From 1 January 2027, the way industrial sites connected to the high-voltage (HV) and extra-high-voltage (EHV) grids in the Czech Republic pay for electricity distribution will change.
Over the past few months, we have discussed the upcoming reform with dozens of energy managers, operations directors and finance managers across Czech industry. The same questions keep coming up, so we have collected the ten most common ones and answered them in one place.
If anything remains unclear after reading this article, send us your question in advance and we will answer it during our webinar on Tuesday, 15 September 2026 at 10:00 CET.
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1. What will change from 1 January 2027?
In simple terms, the current reserved-capacity model is being replaced by two capacity-related charges: one based on reserved input capacity and one based on the maximum 15-minute demand.
- Reserved input capacity – the capacity the distribution system operator reserves for your site under your grid connection agreement. Until now, this has not been charged separately. This is at the heart of the change.
- Maximum demand – the highest 15-minute average power demand actually recorded during a given month. Not an average across the month and not a total. A single 15-minute interval can determine the charge.
The network usage charge per MWh consumed remains unchanged.
One important point: reserved input capacity cannot simply be adjusted whenever you want. Changes are only possible in specific circumstances and require an amendment to the grid connection agreement. In addition, if you later request an increase in reserved input capacity, the distribution system operator may not necessarily be able to grant it.
Because reserved input capacity will directly affect your electricity distribution costs under the new structure, it may make sense to reduce excessive capacity — but without eliminating the headroom your site may need for future growth. See Question 6.
2. Who will be affected — and who will not?
The change applies to all delivery points connected at HV and EHV levels in the Czech Republic, broadly meaning sites connected at approximately 22 kV and above, as well as customers connected directly to the transmission system.
According to the impact analysis by the Czech Energy Regulatory Office (ERÚ), the reform affects approximately 25,500 market participants, including electricity consumers and producers as well as operators of local distribution systems.
In practice, this includes many medium-sized and large industrial operations: manufacturing and processing plants, food production facilities, refrigerated and frozen warehouses, data centres, large logistics sites and facilities with their own substations.
Households and small low-voltage customers are not affected by this phase of the reform.
3. Do we have to choose between tariff T1 and T2?
No. The choice is automatic.
The new structure introduces two tariffs: T1 places greater weight on reserved input capacity, while T2 places greater weight on maximum 15-minute demand. At the end of each month, the distribution system operator calculates both alternatives and automatically bills the lower of the two.
That may sound like a safeguard, but there is an important distinction: “lower” means the lower of the two new tariff calculations — not the lower of the old and new system.
Under both tariffs, peak demand matters; the difference is how heavily it is weighted. And the applicable tariff is determined retrospectively according to your site's actual demand profile. The only way to influence the result is therefore to influence how your operation consumes electricity.
More importantly, where are most industrial sites likely to end up?
The dividing line between the two tariffs is approximately 80% utilisation of reserved input capacity. Below this level, T2 applies; above it, T1 applies. According to ERÚ data, the average customer uses only around 40% of its reserved input capacity. This means that the vast majority are likely to be billed under T2 — the tariff under which one megawatt of maximum 15-minute demand carries ten times the weight of one megawatt of reserved input capacity.
That, in one sentence, is the essence of the reform.
4. Does this mean we will pay more?
Not necessarily.
The reform is designed to be revenue-neutral overall: distribution system operators should not collect more revenue in total than under the current system. Instead, the costs will be distributed differently among customers.
According to ERÚ's impact analysis, the change should be positive for more than half of customers, with most impacts falling between approximately −30% and +20% compared with current distribution charges.
One factor is particularly important: how effectively you use your reserved input capacity.
If your contracted capacity is significantly higher than your actual peak demand, you will effectively be paying for capacity you do not use. On the other hand, if your site experiences one exceptionally high demand peak during the month, that single 15-minute interval can affect your charge for the entire month.
There is also another consequence that finance departments in particular need to consider: distribution charges will become more variable from month to month.
Where companies previously worked with a relatively stable cost item, part of the distribution charge will now be driven directly by operational behaviour. That has implications not only for energy management, but also for budgeting, forecasting and potentially pricing.
5. When will we receive the first invoice under the new rules?
In February or March 2027, depending on your billing cycle. It will cover electricity distribution in January 2027.
This has an important implication for your implementation timeline: whatever happens in your operation in January 2027 cannot be fixed retrospectively.
If you want the first invoice under the new tariff structure to be under control, your measures need to be implemented, tested and fine-tuned by December 2026.
6. Can't we simply reduce our reserved input capacity?
You can reduce it, and ERÚ actually recommends reviewing how effectively your reserved input capacity is being used and, based on the results, discussing an adjustment to your grid connection agreement with your distribution system operator.
But reducing it without proper analysis can be an expensive mistake.
Exceeding your reserved input capacity is charged separately each month, based on every kilowatt of the highest exceedance. At HV level, the charge can amount to hundreds of Czech crowns per kW. A single 15-minute interval in which your site exceeds the limit by 200 kW can therefore result in an additional charge running into hundreds of thousands of CZK.
It is also a long-term decision. Reserved input capacity forms part of the grid connection agreement and is linked to the technical parameters of the delivery point. Unlike the current reserved capacity, it is not something you simply adjust every month.
The correct sequence is therefore:
First get your peaks under control. Then consider reducing your reserved input capacity. Not the other way around.
7. Is monitoring the main billing meter enough?
For checking your electricity bill, yes. For actively managing and optimising costs under the new tariff structure, no.
Your main meter can tell you that a peak of Y kW occurred during a particular 15-minute interval. It cannot tell you which loads caused it.
And without that information, you cannot optimise the operation — you can only record what has already happened.
Submetering individual production lines, halls or major technologies allows you to identify the actual cause:
“During that 15-minute interval, compressor 3 started at the same time as the cooling system in warehouse B. We need to prevent that combination from occurring again.”
That is why submetering is the first phase of most energy optimisation projects rather than an optional add-on.
In addition to measurement, we recommend using reliable demand forecasting. It can help the control system safely reduce or shift consumption when a peak-demand event is predicted.
8. Isn't there a simpler way to control 15-minute maximum demand?
There are three assumptions we encounter particularly often — and each has a significant limitation.
“We'll manage it manually.”
In practice, this is extremely difficult. Fifteen minutes is a very short period in which to detect a rising trend, decide what to do and intervene. And these intervals occur almost 3,000 times every month, including nights and weekends.
“We have a diesel generator.”
A diesel generator typically takes several minutes to start and ramp up, which can be too slow within a 15-minute control interval. In addition, using diesel generators in this way is environmentally undesirable and often economically inefficient.
“Our solar PV will cover it.”
Solar PV cannot guarantee output exactly when you need it. In many industrial sites, the highest peak occurs during morning start-up, when PV generation is still low. Solar PV can be an excellent investment, but on its own it is not a reliable tool for controlling maximum 15-minute demand.
9. When does battery storage make sense, and how large does it need to be?
Battery energy storage is particularly useful for peaks that cannot be shifted or delayed — production cannot wait, cooling has to run, compressors need to maintain pressure.
The objective is not necessarily to reduce total energy consumption. It is to flatten the demand profile and reduce peak power demand.
And the battery does not necessarily have to be large. You do not need enough storage to cover the site's entire electricity demand — only the portion of the peak you want to shave.
Illustrative example
Peak demand reaches 600 kW and you want to keep maximum 15-minute demand below 450 kW.
You therefore need to shave approximately 150 kW from the peak.
If demand above this threshold typically lasts for around one hour per day during morning start-up:
Power: approx. 150 kW
With headroom for losses and degradation: approx. 165–180 kW
Usable energy capacity: approx. 150 kWh
Equivalent installed capacity: approximately 180–200 kWh
This is an illustrative example. Accurate battery sizing requires an analysis of your 15-minute load profile, ideally covering a full year to account for seasonal effects.
The economics have also improved from two directions: battery storage prices have fallen significantly over the past three years, while under tariff T2 every kilowatt shaved from the maximum demand directly affects the distribution charge.
10. What should we do now — and can we still make it before January 2027?
Yes, but the implementation window is getting shorter. The process is broadly similar for most industrial sites:
- Establish your baseline. Download 15-minute consumption data for at least the past 12 months from your distribution system operator or energy management system. Identify the highest 15-minute demand in each month and model the financial impact using the ERÚ calculator.
- Identify the sources of your peaks. Check whether sufficient submetering is already in place. Look for recurring patterns and combinations of loads that cause peak demand.
- Select the right measures. There are four main levers: submetering, real-time 15-minute maximum-demand control, predictive scheduling of major loads and energy storage. For most industrial sites, a combination delivers the greatest value because the real savings come from integrating these measures.
- Plan implementation. Make sure the solution is not only installed but also tested and fine-tuned before the new tariff structure takes effect.
If you do not have sufficient in-house expertise, consult an experienced energy management specialist who can analyse your demand profile and recommend the appropriate measures.
Or talk to us. We perform these analyses quickly and with the technical expertise needed to turn consumption data into actionable measures.