Doctoral Recital

List of performers and performances

Master\u27s Recital

List of performers and performances

Junior Recital

List of performers and performances

Modeling hydropower to assess its contribution to flexibility services in the Bolivian power system

peer reviewedBolivia has an important hydroelectric potential that has the potential to be an important part of future energy supply. This potential is due to the topographic characteristics of the country, composed of two large hydrological systems, the Amazon and La Plata basin, with a power of 34,208.50 MW and 5,359.90 MW respectively. Hydropower has been increasing in the Bolivian territory in recent years, with a tripe objective: guarantee energy sovereignty, industrial development and the export of electrical energy. Today, the power system has a 33 % share of hydraulic component, a 61 % share of thermal component, and the rest of other renewable energy sources. Such a composition makes the system vulnerable to hydrological variations that can affect production costs and flexibility of the energy system. Therefore, this study aims to assess the effects of different rainfall years on the ability of hydropower to generate and store electricity. This is done using the hourly power system simulation software Dispa-SET, primarily developed by the European Commission. For the application of the methodology, the Dispa-Set Bolivia model is taken as a basis. For this study the hydroelectric systems are disaggregated by hydro unit, which allows to include the flows of sub-basins in run-of-the-river plants. The information on water inputs for different years is obtained from the Surface Water Balance of Bolivia 2017, which uses the Soil Moisture method (rainfall-runoff) through the software Water Evaluation and Planning (WEAP), for a period from 1980 to 2016. The model optimizes the system under all hydro years, both with a mid-term scheduling approach and a short-term optimal dispatch and unit commitment approach. Modeling has allowed to obtain a broad vision of different scenarios, where main results show that heavy rainfall years affect the electricity production of hydro plants by impacting the flexibility hydropower can provide to the system. This results in changes on the average production costs, which is quantified by differences in terms of electricity production of hydropower plants

Doctoral Recital

Program listing performers and works performed Location: Dr. Arturo Rando-Grillot Recital Hal

Exploring Beethoven: An All Beethoven Gala Concert

Program listing performers and works performe

Filling gaps and disaccumulation of precipitation data for rainfall-runoff model

Precipitation data is one of the most important inputs in rainfall-runoff models. Long records often contain gaps and need to be filled. For the present paper linear regression and multiple linear regression techniques are applied for the estimation of monthly precipitation. For the multiple linear regression technique the tool called HEC4 developed by the U.S. Corps of Engineers is used. The disaccumulation from monthly to daily time scales was done assuming that each station has the same distribution of daily precipitation intensities as the recording station with the highest correlation. The study area considered for this study is part of the Pirai River basin located in Santa Cruz-Bolivia, which is a tributary of the Amazon River. The available data consisted of 33 daily rainfall stations where 8 have more than 25 years of recorded data. These data have been collected by the regional meteorological and hydrological services SENAMHI (Servicio Nacional de Meteorología e Hidrología – Bolivia) and SEARPI (Servicio de Encauzamiento de Aguas y Regularización del río Piraí – Bolivia). The spatial distribution and the range of altitudes of the stations are quite high (334 m.a.s.l. to 1875 m.a.s.l.). The rain gauge density for the study area is 81.97 km2 per station. The gap filling techniques were evaluated based on 32 months extracted from the recorded data. The evaluation was done for 6 days, 3 days and 1 day of disaccumulation period. The multiple linear regression technique applied for the monthly rainfall estimation gives us an important reduction (36%) in the Standard Deviation and Root Mean Squared Error over the linear regression. It is observed that the accuracy of the disaccumulated results decrease when the period of accumulation is smaller. At the daily time scale, the multiple linear and linear regression methods have similar performance.status: publishe

Development of a semi-automated model identification and calibration tool for conceptual modelling of sewer systems

Applications such as real-time control, uncertainty analysis and optimization require an extensive number of model iterations. Full hydrodynamic sewer models do not suffice for these applications due to the excessive computation time. Simplifications are consequently required. A lumped conceptual modelling approach results in a much faster calculation. The process of identifying and calibrating the conceptual model structure could, however, be time consuming. Moreover, many conceptual models lack accuracy, or do not account for backwater effects. To overcome these problems, a modelling methodology was developed which is suited for semi-automatic calibration. The methodology is tested for the sewer system of the city of Geel in the Grote Nete river basin in Belgium, using both synthetic design storm events and long time series of rainfall input. A MATLAB/Simulink® tool was developed to guide the modeller through the step-wise model construction, reducing significantly the time required for the conceptual modelling process.status: publishe

Reference evapotranspiration with limited climatic data in the Bolivian Amazon

Information on the reference evapotranspiration (ET0), or the consumptive water use, is very important and significant for water resources planning and management. The FAO Penman-Monteith (FAO56) equation is considered as the reference methodology for computing ET0. Nevertheless, in some developing countries as in the case of Bolivia, the only available data at some weather stations are the maximum and minimum or mean temperatures; therefore the need for lower data demanding methods is preponderant. The study area considered for this paper is part of the Pirai River basin, which is a tributary of the Amazon River. The available data consisted of 3 weather stations with complete climatic data (CWS). Complete means in this case that daily series are available for nubosity, maximum and minimum temperature, humidity and wind speed, since 1950 to 2000. This data has been collected from the SENAMHI-Santa Cruz I. The data set also consist of another five weather stations with only mean temperature records (TWS) collected from SEARPI II. Maximum and minimum temperature values for these stations could be obtained after extrapolation from the CWS. This extrapolation, however, introduced extra uncertainty, taking into account that the spatial distribution and the range of altitudes of the stations is quite high (373 m.a.s.l. to 1350 m.a.s.l.). The FAO56 method has been applied as a reference method with the objective to calibrate the less data demanding methods to local conditions: Hargreaves-Samani, Thornthwaite and pan evaporation. It has been shown that the Hargreaves- Samani method produces better results than the Thornthwaite method at the CWS stations. It has also been found, as in literature, that the method of Thornthwaite underestimates evapotranspiration in humid areas. Therefore, a local correction factor has been calculated at yearly and monthly basis in order to eliminate the bias, improving the predicting power of the low data demanding formulas under local conditions.status: publishe

Development of a semi-automated model identification and calibration tool for conceptual modelling of sewer systems

Applications such as real-time control, uncertainty analysis and optimization require an extensive number of model iterations. Full hydrodynamic sewer models do not suffice for these applications due to the overlong computation time. Simplifications are consequently required. A lumped conceptual modelling approach results in a much faster calculation. The process of identifying and calibrating the conceptual model structure could, however, be time consuming. Moreover, many conceptual models lack accuracy, or do not account for backwater effects. To overcome these problems, a modelling methodology was developed which is suited for semi-automatic calibration. The methodology is tested for the sewer system of the city of Geel in the Grote Nete river basin in Belgium, using both synthetic design storm events and long time series of rainfall input. A MATLAB/Simulink® tool was developed to guide the modeller through the stepwise model construction, reducing significantly the time required for the conceptual modelling process.status: publishe