RENEWABLE

SOURCES IN ITALY

POTENTIAL AND

APPLICATION ISSUES

Francesco Tavano

1

Table of Contents Abstract ............................................................................................................................................................. 2

Introduction ....................................................................................................................................................... 2

Italian energy balance ....................................................................................................................................... 3

Density of renewable energy on the territory (specific potential) .................................................................... 4

Land availability for plants ................................................................................................................................. 6

Affordable potential, practical potential and technical limits ........................................................................... 6

Analysis of the potential of various sources ...................................................................................................... 8

Hydropower ................................................................................................................................................... 8

Geothermal .................................................................................................................................................... 8

Wind .............................................................................................................................................................. 9

PV ................................................................................................................................................................... 9

Biomasses ...................................................................................................................................................... 9

Municipal solid Waste ................................................................................................................................. 10

Biofuels ........................................................................................................................................................ 11

Development of production and feasible potential ........................................................................................ 12

Conclusions ...................................................................................................................................................... 14

REFERENCES..................................................................................................................................................... 15

APPENDIX......................................................................................................................................................... 15

1 - Wind Power ........................................................................................................................................ 15

2 - Photovoltaics ...................................................................................................................................... 15

3 - Biomass for heating ............................................................................................................................ 16

4 - Biomass for electrical purposes .......................................................................................................... 16

2

Abstract

Starting from the Italian energy balance, this report examines current contribution of renewables together

with each production technology in order to have an indication of the specific energy productivity.

Combining these data with the territorial availability, several accessible energy potentials have been

derived. In addition, given the screening of technical and economic limitations, it is estimated the value of

the real energy potential for each source.

Finally, technical issues limiting the application of each source are revealed and, after identifying their

causes, lines of research and development needed to expand their use on a large scale are offered.

Introduction

It is widely believed that renewables could be the solution to current dramatic environmental problem.

This great confidence is enhanced by the indisputable fact that solar energy potential, alone, is far

overabundant compared to present and future humanity energy demand.

What stated applies to Italy, too: an accurate analysis of Italian various renewable capacities leads to the

conclusion that, among them, PV has the greatest potential. For instance, as we will see later, the usage of

as much as 22 000 km2 of marginal areas and industrial roofing as PV sites could result in around 144 Mtoe

of primary energy.

However, it should never be forgotten that solar energy is available only intermittently and not necessarily

when people need it: fact that greatly devalues its intrinsic value by forcing an onerous system of

accumulation.

3

Italian energy balance

Italian primary energy consumption amounted in 2012 (latest certified available data from the Ministry of

Economic Development) to 177,8 Mtoe.

Details regarding mix of sources and final consumption are shown in the table below:

TAB 1-Italian Primary energy balance (in Mtoe)

Further details concerning evolution of domestic consumption over time are given in TAB 2:

TAB 2-Annual evolution and comparison of consumption (in Mtoe)

Merely focusing our attention on energy production from renewable sources (around 27 Mtoe, 92 Twh),

which amounts to about 26-27 % of the overall Italian production, could be useful to have a look at the

following graph.

# Solid fuels Gas Oil Renewables Imported electricity TOTAL

1. Production 0,6 7,0 5,4 24,8 0,0 37,9

2. Import 15,9 55,5 86,3 2,1 10,0 169,8

3. Export 0,2 0,1 29,2 0,1 0,5 30,1

4. Stocks variation -0,2 1,0 -1,1 0,0 0,0 -0,2

5. Gross domestic consumption (1+2-3-4) 16,6 61,4 63,6 26,8 9,5 177,8

6. Consumption and losses in the energy sector -0,3 -1,6 -5,0 0,0 -41,6 -48,6

7. Transformation in electricity -11,8 -20,6 -3,3 -21,7 57,4 0,0

8. Overall final uses (5+6+7) 4,4 39,2 55,3 5,1 25,2 129,2

Industry 4,4 12,3 4,3 0,3 9,8 31,0

Transport 0,0 0,8 36,2 1,3 0,9 39,1

Civil 0,0 25,5 3,7 3,4 14,0 46,6

Agriculture 0,1 2,2 0,2 0,5 2,9

Non-energy use 0,1 0,5 5,9 0,0 0,0 6,4

Bunkering 0,0 0,0 3,1 0,0 0,0 3,1

Source\year 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Solid fuels 11,7 12,1 12,2 12,9 13,7 14,2 15,3 17,1 17,0 17,2 17,2 16,7 13,1 14,9 16,6 16,6

Gas 47,8 51,5 56,0 58,4 58,5 58,1 64,1 66,5 71,2 69,7 70,0 69,5 63,9 68,1 63,8 61,4

Oil 94,9 95,2 92,4 92,0 91,9 92,0 90,8 88,0 85,2 85,2 82,5 79,2 73,3 72,2 69,2 63,6

Renewables 11,5 11,6 12,9 12,9 14,0 12,6 13,0 14,9 13,5 14,2 14,3 17,0 20,2 22,9 24,6 26,8

Imported Energy 8,5 9,0 9,2 9,8 10,6 11,1 11,2 10,0 10,8 9,9 10,2 8,8 9,9 9,7 10,1 9,5

TOTAL 174,4 179,4 182,7 185,9 188,8 188,1 194,4 196,5 197,8 196,2 194,2 191,3 180,3 187,8 184,2 177,8

delta %

Solid fuels 4% 0% 6% 6% 3% 8% 11% 0% 1% 0% -3% -22% 14% 11% 0%

Gas 8% 9% 4% 0% -1% 10% 4% 7% -2% 0% -1% -8% 7% -6% -4%

Oil 0% -3% 0% 0% 0% -1% -3% -3% 0% -3% -4% -8% -1% -4% -8%

Renewables 1% 11% 0% 9% -10% 3% 15% -10% 5% 1% 19% 19% 13% 8% 9%

Imported Energy 5% 3% 6% 9% 5% 1% -10% 8% -8% 3% -14% 12% -2% 4% -6%

TOTAL 3% 2% 2% 2% 0% 3% 1% 1% -1% -1% -1% -6% 4% -2% -3%

4

Figure 1-Evolution over time of Italian Energy production in GWh from Renewable Sources:

Hydro (blue), Geothermal (red), Bioenergy (brown), Wind (green), PV (orange)

Few important conclusions could already be derived:

Geothermal and Hydroelectricity production remain almost stable over years

PV, Wind and Bioenergy are growing fast. PV, above all, shows an increasing exponential trend.

Renewable sources are gradually increasing their overall share

Density of renewable energy on the territory (specific potential)

The following table shows an assessment of the energy density in terms of energy obtainable from each

square km of land occupied by the plants, for each source.

Calculations has been made assuming each source technical characteristic, given the best current

technology. The range of values refers to the energy characteristics of those sites that are considered most

suitable for exploitation.

Conditions of the computation are listed in caption.

Source Type of

produced

energy

Energy density with

respect to the ground

[E/km^2]

Oil Equivalent

Chemical Energy

[ktoe/km^2]

AVERAGE Oil Equivalent

Quantity of

Energy

[(barrels/km^2)*

1000]

Wind Electrical (21 - 48) GWh (4.6 - 10.6) 7,6 (34 - 77)

PV Electrical (99 - 107) GWh (22 - 23) 22,5 (161 - 170)

CPV (CRS or

DCS

technology)

Electrical (77 - 93) (72 - 86)

GWh

(17 - 20) (16 - 19) 18 (124 - 146) + (117

- 139)

5

Biomasses

(thermal

use)

Thermal (30 - 80) TJ (0.72 - 1.9) 1,31 (5 - 14)

Biomasses

(electrical

use)

Electrical (2,9 - 7,8) GWh (0.12 - 0.14) 0,13 (5 - 12)

TAB 3-Energy density (ENEA, "Rapporto Energia e Ambiente", 2006)

-Assumption is that Electricity production is considered all devoted to final electrical consumption

-CRS = Central Receiver System

-DCS = Distributed Collector System

-Biomasses: Conversion ratio of power plants is set to 35%, which means 1 kWh = 2500 kcal

-One oil barrel = 137 kg = 137 ktoe

Last column shows the data of immediate comprehension: the energy density obtainable in the area

occupied by the plant, expressed in thousands of barrels of oil per square km.

Approximately, it turns out that, from each square km of occupied land, we could gather around 100-200

000 barrels of oil a year for PV energy, while, for biomass, values are much lower.

Wind power falls below Solar. Nevertheless, it must be stated that his commitment to the territory does

not exclude other uses (such as livestock) which should be counted too.

Anyway, it is extremely clear that, since energy production is closely proportional to the area engaged by

the installed plants, it is necessary to have an adequate territorial extension to be exploited.

It is well known that Italy is a relatively small and densely inhabited Country. The geographic configuration

of the territory is largely quite bumpy, while the plains and hilly areas are almost all committed by

agricultural and industrial activities. Therefore, first, we have to check whether there is any scope for

renewables and how much it could be extended. To answer this question, we should refer to the

penultimate column of Tab 3, setting those data up in order to obtain the la d o upatio al i de ,

defined as the area (occupied by the plants) which is able to produce an annual amount of energy equal to

1 Mtoe of oil.

To simplify, the index can be obtained by taking the average value of each range and then calculate the

spatial extent (in square km) required, on average, to produce 1 Mtoe; as follows:

Source Land Occupational Index [km^2]

Wind 131,58

PV 44,44

CPV (CRS+DCS Technologies) 55,56

Biomasses (thermal use) 763,36

Biomasses (electrical use) 7692,31

TAB 4-Required Area to collect 1 Mtoe of energy for each source

The question is, at this point: Is there, in Italy, enough availability of suitable areas for renewable energy

plants in such a quantity ou a address the hole Cou tr e erg eeds?

6

Land availability for plants

Type Extension (km2) Share (%)

Farms

­ Agricultural Area

General cropping

Permanent woody crops1

Permanent grassland

­ Woodlands

­ Marginal land and roofing

226200

­ 158340

88037

28976

41327

­ 45240

­ 22620

75.0%

­ 52.5%

29.2%

9.6%

13.7%

­ 15.0%

­ 7.5%

Rest of the territory2

75138 25.0%

TOTAL 301338 100% TAB 5-Final use of the Italian territory

1. Arborescent crops: olive groves, orchards, hazelnut groves, vineyards, poplar, etc.

2.Total amount of areas unsuitable for agricultural purposes

As you can see, marginal areas (arid, abandoned areas or roofing of industrial buildings) amount to 22600

km2, accounting for 7.5% of the national territory ('91 census data).

Obviously, these areas are not very suitable for crops. Still, they may be profitably used, for example, with

photovoltaics.

Affordable potential, practical potential and technical limits

Affordable Potential is defined as the amount of energy that could be gathered (yearly) from each

source, given the latest available technology and without taking into account any sort of limitation.

Practical Potential refers to the same concept expressed above, including technical limitations and

obstacles due to territorial compatibility with other economic activities.

For instance, considering PV systems, from TAB 3 with some little calculation, it is derived that in order to

produce 1 TWh of electricity we need as much as 10-12 square kilometres of ground (considering the

average irradiance in Southern Italy, for instance).

Therefore, without considering any kind of limit, we could use 20000 square kilometres of marginal areas

gathering around 1670 TWh per year which, given that 1 TWh = 0.086 Mtoe, equals to 144 Mtoe of primary

energy. Thus, we could easily state that Italian Affordable PV potential matches the order of magnitude of

Cou tr ’s demand.

As shown in the next pages, repeating same kind of considerations over all other sources:

Renewables, taken together, constitute a potential reserve of energy whose amplitude is

comparable with both current and future Italian energy demand, and this fully justifies the great

interest allocated on these sources.

7

Unfortunately, this idyllic picture is disturbed by the presence of some technical constraints and

economic obstacles that, if not removed, may greatly affect the effective exploitation of this great

potential, leading to a much lower practicable value. In particular, this refers to those sources

producing electricity intermittently, such as wind and PV: precisely those from whom you expect a

decisive contribution to energy and environmental problems.

For these sources, current limit is not only economic, but also technical.

More specifically, the limitation is due to the development model adopted for plants, which are largely

designed for direct connection to the grid, without any energy storage subsystem. The intermittency of

random power production introduces a restrictive effect on the connected amount of power that the

overall grid is able to accept. Exceeding the limit can result in a huge lack of stability of the network,

ending up in nationwide blackouts.

Over the existence of this obstacle all experts agree, while on its quantitative consistency, instead, they

normally do not. The reason for this need to be found in the great difficulty to outline a model for

computing the great structural complexity of the grid, which hosts itself a wide variety of generators

from different technical characteristics (hydroelectric, thermoelectric oil, gas, combined cycle turbines,

etc.). So far, there is no reliable calculation published on this theme.

Anyway, the most recent experimental demonstration of the presence of this limit (and its magnitude)

has occurred on the night of September 28, 2003 at 3:25 in the morning: a massive blackout of the

network throughout Northern Italy.

It may be instructive to have a quick look on what happened.

The initial cause was the fall of a tree on the high-voltage line that comes from Switzerland with

consequent abrupt withdrawal of electrical supply. Following this event, the sudden increase of

demand on the line that connects Italy to France has dealt a blow to the control system of the French

line, who had to interrupt its supply. This led the automatic control system of our network to provide

with a series of releases for the protection of the generators in operation in Italy starting from

Piedmont. Thus, all Northern Italy has been lacking in electricity.

The technical analysis of the national grid during this event allows us to learn an important lesson.

At 3:20 (September 28th

, 2003) the power in the network amounted to about 21000 MW: 3000 MW

came from France, 2000 MW from Switzerland, while the power generated in Italy amounted to

approximately 16000 MW.

According to an ENEL study, the reaction capacity would allow to handle power variations up to 1600-

2400 MW.

The sudden, quick lack of all of those 5000 MW resulted in a sharp negative variation of around 31 %

out of the overall power by generators active in the network. Thus, abundantly overcoming safe limits,

resulting in power failure.

Wind power plants and grid-connected PV put into the grid random and variable power. When

fluctuations reach a value comparable with the safety limit, the capacity of reaction of others

generators in the network becomes insufficient to compensate and the situation comes dangerously

close to the one described above. However, because of the geographical spread of the facilities of

renewable sources, we must consider the fact that such an event of a sharp, simultaneous change in all

the connections is very unlikely to happen.

8

This allows you to tackle the subject with a certain degree of freedom, compared to the limit estimated

by ENEL. In conclusion, more optimistically, we can assess that the configuration of the park of

thermoelectric generators in the Italian network allows you to connect systems with intermittent

power for a maximum of about 20 -25 % of the active power over the network. Without considering the

worst case, that may occur as has already happened, this amount of power per day in the Italian

network amounts to about 50000 MW. This corresponds, in our scenario, to the connection of up to

(approximately) 10000-12500 MW of intermittent power (Wind and PV). The annual net production

corresponding to this limit would therefore amount to about 15-18 TWh (in typical Italian sites of 1500

kWh/kW), that is 3-4 Mtoe.

The consequence of this limitation is that, compared with the high potential of these sources (please

note that solely PV can deliver more than 144 Mtoe), the intermittent generation reduces the

contribution to a practical maximum of 3-4 Mtoe which has, moreover, to be divided between wind

and photovoltaic.

This fact should be taken into account in the upcoming analysis.

Analysis of the potential of various sources

Hydropower

Sticking out the present situation, it is clear that you will have to rely on a diminishing contribution of

hydropower, as it appears today in production crisis for the reduction of the average rainfall. Consider,

for example, that the production has fallen from 54 TWh in 2001 to 38 TWh in 2007, while the total

capacity of the plant has remained roughly constant at a value of 17.4 GW. Considering still possible

marginal growth in the number of small-river plants, we will make the assumption that this increase

will offset the further decline in general, managing to maintain roughly constant the current

contribution of 40 TWh, corresponding to 8.8 Mtoe. In summary:

Affordable potential: 17,4 GW 54 TWh 11,9 Mtoe

Practical potential: , 40 8,8

Geothermal

Because in recent years the total power of the plant has remained fixed to 711 MW, production growth

was limited in a better capacity utilization (GSE, 2012). Expanding the time base to the last three years,

it emerges that the capacity is increased by 30 MW.

Affordable potential: 1 GW 7,8 TWh 1,7 Mtoe

Practical potential: , , (territorial limit)

9

Wind

The annual grow rate of electricity production has been around 26% in recent years with a leap of over

40% in 2012. Power growth trend is definitely exponential, in theory. Sadly, Italian wind potential is

limited by both the availability of sites with adequate wind airspeed and by the intermittent nature of

the power flow. Therefore, it is unthinkable that the present rate of growth can be upheld for very

long. ANEV (National Association of Wind Energy) itself estimated, optimistically, that the maximum

installed capacity could get to 16,000 MW (ANEV, 2009): potential value to be considered accessible.

Thus, as the current average capacity factor of wind national farms is around 1500 annual equivalent

hours, the maximum annual production of electricity will get to about 24 TWh or 5.3 Mtoe.

Considering the presence of plants acceptance limit in the network (12500 MW) and taking into

account that this limit is also shared by photovoltaics, we could assume that about 10,000 MW are

available for wind power and 2500 for photovoltaics, for instance.

Affordable potential: 16 GW 24 TWh 5,3 Mtoe (territorial limit)

Practical potential: 10 15 3,3 (technical limit due to intermittent generation)

PV

Thanks to incentives of the Energy Bill, the photovoltaic power installed is increasing considerably.

Even in this case, the growth is exponential, but, instead of wind, here limit on the availability of sites is

almost non-existent, considering the 20,000 km2 of arid and abandoned land and 2600 km2 of

industrial and commercial buildings coverage. Considering the fact that technology of solar thermal

insists on same sites, for PV systems we need to assume as much as 50 % of marginal areas (affordable

potential) that is 10000 km2, corresponding to 833 TWh.

In addition, photovoltaics is an intermittent source as well as wind power. Therefore, there are some

technical limits in connecting systems to the grid (which is shared with the wind). However, given that

the state of development of the installed capacity is far from this limit and standalone plants are very

common as well, nowadays, the only effective limit to the growth has to be found in the availability of

public funds to be allocated on photovoltaics.

Considering current trend of increasing cell efficiency, smart grid development, and latest available

incentives, we can claim there is a practical potential of around 100 TWh (TERNA, 2013).

Affordable potential: 560 GWp 833 TWh 71,6 Mtoe (territorial limit)

Practical potential: 67,2 8,6

Biomasses

10

As for the potential available, we can refer to the Annual Report 2003 by ITABIA (Italian Association for

Biomass), which shows the results of the study done for the Ministry of Environment with the national

inventory of resources as follows:

Dedicated Crops 4 Mtoe

Woods

Agricultural agro-industrial residues

Biogases from landfills and livestock

Total resources 23 Mtoe

Effective availability for energy use (50%) 11 "

We have therefore an accessible undifferentiated potential of 23 Mtoe and a practical for energy uses

of 11 Mtoe.

Today's figure of biomass for electrical purposes of the total energy use is about 33%. Assuming that

this share will remain unchanged, we consider a feasible potential for electricity production from

biomass of 3.6 Mtoe, while 7.4 Mtoe remain available to thermal applications. Therefore:

Affordable potential: 10000 MW 50 TWh 11,6 Mtoe

Practical potential: 16 3,6

Municipal solid Waste

The actual production of electricity from municipal solid waste amounts to about 3 TWh per year and

current annual growth rate is 3.4%.

The present share of MSW usage for electricity generation is approximately 8% out of the total

municipal waste collected. Therefore, today, 92%, corresponding to an available potential of about 37

TWh, is intended to landfill.

There is such a huge growth potential over the contribution of energy produced by MSW, to consider

its share to reach up to 50 %. This means, considering a feasible potential of about 19 TWh per year,

equivalent to about 4 Mtoe of primary energy:

Affordable potential: 7300 MW 37 TWh 8 Mtoe

Practical potential: 19 4

11

Biofuels

All estimates made over the availability of land suitable for the cultivation of oilseeds agree on an

amount equal to 0.6-0.8 hectares. Since the specific productivity is about 1 Mtoe of biofuel for 1 million

hectares, the available potential may reach up to about 0.8 Mtoe (Biofuels Italy, 2008).

Since there are no obstacles to the development needed to engage the available land, the feasible

potential comes to coincide with the accessible one.

Affordable potential: 0,8 Mtoe

Practical potential: 0,8 Mtoe

The following tab sums up all results.

Source Affordable

potential (TWhe,th)

Affordable

potential (Mtep)

Practical potential

(TWhe,th)

Practical

potential (Mtep)

Hydro 54 11,9(1) 38,5 8,5(1)

Geothermal 7,8 1,7(1) 7,8 1,7(1)

Wind

PV

24

833

5,3(1)

71,6(2)

15

100

3,3(1)

8,6(1)

Biomasses

(elettr.)

50 11(1) 16 3,6(1)

MSW (elettr.) 37 8,1(1) 19 4,2(1)

Biofuels 9,3 0,8(2) 3,6 0,8(2)

Totale 1015.1 110.4 200 30,7

TAB 6-Energy potential and feasibility 1-Conversion ratio 1TWhe = 0,22 Mtoe (oil equivalence)

2-Conversion ratio 1 TWhth = 0,086 Mtoe (physical equivalence)

12

By examining the table, the discrepancy between the size of the available potential and the potential of

feasible for photovoltaics dramatically is unveiled. Talking about PV, faced with an energy availability in the

area definitely bigger than 70 Mtoe, the acceptance deadline of plants, given the simultaneous presence of

wind farms, allows its exploitation for only about 8-9 Mtoe. This fact has a negative effect on the total

budget.

In conclusion, the analysis of the situation of the different technologies highlighted the availability in the

Country of a potential corresponding to about 110 Mtoe of primary energy; magnitude comparable to the

energy needs of the country.

The presence of the technical and economic limitations reduce this potential to a value actually feasible

only 30 Mtoe.

Development of production and feasible potential

With reference to Table 6, we notice that some sources, such as hydroelectric, geothermal and biofuels

have virtually reached saturation of their potential, while others, such as biomass and municipal solid

waste, still have a certain degree of exploitation.

The situation is different for wind and photovoltaics.

These sources have been grouped into a single box in Table 6 because of their common feature to generate

power intermittently. We observe also that the available potential energy in Italy is limited by the

availability of windy sites for the plants and that this limit coincides practically with the feasible potential,

which in turn is limited intermittency of the source. This fact prevents the connection of the installations in

the network above a certain threshold. Given the large growth rate of the industry, we have to assume that

the exploitation of the full wind potential can be completed within a few years. Therefore, from this source

we cannot wait for a further contribution compared to the table.

For PV, however, the available potential is very large, while the feasible one is marginal. We have seen that

the cause of this drastic reduction is mainly due to the lack of funds available for incentives and, secondly,

to the intermittent source. The result is that, on the one hand, we have a huge amount of solar energy and,

on the other hand, we are able to exploit only a very small part. The expectations placed on this promising

technology, especially in relation to the requirements of environmental remediation, risk to be completely

disappointed.

Despite the fact that previous conclusion has been known for a long time, the industry ignored it, preferring

to focus its attention on the market of current systems, technological improvements and cost cutting of

plants. Unfortunately, policy makers, who should have to look at the strategic aspects, have ignored the

presence of these limits so that no one thought of possible solutions to overcome it. On the other hand, the

growth of renewable sources has not yet met the technical limit described above, since the total volume of

installations that remained below the alert level. However, today the situation has changed. The current

development of sales of wind and photovoltaic systems has recently undergone a major exponential

acceleration: for example, wind energy, is rapidly approaching the limit of acceptance of the network.

It is by now clear that you need to change the development model of systems with respect to renewable

electricity if you really want to seriously take advantage of these green sources.

13

The possibility of making weekly, or even seasonal, periods of accumulation could finally allow to fully

exploiting their real potential, bringing the contribution of these sources in the order of 100 Mtoe per year.

At this point, two questions may spontaneously arise:

Is this solution technically feasible?

How much does it cost?

The answer to the first question is yes . There are nowadays reliable technologies that would allow the

accumulation of renewable energy for considerable periods of time (electrochemical storage in the new

high-capacity batteries, thermal storage in molten salts and conversion to hydrogen).

It is all up to make a promotional effort to bring at industrial stage of development the different solutions.

Figure 3- Systems with storage to overcome Intermittence of Renewables

Figure 3 shows the block diagram of the system to be adopted by plants to overcome part or all of the

effects of the source intermittency and ensure more reliability to the network.

For example, it has been estimated that the ability to store electrical energy over 24 hour period would

allow an acceptance limit increase of the network up to about 40%, compared to current active power.

About economic feasibility, what can be said is that the addition of the storage system introduces an

increase of the overall cost, estimated in a 30-40%.

Therefore, we have an increase of the production cost of kWh, but at the same time, the removal of the

discontinuity in supply, greatly increases the economic value of the energy through the programmability of

its dispatching. In other words, the increase in economic value produces a partial compensation of the cost

added by the accumulation, so it is believed that the large-scale development of such systems (and the

consequent reduction of costs) could lead quickly to competitiveness.

14

Conclusions

1) The potential of renewable energy is overabundant compared to the national demand. Therefore, if not

fully independent from current massive energy import from abroad, Italy could at least try to align itself to

average European level.

2) Intermittent random sources introduce technical and economic barriers that prevent producing

significant amount of electricity.

3) The current application model (without storage systems in direct connection to the grid) allows only a

partial replacement of fossil fuels.

4) It is necessary to intervene immediately with shares of R & D on the supply system by improving

technologies in order to overcome the technical and economic barriers.

5) It is necessary to complete production systems with low cost energy storage systems in order to ensure

temporal continuity in the supply.

6) Without these interventions, the current public incentives are likely to produce inefficient results

compared to the need of replacing fossil fuels for environmental remediation.

7) Majority of incentives should be dedicated to PV development, which still represents the most promising

technology.

15

REFERENCES

. ANEV, , Re ord per l’eoli o: ANEVAPERENEAG“E

2. Biofuels Italia, 2008, Piattaforma Tecnologica Italiana Biocarburanti per lo Sviluppo del Settore,

Position Paper

3. ENEA, Mi istero dell’I dustria, Mi istero dell’U i ersità e Ri er a, , Fo ti Ri o a ili di

Energia: Libro Verde Nazionale, Roma 15/7/1998

4. ESTIF, 2008, Solar Thermal Markets in Europe 2007, Report ESTIF Giugno 2008

5. GSE, 2013, Statistiche sulle fonti rinnovabili, www.gse.it

6. IEA, 2008, Key World Energy Statistics, Report 2008

. ITABIA, , Le io asse per l’e ergia e l’a ie te

8. Terna, 2013, Statistical Report 2013

9. The Ministry of Economic Development, BEN - Bilancio Energetico Nazionale, Roma 2013

10. UPI, 2009, Data Book

APPENDIX

1 - Wind Power

· Wind turbines of 1 MW;

· Sites with average wind speed measured at 10 m above the ground equal to (5 ¸ 6.5) m / s;

· Productivity corresponding machine (1800 ¸ 2800) MWh / MW;

· Arrangement on the ground of the machines in square lattice with a pitch equal to 7 diameters of the

rotor;

· Efficiency of wind turbines 29%;

· Energy territorial yield (20.7 ¸ 48.4) ktoe / km2 per year;

· Conversion factor for electricity (1 kWh = 2200 kcal kep = 0:22).

2 - Photovoltaics

· Solar Modules plans arranged in fixed panels facing south and tilted according to the local latitude;

· Sites insulation: global annual average of 1650 kWh / m2 (Central Italy) and 1800 kWh / m2 (South);

16

· Conversion efficiency of the modules of 19% (i.e. Modules SPR 315E Sun Power Corporation);

· Net plant level conversion efficiency equal to 15%;

· Manufacturability: annual electricity plant level equal to (247 ¸ 270) GWh / km2;

· Factor occupation of the ground to avoid mutual shading of 2.5;

· Annual savings equivalent to oil (22 ¸ 23) ktoe / km2.

·Solar thermodynamic: linear parabolic mirrors technology (DCS);

· Mirrors: cylindrical parabolic section facing south with sun tracking on the vertical axis;

· Sites with direct component annual insolation of 1500 kWh / m2 (South Italy) and 1800 kWh / m2 (Sicily);

· Conversion efficiency electric plant level equal to 16%;

· Manufacturability: annual electricity plant level equal to (216 ¸ 259) GWh / km2;

· Factor occupation of the ground to avoid mutual shading of 3.0;

· Electric territorial yield (72 ¸ 86) GWh / km2 per year;

· Annual savings equivalent to oil (16 ¸ 19) ktoe / km2.

3 - Biomass for heating

· Plantations of fast-growing woody crops (Poplar, eucalyptus, black locust, willow, etc.);

· Annual productivity in terms of dry matter equal to (18 ¸ 48) t / y;

· Conversion factor: 1 t dry matter = 16 744 GJ (1 kg = 4000 kcal);

· Productivity: annual net energy (less spending crop of 10 GJ / y) of (300 ¸ 800) t / y;

· Equivalent in oil (1 toe = 41,868 GJ) of (0.7 ¸ 1.9) ktoe / km2.

4 - Biomass for electrical purposes

· Plantations of fast-growing woody crops (eg. Poplar, eucalyptus, black locust, willow, etc.);

· Annual productivity in terms of dry matter equal to (18 ¸ 48) t / y;

· Conversion factor: 1 t dry matter = 16 744 GJ (1 kg = 4000 kcal);

· Productivity: annual net energy of (300 ¸ 800) GJ / y;

· Conversion efficiency of thermoelectric power plants: 35%;

· Productivity: annual electricity: (105 ¸ 280) GJ / y = (29.2 ¸ 77.8) MWh / y = (2.9 ¸ 7.8) GWh / km2;

· Conversion factor for saving conventional oil: 1 kWh = 2200 kcal;

· Savings oil equivalent (1 GWh = 0:22 ktoe) equal to (0.64 ¸ 1.7) ktoe / km2.