Many people still cling to an outdated notion: when the sun sets, solar energy disappears. This judgment is no longer valid in today’s context. The true transformation of energy reality is not solely due to solar panels, but also to batteries. When batteries become affordable, the sunlight that is not fully utilized during the day can be stored and released steadily at night.
The decline in battery prices is the starting point of this entire narrative. Since 2010, the cost of lithium batteries has plummeted by 90%, and there appears to be no end in sight. Several battery manufacturers and research institutions anticipate that, with process simplification, reduced material usage, and ongoing scale expansion, battery costs will continue to decline significantly.
As a result, solar energy combined with battery storage has become economically viable. Based on recent actual projects, the overall generation cost of such systems generally falls between $60 and $80 per MWh. In contrast, the comprehensive cost of newly built natural gas power plants, even without accounting for carbon taxes and other social costs, remains between $90 and $120 per MWh, and is entirely subject to international natural gas prices and geopolitical factors.
This transition is particularly crucial for subtropical regions. The disparity in solar energy generation between winter and summer is relatively small, and output is stable. With several hours of storage, it can adequately meet daily electricity demands. In high-latitude countries like the UK, batteries are equally indispensable, albeit for slightly different purposes. In addition to solar energy, they complement wind power: when strong winds generate excess electricity in the dead of night, causing electricity prices to drop to negative levels and leading to forced curtailment of wind energy, batteries become a key tool for storing surplus wind energy for peak demand usage.
Many still dismiss the transition with the phrase ‘renewable energy depends on the weather,’ but this statement overlooks the existence of energy storage. As battery costs continue to decline, energy systems are no longer constrained by immediate weather conditions; rather, they depend on overall resource availability and dispatch capability. In a world abundant with wind and sunlight, the truly unstable factors are the prices and supply of fossil fuels.
The idea that ‘there is solar energy at night’ is not just a catchy phrase; it is a conclusion naturally derived from cost curves and system design. When solar and wind energy are paired with long-duration batteries, they become cheaper and more controllable than newly constructed fossil fuel power plants. The question is no longer ‘is it feasible?’ but rather ‘why resist it?’
