Between 0540 and 2140 hours on January 31 2016 the Gorona del Viento (GdV) wind-hydro plant supplied the island of El Hierro with 100% of its electricity from renewables. This short post provides plots of the REE grid data for that day and adds a few provisional observations.
January 31 was undoubtedly a pre-planned test. Press announcements had already been prepared, and conditions were right (“The councillor of Gorona del Viento, Juan Pedro Sánchez, states that the predictions for today are good, and in case of a reduction in wind the water accumulated in the upper reservoir gives us the possibility of responding immediately with hydro to continue filling all of El Hierro’s demand”). It was a also a Sunday, when demand was at a minimum. The test of August 9, 2015, where GdV achieved 2 hours of 100% renewables generation, was on a Sunday too.
Here are the REE grid data for January 31st:
The plot divides itself into four periods:
0000-0540: Routine operations. Diesel running in baseload mode. Wind curtailed at about 6MW, about half the 11.5MW capacity of the wind farm. Generation matched to demand by sending surplus wind to pumping.
0540-1200: Diesel shut down. Demand supplied 100% by wind, still curtailed at about 6MW. Generation again matched to demand by sending surplus wind to pumping.
1200-2150: Abrupt decrease in wind generation at 1200 (not caused by decreased wind speed according to the El Hierro airport records – my guess is that some of the turbines were shut down). After that wind and hydro in an almost exact 50:50 ratio (28.5MWh wind, 28.4MWh hydro). This plus the fact that the transition occurred at 12.00 suggests that this was also a pre-planned part of the test and not a result of grid instability problems.
2150-2400: Routine operations.
Here are the data for the August 9, 2015 test for comparison purposes:
In this test GdV ran on 100% wind for less than an hour and with a combination of hydro and wind – with hydro dominant – for less than two hours. The sixteen hours of 100% renewables achieved in the current test therefore represents progress of a sort. But there are 8,760 hours in a year.
For those who are interested there is now a permanent link to the live El Hierro grid monitor in the right margin of this page.