Electricity sector in India

India is the third largest producer of electricity in the world. During the fiscal year (FY) 2021–22, the total electricity generation in the country was 1,719 TWh, of which 1,484 TWh was generated by utilities. The gross electricity consumption per capita in FY2019 was 1,208 kWh. In FY2015, electric energy consumption in agriculture was recorded as being the highest (17.89%) worldwide. The per capita electricity consumption is low compared to most other countries despite India having a low electricity tariff. The Indian national electric grid has an installed capacity of 416.0 GW as of 31 March 2023. Renewable energy plants, which also include large hydroelectric power plants, constitute 40.7% of the total installed capacity. India's electricity sector is dominated by fossil fuels, in particular coal, which produced about three-quarters of the country's electricity. The government declared its efforts to increase investment in renewable energy. Un

Aspects of the energy transition and their effects on power systems

Laurent Vincent Pagnier

Most European countries are committed to an energy transition which consists in the substitution of conventional CO2 emitting energy sources by new renewable energy sources (RES), in particular wind and solar power. As opposed to conventional energy sources, new RES are distributed, non-dispatchable, fluctuating and inertialess and have negligible marginal costs. In this thesis, we investigate the impact of the energy transition on the electricity sector in Europe. In the first part of this thesis, we investigate the future electricity production and prices in Europe. We develop a dispatch algorithm on an aggregated model of the pan-European power grid with which we study the future European productions. We show that, as the penetration of new RES increases, the transmission grids are more strongly used and that more flexibility is required from conventional generators. The existing infrastructures seem to able to absorb, through increased international power exchanges and usage of the existing pumped-storage hydroelectricity, the variations of new RES productions even for high penetrations. Then we investigate the effects of new RES on electricity prices. We explain why, due to their negligible marginal cost and their lack of dispatchability, they tend to drag electricity prices down and can be considered as a reduction of the load in the electricity pricing. In particular, photovoltaics decreases the volatility of electricity prices. We show that, in most European countries, the day-ahead electricity price is strongly correlated with the residual load, which is obtained by subtracting the non-dispatchable productions, in particular those of the new RES, from the load. From this observation, we build an effective price model based solely on the residual load with which the revenues of different electricity producers are evaluated. The second part of this thesis deals with disturbances in large transmission grids. The substitution of conventional generators by inertialess RES reduces the amount of inertia connected to power systems which might affect their reliability. To examine the propagation of disturbances in large transmission grids, we develop a dynamical model of the continental European transmission grid. We observe that the magnitude of the disturbance following a power loss depends on the fault location. We show that when inertia and primary control are uniformly distributed, the faults exciting the slowest eigenmodes of the network Laplacian are followed by the strongest disturbances. Reducing inertia on those eigenmodes, which are mostly located in the periphery of the grid, affects more its resilience than when the reduction occurs in its center. Finally, we use perturbation theory to derive algorithms for optimal placement of inertia and primary control when some mild inhomogeneities are present in their distributions. We show that,when the vulnerability of the whole grid is taken into account, a uniform distribution of inertia is optimal and the primary control is best placed in the periphery of the grid.

EPFL2019

Vulnerability Assessment of Electric Power Supply under Extreme Weather Conditions

Raphaël Barben

This thesis analyses and models the vulnerability of the electricity power supply under extreme weather conditions. The system under study is the electric supply system that includes major power plants to main load centers. Extreme weather conditions can cause common mode contingencies (CMCs) of overhead power lines, which endanger the security of electricity supply. Planning and operation of transmission systems are subject to N-1 criterion, which requires that all single failures of network elements do not cause a breach of safety limits. This criterion does not guarantee the security of electricity supply at the time of extreme weather conditions. The objective of this research is to identify critical and plausible CMCs, taking into account space-time correlations of extreme weather conditions and possible states of the network. The most vulnerable zones are focused on to determine appropriate countermeasures for reducing vulnerability. In the past, extreme weather events have caused major disruptions. For example, the blackout in New York in 1977 was initiated by three impacts of lightning on high voltage lines. In 1999, hurricane Lothar caused damage to power grids in several countries, leaving hundreds of thousands of people in darkness. These examples demonstrate the vulnerability of power systems to CMCs. Current transmission networks are expected to undergo significant changes in response to developments such as increases in consumption and newly installed capacity. These changes provide an opportunity to strengthen the security of electricity supply in the perspective of extreme weather conditions and even improve the resilience of electric supply systems. The use of the proposed methodology allows reducing the level of vulnerability by reinforcing only few points or change of the topology of the network. Faced with uncertainties about the evolution of networks and plausible extreme weather conditions, a methodology based on scenarios has been selected. The methodology allows the modeler to reproduce the complexity of the problem while still encouraging the learning process. The core of the methodology is founded on a scenario of electric supply systems and a scenario of extreme weather events. The first scenario includes three models: electric, geographic, and reliability. The electric model comprises components of the network compatible with load flow calculations. The geographic model contains a representation of each power line in a geographic information system, and each of these lines is divided into segments that are associated with a reliability model. The reliability model evaluates failure rates related to exposure to extreme weather conditions. Scenarios of extreme weather events are built on data from weather stations or by numerical simulations implemented in a geographic information system. A vulnerability level index is calculated on the basis of probability and severity indices of a priori possible CMCs. These probabilities are evaluated by a simulation of the interaction between the scenario of transmission network and scenario of extreme weather event. They are a subjective and temporal measure of plausibility of CMCs stemming from interactions in space and time of the two systems previously mentioned. The severity index of CMCs is calculated by a contingency analysis that involves the evaluation of security limit violations. A matrix of vulnerability is constructed as a projection of the vulnerability level in two dimensions, including the lines involved in overload and those being overloaded. This matrix allows the identification of the infrastructures involved in the vulnerability and the determination of major zones of vulnerability. Countermeasures are then proposed to reduce the vulnerability of these zones, and these measures may include additions or retirement of lines or other network topology changes. This methodology is applied to the Swiss transmission network in 2018 subject to summer thunderstorms. A reference case from 2006 is compared in terms of vulnerability to a plausible scenario of transmission network 2018. The latter includes an increased consumption of 20%, around 3 GW of pumped-storage power plants, and network changes proposed by the electricity sector plan supported by the Swiss Federal Office of Energy. On another level, two scenarios of extreme weather events were constructed. The first is an intense thunderstorm occurring in the past, where lightning strikes were recorded by a tracking system. The second case stems from a simulation of a thunderstorm event composed of six cells passing over the Swiss territory. The vulnerability of both scenarios of electric supply system impacted by both scenarios of extreme weather events was evaluated. Two major zones of vulnerability were detected both in the reference case 2006 and the plausible scenario 2018. They are in mountainous regions near major centers of production. The network changes between 2006 and 2018 did not decrease the vulnerability. This is due to the installation of large generation capacity and the difficulty of building lines as a result of the topography in these regions. To reduce vulnerability, the addition of a 380 kV overhead line is proposed for the plausible scenario 2018. This line allows draining off the new hydro generation by offering a new route to major consumption centers and drastically reduces the vulnerability of the two zones mentioned. This measure illustrates the methodology's ability to identify areas of vulnerability and propose actions to increase network resilience. One of the major contributions and innovative points of this research is the consideration of the spatiotemporal correlations of extreme weather conditions for the geographical distribution and structural resistance of transmission lines. In the application of the Swiss 2018 scenario of transmission network, the concept of major zones of vulnerability was useful in identifying the weakest zones and in finding a measure capable of increasing network resilience.

EPFL2010

Vulnerability Assessment of Electric Power Supply under Extreme Weather Conditions

Raphaël Barben

EPFL2010

Aspects of the energy transition and their effects on power systems

Laurent Vincent Pagnier

EPFL2019

Aspects of the energy transition and their effects on power systems

Vulnerability Assessment of Electric Power Supply under Extreme Weather Conditions

The facilitation of small hydropower in Switzerland: shaping the institutional framework

Vulnerability Assessment of Electric Power Supply under Extreme Weather Conditions

Aspects of the energy transition and their effects on power systems

The facilitation of small hydropower in Switzerland: shaping the institutional framework