Low carbon scheduling model for integrated electricity and natural gas systems with power to gas

Abstract

Esta tesis presenta un modelo de planificación del dia siguiente (day ahead) para la operación de sistemas combinados de energía eléctrica y gas natural, centrándose en el papel de Power to Gas (PtG) y su impacto en los costos y emisiones netas de CO2 del sistema. Se modela el sistema eléctrico con in modelo DC de unitcommitment, y se utiliza un modelo hidráulico transitorio para el sistema de gas natural con flujos de gas almacenado en tuberia (linepack) y flujos bidireccionales en las tuberías. El objetivo es medir la influencia de Power to Gas en la consecución de una operación de neutralidad de carbono, aumentando el uso de energía renovable y maximizando la producción de gas natural sintético. Se evalúa el valor de la co-optimizacion diaria entre la gestión de las redes de energía eléctrica y gas natural, y se destaca la importancia de tener en cuenta las limitaciones de las tuberías de gas al analizar sistemas con una alta producción de gas natural y fuentes intermitentes de energía renovable. Los resultados demuestran que la optimización de la combinación de gas y electricidad puede minimizar la restricción de la energía renovable excedente, utilizándola para producir gas sintético. Se proponen tres casos de estudio con diferentes mezclas energéticas, que muestran que Power to Gas permite maximizar el uso de energía renovable y reducir las emisiones de CO2.

In order to reach the carbon peak and begin the transition to a low-carbon economy, it will be necessary to take aggressive action to reduce CO2 emissions and accelerate the deployment of clean energy technologies. It is estimated that for achieving the Paris agreement we will need to capture between 2-10 billion tons of Co2 per year [3]. This will require strong leadership, policy action, and investments in research and development to overcome the barriers to decarbonization. Such actions are replacing coal power with clean alternatives and phasing out fossil fuel subsidies, and ensuring that the full costs (environmental, health, and social) of burning fossil fuels are reflected in their prices, thereby eliminating existing market distortions This thesis presents a day-ahead dispatch model for the operation of integrated power and natural gas systems focusing on the role of the Power to Gas (PtG) and its impact on the cost and net CO2 emissions of the system. The power system is modeled as a DC power flow with unit commitment restrictions and a transient hydraulic gas model for the natural gas system with line-pack and bidirectional flows in the pipelines. The focus is to quantify the power-to-gas role in the objective of carbon neutrality operation through the interaction of power generation and synthetic natural gas (syn-gas) production, by maximizing renewable energy use. The model is used to analyze the value of day-ahead coordination between power and natural gas network operations, and to demonstrate the importance of considering gas pipeline limitations when analyzing power systems with high levels of natural gas production and intermittent renewable energy sources. The results show that natural gas and electricity coupling optimization can minimize the curtailment of excess renewable energy by using it to produce syn-gas, three cases of study are proposed with different energy mixes, demonstrating that power to gas allows the maximization of renewable energy by minimizing the CO2 emission. It was found that, for syn-gas to be competitive, several requirements must be met: its energy source must be the excess of renewable energy, the capacity factor must be at least a certain percentage, and the amount of carbon captured must be economically recognized. Based on the literature review the power to gas stations was characterized. In the study case, power-to-gas technology maximizes the use of the renewable energy potential, for instance in different penetration levels of renewable energy considered in the study case, it was found that in order to produce the optimal amount of syn-gas the sizing of power to gas plants must be related with the expected excess of renewable energy.