1 Background
Climate change has become a major challenge for our planet over the past decades, primarily driven by human activities that release greenhouse gases, into the atmosphere. These gases trap heat from the sun, leading to global warming and its associated impacts, including more frequent and severe heatwaves, droughts, storms, and rising sea levels. In response to the challenges posed by climate change, countries worldwide are recognising the necessity of transforming how we harvest and utilise energy. Many nations have already devised Renewable Energy (RE) plans with the aim of achieving zero net emissions by 2050 [1].
Cities presently accommodate nearly half of the global population, yet they account for nearly two-thirds of global energy demand and 70% of carbon emissions from the energy sector [2]. It is thus imperative to reduce the \(CO_2\) emissions linked to the powering of urban areas. In line with this, the European Directive 2010/31/EU [3] stipulates that all new buildings constructed from 2030 on wards must be Nearly Zero Energy Buildings, requiring local energy production to match local energy demand.
Among the available RE sources, the most popular RE sources are wind and solar Photovoltaic (PV) systems. Due to the easy accessibility, simpler implementation and noiseless operation, solar PV is the most explored RE source, especially in urban areas. Continuous research investments have resulted in technological advancements that significantly reduce the Levelized Costs of Energy (LCOE) for renewable energy sources [4]. Notably, solar PV has experienced a substantial decline in LCOE, making it one of the most cost-effective electricity generation technologies. Moreover, strategies such as net metering and net billing have been introduced to incentives PV panel adoption, allowing users to remain grid-connected and reap cost benefits. Consequently, urban PV installations are predominantly integrated into the power grid’s distribution network [5].
The integration of solar energy into the electricity grid is particularly critical for achieving sustainable energy goals, especially in urban areas. Europe has emerged as a global leader in installed PV capacity by region, and the growth of solar installations is projected to continue [6]. However, the intermittent nature of solar irradiation due to weather conditions poses operational and security challenges for electricity grids. As solar production and urban energy consumption patterns often diverge, grid overload becomes a concern. Without proper interventions, PV system integration can impact grid reliability, stability, and overall power quality [7].
The heating and mobility sectors are also principal consumers of fossil fuels. It is thus clear that electrification will play decisive role in decarbonisation for the simple reason that electricity is approximately four times more efficient in its usage than fossil energies. This is explained particularly by the intrinsic efficiency of the electric motor and the electric heat pump. One electric kilowatt-hour allows often to replace four kilowatt-hour of fossil energy. It is therefore expected to assist to what is called the “convergence” between the electric, heating and mobility sectors [8]. This will lead to a decrease of the global energy consumption, but will necessitate to dispose more electricity.
As the electrification of heating and mobility sectors gains momentum, the demands placed on the electricity grid are expected to further escalate [9]. Yet, conventional planning of the low-voltage (LV) distribution grids, despite being over-dimensioned to some extent, had not anticipated a scale of electrification that is in line with the current decarbonization goals [7]. The existing electrical grid, originally designed for centralized power generation and unidirectional energy flow, now faces new demands and complexities. These challenges encompass managing the variability in electricity supply resulting from renewable energy integration and addressing the increasing electrification of diverse sectors [10].
To ensure the efficient and sustainable development of the energy system, it is vital for Distribution System Operators (DSOs) to comprehend and test the limits of the electrical grid. By considering the evolving energy landscape and anticipated future changes, this study aims to provide valuable insights into the challenges and opportunities associated with the grid integration of PV systems. More particularly the study will focus on the case of Geneva. With the valuable insights of the Industrial Services of Geneva (SIG), the findings of this research aim to inform the DSOs of the canton, in making informed decisions to enable the reliable and sustainable integration of renewable energy sources into the electric grid.