4 research outputs found
Impact of long-term resource variations on wave energy Farms: The Icelandic case
Four decades (between 1979 and 2018) of the wave energy resource around Iceland are analysed in the present paper via the ERA5 reanalysis, the newest reanalysis of the European Centre for Medium-Range Weather Forecasts. While the overall long-term wave trend observed is unremarkable, particularly between the last two decades, in the northern area, near Greenland, a substantial increase of the wave energy resource is detected. In addition, an exceptional decade (between 1989 and 1998) with an extraordinarily high wave energy resource (increasing over 15% with respect to the previous decade) is observed, which emerges due to high values of the indices corresponding to teleconnection patterns, such as the Arctic Oscillation or the East Atlantic pattern. This increase of the total wave energy resource results in more frequent extreme events (up to 35% of the total resource) and, as a consequence, the exploitable wave energy (excluding these extreme events) does not increase proportionally. However, a substantial impact on WEC average power generation is observed, with over 500 kW of difference between two subsequent decades in a WEC farm of 45 devices, meaning that the analysis of long-term resource variations is crucial for an accurate design of different components in the WEC farm
Evaluation of Lebanon’s Offshore-Wind-Energy Potential
The only regional evaluation of Lebanese wind-energy potential (National Wind Atlas) dates back to 2011 and was carried out by a United Nations agency. In this work, data from the most recent reanalysis (ERA5) developed at the European Center for Medium Range Weather Forecast (ECMWF), corresponding to the 2010–2017 period, were used to evaluate Lebanese offshore-wind-energy potential. In the present study, wind power density associated to a SIEMENS 154/6 turbine was calculated with a horizontal resolution of 31 km and 1 hour time steps. This work incorporated the impact of air density changes into the calculations due to the seasonal evolution of pressure, temperature, and humidity. Observed average offshore air density ρ0 was 1.19 kg/m3 for the 2010–2017 period, but if instead of ρ0 , hourly ρ values were used, seasonal oscillations of wind power density (WPD) represented differences in percentage terms ranging from −4% in summer to +3% in winter. ERA5 provides hourly wind, temperature, pressure, and dew-point temperature values that allowed us to calculate the hourly evolution of air density during this period and could also be used to accurately evaluate wind power density off the Lebanese coast. There was a significant gradient in wind power density along the shore, with the northern coastal area exhibiting the highest potential and reaching winter values of around 400 W/m2 . Finally, this study suggests that the initial results provided by the National Wind Atlas overestimated the true offshore-wind-energy potential, thus highlighting the suitability of ERA5 as an accurate tool for similar tasks globally. View Full-Tex