The Drive towards Development of Hydropower Dominated Energy Source and Its Socio-Economic and Environmental Implications in Ethiopia

Ethiopia is currently driving towards development of hydropower dominated energy source in order to meet the energy demand of its economic sectors. However, the domination of this modern source of energy is expected to be realized if it can substitute the currently dominant modern source of energy, i.e. imported fossil fuel. Besides, hydropower generation is said to have adverse socio-economic and environmental impacts. In cognizant of this, this term paper was prepared: to explore the pros and cons of hydropower generation and to investigate substitutability of this source of energy with fossil fuel. The paper was prepared using extensive review of literatures as well as quantitative regression analysis using time series data having 39 years of observation (from 1971 – 2009). Result of the review of literatures reveals that multiple benefits can be derived from hydropower generation; which may also accompany with various socio-economic and environmental risks. On the other hand, the quantitative regression analysis shows that, even if there is negative association between hydropower generation and the proportion of energy derived from imported fossil fuel, increase in hydropower generation overtime could not significantly reduce the proportion of energy derived from the fossil fuel, yet, due to the country’s huge demand for energy. Hence, it is recommended that huge expansion of hydropower generation is required for hydropower to be the dominant energy source, provided that hydropower can fit to the energy demand of most of the sectors. Moreover, sustainability of development of the economy relying on hydropower dominated energy source is expected to be realized only if the possible risks and costs are appropriately managed. Keywords: Hydropower generation, benefits, risks, fossil fuel, substitutabilit

Master of Science

thesisTarbela Dam is the largest in Pakistan, providing significant fractions of the country's irrigation supply, hydropower generation, and flood control. The operation of Tarbela Dam has been based on maximizing the release of water for irrigation supply. This single objective approach has provided benefits for Pakistan but has not maximized the potential of Tarbela Dam for targeting multiple objectives and considering multiple criteria. In this study, a model was created with the Water Evaluation and Planning (WEAP) System and used to explore the impact of altering the operations of Tarbela Dam in terms of reliability, resilience, and vulnerability (RRV) for the three objectives of irrigation supply, hydropower generation, and flood control. The reservoir performance for the altered operations was compared to the performance following historical operations for both historical and projected future climate and water demand conditions. Simulation results show that a new proposed operations strategy tested under historical climate and water demand conditions would increase RRV by 17%, 67%, and 7%, respectively, for the water supply objective and 34%, 346%, and 22%, respectively, for hydropower generation compared to the historical reservoir performance. The flood control reliability would increase by only 0.3%. For projected future conditions, the proposed operations strategy would increase RRV by 7%, 219%, and 11%, respectively, for water supply and 19%, 136%, and 13% for hydropower generation. For flood control, the reliability would increase by only 2%, while resilience and vulnerability would decrease by 33% and 39%, respectively. The study confirms the potential to improve the ability to provide more reliable and resilient irrigation supply and hydropower generation, although not to reduce vulnerability. The inability to improve flood control performance by altering operations confirms previous studies documenting the need for increased storage capacity. The use of multiple objectives and the RRV criteria is recommended as an approach to guide Tarbela Dam operations

The potential impacts of climate change on hydropower: An assessment of Lujeri micro hydropower scheme, Malawi

Climate change has the potential to affect hydropower generation by either increasing or reducing flows (discharge) and the head. This paper assessed the impacts of climate change on hydropower generation with a focus on Lujeri micro-hydropower scheme in Mulanje district, Malawi. The study analyzed trends in weather time series (air temperature and rainfall) data from 1980 to 2011 in connection to changes in river discharge and their associated impacts on hydropower generation profile. The Mann-Kendall (MK) test was used to detect trends in air temperature, precipitation and discharge. Correlation analysis was also used to uncover the relationship between discharge and precipitation as well as between discharge and temperature. The MK results highlighted significant rising rates of air temperature, precipitation and discharge in some months and decreasing trend in some other months, suggesting significant changes have occurred in the area. The relationship between precipitation and discharge was not significant (p = 0.552), while that between temperature and discharge was significant (p = 0.0001). Therefore, as temperature showed significant increasing trend, it will be associated with decrease in discharge, consequently a decrease in hydropower generation (power is directly proportion to discharge). Hence, proper adaptation measures such as standby alternative sources of energy and storage mechanisms devices should be exploited to ensure electric power is available throughout the year, especially in the hot and dry season when the discharge is usually very low.Key words: Climate change, discharge rate, hydropower, Malawi, precipitation, temperatur

Integrated Reservoir Management under Stochastic Conditions

Economic optimization, Lake levels, Marketed and non-marketed water uses, Non-linear programming, Recreational benefits, Reservoir management, Stochastic inflows, Value of a visitor day, Environmental Economics and Policy, International Development, Land Economics/Use, Production Economics, Productivity Analysis, Public Economics, Resource /Energy Economics and Policy, Risk and Uncertainty,

Assessment of the Impacts of Climate Variability on Hydropower Generation

Climate change poses potential impacts on hydropower generation either positively by increasing or negatively by decreasing river flow. This study assessed the impacts of climate variability on hydropower with a focus on the New Pangani Falls in Tanzania. Rainfall and temperature time series data from 1980-2014 were analyzed in relation to river discharge and associated impacts to hydropower generation. The Man-Kendall test was used to detect trend in both annual and seasonal time series. The results showed a negative trend in annual rainfall with Z= -2.41 at α = 0.05 and the slope Q = -0.964. Seasonal trend analysis showed that the amount of rainfall received during both dry and wet seasons has been decreasing. Positive trend was observed in both average annual maximum and minimum temperature series at α = 0.1 with Z = 1.73 and α = 0.001 with Z= 4.04, respectively and a positive slope for both. Analysis of regime shift at a 5% significant level showed that, rainfall in the New Pangani falls from 1980 to 2014 experienced two decreasing shifts both occurring in the last 15 years of analysis with a percentage of change of more than 10%. This strongly confirms climate variability in the study area. The study shows that hydropower generation depends strongly on the river inflow to the dam (r = 0.98) while changes in temperature do not affect the functioning of the hydropower plant as depicted by the weak linear relationship between temperature, rainfall (r = 0.085) and power generation (r = -0.082). It can be concluded, therefore, that river discharge variability in catchment has an adverse impact on hydropower generation in hydropower plant.&nbsp

Assessment of the life cycle-based environmental impacts of New Zealand electricity : a thesis presented in partial fulfilment of the requirements for the degree of Master in Environmental Management at Massey University, Palmerston North, New Zealand

The life cycle-based environmental impacts of New Zealand electricity arise from the different energy generation systems used to provide electricity to the national grid, and construction, maintenance and operation of the national electricity transmission and distribution system. Due to the high share of hydropower in the New Zealand electricity mix, base load electricity is rainfall dependent and its variable supply is balanced by generation from fossil fuelled power plants, geothermal, and to a lesser extent from wind, biogas and biomass power. This temporal variability of energy sources in the mix changes the Life Cycle Assessment (LCA) results for New Zealand electricity when the environmental impacts are assessed over different time periods. Therefore, this research had two main objectives: to conduct an LCA of electricity generation, and to assess the influence of temporal variation in the electricity mix on LCA results. Using the ecoinvent v 3.1 database and New Zealand-specific data, an LCA model of electricity generation and use was developed for the year 2013. The LCA results, using the CML 2001 – Apr. 2013 impact assessment method, showed that coal and natural gas power plants contributed 10 to 90 % in all impact categories. Electricity transmission and distribution (T&D) infrastructure contributed more than 50 % of the result for Abiotic Depletion Potential (ADP), Terrestrial Ecotoxicity Potential (TETP) and Human Toxicity Potential (HTP) impact categories. The Climate Change Potential (CCP) for 1 kWh of low-voltage electricity was 186 g CO2-eq; for high and medium-voltage electricity, the CCP results were 172 and 176 g CO2-eq per kWh respectively. To investigate the variability in LCA results over different time periods 3, 5 and 10 year moving averages (MAVG) were calculated; as expected, the variability decreased as the time period increased. The analysis showed that the 10 MAVG was associated with the lowest variability in LCA results. However a 10 MAVG will not reflect changes in installed power plant capacity. Therefore for attributional LCA studies of products using electricity over a year-to-year time frame, a representative average of the electricity mix or a 3, 5, or 10 year MAVG can be used as long as there are no changes in installed power plant capacity. This information aids New Zealand´s electricity industries understand environmental impacts associated with transitions to renewable energy technologies and meet greenhouse gas reduction targets

Optimal Allocation of Reservoir Water

The purpose of this paper is to determine the optimal allocation of reservoir water among consumptive and non-consumptive uses. A non-linear mathematical programming model is developed to optimally allocate Lake Tenkiller water among competing uses that maximize the net social benefit. A mass balance is used to determine the level and volume of water in the lake. This paper examines the effect of water management on lake resources when recreational values are and are not included as control variables in the optimization process. Results show that maintaining the lake level to the ‘normal lake level’ of 632 feet during the summer months generates more recreational benefit rather than reducing the lake level by releasing water for hydro power generation.consumptive and non-consumptive use, mass balance equation, non-linear mathematical programming, optimization, recreational uses, water allocation, Resource /Energy Economics and Policy,

Improving the multi-objective evolutionary optimization algorithm for hydropower reservoir operations in the California Oroville-Thermalito complex

This study demonstrates the application of an improved Evolutionary optimization Algorithm (EA), titled Multi-Objective Complex Evolution Global Optimization Method with Principal Component Analysis and Crowding Distance Operator (MOSPD), for the hydropower reservoir operation of the Oroville-Thermalito Complex (OTC) - a crucial head-water resource for the California State Water Project (SWP). In the OTC's water-hydropower joint management study, the nonlinearity of hydropower generation and the reservoir's water elevation-storage relationship are explicitly formulated by polynomial function in order to closely match realistic situations and reduce linearization approximation errors. Comparison among different curve-fitting methods is conducted to understand the impact of the simplification of reservoir topography. In the optimization algorithm development, techniques of crowding distance and principal component analysis are implemented to improve the diversity and convergence of the optimal solutions towards and along the Pareto optimal set in the objective space. A comparative evaluation among the new algorithm MOSPD, the original Multi-Objective Complex Evolution Global Optimization Method (MOCOM), the Multi-Objective Differential Evolution method (MODE), the Multi-Objective Genetic Algorithm (MOGA), the Multi-Objective Simulated Annealing approach (MOSA), and the Multi-Objective Particle Swarm Optimization scheme (MOPSO) is conducted using the benchmark functions. The results show that best the MOSPD algorithm demonstrated the best and most consistent performance when compared with other algorithms on the test problems. The newly developed algorithm (MOSPD) is further applied to the OTC reservoir releasing problem during the snow melting season in 1998 (wet year), 2000 (normal year) and 2001 (dry year), in which the more spreading and converged non-dominated solutions of MOSPD provide decision makers with better operational alternatives for effectively and efficiently managing the OTC reservoirs in response to the different climates, especially drought, which has become more and more severe and frequent in California

Prediction of Hydropower Generation Using Grey Wolf Optimization Adaptive Neuro-Fuzzy Inference System

Hydropower is among the cleanest sources of energy. However, the rate of hydropower generation is profoundly affected by the inflow to the dam reservoirs. In this study, the Grey wolf optimization (GWO) method coupled with an adaptive neuro-fuzzy inference system (ANFIS) to forecast the hydropower generation. For this purpose, the Dez basin average of rainfall was calculated using Thiessen polygons. Twenty input combinations, including the inflow to the dam, the rainfall and the hydropower in the previous months were used, while the output in all the scenarios was one month of hydropower generation. Then, the coupled model was used to forecast the hydropower generation. Results indicated that the method was promising. GWO-ANFIS was capable of predicting the hydropower generation satisfactorily, while the ANFIS failed in nine input-output combinations

A Risky Climate for Southern African Hydro

This in-depth study of the hydrological risks to hydropower dams on the Zambezi River gives an early warning about what Southern Africa could be facing as it contemplates plans for more large hydropower dams in a time of climate change.Currently, 13,000 megawatts of new large-dam hydro is proposed for the Zambezi and its tributaries. The report finds that existing and proposed hydropower dams are not being properly evaluated for the risks from natural hydrological variability (which is extremely high in the Zambezi), much less the risks posed by climate change.Overall, Africa's fourth-largest river will experience worse droughts and more extreme floods. Dams being proposed and built now will be negatively affected, yet energy planning in the basin is not taking serious steps to address these huge hydrological uncertainties. The result could be dams that are uneconomic, disruptive to the energy sector, and possibly even dangerous.The report recommends a series of steps to address the coming storm of hydrological changes, including changes to how dams are planned and operated