Cumulative Primary Energy Research Articles

Life Cycle Assessment as a Major Support Tool within Multi-Criteria Design Process of Single Dwellings Located in Poland

Life cycle assessment is an environmental method which estimates either a process or a building material within the cradle-to-grave cycle. Presently, it is one of a few tools that include all factors which may influence the environment. The authors used this tool to prove effects connected with potential efficient energy levels and a reduction in CO2 emissions within a building’s life cycle. For the purpose of our analyses, several types of single-family building were chosen and they were subjected to analysis in the fixed location of Warsaw. The research scope included a numerical analysis of the buildings concerning the level of embodied energies and the emission of greenhouse gases. The performed analysis proved that, within a 50-year cycle, the difference between the embodied energy from the best and worst building choices can amount to 14.87%, whereas a reduction in embodied carbon emissions can reach 20.65%. Each change in the building’s form and the type of building materials used, regardless of the usable area, influence the environmental impact. Therefore, this paper concludes that LCA, as a management tool, should be used cyclically as part of each phase of the design process. A multi-criteria method for selecting architectural solutions was proposed which considered minimum cumulative primary energy, minimum cumulative carbon emission and minimum cost of constructing a building.

Defining climate change scenario characteristics with a phase space of cumulative primary energy and carbon intensity

Climate change modeling relies on projections of future greenhouse gas emissions and other phenomena leading to changes in planetary radiative forcing. Scenarios of socio-technical development consistent with end-of-century forcing levels are commonly produced by integrated assessment models. However, outlooks for forcing from fossil energy combustion can also be presented and defined in terms of two essential components: total energy use this century and the carbon intensity of that energy. This formulation allows a phase space diagram to succinctly describe a broad range of possible outcomes for carbon emissions from the future energy system. In the following paper, we demonstrate this phase space method with the Representative Concentration Pathways (RCPs) as used in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5).The resulting RCP phase space is applied to map IPCC Working Group III (WGIII) reference case ‘no policy’ scenarios. Once these scenarios are described as coordinates in the phase space, data mining techniques can readily distill their core features. Accordingly, we conduct a k-means cluster analysis to distinguish the shared outlooks of these scenarios for oil, gas and coal resource use. As a whole, the AR5 database depicts a transition toward re-carbonization, where a world without climate policy inevitably leads to an energy supply with increasing carbon intensity. This orientation runs counter to the experienced ‘dynamics as usual’ of gradual decarbonization, suggesting climate change targets outlined in the Paris Accord are more readily achievable than projected to date.

Predicting the quantifiable impacts of ISO 50001 on climate change mitigation

Energy consumption in the industrial and commercial (service) sectors accounts for nearly 40% of global greenhouse gas emissions. Reducing this energy consumption will be critical for countries to achieve their national greenhouse gas reduction commitments. The ISO 50001-Energy management standard provides a continual improvement framework for organizations to reduce their consumption. Several national policies already support ISO 50001; however, there is no transparent, consistent process to estimate the potential impacts of its implementation.This paper presents the ISO 50001 Impacts Methodology, an internationally-developed methodology to calculate these impacts at a national, regional, or global scale suitable for use by policymakers. The recently-formed ISO 50001 Global Impacts Research Network provides a forum for policymakers to refine and encourage use of the methodology.Using this methodology, a scenario with 50% of projected global industrial and service sector energy consumption under ISO 50001 management by 2030 would generate cumulative primary energy savings of approximately 105 EJ, cost savings of nearly US $700 billion (discounted to 2016 net present value), and 6500 million metric tons (Mt) of avoided CO2 emissions. The avoided annual CO2 emissions in 2030 alone are equivalent to removing 210 million passenger vehicles from the road.

Utilization of the horizontal ground heat exchanger in the heating and cooling system of a residential building

AbstractThis paper presents the results of thermodynamic analyses of a system using a horizontal ground heat exchanger to cool a residential building in summer and heat it in the autumn-winter period. The main heating device is a vapour compression heat pump with the ground as the lower heat source. The aim of the analyses is to examine the impact of heat supply to the ground in the summer period, when the building is cooled, on the operation of the heating system equipped with a heat pump in the next heating season, including electricity consumption. The processes occurring in cooling and heating systems have an unsteady nature. The main results of the calculations are among others the time-dependent values of heat fluxes extracted from or transferred to the ground heat exchanger, the fluxes of heat generated by the heat pump and supplied to the heated building by an additional heat source, the parameters in characteristic points of the systems, the temperature distributions in the ground and the driving electricity consumption in the period under analysis. The paper presents results of analysis of cumulative primary energy consumption of the analyzed systems and cumulative emissions of harmful substances.

Environmental benefits of using turkey litter as a fuel instead of a fertiliser

There is an increased interest in the use of poultry litter as fuel by the relevant industries. Hence the environmental impacts of using turkey litter as fuel to generate electricity instead of using litter as fertilizer were systematically analysed for the first time. For this purpose, a systems modelling-based life cycle assessment approach was used, with data obtained directly from the UK turkey industry. Impacts were calculated per 1000 kg turkey live weight produced at the farm gate (functional unit). The avoided burdens method was used to quantify the effects of the alternative litter use. Differences in the environmental impacts between the two litter use scenarios resulted from the combined effect of the following sub-processes: the loss of nitrogen as a crop fertiliser, the transport for collecting litter and distributing the ash as a phosphorus and potassium fertiliser, displacement of electricity generation by a combined cycle gas turbine, specific trace gas emissions from combustion and the loss of soil carbon from the reduced organic matter supply to arable soils. The results showed that there are substantial environmental benefits from using turkey litter as a fuel to generate electricity rather than using it directly as a fertiliser with reductions in burdens of cumulative primary energy demand (14%), eutrophication potential (55%) and acidification potential (70%). The reduction in acidification and eutrophication potentials were mainly associated with reduced ammonia emissions from the storage and land spreading of the litter. Reductions in greenhouse gas emissions were small (3%) because losses of soil carbon as a result of not applying litter to land partially counteracted the benefits of reduced fossil energy use. Small increases in nitrogen oxides, volatile organic carbon, particulate matter below 10 μm aerodynamic diameter and dioxin emissions were found, although only nitrogen oxides were especially linked to combustion. Despite its potential benefits, stringent management, monitoring and regulation of biomass fuelled power production is still needed, given the potential hazards of local high emissions. Although turkey litter was analysed in this study, similar results can be expected for broiler litter use as a fuel, as long as geographical conditions are similar.

The future of energy in Uzbekistan

The Central Asia republic of Uzbekistan is well endowed with energy resources, yet its energy system presents some critical problems in terms of sustainability, security and affordability. Uzbekistan is the most populated country in the region, and therefore population growth, economic development and urbanization are likely to further strain the system in the future. We study some possible pathways for the Uzbek energy sector until 2040. We do so by creating a detailed model of the Uzbek energy system, and analyzing quantitatively the differential effect of determined policies (as compared to Business As Usual ones) in the transformation of the energy demand and supply sides. We find that, even in a scenario of moderate economic growth, energy sector modernization can reduce the cumulative primary energy consumption by 447 Mtoe (10.2 times the primary energy consumption of Uzbekistan in 2010) and CO2 emissions by 1155 Mt (10.5 times the current annual CO2 emissions). To achieve these savings, we estimate the required investment in the power and heat sectors at 2010$33.6 billion, or 1.5% of the country cumulative GDP (gross domestic product) between 2010 and 2040; despite these additional investment needs, we conclude that the affordability of energy to households is preserved or improved.

Uncertainty in Carbon Capture and Storage (CCS) deployment projections: a cross-model comparison exercise

Carbon Capture and Storage (CCS) can be a valuable CO2 mitigation option, but what role CCS will play in the future is uncertain. In this paper we analyze the results of different integrated assessment models (IAMs) taking part in the 27th round of the Energy Modeling Forum (EMF) with respect to the role of CCS in long term mitigation scenarios. Specifically we look into the use of CCS as a function of time, mitigation targets, availability of renewables and its use with different fuels. Furthermore, we explore the possibility to relate model results to general and CCS specific model assumptions. The results show a wide range of cumulative capture in the 2010–2100 period (600–3050 GtCO2), but the fact that no model projects less than 600 GtCO2 indicates that CCS is considered to be important by all these models. Interestingly, CCS storage rates are often projected to be still increasing in the second half of this century. Depending on the scenario, at least six out of eight, up to all models show higher storage rates in 2100 than in 2050. CCS shares in cumulative primary energy use are in most models increasing with the stringency of the target or under conservative availability of renewables. The strong variations of CCS deployment projection rates could not be related to the reported differences in the assumptions of the models by means of a cross-model comparison in this sample.

Environmental life cycle assessment of roof‐integrated flexible amorphous silicon/nanocrystalline silicon solar cell laminate

ABSTRACTThis paper presents an environmental life cycle assessment of a roof‐integrated flexible solar cell laminate with tandem solar cells composed of amorphous silicon/nanocrystalline silicon (a‐Si/nc‐Si). The a‐Si/nc‐Si cells are considered to have 10% conversion efficiency. Their expected service life is 20 years. The production scale considered is 100 MWp per year. A comparison of the a‐Si/nc‐Si photovoltaic (PV) system with the roof‐mounted multicrystalline silicon (multi‐Si) PV system is also presented. For both PV systems, application in the Netherlands with an annual insolation of 1000 kWh/m2 is considered. We found that the overall damage scores of the a‐Si/nc‐Si PV system and the multi‐Si PV system are 0.012 and 0.010 Ecopoints/kWh, respectively. For both PV systems, the impacts due to climate change, human toxicity, particulate matter formation, and fossil resources depletion together contribute to 96% of the overall damage scores. Each of both PV systems has a cumulative primary energy demand of 1.4 MJ/kWh. The cumulative primary energy demand of the a‐Si/nc‐Si PV system has an uncertainty of up to 41%. For the a‐Si/nc‐Si PV system, an energy payback time of 2.3 years is derived. The construction for roof integration, the silicon deposition, and etching are found to be the largest contributors to the primary energy demand of the a‐Si/nc‐Si PV system, whereas encapsulation and the construction for roof integration are the largest contributors to its impact on climate change. Copyright © 2012 John Wiley & Sons, Ltd.

LCA of a biorefinery concept producing bioethanol, bioenergy, and chemicals from switchgrass

The availability of fossil resources is predicted to decrease in the near future: they are a non-renewable source, they cause environmental concerns, and they are subjected to price instability. Utilization of biomass as raw material in a biorefinery is a promising alternative to fossil resources for production of energy carriers and chemicals, as well as for mitigating climate change and enhancing energy security. This paper focuses on a biorefinery concept which produces bioethanol, bioenergy, and biochemicals from switchgrass, a lignocellulosic crop. Results are compared with a fossil reference system producing the same products/services from fossil sources. The biorefinery system is investigated using a Life Cycle Assessment approach, which takes into account all the input and output flows occurring along the production chain. This paper elaborates on methodological key issues like land use change effects and soil N2O emissions, whose influence on final outcomes is weighted in a sensitivity analysis. Since climate change mitigation and energy security are the two most important driving forces for biorefinery development, the assessment has a focus on greenhouse gas (GHG) emissions and cumulative primary energy demand (distinguished into fossil and renewable), but other environmental impact categories (e.g., abiotic depletion, eutrophication, etc.) are assessed as well. The use of switchgrass in a biorefinery offsets GHG emissions and reduces fossil energy demand: GHG emissions are decreased by 79% and about 80% of non-renewable energy is saved. Soil C sequestration is responsible for a large GHG benefit (65 kt CO2-eq/a, for the first 20 years), while switchgrass production is the most important contributor to total GHG emissions of the system. If compared with the fossil reference system, the biorefinery system releases more N2O emissions, while both CO2 and CH4 emissions are reduced. The investigation of the other impact categories revealed that the biorefinery has higher impacts in two categories: acidification and eutrophication. Results are mainly affected by raw material (i.e., switchgrass) production and land use change effects. Steps which mainly influence the production of switchgrass are soil N2O emissions, manufacture of fertilizers (especially those nitrogen-based), processing (i.e., pelletizing and drying), and transport. Even if the biorefinery chain has higher primary energy demand than the fossil reference system, it is mainly based on renewable energy (i.e., the energy content of the feedstock): the provision of biomass with sustainable practices is then a crucial point to ensure a renewable energy supply to biorefineries. This biorefinery system is an effective option for mitigating climate change, reducing dependence on imported fossil fuels, and enhancing cleaner production chains based on local and renewable resources. However, this assessment evidences that determination of the real GHG and energy balance (and all other environmental impacts in general) is complex, and a certain degree of uncertainty is always present in final results. Ranges in final results can be even more widened by applying different combinations of biomass feedstocks, conversion routes, fuels, end-use applications, and methodological assumptions. This study demonstrated that the perennial grass switchgrass enhances carbon sequestration in soils if established on set-aside land, thus, considerably increasing the GHG savings of the system for the first 20 years after crop establishment. Given constraints in land resources and competition with food, feed, and fiber production, high biomass yields are extremely important in achieving high GHG emission savings, although use of chemical fertilizers to enhance plant growth can reduce the savings. Some strategies, aiming at simultaneously maintaining crop yield and reduce N fertilization application through alternative management, can be adopted. However, even if a reduction in GHG emissions is achieved, it should not be disregarded that additional environmental impacts (like acidification and eutrophication) may be caused. This aspect cannot be ignored by policy makers, even if they have climate change mitigation objectives as main goal.

Crop residues as raw materials for biorefinery systems – A LCA case study

Our strong dependence on fossil fuels results from the intensive use and consumption of petroleum derivatives which, combined with diminishing oil resources, causes environmental and political concerns. The utilization of agricultural residues as raw materials in a biorefinery is a promising alternative to fossil resources for production of energy carriers and chemicals, thus mitigating climate change and enhancing energy security. This paper focuses on a biorefinery concept which produces bioethanol, bioenergy and biochemicals from two types of agricultural residues, corn stover and wheat straw. These biorefinery systems are investigated using a Life Cycle Assessment (LCA) approach, which takes into account all the input and output flows occurring along the production chain. This approach can be applied to almost all the other patterns that convert lignocellulosic residues into bioenergy and biochemicals. The analysis elaborates on land use change aspects, i.e. the effects of crop residue removal (like decrease in grain yields, change in soil N 2O emissions and decrease of soil organic carbon). The biorefinery systems are compared with the respective fossil reference systems producing the same amount of products/services from fossils instead of biomass. Since climate change mitigation and energy security are the two most important driving forces for biorefinery development, the assessment focuses on greenhouse gas (GHG) emissions and cumulative primary energy demand, but other environmental categories are evaluated as well. Results show that the use of crop residues in a biorefinery saves GHG emissions and reduces fossil energy demand. For instance, GHG emissions are reduced by about 50% and more than 80% of non-renewable energy is saved. Land use change effects have a strong influence in the final GHG balance (about 50%), and their uncertainty is discussed in a sensitivity analysis. Concerning the investigation of the other impact categories, biorefinery systems have higher eutrophication potential than fossil reference systems. Based on these results, a residues-based biorefinery concept is able to solve two problems at the same time, namely find a use for the abundant lignocellulosic residues and ensure a mitigation effect for most of the environmental concerns related to the utilization of non-renewable energy resources. Therefore, when agricultural residues are used as feedstocks, best management practices and harvest rates need to be carefully established. In fact, rotation, tillage, fertilization management, soil properties and climate can play an important role in the determination of the amount of crop residue that can be removed minimizing soil carbon losses.

Coal-fired oxy-fuel power unit – Process and system analysis

As oxy-fuel power generation is currently on the pre-demonstration stage of development many studies dealing with optimization and simulation aspects are still in progress. This paper is focused on the development of a simulation model of the integrated oxy-fuel system and cumulative energy analysis of an oxy-unit operation in separated national economy. The analyzed oxy-fuel system consists of a steam boiler, steam cycle, air separation unit, as well as a CO 2 purification and compression island. The built model is based on physical relations. It has been developed as a set of modules modelling isolated devices (e.g. combustion chamber or flue gas dehumidifier). Interconnections between these devices can be easily changed, which permits to analyse different oxy-fuel structures and operating parameters. The simulation model has been partially verified on the basis of literature data. Results of oxy fuel energy analysis have been presented for one selected structure and compared with an air combustion power unit, assuming the same steam cycle parameters. For both cases indices of cumulative primary energy consumption have been calculated. The obtained results show that the increase of oxy-fuel primary energy consumption (compared with air-based combustion) can be significantly reduced if by-produced nitrogen will be used for external applications.

A comprehensive environmental assessment of petrochemical solvent production

Organic solvents are used in large quantities in the chemical, metal and electronics industries as well as in many consumer products, such as coatings or paints, and are therefore among the most important chemicals. The petrochemical production of organic solvents is a relevant environmental issue because fossil resources are needed (crude oil and natural gas), synthesis processes are energy-intensive and cause considerable amounts of emissions. So far, comprehensive data on the environmental impact are rather scarce. The aim of this paper is to therefore present a systematical environmental assessment of the main petrochemical solvent production routes using the Life Cycle Assessment (LCA) method. Fifty organic solvents were selected covering the most important representatives from the various chemical groups (e.g., alcohols, esters, ketones). To conduct the LCA, 40 new Life Cycle Inventories (LCI) were established and existing LCI were improved. The petrochemical solvent production was structured into four production routes. In these production routes, the single chemical unit processes (e.g. esterification, carbonylation or hydrogenation) were analyzed in order to determine characteristic environmental impacts. The four solvent production routes including the unit processes and intermediates are presented. Additionally, energy profiles of these production routes are shown using the Cumulative Primary Energy Demand (CED) as an indicator for the environmental impact. The results were cross-checked with the Global Warming Potential and the Eco-indicator 99 method and good correlations were found. Processes that show high environmental impacts are the dehydration of butylene glycol to tetrahydrofuran, the carbonylation of methanol to methyl formate, the hydrogenation of acetone to methyl isobutyl ketone, and the Reppe synthesis of formaldehyd/acetylene to butylene glycol. Based on the energy profiles, ranges of environmental impacts are determined for all unit processes. On the one hand, esterification and alkylation processes cause high CED values because complex ancillaries are needed and hydroformylation and carbonylation processes are energy-intensive. On the other hand, in hydration, hydrogenation, hydrolysis, and oxidation processes, ancillaries with low CED are added to the chemical structure that result in low CED ranges for these unit processes. Dehydrogenation and molecular sieve separation processes seem to be energy efficient and no ancillaries are required. Therefore, these unit processes cause the lowest CED values. Subject of further research in this field should be the environmental analysis of further process steps that include the presented unit processes and a subsequent statistical analysis in order to derive reliable data ranges for all unit processes. Such statistically robust ranges could be used in the approximation of missing life-cycle inventory data of other chemical products and intermediates.

ENVIRONMENTAL SYSTEM ANALYSIS FOR HORTICULTURAL CROP PRODUCTION

ENVIRONMENTAL SYSTEM ANALYSIS FOR HORTICULTURAL CROP PRODUCTION

The potential contribution of nuclear energy to U.S. energy requirements

The relative contribution of nuclear energy to the cumulative total primary energy use in the United States in the period 1975 to 2000 has been estimated for several growth scenarios. If the nuclear capacity grows as recently forecast by ERDA, and if the total primary power use grows by 2%/yr, as recently recommended by the FEA, nuclear energy will contribute 10.8% to our cumulative primary energy use.