40 years with batteries & power · independent · vendor-neutral

From audit-grade data
to the arbitrage trading ceiling.

I am Holger Roswandowicz — independent energy engineer and BESS expert. It started with batteries in 1984: as battery charging warden for a helicopter squadron, I ran the pilots' aircraft batteries and the airfields' power supply. Forty years later, batteries are still the work. For 17 of those years my firm has run DIN EN 16247-1 energy audits across industry, biogas, food retail, hotels, airports and municipalities. That practice taught us one thing: the money is lost in contracts, metering and settlement — not in the hardware. Today we bring the same forensic, register-true rigour to battery storage trading the power markets, across 35 markets worldwide.

€35,407
Reference · 9.998 MWp PV park, Bavaria: 14% of annual yield in §51-EEG penalty zones plus a 25.5% settlement gap = €35,407/year cash loss — proven empirically from open market data, without SCADA access.
130+
DIN EN 16247-1 auditsBAFA-certified · since 2008
1.2 GW
PV capacity supervisedGermany
35
power markets liveEurope & worldwide
100%
independentno hardware, no trading book
What we do

One chain — from the meter to the settled trade.

Take the whole chain, or just the piece you need. Always vendor-neutral, always register-true.

⚡ Arbitrage optimization & marketing

Dispatch optimization, the Decke benchmark, revenue strategy, and reconciliation of model against real settlement. The core engine, applied to your battery.

📐 Feasibility & bankability

Grid and site screening, the business case, and an independent bankability view — the honest number before you invest, not the vendor's.

🔍 Energy audit heritage

DIN EN 16247-1 audits, ISO 50001, transformer & load-profile analysis. 17 years of forensic practice — now applied to storage.

🏗️ BESS project development

Permitting, grid connection, sizing and technology selection, EPC and investor brokerage — all the way to commissioning and live trading.

The neutral benchmark

The Decke — the most the market allowed.

€178/MW
Austria, 3 June 2026 · 1 MW·2h battery · perfect-foresight ceiling

For every ≥1 MW battery we compute the Decke: the most it could have earned trading the day-ahead curve with perfect foresight. It is not a promise — it is a neutral reference. Without it, no investor knows whether a battery was traded well or simply left money on the table. That is the real bankability question.

We compute it for 35 markets, from public data, independent of any vendor or trader.

See the live market radar →
Track record

17 years of energy practice, now with AI for storage.

The path from hands-on audits to a data platform that benchmarks batteries against the market.

1984

It started with batteries

Battery charging warden for a helicopter squadron in former East Germany — responsible for the pilots' aircraft batteries and the airfields' power supply, after a four-week course at the Akkumulatorenwerk Zwickau. Forty years with batteries and power systems begin here.

1992

Dipl.-Ing., TU Magdeburg

The engineering degree on top of hands-on practice — three more decades of energy work follow.

SINCE 2008

130+ DIN EN 16247-1 energy audits

BAFA-certified audits across industry, biogas, food retail, hotels, fitness, airports and municipalities — 1.2 GW of PV supervised.

2011

EFFCONTROL load & peak analysis

Our own measurement practice for transformers, KWK, PV and grid — long before it was fashionable.

2025

Stromfee.ai — cashflow forensics for PV

17 years of audit findings turned into a platform: 14% of yield routinely lost in penalty zones and settlement gaps, made visible per asset from open market data.

2026 · NOW

Arbitrage power-trading optimization, globally

The practice it was always meant to be: batteries trading the power markets, optimized to the Decke, across 35 markets — at stromfee.cloud.

Have a battery, a site, or a question?

Call directly — or leave your details and we'll come back to you. International inquiries welcome.

IndependentRegister-true35 marketsHR Energiemanagement GmbH