Share Of Renewable Electricity Generation Research Articles

A holistic analysis of environmental impacts and improvement pathways for the Brazilian electric sector based on long-term planning and life cycle assessment

Brazil presents a high share of renewable electricity generation, mainly due to its favorable hydroelectric potential. However, reports estimate that demand will grow substantially in the long term, requiring a significant diversification of the electricity mix. In this context, this paper analyzes how the environmental impacts of electricity generation tend to change over the horizon 2025–2050 in Brazil and identifies improvement opportunities accounting for environmental and economic factors. To do so, the Open Source Energy Modeling System (OSeMOSYS) is applied to estimate the composition of the electricity mix in 2050. Then, life cycle assessment (LCA) is used to evaluate the associated environmental impacts across ten categories. Lastly, hybrid weighted ɛ-constraint multi-objective optimization (MOO) is employed to evaluate which sources can be used to minimize climate change and the levelized cost of electricity while ensuring that other categories are reasonably restrained. The results indicate that the environmental performance of the Brazilian electricity matrix tends to deteriorate substantially, both when analyzing overall impacts and impacts per kWh. Moreover, the proposed MOO approach suggests that some sources, mainly hydropower, onshore wind, and centralized PV present an all-around economic/environmental performance and might be favorable for expanding the power system.

Global energy transition: The vital role of cobalt in renewable energy

The metallic minerals (Cobalt & Lithium) are critical for the global transition to renewable energy. In this study, we investigate the impact of Cobalt (as a primary) and Lithium (as a secondary mineral) on the share of renewable electricity generation around the world. We test this hypothesis through a panel dataset of 69 countries from 2007 to 2022. The significant results indicate that, first, Cobalt positively impacts the rise of the share of renewable electricity generation. On the contrary, Lithium does not have an impact. Second, Cobalt played a significant role in increasing the share of renewable electricity generation during the global financial crisis and for China, the biggest importer of Cobalt. Third, Cobalt positively impacts renewable electricity generation in low-CO2 and high-CO2 emission countries. Lithium negatively and positively impacts renewable electricity generation for low-CO2 and high-CO2 emissions. Overall, we conclude that Cobalt plays a key role in renewable electricity generation through storage and enhancement of technologies and innovation. The results provide literary and policy implications for researchers and policy makers.

The Nexus between Wholesale Electricity Prices and the Share of Electricity Production from Renewables: An Analysis with and without the Impact of Time of Distress

The continuous integration of renewable energy sources into the EU’s energy mix is reshaping the electricity market dynamics mainly due to the merit order mechanism affecting wholesale electricity prices (WHEP). This article aims to review the wholesale electricity market mechanism, identify the key factors affecting WHEP, and assess the extent of their contributions under different circumstances. Time series datasets, consisting of monthly observations of commodity prices and energy data regarding 25 EU members over the time horizons January 2015–December 2020 (pre-crisis) and January 2015–August 2023 (co-crisis), are used to support the theory, perform the comparison, and verify the validity of our hypotheses with the use of correlation and multiple linear regression analyses. Our empirical results show that in both cases, a 1% increase in the share of renewable electricity generation (RES) from one period to the next is ceteris paribus associated with an average of approx. 0.96% decrease in WHEP for the same period. However, extreme natural gas prices during times of distress significantly increase WHEP due to the merit order mechanism, from an average of 0.19% to 0.55%. This novel approach provides deeper insights into the interconnectedness of WHEP and the energy and environmental commodity prices and RES during changing economic and geopolitical circumstances, primarily highlighting the influencing factor of RES in WHEP developments.

Time, frequency, and quantile-based impacts of disaggregated electricity generation on carbon neutrality: evidence from leading European Union countries

ABSTRACT Due to increasing geopolitical tensions and disruption of gas supplies, European countries have been looking for alternatives for electricity generation (EG). As part of this process, one of the most important goals for long-term sustainability is to ensure carbon neutrality. Therefore, this study analyzes time, frequency, and quantile-based impacts of EG from different electricity generation sources (i.e., renewable, nuclear, and fossil fuels) on carbon neutrality, focusing on four leading European countries. The study applies the wavelet transform coherence (WC), quantile-on-quantile regression (QQ), and Granger causality in quantiles (GQ) to high-frequency daily data between January 2, 2019 and March 10, 2023. Results show that (i) there is a strong time and frequency dependence between EG and CO2 emissions across countries, while results vary by EG sources and countries; (ii) renewable EG dampens CO2 emissions. At higher quantiles, a higher share of renewable EG lowers CO2 emissions in Germany and Spain, while they increase in France; (iii) nuclear EG is beneficial only for the United Kingdom. (iv) Fossil EG increases CO2 emissions in all countries. Excessive fossil EG leads to more CO2 emissions at higher quantiles; (v) the impacts of EG on CO2 emissions have a time-, frequency-, quantile-, country-, and EG source-dependent structure. The outcomes of the study demonstrates that the ideal EG source for countries is mainly renewable EG, while in the case of the United Kingdom, nuclear EG could be an alternative for improving the environment while reducing fossil fuels.

Economic optimization for a dual‐feedstock lignocellulosic‐based sustainable biofuel supply chain considering greenhouse gas emission and soil carbon stock

AbstractEnvironmental factors, including greenhouse gas (GHG) emissions and soil organic carbon (SOC), should be considered when building a sustainable biofuel supply chain. This work developed a three‐step optimization approach integrating a geographical information system‐based mixed‐integer linear programming model to economically optimize the biofuel supply chain on the premise of meeting certain GHG emission criteria. The biomass supply grid cell was considered first, based on a maximum level of GHG emissions, prior to economic optimization. The optimization simultaneously considered dual‐feedstock sourcing, selection between distributed and centralized configurations, and the impact of maintaining SOC balance in agricultural soil on biomass availability. The applicability of the modeling approach was demonstrated through a case study that optimized a dual‐feedstock renewable jet fuel supply chain via a gasification‐Fischer–Tropsch (gasification‐FT) conversion pathway in 2050 under three biomass availability scenarios. The case study results show that the differences in procurement costs and GHG emissions between energy crops and agricultural residues have a large impact on the layout of the supply chain. The supply‐chain configuration tends to be more centralized with large‐scale biorefineries when a supply region has an intensive and centralized distribution of biomass resources. The cost‐supply curves demonstrated the technical potential of biofuels that could be obtained at a certain level of cost. Additionally, sensitivity analysis shows that the GHG emission credit from producing extra electricity during the gasification‐FT process will be significantly reduced with a rising share of renewable electricity generation in the future. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

The Effect of Electric Vehicle Deployment on Renewable Electricity Generation in an Isolated Grid System: The Case Study of Cyprus

Decarbonisation of national economies to mitigate climate change requires transformation of the entire energy system. Investments in renewable energy technologies in the electricity supply system are increasing, but substantial effort is called for in other sectors, such as transport. While European Union member states have submitted their integrated National Energy and Climate Plans, this paper focuses on partial electrification of the transport sector as a measure to reduce carbon dioxide emissions in the isolated grid system of Cyprus in a cost-effective manner. The present work assesses the impact of electric vehicle deployment on the share of renewable electricity generation, electricity costs and carbon dioxide emissions. Quantification of these aspects is provided with an outlook until 2035. A cost-optimisation model (OSeMOSYS) is used that takes into account the electricity supply, road transport, and heating and cooling sectors. Smart charging option is also evaluated as a possibility.

From energy legislation to investment determination: Shaping future electricity markets with different flexibility options

Modern electricity markets are characterized by an increasing share of renewable electricity generation. This growth in the share of renewables yields a highly intermittent generation structure. To efficiently integrate renewable electricity generation into our energy system, flexibility options ranging from storage facilities to demand-side management will play a major role in the low-carbon energy transformation. Keeping up with the growing demand for flexibility, energy law must reduce current investment obstacles for flexibility options and establish a climate for future investments with sufficient incentives for private investors. By taking up perspectives from different disciplines, this paper summarizes current investment barriers, presents an overview of the existing legal energy investment framework of the EU and Germany, and elaborates on challenges of the presented legislation. As we argue, a well-designed energy market legislation will be one of the keys to a successful energy transition. However, policy makers will have to (i) lower investment uncertainty for private investors, (ii) avoid a distortion of energy investment law towards specific flexibility options and technologies, and (iii) reduce the complexity of the current legislation.

Combining Floating Solar Photovoltaic Power Plants and Hydropower Reservoirs: A Virtual Battery of Great Global Potential

Artificial water reservoirs have been created over history for a variety of purposes such as flood control, seasonal water storage for irrigation, fishing, hydropower generation, energy storage, etc. Globally, hydropower represents still the largest share of renewable electricity generation, with over 1170 GW of capacity installed, thereof 328 GW is hydro Run-of-River capacity, and the rest is hydro reservoir based (141 GW of which is hydro pumped storage), controlled to different degrees. These reservoirs cover a surface of approximately 265.7 thousand km2 with the potential to host 4400 GW of floating photovoltaic (PV) power plants at 25% reservoir surface coverage and generate approximately 6270 TWh of electricity. This capacity can be extended to 5700 GW and about 8000 TWh of electricity if all reservoirs (hydropower and for other purposes) are covered at 25%, in both cases generating already more electricity than hydropower from reservoirs at about 2510 TWh. The flexibility of operation of hydro reservoir based power plants and their current connection to grids facilitates a “virtual battery” consisting of supplying the electricity demand with solar energy during peak irradiation hours, while balancing grids with hydropower during low/no irradiation times and providing a zero impact area for PV power plant deployment. The characteristics of the “virtual battery” are investigated and presented in this study. The PV power plants also could prevent approximately 74 billion m3 of water evaporation, further benefiting hydropower production and water conservation, increasing water availability by an estimated 6.3%, adding an estimated 142.5 TWh of production to reservoir-based hydropower plants.

Potential environmental impacts of electric bicycles replacing other transport modes in Wellington, New Zealand

Transport contributed 26% of New Zealand’s direct greenhouse gas (GHG) emissions in 2014 (MFE, 2017). In the same year private car journeys made up 79% of trips nationally and 71% of trips in the capital city Wellington (MOT, 2016b). Electric bicycles (E-bikes) present an opportunity to reduce those emissions. A life cycle assessment approach was used to estimate the environmental impacts of a greater uptake of E-bikes that would displace the use of family size cars powered by petrol or diesel engines. The potential life cycle impacts for the E-bike were found to be favourable compared to the car for most impact categories, including GHG emissions. This was largely due to the approximately 80% share of renewable electricity generation in New Zealand. This electricity mix also meant that the E-bike’s environmental impacts during use were small compared with those related to its production and disposal. The environmental impacts were evaluated for recharging the battery at for four different times of day, representing different average electricity generation mixes. This was found to have very little influence on the environmental performance of the E-bike.The environmental impacts of people switching from other transport modes to E-bikes were calculated for four different user groups in Wellington, New Zealand. These four groups had different transport preferences that were defined with respect to their barriers to cycling: Safe Cyclists, Likely Cyclists, Recreational Cyclists, and Hesitant Cyclists. The groups provided the basis for developing scenarios representing city-wide mode switches from car, bus, train and walking—to use of E-bikes. The Safe Cyclists scenario performed best for 9 of the 15 impact categories. This suggests the desirability of focusing on specific user-groups and their needs in order to change transport behaviours. In particular, in this case it implies a need to prioritise cyclist safety in transport planning (such as providing separate infrastructure for E-bikes).

The spatial distribution of welfare costs of Renewable Portfolio Standards in the United States electricity sector

In the US, renewable energy policy has largely followed a regional approach; 29 states are currently implementing Renewable Portfolio Standards (RPSs) at varying levels of stringency, while the other states have no renewable energy policy. Requiring individual states to achieve given targets is likely to be less efficient and lead to different levels of greenhouse gas (GHG) abatement than a national RPS that achieves the same national share of renewable electricity generation since the latter allows more flexibility in the regional shares based on their relative costs of renewable electricity generation. RPSs are also likely to be less efficient than a national GHG cap and trade (GHG Cap) policy which allow flexibility in achieving GHG abatement through a variety of approaches. We examine the welfare costs and GHG abatement achieved by the existing state RPSs relative to a hypothetical national RPS and a national GHG Cap policy. We undertake this analysis using a dynamic, multi-region, partial-equilibrium, price-endogenous model of the US electricity, agricultural, and transportation sectors, called the Biofuel and Environmental Policy Analysis Model (BEPAM-E). Our results show that a hypothetical national RPS and can induce an equivalent share of renewable-based electricity generation as the state RPSs but at a $61 billion lower welfare cost over the 2007–2030 period. The national RPS would also achieve greater GHG reductions than the state-level RPSs, as it induces a larger decrease in coal generation. We find that the national RPS and national GHG Cap are 55 and 74% more cost-effective in reducing GHG emissions than the state RPSs.

Assessment of probabilistic distributed factors influencing renewable energy supply for hotels using Monte-Carlo methods

This paper investigates the use of renewable energies to supply hotels in island regions. The aim is to evaluate the effect of weather and occupancy fluctuations on the sensitivity of investment criteria. The sensitivity of the chosen energy system is examined using a Monte Carlo simulation considering stochastic weather data, occupancy rates and energy needs. For this purpose, algorithms based on measured data are developed and applied to a case study on the Canary Islands.The results underline that electricity use in hotels is by far the largest contributor to their overall energy cost. For the invested hotel on the Canary Islands, the optimal share of renewable electricity generation is found to be 63%, split into 67% photovoltaic and 33% wind power. Furthermore, a battery is used to balance the differences between day and night. It is found, that the results are sensitive to weather fluctuations as well as economic parameters to about the same degree. The results underline the risk caused by using reference time series for designing energy systems. The Monte Carlo method helps to define the mean of the annuity more precisely and to rate the risk of fluctuating weather and occupancy better.

Role of targeted policies in mainstreaming renewable energy in a resource constrained electricity system: A case study of Karnataka electricity system in India

India is aggressively pursuing its renewable energy capacity expansion goals. Targeted policies such as Feed-in Tariff (FIT), Renewable Purchase Obligation (RPO) and Renewable Energy Certificate (REC) are introduced to stimulate renewable energy capacity expansion as well as generation. Currently, Indian power utilities treat RPO targets as a cost-burden, and therefore there is prevalence of non-compliance. Even other policies, such as FIT and RECs, in their present form, have failed to influence increase in renewable electricity supply. This has lead us to raise an important question whether these policies are adequate for building a cost-effective renewable energy-based low carbon electricity system for India. In this paper, we discuss the impact of above targeted policies in increasing the share of renewable electricity generation in the case of Karnataka State Electricity System. Various scenarios are developed and analysed using mixed-integer programming model to study the impacts. The results suggest that optimally managed FIT and REC schemes can provide opportunities for utilities to benefit from reduced costs. Overall, the above policies are inadequate, and introduction of market-based incentives, which expand the scope of trading in renewable energy certificates, are essential to achieve the desired objectives.

Thermoeconomic Optimization of Solar Thermal Power Plants with Storage in High-penetration Renewable Electricity Markets

Unlike most of renewable energy technologies, solar thermal power plants with integrated thermal energy storage are able to store heat from the sun and thereby supply electricity whenever it is needed to meet the demand. This attribute makes concentrating solar power ideally suited to compensate for fluctuations in other renewable energy sources. In order to analyze this market role, three scenarios were modeled, with low, medium and high penetrations of non-dispatchable renewables (i.e. wind and solar photovoltaics). The demand that cannot be met by these variable sources is met by a solar thermal power plant with heat provided either by a solar field and storage system or a back-up gas burner. For each scenario, the size of the solar field and storage were varied in order to show the trade-off between the levelized generation costs of the system, the annual specific CO2 emissions and the share of renewable electricity generation. The results show that, regardless of the scenario, there exist optimum plant configurations with viable costs whilst simultaneously ensuring a considerable reduction in CO2 emissions. Furthermore, it is shown that the limited flexibility of the power block prevents the system from reaching higher levels of sustainability. Lastly, the results were compared with an equivalent combined cycle power plant, showing that solutions involving solar thermal power can be justified in environmental terms only if large storage units are integrated into the plants.

Assessment of China's renewable energy contribution during the 12th Five Year Plan

In recent years, China has been ambitious in investing and developing renewable energy technologies, aiming to enhance its energy security, mitigate its energy-related CO2 emissions and develop renewable energy industry. The 12th Five Year Plan (2011–2015) has set clear targets on installed capacities of different renewable energy technologies. This study aimed to assess the possible contribution of 12th Five Year Plan for China's future energy system and identify factors that might influence its impacts. First, current status of renewable energy development in China has been reviewed. Then several energy scenarios have been developed in an hourly simulation using an energy system analysis tool EnergyPLAN. It was identified that existing grid bottleneck would greatly reduce the potential contribution of renewable installations in terms of share of renewable electricity generation, share of non-fossil fuels in primary energy and system CO2 emissions. In contrast, improving technical performance of renewable energy technologies and sectoral energy efficiency plays an important role in increasing the share of renewables and promoting China’s energy system transition. Finally, some policy suggestions were drawn to facilitate a better implementation of the renewable energy plan.

Assessing the value of storage in a future energy system with a high share of renewable electricity generation

Increasing the share of intermittent renewable electricity generation will require additional flexibility in the electricity system. While energy storage can provide such flexibility, studies about the economics of power storage often conclude that there is no business case for large-scale storage applications. In this paper, we present a new approach on how to assess the benefits of energy storage. Key improvements have been made in two areas: Firstly, the agent-based market simulation model PowerACE has been enhanced to make use of optimization methods (MILP) for the unit commitment of the agents, enabling us to quantify the economic benefit of flexibility at supply-agent level. Secondly, we have considerably extended the common unit commitment problem (Carrion and Arroyo, IEEE Trans Power Syst 21(3):1371–1378, 2006), so that we can now model the provision of positive and negative balancing power and the dispatch of storage units. We compare the flexibility offered by thermal power plants to that offered by storage units for the four major German electricity generating companies under two different scenarios. The results for 2030 indicate that it would be more profitable to build up to 4,800 MW storage capacity in the German market rather than investing in flexible combined cycle gas turbine plants or hard coal-fired units. The increasingly fluctuating residual load implies that inflexible power plants will be penalized. Using storage units, the power plants of an existing portfolio can be dispatched in a more efficient way, i.e. with less operation in part load and avoiding start-up or shutdown events.

Combining policy instruments for sustainable energy systems: An assessment with the GMM model

An assessment of the impact of an illustrative portfolio of policy instruments that address different sustainability concerns in the global energy system in areas of climate change, air pollution and introduction of renewable-energy resources is conducted. The effects of a policy set containing three instruments, implemented either individually or in combination, were examined. The policy instruments under examination in this work include: Cap-and-Trade policies imposing a CO2 emission reduction target on the global energy system, a renewable portfolio standard that forces a minimum share of renewable electricity generation, and the internalisation of external costs of power generation associated with local pollution. Implementation of these policy instruments significantly changes the structure and environmental performance of the energy sector, and particularly the structure of the electric-generation sector. The positive effects are amplified when the policy instruments are simultaneously applied, illustrating the potential for synergies between these energy-policy domains. The analysis has been conducted with the multi-regional, energy-system Global MARKAL Model (GMM), a “bottom-up” partial-equilibrium model that provides a detailed representation of energy technologies and endogenizes technology learning.