Why Does Intermittent Renewable Energy Production Require Energy Storage?

Intermittent renewable energy production requires energy storage because electricity supply from sources such as wind and solar does not always coincide with demand. Storage absorbs surplus electricity when production is high and releases it when production falls, helping maintain a reliable electricity supply.

This is an SL and HL concept in Subtopic 7.2, Energy sources: uses and management.

The Mechanism

Intermittency means that energy output varies because it depends on environmental conditions. Solar panels produce no electricity at night and less during cloudy weather, while wind turbines generate little electricity when wind speeds are too low or too high.

Electricity grids must continuously balance supply and demand. If production exceeds demand, electricity may be curtailed, meaning potential renewable output is deliberately wasted. If production falls below demand, shortages may occur unless another source can respond.

For example, the Hornsdale Power Reserve in South Australia stores electricity in a large battery and can respond rapidly to fluctuations in supply and demand. Storage can therefore improve energy security while reducing dependence on fossil-fuel backup.

A common misconception is that all renewable energy is intermittent. Hydroelectric and geothermal power can often provide more controllable output, whereas wind and solar are weather-dependent. Storage is also not the only solution: grid interconnection, demand management and a diverse energy mix can increase reliability.

Exam Technique

For an explain question, establish the causal chain: variable renewable output creates a mismatch between supply and demand; storage captures surpluses and releases energy during deficits. For an evaluate question, also consider cost, mining impacts, storage capacity, energy losses and environmental justice, including how battery mineral extraction may affect local communities.