1) having a significant contribution from RES to satisfy energy demand—even though in 2008, for the first time, domestic electricity demand was less (–0.7%) than in 2007—and 2) improving environmental indicators, by reducing air and water pollution through the replacement of older conventional generating plants.
In 2008, the electric energy generation from RES was quite good and much better than in previous years. This was mainly due to a strong increase of electricity production from hydropower and, to a much smaller extent, wind, taking into account the different relative weights of these two clean sources.
In fact, the production from wind grew by 63% compared to 2007, according to 2008 provisional electricity statistics provided by Terna (Italian Transmission System Operator), while that from hydro increased by only 18%. However, in absolute terms production from hydro was 45,511 GWh (albeit including output of some pumped-storage plants).
Production from wind was 6,637 GWh, with growth of approximately 2,500 GWh. Hydro, with about the same installed capacity in 2008 as 2007, had a substantial production growth as a consequence of more rainfall and snow in the last months of the year. Wind energy also enjoyed a particularly windy year, but its substantial growth in energy contribution was mainly the result of a massive increase in power capacity. More than 1,000 MW was put into operation in 2008, establishing a new annual record. Wind power capacity rose in 2008 by a surprising 37% (3.736 MW in total), because many wind farms, totaling about 370 MW, were connected to the grid in December.
As to the whole electricity system, according to Terna’s provisional data, the 2008 electrical demand on the domestic grid (including both customer loads and grid losses) was about 337 TWh. This is 0.7% less than 2007 and about the same as demand in 2006. The balance between imported and exported electricity improved to almost 40 TWh, 14.5% less than 2007. Italy’s 2008 gross domestic electricity consumption (i.e., 318 TWh of gross domestic production plus the balance between import and export) can therefore be considered to be about 358 TWh.
Altogether, hydropower (less an estimated 5.5 TWh from pumped-storage plants, which cannot be considered as a RES output), wind energy, and geothermal energy (the last one with the same production as 2007), totaled some 52.1 TWh. According to GSE (Gestore dei Servizi Elettrici, the body in charge of running all RES support schemes), biomass contributed an estimated 7.2 TWh. Therefore, the total electricity contribution from RES in 2008 is estimated at nearly 60 TWh—10 TWh more than 2007 and an increase of 20%.
Wind-generated energy, as a percentage of national electricity demand, amounted to 1.9% in 2008, 63% more than in 2007. In spite of that, stronger involvement by central and local administrations and by the national transmission system operator Terna is still required for achieving, if not exceeding, the maximum wind potential of 12,000 MW. This is the estimate for 2020 according to the 2007 Renewable Energy Position Paper of the Italian government. Such wind development would contribute to reaching Italy’s 17% quota of primary energy from RES by 2020, in accordance with the so called European Directive 20/20/20. (This directive, before becoming operational, must be implemented at the national level.)
Progress Toward National Objectives
So far, the formal objective for wind energy is still 2,500 MW, which must be achieved in the 2008–2012 period, according to the national White Paper of 1999. This goal has by now been greatly exceeded. However, taking into account the aforementioned position paper issued by the Italian government in September 2007 (in response to the new 2020 RES targets set by the Plan of Action “An Energy Policy for Europe” of the European Council), the actual wind capacity objective for 2020 is now 12,000 MW, of which 2,000 MW is from offshore installations, corresponding to an annual production of 22.6 TWh.
Through new wind power capacity introduced into the electric system in 2008 equal to 1,010 MW, cumulative wind power in Italy was 3,736 MW at the end of December 2008. This is well above the former official target and is in line with national commitments on a growing role for RES in accordance with the forthcoming European Directive. The total number of online turbines was 3,588, with an increase of 645 units in 2008.
Commercial Deployment
Wind energy, through excellent results achieved in 2008 both in terms of new power capacity and, according to provisional data, electricity generation, is confirming its important role in Italy’s electricity system. It is now positioned as the third renewable source following hydro and biomass. The average capacity factor of wind plants in 2008, according to figures computed by Garrad Hassan Italia S.r.l. from
data acquired by Terna and ENEA, was as high as 0.24, appreciably higher than in 2007.
Good wind conditions in 2008 and the increased power capacity online led to a share of wind generation of 1.9% as a percentage of domestic electricity demand. Italy is experiencing a growing but still low contribution from wind energy (in 2007 the share was 1.23%), but much more must be done to reach a possible but very ambitious share of 6% to 7% of electric demand.
With 1,010 MW of new wind power capacity installed in 2008, the previous estimate of a maximum 3,500 MW of total capacity by 2008 has actually been demonstrated to be low. Now the nearest target, which should be reached very shortly, is the threshold of 4,000 MW. By the end of 2009, taking into account works in progress, the cumulative installed capacity should be some 4,600 MW.
Despite the usual difficulties faced by developers—administrative bureaucracy, opposition from a minority of environmental associations, and lengthy procedures for connection to the grid (which are becoming a real bottleneck)—wind energy deployment has been growing at a very brisk pace. Continued annual growth is anticipated of from 800 MW to 1,000 MW in the period 2009–2012. Moreover, this growth rate could be confirmed as an were also to be made by offshore installations.
The Apulia (260 MW) and Sicily (211 MW) regions were the most active in 2008, followed by Campania, Sardinia, Calabria, and Molise. Worthy of mention is the region Sardinia, where some 100 MW were installed last year despite the fact that wind energy had not been favored by the regional government. In 2007, International Power plc, a leading independent electricity generating company with interests in more than 30,000 MW (gross) of power generating capacity located in 20 countries, entered the Italian wind market. It acquired some 550 MW and gained the position as the leading player in Italy in wind generation.
International Power plc owns 1,199 MW of wind energy plants around the world, and its share in Italy of total wind power installed was almost 15% at the end of 2008. Five other energy producers in the Italian wind market—two utilities (Enel and Edison) and the wind developers IVPC, Fri-EL, and E.ON Italia—have capacity shares ranging between 7.5% and 11.2%. They are followed by several minor investors with a share up to 3%.
The IVPC Group, Italian Vento Power Corporation, is one of the leading national operators in the production and sale of electricity from wind. Since 1993, when it was set up, the IVPC Group has expanded its range of services by offering them to third-party operators. IVPC has developed and installed approximately 1,000 MW of wind capacity, which it manages, distributed over seven Italian regions. Of this capacity, it directly owns 324 MW. The IVPC Group currently has 166 MW under construction. Furthermore, through IVPC Gestione S.r.l. and its other service companies, it manages and maintains wind farms not only for itself but also for third parties.
With regard to the sourcing of financial resources, the IVPC Group is a lead player in obtaining bank loans (so-called project financing). From 2006 through 2008 alone, the IVPC Group negotiated and executed project financing bank loan agreements of approximately 696 million €. As regards intermediation in the sale of electricity and green certificates, the IVPC Group looks after the sale of electricity produced from the group’s wind farms and wind farms belonging to third parties. It carries out the same activity for the sale of green certificates belonging to group companies.
Intermediation activities for the sale of electricity and green certificates are carried out by its own organization based in Rome, which operates in the sector of electricity trading. Its aims are to maximize the objectives of the companies that own production plants, see to the care and fulfillment of all associated operations and activities (managing contracts, analyzing and checking data, monitoring stock markets, examining integrated commercial proposals, and so on), and act as interface in relations among institutions in the electricity sector.
Among wind manufacturers, Vestas still leads the Italian market with a share of total capacity close to 50% and more than 340 MW installed in 2008—one-third of the total capacity put into operation for the year. Gamesa maintains the second position, with a share of 20% and new installations totaling 164 MW. Enercon had quite a good result in 2008 with 125 MW installed, bringing its cumulative capacity to 473 MW or a 12.67% share of installed wind power.
Besides these three major manufacturers, others have entered the Italian market with shares ranging from 3.2% to 5.3%. REpower had the best result in 2008; 146 MW located in the Apulia and Sicily regions brought its total capacity to nearly 200 MW. It was followed by Nordex, which installed 109 MW, and Ecotecnia with 104 MW. GE Wind put into operation only 13.5 MW, but it should significantly increase its capacity in 2009.
The average unit power of wind turbines installed in 2008 was 1,566 kW, slightly less than the previous year, but the average unit power of all online turbines at the cumulative level still increased from 926 to 1,041 kW. The increase is mainly thanks to a large contribution provided by 2-MW turbines and a number of other machines ranging from 1.35 MW to 3 MW.
So far, no electricity producers with a single wind turbine have entered Italy’s market. However, the new incentive scheme of the 2008 Financial Law for wind plants up to 200 kW became fully operational in the beginning of 2009. Also some new rules at the regional level, make it likely that small private investors, mainly farmers and landowners, will start to install single machines with capacity up to 1 MW.
Benefits to the National Economy
Because of the increasing annual growth of wind power capacity, the economic turnover of the wind sector in the past two years rose to more than 1 billion €, including turbines and components delivered to foreign countries. The most positive effect of this progress is the growing number of employees involved in the sector. At the end of 2008, according to ANEV (National Wind Energy Association), this amounted to 18,309 positions, of which 5,353 are directly employed. The total personnel involved is subdivided as follows: feasibility studies, 2,240; manufacturing of turbines and related industry, 3,033; development and civil works, 5,246; installation, 1,421; and management O&M, 6,369.
Regarding future prospects, a study jointly carried out by ANEV and UIL (a national trade union) estimated that by 2020, assuming full exploitation of an Italian wind potential of 16,200 MW and energy production of 27.2 TWh, some 66,000 people would be employed (including indirect employment). In addition, other economic and employment benefits are related to replacement of the main components of old medium-sized wind turbines, carried out by IVPC. Another positive aspect ensuing from the rising wind power capacity and its being scattered in rural areas is increased investment in upgrading electrical grid infrastructures, mainly planned and implemented by the TSO Terna.
With awareness of the environmental and economic benefits from wind energy and the full knowledge of new opportunities offered by the changing incentive mechanism, local municipalities, entrepreneurs, investors (including foreign investors), and common citizens have shown steadily growing interest in being involved in new wind projects. Through the Ministerial Decree on 18 December 2008, the RES provisions in the 2008 Financial Law finally went into effect at the beginning of 2009.
Among other measures, this law has introduced a favorable fixed feed-in tariff for electricity generated by RES plants up to 1 MW in capacity (for wind, this limit is only 200 kW) as an alternative to tradable green certificates (TGCs). This new incentive has prompted several entrepreneurs to build, commercialize, and invest in smaller wind turbines. This market, so far a niche market, now has the opportunity to grow significantly owing to the great interest shown by people living in medium-high windy areas.
Owners of wind farms are mostly private medium-large companies, utilities, and sometimes small local firms that have joined forces with larger ones. Neither single farmers nor citizens, including cooperatives, are yet owners of medium or large wind turbines. Only small turbines are currently owned (and to a lesser extent managed) by landowners. In the near future, this tendency should change, with a growing number of single wind turbines up to 1 MW in capacity being located and run on private properties.
Industrial development and operational experience
Vestas once again in 2008 was the leader both in annual and cumulative wind power capacity installed. The company is increasing its presence in Italy by setting up three subsidiary companies. Specifically: • Vestas Italia S.r.l. is responsible for the sale, installation, commissioning, and maintenance of wind farms installed in Italy; Switzerland; eastern Mediterranean countries such as Turkey, Cyprus, Egypt, Tunisia, Libya, and Lebanon; South Balkan countries such as Bosnia, Macedonia, and Albania; and all the Middle East countries.
• Vestas Nacelle Italia S.r.l. specializes in the assembly of V52 850-kW and V90 3-MW turbines. So far, more than 2,600 nacelles have been sent worldwide.
• Vestas Blades S.r.l. is involved with the construction of blades for V52 units.
Vestas now has two commercial offices, in Taranto and Rome. Moreover, in 2008, the company inaugurated the new production line of the V90 3-MW turbine and increased the employees in its two factories in Taranto to almost 700 people.
In 2008, Leitwind was set up as a company belonging to the Leitner group. In December 2008, the company installed its first wind farm in Italy with four LTW 77 1.5-MW turbines (Figure 7). So far, Leitwind’s commercial products are two turbines, LTW 70 and LTW 77, of 1.7 MW and 1.5 MW rated capacity, respectively, and with different rotor diameters, 70 m to 77 m, as a function of the wind class of the site. Previously, Leitwind installed a few wind turbines in Italy, Austria, Bulgaria, and India. A new prototype, the LTW 80, rated at 1.5 MW, is under development and is likely to be installed in 2009.
The very first wind farm in the Italian Alps was installed by Nordex at the end of December 2008. Four 2.5-MW NM 90 turbines and one NM 80 turbine are located about 1,000 m above sea level close to the French border.
The Moncada Energy Group should soon begin producing the WPR 850/58 850-kW direct-drive turbine. In the near future, 2-MW, 20-kW, and 1.5-kW models are to be designed and built in its factory in Sicily. Moncada has received approval to build a 500-MW 400-kV merchant electrical line across the Adriatic Sea from Albania to Italy. The line is being developed as part of a wider plan for an integrated energy hub in southern Europe. This will enable Moncada to export power from its planned and already authorized 500-MW wind farm in Albania. The interconnecting direct-current (DC) cable between the Italian transmission grid and the Albanian grid will be 154 km long. Of these, 14 km will run on Italian ground (Brindisi), 10 km will be on Albanian ground, and the remaining 130 km will be laid on the seabed in the Channel of Otranto down to a maximum depth of 825 m. The two ends of the cable will be connected to conversion stations (transforming AC to DC current and vice versa) which, in turn, will be connected to a 380-kV line at Brindisi Sud (Italy) and to a 220-kV line at Babica (Albania). This project has already been judged favorably by Terna and the Albanian TSO and was also approved (9 January 2008) by the Albanian government.
The company has also developed a project for an interconnecting DC cable between the Italian transmission grid and the Tunisian one, with a capacity of 600 MW and a voltage of 400 kV. Regarding grid connection, mention should be made of Deliberation ARG/elt 99/08 issued by AEEG (the Regulatory Authority for Electricity and Gas) on 23 July 2008 to streamline further, and gather in a single document, the technical and economic conditions for connecting generating plants to electrical systems at all voltage levels. This deliberation, in effect from 1 January 2009, includes special provisions for RES plants, which should help clarify and speed up the procedures for connecting wind plants to the grid and better define the sharing of relevant costs between wind investors and the grid operator. On the other hand, a further AEEG Deliberation (ARG/elt 98/8 of July 2008) has allowed grid operators (for examle, Terna) to require that new wind plants provide some ancillary services for the benefit of the electrical system. Such services include power output modulation, cut-in power ramp control, fault ride-through capability, and regulation of active and reactive power.
Terna, with the aim of allowing the connection of growing energy production from wind into the national transmission grid, has developed the “collecting plants method” (metodo dei collettori di potenza). This method allows connection of considerable amounts of power in the safest way with environmental and economic benefits. Its main objective is to favor the connection of more than 200 MW of generation capacity to each collecting plant of the 380-kV system. Terna plans to invest 550 million € in the national transmission grid to support the development of RES, and in particular wind energy, through the repowering of existing lines, construction of new lines, and construction of connecting plants, which represent the most significant part of planned investments. Terna’s plans for new connections include the 500-kV DC 1,000-MW submarine cable between Sardinia and the mainland (to be completed by the second quarter of 2010) and an enhanced connection to Sicily. They will guarantee an increase of some 3,700 MW of transmissible energy from wind.
In September 2008, a small 80-kW wind turbine was installed by the company Blue H on a floating foundation about 20 km off the Apulian coast. This offshore turbine was installed on a 111-m depth of the seabed, where a counterweight was placed previously, and used a submerged deepwater platform. The temporary permit for the installation in the sea expired at the end of 2008, and the unit was subsequently decommissioned and brought safely back to shore. Blue H feels that it learned a tremendous amount from this experience and is confident that the know-how gained, along with its intellectual property already filed in the form of utility model and patents, will ensure its continued leadership in the field of floating wind turbines.
Blue H is currently building the first operational 2.5-MW unit in Brindisi, which it expects to deploy at the same site in the southern Adriatic Sea in 2009. This is the first turbine in the planned 90-MW Tricase offshore wind farm located more than 20 km from the beautiful coastline of Apulia.
Early in 2009, project GEOMA, a consortium led by Blue H, was selected as one of 30 recipients of Italian public funding under “Industria 2015,” a program announced by the Minister of Economic Development. The Blue H consortium is one of two wind energy projects selected by a panel of experts in Industria 2015. This Italy-based project will develop a hybrid concrete/steel 3.5-MW floating wind turbine ideal for the deep waters of the Mediterranean Sea. Consortium members are Ansaldo Sistemi Industriali, Blue H R&D, Blue H Sky Saver S.r.l, CESI RICERCA, EADS Astrium, Progeco, Società Gomma Antivibrante, TRE Tozzi Renewable Energy, and the University Federico II of Naples. The consortium aims to create an integrated solution for a floating wind turbine able to bring down the overall cost of electricity generation to be in line with the economics of onshore wind energy generation, but without the problem of negative visual impact.
Other initiatives aimed at setting up offshore wind farms on fixed foundations in shallow waters are running along the coasts of southern Italy and Sicily. For the time being, the investors are dealing with difficult permitting procedures, increasing costs, and some adverse judgments expressed by local authorities.
According to ANEV, the cost of installed wind turbines is at substantially the same level as it was in 2007. The average installed plant cost of a medium-sized wind farm (30 MW) at a site of medium complexity, with 15 km of paths/roads and 12 km of electric line for connection to the high-voltage grid, is approximately 1,800 €/kW. This cost is generally subdivided as follows:
• Turbines, installation, and commissioning, 1,270 €/kW: 70.6%
• Development, namely site qualification, design, administrative procedures, etc., 236 €/kW: 13.1%
• Interest on loans, 196 €/kW: 10.9%
• Connection to the grid, 73.8 €/kW: 4.1%
• Civil engineering work, 23.4 €/kW: 1.3%
• Annual cost of operation and maintenance has been estimated to be about 54 €/kW, which includes leasing of terrain, insurance, and guarantee
• Decommissioning cost has been estimated at approximately 5 €/kW.
The income of wind plant owners is currently derived from two sources:
• Income accrues from the electricity price obtained by selling the energy produced. Energy may be sold on the free wholesale market or directly to GSE through a special contract by which the whole production is purchased at prices set in accordance with those of the free market. Most wind plant owners choose the latter option. In 2008, the purchase price was extremely variable depending on many factors; on average it could be put at approximately 90 €/MWh.
• Plant owners derive income from the price obtained from the sale of the TGCs assigned by GSE to electrical energy produced from RES. This price, too, was very variable in 2008; average value was estimated at about 75 €/MWh.
It is also worth recalling, for the sake of completeness, that a decreasing number of wind plants have still been entitled to sell energy to GSE at the premium feed-in tariffs granted by the old scheme (CIP Provision No. 6 of 29 April 1992). In 2008, the maximum CIP 6/92 tariff for wind plants was 151.8 €/MWh (preliminary price).
National Incentive Programs
As the old CIP 6/92 system based on feedin tariffs gradually expires (incentives were granted for the first eight years of plant operation), more and more wind plants are benefiting from the current RES support schemes. The main scheme (and the only one currently available to wind plants above 200 kW) is based on a RES quota obligation and the issuing of TGCs. Producers or importers of electricity generated from nonrenewable sources must feed into the Italian grid a mandatory quota of RES electricity calculated as a percentage of the electricity produced from conventional sources in the previous year. At the beginning this percentage was 2%; in 2008, it rose to 3.8%.
Operators subject to the RES requirement have to prove compliance by returning to GSE, after the end of the year, a corresponding number of TGCs. These can either come from one’s own RES plants or be bought from other RES electricity producers. GSE grants TGCs to certified RES plants that began operating after 1 April 1999 (the so-called IAFR plants) for the first 12 years of operation (this term has now become 15 years for plants that began operations on or after 1 January 2008).
TGCs are valid for three years. TGCs can also be bought from GSE at a price that is fixed every year in accordance with a given procedure. Unlike in previous years when GSE’s TGCs were needed to meet demand, from 2006 onward the whole TGC demand has been covered by IAFR producers, mainly with hydro, wind, and geothermal plants. The ensuing competition pulled the TGC trading price well below that of GSE’s TGCs, reportedly around 70–80 €/MWh in 2008 trading. These poor price conditions have been blamed on factors including that the RES obligation percentage rose at too slow a rate, which did not allow TGC demand to grow enough.
The rules of the RES quota/TGC scheme have recently been reshaped somewhat by the so-called 2008 Financial Law (Law 244 of 24 December 2007). It took quite some time for the RES provisions of this law to become effective as they required a further Ministerial Decree, which was issued only on 18 December 2008. However, the main changes brought in by these new provisions can be summarized as follows:
• The yearly increase of the mandatory quota of RES electricity has been raised from 0.35 to 0.75 percentage points in the period 2007–2012.
• The size of all TGCs has been reduced to 1 MWh.
• RES plants that have come online after 1 January 2008 will get TGCs for a period of 15 years (instead of 12 as older plants), in a number equal to the number of produced megawatt-hours multiplied by a coefficient. The coefficient is specific for each technology (e.g., 1 for onshore wind, 1.1 for offshore wind).
• From 2008 on, the price of TGCs bought from GSE will be calculated as the difference between 180 €/MWh and the annual average market price of electricity. (For example, the calculated price for 2008 was 112.88 €/MWh.)
• The reference values and coefficients may be updated every three years.
• Until Italy has reached its RES electricity target according to Directive 2001/77/EC, GSE must buy all unsold TGCs before their expiration date (three years from issue) at a price equal to the average TGC price of the previous year.
Another important feature is that these laws also set up or restructured other incentives available to RES plants of up to 1 MW capacity. Specifically, RES plant owners can choose a fixed comprehensive incentive price for the energy fed into the grid as an alternative to electricity market price plus TGCs. This option has been allowed for RES plants up to 1 MW, but it excludes solar plants (photovoltaics actually has its own special legislation and feed-in tariffs) and wind plants above 200 kW. The comprehensive price is available for 15 years to plants that have come into operation after 31 December 2007. For wind plants up to 200 kW capacity, it is currently 300 €/MWh.
Additional new provisions give RES plant owners the option to choose, as a trading mechanism, the on-the-spot exchange of their production with the energy they draw from the grid as customers. This possibility has now been extended to all RES plants up to 200 kW, provided they came into operation after 31 December 2007. (Formerly, this limit was 20 kW.) Both of these provisions, could well open new prospects for the deployment of small sized wind turbines or plants with a single turbine up to an overall capacity of 200 kW.
R, D&D Activities
Since the introduction of a feed-in tariff for wind turbines up to 200 kW, several manufacturers of wind turbines up to 20 kW have begun scaling up projects. To date, however, only one of them, Terom Wind Energy, has developed a 55-kW turbine for low-wind site applications. Blu Mini Power, through a venture with the French company Vergnet, is entering the Italian market with a 200-kW Vergnet turbine in addition to its own smaller turbines.
In addition to universities that have been working on wind energy for a long time (e.g., Genoa, Bologna, Trento, and the Polytechnic of Milan), other universities are now conducting R&D activities: offshore wind power (Catania), towers (Florence and Padua), and small turbines (Naples). Among R&D activities of note are those carried out by the Aerospace Engineering Department of the Polytechnic of Milan. They are mainly focused on:
• Advanced control laws for wind turbines, namely development of control laws for variable-speed wind turbines for reducing fatigue damage and for gust load alleviation. Particular emphasis is placed on laws that include individual blade pitch control, account for aeroelastic effects (tower and blade flexibility), and can react to changes in the operating conditions (change in wind shear, presence of vertical and lateral wind components, operation in the wake of another turbine, and so on).
• Research activity has also led to the development of several supporting technologies, including monitoring of the wind turbine structural flexible states from strain gauges and accelerometers, and measurement of the spatial distribution of the wind over the rotor disk. The control laws are being tested both in the field on a megawatt-class wind turbine and in a high-fidelity simulation environment based on the multi-body finiteelement aero-servo-elastic code named Cp-Lambda (Code for Performance, Loads, Aeroelasticity by Multi-Body Dynamics Analysis).
• In (WT)2 (Wind Turbine in a Wind Tunnel project), aeroelastic wind tunnel models of a multi-megawatt wind turbine are designed for testing in the large wind tunnel facility of the Polytechnic of Milan. Scope of the models is the development, verification, and comparison of control laws for wind turbines, as well as the testing of extreme operating conditions.
• Software for wind turbine design and optimization is being developed. This project aims at developing automated procedures for supporting all phases of the design process, including aero-servo-elastic analysis using the multibody finite-element code Cp-Lambda, transfer of loads from aeroelastic simulations to detailed FEM models of subcomponents for fatigue and ultimate analysis, and multi-objective optimization of the machine.
The optimization procedures use the simulation capabilities provided by the Cp-Lambda code for performing: (a) aerodynamic optimization of the rotor (e.g., twist and chord distribution for maximum annual energy production (AEP), with noise constraints and maximum chord constraints); (b) structural optimization of the blades (e.g., minimum weight configuration for given design load cases [IEC-61400 DLCs], placement of frequencies, stress/strain allowables, and so on); and (c) combined aerodynamicstructural optimization (e.g., for maximum AEP over weight).
The University of Genoa is conducting several activities on wind assessment, including the development of new models. One of them has recently been developed to study the intermittent character of wind energy and its consequences for electrical power systems. Since wind energy is stochastic, a possible way to mitigate undesired fluctuations of energy output in the electrical system could be to identify the optimal allocation of wind power plants over an extended territory. This would allow lower temporal variability of the aggregate wind power output and, therefore, also guarantee a significant contribution to base load power supply. To date, this model has been applied to the case of optimal allocation of wind plants over the island of Corsica. The model is based on the identification of anemological regions and wind regimes over the territory and on the calculation of the optimal spatial distribution of wind power plants under given requirements of minimal variability of overall wind energy input (i.e., the aggregate contribution of all anemological regions to the power supply system). By means of this optimization, wind energy fluctuation in the power supply system of Corsica has been reduced by about 58%, with an energy production loss of 23%.
CESI RICERCA has been working on wind power within the framework of its research program carried out under contract to the Italian government in the interest of Italy’s electricity system. After completing its new Wind Atlas of Italy, CESI RICERCA is concentrating on better assessing Italy’s offshore wind potential, taking into account all factors on which exploitation of this potential could depend (windiness, technology, costs, etc.). Since the most plentiful resources are found in waters too deep for the current offshore wind technology, CESI RICERCA has taken an interest in the feasibility of building plants on floating foundations. Consultants assist on more specific marine issues. The effort begins with a preliminary review of different concepts of floating platforms and their moorings. Next, a computational model analyzed, under normal and extreme wind and wave conditions, the dynamic behavior and stresses of a system comprising a large wind turbine mounted on floating structures of various types.
CESI RICERCA is also looking into the practical aspects of construction, installation, and operation of floating wind turbines, taking into account technical behavior and costs over the whole operating lifetime. A specific structure configuration has been selected and examined, and loads and stresses have been calculated both in normal operation and in other critical phases, including transportation and installation on site. At the same time, the costs of this structure have been estimated to get an idea of the overall investment and maintenance costs of a wind farm with floating wind turbines versus its expected energy performance.
CESI RICERCA has also undertaken to supplement the Wind Atlas of Italy with a full Atlas of Environmental Compatibility. This work provides, as far as possible, information about protected or restricted areas and other environmental constraints that could hamper the setting up of wind farms. CESI RICERCA has also developed a software application to simulate wind farms for preliminary assessment of their visual impact on a given area. Wind-measuring masts have been set up, both offshore (on a very small island in the Adriatic Sea) and in Tuscany, to fine tune the Wind Atlas in some areas of Italy.
The Next Term
In 2009 the growth of wind capacity is expected to be similar to that seen in 2008. Accompanying increasing industrial activity is expected and consequently the creation of new job opportunities. This forecast is confirmed by the civil engineering work in progress in several regions for setting up many more hundreds of megawatts and by the Ministerial Decree of 18 December 2008 on incentives for electricity production from RES (implementing the 2008 Financial Law). Among other measures, the decree establishes a feed-in tariff for small wind turbines and helps to support the commercial value of TGCs.
Further development of R&D work can also be expected. Within the framework of Industry 2015, a new industrial policy law issued by the Italian government in 2006 and later implemented by the 2007 Financial Law, a call was published in 2008 by the Ministry of Economic Development to grant funds to R&D programs aimed at industrial innovation for energy efficiency. The announcement raised very strong interest, and many applications were submitted. Three wind power projects were approved: offshore floating wind plants, development of a large wind turbine prototype, and a system having a very small vertical-axis wind turbine and a PV device. The total eligible cost of these projects is some 50 million €, of which about 20 million € should be granted by the Ministry of Economic Development.
Authors: Luciano Pirazzi, ENEA; Claudio Casale, CESI RICERCA, Italy.
