The beauty of batteries - Works in Progress Magazine

Keeping the grid stable requires overbuilding generating capacity, driving up costs. Batteries fix that.

All critical infrastructure depends on buffers, inventories, and storage. Water sits in reservoirs and storage tanks; hospitals maintain blood banks and stockpiles of medicines; the financial system relies on reserves and capital buffers. All critical infrastructure, that is, with one exception.<br>The supply and demand of electricity must match exactly at every moment. There is no slack in the system: an electricity grid is a unique market with no inventories at all. If demand exceeds supply even briefly, the frequency of the grid drops, causing equipment to shut off and risking widespread blackouts. If supply overshoots demand, the grid becomes unstable in the other direction, forcing operators to quickly scale back production. Since electricity can’t be stored within the grid itself, the system has been built to maintain balance second by second, under all conditions.

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To make this work, electricity systems rely on layers of complex rules and processes. Power plants are scheduled hours or days in advance based on forecasts. Others are paid just to stay running in case demand spikes or another plant fails. Some are required to operate even when uneconomic, in order to meet reliability rules. Prices are often fixed or averaged across large regions, so they don’t reflect real-time local conditions. These tools keep the system running, but at a high cost.<br>Much of the infrastructure – plants, power lines, and reserves – exists only to cover rare events and sits underused most of the time. The cost of this redundancy is passed on to consumers. This complexity also means electricity markets are less efficient than they could be. Prices and investment don’t reliably reflect scarcity, location, or flexibility. The result is an expensive, inefficient grid that is struggling to keep pace with demand and the transition to renewable energy sources.<br>Batteries offer a way out of this structural bind, giving producers, consumers, and distributors a way of keeping inventories for the first time ever, meaning that their value goes well beyond simply storing excess solar or wind.<br>They can respond in milliseconds, shift between consuming and supplying power as needed, and are controlled entirely through software. This flexibility allows them to take on a wide range of roles within the system: stabilizing frequency, supporting local distribution networks, reducing peak demand, and easing pressure on transmission lines. Because they require no fuel, emit no local pollution, and can be deployed close to where electricity is used, they can often replace several types of traditional infrastructure at once. Rather than being single-purpose assets, batteries adapt in real time to whatever role is most valuable at that moment.<br>The just-in-time energy supply chain<br>Thermal power stations, whether coal‑fired, nuclear, or combined‑cycle gas (a type of plant that uses both gas and steam turbines to improve efficiency and reduce emissions), are fundamentally large heat engines. Like any big piece of industrial equipment, they must be started up slowly. This can involve up to 20 hours of careful temperature ramp‑up to avoid cracking boilers, warping turbine rotors, or shocking reactor vessels.

Combined cycle gas technology

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Marchwood Power

Once online, they can be surprisingly brittle. In deep freezes, for example, the screens that filter debris from incoming cooling water can clog with slushy ice, restricting flow and forcing plants offline just when electricity demand spikes. At the other end of the spectrum, heat waves can shrink water supplies, raise ambient temperatures, and potentially trigger overheating and shutdown.<br>Even in good weather, large units are routinely pulled offline for weeks-long shutdowns to inspect and repair critical components. Technicians may need to replace corroded metal tubes that transfer heat from exhaust steam to cooling water, or to examine turbine blades for hairline cracks or deformation. These procedures are essential to prevent catastrophic failure, but they take time, specialized crews, and careful planning.<br>Decarbonization is adding further complexity. Utility wind and solar are already reshaping the supply curve. Renewables are expected to provide 25 percent of all US generation this year. Solar generation is set to increase by a third in 2025 alone, followed by nearly a further fifth in 2026. The resulting volatility is evident. The North American Electric Reliability Corporation, an industry body that promotes supply reliability, warned in its 2025 Summer Reliability Assessment the growing fleet of ‘intermittent renewable resources drives a risk of emergency conditions in the evening hours when solar generation ramps down and loads...