMS) mineralization at Iheya North, Okinawa Trough, Japan

Modern seafloor hydrothermal systems provide important insights into the formation and discovery of ancient volcanic-hosted massive sulfide (VHMS) deposits. In 2010, Integrated Ocean Drilling Program (IODP) Expedition 331 drilled five sites in the Iheya North hydrothermal field in the middle Okinawa Trough back-arc basin, Japan. Hydrothermal alteration and sulfide mineralization is hosted in a geologically complex, mixed sequence of coarse pumiceous volcaniclastic and fine hemipelagic sediments, overlying a dacitic to rhyolitic volcanic substrate. At site C0016, located adjacent to the foot of the actively venting North Big Chimney massive sulfide mound, massive sphalerite-(pyrite-chalcopyrite ± galena)-rich sulfides were intersected (to 30.2% Zn, 12.3% Pb, 2.68% Cu, 33.1 ppm Ag and 0.07 ppm Au) that strongly resemble the black ore of the Miocene-age Kuroko deposits of Japan. Sulfide mineralization shows clear evidence of formation through a combination of surface detrital and subsurface chemical processes, with at least some sphalerite precipitating into void space in the rock. Volcanic rocks beneath massive sulfides exhibit quartz-muscovite/illite and quartz-Mg-chlorite alteration reminiscent of VHMS proximal footwall alteration associated with Kuroko-type deposits, characterized by increasing MgO, Fe/Zn and Cu/Zn with depth. Recovered felsic footwall rocks are of FII to FIII affinity with well-developed negative Eu anomalies, consistent with VHMS-hosting felsic rocks in Phanerozoic ensialic arc/back-arc settings worldwide. Site C0013, ∼100 m east of North Big Chimney, represents a likely location of recent high temperature discharge, preserved as surficial coarse-grained sulfidic sediments (43.2% Zn, 4.4% Pb, 5.4% Cu, 42 ppm Ag and 0.02 ppm Au) containing high concentrations of As, Cd, Mo, Sb, and W. Near surface hydrothermal alteration is dominated by kaolinite and muscovite with locally abundant native sulfur, indicative of acidic hydrothermal fluids. Alteration grades to Mg-chlorite dominated assemblages at depths of >5 mbsf (metres below sea floor). Late coarse-grained anhydrite veining overprints earlier alteration and is interpreted to have precipitated from down welling seawater as hydrothermal activity waned. At site C0014, ∼350 m farther east, hydrothermal assemblages are characterized by illite/montmorillonite, with Mg-chlorite present at depths below ∼30 mbsf. Recovered lithologies from distal, recharge site C0017 are unaltered, with low MgO, FeO and base metal concentrations. Mineralization and alteration assemblages are consistent with the Iheya North system representing a modern analogue for Kuroko-type VHMS mineralization. Fluid flow is focussed laterally along pumiceous volcaniclastic strata (compartmentalized between impermeable hemipelagic sediments), and vertically along faults. The abundance of Fe-poor sphalerite and Mg-rich chlorite (clinochlore/penninite) is consistent with the lower Fe budget, temperature and higher oxidation state of felsic volcanic-hosted hydrothermal systems worldwide compared to Mid Ocean Ridge black smoker systems

Carbon footprint of polycrystalline photovoltaic systems

The environmental and energy parameters of Photovoltaic (PV) systems play a very important role when compared to conventional power systems. In the present paper, a typical PV-system is analyzed to its elements and an assessment of the material and energy requirements during the production procedures is attempted. A Life Cycle Analysis (LCA) is being performed on the production system of photovoltaics. Energy and environmental analyses are extended to the production of the primary energy carriers. This allows having a complete picture of the life cycle of all the PV-components described in the present study. Four different scenarios are examined in detail providing every possible aspect of scientific interest involving polycrystalline PV systems. In order to obtain concrete results from this study, the specific working tool used is the Eco-Indicator ’95 (1999) as being reliable and widely applied and accepted within LCA community. A process that relates inventory information with relevant concerns about natural resource usage and potential effects of environmental loadings is attempted. Large-scale PV-systems have many advantages in comparison with a conventional power system (e.g. diesel power station) in electricity production. As a matter of fact, PV-systems become part of the environment and the ecosystems from the moment of their installation. Carbon Footprints of various PV-systems scenarios are greatly smaller than that of a diesel power station operation. Further technological improvements in PV module production and in the manufacture of Balance-of-System components, as well as extended use of renewable energy resources as primary energy resources could make Carbon Footprint of PV-systems even smaller. Extended operational period of time (O.P.T.) of PV-systems determined by system reliability should be given special attention, because it can dramatically mitigate energy resources and raw materials exploitation

Economic incentives and disincentives for recycling of municipal solid waste

This report is divided into an Executive Summary and four chapters. These chapters examine Federal subsidies to virgin materials, the potential for Federal subsidies for recycled materials, Federal subsidies for alternative energy sources, and state efforts at increasing recycling through tax incentives