District heating is a service involving the sale of heat for customer home heating and domestic hot water. It is an alternative system to traditional boilers which makes it possible to concentrate the production of heat in just a few central installations, which are more efficient and better controlled than home boilers. From these central installations, the heat is distributed through a network of isolated pipelines into the homes of customers in the form of hot water. The heat then fuels the domestic heating system via non-polluting heat exchangers.
There are numerous customer benefits: increased safety (no gas), lower operating and maintenance costs (no domestic boiler) and the freedom to independently regulate the temperature of each housing unit.
For cities, district heating provides a solution to air pollution problems by replacing home boilers (frequently fuelled with gas-oil or methane) and allows heat generation from high-efficiency production methods, renewable energies, or energy recovered for other production processes.
| 2006 | 2007 | 2008 | |
|---|---|---|---|
| Primary energy saved (toe) | 15,808 | 12,558 | 13,097 |
| Nitric oxide avoided (t) | 101,7 | 81,1 | 72,0 |
| Carbon dioxide avoided (t) | 62,765 | 52,244 | 56,598 |
| Sulphur oxide avoided (t) | 137,1 | 123,8 | 136,2 |
Calculated as the difference between a traditional installation (heating installation 35% fuelled by gas oil and 65% by methane, with an average seasonable output of 75%, and an electricity power plant with average Italian emissions) and Hera’s district heating plants for the same quantity of energy (thermal and electricity). In 2008, the estimation coefficients for emissions were updated to conform with changes in the mechanisms from the Emission Trading regulation.
It is estimated that the installations managed by Hera led to primary energy savings equating to 13,097 tonnes of oil in 2008. Furthermore, district heating also makes it possible to avoid the atmospheric emission of polluting substances.
The total environmental benefits resulting from the use of district heating have been confirmed from the increase in emissions avoided, particularly sulphur oxide and carbon dioxide, as well as the increase in primary energy saved.
Environmental efficiency from co-generation in Imola
On 23 December 2008, the Mayor of Imola with Hera’s Chairman and the Managing Director “switched on” the plant’s new gas turbine, which has electric power of 73.2 MW and thermal power of 80 MW as part of a co-generation framework with recovery for district heating.
The overall efficiency of the plant is around 78%; normally performance is less than 50%. Better performance and long-term safety standards compared to the old Montericco plant: triple the amount of heat produced, a reduction of 34% of nitric oxides emitted (72 tonnes less per year) and lower CO2 emission of 48 tonnes per year, due to sophisticated, third-generation technology. The plant will comply with prescribed emissions limits due to the inclusion of specific abatement systems in the project. A further environmental benefit derives from the elimination of thousands of residential boilers, often obsolete, that with district heating will be replaced by zero-emissions heat exchangers.
| 2006 | 2007 | 2008 | |
|---|---|---|---|
| Thermal energy sold (MWh) | 425,850 | 391,501 | 422,633 |
| Volumes served (thousand of m3) | 14,798 | 15,301 | 16,109 |
| Housing unit equivalents served (No.) | 49,326 | 50,838 | 53,696 |
Housing unit equivalents served were calculated on the basis of an average apartment volume of 300 m3.
Thermal energy sold increased by 8% in the last year. This increase is due in equal parts to the increase in volumes served (+5%) and to a colder climate in 2008 compared to 2007.
The proposed development of district heating in the Industrial Plan is of considerable significance and envisages a substantial enhancement of the connected volumes, (an increase of 30% in volumes served by 2011 with respect to 2008 volumes).
More district heating in Forlì and Cesena
District heating implementation projects in the Forlì-Cesena area are increasing. In 2008 in Cesena, the Ippodromo co-generation plant was expanded, with connection to new areas that include provincial and municipal educational buildings; in Forlì, in addition to reaching new areas, preliminary work was performed to exploit heat generated from the local waste-to-energy plant. In the upcoming years, the investments made will result in a completed project that will also include the centre of Forlì. During 2008 the plants introduced into the network more than 19,000 MWh and buildings were connected for a total of 5100 kW. Within a decade, district heating will be standard, decreasing dependence on fossil sources (-51%) and reducing environmental impact because of lower CO2 emissions (72%), NOx (80%), CO (74%) and PM 10 (82%).
