Electricity transmission

During 2010, the overall amount of electricity injected into ACEA Distribuzione’s network (from the national transmission grid, generating plants that are directly linked to ACEA Distribuzione’s network and from ENEL Distribuzione’s interconnected network) decreased by 0.69% compared to the same period last year1. This average change is lower than the trend-based one established in the 2010 budget, estimated at +0.24% (deviation determined by comparing the estimated figure in the 2010 budget for energy injected into the network with the same figure provided at the end of 2009).

Peak demand on Acea Distribuzione’s network during 2010 amounted to 2,398 MW, which was recorded at 1.00 pm on 20 July 2010. This is up approximately 141 MW, or +6.25%, on the peak of 2,257 MW recorded in the same period last year, at 1.00 pm on 17 July 2009.

Electricity demand recorded on Acea Distribuzione’s network in 2010 was mildly affected by harsher weather conditions (with deviations in the reference temperature, TDR2, peaking in May, of -2.92°C, and September -2.65°C) and a higher number of working days (five more working days than the last calendar year3).

Weather conditions and the calendar clearly had an impact in March and April, in which electricity demand recorded increases of 2.03% and 1.40% respectively, in response to colder temperatures. By contrast, in May and June, mild temperatures led to a fall in electricity demand of 5.06% and 2.05% respectively.

July and August were characterised by contrasting weather conditions, which saw temperatures alternate from the highest in July (with an average variation of +5.13%) and the mildest temperatures in August (with an average variation of -5.87%).

The remainder of the year was characterised by moderate weather conditions in September, October and November (followed by reductions in electricity demand of -4.07%, -2.39% and -0.17% respectively). The weather got partially worse in December, with a subsequent increase in electricity demand of 2.77% (an increase also aided by the effects of the calendar). 

The graph below shows the trend in the reference temperature recorded in 2010 and the average monthly difference of said parameter calculated in the corresponding months of 2009 and 2010.

TDR change

The following table shows the monthly percentage variations of electricity injected into ACEA Distribuzione’s network, which were calculated on the basis of the volumes recorded in 2009 and 2010, as recorded by the related metering system (raw series) and as resulting from the calculations4 made in order to counterbalance the effects of the said weather conditions and the different calendar days (purified series):

2010 Vs. 2009 Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Total
"RAW” SERIES -0.76% 0.33% 2.03% 1.40% -5.06% -2.05% 5.13% -5.87% -4.07% -2.39% -0.17% 2.77% -0.69%
"PURIFIED" SERIES -0.41% -0.09% -0.08% -0.11% -2.62% -1.41% 3.30% -2.48% 2.86% -0.73% -0.55% 0.87% -0.10%

The following table shows the monthly sequence of electricity injected into ACEA Distribuzione’s network during 2010, together with the same series for 2009:

2010 Vs. 2009 Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Total
2010 1,043.70 953.76 995.44 893.22 919.74 972.59 1,196.37 969.21 971.48 960.87 970.03 1,054.31 11,900.72
2009 1,051.71 950.64 975.65 880.85 968.78 992.92 1,137.95 1,029.66 1,012.70 984.41 971.67 1,025.92 11,982.86

These electricity amounts were intended to cover the needs of the utilities supplied by the above-mentioned network, i.e. the customers of the free and protected markets and of the market subject to additional safeguards, as well as the so-called underlying distributors, which are represented by the electricity company of the Municipality of Saracinesco.

There are also sales and injections of energy between the ACEA Distribuzione’s network and ENEL Distribuzione’s networks at some LV, MV and HV interconnection points.

With regard to FY 2010 and as compared to 2009, the following table illustrates the above-mentioned aspects, with further specification of the contribution given by Acquirente Unico S.p.A. and by the import supply:

  Market subject to additional safeguards Free market Underlying distributors Total
 AU Source Other Sources

 GWh GWh GWh GWh GWh
2010 4,117.32 432.38 7,348.17 2.85 11,900.72
2009 4,485.52 432.38 7,062.25 2.71 11,982.86

With regard to import supply, as from 1 January 2002 ACEA Distribuzione signed an agreement with the Vatican City State (that was renewed on 6 July 2006) in force from 1 January 2007 to 31 December 2011, for the optimised management of imported electricity assigned to it (established by Terna, in accordance with the indications provided by the Italian Authority for Electricity and Gas, based on the Decree issued by the Ministry for Productive Activities – now the Ministry for Economic Development - that sets out the assignment of transmission capacity shares to the interconnection with foreign countries for the Vatican City State and the Republic of San Marino).

In this context, the Company undertook to provide technical services linked to the management of underlying utilities to the above-mentioned State, as well as to rationalise and improve any related electricity network and plant.


1 Data provided at the end of 2009.
2 The reference temperature (TDR) is defined as the weighted average of the daily temperature highs and lows which better reflects the effect of the weather on electricity demand. The reference temperature trend shown in this report was drawn up on the basis of updates to historical series’ carried out following the drafting at the end of the half in 2010.
3 The calendar is assessed by counting the number of weekdays, holidays and pre-holidays distributed throughout the year.
4 Energy figures which discount the impact of the weather and the calendar were calculated by using de-climatisation, de-calendarisation and de-seasonalisation parameters updated after the close of the half in 2010.