Risk assessment of wind droughts over India

Gangopadhyay, Anasuya; Sparks, N. J.; Toumi, Ralf; Seshadri, Ashwin K

doi:10.18520/cs/v122/i10/1145-1153

Cited by 4 publications

(2 citation statements)

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“…With increasing renewables, the management of variability in a renewable-rich electricity grid becomes crucial. The integration of wind energy is challenged by variability on different time scales (interannual, seasonal, diurnal, and minute to minute) [2][3][4][5][6][7]. Smoothing of wind generation or reduction of variance in the aggregate generation is required for reducing variability and fluctuations in the electric grid.…”

Section: Introductionmentioning

confidence: 99%

Beneficial role of diurnal smoothing for grid integration of wind power

Gangopadhyay

Seshadri

Toumi

2023

Environ. Res. Lett.

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Smoothing of generation variability, i.e., reduction of variance in the aggregate generation is crucial for grid integration of large-scale wind power plants. Prior studies of smoothing have focused on geographical smoothing, based on distance. In contrast, we propose a novel concept “diurnal smoothing” that depends on spatial variations in the timing of seasonal-mean diurnal cycle peak. Considering the case of India, which experiences a strong diurnal cycle of wind-speed, we show how spatial heterogeneity in the wind diurnal cycle can be exploited to smooth wind power variability over and above geographical smoothing. For any given separation distance between sites, the hourly wind speed correlation is highly variable. Difference in timing of the diurnal cycle peak is an important factor for explaining this variability and we define smoothing from differently timed seasonal-mean diurnal cycle as “Diurnal smoothing”. We show that apart from separation distance, the diurnal cycle is crucial for correlation among sites separated by 200 km or more with strong diurnal cycles (amplitude more than approximately 0.5 m/s). Thus, diurnal smoothing is a vital factor in the aggregation of large wind power plants, and grid integration is benefited by considering (in addition to distance) new wind plant sites with largely separated diurnal cycles, especially those differing by roughly 12 hours. Such diurnal smoothing is relevant for regions across the world with strong wind speed diurnal cycles. Ultimately grid integration depends on variations in total wind and solar generation and demand. Hence, their combined effects must be studied.

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Section: Introductionmentioning

confidence: 99%

Beneficial role of diurnal smoothing for grid integration of wind power

Gangopadhyay

Seshadri

Toumi

2023

Environ. Res. Lett.

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“…It has generally been defined based on an energy deficiency and, thus, wind threshold [53][54][55][56][57]. Also, atmospheric conditions related to these phenomena have been studied [36,58,59].…”

Section: Introductionmentioning

confidence: 99%

Low wind climatology (1979-2018) over Europe from ERA5 reanalysis

Gutiérrez

Molina

Ortega

et al. 2023

Preprint

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Research and wind speed assessment has increased lately among other things, due to its interest as a renewable energy resource. Whereas mean values and trends are commonly studied, less attentions is paid to the evaluation of extremes. In terms of lower winds, it is difficult to find agreement on a definition for those conditions. Here, the long-term characterization of low wind values over oceanic and land regions in Europe is assessed from hourly data of ERA5 reanalysis for the period 1979-2018. An absolute threshold (cut-in) related to a generalized wind power curve is used. The number of hours below cut-in threshold (3 m/s) present a reasonable agreement with the available observations, with annual values around 3000-4000 h for most of the locations over Europe, although severe limitations are found to properly represent wind speed field over mountainous areas. Important differences in the amount of hours below cut-in threshold are obtained between northern and southern regions of the domain, where the overall more complex orography and coast line seems to play a relevant role. Interannual and seasonal low wind variability show differences larger than 20-25\% for both timescales. Atlantic Ocean and Mediterranean regions behave differently, but both with less low wind values than land regions. In terms of persistence, analysis of low wind spells indicate that the largest ones, on annual averages, can reach up to 120 consecutive hours (4-5 days) over many land areas. Overall, mean hourly wind spells range from 10 to 20 h, with more than 200 episodes per year

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Low-wind climatology (1979–2018) over Europe from ERA5 reanalysis

Gutiérrez,

Molina,

Ortega

et al. 2024

Clim Dyn

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Research on wind speed characteristics is of interest for many disciplines from renewable energy to ecology. Whereas mean values and trends are commonly studied, less attentions is paid to the evaluation of other features such as low-wind conditions. However, there is no clear definition of “low-wind” on the literature. Here we propose the Beaufort scale to characterize low-wind values over Europe through a fixed threshold of 3.3 m/s (“light breeze" category). Climatological (1979–2018) assessment is performed using ERA5 reanalysis hourly data. The limited amount of observational stations indicate a 40-year averaged amount of around 3500 low-wind hours/year, comparable to the corresponding ERA5 reanalysis cells, which shows severe limitations over mountainous areas. The European domain features a strong north–south low-wind hours gradient. Remarkable patterns are obtained over coasts and complex orography regions. Seasonal low-wind variability range around 20–25% for most of the regions, and interannual coefficient of variability from 0.05 to 0.17. Oceanic regions present smaller low-wind values than land areas, with Atlantic and Mediterranean regions behaving differently. The largest annual spells (consecutive) hourly low-wind episodes are within the range from 5 to 10 days, (from 120 to 240 h) over many land areas. Annual mean hourly wind spells typically extend from 15 to 25 h, with more than 200 episodes.

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Risk assessment of wind droughts over India

Cited by 4 publications

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Beneficial role of diurnal smoothing for grid integration of wind power

Beneficial role of diurnal smoothing for grid integration of wind power

Low wind climatology (1979-2018) over Europe from ERA5 reanalysis

Low-wind climatology (1979–2018) over Europe from ERA5 reanalysis

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