Všechny Insights
Případová studie
Battery storage for wind turbines: more value from the wind site you already own
Sofie Berggren and Mette Jensen
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A wind turbine produces power when the wind blows, not when the price is right. Battery storage for wind turbines changes that.
Adding battery storage to your existing wind turbines gives you greater control over when the energy they produce is delivered to the grid. By making better use of your existing assets and grid connection, you gain more flexibility, optimise when you sell your energy and unlock new revenue opportunities for your business.
This guide explains how battery storage for your wind turbines works, how you can earn from grid balancing, what shapes your business case and what the numbers look like at two wind sites in Denmark.
In this article
Can wind energy be stored?
Why add a battery to an existing wind turbine?
How wind turbine battery storage works in practice
What shapes the business case
Three ways to run a battery on your wind site
Case: four turbine placements in North Jutland
Case: a smaller wind site on Falster
From wind site to complete solution
Frequently asked questions
Start with your wind site
Can wind energy be stored?
Yes, but not by your turbine itself. Your turbine has no storage of its own: its output follows the wind, and you sell the energy the moment it is produced.
To store wind energy, you need a separate storage system. If you already own turbines, the most practical option is a battery energy storage system (BESS) on the same site, connected through your existing grid connection. The battery charges from your turbine’s output and releases that energy later, when it is worth more or when the grid needs it.
Why add a battery to an existing wind turbine?
On its own, your turbine sells whenever the wind blows, whatever the price. And windy hours are often the hours when prices are lowest, because many turbines produce at the same time.
With a battery on the same connection, the wind still produces the energy, but you decide when it reaches the grid. Storage adds control to generation you already own, within the approved limits of your site. That control creates value in four ways:
What a battery adds to your wind turbines
01
Sell your electricity at better times.
The battery stores wind energy when prices are low and sells it when prices are higher.
02
Capture more usable wind.
Store the wind energy the grid can’t take, and release it during low-wind hours.
03
Offer flexibility revenue.
Earn from approved grid-balancing products when there is capacity and charge available in the battery.
04
Value based on your site.
The value is calculated from your own grid limits and actual costs, not from a generic model.
One site controller decides how the same battery is used across these opportunities. The combined result is optimised, and no MW or MWh is counted twice.
Could a battery pay off on your wind site?
Our specialists can look at your turbines, your grid connection and your production data, and tell you what a battery could add at your site.
How wind turbine battery storage works in practice
The principle is simple: store wind energy when prices are low and sell it when prices rise. One shared controller keeps the combined output of your turbine and battery within your approved site limit.
Here is an illustration of a single day:
Store wind energy · sell when prices rise
00
03
06
09
12
15
18
21
02:00 to 06:00 · Charge
Your turbine sends 2.2 MW into the battery in low-value hours. After four hours, 8.8 MWh is stored.
17:00 to 21:00 · Deliver
The battery delivers 1.98 MW in high-value hours: 7.92 MWh at 90% efficiency.
Your turbine still needs wind
With no wind and no grid import, your battery can’t charge. The day above is an example.
What shapes the business case
Three things shape your business case
Export only
Export + import
Your grid rights
Export only stores wind for later. Grid import opens more trading, subject to import tariffs.
≈3.4 h
10 MWh ÷ 2.95 MW, excl. energy losses
MW sets output, MWh sets duration
Power decides how fast. Energy decides how long.
15 min
metering data per turbine
Your own production data
Sized on your data, not on the turbine’s nameplate.
Your grid rights
The terms of your grid connection set the boundaries. If you have an export-only connection, your battery stores wind energy for later sale. If your connection also allows grid import, more trading opportunities open up, subject to import tariffs. Balancing services depend on your connection being approved and on your battery qualifying for each product.
MW sets output, MWh sets duration
Two numbers describe a battery. Power (MW) decides how fast it can charge or discharge. Energy (MWh) decides how long it can keep going. A 10 MWh battery at 2.95 MW can run for about 3.4 hours, excluding energy losses. The best financial result depends on getting both right for your site.
Your own production data
A good business case starts with your site’s actual production, tariffs, import and export rights. Sizing the battery to your data, rather than to your turbine’s nameplate, is what makes the numbers hold up.
Three ways to run a battery on your wind site
How much a battery adds depends on what your grid connection allows and which markets the battery is qualified for. A simulation of three Vestas turbines in price area DK1 (1 October 2025 to 30 September 2026) shows three steps:
Wind shifting. The battery stores only your turbine’s own power and sells it when the spot price is highest. It does not charge from the grid.
Full stack without grid import. Once the battery is prequalified, it also bids into ancillary services, but it still charges only from your turbine.
Grid import and ancillary services. With grid access for import, the battery can also charge from the grid and use the full revenue stack.
For the three turbines together, annual revenue after grid tariffs rises from DKK 3.0 million without a battery to DKK 11.5 million with grid import and ancillary services.
Three Vestas turbines · DK1 · Oct 2025 to Sep 2026
Annual revenue after grid tariffs, DKK million
3.0
4.3
8.7
11.5
Wind without battery
Wind shifting
Full stack, no grid import
Grid import + ancillary services
+DKK 8.5m
a year with grid import and ancillary services
+DKK 5.7m
a year without grid import, once prequalified
+DKK 1.3m
a year from wind shifting only
What it means for your turbine
Each battery is sized at 1 MW / 2 MWh per MW of turbine power.
Turbine | Battery | Without battery | Wind shifting | Full stack without grid import | Grid import + ancillary services |
|---|---|---|---|---|---|
Vestas V44, 600 kW | 0.6 MW / 1.2 MWh | DKK 0.58m | +DKK 0.24m | +DKK 1.08m | +DKK 1.56m |
Vestas, 900 kW | 0.9 MW / 1.8 MWh | DKK 0.82m | +DKK 0.35m | +DKK 1.58m | +DKK 2.35m |
Vestas V66, 1,750 kW | 1.75 MW / 3.5 MWh | DKK 1.59m | +DKK 0.68m | +DKK 3.07m | +DKK 4.57m |
Figures are net annual revenue after grid tariffs. The uplift is compared with the same turbine without a battery.
Where the wind goes
Share of turbine output
Sold directly
To battery
Curtailed
Wind shifting
61%
32%
7%
Full stack, no grid import
35%
54%
10%
Grid import + ancillary services
75%
10%
15%
With wind shifting, 61% of the wind is sold directly and 32% is moved to higher-priced hours. Without grid import, over half the wind passes through the battery, because it can only charge from your turbine. With grid import, the battery charges mainly from the grid, so 75% of the wind is sold directly.
The figures are scaled linearly from two reference turbines and based on 2025 to 2026 prices. Your production profile, location and grid connection will affect the result, and future spot and ancillary service prices may differ.
Case: four turbine placements in North Jutland
This business case looks at adding battery storage to four existing wind turbine placements in North Jutland, Denmark.
The system is a 3.45 MW battery container, scaled down to 2.95 MW / 10 MWh to fit each placement. With an investment of DKK 11.53 million per placement (excluding VAT), the battery creates new revenue on top of the turbines’ existing wind income.
Case · North Jutland · per placement
2.8 years
Payback, base case
1.7 years
Payback with additional grid access
DKK 11.53m
Investment per placement, excluding VAT
DKK 49.92m
10-year battery and grid access earnings
Annual forecast per placement incl. wind baseline, DKK million
11.88
10.65
10.33
9.21
8.97
8.64
8.52
8.54
8.37
8.27
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
Modelled figures. Payback and earnings exclude existing wind income, operating costs, financing and tax.
Case: a smaller wind site on Falster
A smaller site on Falster shows the same logic at a different scale. Based on the site’s own production data from 2025 to 2026, we recommended a battery sized to its connection and output.
Case · Falster
750 kW
Recommended battery, about 1.5 MWh at 0.5C
DKK 457,210
Wind-only revenue after the producer tariff, from 1,144.4 MWh produced
≈ DKK 2.76m
Indicative annual battery uplift, before commercial fees
For the production-data period, the combined total comes to DKK 3,216,132 after tariffs. The annual uplift and the period figures are calculated separately.
From wind site to complete solution
Adding a battery to your wind site follows four steps:
From wind site to complete solution
1
Qualify the site.
We review your production data, tariffs and import and export rights.
2
Size and engineer.
We design power conversion, storage, site control and your grid connection.
3
Agree market terms.
We settle the aggregator, balance responsible party, products and fees.
4
Deliver and verify.
We install, commission and qualify your system, and monitor it after handover.
Frequently asked questions
Start with your wind site
We validate your grid limits and build the net business case from your own data. To run a precise simulation, we need 15-minute metering data for each turbine and confirmation from your grid operator of whether grid import is possible. Get in touch with our experts.