Europe’s offshore wind expansion is entering a critical phase where the main challenge is no longer generation, but how to use the electricity being produced. A new report on offshore co-location from Xodus Group warns that without urgent investment in storage and grid flexibility, the continent could waste more than 300 TWh of clean electricity annually by 2040 due to curtailment and grid congestion.

Rapid offshore wind growth outpacing the grid

Offshore wind capacity in Europe is projected to grow from around 37 GW in 2025 to more than 300 GW by 2040. However, transmission infrastructure and storage deployment are not keeping pace. This mismatch is already leading to rising curtailment in key markets such as the UK, Germany, Denmark, and the Netherlands.

In 2024 alone, around 72 TWh of renewable electricity was curtailed across Europe, with congestion management costs reaching approximately €8.9 billion. These losses are expected to increase significantly unless system flexibility improves.

The report highlights that offshore wind farms are increasingly being built faster than grids can absorb their output. When high wind generation coincides with low demand or limited transmission capacity, turbines are forced to reduce output, wasting clean energy and increasing system costs.

Storage emerges as the key solution

The study identifies co-located energy storage as the most immediate and scalable solution to reduce curtailment. By placing batteries or other storage technologies directly at or near offshore wind farms, excess electricity can be captured instead of wasted and released later when the grid has capacity or prices are higher.

Short-duration lithium-ion batteries are expected to lead early deployment, acting as “workhorses” that smooth output and capture short congestion periods. In parallel, longer-duration technologies such as compressed air energy storage and offshore pumped hydro are expected to become the backbone of future offshore energy systems.

According to the analysis, four-hour battery systems can already reduce curtailment by up to 10% at individual wind farms, while also improving revenue stability through participation in balancing and wholesale markets.

The economics: storage becomes increasingly competitive

A key development is the emergence of a combined cost metric for energy and storage (LCo(E+S)), which shows that offshore wind paired with storage could become cost-competitive with standalone wind by 2040.

The report estimates that storage costs could fall by 35–40% by 2040 due to modularisation and supply chain scaling. At that point, hybrid wind-plus-storage systems may no longer be an add-on but a core component of offshore wind infrastructure.

However, today’s economics remain challenging. Offshore storage can still cost up to three times more than equivalent onshore systems due to marine engineering complexity and installation constraints.

Policy barriers slowing deployment

Despite its potential, offshore storage faces significant regulatory obstacles. In the UK, existing Contract for Difference (CfD) mechanisms compensate wind farms for curtailed energy. This reduces the financial incentive to store electricity, since doing so can actually lower guaranteed payments.

Additionally, transmission ownership rules and charging structures in several markets discourage storage integration behind the grid connection point.

The report calls for phased policy reform, including:


Allowing co-location without penalty under CfD schemes
Rewarding curtailment reduction and system flexibility
Scaling hybrid offshore wind auctions under CfD reform
Reforming transmission access and ownership rules

Toward a new offshore energy system

Looking ahead, Europe’s offshore energy system is expected to evolve from radial wind farms connected to shore into interconnected offshore hubs and meshed HVDC networks. These “energy islands” would combine generation, storage, and interconnection in a single offshore system.

Within this architecture, storage is expected to play a central role in stabilising output, reducing congestion, and enabling offshore wind to become a fully dispatchable energy source.

By 2040, the report concludes, offshore wind paired with storage could shift from a niche concept to a mainstream infrastructure model—transforming variable renewable generation into reliable, system-critical power for a net-zero Europe.