Italy's Testo Integrato del Dispacciamento Elettrico (TIDE) changes how production, consumption and storage resources participate in dispatching. For a distributed-flexibility project, the first design question is not which meter to install. It is which market unit contains the site, which party carries each responsibility and which record Terna will use to assess delivery.
The current rules distinguish nodal and zonal aggregation, the energy position and the balancing service, and operational telemetry from market settlement. A building or industrial site can support the operational evidence chain, but its local meter is not automatically Terna's approved measurement or control interface.
The consolidation phase is now in force
TIDE entered into force on 1 January 2025 through staged implementation. The simplified transitional phase ran until 31 January 2026. The consolidation phase began on 1 February 2026.
ARERA Resolution 566/2025/R/eel describes consolidation as an almost complete implementation of TIDE. It identifies exceptions, including the complete market procurement of Frequency Containment Reserve (FCR) and the separation of BSP and BRP roles for plants essential to system security. It also records implementation work that could continue through later Grid Code updates.
Terna's public TIDE explainer describes a third, final regime after 31 December 2026. The later ARERA decision is more precise about its legal start: the final regime begins on a date that Terna will identify subsequently. Do not treat 1 January 2027 as a confirmed switch date unless a current ARERA or Terna instrument has set it.
As at 6 October 2026, the operative planning basis is therefore the consolidation phase and the current Grid Code. ARERA Resolution 339/2026/R/eel, published on 2 October 2026, verified proposed Code changes for UVAZ participation in the PICASSO platform. That decision should trigger a check of the implemented Code and operator notices. It should not be converted into an assumed go-live date in a site specification.
BRP and BSP are different responsibilities
TIDE separates the commercial energy position from delivery of an ancillary service.
| Role | Responsibility under the TIDE structure | Site information it needs |
|---|---|---|
| Balance Responsible Party (BRP) | Manages nominations and the energy position, and carries the resulting imbalance responsibility | The site's expected production or consumption and any changes that affect the nominated position |
| Balancing Service Provider (BSP) | Qualifies eligible units, submits ancillary-service offers and is responsible for accepted balancing or redispatch movements | Available upward and downward flexibility, service limits, current state, dispatch acknowledgement and delivered response |
| Asset owner or operator | Runs the equipment within connection, safety, process and contractual limits | Local measurements, equipment state, operating constraints, set-point ownership and override status |
| Terna | Operates national dispatching, applies the Grid Code, receives market and control-system information and settles the relevant movements | Nominations, offers, baseline where required, approved measurements and the service-specific data path |
The same company can perform more than one role, but the records remain distinct. A BSP instruction can change physical power and create a deviation from the BRP's energy position. The contracts and settlement process determine how that effect is handled. A site controller should not infer the BRP's schedule or settlement position from a dispatch message alone.
The consolidation phase separated BRP and BSP for most resources. Essential plants remain a stated exception while the relevant arrangements are completed. Confirm the contracts for the exact unit rather than applying the general separation to every plant.
UVAN is nodal and UVAZ is zonal
Terna's current Chapter 4 uses two enabled virtual-unit structures for aggregation.
UVAN
An Unità Virtuale Abilitata Nodale (UVAN) can aggregate eligible production units (UP) and consumption units (UC) for redispatch and for balancing services whose technical requirements it meets. The resources must be connected or attributable to one relevant transmission node, or to neighbouring nodes that Terna accepts as having similar sensitivity on the surrounding network. One BSP manages the aggregation.
This nodal boundary matters because redispatch addresses network conditions as well as the national energy balance. Two sites in the same bidding zone do not automatically form one UVAN. Where different neighbouring nodes are proposed, Terna validates the perimeter.
UVAZ
An Unità Virtuale Abilitata Zonale (UVAZ) aggregates eligible UP and UC in one bidding zone for balancing services. Chapter 4 says that a UP included through this route must not relate to a storage resource under Legislative Decree 210/2021. It also excludes units already constituted as a UAS or UnAP or included in a UVAN. One BSP manages the aggregation.
The current Code also limits one UVAZ so that its resources, considered together, cannot modulate active power by more than 30 MW in absolute value. That is an upper aggregation boundary, not a promise that any smaller portfolio qualifies. Each requested service has its own technical requirements and minimum modulation capability, followed by Terna's qualification process.
A UVAZ must have validated aggregate measurement data with at least quarter-hour granularity, a continuously staffed physical control point and the devices needed to provide information to Terna's control systems under Annexes A.6 and A.81. These are BSP and market-interface duties. A separate building energy dashboard does not satisfy them by existing on the same site.
The baseline depends on the aggregation type
The Imbalance Settlement Period (ISP) is 15 minutes. Chapter 7 defines a different settlement baseline for each enabled-unit structure:
| Unit | Baseline used for settlement |
|---|---|
| UAS | The final nomination registered for that UAS for the ISP |
| UVAN | The sum of the final nominations of the UVN units beneath that UVAN for the ISP |
| UVAZ | The BSP's submitted aggregate baseline for the ISP, adjusted by the correction calculated by Terna |
For a UVAZ, Chapter 4 defines the submitted baseline as the BSP's best estimate of the total net power injected by the underlying points for each ISP. The BSP can communicate it between the opening of MB offer submission and 27 minutes before the ISP begins. If the baseline has not arrived by that deadline, the UVAZ is unavailable for balancing for that ISP.
The 27-minute value is easy to misuse. It is the deadline before the ISP for the UVAZ baseline. It is not the sampling interval for a meter, the response time for a balancing service, the duration of an event or permission to delay local action. Those requirements come from the relevant service, qualification and control-system rules.
Chapter 7 then corrects the submitted UVAZ baseline for settlement. The correction uses the difference between measured aggregate power and the submitted baseline in the closest previous consecutive ISPs that meet the stated condition: the absolute accepted net MBR quantity is below 0.5 MW. No more than eight previous ISPs are used. At 15 minutes each, that is at most two hours of eligible preceding intervals, although fewer intervals may qualify.
For an upward accepted quantity, the correction takes only a positive average deviation; for a downward accepted quantity, it takes only a negative average deviation. The authoritative calculation remains Terna's Chapter 7 settlement process.
Build three separate records
A useful site design keeps market, control and measurement records connected by identity and time, without treating them as interchangeable.
- Market record. Keep the unit identity, BSP, BRP, ISP, nomination or submitted baseline, offer, accepted quantity and Terna settlement result.
- Control record. Keep the request received by the site, its timestamp, acknowledgement, requested direction and magnitude, controlling system, local limit, override and final command sent to the asset.
- Measurement record. Keep power at the agreed boundary, asset power where separately metered, timestamp, interval, unit, sign convention, validity and missing-data state.
Use one identifier for the event across all three records. Store both the time the instruction was issued and the time the asset changed power. Preserve a missing value as missing. A zero is a measured operating value and must not be substituted for a communication gap.
The operational and settlement metering guide explains why a site submeter and the official market record can legitimately differ. The site record diagnoses what happened inside the boundary. The approved market measurement and baseline determine the settled result.
Example of a site evidence chain
Consider a cold store included in an aggregation. Its normal import before an event is 620 kW. The BSP requests a 180 kW reduction for one 15-minute ISP. The refrigeration controller accepts a 150 kW limit because the room-temperature constraint blocks the last 30 kW.
The event record should show:
- the BSP request for 180 kW and the applicable ISP;
- the controller's accepted limit of 150 kW and the constraint that caused it;
- the measured power at the agreed site boundary throughout the interval;
- the compressor and temperature state used to explain the local response; and
- the return-to-normal sequence after the event.
The example does not establish market delivery by subtracting 150 kW from 620 kW. The accepted market quantity, relevant baseline, Terna correction and approved aggregate measurement still determine settlement. The operational record explains why the site delivered the measured response and why it could not safely provide more.
Keep local control inside the plant boundary
The BSP can request a change, but the site remains responsible for safe operation. Name the one system that owns each writable set point. Preserve equipment protection, connection limits, BMS interlocks, battery state-of-charge limits, process constraints and manual overrides.
For each dispatch path, record:
- who may arm or disarm participation;
- which system can write the active-power or load limit;
- the allowed range and rate of change;
- how the asset acknowledges the request;
- which measured point confirms delivery;
- what happens when communication is lost; and
- how the asset returns to its normal schedule without causing a rebound peak.
Use the local control interlock and failure matrix before enabling remote control. A market instruction must not bypass a protection or make two controllers compete for the same set point.
Where EpiSensor fits
EpiSensor can provide owner-side operational measurements and approved integration around flexible loads, generators and batteries. Electricity monitors can separate the flexible asset from unrelated site demand. A Gateway running Edge can retain timestamped interval data, equipment state, control requests and acknowledgements on site, and send approved data to the BSP's platform over MQTT or HTTPS.
Where local action is agreed, a demand response controller can shed a suitable load through a relay or pass an approved set point to compatible plant. The asset's own controller, protection and interlocks remain authoritative. The demand response solution shows this site-side pattern.
This site-side system does not qualify a UP or UC, create a UVAN or UVAZ, act as BRP or BSP, calculate Terna settlement or certify compliance with Annex A.6 or A.81. It must not be described as Terna's certified telemetry path unless the complete BSP design has been assessed and accepted under the current requirements.
Before procurement, obtain the BSP's written specification for the aggregation, service, measurement boundary, sign convention, sampling and reporting, control-system interface, availability process and event evidence. Then map each required point to the approved site interface. System Builder can support that equipment survey after the market and control boundaries are fixed.
Common questions
What changed on 1 February 2026 under TIDE?
Italy entered the TIDE consolidation phase. For most resources, the role responsible for energy schedules and imbalance, the BRP, can be separate from the BSP responsible for ancillary-service offers and delivery. ARERA describes this phase as an almost complete implementation, with specified exceptions and later steps still outstanding.
What is the difference between UVAN and UVAZ?
A UVAN is a nodal enabled virtual unit. It can combine eligible production and consumption units at one transmission node or at neighbouring nodes that Terna accepts as having similar network sensitivity. A UVAZ is a zonal enabled virtual unit whose eligible resources are in one bidding zone. Each aggregation has one BSP and must meet the technical rules for the service requested.
Who provides the baseline for an Italian flexibility aggregation?
For a UVAN, the settlement baseline is the sum of the final nominations of the underlying UVN units. For a UVAZ, the BSP communicates its best estimate of aggregate net power for each 15-minute ISP. Terna then applies the correction defined in Chapter 7 of the Grid Code for settlement.
Is the UVAZ baseline due 27 minutes after an instruction?
No. The current Chapter 4 deadline is 27 minutes before the start of the relevant ISP. It is a market baseline deadline, not a telemetry sampling rate, dispatch response time or allowance for local control. If the BSP misses it, the UVAZ is unavailable for balancing in that ISP.
Can EpiSensor qualify a site or supply certified Terna telemetry?
No. Qualification belongs to the BSP and Terna under the current TIDE and Grid Code process. Terna's required control-system path is governed by its technical documents, including Annexes A.6 and A.81. EpiSensor can provide separate owner-side operational measurement, local records and approved integration, but that must not be presented as the certified TSO interface or official settlement meter.