What is intermittent power generation? Why is intermittent energy an issue?

To start with what intermittent power generation is- intermittent generation is the irregular
availability of electricity over a certain time period. When weather conditions are less than
favourable for electricity or energy creation, the efficiency of renewable sources decreases,
which can make electricity generation inconsistent and unreliable. Since leading renewable
technologies or sources like solar, hydro, wind and geothermal power are weather dependent,
they can’t provide electricity year-round as single sources.

For example, hydro power, which accounts for about 16% of global power generation, is largely dependent on water currents, precipitation levels and is impacted by the seasons. While Wind power relies on wind speed, concentration and temperature, and solar power depends on the sun’s energy concentration, the amount of diffuse solar radiation and the time of year.

Because of these multiple variances, these sources are considered ‘non-dispatchable’, meaning their output can’t be turned on or off as required to meet society’s fluctuating electricity needs.

Today, not to our surprise, we’re all very used to having electricity on demand. The intermittent
nature of renewables can put immense pressure on the reliability of the current grid system.
Integrating the various variable renewable energy sources into the power grid is challenging, as the grid is designed to ensure power plants produce the right amount of energy, at the right time, to meet demand.

Because the grid has super limited storage capacity, the balance of supply and demand needs to be carefully calculated. Consistency and predictability are the two major and important factors in energy generation to avoid blackouts.

There are times when renewable sources generate excess power that too can’t be handled by
the grid. For example, the case with wind turbines is that, if demand is low but the wind is
blowing at a high speed, the frequency rises too high. Conversely, if demand is high but the
wind speed is low, the frequency falls way below what’s required. These fluctuations can have a very negative impact on the grid and cause damage that can be expensive to repair.

Hence, in order to integrate variable energy sources into the grid, an effective energy storage
system is required to ensure excess energy can be stored for on-demand use as required.
Energy storage can overcome the problem of intermittent power by introducing more and more flexibility to the grid. Solar, wind, hydro and geothermal energy sources can be integrated very effectively, creating a cleaner, low carbon energy mix that can evolve more reliably.

For example, in Denmark, there are not one or two but currently three electric energy storage
facilities that operate using electro-chemical batteries. Pre-existing infrastructure is also being used in creative ways: some companies in the Netherlands are currently experimenting with utilizing excess offshore wind energy to create green hydrogen via an electrolyser located on an offshore oil rig, helping to balance the grid.