Silla 2 waste-to-energy plant

Silla 2 is the waste-to-energy plant in Milan and is located in the north-west area, near the Figino district.

Waste-to-energy is a process which, through the combustion of residual waste from separate collection not subject to recycling (undifferentiated dry waste), is capable of producing electricity and hot water for heating buildings (district heating).

The Silla 2 waste thermoelectric power plant supplies heat for district heating to the western area of Milan (Gallaratese district), to the Rho-Pero exhibition center and to those users connected to the district heating network in the Municipalities of Pero and Rho. At full capacity, Silla 2 is able to provide heating to approximately 30.000 families and to generate electricity for the benefit of approximately 147.000 families.

In 2016, the plant's full operation made it possible to save around 87.000 TOE (tonnes of oil equivalent) and avoided the emission of around 305.000 tonnes of carbon dioxide.

The facility is continuously open to visits by citizens, schools, associations and delegations.

Certifications

The most reliable and innovative technologies were adopted in the design and construction of the plant, to guarantee maximum environmental protection in relation to atmospheric emissions, noise, liquid discharges and solid residues.

The Integrated Environmental Authorization (A.I.A.) has set maximum limits on emissions, which are significantly lower than the limits established by Italian and European law. The emissions detected at the chimney of the Silla 2 waste-to-energy plant are widely and consistently below the limits indicated in the A.I.A.

The plant has obtained the following certifications:

ISO 14001 and EMAS (Environment)
ISO 9001 (Quality)
OHSAS 18001 (Safety)
ISO 50001 (Energy Management).

Monitoring

Silla 2's atmospheric emissions are monitored 24 hours a day by extremely advanced systems.

The monitoring activities of emissions into the atmosphere are carried out by multiple subjects, to guarantee effectiveness and impartiality:

direct and continuous monitoring of the three lines by A2A Ambiente through the control center inside the plant, controlled by the regional Agency for Environmental Protection (ARPA)
periodic analyzes carried out by certified external laboratories and by the Regional Environmental Protection Agency (ARPA).

Furthermore, the Scientific Technical Committee (CTS), a body made up of technicians appointed by the Municipalities that signed the Memorandum of Understanding, regularly receives all the data on emissions into the atmosphere in order to be able to carry out all the appropriate checks.

Measurements
The emission values relating to:

Hydrochloric Acid (HCI)
Ammonia (NH3)
Total Organic Carbon (TOC)
Carbon Monoxide (CO)
Nitrogen Oxide (NOx)
Sulfur Oxide (SOx)
Total dust (PTS).

On a quarterly basis, further sampling is carried out to determine:

Dioxins and furans (PCDD+PCDF)
Polycyclic aromatic hydrocarbons (PAHs)
Polychlorinated biphenyls (PCBs)
PM 10 and PM 2,5 dust
Cadmium and Thallium (Cd + Tl)
Mercury (Hg)
Nickel (Ni)
Zinc (Zn)
Sum of Metals (Sb+As+Pb+Cr+Co+Cu+Mn+Ni+V+Sn).

For PCDD+PCDF, IPA and PCB, long-term sampling is also active on a monthly basis.

Consult the data
The average daily data on emissions from the waste-to-energy plant can be consulted:

on the dedicated page of A2A >>
on the display located outside the system.

They are then made periodically available on this page in the section Attachments.

The memorandum of understanding

To guarantee the operation and environmental monitoring, in 2001 - the year Silla 2 came into operation - and subsequently in 2005 and 2009, memoranda of understanding were signed between:

Lombardy region
Province of Milan (now Metropolitan City)
the Municipalities of Milan, Cornaredo, Pero, Rho and Settimo Milanese
the owner and manager of the Silla 2 plant (formerly Amsa and now A2A Ambiente).

Thanks also to the commitments made with the signing of the aforementioned Protocols, transparency and access to data were guaranteed, the performance of the plant was improved and environmental improvement interventions were carried out.

In 2017, the Municipality of Milan approved the new Memorandum of Understanding which provides for a deadline of 31 December 2025. The new agreement reconfirms the role of the Scientific Technical Committee (CTS) as a monitoring body composed of technicians appointed by the signatory Municipalities, with the task of acquiring and verifying the operation of the plant, its detection systems as well as compliance with the maximum environmental protection requirements. Representative in the CTS for the Municipality of Milan is Dr. Bruno Villavecchia, Director of Environment and Energy of Amat, the Environment and Territory Mobility Agency.

The commitment to finance an environmental monitoring plan created, like the previous ones, by ARPA with the possible collaboration of a further technical body was also renewed. Furthermore, the activity implemented in recent years for the renewal of the vehicle fleet intended for waste transport will continue, with attention to the use of ecological vehicles and fuels.

As a continuation of the environmental improvement works financed in recent years (reforestation activities in the Southern Milan Agricultural Park and creation of cycle paths serving the Fontanili Park, the Figino district and the Bosco area in the city), A2A undertakes to finance interventions to redevelop the former nomad camp area adjacent to the Silla 2 plant, as well as carry out a faunal study and complete additional cycle and pedestrian paths for the connection with Molino Dorino.

As part of the CTS activities, the Municipality of Milan is committed to periodically holding information meetings for citizens, and in this regard, a collaboration has been started with Municipalities 7 and 8 to extend the communication activity on Silla 2 to the territory.

The story of Silla 2

Amsa (then SPAI - Servizi Pubblici Anonima Italiana) built the first waste incinerator in Milan in via Zama, in 1968, distinguishing itself as the first company in Italy to adopt waste-to-energy to produce energy from waste, and in 1975 it built a second plant in via Silla.

In the following twenty years the two plants were modernized but the entire management system of the waste produced in Milan was still based almost entirely on landfill.

The serious "waste emergency" of 1995 demonstrated the unsustainability of this system and imposed the need to find new solutions to the problem of waste disposal in the city of Milan.

In 1996 the tender for the construction of Silla 2 was announced and in 2001 the new power plant entered service, replacing the two previous plants.

The Silla 2 waste-fired thermoelectric power plant was designed with the aim of supporting, in the long term, the development of district heating in the metropolitan area of Milan while allowing the non-usefully recyclable urban waste produced by the city to be treated in a sustainable way.

In 2003, Silla 2 won, in its first edition, the Gold Medal of Italian Architecture award for private clients, awarded by the Milan Triennale. The system was in fact designed to guarantee maximum protection of the environment, without neglecting to ensure a harmonious architectural fit with the surrounding landscape.

One of the most curious aspects of Silla 2 is its chimney, 120 meters high and covered with a photochromic material that allows its color to change together with that of the sky.