Green transition, the long march to 2050

Energy

A2A, how to meet the waste heat recovery challenge

The company led by Renato Mazzoncini has set up a series of initiatives in Bergamo, Milan and Brescia to make a concrete contribution to the decarbonisation of the country.

Laura Bonadies

14 October 2024

5' min read

Translated by AI

Versione italiana

5' min read

Translated by AI

Versione italiana

(Il Sole 24 Ore Radiocor) - In the long march towards decarbonisation by 2050, the recovery of waste heat can play an important role. A tool that is often not given the right weight among green solutions but that instead can represent a development lever for the country. One of the first in Italia to believe in it was A2A, which, through a series of initiatives based, on the one hand, on the district heating network and, on the other, on the recovery of heat from plants, companies and even data centres, has given rise to a series of projects that may one day become a model to be exported.

Bergamo, from the Rea Dalmine waste-to-energy plant new clean heat

The latest initiative put in place by A2A concerns the city of Bergamo. In September, in fact, an agreement was signed for the recovery of the heat generated by the Rea Dalmine waste-to-energy plant, enabling A2A to expand the district heating network in Bergamo without having to use fossil fuels. From next autumn, the Group will in fact be able to bring clean heat to the city, heating up to 11,000 more flats, thanks to the waste heat from the Rea Dalmine plant. With the new cogeneration set-up, which consists of a new turbine and a heat exchanger, for the same amount of waste treated, in addition to producing 95 thousand MWh of electricity per year, heat equal to90 thousand MWh of heat will be recovered, most of which is today dissipated into the atmosphere. This will increase the plant's energy conversion efficiency from 27% to over 80%.

Overall, the project entailed an investment of approximately 30 million euro, of which more than 20 million for the construction of the connection to the district heating network and for the works at the Goltara power station (storage and pumping system), the responsibility of A2A Calore e Servizi; and approximately 9.5 million for the construction of the new cogeneration section, the responsibility of Rea Dalmine. Today, Bergamo's district heating system extends over 87 kilometres, heats approximately 37 thousand equivalent flats and avoids the emission of 20 thousand tonnes of CO2 into the atmosphere.

In five years, A2A Calore e Servizi plans to extend the network by a further 22 kilometres, with environmental and economic benefits for households. Thanks to the recovery of heat from Rea Dalmine, 11,000 boilers will be turned off, eliminating the same amount of CO2 that a system of 25,000 photovoltaic panels would eliminate. The new district heating extension will reduce carbon dioxide emissions by about 15,000 tonnes per year.

In Milan, Italy's first project for data centre heat recovery

A2A's commitment to the process of decarbonisation is also demonstrated by the first project to recover heat from data centres in Milan: Retelit's "Avalon 3" data centre. This will make it possible to serve 1,250 more households a year, saving 1,300 tonnes of oil equivalent (TOE) and avoiding the emission of 3,300 tonnes of CO2 with environmental benefits equal to the contribution of 24,000 trees.

The project, in collaboration with Dba Group, envisages the construction of a plant, operational in the first months of 2026, thanks to which the waste heat from Retelit's Avalon 3 Data Centre - which with its over 3,500 square metres and 3.2 MW of power is the largest Internet interconnection point in Italia - will be fed into the district heating infrastructure managed by A2A Calore e Servizi, increasing the green energy available to households in the western area of the city. The facility will return 2.5 MWt of annual thermal power to the grid and an increase of 15 GWh of recoverable energy.

The Brescia environment-energy system

Completing the picture is the project implemented in Brescia, which was the first Italian city to equip itself with a district heating system. The network now covers 682 kilometres and serves 21,700 users (one user may involve several flats, as in condominiums). The volume heated in 2023 was approximately 43 million cubic metres, equal to almost 180 thousand equivalent flats connected, avoiding the emission ofmore than 115 thousand tonnes of Co2 into the atmosphere.

The heat required for the needs of Brescia's district heating network today comes mostly from non-fossil sources, primarily the waste heat generator, as well as waste heat from two steel mills (Ori Martin and Alfa Acciai) and from thermal storage (large hot water tanks for peak demand management). Tu's three lines generate more than 70 per cent of the heat distributed by the Brescia district heating network and electricity equal to the needs of 200,000 households. Numbers that save about 160 thousand tonnes of oil equivalent per year, avoiding the emission of 683 thousand tonnes of CO2 into the atmosphere (2023 figure). A virtuous process that has been further improved. In fact, at the end of 2023, the 'flue gas cleaning' project was completed: an investment of about EUR 110 million to make the thermal utiliser even more efficient and sustainable. Thanks to an innovative technology, it was also possible to recover the heat of the flue gases from the chimney, previously dispersed into the atmosphere, generating additional thermal energy for 12,500 households with the same amount of waste treated: in this way it was possible to further reduce the use of gas to feed the district heating network and the efficiency of the plant was brought close to 100% (from 84% to 98%). A new data centre will also be integrated into the system in the coming months, from which additional heat for district heating will be recovered: the pilot project is expected by the end of the year.

Teleriscaldamento, in Italia potential of 53 Twh

That waste heat recovery is strategic for achieving climate neutrality is also evidenced by the study conducted by A2A and The European House Ambrosetti and presented at the latest Cernobbio Forum. The position paper starts from the awareness that the game to achieve climate neutrality must be played above all in cities. In this context, the potential of district heating in Italia is estimated at 53 TWh, which is 4.4 times higher than the energy currently supplied, approximately 12 TWh. Looking specifically at the composition of the district heating potential supplied to users in Italy, it can be seen that 38% comes from high-temperature waste heat, 32% from geothermal energy, 32% from low-temperature waste heat, 2% from ambient heat, and 1% from solar thermal. The study emphasises that this potential in Italy's capital cities is approximately 9.7 TWh distributed as follows 37% in the North-West, 25% in the Centre, 21% in the North-East and 17% in the South and Islands. Fully exploiting this potential, equal to 81% of the district heating energy supplied today throughout Italia and 10% of the thermal consumption of cities, would make it possible to avoid the emission of 1.7 million tonnes of CO2, equal to about 3% of their total emissions