THE Luzon grid experienced its first 'red alert' of the year on April 16, which eventually resulted in manual load dropping — i.e., temporary blackouts — in some areas of Luzon at about 4 p.m. The circumstances were brought on by an unwelcome, but probably not surprising, shortage of supply. At the time, 19 power plants were on forced outages, and three more were running at derated capacities, making more than 2,100 megawatts available to the grid.As defined by the National Grid Corp.
It must also be at the right voltage, which ensures that it reaches the wall socket where you plug in your rice cooker at the required 220 volts, and it must be at the right frequency – 60 hertz plus or minus about 0.05 Hz, which is the frequency of the alternating current that the vast majority of electrical things run on.All three requirements — supply, voltage and frequency — are a bit of a problem for renewable energy sources.