We often talk about electricity and less of thermal energy, that is, that part of the energy intended for the production of heat and cold. Yet the main item of final energy consumption is precisely that of thermal consumption. Obviously we are inclined to connect the idea of energy to light and the operation of appliances, but in this way we risk having a partial view of the subject.
In Italy, in 2011, the consumption of thermal energy they were about 55 thousand ktoe, equal to 55% of total final energy consumption. They were more than double those of electricity (23 thousand ktoe, corresponding to 21% of the total final). Incidentally, the energy absorbed by electricity consumption was also much less than that consumed by transport (34% of final consumption).
What are the sources ofthermal energy? Today the prevailing one is natural gas which covers over 63% of consumption, followed by petroleum products (diesel, LPG, fuel oils…) with 17%. Solid fuels (coal) account for about 6% while consumption from derived heat (cogeneration and district heating networks) for just under 6%. The consumption of renewable energy for thermal uses weighs over 7% (excluding the consumption of renewable energy from heat pumps).
The consumption characteristic of thermal energy is that they occur for the most part through appliances or plants for the production of heat that the users are equipped with and not directly, through a network distribution, as is the case with electricity or fuel. This also applies to methane gas which, despite being distributed by a network, owes its actual use to the combustion system with which the user is equipped.
Over the past 20 years in Italy, the consumption of thermal energy 46% depended on the residential sector (2011 data), 35% on the industrial sector, 15% on the tertiary sector and 4% on agriculture. In the residential sector, the use of natural gas is prevalent (71%) followed by renewables (14%). In agriculture, on the other hand, the use of petroleum products prevails (92%).
Renewables are increasing. Also in the last 20 years in Italy, consumption of thermal energy from renewable sources have more than quintupled from around 1,000 ktoe to 5,000 ktoe. In 2011 these consumptions were covered for about 70% by biomass, for 24% by heat pumps, for about 2.5% by solar thermal and geothermal energy.
(Istat data on Friends of the Earth processing)