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Abstract This paper reviews the existing bottom-up energy system models applied at island level. The aim of the paper is to answer the following research questions: i) which energy system models are mostly used at island level? ii) Are national scale models also used for island applications? If yes, which type of additional constraints or adaptations are implemented? iii) A classification of these constraints will be provided in the paper. iv) Which are the main challenges of energy system models applied at insular level? The mostly used bottom-up energy system models are EnergyPLAN, unit commitment models and HOMER. Almost 37% of the analysed studies present models specifically designed for insular applications. The remaining part utilizes models originally designed for Country (47%) or micro-grid (16%) level applications. The additional constraints required by insular applications have been identified to be: reliability and robustness of the power grid, water desalination, vehicle to grid, demand response and maritime transport. The results have shown that the identified additional constraints are more frequently implemented by models that are specifically designed for insular applications. In particular, unit commitment models are capable to take directly into account reliability and robustness of the power grid constraints while models such as EnergyPLAN, HOMER and H2RES have to use alternative simplified methods based on the use of indicators to account for them.

To face environmental and energy security issues, planning an energy system with high penetration of renewables is becoming increasingly important. The EPLANopt model couples a multi-objective evolutionary algorithm to EnergyPLAN simulation software to study the future best energy mix. In this study, EPLANopt is applied to the case study of Niederösterreich, an Austrian region, to inspect the best configurations of the energy system at 2050. This model is used to inspect the competition between different renewable energy integration options. Storage systems, power to gas, power to heat or power to mobility are all integration options taken into account to study their competition in presence of electricity excess from renewables. The results show that in order to decarbonize the energy system the increase of the installed power of renewables is not enough to reach the CO2 reduction objective. Integration methods like the already mentioned storage systems, power to gas, power to heat or power to mobility become relevant. In particular the results show a deep energy efficiency refurbishment coupled to power to heat through heat pumps. Power to gas presents a relevant role in the integration of the excess of electricity from renewables. However, at the increase of electric mobility penetration the available excess of electricity is reduced and the deployment of power to gas decreases. International Journal of Sustainable Energy Planning and Management, Vol. 27 (2020): Special Issue from the 5th International Conference on Smart Energy Systems

Abstract The planning of an energy system with high penetration of renewables is increasing in complexity as only an effective implementation can allow the tackling of environmental and energy security issues. The aim of this study is to present the integration of combined cycle gas turbine cycling costs in EPLANopt, a simulation software consisting of EnergyPLAN coupled to a Multi-Objective Evolutionary Algorithm. The model is then applied to the Italian energy system which is characterized by a very high capacity and electricity production from combined cycle gas turbine systems. The proposed approach established a first step in the direction of modelling their role for load modulation accounting for technical constraints and additional costs related to start-up and partial load condition. Results show the importance of considering cycling costs of combined cycle gas turbine system within energy system modelling as the nature of these costs at the increasing of intermittent renewable generation can reach peaks of 33.5 €/MWh. Additionally, the inclusion of CCGT cycling costs in high penetration non programmable renewable energy sources scenarios opens up favorable business models for other load modulation strategies (e.g. electric batteries).

The increase in overall electricity demand in recent years, together with the rapid and significant changes in electricity generation has motivated increased research addressing environmental impacts of current and future electricity generation and supply systems. This article presents a comprehensive life-cycle assessment (LCA) of electricity generation and supply for the Italian current mix and future scenarios, for a wide set of environmental impacts and indicators, addressing intra-year variations, and including average and marginal demand impact perspectives. The generation mix was modelled for a 3-year period (2018–2020) with hourly and country-specific data, for the main generation technologies; and two future scenarios (for 2030) were modelled applying the EPLANopt energy system model. While future scenarios - with larger renewable energy shares - resulted in reduced environmental impacts in most categories, they were associated with burden shifts. In particular, increased shares of solar photovoltaic generation in future scenarios resulted in significant contributions to mineral and metal resource depletion and to land use impacts. The high penetration of renewable energy sources in future scenarios was also associated with important seasonal and hourly variations, demonstrating the importance of addressing intra-year temporal variations. Moreover, complementing an average with a marginal demand perspective provided insight on potential impacts of demand changes. When considering a marginal demand perspective, future scenarios offered no clear benefits in terms of global warming, for example. The research demonstrated the need for comprehensive and detailed environmental impact assessments with fine time resolution, which can assess seasonal and intra-daily variations, and the evaluation of environmental impacts with both average and marginal demand perspectives highlighted the complementary nature of the two in providing insightful results. The approach is fully replicable to other countries and regions - it can improve LCAs of electricity generation and supply and provide robust results to adequately inform decision-making on electricity generation and demand management, toward more sustainable energy systems.

AbstractThis study aims at introducing a new metric to evaluate the production costs of photovoltaic plants that includes the impacts of adding them in the existing energy system. In other words, the levelized cost of electricity concept is enlarged to incorporate the so‐called integration costs. They consider the costs of reinforcing the grid infrastructure to accept the increase of variable renewable sources production and the effects on the operating conditions of the existing fossil fuel power plants. These costs are applied to the utility‐scale photovoltaic plants to analyse how their market parity and profitability would change in the future if a more systematic approach is used to evaluate their production costs. Moreover, a bottom‐up energy system model performing an operational optimization is introduced and coupled with a genetic algorithm to perform the expansion capacity optimization. This model is used to study the effects on the utility‐scale photovoltaic plants' dispatchability if the integration costs are included. The Italian energy system and photovoltaic market projected to the year 2030 are taken as reference. The results of the market parity highlight that its achievement will not be compromised when the integration costs are considered, mainly thanks to the strong decrease of the investment costs expected in the future years. The results of the optimization underline that the future role of photovoltaic plants in the energy mix with low CO2 emissions will not be significantly affected, even when these additional costs are applied as annual costs.