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Introduction
The project
concerns the use of biomass deriving from urban activities and agricultural and
forest residues for the production of thermal energy in a new residential area
on the Venice Mainland (Mestre). It deals with the installation of a new
Thermal Energy Power Plant powered by “lignocellulose biomass”, and the
completion of a related sunken district heating system to provide a new
residential area with winter heating (teleheating) and summer
conditioning (telecooling) without the use of fossil fuels and without
any CO2 emissions.
This system will serve seven high-rise buildings in the
Bissuola district (Mestre, Venice’s Mainland), that are at the
moment under construction. The new lodgings have been financed by public funds
and they count about 100 flats for a total volume of 41,000 m3 and for 300 inhabitants.
The main peculiarity lies in the fuel chosen to feed the
thermal plant, and its life cycle analysis. When the project is completed,
about 3,246,000 kWh/year ([1]) will be provided by “lignocellulose biomass”.
This fuel is derived from renewable resources and will replace a part, even
though only very little for now, of non-renewable resources traditionally used
to satisfy city energy demand. This is not such an unusual practice in other
European countries, but its application in a coastal region, such as the Venice Mainland, has to be considered the
first example of its kind in Italy ([2]).
District teleheating and telecooling systems
Another peculiarity lies in the integration of
the district heating system with
the conditioning one. At first, the project was conceived and
structured only to be a district heating system. Afterwards, the project was
re-designed with a further technological innovation: the addition of a district
conditioning system (still benefiting from the same type of biomass) which
makes use of the “cooling absorption units” technology. This has a great
demonstrative value, since it seems to be one of the first examples in Europe.
The technical reasons for this further
development are:
- a rising trend in the
use of air-conditioning systems during the summer, especially in residential
areas, not only because of the higher temperatures recorded over recent years,
but also because of the higher quality of life that people increasingly demand that
leads to their expecting a home air- conditioning system;
- the need to use local
and renewable energy resources not only for the heating systems but also for
the conditioning ones, considering the recorded shift in energy consumption’s
peak values from the winter to the summer season.
Other economic incentives are:
- the awareness that
technological innovations in new lodgings is less expensive in an early phase
of planning and consruction than later on (when the buildings have been
completed);
- the cost of accomplishing
one district conditioning system for the whole 100- flats block (in spite of
its advanced technology) is comparable to the total cost of 100 traditional
conditioning systems ([3]);
- operating costs are
slashed by about 50% (considering energy costs of one traditional
air-conditioning system) or much more if we consider that the biomass has no
costs or negative costs (i.e. the additional cost for disposal).
The Mestre Wood
Another interesting aspect of this pilot project lies in
the origin of the “lignocellulose biomass”. The amount of biomass needed by the thermal energy plant
will be provided by the agricultural and forest sector (the Mestre Wood in primis) and by urban activities (selected
waste-material collection, tree pruning, etc.)
easily available in the Mestre and Marghera conurbations. The Mestre Wood is a large parcel of urban area where an intensive forestation
and reforestation program has been supervised by local Public Administrations:
they aim to provide Mestre with the largest peri-urban wood in Europe (see its future set-up in the map 1,
map 2
and map 3). Thanks to this project, the Mestre Wood will have a dual purpose: as a sink for CO2
emissions originating from urban sources (urban traffic, Porto Marghera
industrial site) and as a “fuel provider” thanks to by-products collected from
its ordinary maintenance.
Since the Mestre Wood will be completed only
in several years, the lack of biomass for the Thermal Energy Plant will be
solved by the collection of waste from tree pruning and from public- and
private-garden maintenance in the urban area. Thanks to this project, the disposal
of this waste will no longer be a financial burden and it will be used to
provide energy for the City itself. This was one of the most relevant aims
described in the Municipal
Energy Plan, recently approved by the City Council.--
([1])
This energy amount will satisfy the needs of winter heating, summer
conditioning and sanitary fittings for the whole block of council housing.
([2]) Usually forest residues
are used for heating systems in mountain regions.
([3]) About € 200.000,00 in the first case, €
150.000,00 in the second one.
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