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Greenbyte Documentation

Reliability Index (IA) and Compensated IA Signals

In the Italian energy market, the Reliability Index (Italian Indice di affidabilitá or IA) is a score (0%–100%) calculated per site (grid meter in the platform) based on how close the site is following curtailment order (requests) from the grid operator/owner. A high score yields more compensation for lost production due to curtailment than a low score.

This is the basis for calculating Compensated Lost Production (IA) and Compensated Lost Revenue (IA) for grid meters.

Technology

Wind

Note

Available only in Italy on grid meters.

Remarks

The following diagram shows how incoming curtailment orders are handled when calculating the reliability index:

Reliability_Index__IA__and_Compensated_IA_Signals_-_Remarks.png
Equations
Reliability_Index__IA__and_Compensated_IA_Signals_-_Equation_1.png

Where:

LRcompensated,grid

is the Compensated Lost Revenue (IA) (€)

LPcompensated,grid

is the Compensated Lost Production (IA) (kWh)

PriceEuro

is the Pool price (€/MWh)

Plimit,CO

is the power limit of the Curtailment order for each timestep

PPunfiltered+

is all potential power values, clamped to the positive part

T

is the device resolution in hours

Reliability_Index__IA__and_Compensated_IA_Signals_-_Equation_2.png

Where:

IA

is the Reliability Index (IA)

A

is the exemption/deductible, corresponding to 10 dispatching orders each lasting 1 hour and relating to the reduction of the nominal power of the PU by half.

In particular:

A = 10*0.5*Pn if, s ≤ 10

A = 0 if, s > 10

The deductible can be applied only once, during the start-up phase application of the IA index.

PU

is the Production Unit/Site

Pn

it is the rated power of the PU.

s

is the progressive number of dispatching orders sent by Terna, except those where the request implies a disconnection of the production unit from the network/grid via UPDM (Peripheral Monitoring Unit) equipment.

k

it is the progressive index of the curtailment dispatching orders.

m

is the progressive index of quarters of an hour included in the k-th curtailment dispatching order.

Nk

is the number of quarters of an hour included in the k-th curtailment dispatching order.

P′k, m

is a power equal to:

PLk,m if, Pk,m ≤ (PLk,m + Ɛm)

PLk,m + PF (Pk,Ɛm − PLk,m) if, Pk,m > (PLk,m + Ɛm) for m < 3

Pk,m in all other cases

PLk,m

is the maximum power imposed/permitted in the m-th quarter of an hour during the k-th curtailment dispatching order. In cases of indirect disconnections, the values of PLk,m are set equal to predetermined reduction values set in the tele-detachment system.

Pk,m

is the average power actually fed in during the m-th quarter of an hour of the k-th curtailment dispatching order. This power is calculated by dividing the amount of electricity fed in and measured in that quarter of an hour by 0.25.

PF

is the penalty factor for late implementation, set at 150.

Ɛm

is the maximum tolerance allowed between the imposed/permitted maximum power (PLk,m) and the actual fed in and measured power (Pk,m), calculated according to the following formulas:

Ɛm = 0.05*PLk,m if PL ≥ 10MW

Ɛm = 0.5 if PL < 10MW

CC

is, among the last curtailment orders up to a maximum of 10, except those where the request implies a disconnection from the network/grid via UPDM (Peripheral Monitoring Unit), the number of orders involving a limitation that is not zero "correctly executed" and by those without any quarters of an hour useful for the IA calculation due to the application of the next article 5.2 (C0C).

C0C

is, among the last curtailment orders, up to a maximum of 10, except those where the request implies a disconnection from the network/grid via UPDM (Peripheral Monitoring Unit), the number of orders involving a limitation to zero "correctly executed" and the number of orders without any quarters of an hour useful for the IA calculation due to the application of the next article 5.2.

The different parts of this calculation are available as separate data signals to aid in understanding how the resulting score values are calculated:

Sub-calculation

Data Signal Name

Data Signal Id

Data Signal Unit/Group

Comment

A

Reliability Index (IA), A Deduction

5989

Other

Accumulated over the last 10 curtailment orders

P′k,m

Reliability Index (IA), Actual Power or Power Limit

5991

Power

Non-accumulated momentaneous values

PLk,m

Reliability Index (IA), Power Limit

5990

Power

Non-accumulated momentaneous values

Reliability_Index__IA__and_Compensated_IA_Signals_-_Sub-Calculation_1.png

Reliability Index (IA), Actual Power or Power Limit Sum

6017

Other

Accumulated over the last 10 curtailment orders

Reliability_Index__IA__and_Compensated_IA_Signals_-_Sub-Calculation_2.png

Reliability Index (IA), Power Limit Sum

6018

Other

Accumulated over the last 10 curtailment orders

C C

Reliability Index (IA), Number of Correctly Executed Orders (Above Zero)

5987

Other

Accumulated over the last 10 curtailment orders

C0C

Reliability Index (IA), Number of Correctly Executed Orders (Zero)

5988

Other

Accumulated over the last 10 curtailment orders

Inputs
Reliability_Index__IA__and_Compensated_IA_Signals_-_Inputs.png
Usage Example

This section will be updated later.