|Waste-to-energy plants (51% renewable)||61,054||62,463||79,783|
|Combustion of treatment plant biogas||5,593||4,294||5,985|
|Total renewable sources||139,900||138,490||149,304|
|Cogeneration operated as a service||138,508||153,222||80,873|
|Thermoelectric power stations||252,584||231,607||216,055|
|Waste-to-energy plants (49% non-renewable)||58,660||60,013||76,655|
|Total traditional sources||311,244||291,620||292,710|
The thermal energy produced from renewable sources increased by 7.8% in 2017 as a result of: (i) the higher energy produced by waste to energy plants, especially in Ferrara (+58% from 2015) as a result of the improvement works carried out (with consequent improvement of the environmental profile, as described in the chapter Air and soil protection) ; (ii) the increase in the production of thermal energy from cogeneration of the biogas produced in the Group’s treatment plants.
The share of energy produced decreased: (i) from cogeneration in service (-73,246 MWh), due to the exit of 4 plants from the company scope by the end of the contract period; (ii) from thermoelectric power stations (-15,552 MWh).
Overall net thermal energy produced by the Group plants, therefore, fell by 7.3% with a change in the mix in favour of energy from renewable sources, due to the above.
Thermal energy produced from renewable sources is equal to 21.3% of total thermal energy in 2017, rising compared with previous years. 37% derives from cogeneration, a high energy efficiency system. Together, the two categories represent 58.5% of electricity produced. 10.9% is energy recovered from waste-to-energy transformation for the share exceeding 51%.