Newsgroup: it.discussioni.energie-alternative
Titolo: Massimizzare la produzione fotovoltaica in rapporto al terreno occupato

 
Articolo interessante su un aspetto poco considerato:
 
https://www.linkedin.com/pulse/east-west-photovoltaic-plants-eduard-foved-johe
 
 
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When thinking about PV plants, common sense leads us to think in multiple
rows of PV modules facing south (if in the northern hemisphere; in the
southern hemisphere facing north). Or if a more energy-optimised design is
preferred, horizontal single-axis trackers can be used, with modules
following the sun’s path from east to west.
 
However, what do these two designs have in common? A considerable inter-row
spacing. This spacing is mainly required to avoid self-shading between rows
of modules, but also for maintenance and safety reasons. In average, we
could find standard PV plants with land-uses somewhere in between 0.6 and 1
MWp per hectare (which is to say ground coverage ratios ranging from 0.3 to
0.45), being the lower packing estimates typical for 1-axis tracking
plants.
 
In a time when massive PV deployments are expected, shouldn’t be land-use a
real concern? In Europe and in other regions, land is not abundant and its
leasing costs are on the rise. Here it is where east-west PV plants could
play an important role.
 
In east-west PV plants, half of the modules are east-oriented and the other
half west-oriented, creating a roof-like structure. Normally, they present
shallow tilt angles no greater than 10 degrees. Inter-row spacing can be
largely reduced due to the minimal gaps between rows (with only some
interior service roads), inducing a high-power density which ranges from
1.2 to 1.5 MWp per hectare. East-west designs are not new at all, they are
well-known in commercial and industrial rooftops.
 
Some large-scale PV plants already use this kind of configuration: both the
largest European PV plant (Cestas, France, 300 MWp) and more recently the
world’s largest single PV plant (Noor Abu Dhabi, UAE, 1177 MWp; seen in the
cover photo), present an east-west design.
 
Despite not being optimised in module orientation (thus not optimised in
kWh/kWp), this configuration could maximise (in some cases) the energy
obtainable from a given extension of terrain (MWh/ha). Let’s show this fact
with an example based on SAM-NREL calculations:
 
* A 30 degrees fixed-tilt PV plant in Seville could produce around 1650
kWh/kWp. Taking an average power density estimate (0.8 MWp/ha), we obtain
an energy density of 1320 MWh/ha.
 
* An east-west plant in the same location could produce around 1400
kWh/kWp. Taking the lower power density estimate (1.2 MWp/ha), we obtain an
energy density of 1680 MWh/ha, roughly 30% more energy produced in the same
extension of land.
 
Moreover, east-west designs allow for the dilution of some important costs,
such as land costs, BOS costs or connection costs. In some particular cases
where these costs are really significant, a LCOE advantage could be
achieved (though it is highly dependent on the project’s location and its
cost structure). To a great extent, the economic feasibility of these
plants is a consequence of the large module price drop over the last years.
 
Last but not least, an east-west orientation involves a flatter generation
profile, which, in principle, should help grid operators coping better with
energy demand (production starts earlier and ends later in these plants).
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-- 
1) Resistere, resistere, resistere.
2) Se tutti pagano le tasse, le tasse le pagano tutti
Soviet_Mario - (aka Gatto_Vizzato)

 
https://www.linkedin.com/pulse/east-west-photovoltaic-plants-eduard-foved-johe
 
 
Piu' che poco considerato, e' recente, da quando i moduli sono scesi
sotto i $400/kW(p). Prima il terreno doveva essere proprio caro
perche' l'idea avesse senso. Tra parentesi, l'installazione
ad 1 asse, come va a finire ?
 

 ad 1 asse, come va a finire ?
 
Per quella località il PVGIS mi da una produttività di 2085 ore.
 
Prendendo per buono il dato di 0,6 MWp per ettaro fornito nell'articolo,
abbiamo quindi una produzione di 1251 MWh/ettaro. Un valore leggermente più
basso dell'installazione fissa.
 
Anche ipotizzando di utilizzare la stessa densità di un impianto fisso
(perdendo qualcosina in produzione per gli ombreggiamenti) la soluzione "a
tetto" continua ad essere la migliore; sempre che il dato di 1,2 MWp/ettaro
sia corretto, ma così a spanne direi di sì, anzi, un po' sottostimato.