Optimizing renewable-based energy supply options for power generation in Ethiopia.

Ethiopia unveiled homegrown economic reform agenda aimed to achieve a lower-middle status by 2030 and sustain its economic growth to achieve medium-middle and higher-middle status by 2040 and 2050 respectively. In this study, we evaluated the optimal renewable energy mix for power generation and associated investment costs for the country to progressively achieve upper-middle-income countries by 2050. Two economic scenarios: business as usual and Ethiopia's homegrown reform agenda scenario were considered. The study used an Open Source energy Modeling System. The model results suggest: if projected power demand increases as anticipated in the homegrown reform agenda scenario, Ethiopia requires to expand the installed power capacity to 31.22GW, 112.45GW and 334.27GW to cover the current unmet and achieve lower, medium and higher middle-income status by 2030, 2040 and 2050 respectively. The Ethiopian energy mix continues to be dominated by hydropower and starts gradually shifting to solar and wind energy development towards 2050 as a least-cost energy supply option. The results also indicate Ethiopia needs to invest about 70 billion US$ on power plant investments for the period 2021-2030 to achieve the lower-middle-income electricity per capita consumption target by 2030 and staggering cumulative investment in the order of 750 billion US$ from 2031 to 2050 inclusive to achieve upper-middle-income electricity consumption rates by 2050. Ethiopia has enough renewable energy potential to achieve its economic target. Investment and financial sourcing remain a priority challenge. The findings could be useful in supporting decision-making concerning socio-economic development and investment pathways in the country.

An approach to increase the power output of Karnafuli Hydroelectric Power Station: A step to sustainable development in Bangladesh's energy sector.

Renewable energy has become the most prominent source of energy to reduce carbon emissions around the globe. Undoubtedly, hydro energy is very much clean energy among other sources. In Bangladesh, hydro energy is available only in a specific southern area contributing several hundred megawatts to the national grid. This paper devotes to assessing the capacity and practicability of a hydropower plant to boost the power output by implementing the combined cycle hydropower system. The proposed method has been developed by 1) studying the existing plant based on surveyed data, 2) selecting the site for installing the hydrokinetic turbine, 3) designing with consideration of numerous constraints of inter dependability, and 4) creating a prototype model to ensure the practicability. Preliminary results show that a significant amount of additional electric energy can be generated from the plant with higher efficiency.

No COVID-19 climate silver lining in the US power sector.

Recent studies conclude that the global coronavirus (COVID-19) pandemic decreased power sector CO2 emissions globally and in the United States. In this paper, we analyze the statistical significance of CO2 emissions reductions in the U.S. power sector from March through December 2020. We use Gaussian process (GP) regression to assess whether CO2 emissions reductions would have occurred with reasonable probability in the absence of COVID-19 considering uncertainty due to factors unrelated to the pandemic and adjusting for weather, seasonality, and recent emissions trends. We find that monthly CO2 emissions reductions are only statistically significant in April and May 2020 considering hypothesis tests at 5% significance levels. Separately, we consider the potential impact of COVID-19 on coal-fired power plant retirements through 2022. We find that only a small percentage of U.S. coal power plants are at risk of retirement due to a possible COVID-19-related sustained reduction in electricity demand and prices. We observe and anticipate a return to pre-COVID-19 CO2 emissions in the U.S. power sector.

Supply-side options to reduce land requirements of fully renewable electricity in Europe.

Renewable electricity can fully decarbonise the European electricity supply, but large land requirements may cause land-use conflicts. Using a dynamic model that captures renewable fluctuations, I explore the relationship between land requirements and total system cost of different supply-side options in the future. Cost-minimal fully renewable electricity requires some 97,000 km2 (2% of total) land for solar and wind power installations, roughly the size of Portugal, and includes large shares of onshore wind. Replacing onshore wind with offshore wind, utility-scale PV, or rooftop PV reduces land requirements drastically with only small cost penalties. Moving wind power offshore is most cost-effective and reduces land requirements by 50% for a cost penalty of only 5%. Wind power can alternatively be replaced by photovoltaics, leading to a cost penalty of 10% for the same effect. My research shows that fully renewable electricity supply can be designed with very different physical appearances and impacts on landscapes and the population, but at similar cost.

Internalization of External Benefits Brought by Hydropower Development.

Hydropower development brings a very large number of external benefits which are enjoyed by the beneficiaries for free. These external benefits are defined and the beneficiaries are identified. Models to measure the external benefits are established to reflect their dynamic changes at different periods. To improve the benefit sharing mechanism, a model to internalize these external benefits is established to further compensate those adversely affected. The Z hydropower project in China is taken as the example to calculate its external benefits and their internalization. The external benefits enjoyed by beneficiaries in the surrounding and downstream areas gradually increase from 18 million US dollars in 2006 to 114 million US dollars in 2065, and their compensation standards increase from 4 million US dollars in 2006 to 97 million US dollars in 2065. The external benefits enjoyed by beneficiaries in the power receiving areas increase from 125 million US dollars in 2015 to the maximum of 133 million in 2026, and their compensation standards increase from 38 million US dollars in 2015 to the maximum of 133 million US dollars in 2033. Sharing of external benefits can improve the benefit-sharing mechanism, and properly redistribute the external benefits of hydropower development.

An econometric analysis of inter-fuel substitution in energy sector of Pakistan.

Hydroelectricity is playing a significant role in lowering CO2 emissions as it contributes a desirable platform to fulfill the growing energy demand while releasing fewer GHGs in comparison to other fossil fuels. Utilizing the trans-log production model, this study is an endeavor to investigate the potential inter-fuel substitution by estimating the substitution elasticity between pairs of coal, natural gas, petroleum, and hydroelectricity to suggest policy for Pakistan to achieve higher economic growth, environmental sustainability, and increased energy access by its citizens. Over the period 1980-2013, the ridge regression was approved to estimate the model's parameters. The findings show that the output elasticity of hydroelectricity is the highest and all the factor inputs are substitutes; whereas, the elasticity of substitution between coal vs. natural gas is the highest, thus suggesting an increased focus on the coal extraction to switch from the alternative usage of gas. Moreover, encouragement of energy subsidy programs, coupled with taxes and infrastructural developments, can be adapted to redirect technology towards hydroelectricity. Hence, the result that hydroelectricity is substituted for all fuels submit that Pakistan has the potential to switch from petroleum to cleaner energy; therefore, reducing the adverse environmental implications and to retain the ability to fuel its energy sector.

Does combined heat and power mitigate CO2 emissions? A cross-country analysis.

Combined heat and power (CHP), which produces both heat and electricity at the same time, is so efficient that it can reduce energy use and emit less carbon dioxide (CO2) than conventional fossil fuel use. This article attempts to look empirically into the impact of CHP share in total electricity generation on CO2 emissions in a cross-country context. Data from 35 countries during the period 2009-2015 are used. For this purpose, the variable of CO2 emissions is regressed on three variables of constant, gross domestic product, and CHP share using two robust estimators. The results show that the level of CHP share of a country affects the level of its CO2 emissions negatively. That is, CHP leads to less CO2 emissions.

Health benefits and control costs of tightening particulate matter emissions standards for coal power plants - The case of Northeast Brazil.

Exposure to ambient particulate matter (PM) caused an estimated 4.2 million deaths worldwide in 2015. However, PM emission standards for power plants vary widely. To explore if the current levels of these standards are sufficiently stringent in a simple cost-benefit framework, we compared the health benefits (avoided monetized health costs) with the control costs of tightening PM emission standards for coal-fired power plants in Northeast (NE) Brazil, where ambient PM concentrations are below World Health Organization (WHO) guidelines. We considered three Brazilian PM10 (PMx refers to PM with a diameter under x micrometers) emission standards and a stricter U.S. EPA standard for recent power plants. Our integrated methodology simulates hourly electricity grid dispatch from utility-scale power plants, disperses the resulting PM2.5, and estimates selected human health impacts from PM2.5 exposure using the latest integrated exposure-response model. Since the emissions inventories required to model secondary PM are not available in our study area, we modeled only primary PM so our benefit estimates are conservative. We found that tightening existing PM10 emission standards yields health benefits that are over 60 times greater than emissions control costs in all the scenarios we considered. The monetary value of avoided hospital admissions alone is at least four times as large as the corresponding control costs. These results provide strong arguments for considering tightening PM emission standards for coal-fired power plants worldwide, including in regions that meet WHO guidelines and in developing countries.

Siting and sizing of distributed generators based on improved simulated annealing particle swarm optimization.

Distributed power grids generally contain multiple diverse types of distributed generators (DGs). Traditional particle swarm optimization (PSO) and simulated annealing PSO (SA-PSO) algorithms have some deficiencies in site selection and capacity determination of DGs, such as slow convergence speed and easily falling into local trap. In this paper, an improved SA-PSO (ISA-PSO) algorithm is proposed by introducing crossover and mutation operators of genetic algorithm (GA) into SA-PSO, so that the capabilities of the algorithm are well embodied in global searching and local exploration. In addition, diverse types of DGs are made equivalent to four types of nodes in flow calculation by the backward or forward sweep method, and reactive power sharing principles and allocation theory are applied to determine initial reactive power value and execute subsequent correction, thus providing the algorithm a better start to speed up the convergence. Finally, a mathematical model of the minimum economic cost is established for the siting and sizing of DGs under the location and capacity uncertainties of each single DG. Its objective function considers investment and operation cost of DGs, grid loss cost, annual purchase electricity cost, and environmental pollution cost, and the constraints include power flow, bus voltage, conductor current, and DG capacity. Through applications in an IEEE33-node distributed system, it is found that the proposed method can achieve desirable economic efficiency and safer voltage level relative to traditional PSO and SA-PSO algorithms, and is a more effective planning method for the siting and sizing of DGs in distributed power grids.

Biomass pellets for power generation in India: a techno-economic evaluation.

Modern bioenergy is being recognized as an increasingly important low-carbon resource by policy-makers around the world to meet climate policy targets. In India also, there is a clear recognition of the significant role of bioenergy in electricity generation as well as in other applications. In this study, a preliminary attempt has been made to assess the techno-economic feasibility of biomass pellets-based power (BPBP) generation in India. Surplus availability of biomass feedstock from agriculture and forestry/wasteland sector is estimated at 242 million tonnes (Mt) for 2010-11 and is expected to rise to 281 Mt in 2030-31 due to increased crop production and associated waste/residue availability. In terms of related capacity, the potential of BPBP projects is estimated at 35 GW for 2030-31. The associated carbon dioxide mitigation potential resulting from the substitution of coal is estimated at 205 Mt in 2030-31 if the entire biomass surplus is to be diverted for power generation. The levelized cost of electricity is estimated at €0.12 per kWh for BPBP projects as compared to €0.10 per kWh for imported coal based power plants. For states with the lower tariff for biomass power, the break-even price of carbon for BPBP projects is estimated at €18 per tonne. Additionally, BPBP projects will generate employment of more than 5 million person-months in the construction of biomass power plants and over 200,000 full-time employments in the operation of BPBP plants and in the production of biomass pellets.

Environmental and economic analysis of power generation in a thermophilic biogas plant.

This paper investigates the environmental and economic performance of the power production from biogas using Life Cycle Assessment, Life Cycle Costing and Cost Benefit Analysis methodologies. The analysis is based on a commercial thermophilic biogas plant located in Spain where is installed a Combined Heat and Power system that produces electricity that is sold to the grid. Power generation has been assumed as the only function of the biogas system, expanding the system boundaries to include the additional function related to the end-of-life management of the biowastes. Thus environmental burdens from the conventional management of residues were calculated separately and subtracted. The base scenario involves using agri-food waste, sewage sludge and pig/cow manure as substrates. This situation is compared against an alternative scenario where the production of synthetic fertilizer is surrogated by the digestate. The results have shown that the most impacting activities in all impacts categories of power production are primarily attributable to the operation and maintenance of the biogas plant except for water resource depletion and climate change. The avoided emissions associated with the conventional management of pig/cow manure more than offset GHG emissions of the biogas system resulting in a negative impact value of -73.9gCO2eq/kWh in the base case scenario. The normalized results show that local impact categories such as primarily human toxicity, fresh water ecotoxicity and particulate matter are the most significantly affected by the biogas system while global impact categories as climate change and ozone depletion are less severely affected. The operation and maintenance phase is also shown to be the largest contributor after the life cycle cost analysis, followed by the construction and dismantling of the biogas plant and the profitability of the project is primarily related to the income obtained from the management of the biowastes used as substrates.

Energy consumption and energy-saving potential analysis of pollutant abatement systems in a 1000-MW coal-fired power plant.

Pollutant abatement systems are widely applied in the coal-fired power sector, and the energy consumption is considered an important part of the auxiliary power. An energy consumption analysis and assessment model of pollutant abatement systems in a power unit was developed based on the dynamic parameters and technology. The energy consumption of pollutant abatement systems in a 1000-MW coal-fired power unit that meets the ultra-low emission limits and the factors of operating parameters, including unit load and inlet concentration of pollutants, on the operating power were analyzed. The results show that the total power consumption of the pollutant abatement systems accounted for 1.27% of the gross power generation during the monitoring period. The wet flue gas desulfurization (WFGD) system consumed 67% of the rate, whereas the selective catalytic reduction (SCR) and electrostatic precipitator (ESP) systems consumed 8.9% and 24.1%, respectively. The power consumption rate of pollutant abatement systems decreased with the increase of unit load and increased with the increase of the inlet concentration of pollutants. The operation adjustment was also an effective method to increase the energy efficiency. For example, the operation adjustment of slurry circulation pumps could promote the energy-saving operation of the WFGD system. IMPLICATIONS: The application of pollutant abatement technologies increases the internal energy consumption of the power plant, which will lead to an increase of power generation costs. The real-time energy consumption of the different pollutant abatement systems in a typical power unit is analyzed based on the dynamic operating data. Further, the influence of different operating parameters on the operating power of the system and the possible energy-saving potential are analyzed.

Wind farm topology-finding algorithm considering performance, costs, and environmental impacts.

Optimal power in wind farms turns to be a modern problem for investors and decision makers; onshore wind farms are subject to performance and economic and environmental constraints. The aim of this work is to define the best installed capacity (best topology) with maximum performance and profits and consider environmental impacts as well. In this article, we continue the work recently done on wind farm topology-finding algorithm. The proposed resolution technique is based on finding the best topology of the system that maximizes the wind farm performance (availability) under the constraints of costs and capital investments. Global warming potential of wind farm is calculated and taken into account in the results. A case study is done using data and constraints similar to those collected from wind farm constructors, managers, and maintainers. Multi-state systems (MSS), universal generating function (UGF), wind, and load charge functions are applied. An economic study was conducted to assess the wind farm investment. Net present value (NPV) and levelized cost of energy (LCOE) were calculated for best topologies found.

Central Europe: Ethical Overlaps of Environmental and Economic Interests in Coming Years.

Despite the size and thanks to the rich brown coal reserves, the Czech Republic is one of the leading energy producers in Europe, and the 7th biggest exporter of electricity in the world. However, following the climate change mitigation, the novel energy policy that enhances the reduction of coal mining is about to be implemented. A preliminary material flow analysis of the Czech energy sector was carried out. The data obtained confirmed that this government act would result in a dramatic reduction of revenues from electricity sales. Conversely, increased costs would be necessary in order to modernize nuclear power plants and promote the production of renewable energy. In addition, the economic analysis revealed that the act might be prejudicial to economic relations in Central and Western-European countries as some of them are significantly dependent on the electricity imported from the Czech Republic. Disputes between engineers and politicians were highlighted. The aforementioned interrelations were subsequently analyzed and a conclusion was made stating that global interests should have the highest moral priority.

Governing energy while neglecting health - The case of Poland.

The present article discusses Poland's continued reliance on coal power and the consequent impacts on public health. Concrete aspects of the energy infrastructure and political priorities are shown to compromise as compromising public governance and leading to deteriorated health standards among the general population. To make this case, this study juxtaposes the most recent developments in the Polish energy sector with current measures in EU energy policy and reforms in other EU Member States. Special attention is paid to developments in Poland following the political shift in October 2015, when a new government came to power. The ruling conservative party's direct involvement in the management of the mining and utility companies and its strong political ties to miners' unions are particularly discussed. Theoretically, the article relies on the TAPIC framework for governance. The framework rests on five integral principles of good governance: Transparency, Accountability, Participation, Integrity and Capacity; TAPIC allows scholars to study the impact of governance on public health in any policy area. Methodologically, this study relies on secondary sources, including academic publications, national and international reports, and statistical data on a range of energy and health factors in Poland and Europe.

Hydro, wind and solar power as a base for a 100% renewable energy supply for South and Central America.

Power systems for South and Central America based on 100% renewable energy (RE) in the year 2030 were calculated for the first time using an hourly resolved energy model. The region was subdivided into 15 sub-regions. Four different scenarios were considered: three according to different high voltage direct current (HVDC) transmission grid development levels (region, country, area-wide) and one integrated scenario that considers water desalination and industrial gas demand supplied by synthetic natural gas via power-to-gas (PtG). RE is not only able to cover 1813 TWh of estimated electricity demand of the area in 2030 but also able to generate the electricity needed to fulfil 3.9 billion m3 of water desalination and 640 TWhLHV of synthetic natural gas demand. Existing hydro dams can be used as virtual batteries for solar and wind electricity storage, diminishing the role of storage technologies. The results for total levelized cost of electricity (LCOE) are decreased from 62 €/MWh for a highly decentralized to 56 €/MWh for a highly centralized grid scenario (currency value of the year 2015). For the integrated scenario, the levelized cost of gas (LCOG) and the levelized cost of water (LCOW) are 95 €/MWhLHV and 0.91 €/m3, respectively. A reduction of 8% in total cost and 5% in electricity generation was achieved when integrating desalination and power-to-gas into the system.

Carbon dioxide utilization in a microalga-based biorefinery: Efficiency of carbon removal and economic performance under carbon taxation.

Coal-fired power plants are major stationary sources of carbon dioxide and environmental constraints demand technologies for abatement. Although Carbon Capture and Storage is the most mature route, it poses severe economic penalty to power generation. Alternatively, this penalty is potentially reduced by Carbon Capture and Utilization, which converts carbon dioxide to valuable products, monetizing it. This work evaluates a route consisting of carbon dioxide bio-capture by Chlorella pyrenoidosa and use of the resulting biomass as feedstock to a microalgae-based biorefinery; Carbon Capture and Storage route is evaluated as a reference technology. The integrated arrangement comprises: (a) carbon dioxide biocapture in a photobioreactor, (b) oil extraction from part of the produced biomass, (b) gasification of remaining biomass to obtain bio-syngas, and (c) conversion of bio-syngas to methanol. Calculation of capital and operational expenditures are estimated based on mass and energy balances obtained by process simulation for both routes (Carbon Capture and Storage and the biorefinery). Capital expenditure for the biorefinery is higher by a factor of 6.7, while operational expenditure is lower by a factor of 0.45 and revenues occur only for this route, with a ratio revenue/operational expenditure of 1.6. The photobioreactor is responsible for one fifth of the biorefinery capital expenditure, with footprint of about 1000 ha, posing the most significant barrier for technical and economic feasibility of the proposed biorefinery. The Biorefinery and Carbon Capture and Storage routes show carbon dioxide capture efficiency of 73% and 48%, respectively, with capture cost of 139$/t and 304$/t. Additionally, the biorefinery has superior performance in all evaluated metrics of environmental impacts.