⚡ Article summary in 45 seconds
- Most plants on the B23 tariff do not know exactly how much they lose on capacity charges and penalties for exceeding contracted power. The answer usually falls in the range of 80–150 thousand PLN per year.
- More than 60% of the electricity bill under B23 consists of components independent of the energy purchase price – changing your supplier barely moves the needle.
- Peak-shaving with BESS and EMS is the only method that hits the largest cost items at once: the contracted-power charge and penalties for exceedances.
- Plants with annual consumption above 1 GWh achieve a 20–35% reduction in energy costs with a simple payback period of 2.5–4 years without subsidies.
- EAB Solutions provides a free energy profile analysis – so you know which investment makes sense in your specific case.
Table of contents:
- What is the B23 tariff and who uses it?
- Cost structure – what are you really paying for?
- Why is the B23 tariff expensive and hard to control?
- Methods for optimizing costs
- BESS as a peak-shaving tool
- The role of EMS in managing the B23 tariff
- How to calculate savings potential?
- Most common mistakes
- FAQ
What is the B23 tariff and who uses it?
The B23 tariff applies to consumers supplied from the medium-voltage (MV) grid. It is a single-zone tariff – active energy is billed at one rate around the clock. It differs from the B21 tariff, which splits the day into zones, and from low-voltage tariffs (C21, C22).
It is used mainly by production plants operating continuously or in multiple shifts, industrial cold stores, large logistics warehouses, and service facilities with high, stable power demand. Typical contracted power ranges from 300 kW to several MW.
It is worth distinguishing the distribution tariff (set by the DSO – distribution system operator) from the supply tariff (set by the energy retailer). When a company talks about “energy costs under B23”, it usually means the combined bill covering both components. Optimization must address both – and that is where the real gap opens between plants that pay less and those that overpay.
If your plant draws power from the MV grid and consumes more than 1 GWh per year – there is a good chance there is a line item on the bill that can be reduced without changing the production process.
Cost structure in the B23 tariff – what are you really paying for?
The electricity bill under B23 is not a single line item but several independent components settled by different mechanisms. Understanding each one is a prerequisite for sensible optimization – because each requires a different tool.
| Cost component | Characteristics | Optimization potential |
|---|---|---|
| Active energy (kWh) | Single-zone – one rate around the clock. | Reduction through on-site PV and process management. |
| Capacity charge – capacity market | Charged according to capacity obligation (PSE rates for the given year). Applies in grid-stress hours. | Partial reduction through DSR (Demand Side Response) – load reduction on DSO request. |
| DSO contracted power (PLN/kW/month) | Fixed cost independent of consumption – charged on power declared in the contract. | Renegotiation after a profile audit + protection against exceedances via EMS/BESS. |
| Penalty for exceeding contracted power | Up to 5× the standard rate for each kW of exceedance in a 15-minute interval. | Near-complete elimination with predictive EMS deployment. |
| Variable and fixed distribution charges | Partly dependent on energy volume, partly on connection level. | Reduction through self-consumption from PV and BESS. |
| Excise tax | Statutory. Relief for energy-intensive consumers (>1 GWh/year) under Art. 31d of the Excise Tax Act. | Excise refund when conditions are met – verify with a tax advisor. |
Key observation: in a typical production plant on B23 with 2 GWh annual consumption, the contracted-power charge and network components together account for 55–65% of the total bill. Active energy – the part most supply negotiations focus on – is only 35–45%.
If your plant’s energy optimization so far has consisted mainly of negotiating the purchase price – you are working on less than half the potential.
Why is the B23 tariff expensive and hard to control?
The main problem is not the price of energy but the penalty mechanism. Penalties for exceeding contracted power are settled on the basis of a 15-minute demand window – a single short peak in the month is enough to trigger a penalty for 100% of the billing month. Traditional SCADA and ERP systems record these events historically but do not generate advance alerts.
The second mechanism that creates invisible costs is overstated contracted power. Plants rarely renegotiate it, fearing the risk of insufficient capacity. As a result, they pay a fixed monthly cost for power they statistically use only 60–70% of the time.
Numerical example: A plant with 500 kW contracted power that, in one 15-minute period, draws 650 kW will pay a penalty on 150 kW of exceedance. At a rate of up to 5× the standard charge, that is a one-off cost of roughly 8–15 thousand PLN – recurring month after month if nobody monitors the power profile in real time.
The first step to lowering the bill is always knowledge: how much and exactly when you exceed contracted power. Without that, even a sound investment decision can be poorly calibrated.
Methods for optimizing costs in the B23 tariff
Effective B23 optimization is not a one-off action – it is a set of complementary measures whose order matters. Implemented in the wrong sequence, they generate cost without proportional benefit.
1. Start with data, not hardware
Before any investment in BESS or PV, a load-profile analysis based on at least 12 months of 15-minute data is essential. It answers: when and how deeply you exceed contracted power, what your actual demand maximum is, and by how much you can safely lower contracted power.
In many plants, simply collecting and analyzing data reveals contracted power is overstated by 15–30%. Renegotiation with the DSO – with no equipment at all – can save on the order of 30–80 thousand PLN per year on the fixed distribution charge alone.
Data from your smart meter or SCADA that you already have is the starting point for the analysis – you do not need a new system for that.
2. Peak-shaving – eliminating penalties at source
Peak-shaving flattens short demand peaks by temporarily supplying the plant from local energy storage before the alarm threshold is breached. EMS monitors demand in real time and triggers BESS discharge automatically.
Under B23 it pays off especially well: every avoided exceedance is a specific amount removed from the invoice. With 5–8 events per year at 10–15 thousand PLN per event, penalty elimination alone can pay back EMS deployment within 12–18 months.
Peak-shaving is not technology for large corporations only – plants with contracted power from 300 kW achieve measurable financial results in the first year.
3. Photovoltaics as a reduction in active-energy purchases
A PV system integrated with EMS and BESS reduces grid draw during daytime hours, directly lowering the active-energy bill. Without BESS and EMS, self-consumption on a typical production profile is 40–55% – the rest goes to the grid at low feed-in prices. Only PV + BESS + EMS raises self-consumption to 75–85%.
PV without EMS and BESS is an investment that leaves part of the potential on the table. PV with full integration is an investment that changes the cost structure of energy.
4. Production schedule management
In plants with a flexible schedule, EMS can automatically shift energy-intensive operations (e.g. line start-up, heating, compressors) outside peak-demand windows. This requires no equipment purchase – only control-system configuration.
This method is often underrated because there is no “installation” invoice. Effects appear from the first month after configuration.
BESS as a peak-shaving tool in the B23 tariff
Electrochemical energy storage (BESS) is the most effective peak-shaving tool for plants on the B23 tariff. It responds in milliseconds, operates without an operator, and – unlike process management – requires no compromise in the production schedule.
| Parameter | Typical values – containerized LFP system |
|---|---|
| Usable capacity | 100–500 kWh (modular scaling) |
| Charge/discharge power | 50–250 kW |
| PCS response time | 100–500 ms standard; <20 ms in FFR mode (requires dedicated PCS) |
| Cycle life (80% DoD) | 4,000–6,000 cycles – over 10 years at 1 cycle/day |
| Round-trip efficiency | 88–93% |
| Installation time | 2–3 days |
Sizing BESS capacity and power requires analysis of the exceedance profile: how deep and how long the plant exceeds the alarm threshold. Oversized BESS wastes CAPEX. Undersized BESS – no effect. That is why historical data analysis always precedes the technical design.
Sizing rule: BESS power should cover the gap between typical demand peak and target contracted power, for longer than the historically longest exceedance + 20% margin.
The EAB Solutions BESS system is installed in 2–3 days. First effects appear on the next billing-month invoice.
The role of EMS in managing the B23 tariff
EMS (Energy Management System) is software that turns meter and sub-meter data into decisions – in real time, without human intervention. Without EMS, BESS is only a reactive energy buffer. With EMS, it becomes a proactive cost-management tool.
In the context of the B23 tariff, EMS performs five key functions:
- Power monitoring at 1-second resolution and alerts as the threshold approaches.
- Demand prediction for the next 15 minutes – BESS reacts before exceedance occurs, not after.
- Optimized BESS charging schedule – charging in the night valley or from PV, discharging at peak.
- Automatic management of flexible loads – shifting processes outside peak windows.
- Monthly reporting with tariff cost analysis – format ready for contracted-power renegotiation with the DSO.
The EMS report is the document that convinces the DSO to lower contracted power – because it shows the plant controls its demand. That is a financial argument, not only a technical one.
How to calculate savings potential?
Before you commit to an investment, a simplified estimate is worthwhile – so you know whether we are talking about 50, 150, or 400 thousand PLN per year. The required data is in documents you already have.
| Input parameter | Where to obtain it |
|---|---|
| Current contracted power (kW) | Distribution contract with the DSO |
| Historical peak demand (kW) | AMI meter or SCADA data – 12 months |
| Contracted-power rate (PLN/kW) | DSO tariff for the current year |
| Penalty rate for exceedance | Distribution contract (up to 5× standard rate) |
| Number and depth of exceedances | Historical 15-minute meter data |
| Annual active-energy consumption | Invoices for the last 12 months |
Example for a plant with 600 kW contracted power and 2 GWh annual consumption:
- Peak demand reduction: 600 → 480 kW (−120 kW) → savings on contracted-power charge: 80–120 thousand PLN/year
- Elimination of 3–5 exceedance penalties per year: 30–75 thousand PLN/year
- Total potential: 110–195 thousand PLN/year
- Estimated CAPEX: BESS 250 kWh + EMS = 380–550 thousand PLN (containerized LFP system, installation, 2026 market)
- Simple payback: 2.5–4 years without subsidies; 1.5–2.5 years with 40% funding
💡 Want to see these figures for your plant? EAB Solutions will prepare a free savings-potential analysis based on your actual data – with no obligation. info@eabsolutions.com.pl
Most common mistakes when managing the B23 tariff
Most overpaying plants make the same mistakes – not from lack of knowledge but from lack of time and tools for day-to-day monitoring. The list below helps you quickly identify where the problem lies in a specific case.
| Mistake | Financial impact | What to do instead |
|---|---|---|
| No 15-minute monitoring | Penalties for months or years – nobody knows | EMS with alerts or at least AMI meter reads |
| Overstated contracted power without verification | Overpaying for capacity reservation you do not use | Power-profile audit + renegotiation with DSO every 12 months |
| BESS without EMS | BESS does not react proactively – 30–40% of potential | Always integrate BESS with dedicated predictive EMS |
| Changing supplier as main optimization | Impact on <40% of bill – rest unchanged | Supplier change as a complement, not a strategy |
| No data before the project | Wrong BESS sizing – exceedances and penalties continue | Min. 6–12 months of 15-minute data before the project |
| Missing excise relief | Overpaying tax at consumption >1 GWh/year | Verify eligibility as energy-intensive consumer (Art. 31d Excise Tax Act) |
Each row in this table is a specific amount you can recover – not once, but every year.
💡 How much is your plant actually losing on the B23 tariff?
- Free energy profile analysis within 48h – based on your data, not industry estimates.
- Full strategy: peak-shaving, BESS sizing, contracted-power renegotiation, funding options, and excise relief.
→ info@eabsolutions.com.pl | ul. Domaniewska 44, 02-672 Warszawa
FAQ – frequently asked questions
The B23 tariff is single-zone – active energy is billed at one rate around the clock. However, the penalty for exceeding contracted power is based on a 15-minute demand window, which creates an economic incentive to control power around the clock. Colloquially people refer to a “B23 peak”, but that is not a formal tariff zone.
Changing supplier affects the price of active energy, which accounts for 35–45% of the bill under B23. The remaining 55–65% – DSO charges, contracted power, penalties – stay the same regardless of supplier. Switching supplier pays off, but as a complement, not as a strategy.
EMS deployment with meter integration and algorithm configuration takes 2–4 weeks. The first results – elimination of exceedance penalties – appear from the first full billing month. Contracted-power renegotiation is possible after 3–6 months of EMS data.
Below 200 kW contracted power, a full EMS + BESS system usually has too long a payback without subsidies. Exceptions are plants with very frequent exceedances or high DSO penalty rates. PV with basic EMS can however pay off from 100–150 kW.
Yes – relief for energy-intensive consumers (Art. 31d of the Polish Excise Tax Act) applies to tax on energy purchased from the grid and is independent of BESS or PV investment. BESS reduces grid purchases, which may affect eligibility – analyze this with a tax advisor before deciding.
See also
Why Monitoring Is Not Enough – How Intelligent Energy Management (EMS) Differs from Classic Measurement Systems
Visualizing energy consumption alone won't lower bills. Classic monitoring shows how much and when you consume energy. Intelligent Energy Management System (EMS) goes a step further: it forecasts, decides and controls devices in real-time.
Why energy monitoring is no longer enough in a production plant
Monitoring consumption is a good starting point, but in the reality of industry it is far from sufficient. An intelligent EMS will stop costs that a consumption chart alone will not.
Energy Prediction in Industry – How Algorithms Predict Peaks and Energy Prices
Rising energy costs, tariff sensitivity, and the growing role of renewables mean industrial plants must act faster, more precisely, and more consciously. Energy prediction enables cost reduction, production stabilization, and limiting the impact of price fluctuations.