Energy return on investment of major energy carriers: Review and harmonization

Net energy, that is, the energy remaining after accounting for the energy “cost” of extraction and processing, is the “profit” energy used to support modern society. Energy Return on Investment (EROI) is a popular metric to assess the profitability of energy extraction processes, with EROI > 1 indicating that more energy is delivered to society than is used in the extraction process. Over the past decade, EROI analysis in particular has grown in popularity, resulting in an increase in publications in recent years. The lack of methodological consistency, however, among these papers has led to a situation where inappropriate comparisons are being made across technologies. In this paper we provide both a literature review and harmonization of EROI values to provide accurate comparisons of EROIs across both thermal fuels and electricity producing technologies. Most importantly, the authors advocate for the use of point-of-use EROIs rather than point-of-extraction EROIs as the energy “cost” of the processes to get most thermal fuels from extraction to point of use drastically lowers their EROI. The main results indicate that PV, wind and hydropower have EROIs at or above ten while the EROIs for thermal fuels vary significantly, with that for petroleum oil notably below ten

Comparative net energy analysis of renewable electricity and carbon capture and storage

Carbon capture and storage (CCS) for fossil-fuel power plants is perceived as a critical technology for climate mitigation. Nevertheless, limited installed capacity to date raises concerns about the ability of CCS to scale sufficiently. Conversely, scalable renewable electricity installations—solar and wind—are already deployed at scale and have demonstrated a rapid expansion potential. Here we show that power-sector CO2 emission reductions accomplished by investing in renewable technologies generally provide a better energetic return than CCS. We estimate the electrical energy return on energy invested ratio of CCS projects, accounting for their operational and infrastructural energy penalties, to range between 6.6:1 and 21.3:1 for 90% capture ratio and 85% capacity factor. These values compare unfavourably with dispatchable scalable renewable electricity with storage, which ranges from 9:1 to 30+:1 under realistic configurations. Therefore, renewables plus storage provide a more energetically effective approach to climate mitigation than constructing CCS fossil-fuel power stations

On the reporting and review requirements of ISO 14044

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Life cycle assessment of emerging technologies: Evaluation techniques at different stages of market and technical maturity

Life cycle assessment (LCA) analysts are increasingly being asked to conduct life cycleâ based systems level analysis at the earliest stages of technology development. While early assessments provide the greatest opportunity to influence design and ultimately environmental performance, it is the stage with the least available data, greatest uncertainty, and a paucity of analytic tools for addressing these challenges. While the fundamental approach to conducting an LCA of emerging technologies is akin to that of LCA of existing technologies, emerging technologies pose additional challenges. In this paper, we present a broad set of market and technology characteristics that typically influence an LCA of emerging technologies and identify questions that researchers must address to account for the most important aspects of the systems they are studying. The paper presents: (a) guidance to identify the specific technology characteristics and dynamic market context that are most relevant and unique to a particular study, (b) an overview of the challenges faced by early stage assessments that are unique because of these conditions, (c) questions that researchers should ask themselves for such a study to be conducted, and (d) illustrative examples from the transportation sector to demonstrate the factors to consider when conducting LCAs of emerging technologies. The paper is intended to be used as an organizing platform to synthesize existing methods, procedures and insights and guide researchers, analysts and technology developer to better recognize key study design elements and to manage expectations of study outcomes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154465/1/jiec12954-sup-0001-SuppMat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154465/2/jiec12954.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154465/3/jiec12954_am.pd

Visualizing Relative Potential for Aquatic Ecosystem Toxicity Using the EPA Toxics Release Inventory and Life Cycle Assessment Methods

The U.S. EPA Toxic Release Inventory has been available since 1987 as a record of industrial releases of toxic chemicals following the 1986 Emergency Planning and Community Right-to-Know Act. Combining this release data with estimates of relative toxicity of these chemicals to aquatic systems increases the value of the database by providing a common basis for comparison. The Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts is a database of characterization factors to assess environmental impacts. It was used to develop relative ecotoxicity impacts and interpreted using Life Cycle Assessment concepts. The visualization software Tableau was used to generate representations of the preliminary results in this communication. The major potential sources of aquatic toxicity have been identified for South Carolina by industry type and by year over the period 1987–2016. The possibility of toxicity from releases of zinc compounds from power generation and pulp and paper mills far exceeds all other sources. Zinc compounds dominated the potential ecotoxicity over the full time period 1987–2016

Comparing Apples to Apples: Why the Net Energy Analysis Community Needs to Adopt the Life-Cycle Analysis Framework

How do we know which energy technologies or resources are worth pursuing and which aren’t? One way to answer that question is to compare the energy return of a certain technology—i.e., how much energy is remaining after accounting for the amount of energy expended in the production and delivery process. Such energy return ratios (the most famous of which is energy return on investment (EROI)) fall within the field of net energy analysis (NEA), and provide an easy way to determine which technology is “better”; i.e., higher Energy Return Ratios (ERRs) are, certeris paribus, better than lower ERRs. Although useful as a broad measure of energy profitability, comparisons can also be misleading, particularly if the units being compared are different. For example, the energy content of electricity produced from a photovoltaic cell is different than the energy content of coal at the mine-mouth, yet these are often compared directly within the literature. These types of inconsistencies are common within the NEA literature. In this paper, we offer life cycle assessment (LCA) and the LCA methodology as a possible solution to the persistent methodological issues within the NEA community, and urge all NEA practitioners to adopt this methodology in the future

Disease Risk & Landscape Attributes of Tick-Borne Borrelia Pathogens in the San Francisco Bay Area, California

Habitat heterogeneity influences pathogen ecology by affecting vector abundance and the reservoir host communities. We investigated spatial patterns of disease risk for two human pathogens in the Borrelia genus–B. burgdorferi and B. miyamotoi–that are transmitted by the western black-legged tick, Ixodes pacificus. We collected ticks (349 nymphs, 273 adults) at 20 sites in the San Francisco Bay Area, California, USA. Tick abundance, pathogen prevalence and density of infected nymphs varied widely across sites and habitat type, though nymphal western black-legged ticks were more frequently found, and were more abundant in coast live oak forest and desert/semi-desert scrub (dominated by California sagebrush) habitats. We observed Borrelia infections in ticks at all sites where we able to collect >10 ticks. The recently recognized human pathogen, B. miyamotoi, was observed at a higher prevalence (13/349 nymphs = 3.7%, 95% CI = 2.0–6.3; 5/273 adults = 1.8%, 95% CI = 0.6–4.2) than recent studies from nearby locations (Alameda County, east of the San Francisco Bay), demonstrating that tick-borne disease risk and ecology can vary substantially at small geographic scales, with consequences for public health and disease diagnosis

A bio-physical and net-energy comparison of CCS and renewable energy baseload systems

While CCS is considered a key component for climate change mitigation, actual installed capacity to date creates concerns about its ability to scale sufficiently fast. In the face of this lag, a considered complementary trajectory is for CCuS to play a role in later phases as a way to actively reduce CO2 emissions in combination with biomass. This paper discusses an alternative option: under which circumstances would simply eschewing fossil-based CCS and readily switching the energy system to abundant renewable energy (RE) resources be preferable? We discuss the relative merits of CCS vs RE investments using net-energy as the primary metric but also provide ancillary considerations on the utilization pathway, geological, and infrastructural requirements Please click Additional Files below to see the full abstract

A bio-physical and net-energy comparison of CCS and renewable energy baseload systems

While CCS is considered a key component for climate change mitigation, actual installed capacity to date creates concerns about its ability to scale sufficiently fast. In the face of this lag, a considered complementary trajectory is for CCuS to play a role in later phases as a way to actively reduce CO2 emissions in combination with biomass. This paper discusses an alternative option: under which circumstances would simply eschewing fossil-based CCS and readily switching the energy system to abundant renewable energy (RE) resources be preferable? We discuss the relative merits of CCS vs RE investments using net-energy as the primary metric but also provide ancillary considerations on the utilization pathway, geological, and infrastructural requirements Please click Additional Files below to see the full abstract