Got more sun than wires? That is the grid reality in 2025. Solar buildouts are racing ahead while transmission upgrades crawl. The result: clean electrons getting turned away at the door. The fix is not waiting a decade for new lines. It is deploying battery storage, grid-forming inverters, and flexible demand right now.

The problem

Solar curtailment is no longer a niche headache. In California, curtailment jumped 29% in 2024, with solar responsible for roughly 93% of curtailed energy, as reported by the U.S. Energy Information Administration and industry trackers. Midday surplus plus transmission bottlenecks equals clean energy left on the table, as noted by the EIA and sector coverage in Today in Energy and PV Tech. CAISO’s own daily curtailment reports show how often spring shoulder-season peaks force operators to dial down PV output, hour by hour, day by day (CAISO curtailment reports).

Australia is seeing the same crunch. AEMO’s National Electricity Market had several utility-scale solar plants curtailed more than 25% in 2024, with an average curtailment of about 4.5% due to congestion and grid strength constraints, according to PV Tech. This is becoming a global pain point, not a one-off anomaly.

The fix: batteries, grid-forming inverters, and flexible assets

Battery energy storage soaks up excess midday solar and shifts it to evening peaks. That alone cuts curtailment while improving capacity value. In California, the buildout of utility-scale batteries is already changing the curve. Early 2025 data shows curtailment trending down on the back of storage additions, as covered by pv magazine.

Grid-forming inverters are the other game changer. Unlike traditional grid-following inverters, grid-forming units can set voltage and frequency, contribute virtual inertia, and deliver fault current. Translation: they make a renewables-heavy system act like a stable, synchronous grid. Australia is moving first in a big way. AEMO reports a near century of grid-forming battery projects in the pipeline, with 10 operational sites totaling about 1,070 MW already proving stability services, per Energy-Storage.news. Government-backed programs are accelerating this, with ARENA highlighting more than 2 GW and 4.2 GWh of grid-forming battery capacity supported to deliver system strength traditionally provided by spinning machines (ARENA). The Clean Energy Council’s latest report tracks the rapid uptake and the shift toward advanced inverter capability across the fleet (Clean Energy Australia 2025), and transmission owners like Transgrid are contracting grid-stabilising batteries to harden weak parts of the network (Transgrid).

Flexible demand is the third leg. EV fast chargers and smart home assets are joining ancillary services and demand flexibility programs. In Great Britain, the Demand Flexibility Service aggregated more than a million customers and delivered several gigawatt-hours of peak reductions across events, with supplier programs tapping EV charging, home batteries, and smart devices to respond in minutes. See results and program details from the operator and industry analyses: NESO DFS, NESO results, and Solar Power Portal. The lesson is simple: flexible assets absorb and shift energy when the grid cannot move it fast enough.

Receipts

• California’s solar and wind curtailment rose 29% in 2024, dominated by solar, per the EIA and PV Tech. CAISO’s daily reports capture the operational reality.
• Early 2025 coverage shows California’s curtailment easing as batteries scale, with a 12% reduction cited by pv magazine.
• Australia’s grid-forming battery pipeline approaches 100 projects, with 10 operational sites totaling roughly 1,070 MW, according to Energy-Storage.news, backed by ARENA’s multi-gigawatt program (ARENA).
• EV smart charging and flexible demand delivered meaningful peak reductions in the UK’s DFS, with program approvals and performance documented by Ofgem/ESO announcements and NESO results.
• U.S. battery storage financing is scaling fast. Recent tax equity and debt packages for large BESS projects include Plus Power’s $160 million for ISO-NE projects and additional construction financing, reported by Energy-Storage.news and PR Newswire. Case-level financing details appear in counsel announcements such as Sheppard Mullin.

What to do next

• Pair new and existing solar with right-sized BESS to absorb midday surplus and arbitrage into evening peaks.
• Specify grid-forming inverter capability for new batteries and retrofit where practical to improve voltage, frequency, and fault support in weak grids.
• Enroll EV fast charging hubs and smart devices in demand flexibility and ancillary services programs to turn flexible load into a curtailment buffer, following the UK’s DFS model (program info).
• Use mature financing structures, including tax equity and transferability, to scale storage rapidly. Recent deals like Plus Power’s highlight bankable paths (case study).
• Work with system operators on near-term grid strength upgrades and local stability services using batteries, as seen in Australia’s AEMO and ARENA-backed projects (ARENA, AEMO pipeline).

We do not have a solar problem. We have a timing and grid physics problem. Batteries, grid-forming inverters, and flexible demand fix both. Keep building solar. Let advanced storage and smarter loads do the heavy lifting until the wires catch up.