Challenge clusters facing LCA in environmental decision-making—what we can learn from biofuels

Purpose Bioenergy is increasingly used to help meet greenhouse gas (GHG) and renewable energy targets. However, bioenergy’s sustainability has been questioned, resulting in increasing use of life cycle assessment (LCA). Bioenergy systems are global and complex, and market forces can result in significant changes, relevant to LCA and policy. The goal of this paper is to illustrate the complexities associated with LCA, with particular focus on bioenergy and associated policy development, so that its use can more effectively inform policymakers. Methods The review is based on the results from a series of workshops focused on bioenergy life cycle assessment. Expert submissions were compiled and categorized within the first two workshops. Over 100 issues emerged. Accounting for redundancies and close similarities in the list, this reduced to around 60 challenges, many of which are deeply interrelated. Some of these issues were then explored further at a policyfacing workshop in London, UK. The authors applied a rigorous approach to categorize the challenges identified to be at the intersection of biofuels/bioenergy LCA and policy. Results and discussion The credibility of LCA is core to its use in policy. Even LCAs that comply with ISO standards and policy and regulatory instruments leave a great deal of scope for interpretation and flexibility. Within the bioenergy sector, this has led to frustration and at times a lack of obvious direction. This paper identifies the main challenge clusters: overarching issues, application and practice and value and ethical judgments. Many of these are reflective of the transition from application of LCA to assess individual products or systems to the wider approach that is becoming more common. Uncertainty in impact assessment strongly influences planning and compliance due to challenges in assigning accountability, and communicating the inherent complexity and uncertainty within bioenergy is becoming of greater importance. Conclusions The emergence of LCA in bioenergy governance is particularly significant because other sectors are likely to transition to similar governance models. LCA is being stretched to accommodate complex and broad policy-relevant questions, seeking to incorporate externalities that have major implications for long-term sustainability. As policy increasingly relies on LCA, the strains placed on the methodology are becoming both clearer and impedimentary. The implications for energy policy, and in particular bioenergy, are large

Mantle heat drives hydrothermal fluids responsible for carbonate-hosted base metal deposits: evidence from 3He/4He of ore fluids in the Irish Pb-Zn ore district

There is little consensus on whether carbonate-hosted base metal deposits, such as the world-class Irish Zn+Pb ore field, formed in collisional or extensional tectonic settings. Helium isotopes have been analysed in ore fluids trapped in sulphides samples from the major base metal deposits of the Irish Zn-Pb ore field in order to quantify the involvement of mantle-derived volatiles, that require melting to be realised, as well as test prevailing models for the genesis of the ore fields. 3He/4He ratios range up to 0.2 Ra, indicating that a small but clear mantle helium contribution is present in the mineralising fluids trapped in galena and marcasite. Sulfides from ore deposits with the highest fluid inclusion temperatures (~200°C) also have the highest 3He/4He (> 0.15 Ra). Similar 3He/4He are recorded in fluids from modern continental regions that are undergoing active extension. By analogy we consider that the hydrothermal fluids responsible for the carbonate-hosted Irish base metal mineralization circulated in thinned continental crust, undergoing extension, and demonstrates that enhanced mantle heat flow is ultimately responsible for driving fluid convection

Achieving Deep Cuts in the Carbon Intensity of U.S. Automobile Transportation by 2050: Complementary Roles for Electricity and Biofuels

Passenger cars in the United States (U.S.) rely primarily on petroleum-derived fuels and contribute the majority of U.S. transportation-related greenhouse gas (GHG) emissions. Electricity and biofuels are two promising alternatives for reducing both the carbon intensity of automotive transportation and U.S. reliance on imported oil. However, as standalone solutions, the biofuels option is limited by land availability and the electricity option is limited by market adoption rates and technical challenges. This paper explores potential GHG emissions reductions attainable in the United States through 2050 with a county-level scenario analysis that combines ambitious plug-in hybrid electric vehicle (PHEV) adoption rates with scale-up of cellulosic ethanol production. With PHEVs achieving a 58% share of the passenger car fleet by 2050, phasing out most corn ethanol and limiting cellulosic ethanol feedstocks to sustainably produced crop residues and dedicated crops, we project that the United States could supply the liquid fuels needed for the automobile fleet with an average blend of 80% ethanol (by volume) and 20% gasoline. If electricity for PHEV charging could be supplied by a combination of renewables and natural-gas combined-cycle power plants, the carbon intensity of automotive transport would be 79 g CO2e per vehicle-kilometer traveled, a 71% reduction relative to 2013

Redo Cardiac Surgery in a Patient with Severe Peripheral Vascular Disease and Pericardia/ Adhesions Using Subclavian Arterial Cannulation and Port-Access Technology

Patients viewed as conventionally inoperative candidates are now given alternative surgical choices. The ability to provide new technology such as the port-access minimally invasive approach, kinetic venous assist, and specialized cannulae have made this possible. This case report discusses the ability to apply and modify this new technology to provide a successful surgical outcome in a patient with severe peripheral vascular disease and dense mediastinal adhesions

Domain size as a parameter for studying the potential alkali-silica reactivity of chert-bearing aggregates

The presence of chert or flint in aggregates used for concrete manufacture has long been a source of concern in the context of alkali-silica reactivity. The global in-service performance of chert and flint-bearing aggregates, however, varies from innocuous to deleterious. This could be due to variations in the degree of crystallinity of the silica, which influences potential reactivity. Chert occurs in significant Irish sources of aggregate used for concrete, yet no cases of deleterious expansion have been reported in the Republic of Ireland to date. Many of these sources fail to conclusively demonstrate innocuous behaviour in the laboratory expansion tests despite satisfactory in-service behaviour. A previous X-ray diffraction study, employing quartz crystallinity index, had indicated a significant difference between Irish Carboniferous cherts and English Cretaceous flints. This paper reports a further study of crystallinity, correlated with mortar bar expansion tests, but employing both quartz crystallinity index and domain size in the characterisation of crystallinity. The influence of chert content was also studied. Twenty-three Irish aggregate sources were sampled, and petrographic analysis revealed that 17 of these contained chert. Three flint-bearing aggregates, from sources in England that had demonstrated alkali-silica reactivity, were also sampled. Chert and flint were extracted from the aggregate samples by a petrographer experienced in the field of concrete technology. Twenty-six distinct samples were successfully extracted from 13 of the Irish and the three English sources. X-ray diffraction testing confirmed the previous findings (using the quartz crystallinity indices) that the Irish cherts are,more crystalline than the English flints. Domain size determination, however, showed that the difference in crystallinity of the national sets was less than that anticipated. The influence of chert content is advanced as a hypothesis to explain the apparent reactivity of Irish cherts in screening tests. The potential value of combining domain size and chert content determination in helping to classify aggregate reactivity is advanced for cases where in-service behaviour is in significant conflict with findings from standard laboratory tests.Other funderIrish Cement Ltd"Full acknowledgement to source and publisher must be given. Please link to website: http://www.icevirtuallibrary.com/ ". Publiher version - http://www.icevirtuallibrary.com/content/article/10.1680/macr.2004.56.4.201. DG 29/07/10 au,ke.kpw25/8/1

Feasibility of Achieving a Zero-Net-Energy, Zero-Net-Cost Homes

A green building competition, to be known as the Energy Free Home Challenge (EFHC), is scheduled to be opened to teams around the world in 2010. This competition will encourage both design innovation and cost reduction, by requiring design entries to meet 'zero net energy' and 'zero net cost' criteria. For the purposes of this competition, a 'zero net energy' home produces at least as much energy as it purchases over the course of a year, regardless of the time and form of the energy (e.g., electricity, heat, or fuel) consumed or produced. A 'zero net cost' home is no more expensive than a traditional home of comparable size and comfort, when evaluated over the course of a 30-year mortgage. In other words, the 'green premium' must have a payback period less than 30 years, based on the value of energy saved. The overarching goal of the competition is to develop affordable, high-performance homes that can be mass-produced at a large scale, and are able to meet occupant needs in harsh climates (as can be found where the competition will be held in Illinois). This report outlines the goals of the competition, and gauges their feasibility using both modeling results and published data. To ensure that the established rules are challenging, yet reasonable, this report seeks to refine the competition goals after exploring their feasibility through case studies, cost projections, and energy modeling. The authors of this report conducted a survey of the most progressive home energy-efficiency practices expected to appear in competition design submittals. In Appendix A, a summary can be found of recent projects throughout the United States, Canada, Germany, Switzerland, Sweden and Japan, where some of the most progressive technologies have been implemented. As with past energy efficient home projects, EFHC competitors will incorporate a multitude of energy efficiency measures into their home designs. The authors believe that the cost of electricity generated by home generation technologies will continue to exceed the price of US grid electricity in almost all locations. Strategies to minimize whole-house energy demand generally involve some combination of the following measures: optimization of surface (area) to volume ratio; optimization of solar orientation; reduction of envelope loads; systems-based engineering of high efficiency HVAC components, and on-site power generation. A 'Base Case' home energy model was constructed, to enable the team to quantitatively evaluate the merits of various home energy efficiency measures. This Base Case home was designed to have an energy use profile typical of most newly constructed homes in the Champaign-Urbana, Illinois area, where the competition is scheduled to be held. The model was created with the EnergyGauge USA software package, a front-end for the DOE-2 building energy simulation tool; the home is a 2,000 square foot, two-story building with an unconditioned basement, gas heating, a gas hot-water heater, and a family of four. The model specifies the most significant details of a home that can impact its energy use, including location, insulation values, air leakage, heating/cooling systems, lighting, major appliances, hot water use, and other plug loads. EFHC contestants and judges should pay special attention to the Base Case model's defined 'service characteristics' of home amenities such as lighting and appliances. For example, a typical home refrigerator is assumed to have a built-in freezer, automatic (not manual) defrost, and an interior volume of 26 cubic feet. The Base Case home model is described in more detail in Section IV and Appendix B