ODYSSEA Wave power

Overview

Wave power has long been considered as one of the most promising renewable energy resources. As wind waves (i.e., the wave generated by the wind) propagate over sea surface, they transfer energy along their direction of propagation. This wave energy (measured in Joules) is being transferred from deep to transitional and nearshore waters, where it is dissipated along the breaker zone. Wave power, expressed as the rate of wave energy production (Joules per sec = Watt), is being exploited by the Wave Energy Converters (WECs) located either onshore or in offshore waters. At deep waters (i.e., at waters with depth higher than half wavelength), the wave power depends on the wave height, the wave period and the water density, as:

          (1)

where, ρ is the water density (~ 1025 kg/m3), g is the gravitational acceleration (~ 9.81 m/s2), Hmo is the modal significant wave height (in m) and Te is the wave energy period (in sec). As some of these parameters are considered as constant at typical values, the above equation simplifies into:

         (2)

where P is the deep-water wave power in kW/m of wave front length.

In Marinomica, the offshore wave power computation is based on the above simplified formula, using the CMEMS data products to cover the whole Mediterranean Sea. The wavelength λo at deep waters is computed from:

                      (3)

where λo is the wavelength (in m) and T is the wave period (in sec).

The energy wave period Te is obtained as integrated by-product, computed based on the moments of the wave spectrum, as:

                           (4)

where m-1 and mo are the first and zero-moments of wave period, taken as

sea_surface_wave_mean_period_from_variance_spectral_density_inverse_frequency_moment (MWP)

and

sea_surface_wave_mean_period_from_variance_spectral_density_ second_frequency_moment (MWP), respectively. Wave power is integrated over wave direction increments of 22o, defined by sea_surface_wave_ from_direction (VMDR).

 

The Marinomica Wave Power product has geographical coverage from 18.125oW to 36.2917°E and from 30.1875oN to 45.9792oN.

The product contains wave power calculation on a daily basis and wave power forecasts for the next 2 days, based on data provided by CMEMS product (MEDSEA_ANALYSIS_FORECAST_WAV_006_011).

The datasets involved in the calculation are:

sea_surface_wave_significant_height (SWH)

sea_surface_wind_wave_mean_period (WW)

sea_surface_wave_mean_period_from_variance_spectral_density_ inverse_frequency_moment (MWP)

sea_surface_wave_mean_period_from_variance_spectral_density_ second_frequency_moment (MWP)

sea_surface_wave_from_direction (VMDR)

The algorithm was initially developed by DUTH, was checked by Technion and was industrialized by GTD.  The work consisted in adding configuration support, integrating automatic source data download from CMEMS,  adding error handling & console logging, and generating NetCDF compliant output files. After algorithmic industrialization, the product was wrapped into a Docker image based on the WPS 2.0 framework developed by CLS.

Variables

wavepower


Geographical coverage
Temporal coverage   
2020-03-26 00:00:00 / TODAY + 3

Latitude = 30.1875/45.97; Longitude =-18.125/36.29

Vertical coverage
0

Spatial resolution
1/25 degree

Update frequency
daily

Producer
ODYSSEA