•Wind speed spatial resolution highly influences calculated wind power peaks and ramps.•Reduction of wind power generation uncertainties using statistical downscaling.•Publicly available dataset of ...wind power generation hourly time series at NUTS2.
The growing share of electricity production from solar and mainly wind resources constantly increases the stochastic nature of the power system. Modelling the high share of renewable energy sources – and in particular wind power – crucially depends on the adequate representation of the intermittency and characteristics of the wind resource which is related to the accuracy of the approach in converting wind speed data into power values. One of the main factors contributing to the uncertainty in these conversion methods is the selection of the spatial resolution. Although numerical weather prediction models can simulate wind speeds at higher spatial resolution (up to 1×1km) than a reanalysis (generally, ranging from about 25km to 70km), they require high computational resources and massive storage systems: therefore, the most common alternative is to use the reanalysis data. However, local wind features could not be captured by the use of a reanalysis technique and could be translated into misinterpretations of the wind power peaks, ramping capacities, the behaviour of power prices, as well as bidding strategies for the electricity market. This study contributes to the understanding what is captured by different wind speeds spatial resolution datasets, the importance of using high resolution data for the conversion into power and the implications in power system analyses. It is proposed a methodology to increase the spatial resolution from a reanalysis. This study presents an open access renewable generation time series dataset for the EU-28 and neighbouring countries at hourly intervals and at different geographical aggregation levels (country, bidding zone and administrative territorial unit), for a 30year period taking into account the wind generating fleet at the end of 2015.
This paper describes the status quo of the power sector in Burkina Faso, its limitations, and develops a new methodology that through spatial analysis processes with the aim to provide a possible ...pathway for universal electricity access. Following the SE4All initiative approach, it recommends the more extensive use of distributed renewable energy systems to increase access to electricity on an accelerated timeline. Less than 5% of the rural population in Burkina Faso have currently access to electricity and supply is lacking at many social structures such as schools and hospitals. Energy access achievements in Burkina Faso are still very modest. According to the latest SE4All Global Tracking Framework (2015), the access to electricity annual growth rate in Burkina Faso from 2010 to 2012 is 0%. The rural electrification strategy for Burkina Faso is scattered in several electricity sector development policies: there is a need of defining a concrete action plan. Planning and coordination between grid extension and the off-grid electrification programme is essential to reach a long-term sustainable energy model and prevent high avoidable infrastructure investments. This paper goes into details on the methodology and findings of the developed Geographic Information Systems tool. The aim of the dynamic planning tool is to provide support to the national government and development partners to define an alternative electrification plan. Burkina Faso proves to be paradigm case for the methodology as its national policy for electrification is still dominated by grid extension and the government subsidising fossil fuel electricity production. However, the results of our analysis suggest that the current grid extension is becoming inefficient and unsustainable in order to reach the national energy access targets. The results also suggest that Burkina Faso's rural electrification strategy should be driven local renewable resources to power distributed mini-grids. We find that this approach would connect more people to power more quickly, and would reduce fossil fuel use that would otherwise be necessary for grid extension options.
The present paper introduces the results of a spatial-economic analysis that identifies the least cost rural electrification options that can bring the persistent energy poverty to an end in Sub ...Saharan Africa. The rationale behind the analysis is that the applicable energy technologies have gone through fundamental changes and these have profound effects on the competitiveness of the various options.
The least cost distributed generation options are calculated for each geographical location for mini hydro, off grid PV and diesel generators options and it is compared to the electricity grid extension. The methodology presented in this manuscript organises the scarcely available energy-related local and regional geo-information into comprehensible maps. The set of tools presented and the results based on those analyses can support decision and policy makers to plan for the least-cost rural electrification options while also adapting to the most effective way to reduce energy poverty. This can help in the national rural electrification plans by delineating which communities cannot be reached by existing grid without excessive extension costs and gives the alternative distributed generation option.
Wind and solar energy are expected to play a major role in the current decade to help Europe reaching the renewable energy penetration targets fixed by Directive 2009/28/EC. However, it is difficult ...to predict the actual production profiles of wind and solar energy as they depend heavily on variable meteorological features of solar radiation and wind speed. In an ideal system, wind and solar electricity are both injected in a fast reacting grid instantaneously matching supply and demand. In such a system wind and solar electricity production profiles should complement each other as much as possible in order to minimise the need of storage and additional capacity. In the present paper the complementarity of wind and solar resources is assessed for a test year in Italy.
To achieve this goal we employ data at high spatial and temporal resolution data for both solar radiation and wind speed in Italy obtained from running two state of the art models (PVGIS and MINNI). Hourly profiles for solar and wind energy produced are compared in each 4 × 4 km2 grid cell in Italy for 2005, and hourly, daily and monthly correlation coefficients are computed in order to assess the local complementarity of the two resources. A Monte Carlo approach is also developed to estimate how large-scale wind and solar energy productions could be potentially involved to complement each other in a scenario with up to 100 production sites across Italy. The results show how local complementarity can be very interesting with monthly correlation coefficients reaching values lower than −0.8 in several areas. Large-scale complementarity is also relevant with nation-wide monthly correlation coefficients showing values between −0.65 and −0.6. These model results indicate that in this sample year of 2005, wind and solar energy potential production have shown complementary time behaviour complementary, favourably supporting their integration in the energy system.
•A strong complementarity between wind and solar electricity is an advantage for renewable sources exploitation.•Validated models of solar radiation and wind are employed to assess complementarity of wind and solar resources in Italy.•A Monte Carlo approach allows to extend the resource complementarity evaluation in case of multi-site generation.•A robust evaluation of the complementarity between wind and solar resources in a sample year is provided.•Results can support a proper dimensioning of renewable energy generation systems.
Three rural electrification options are analysed showing the cost optimal conditions for a sustainable energy development applying renewable energy sources in Africa. A spatial electricity cost model ...has been designed to point out whether diesel generators, photovoltaic systems or extension of the grid are the least-cost option in off-grid areas. The resulting mapping application offers support to decide in which regions the communities could be electrified either within the grid or in an isolated mini-grid. Donor programs and National Rural Electrification Agencies (or equivalent governmental departments) could use this type of delineation for their program boundaries and then could use the local optimization tools adapted to the prevailing parameters.
Seawater desalination is already a largely adopted option to cope with the scarcity of natural water resources, but the increasing concerns about water availability in the future make it even more ...attractive. Because desalination is a highly energy-demanding process, its coupling with renewable energy sources is an essential step for the sustainable production of desalinated water at large scales. In this work we analyze the potential to deploy large-scale seawater desalination using reverse osmosis (RO) under the hypothesis that all the required energy is provided by photovoltaic (PV) production. A simulation over the extended Mediterranean area shows that securing desalinated water for up to about 200 million people in the region is technically possible using PV only, and the benefits of energy storage in batteries and/or water reservoirs are usually higher than its costs. This suggests that water management policies could consider desalination more broadly and encourage PV-based RO, as a possible win-win and cost-effective strategy to improve water and energy resources security.
Following the successful Feed-in Tariffs (FiTs) system worldwide, few countries have implemented FiTs explicitly tailored for off-grid or mini-grid systems. This study takes an integrated approach to ...examine the feasibility of an off-grid Feed-in Tariff (off-FiT) for existing and new remote mini-grids in Tanzania, using a combination of geographical analysis, technical, economic and institutional assessments. Based on detailed modelling of two community off-grid cases, (i) PV-diesel and (ii) mini-hydro, we identify least-cost rural electrification options that make solar and mini-hydro energy competitive with diesel generators and potential effect of the support scheme on rural electrification plans. In the first case, we illustrate where the off-FiT complements diesel generation of an existing mini-grid (PV-diesel). In the second case (mini-hydro), we illustrate conditions where the off-FiT policy brings mini-hydro generation to non-electrified communities and sells renewable electricity directly to new customers.
Currently, Tanzania has Standardized Power Purchase (SPP) rates, which target generators connected to the national grid and distribution systems of mini-grids or isolated grids. We found for the off-FiT tariff the total amount needed to support the same number of customers by solar and hydro-mini grids versus diesel would be of 31.5 millionUS$, or a premium of 0.11US$/kWh to the present current SPPs tariff of 0.24US$/kWh for PV. We also found that a technology specific FiT tariff would be most suitable to attract national and international investors by providing a rate of return that compensates the risk of the investment. The overall support is comparable to the 36 millionUS$ that the government currently subsidizes and allocates to diesel mini-grids in country, and this shows the potential for a long-term renewable energy strategy for mini-grid areas.
Abstract
Silicon (Si) materials for use in Lithium ion batteries (LIBs) are of continued interest to battery manufacturers. With an increasing number of commercially available Si materials, ...evaluating their performance becomes a challenge. Here, we use an empirical fitting function presented earlier to aid in the analysis of galvanostatic charge‐discharge data of commercial Si half‐cells with relatively high loading. We find that the fitting procedure is capable of detecting dynamic changes in the cell, such as reversible capacity fade of the Si electrode. This fading is found to be due to the highly lithiated Li
2
Si
Li
3.5
Si phase and that the behaviour is strongly dependent on the potential of this phase. EIS reveals that the Si electrode is responsible for the reversible behaviour due to progressive loss of Li
+
leading to increasing resistance. SEM/EDX and XPS characterization are also employed to determine the origin of the irreversible resistance growth on the Si electrodes.
The galvanostatic charge–discharge (GCD) behaviour of silicon (Si) is known to depend strongly on morphology, cycling conditions and electrochemical environment. One common method for analysing GCD ...curves is through differential capacity, but the data processing required necessarily degrades the results. Here we present a method of extracting empirical information from the delithiation step in GCD data for Si at C-rates above equilibrium conditions. We find that the function is able to quickly and accurately determine the best fit to historical half-cell data on amorphous Si nanowires and thin films, and analysis of the results reveals that the function is capable of distinguishing the capacity contributions from the Li3.5Si and Li2Si phases to the total capacity. The method can also pick up small differences in the phase behaviour of the different samples, making it a powerful technique for further analysis of Si data from the literature. The method was also used for predicting the size of the reservoir effect (the apparent amount of Li remaining in the electrode), making it a useful technique for quickly determining voltage slippage and related phenomena. This work is presented as a starting point for more in-depth empirical analysis of Si GCD data.
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