China’s Renewable Curtailment Highlights Growing Global Grid Bottlenecks

China’s rapid expansion of renewable energy is colliding with limits in its electricity network, leading to a sharp increase in wind and solar generation that cannot be used. The trend is also appearing in other major electricity markets, raising concerns that insufficient grid capacity could increasingly constrain global decarbonization efforts.

China rejected an estimated 360 terawatt-hours of clean electricity between January and June 2026, according to analysis by Global Energy Monitor and the Centre for Research on Energy and Clean Air cited by Reuters. That was 49% more than during the same period in 2025 and was equivalent to roughly a year of electricity consumption in Mexico.

The phenomenon is known as renewable curtailment. It occurs when wind or solar installations are capable of producing electricity but system operators reduce or stop their output because the grid cannot accommodate the generation, demand is insufficient in the relevant location, or other operational constraints take priority.

The scale of the problem in China is disputed. The National Energy Administration reported that 8.6% of potential solar generation and 9.1% of wind generation were curtailed during the first half of 2026. Global Energy Monitor and CREA, using weather-adjusted estimates intended to account for unreported curtailment, calculated that approximately 26.1% of combined wind and solar output was rejected.

Whatever methodology is applied, the underlying issue is becoming increasingly important as China continues to install renewable generation at a scale unmatched by any other country.

Grid Capacity is Struggling to Keep Pace

China’s renewable buildout has created a growing mismatch between generation capacity and the infrastructure required to transport electricity from where it is produced to where it is needed.

Large wind and solar developments are frequently located in regions with strong renewable resources but relatively limited local demand. Moving that electricity towards major industrial and urban centres requires extensive transmission infrastructure.

Analysts also point to contractual arrangements that guarantee operating hours or electricity purchases from coal-fired power stations. These arrangements can reduce the ability of grid operators to replace conventional generation with renewable electricity when solar and wind output is high.

The implications extend beyond the electricity wasted during periods of curtailment. Renewable developers increasingly need to account for the possibility that their plants will not be allowed to sell all of the electricity they can generate.

That uncertainty can affect project revenue, financing assumptions and investment returns.

Reuters reported that curtailment pressures, together with changes to China’s renewable pricing system, have contributed to a 66% decline in new solar installations so far in 2026. Developers are increasingly considering solar projects paired with battery storage, which can store electricity during periods of grid congestion and discharge it later when capacity becomes available.

Curtailment is Becoming an International Problem

China represents the largest example, but renewable curtailment is increasing across several electricity markets.

In Australia’s National Electricity Market, wind and solar curtailment reached 2.93 TWh during the first half of 2026, a 37% increase from a year earlier. Around 7% of potential wind and solar generation was curtailed during the period.

Japan rejected approximately 2.35 TWh of renewable electricity, 34% more than a year earlier and equivalent to around 4% of renewable generation.

India, another rapidly expanding solar market, curtailed 8.13 TWh of solar electricity during the quarter ending in June, equivalent to approximately 14% of its solar production for the period.

These figures illustrate a broader transition challenge. Renewable generation facilities can often be developed considerably faster than major electricity networks.

The International Energy Agency estimates that more than 2,500 GW of renewable generation, energy storage and large electricity demand projects are currently held in grid connection queues globally. The agency says annual grid investment will need to rise by approximately 50% from current levels of around $400 billion by 2030 to meet expected electricity demand.

Timing is another obstacle. Planning, permitting and constructing new transmission infrastructure can take between five and 15 years, while solar and wind projects may be completed within one to five years. This difference means renewable capacity can continue expanding faster than the infrastructure required to integrate it.

Storage and Smarter Grids Could Reduce Wasted Power

Building more transmission remains an important part of the solution, but grid expansion alone is unlikely to address curtailment quickly enough.

Battery storage can absorb renewable electricity when production exceeds available transmission capacity or demand. It can then return that electricity to the grid during periods of higher demand.

Chile provides an example of this approach. The country added around 4 GWh of battery capacity during 2025, more than doubling its installed storage capacity, according to Ember analysis cited by Reuters. Much of the new storage was installed alongside solar generation, helping reduce exposure to curtailment.

Existing electricity networks can also be used more efficiently.

The IEA estimates that measures including flexible connection agreements, dynamic line ratings, advanced power-flow controls, reconductoring and other grid-enhancing technologies could unlock capacity for between 1,200 GW and 1,600 GW of projects currently waiting for grid connections.

For policymakers and energy companies, rising curtailment changes the emphasis of the renewable transition. Success can no longer be measured primarily by the number of gigawatts of wind and solar installed.

Transmission infrastructure, storage, electricity-market reform, demand flexibility and digital grid management are increasingly becoming equally important parts of the transition.

China’s experience demonstrates the scale of the challenge. The country has built enormous quantities of renewable generation, but without sufficient flexibility and network capacity, an increasing share of that infrastructure risks operating below its potential.

As renewable deployment accelerates globally, the ability to move, store and manage clean electricity may become as important as the ability to generate it.

Source: www.reuters.com