Description of the calculations used to determine electricity generation
efficiency
calculation 1
efficiency (thermoelectric) =
Energythermoelectric (kWh)
Energydiesel oil (kWh) + Energynatural gas (kWh)
where:
Energythermoelectric = gross electricity produced using thermoelectric cycle
Energydiesel oil (kWh) =
Energynatural gas (kWh) =
diesel oil (l) • 0.835 • NCVd (kcal/kg)
860 (kcal/kWh)
natural gas (Nm3) • NCVm (kcal/Nm3)
860 (kcal/kWh)
NCVm = 8,500 kCal/Nm3 (net calorific value of natural gas)
NCVd = 10,000 kCal/kg (net calorific value of diesel oil)
860 = energy conversion factor from kcal to kWh
0.835 = specific weight of diesel oil (kg/l)
Energy equivalent
to diesel oil consumed (95)
Energy equivalent
to natural gas consumed (93)
NB: between 2010 - 2012, the calorific values used for Acea Produzione were the effective ones taken from the gaugings of the natural gas and diesel oil
suppliers
calculation 2
efficiency (thermoelectric) =
Energythermoelectric (kWh) + Energy thermal (kWh)
Energydiesel oil (kWh) + Energy natural gas (kWh)
where:
Energythermal = Gross thermal energy produced
Energythermoelectric = Gross thermoelectric energy produced
Energydiesel oil (kWh) =
Energynatural gas (kWh) =
diesel oil (l) • 0.835 • NCVd (kcal/kg)
860 (kcal/kWh)
natural gas (Nm3) • NCVn (kcal/Nm3)
860 (kcal/kWh)
NCVn = 8,500 kcal/Nm3 (net calorific value of natural gas)
NCVd = 10,000 kcal/kg (net calorific value of diesel oil)
860 = energy conversion factor from kcal to kWh
0.835 = specific weight of diesel oil (kg/l)
Energy equivalent
to diesel oil consumed (95)
Energy equivalent
to natural gas consumed (93)
NB: the calorific values used for Acea Produzione were the effective ones taken from the gaugings of the gas and diesel oil suppliers
Environmental accounts 2012
251
calculation 3
Energyhydroelectric (MWh) • 3.6 • 109
efficiency (hydroelectric) =
[m(kg) • 9.8(m/s2) • h(m)] (joule)
where:
3.6 x109
= water energy conversion factor from Joules to MWh
m
= offtake water for hydroelectric production
9.8 = gravitation acceleration at sea level
h
= height of water drop (free surface reservoir– turbine)
Energy hydroelectric = energy produced in the hydroelectric cycle
calculation 4
(Ei)
• ei +
(Ei + Et)
(Et)
(Ei + Et)
• et = eaverage
where:
Ei = total hydroelectricity produced
Et = total thermoelectricity produced
Єet = thermoelectric efficiency
eЄi = hydroelectric efficiency
eaverage = average production efficiency
calculation 5
(Ei)
• ei +
(Ei + Et)
(Et)
(Ei + Et)
• et = eaverage
where:
Ei Et eЄi Єet
eaverage 252
= total hydroelectricity produced
= sum of total energy (thermoelectric and thermal) produced
= hydroelectric efficiency
= efficiency (thermoelectric + thermal)
= average production efficiency
Environmental accounts 2012
calculation 6
(
recovery efficiency =
kWh
kg
)=
Gross electricity produced (kWh)
CDR (kg)
Energygross electricity produced (kWh) = Gross electricity produced at S. Vittore = (item 12)
calculation 7
electric efficiency (%) =
Net electricity produced (kWh)
WDF internal energy (kWh) + Natural gas internal energy (kWh)
where:
Net electricity produced at S. Vittore (item 12 - internal consumptions)
Natural gas internal energy =
Natural gas Sm3 • NCVn (kcal/Sm3)
860 (kcal/kWh)
NCVn = about 8,500 kCal/Sm3 (net calorific value of natural gas)
860 = energy conversion factor from kcal to kWh
WDF internal energy (kWh) =
WDF (kg) • NCVw (kcal/kg)
860 (kcal/kWh)
NCVw
= 3,583 kCal/kg (15,000 kJ/kg) – WDF average net calorific value
860 = energy conversion factor from kCal to kWh
Environmental accounts 2012
253
calculation 8
(
recovery efficiency =
kWh
kg
)=
Gross electricity produced (kWh) at Terni
pulper (kg)
Gross electricity produced at Terni (kWh) = (item 13)
calculation 9
Net electricity produced (kWh)
electric efficiency (%) =
pulper internal energy (kWh) + Natural gas internal energy (kWh)
where:
Net electricity produced at Terni (item 13 – internal consumptions)
Natural gas internal energy =
860 (kcal/kWh)
NCVn = about 8,500 kCal/Sm3 (net calorific value of natural gas)
860 = energy conversion factor from kCal to kWh
Pulper internal energy (kWh) =
254
Natural gas (Sm3) x NCVn(kCal/Sm3)
pulper (kg) • NCVp (kcal/kg)
860 (kcal/kWh)
NCVp
= 3,635 kCal/kg 15,216 kJ/kg) - Pulper average net calorific value (year 2010)
860 = energy conversion factor from kCal to kWh
Environmental accounts 2012