ESCUELA TÉCNICA SUPERIOR DE INGENIERÍA (ICAI) Degree in Electromechanical Engineering “Study for the implementation of a smart micro-grid in Talavera de la Reina” Author: Francisco Javier de la Pinta Pillin Director: Julio Montes Ponce de León 2 Executive Summary: This project proposes the installation of a micro-grid in the city of Talavera de la Reina. The project will take advantage of local non-manageable resources such as wind, small-hydro or solar PV for electricity production purposes. This system requires a power backing source for moments when power demand or supply require it. In this case, the system will utilise waste products generated in the area of study, transforming them into hydrogen through a plasma gasification process. That hydrogen, that can be stored, will then feed fuel cells, producing the required energy providing a clean, fast and effective response to demand and supply changes. The installation of the micro-grid responds to the broad advantages that distributed generation offers compared to the traditional centralised grid. This configuration will reduce significantly transport losses, as generation will be carried out next to consumption areas. It will as well integrate renewables effectively, eliminating the so-called special regime, that is one of the main contributors to the current increased price of electricity in Spain. In addition, the micro-grid will also provide a cutting-edge solution to EU regulations in the matter of waste management, being able to power-up the micro-grid with waste products in a clean and efficient way. There are many micro-grid examples throughout the world: In the remote island of Ta´U for instance they have achieved energy independence through a combined generation of solar PV power plants and batteries, being able to operate for three days without sunlight. In New York University, a micro-grid was implemented as well, installing a Combined Heat & Power (CHP) plant, providing heat 37 buildings and power to 22 across campus, being able to perform as an island. In addition, it achieves a 68% decrease in CO2, NOX and SO2 emissions. In the case of plasma gasification solutions, the most remarkable example is the MEPL plant in Pune, India. This facility processes 72 tonnes a day of hazardous waste a day, having a rated power of 1,6 MW. It is the biggest facility processing hazardous waste in the world. 6 In this project, the goal is to install a micro-grid able to provide the 55,412 MWh o maximum demand for Talavera´s 83303 inhabitants. Its privileged position allows it to obtain significant shares of solar energy in addition to acceptable levels of wind power and small-hydro nearby. These resources existing in less than 60 km will inform the distributed generation of the micro- grid, adding up to 100,32 MW of solar PV, 55,3 of wind and 9,214 of small hydro of rated power. As it has been said, all of these non-manageable technologies will be backed by a plasma gasification plant combined with fuel cells. There are many waste-to-energy technologies, such as pyrolysis or incineration, but it is plasma gasification the most appropriate one for the micro-grid. It is a state of the art waste-to-energy solution, that takes advantage of the plasma properties, dissociating the organic matter into its fundamental components, eliminating dioxins. The result of the process is a clean hydrogen-rich syngas and a vitrified slag that can be used for construction. For the purpose of feeding the plasma gasification plant, solid urban waste (SUW) and forest and agrarian residues will be collected. SUW, whose collection would be constant throughout the year, provides 26852,09 tons per year. In case of the forest residues, its collection will be seasonal, and will be stored for moments of lack of waste material. It supposes 31298,316 tons per year. Agrarian waste collection is also seasonal, adding up to 5763,12 tons per year. This waste will be introduced in the plasma gasification station, where it will pass through the processes of feed handling, dissociation and metal recovery, gas cooling, filtering and sulphur removal. In the process gas cooling, a Rankine cycle will be implemented, cooling down the output syngas of the reactor and drying up the waste products introduced in it, generating power that will be used to power up the different devices that take part in the process, achieving a higher efficiency of the process. Given the existing waste resources, the plasma gasification plant will be able to produce 911,13 kg of hydrogen per hour. This hydrogen obtained is then introduced in the fuel cells. Fuel cells are electrochemical reactors that in the presence of hydrogen and an oxidant and through an electrolyte, 7 generates power and heat. Considering the hydrogen flow per hour, the number of fuel cells needed ascends to 24. In the project, it has been considered to install a hydrogen-powered Combined Heat and Power (CHP) plant. Combining cycles will boost the efficiency of the process, and given the implementation of hydrogen, its emissions would be zero. Considering that hydrogen CHPs are still in its infancy as just one plant of such characteristics has been installed worldwide, the project has dismissed this option, although it would be a more than accurate choice. For the micro-grid´s operation, fuel cells will generate power only when local non-manageable technologies are not able to meet demand. For times where even with the plasma technology system is not able to meet demand, the micro-grid will import energy from the conventional one. In case renewable production exceeds the requirements of demand, the micro-grid will export energy, obtaining revenues for it. The project has considered all possible scenarios, where the absence of wind power is clearly the most extreme and unfavourable one. In this case, the micro-grid will have a maximum 50% dependency on the conventional grid. As this situation is highly unlikely to happen continuously for a whole day, the technical effectiveness and viability of the micro-grid is then proven. Generation Share in Absence of Wind 0% Conventional Grid 3% 21% Plasma Gasification Solar Energy 50% 26% Small Hydro Wind Power 8 After the technical viability of the micro-grid has been accredited, it is then necessary to acknowledge the economic one. For this purpose, the levelized costs of each technology have been calculated, obtaining the cost of electricity production per technology. Adding up the weighted sum of the costs for all technologies, the cost of the electricity production per kWh produced in the micro-grid would be 9,2588 c€. For the micro-grid to be economically viable, it should be both profitable for the investor and offer a more competitive price for the consumer. For the consumer, the mean electricity price for small consumers in Spain in January 2017 was 13,263 c€/kWh, which means that the consumer will be paying a 30,19% less after the micro- grid´s installation. In case of the investor, all the micro-grid´s investment will be payed-off from the 21st year of operation, and will then make profits for the following four years of operation for the micro- grid, making a total of 114058447 €. All in all, it can be said that the micro-grid´s installation will be both beneficial for consumers and investors, resulting into a remarkably cheaper electricity and attractive investments for investors. Economic viability is proven as well, and in can then be said that the micro-grid is viable in all ways, achieving its different goals and making it an effective and efficient solution for the grid´s current challenges. 9 Resumen: En este proyecto se propone la instalación de una microrred inteligente en Talavera de la Reina. Se aprovecharán los recursos no gestionables en proximidad tales como la energía solar fotovoltaica, la eólica o la pequeña hidráulica con el propósito de generar energía. De esta manera, la red necesitará una fuente de energía gestionable de respaldo para situaciones en que la oferta o la demanda de energía lo requieran. En ese caso, se usarán los residuos generados en el área de estudio para transformarlos en hidrógeno mediante un proceso de gasificación por plasma. El hidrógeno, que es almacenable, alimentará a unas pilas de combustible que producirán la energía requerida, proporcionando una respuesta rápida, limpia y efectiva a los cambios mencionados. La puesta en marcha de la microrred responde a las amplias ventajas que ofrece la generación distribuida en relación a la distribución centralizada tradicional. Esta configuración, por ejemplo, hará disminuir significativamente las pérdidas en el transporte, generando la energía en puntos cercanos a los consumos. También integrará las renovables de manera efectiva, eliminando el denominado régimen especial, que es uno de los factores que más contribuyen al actual alto precio de la electricidad en España. Además, la microrred supone una solución vanguardista en respuesta a las normativas europeas en relación al tratamiento de residuos, siendo capaz de integrarlos para generar energía de manera limpia y eficiente. Hay muchos ejemplos de microrredes por todo el mundo: En la remota isla de Ta´U se hizo energéticamente independiente a partir de una instalación combinada de paneles solares fotovoltaicos y baterías, siendo capaz de operar tres días en ausencia de luz solar. En la New York University también se implementó una microrred, aunque en esta ocasión se trata de un ciclo combinado que proporciona calefacción a 37 edificios del campus y electricidad a 22, siendo capaz de operar en isla. Además, esta planta ha conseguido reducir en un 68% las emisiones de CO2, NOX y SO2.