The great big solar soak: Batteries are starting to drive up midday electricity prices - Renew Economy

Battery storage is beginning to push up electricity prices at midday as solar generation peaks across the grid. Renew Economy reports that batteries are now competing during high-solar periods, driving up the cost of energy storage at times when it was previously cheap. The dynamic reflects a shift as battery capacity grows: rather than absorbing cheap midday solar power, batteries are becoming selective about when they charge, in response to price signals.

Where this fits

This is a live cost consequence of a renewables-heavy grid trying to firm itself without dispatchable power. As solar capacity expands, the window in which batteries can profitably charge shrinks. Batteries are expensive capital. When their revenue window narrows because supply is abundant and dispersed, the cost per unit of storage rises, pushing the whole-system economics toward higher grid costs. This is the firming problem in motion: a renewables-only path does not eliminate the need to store and shift energy; it multiplies the hardware required and compresses the hours in which that hardware can work profitably.

What it means

Australia's grid is entering a phase where the cheap, abundant midday solar everyone cheered is now too abundant to be economic storage fuel. The grid still needs firm power to bridge the dark hours and cloudy days. Gas plants currently provide that service. Batteries cannot replace them at scale without vast capital deployed for a shrinking margin of work. A firm, fuel-independent generation source, nuclear, would flatten this cost curve by decoupling generation from time-of-day weather. Instead, Australia's path is locked into rising storage costs and continued gas dependence, at a time when global energy security is tightening and supply chains for batteries remain concentrated in China.