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    Solar Plus Battery Storage: Why the Business Case in the Baltics Changed

    Need Solar EngineeringAugust 18, 20267 min read

    Three Revenue Streams, Not One

    A commercial battery in the Baltics rarely pays for itself on one use case. It pays because it stacks three:

  1. Self-consumption shifting.: Store the midday solar surplus and use it in the evening instead of exporting it cheaply and buying it back expensively.
  2. Peak shaving.: Your distribution tariff is partly driven by your highest measured demand. Shaving those short peaks cuts a fixed monthly cost that solar alone cannot touch.
  3. Frequency reserve markets.: Since the Baltic grids joined the continental European system, the region procures its own balancing reserves. Batteries are the fastest-responding asset available and are paid for being ready.

    4. Why Volatility Is the Key Variable

    A battery earns from the *spread* between cheap and expensive hours, not from the average price. In the Baltic bidding zones the daily spread regularly exceeds EUR 60-120/MWh, and on windless winter evenings far more. A system that cycles once a day against a EUR 80/MWh spread earns meaningfully more than the same battery in a flat-price market.

    Sizing: The Most Common Mistake

    Oversized batteries are the most frequent error we see in tender documents. The useful rule for a commercial site:

  4. Power (kW): size to your peak shaving target, typically 20-40% of your maximum demand
  5. Energy (kWh): 1.5 to 2.5 hours of that power rating for a self-consumption and peak shaving duty
  6. Only go longer if you are chasing energy arbitrage as the primary revenue

    7. A 300 kWp solar array on a two-shift factory is usually well matched by a 150 kW / 300 kWh battery - not the 1 MWh a supplier may propose.

    Worked Example

    Manufacturing site near Riga, 500 kWp solar, 250 kW / 500 kWh battery:

  7. Battery investment: EUR 190,000
  8. Extra self-consumption captured: 90 MWh/year, worth EUR 9,000
  9. Peak demand reduced by 180 kW, saving EUR 12,000/year in capacity charges
  10. Frequency reserve availability income: EUR 15,000-25,000/year
  11. Annual benefit: EUR 36,000-46,000; payback 4-5 years

    12. Safety and Siting

    Lithium iron phosphate (LFP) is the default chemistry for commercial installations: lower energy density than NMC, but far better thermal stability. Outdoor containerised systems avoid most fire-compartment complications; indoor installations need dedicated fire detection, ventilation and separation agreed with the fire authority early in the design.

    Do Not Retrofit Blindly

    If you already have solar, adding storage is straightforward electrically - but only worth it if your export share is high or your demand peaks are sharp. We start every storage study with 15-minute interval meter data. Without it, any battery recommendation is guesswork.

    Send us a year of interval data and we will tell you whether a battery pays on your site - including when the answer is no.