Where’s the Best Place in Europe for Behind-the-Meter Solar and Storage in 2025?

If I asked you which European country offers the best returns on behind-the-meter solar and battery storage, you’d probably say: “Somewhere sunny, right?”

Well, not quite. We ran the numbers, and the results might surprise you.

In this blog, we explore supermarket-scale solar PV and battery storage projects across Europe to reveal where behind-the-meter solar and energy storage deliver the highest electricity cost savings, boost self-consumption, and maximise investment returns in 2025.

You can also watch the video here:

Whether you are considering solar PV systems, battery storage in Europe, or combined solar and storage projects, these insights will show why the sunniest countries aren’t always the most profitable.

How We Modelled the Supermarket Energy Project

At Gridcog, we can test the exact same energy project across multiple markets, because we have access to wholesale prices, network tariffs, and non-commodity costs for countries across Europe.

We built a model for a supermarket with 470 MWh of annual electricity consumption, a 300 kW import/export connection, and paying wholesale pass-through, network charges, and what we call “other non-commodity charges.”

These include levies, system costs, and policy or environmental charges, using the most recent 12 months of pricing data. Then, we cloned the project for Belgium, Germany, Spain, France, the UK, Italy, the Netherlands, Portugal, and Ireland.

Scenario One: The Baseline

In our first scenario, we looked at the supermarket’s load without any solar PV or storage. This gave us each country’s energy cost baseline.

Scenario Two: Adding Solar PV

Next, we added a 300 kW solar PV system. This reduces imports and therefore cuts electricity costs linked to volume-based charges billed per kilowatt hour. The site also exports surplus generation and earns the corresponding wholesale price.

Here’s the first surprise:

• In Italy, annual bill savings are about €50,000, the highest of all markets.
  
• Ireland comes second with €42,000, despite lower solar yield, due to consistently high daytime wholesale prices.
  
• The UK follows in third place, benefiting from significant avoided non-commodity charges.

So while solar yield matters, the bigger factor is the avoided cost of energy, whether from high daytime wholesale prices or high per-kWh network tariffs.

Scenario Three: Adding Battery Storage

Then we added a 500 kWh / 2-hour battery energy storage system (BESS), optimised to:

• Increase solar self-consumption
• Reduce network costs
• Arbitrage the wholesale market

With the battery included, the leaderboard shifts:

• Portugal moves into first place with roughly €60,000 in annual savings compared to the baseline, with over a third of those savings coming from avoided network demand charges.
• Italy extends its strong solar case.
• Ireland ranks close behind, where the battery amplifies the value of high energy costs while also shaving peaks and reducing demand charges.

Key Insights for Solar-Only Investments

So, let’s summarise this. For solar-only investments, the combination of high solar yield plus high average daytime wholesale prices is key - Italy shines here. Ireland and the UK perform far better than their weather might suggest, with solar PV delivering strong electricity cost savings against high energy supply prices.

Key Takeaways on Behind-the-Meter Solar and Storage in Europe

For solar-only investments, the winning formula is a combination of high solar yield and high average daytime wholesale prices, and Italy leads here.

But for combined solar and storage projects, the best returns in Europe are not always found in the sunniest countries. Instead, they occur where energy tariffs, market conditions, and wholesale price patterns align most effectively.

That is what our analysis of the last 12 months of data reveals.

Model Your Own Solar and Storage Project with Gridcog

At Gridcog, you can model project scenarios in more than 30 markets worldwide, with regularly updated network tariffs, wholesale and ancillary market prices, and country-specific regulations.

Get in touch if you would like to explore the best opportunities for behind-the-meter solar PV and battery storage in Europe.