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Abstract: This paper investigates the integration of renewable electricity into the UK system in 2020. The purpose is to find the optimal wind generation that can be integrated based on total cost of supply. Using EnergyPLAN model and the Department of Energy and Climate Change (DECC) energy projections as inputs, this paper simulates the total cost of electricity supply with various levels of wind generation considering two systems: a reference and an alternative system. The results show that 80 TWh of wind electricity is most preferable in both systems, saving up to 0.9% of total cost when compared to a conventional system without wind electricity production. The alternative system, with decentralized generation and active demand management, brings relatively more cost saving, and higher wind utilisation, compared to the reference case. The sensitivity analysis with alternative fuel and capital costs again confirms the superiority of the alternative over the reference system. [Copyright &y& Elsevier]

Abstract: Currently, a wide range of strategies is implemented in different countries to increase the share of electricity from renewable energy sources (RES-E). A still controversial discussion is whether quantity-driven (like Tradable Green Certificates (TGCs) based on quotas) or price-driven (like feed-in-tariffs (FIT)) instruments lead to preferable solutions for society. The core objective of this paper is to compare the perspectives of quota-based certificate trading systems for an efficient and effective increase of RES-E with FIT. The major results of this analysis are: (i) The success stories of growth in RES-E in EU member states in recent years has been triggered by FIT implemented in a technology-specific manner at modest costs for European citizens; (ii) At present, TGC systems in most countries applied show a low effectiveness with respect to RES-E deployment of less mature technologies such as solar PV (with improving tendencies in e.g. the UK or Italy with respect to certain technologies); (iii) Compared to short term trading in TGC markets the intrinsic stability of FIT systems appears to be a key element for success; (iv) Hence, currently a well-designed (dynamic) FIT system provides a certain deployment of RES-E in the shortest time and at lowest costs for society. [Copyright &y& Elsevier]

In this paper the driving factors of carbon dioxide emissions from electricity generation in the European Union are examined for the years 2000–2018, separated into three time periods using decomposition analysis, and particularly LMDI-I. Seven driving factors are examined, namely the economic activity effect, the population effect, the electricity intensity effect, the electricity trade effect, the energy intensity effect, the generation structure effect, and the emissions factor effect. The results showed that the main driving factor leading to increased carbon dioxide emissions is the economic activity effect counterbalanced mainly by the contribution of the generation structure effect. Moreover, a decoupling analysis between economic growth and carbon dioxide emissions was carried out aiming to identify the state of each country for each period. In the third examined period (2013–2018) most countries in the EU-27 are in a state of strong decoupling. • Decomposition analysis of CO2 emissions from the power sector in the EU and the UK. • A decoupling analysis between GDP and CO 2 emissions. • Overall reduction in CO 2 emissions from power generation in the period 2000–2018. • Economic activity effect is the main driving factor for CO2 emissions. • Most countries progressed into a state of strong decoupling. [ABSTRACT FROM AUTHOR]

Energy storage can store surplus electricity generation and provide power system flexibility. A Generation Integrated Energy Storage system (GIES) is a class of energy storage that stores energy at some point along with the transformation between the primary energy form and electricity. The investigation of the economic and financial merits of novel energy storage systems and GIES is relevant as these technologies are in their infancy, and there are multiple technological, economic, and financial uncertainties and opportunities. This paper presents and applies a state-of-the-art model to compare the economics and financial merits for GIES (with pumped-heat energy storage) and non-GIES (with a Lithium-ion battery) systems coupled with wind generation in the United Kingdom. The deterministic, risk, and sensitivity analyses show that, for GIES's economics, the key driver is the generator capital cost; for non-GIES, the energy storage capital cost is the most important factor. A Monte Carlo analysis shows that the levelized cost of electricity values for GIES and non-GIES are 0.05 £/kWh - 0.12 £/kWh and 0.07 £/kWh - 0.11 £/kWh, respectively, for a 100 MW wind power generator and 100 MWh energy storage. The internal rate of return values for GIES and non-GIES are uncertain and range between 2%-22% and 5%–14%, respectively. • State-of-the-art cash flow model for generation integrated energy storage (GIES). • Examined the technical, economic, and financial inputs with uncertainties. • First financial and economic comparison of GIES and non-GIES systems. • A UK study with wind energy and pumped thermal energy storage. • Wind farms without energy storage have better economic and financial performance. [ABSTRACT FROM AUTHOR]

Between 2009 and 2017 the share of wind and solar energy sources in the GB electricity generation mix increased from 2.5% to 17%. Due to the variable nature of these renewable sources, large thermal power stations designed for constant base-load operation have been required to operate more flexibly to compensate for fluctuations in renewable generation. This flexible operation results in increased thermal stress and reduced efficiency causing increased operation, maintenance and fuel costs for these assets. In this paper we present the results of what is, to the best of our knowledge, the first empirical study on the impact of renewables generation on startups, ramping and part-loading (collectively, 'cycling') of base-load generators. We develop regression models using half-hourly generation data from 2009 to 2017 that capture the impact of increased renewable penetration while taking into account confounding factors including seasonality and demand. We find that with 2009-levels of renewable generation, cycling in 2017 would have been less severe, with 20% fewer startups. We also present estimates for cycling under National Grid Future Energy Scenarios to 2030 with implications for investment in generation assets. Additionally, the dataset derived in this research is made available and comprises the first open-access dataset on cycling. • A dataset for base-load cycling in the GB power system from 2009 to 2017 is presented. • Base-load cycling is shown to have become stronger during the period 2009–2017. • Regression models for cycling variables are estimated using power system variables. • The models are used to predict cycling under Future Energy Scenarios to 2030. [ABSTRACT FROM AUTHOR]

This paper assesses how operational flexibility and the curtailment of renewable energy are connected using a unit commitment and economic dispatch model that includes operational characteristics of conventional power plants and system constraints. A Great Britain test system is analysed under different scenarios of wind (onshore and offshore) and solar installed capacity, showing that an increase in curtailment is mostly expected as wind deployment increases. This curtailment reaches 17% of the annual available variable renewable electricity generation at high wind and solar installed capacities and is mainly driven by the inertial requirement. The best approach to reducing curtailment is, therefore, to reduce the inertia floor by relaxing Rate of Change of Frequency limits. For the assumed curtailment costs, onshore wind presents a stronger correlation with overall curtailment than offshore wind and solar, albeit influenced by the levels of solar installed capacity. Significant reductions in curtailment can be achieved if wind contributes to system balancing requirements. This emphasizes the importance of ensuring that variable renewables are technically able to contribute to system balancing, wherever feasible, and of improving access to revenue streams that incentivise flexible operation of variable renewable generation. • The inertia floor is the main driver of curtailment in this work. • This curtailment can reach 17% of annual available renewable generation. • Onshore wind has stronger correlation with curtailment than offshore wind or solar. • Curtailment is needed to ensure reserve services when the inertia floor is lowered. • Curtailment can be reduced by 88% if wind contributes to system inertia and reserve. [ABSTRACT FROM AUTHOR]