Cumulative energy demand in LCA: the energy harvested approach

Frischknecht, Rolf; Wyss, Franziska; Knöpfel, Sybille Büsser; Lützkendorf, Thomas; Balouktsi, Maria

doi:10.1007/s11367-015-0897-4

Cited by 264 publications

(126 citation statements)

References 9 publications

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“…Besides addressing a number of environmental impact categories, such as global warming, ozone depletion, and acidification, LCA also allows the calculation of the total primary energy (PE) harvested from the environment in order to produce a given amount of end product (i.e., electricity in the case of PV), commonly named cumulative energy demand (CED) [19].…”

Section: Life Cycle Assessmentmentioning

confidence: 99%

The Energy and Environmental Performance of Ground-Mounted Photovoltaic Systems—A Timely Update

2016

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Given photovoltaics' (PVs) constant improvements in terms of material usage and energy efficiency, this paper provides a timely update on their life-cycle energy and environmental performance. Single-crystalline Si (sc-Si), multi-crystalline Si (mc-Si), cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) systems are analysed, considering the actual country of production and adapting the input electricity mix accordingly. Energy pay-back time (EPBT) results for fixed-tilt ground mounted installations range from 0.5 years for CdTe PV at high-irradiation (2300 kWh/(m 2¨y r)) to 2.8 years for sc-Si PV at low-irradiation (1000 kWh/(m 2¨y r)), with corresponding quality-adjusted energy return on investment (EROI PE-eq ) values ranging from over 60 to~10. Global warming potential (GWP) per kWh el averages out at~30 g (CO 2 -eq), with lower values (down to~10 g) for CdTe PV at high irradiation, and up to~80 g for Chinese sc-Si PV at low irradiation. In general, results point to CdTe PV as the best performing technology from an environmental life-cycle perspective, also showing a remarkable improvement for current production modules in comparison with previous generations. Finally, we determined that one-axis tracking installations can improve the environmental profile of PV systems by approximately 10% for most impact metrics.

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Section: Life Cycle Assessmentmentioning

confidence: 99%

The Energy and Environmental Performance of Ground-Mounted Photovoltaic Systems—A Timely Update

2016

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“…With combustible fuels in the form of wood, biomass and, most significantly, fossil fuels dominating energy trade, by convention, this type of high-level energy accounting has been recorded in thermal energy units, including BTUs or joules. For the purpose of most LCA studies on the other hand, the primary energy input from a given source is defined as that source's life-cycle CED (Frischknecht et al 2007b(Frischknecht et al , 2015b.…”

Section: Primary Energy Basis For Lca Energy Input Accountingmentioning

confidence: 99%

“…2.2.1). However, several other LCA databases apply the 'energy harvestable' concept to solar PV, for which the renewable energy input is the amount of solar energy needed to produce the electricity generated by the PV module (Frischknecht et al 2015b). From a LCA perspective, the most important consideration is to clearly state the methodology and assumptions for a given study context.…”

Section: Output Energy Form Equivalence In the Context Of Pv Neamentioning

confidence: 99%

An Exploration of Divergence in EPBT and EROI for Solar Photovoltaics

Palmer

Floyd²

2017

Biophys Econ Resour Qual

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Solar photovoltaics (PV) is widely regarded as one of the most promising renewable energy technologies. Net energy analysis (NEA) is a tool to evaluate the energetic performance of all energy supply technologies, including solar PV. Results across studies can appear to diverge sharply, which leads to contestation of NEA's relevance to energy transition feasibility assessment and contributes to ongoing uncertainty in relation to the critical issue of the sustainability of PV. This study explores how PV NEA approaches differ, including in relation to goal definitions, methodologies and boundaries of analysis. It focuses on two principal NEA metrics, energy return on investment (EROI) and energy payback time (EPBT). Here we show that most of the apparent divergence between studies is accounted for by six factors-life-cycle assessment methodology, age of the primary data, PV cell technology, the treatment of intermittency, equivalence of investment and output energy forms, and assumptions about real-world performance. The apparent divergence in findings between studies can often be traced back to different goal definitions. This study reviews the differing approaches and makes the case that NEA is important for assessing the role of PV in future energy systems, but that findings in the form of EROI or EPBT must be considered with specific reference to the details of the particular study context, and the research questions that it seeks to address. NEA findings in a particular context cannot definitively support general statements about EROI or EPBT of PV electricity in all contexts.

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“…A possible way to achieve more consistent results could be to standardize the moisture content [22].…”

Section: Selection Of a Raw Materials Indicator -The Materials Footprintmentioning

confidence: 99%

From cumulated energy demand to cumulated raw material demand: the material footprint as a sum parameter in life cycle assessment

Wiesen

Wirges

2017

Energ Sustain Soc

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Background: Global targets for reducing resource use have been set by organizations such as the International Resource Panel and the European Commission. However, these targets exist only at the macro level, e.g., for individual countries. When conducting an environmental analysis at the micro level, resource use is often neglected as an indicator. No sum parameter indicating all abiotic and biotic raw materials has been considered for life cycle assessment, as yet. In fact, life cycle assessment databases even lack some of the specific input flows required to calculate all abiotic and biotic raw materials. In contrast, the cumulative energy demand, an input-based indicator assessing the use of energy resources, is commonly used, particularly when analyzing energy-intensive product systems. Methods: In view of this, we analyze the environmental relevance of the sum parameter abiotic and biotic raw material demand, which we call the material footprint. First, we show how abiotic and biotic raw material demand can be implemented in the Ecoinvent life cycle assessment database. Employing the adapted database, the material footprint is calculated for 12 individual datasets of chosen materials and crops. The results are compared to those of the cumulated energy demand and four selected impact categories: climate change, ozone depletion, acidification, and terrestrial eutrophication. Results: The material footprint is generally high in the case of extracted metals and other materials where extraction is associated with a large amount of overburden. This fact can lead to different conclusions being drawn compared to common impact categories or the cumulative energy demand. However, the results show that both the range between the impacts of the different materials and the trends can be similar. Conclusions: The material footprint is very easy to apply and calculate. It can be implemented in life cycle assessment databases with a few adaptions. Furthermore, an initial comparison with common impact indicators suggests that the material footprint can be used as an input-based indicator to evaluate the environmental burden, without the uncertainty associated with the assessment of emission-based impacts.

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Cumulative energy demand in LCA: the energy harvested approach

Cited by 264 publications

References 9 publications

The Energy and Environmental Performance of Ground-Mounted Photovoltaic Systems—A Timely Update

The Energy and Environmental Performance of Ground-Mounted Photovoltaic Systems—A Timely Update

An Exploration of Divergence in EPBT and EROI for Solar Photovoltaics

From cumulated energy demand to cumulated raw material demand: the material footprint as a sum parameter in life cycle assessment

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