Comparative Life Cycle Assessment of a Thai Island's diesel/PV/wind hybrid microgrid

Hybrid microgrid systems are an emerging tool for rural electrification due in part to their purported environmental benefits. This study uses Life Cycle Assessment (LCA) to compare the environmental impacts of a diesel/PV/wind hybrid microgrid on the island of Koh Jig, Thailand with the electrification alternatives of grid extension and home diesel generators. The impact categories evaluated are: acidification potential (kg SO₂ eq), global warming potential (kg CO₂ eq), human toxicity potential (kg 1.4 DCB eq), and abiotic resource depletion potential (kg Sb eq). The results show that the microgrid system has the lowest global warming and abiotic resource depletion potentials of all three electrification scenarios. The use phase of the diesel generator and the extraction of copper are shown to significantly contribute to the microgrid's environmental impacts. The relative environmental impacts of the grid extension scenario are found to be proportional to the distance required for grid extension. Across all categories except acidification potential, the impacts from the home diesel generators are the largest. Sensitivity analyses show that maximizing the renewable energy fraction does not necessarily produce a more environmentally sustainable electrification scenario and that the diesel generator provides versatility to the system by allowing power production to be scaled significantly before more technology is needed to meet demand. While the environmental benefits of the microgrid increase as the installation community becomes more isolated, the choice of electrification scenario requires assigning relative importance to each impact category and considering social and economic factors.     

Constructing low emitting power systems through grid extension in Papua New Guinea (PNG) with rural electrification

The effective rural electrification method varies with economic status and geographical location, and the benefits of decentralized generation differ for each energy system depending on its characteristics. This paper evaluates the most effective generation strategies with rural electrification in an optimized power system of Papua New Guinea (PNG) using a linear programming model. The energy system model developed for the study includes decentralized generation, centralized generation, and grid systems of electricity and gas with consideration for the current energy system and infrastructure. Two methods of rural electrification, decentralized generation and grid extension, are compared with and without the Clean Development Mechanism (CDM). The results of simulations show that extending the power grid that allows economical generation such as coal-fired power and hydropower to supply rural electricity is a more cost effective way for rural electrification. Although grid extension is more capital intensive than decentralized generation, the former reduces the total system cost through reduction of the fossil fuel use. Extending the power grid is also effective at attracting CDM investments, since it makes the power system flexible and provides opportunities to advance low emitting energy such as hydropower.     

A comparative life cycle analysis of hydrogen production via thermochemical water splitting using a Cu-Cl cycle

In this paper, a comparative environmental study is reported of the Cu-Cl water-splitting cycle with various other hydrogen production methods: the sulphur-iodine (S-I) water-splitting cycle, high temperature water electrolysis, conventional steam reforming of natural gas and hydrogen production from renewable resources. The investigation uses life cycle assessment (LCA), which is an analytical tool to identify and quantify environmentally critical phases during the life cycle of a system or a product and/or to evaluate and decrease the overall environmental impact of the system or product. The LCA results for the hydrogen production processes indicate that the thermochemical cycles have lower environmental impacts while steam reforming of natural gas has the highest.     

Comparison of five exergoenvironmental methods applied to candidate energy systems for rural villages in developing countries

This paper tackles the environmental impact assessment of different energy systems for rural communities in developing countries. Ten systems are proposed, modelled, and assessed by five published methods: ReCiPe indicator combined with exergy, exergy wasted, thermo-ecological cost, extended exergy accounting, and extended thermoeconomics. All the methods constitute life cycle assessment (LCA) and mathematically take a similar form, combining an environmental impact assessment with exergetic analysis. Despite the inevitable difference of weighting between methods, most showed clear benefits to using responsibly grown Jatropha oil (rather than diesel) to generate electricity and all showed clear benefits of biogas over solar thermal or fuelwood heat. Analyses of error and sensitivity are presented at the end of the results and discussion section.     

Life cycle assessment of village electrification based on straight jatropha oil in Chhattisgarh,India

A decentralized power generation plant fuelled by straight jatropha oil was implemented in 2006 in Ranidhera, Chhattisgarh, India. The goal of this study was to assess the environmental sustainability of that electrification project in order to provide a scientific basis for policy decisions on electrifying remote villages.A full Life Cycle Assessment (LCA) was conducted on jatropha-based rural electrification and then compared with other electrification approaches such as photovoltaic (PV), grid connection and a diesel-fuelled power generator. In summary, the jatropha-based electrification in Ranidhera reduces greenhouse gas emissions over the full life cycle by a factor of 7 compared to a diesel generator or grid connection. The environmental performance is only slightly improved, mainly due to the high air pollution from pre-heating the jatropha seeds. With additional measures oil extraction and overall efficiency could be further improved. However, environmental benefits can only be achieved if jatropha is cultivated on marginal land and land use competition can be excluded. Under these conditions, jatropha-based electricity generation might be a useful alternative to other renewable electrification options, as the technology is very sturdy and can be maintained even in remote and highly under-developed regions.     

Electrification using solar photovoltaic systems in Nepal

Historically, the rural population of Nepal has been meeting their energy needs from traditional sources like fuel wood and other biomass resources. Only about 44% of the total population has access to grid electricity. Because of country’s rough and mountainous topography, high cost of grid extension, and low and scattered population density, constructing some big power plants (e.g. large hydropower) can not meet the electricity needs of all people, especially those living in rural areas. Distributed generation of electricity, using environment friendly solar photovoltaic (PV) systems, might be one of the reliable alternatives for urban as well as rural electrification. This article begins with a general overview of energy resources in Nepal. Present status and perspectives of solar PV sector have also been discussed. Benefit cost and breakeven analyses of solar PV systems in Nepalese urban areas have been carried out. The breakeven year has been calculated between 2027 and 2036 for PV systems with system life time between 40 and 25 years, respectively. It has been concluded that the solar PV systems are not the economic solutions for grid connected urban areas in Nepal. On the other hand, this article concludes that the rural electrification projects should not be decided on the basis of mere monetary benefits, rather many social aspects should be considered, and in this case, there are not convincing alternatives to solar PV systems for electrification in many rural villages in Nepal.     

Assessment and evaluation of PV based decentralized rural electrification: An overview

The challenges of providing electricity to rural households are manifold. Ever increasing demand–supply gap, crumbling electricity transmission and distribution infrastructure, high cost of delivered electricity are a few of these. Use of renewable energy technologies for meeting basic energy needs of rural communities has been promoted by the Governments world over for many decades. Photovoltaic (PV) technology is one of the first among several renewable energy technologies that was adopted globally as well as in India for meeting basic electricity needs of rural areas that are not connected to the grid. This paper attempts at reviewing and analyzing PV literature pertaining to decentralized rural electrification into two main categories—(1) experiences from rural electrification and technology demonstration programmes covering barriers and challenges in marketing and dissemination; institutional and financing approaches; and productive and economic applications, (2) techno-economic aspects including system design methodologies and approaches; performance evaluation and monitoring; techno-economic comparison of various systems; and environmental implications and life cycle analysis. The paper discusses the emerging trends in its concluding remarks.     

A benchmark for life cycle air emissions and life cycle impact assessment of hydrokinetic energy extraction using life cycle assessment

As the demand for renewable energy increases, it becomes important to critically examine the environmental impacts of renewable energy production. Often, the approach has been trial and error in renewable energy with respect to its impact on the environment. Hydrokinetic Energy Extraction (HEE) has been seen as a potentially “benign” form of renewable hydropower. This paper provides a benchmark for initial measurement of HEE environmental impacts, since negative outcomes have been present with previously assumed “benign” renewable hydropower. A Gorlov system was used to represent a HEE system. Life Cycle Assessment (LCA) was utilized to compare the environmental impacts of HEE with small hydropower, coal, natural gas and nuclear power. Environmental Protection Agency (EPA) criteria air emissions were quantified and compared over the life cycle of the systems. Life cycle air emissions were used in combination with TRACI to compare the systems. The Gorlov system was found to have the lowest life cycle impact with a system lifetime comparison, and did compare closely with small hydropower.     

Multi-objective assessment of rural electrification in remote areas with poverty considerations

Rural electrification with renewable energy technologies (RETs) offers several benefits to remote areas where diesel generation is unsuitable due to fuel supply constraints. Such benefits include environmental and social aspects, which are linked to energy access and poverty reduction in less-favored areas of developing countries. In this case, multi-objective methods are suitable tools for planning in rural areas. In this study, assessment of rural electrification with renewable energy systems is conducted by means of goal programming towards fuel substitution. The approach showed that, in the Non-Interconnected Zones of Colombia, substitution of traditional biomass with an electrification scheme using renewable energy sources provides significant environmental benefits, measured as land use and avoided emissions, as well as higher employment generation rates than diesel generation schemes. Nevertheless, fuel substitution is constrained by the elevated cost of electricity compared to traditional biomass, which raises households’ energy expenditures between twofold to five times higher values. The present approach, yet wide in scope, is still limited for quantifying the impact of energy access improvements on poverty reduction, as well as for the assessment of energy system's technical feasibility.     

Optimised model for community-based hybrid energy system

Hybrid energy system is an excellent solution for electrification of remote rural areas where the grid extension is difficult and not economical. Such system incorporates a combination of one or several renewable energy sources such as solar photovoltaic, wind energy, micro-hydro and may be conventional generators for backup. This paper discusses different system components of hybrid energy system and develops a general model to find an optimal combination of energy components for a typical rural community minimizing the life cycle cost.The developed model will help in sizing hybrid energy system hardware and in selecting the operating options. Micro-hydro-wind systems are found to be the optimal combination for the electrification of the rural villages in Western Ghats (Kerala) India, based on the case study. The optimal operation shows a unit cost of Rs. 6.5/kW h with the selected hybrid energy system with 100% renewable energy contribution eliminating the need for conventional diesel generator.     

Present situation and future prospect of hydropower in China

Hydropower is a clean and renewable energy source. Considering the economic, technical and environmental benefits of hydropower, most countries give priority to its development. China has the richest hydro resources on the planet with a total theoretical hydropower potential of 694 GW. Developing hydropower is of great importance to alleviate the energy crisis and environmental pollution resulting from the rapid economic growth of China in the 21st century. This paper provides a survey of hydropower development in China. Over the last five decades, China’s hydropower has developed quickly. The installed capacity of hydropower is 145.26 GW presently. Some large hydropower plants have been in operation and many are still under construction, including the Three Gorges Project (TGP) and pumped-storage power stations. Small hydropower development accelerates rural electrification of this country.     

Design of environmentally conscious absorption cooling systems via multi-objective optimization and life cycle assessment

In this paper, a systematic method based on mathematical programming is proposed for the design of environmentally conscious absorption cooling systems. The approach presented relies on the development of a multi-objective formulation that simultaneously accounts for the minimization of cost and environmental impact at the design stage. The latter criterion is measured by the Eco-indicator 99 methodology, which follows the principles of life cycle assessment (LCA). The design task is formulated as a bi-criteria nonlinear programming (NLP) problem, the solution of which is defined by a set of Pareto points that represent the optimal trade-off between the economic and environmental concerns considered in the analysis. These Pareto solutions can be obtained via standard techniques for multi-objective optimization. The main advantage of this approach is that it offers a set of alternative options for system design rather than a single solution. From these alternatives, the decision-maker can choose the best one according to his/her preferences and the applicable legislation. The capabilities of the proposed method are illustrated in a case study problem that addresses the design of a typical absorption cooling system.     

Life cycle energy,emissions and cost inventory of power generation technologies in Singapore

Singapore is one of the most industrialised and urbanised economies in South-East Asia. Power supply is an important sub-system in its economy and heavily reliant on imported oil and natural gas. Due to its geographical area, clean/renewable energy sources for power generation are limited. At the same time, in its deregulated electricity market, the adoption of clean/renewable based power generation technology may be hindered by a market pricing mechanism that does not reflect externality costs. For a sustainable power supply, there is a need to change the conventional appraisal techniques. Life cycle assessment (LCA) and life cycle cost analysis (LCCA) are good tools to quantify environmental impacts and economic implications. LCA and LCCA are performed for centralised and distributed power generation technologies in Singapore, namely, oil and Orimulsion-fired steam turbines, natural gas-fired combined cycle plant, solar PV and fuel cell systems. A life cycle energy, emission and cost inventory is established. The results are discussed from the perspectives of fuel security, environmental protection and cost effectiveness of future power generation strategies for Singapore.     

Life cycle assessment study of solar PV systems: An example of a 2.7 kWp distributed solar PV system in Singapore

In life cycle assessment (LCA) of solar PV systems, energy pay back time (EPBT) is the commonly used indicator to justify its primary energy use. However, EPBT is a function of competing energy sources with which electricity from solar PV is compared, and amount of electricity generated from the solar PV system which varies with local irradiation and ambient conditions. Therefore, it is more appropriate to use site-specific EPBT for major decision-making in power generation planning. LCA and life cycle cost analysis are performed for a distributed 2.7 kW_p grid-connected mono-crystalline solar PV system operating in Singapore. This paper presents various EPBT analyses of the solar PV system with reference to a fuel oil-fired steam turbine and their greenhouse gas (GHG) emissions and costs are also compared. The study reveals that GHG emission from electricity generation from the solar PV system is less than one-fourth that from an oil-fired steam turbine plant and one-half that from a gas-fired combined cycle plant. However, the cost of electricity is about five to seven times higher than that from the oil or gas fired power plant. The environmental uncertainties of the solar PV system are also critically reviewed and presented.     

Environmental assessment of small-scale production of wood chips as a fuel for residential heating boilers

This work performs a comparative life cycle assessment (LCA) of two fuels for heating boilers, namely wood chips and oil. The LCA methodology allows comparing the environmental impacts of the two analyzed fuels, thus assessing which is environmentally more advantageous. The study is focused on Mediterranean forests located in the Argençola region (Catalonia, northeastern Spain) by applying forest management practices focused to ensure a sustainable exploitation. The direct use of wood chips as a fuel for boilers simplifies notably the number of processes involved in producing such a fuel. The results presented clearly show the environmental benefits of using small-scale produced wood chips instead of fossil oil by analyzing representative impact categories defined by the CML and EDIP methods, even when considering the changes in the carbon stock in the forests under analysis due to the management approach adopted. A sensitivity analysis has also been conducted to assess the impact of the data with higher uncertainty on the final LCA results.     

Technical,economic and environmental assessment of household biogas digesters for rural communities

This study was carried out in response to the growing interest on household biogas digesters in Latin America, particularly in rural Andean communities. The aim was to compare the fixed dome and plastic tubular digester in terms of biogas production, cost and environmental impact, using the life cycle assessment methodology. Design and operational parameters, construction materials and implementation costs were based on our previous research and literature results for plastic tubular and fixed dome digesters, respectively. According to this analysis, the main advantage of the plastic tubular digester was its ease of implementation and handling, and lower investment cost compared to the fixed dome digester, which appeared to be more environmentally friendly.     

Life cycle assessment of nuclear-based hydrogen production via a copper–chlorine cycle: A neural network approach

A comparative environmental study is reported of nuclear-based hydrogen production using thermochemical water decomposition cycles. The investigation uses a life cycle assessment (LCA) as is an analytical tool to evaluate and reduce the environmental impact of the system or product. The LCA results are presented in terms of acidification potential and global warming potential. Since LCA often utilizes software to model and analyse the system, an artificial neural network (ANN) method can be advantageous. Here, an ANN method is applied to a nuclear-based hydrogen production system. Using an ANN method in this study eliminates the need to use LCA software separately and facilitates the determination of the impacts of altering input parameters of a system (e.g., heat, work, production capacity and plant lifetime). The neural network approach to identify the best system option, consistent with LCA software results, is developed here using ten neurons in the hidden layers.     

Liquid metal activated hydrogen production from waste aluminum for power supply and its life cycle assessment

Hydrogen energy draws increasing concerns as a kind of renewable and clean energy. Liquid metal (LM) activated Al–H₂O reaction is recently emerging as an alternative for real-time hydrogen production. In this study, the energy consumption and environmental impact of this newly emerging method are evaluated via the life cycle assessment (LCA), which indicates that the utilization of waste Al could significantly relieve the energy and environmental issues. In addition, conceptual experiments were conducted to verify the feasibility of hydrogen generation from waste Al, and to disclose the hydrogen generation performances of Al samples in different forms. To balance the cost of LM and reaction efficiency, the optimum mass ratio of LM to Al were explored, and the reusability of LM was demonstrated. Further, a SWOT analysis is adopted to interpret the Strengths and Weakness of such hydrogen production method, and to evaluate the Opportunities and Threats it confronts. Overall, waste Al could provide an energy-saving and environmentally friendly approach to produce hydrogen, which is expected to exploit a new way towards the green hydrogen era.     

Economics, environment, and energy life cycle assessment of automobiles fueled by bio-ethanol blends in China

This study examines the life cycle economics, environment impacts, and energy consumptions of Chinese automobiles fueled by bio-ethanol blends, utilizing life cycle assessment (LCA) techniques, and puts forward C, Env, En, EEE indicators to assess the economics, combined environmental impacts, energy consumption, and the balance of the three, as a means to evaluate whether the energy utilization efficiency and the domestic environment improvement are achieved at the lowest cost possible. A generic gasoline fueled car is used as a baseline case, and the cassava-based E85 fueled FFV in Guangxi is used as a case study. On the life cycle basis, the cost of cassava-based E85 fueled FFV is about 15% higher than that of gasoline fueled car, of which the two key factors are the price of cassava and gasoline, through a cost breakdown analysis. It also has lower life-cycle emissions of CO₂, CO, HC, and PM pollutants, higher NO_X emissions, while about 20% combined environment indicator is lower than that of the gasoline fueled car. And, it is higher in total energy consumption, lower in fossil fuels and petroleum consumptions, and has a better combined energy indicator. Lastly, the EEE indicator of the cassava-based E85 fueled FFV is about 29% less than that of the gasoline fueled car. Hence, E85 fueled FFV is a better vehicle than the gasoline fueled car, taking the balance of all the 3 “E”s, the energy, environmental and economical aspects, into considerations.     

LCAs of a polycrystalline photovoltaic module and a wind turbine

This study compares the environmental impacts of a polycrystalline photovoltaic (PV) module and a wind turbine using the life cycle assessment (LCA) method. This study models landfill disposal and recycling scenarios of the decommissioned PV module and wind turbine, and compares their impacts to those of the other stages in the life cycles. The comparison establishes that the wind turbine has smaller environmental impacts in almost all of the categories assessed. The disposal stage can become a major contributor to the environmental impacts, depending on disposal scenarios. Recycling is an environmentally efficient method, because of its environmental benefits derived from energy savings and resource reclaimed. The end-of-life recycling scenario for a wind turbine has a significant part on the environmental impacts and should not be ignored. However, many factors also influence the degree to which recycling can be beneficial. With the wind turbine recycling scenario, when large quantities of waste are recycled, the potential savings can be quite large, while with the PV module, small quantities of recycled waste mean that the benefits of recycling are not fully reaped.