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L. de Santoli et al. / Sustainable Energy Technologies and Assessments 8 (2014) 42–56 43

Nomenclature

a axial induction factor Abbreviations
area
A carbon intensity CFD computational fluid dynamic analysis
carbon dioxide savings amount
CI power coefficient EU European Union
electric energy
CO2sav operation hours EWEA European Wind Energy Association
Cp equivalent continuous A-weighted sound pressure level
E power GHG greenhouse gas emissions
sound pressure
h reference sound pressure HAWT horizontal-axis wind turbines
rotor power
LAeq wind turbine net electrical power IEA International Energy Agency
P time
exposure period IMED Italian Ministry of Economic Development
ps speed
ps0 inlet speed IMELS Italian Ministry for the Environment, Land and Sea
PT middle section speed
Pel Watt IUCN International Union for Conservation of Nature
t
LCA Life Cycle Assessment
T
PV photovoltaic system
U
VAWT vertical-axis wind turbine
Uin
Um WMO World Meteorological Organization
W
Greek symbol

gmecc wind turbine mechanical efficiency
gel wind turbine electrical efficiency
q density

DU difference in speed

installations number of small wind turbines. It is clear that this The main aim this research was to develop an eco-friendly
enhancement is not comparable to that of other countries, such energy production system for natural protected areas which was
as China, USA and other EU countries. For example, in England, in able to take advantage of winds at low speed. In particular, the
2012, 3715 small wind (0–100 kW) turbines were installed [7]. In research focused the attention on an innovative prototype verti-
Table 2, data related to the small wind turbines installations in cal-axis micro wind turbine. Moreover, in order to facilitate its
Italy during the last years were reported. installation in areas where the electrical grid is unavailable, the
AM300 was realized for both on-grid and off-grid applications
These energy devices are used all around the world in a wide (see Fig. 1).
range of applications and contexts such as in urban and residential
areas [9–11], in rural environments [12] and in isolated and remote In order to evaluate the energy potential production of the
areas [13]. Even though the contribution of wind energy source for AM300 prototype, a computational fluid dynamic analysis and
reducing greenhouse gas emissions and mitigating climate change in situ measurements were conducted. Furthermore, an environ-
is extensively recognized, there are not many scientific studies that mental impact assessment was realized starting from previous
analyze locally environmental pressures of small scale wind energy studies on environmental impacts analysis and mitigation tech-
devices on the surrounding areas. Furthermore, in a distributed niques in natural protected areas [20–21]. Finally, in order to
generation deployment context, micro wind turbines can be inter- emphasize the obtained energy results, an energy assessment
connected within smart grids in order to achieve a significant pri- and CO2 savings analysis in the Favignana island were realized.
mary energy saving and a reduction of greenhouse gas emissions
[14]. Moreover, effective storage systems are required to mitigate Methods: AM300 prototype description and energy issues
the mismatching between electrical needs and productions due
to the fact that it is not possible to exactly estimate the electrical Prototype description
production from wind energy source. The renewable hydrogen rep-
resents a viable clean storage solution which offers several applica- The wind turbine net electrical power (Pel) reads as:
tions such as hydrogen enriched natural gas blends (H2NG) and the
deferred load meeting by fuel cell integration [15–19]. Pel ¼ 1 q AU 3 C p gmecc gel ð1Þ
2
In this framework, this paper reports the preliminary energy
results and environmental impact assessment of a micro wind tur- where:
bine prototype, called AM300. This micro aerogenerator was real-
ized during a research project carried out by the Interdisciplinary gmecc is the wind turbine mechanical efficiency;
Centre for Landscape, Building, Conservation, Environment (CITER- gel is the wind turbine electrical efficiency;
A) of Sapienza University of Rome, with the collaboration of a pri- q is the air density;
vate company and the financial support of the Italian Ministry for
the Environment, Land and Sea (IMELS). A is the rotor projected area;
U is the wind speed;
Cp is the rotor power (PT) to wind power ratio.

Table 1 It is noteworthy that Pel is proportional to the wind speed cubed
Incentive scheme for wind power plants in Italy [6]. [22]. This implies that for a slight wind speed increase a greater
power value is achievable.
Power (kW) Lifetime of the plants (yr) Incentive fee (€/MW h)
Hence, in order to increase the inlet wind speed close to the
1 < P 6 20 20 291 rotor blades, an artificial speed up can be applied. Consequently,
20 < P 6 200 20 268 a convergent duct was integrated in a commercial micro wind tur-
200 < P 6 1000 20 149 bine (see Fig. 2).
1000 < P 6 5000 20 135
P > 5000 20 127 As it is well known, the Venturi effect leads to a fluid speed
enhancement corresponding to the narrower section (where