The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform

Sally M Benson - One of the best experts on this subject based on the ideXlab platform.

  • Hydrogen or batteries for grid storage? A Net Energy Analysis
    Energy and Environmental Science, 2015
    Co-Authors: Matthew A. Pellow, Charles J. Barnhart, Christopher J.m. Emmott, Sally M Benson
    Abstract:

    Energy storage is a promising approach to address the challenge of intermittent generation from renewables on the electric grid. In this work, we evaluate Energy storage with a regenerative hydrogen fuel cell (RHFC) using Net Energy Analysis. We examine the most widely installed RHFC configuration, containing an alkaline water electrolyzer and a PEM fuel cell. To compare RHFC's to other storage technologies, we use two Energy return ratios: the electrical Energy stored on invested (ESOIe) ratio (the ratio of electrical Energy returned by the device over its lifetime to the electrical-equivalent Energy required to build the device) and the overall Energy efficiency (the ratio of electrical Energy returned by the device over its lifetime to total lifetime electrical-equivalent Energy input into the system). In our reference scenario, the RHFC system has an ESOIe ratio of 59, more favorable than the best battery technology available today (Li-ion, ESOIe = 35). (In the reference scenario RHFC, the alkaline electrolyzer is 70% efficient and has a stack lifetime of 100000 h; the PEM fuel cell is 47% efficient and has a stack lifetime of 10000 h; and the round-trip efficiency is 30%.) The ESOIe ratio of storage in hydrogen exceeds that of batteries because of the low Energy cost of the materials required to store compressed hydrogen, and the high Energy cost of the materials required to store electric charge in a battery. However, the low round-trip efficiency of a RHFC Energy storage system results in very high Energy costs during operation, and a much lower overall Energy efficiency than lithium ion batteries (0.30 for RHFC, vs. 0.83 for lithium ion batteries). RHFC's represent an attractive investment of manufacturing Energy to provide storage. On the other hand, their round-trip efficiency must improve dramatically before they can offer the same overall Energy efficiency as batteries, which have round-trip efficiencies of 75–90%. One application of Energy storage that illustrates the tradeoff between these different aspects of Energy performance is capturing overgeneration (spilled power) for later use during times of peak output from renewables. We quantify the relative energetic benefit of adding different types of Energy storage to a renewable generating facility using [EROI]grid. Even with 30% round-trip efficiency, RHFC storage achieves the same [EROI]grid as batteries when storing overgeneration from wind turbines, because its high ESOIe ratio and the high EROI of wind generation offset the low round-trip efficiency.

  • can we afford storage a dynamic Net Energy Analysis of renewable electricity generation supported by Energy storage
    Energy and Environmental Science, 2014
    Co-Authors: Michael Carbajalesdale, C J Barnhart, Sally M Benson
    Abstract:

    Global wind power and photovoltaic (PV) installed capacities are growing at very high rates (20% per year and 60% per year, respectively). These technologies require large, ‘up-front’ energetic investments. Conceptually, as these industries grow, some proportion of their electrical output is ‘re-invested’ to support manufacture and deployment of new generation capacity. As variable and intermittent, renewable generation capacity increases grid peNetration, electrical Energy storage will become an ever more important load-balancing technology. These storage technologies are currently expensive and Energy intensive to deploy. We explore the impact on Net Energy production when wind and PV must ‘pay’ the energetic cost of storage deployment. We present the Net Energy trajectory of these two industries (wind and PV), disaggregated into eight distinct technologies—wind: on-shore and off-shore; PV: single-crystal (sc-), multi-crystalline (mc-), amorphous (a-) and ribbon silicon (Si), cadmium telluride (CdTe), and copper indium gallium (di)selenide (CIGS). The results show that both on-shore and off-shore wind can support the deployment of a very large amount of storage, over 300 hours of geologic storage in the case of on-shore wind. On the other hand, solar PV, which is already energetically expensive compared to wind power, can only ‘afford’ about 24 hours of storage before the industry operates at an Energy deficit. The Analysis highlights the societal benefits of electricity generation–storage combinations with low energetic costs.

  • Energy balance of the global photovoltaic (PV) industry--is the PV industry a Net electricity producer?
    Environmental Science & Technology, 2013
    Co-Authors: Michael Dale, Sally M Benson
    Abstract:

    A combination of declining costs and policy measures motivated by greenhouse gas (GHG) emissions reduction and Energy security have driven rapid growth in the global installed capacity of solar photovoltaics (PV). This paper develops a number of unique data sets, namely the following: calculation of distribution of global capacity factor for PV deployment; meta-Analysis of Energy consumption in PV system manufacture and deployment; and documentation of reduction in energetic costs of PV system production. These data are used as input into a new Net Energy Analysis of the global PV industry, as opposed to device level Analysis. In addition, the paper introduces a new concept: a model tracking energetic costs of manufacturing and installing PV systems, including balance of system (BOS) components. The model is used to forecast electrical Energy requirements to scale up the PV industry and determine the electricity balance of the global PV industry to 2020. Results suggest that the industry was a Net consumer of electricity as recently as 2010. However, there is a >50% that in 2012 the PV industry is a Net electricity provider and will "pay back" the electrical Energy required for its early growth before 2020. Further reducing energetic costs of PV deployment will enable more rapid growth of the PV industry. There is also great potential to increase the capacity factor of PV deployment. These conclusions have a number of implications for RD designing more efficient and durable systems; and deploying PV systems in locations that will achieve high capacity factors.

Enrica Leccisi - One of the best experts on this subject based on the ideXlab platform.

  • Net Energy Analysis and life cycle Energy assessment of electricity supply in chile present status and future scenarios
    Energy, 2018
    Co-Authors: Marco Raugei, Enrica Leccisi, Vasilis Fthenakis, Rodrigo Escobar Moragas, Yeliz Simsek
    Abstract:

    Abstract Chile is one of the fastest-growing economies in Latin America, with a mainly fossil fuelled electricity demand and a population projected to surpass 20 million by 2035. Chile is undergoing a transition to renewable energies due to ambitious national targets, namely to generate 60% of its electricity from local renewable Energy by 2035, and to achieve a 45%renewable Energy share for all new electric installed capacity. In this work, we present a comprehensive Energy Analysis of the electricity generation technologies currently deployed in Chile. Then, we analyse potential future scenarios, considering a large deployment of RE, mainly PV and wind, to replace coal-fired electricity. The life cycle assessment (LCA) and Net Energy Analysis (NEA) methods are applied in parallel to provide complementary indicators, respectively nr-CED and EROI, and identify weak spots and future opportunities. Special focus is given to the effect on EROI of transporting fossil fuels to Chile. Results show that a large deployment of PV and wind can significantly improve the overall Net Energy performance of electricity generation in Chile, while leading to an electricity supply mix that is >60% less reliant on non-renewable Energy.

  • an approach to prospective consequential life cycle assessment and Net Energy Analysis of distributed electricity generation
    Energy Policy, 2017
    Co-Authors: Chris Jones, Paul Gilbert, Marco Raugei, Sarah Mander, Enrica Leccisi
    Abstract:

    Increasing distributed renewable electricity generation is one of a number of technology pathways available to policy makers to meet environmental and other sustainability goals. Determining the efficacy of such a pathway for a national electricity system implies evaluating whole system change in future scenarios. Life cycle assessment (LCA) and Net Energy Analysis (NEA) are two methodologies suitable for prospective and consequential Analysis of Energy performance and associated impacts. This paper discusses the benefits and limitations of prospective and consequential LCA and NEA Analysis of distributed generation. It concludes that a combined LCA and NEA approach is a valuable tool for decision makers if a number of recommendations are addressed. Static and dynamic temporal allocation are both needed for a fair comparison of distributed renewables with thermal power stations to account for their different impact profiles over time. The trade-offs between comprehensiveness and uncertainty in consequential Analysis should be acknowledged, with system boundary expansion and system simulation models limited to those clearly justified by the research goal. The results of this approach are explorative, rather than for accounting purposes; this interpretive remit, and the assumptions in scenarios and system models on which results are contingent, must be clear to end users.

Michael Carbajalesdale - One of the best experts on this subject based on the ideXlab platform.

  • comparing apples to apples why the Net Energy Analysis community needs to adopt the life cycle Analysis framework
    Energies, 2016
    Co-Authors: David J Murphy, Michael Carbajalesdale, Devin Moeller
    Abstract:

    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.

  • can we afford storage a dynamic Net Energy Analysis of renewable electricity generation supported by Energy storage
    Energy and Environmental Science, 2014
    Co-Authors: Michael Carbajalesdale, C J Barnhart, Sally M Benson
    Abstract:

    Global wind power and photovoltaic (PV) installed capacities are growing at very high rates (20% per year and 60% per year, respectively). These technologies require large, ‘up-front’ energetic investments. Conceptually, as these industries grow, some proportion of their electrical output is ‘re-invested’ to support manufacture and deployment of new generation capacity. As variable and intermittent, renewable generation capacity increases grid peNetration, electrical Energy storage will become an ever more important load-balancing technology. These storage technologies are currently expensive and Energy intensive to deploy. We explore the impact on Net Energy production when wind and PV must ‘pay’ the energetic cost of storage deployment. We present the Net Energy trajectory of these two industries (wind and PV), disaggregated into eight distinct technologies—wind: on-shore and off-shore; PV: single-crystal (sc-), multi-crystalline (mc-), amorphous (a-) and ribbon silicon (Si), cadmium telluride (CdTe), and copper indium gallium (di)selenide (CIGS). The results show that both on-shore and off-shore wind can support the deployment of a very large amount of storage, over 300 hours of geologic storage in the case of on-shore wind. On the other hand, solar PV, which is already energetically expensive compared to wind power, can only ‘afford’ about 24 hours of storage before the industry operates at an Energy deficit. The Analysis highlights the societal benefits of electricity generation–storage combinations with low energetic costs.

Pei-te Chiueh - One of the best experts on this subject based on the ideXlab platform.

  • Life cycle assessment and Net Energy Analysis of offshore wind power systems
    Renewable Energy, 2017
    Co-Authors: Yu-fong Huang, Xing-jia Gan, Pei-te Chiueh
    Abstract:

    Abstract This study attempted to evaluate the environmental impact and Energy benefit of offshore wind power systems using life cycle assessment (LCA) and Net Energy Analysis. The environmental impact of offshore wind power systems is based primarily on ferrous metal, which is used to install the foundations, towers, and nacelles. The impact categories with the greatest relevance were fossil fuels and respiratory inorganics. This study assumed that the life cycle of an offshore wind power system has four stages (production, installation, operation and maintenance, and end-of-life). Two scenarios were examined in this study. The major difference between the scenarios was that Scenario 2 included an offshore substation. The overall environmental impact in Scenario 2 was higher than that in Scenario 1 by approximately 10%. The Net Energy Analysis in this study included the evaluations of cumulative Energy demand (CED), Energy return on investment (EROI), and Energy payback time (EPT). For Scenarios 1 and 2, CED was 0.192 and 0.216 MJ/kWh, EROI was 18.7 and 16.7, and EPT was 12.8 and 14.4 months, respectively. Moreover, when the recycling of waste materials was considered, each scenario produced a 25% lower environmental impact, 30% lower Energy requirement, and 4 months lower EPT.

Morgan Bazilian - One of the best experts on this subject based on the ideXlab platform.

  • life cycle Energy Analysis of building integrated photovoltaic systems bipvs with heat recovery unit
    Renewable & Sustainable Energy Reviews, 2006
    Co-Authors: R. H. Crawford, G. J. Treloar, Robert Fuller, Morgan Bazilian
    Abstract:

    Building integrated photovoltaic (BiPV) systems generate electricity, but also heat, which is typically wasted and also reduces the efficiency of generation. A heat recovery unit can be combined with a BiPV system to take advantage of this waste heat, thus providing cogeneration. Two different photovoltaic (PV) cell types were combined with a heat recovery unit and analysed in terms of their life-cycle Energy consumption to determine the Energy payback period. A Net Energy Analysis of these PV systems has previously been performed, but recent improvements in the data used for this study allow for a more comprehensive assessment of the combined Energy used throughout the entire life-cycle of these systems to be performed. Energy payback periods between 4 and 16.5 years were found, depending on the BiPV system. The Energy embodied in PV systems is significant, emphasised here due to the innovative use of national average input-output (I-O) data to fill gaps in traditional life-cycle inventories, i.e. hybrid Analysis. These findings provide an insight into the Net Energy savings that are possible with a well-designed and managed BiPV system.