SOLAR PHOTOVOLTAICS GRID PARITY
WE ARE LOOKING FOR LAND PLOTS OF 10 HECTARES MINIMUM
TO BUILD GRID PARITY SYSTEMS, KEYS IN HAND
WE ARE LOOKING FOR LAND PLOTS
10 HECTARES MINIMUM, TO BUILD PHOTOVOLTAIC INSTALLATIONS, GRID PARITY
Those who are interested, carefully read the following points and
Download the HANDBOOK and the following documents in the DOWNLOAD section
SOLE SPOKESPERSON : IBS looks for the right areas where to place the installations and provides for all the bureaucratic procedures from the grant application from Enel / Terna to the grant issuance .
INVESTORS : the investors are already ready to buy the licenses / grants Grid Parity as soon as they will be issued .
GUIDELINES : it is important that the plots respect the following terms . For this reason, we recommend you to read them carefully . Thank you for your collaboration . We hope you will have a productive long-term collaboration with us .
THIS COMMUNICATIONS IS FOR :
- Landlords in Italy
- People in charge of plot announcements
- Rental agencies
- Technicians and operators in the renewable energy sector, especially in the PV sector
- Professional organizations : Agronomists, Surveyors, Engineers, Architects, Experts ( Land Surveyor, Engineer, etc)
Professional studies relevant to the sector
SIZE OF THE GRID PARITY INSTALLATIONS THAT WILL BE BUILT : from 5-10 MW to 40 MW-50 MW or more
HECTARES OF PLOTS NEEDED FOR 1 MW IN GRID PARITY : almost 2 Hectares every Megawatt depending on whether solar trackers are used or not . Plots have to be adjacent or at least 1 – 2 Km distant from each other, so that the connection in the substation can take place without any problems
LEASEHOLD ESTATE OR PURCHASE RIGHTS : it is possible that landowners sign a contract in which the investor pays a leasehold estate for 25 years + 3 years or + 5 years or the investor can buy the plot . Land plots fit the requirements all over Italy ( North Italy, Central Italy and South Italy )
REGIONS WHERE YOU CAN BUILD GRID PARITY INSTALLATIONS : Land plots are available in all ITALIAN regions .
Investors are interested in land plots all over Italy and its regions : it is important that lease charges or plot sales and soil radiation allow to obtain a return on investment consistent with the business model .
Some investors prefer the following regions : Abruzzo, Basilicata, Campania, Lazio, Molise, Puglia, Sardinia, Sicily, Umbria . Some investors consider the region Calabria .
IT IS IMPORTANT TO VERIFY that there are no urban restrictions and limitations on building GRID PARITY PV systems on plots in each region in Italy .
REGARDING SARDINIA : it is important that plots are industrial and not agricultural .
SUMS PAID TO LANDOWNERS FOR THE LEASEHOLD ESTATE : the sum paid to landowners in Euro per Hectare per Year for the leasehold estate will be decided with the investor and the owners, depending on the Region where the plots are and on the investor type . The investor can also pay the plots ’ leasehold estate in a single discount rate solution .
SUMS PAID TO PLOT OWNERS IN CASE OF SALES : the sums paid per Hectare in South, Central and North Italy will be discussed individually and negotiated with the investors and the owners . The investor knows the variable costs per hectare depending on his own financial model .
GRID PARITY “ READY TO BUILD ”
Ous investors also consider purchasing ready to use licenses where the installation can be built immediately .
THESE ARE THE STEPS TO POINT OUT THE LAND PLOT FOR THE GRID PARITY INSTALLATIONS :
SCREENING : landowners or people in charge of plot announcements who are in touch with the owners will be asked to send :
- PLOT TYPE : flat, sloping, soil pitch
- GOOGLE EARTH and IMAGES with the accurate coordinates and the highlighted plots perimeter.
This will allow us to : verify the plots, conduct simulations, determine the radiation in that area, verify if the plots are adjacent or if the distances between them are consistent with the requirements needed for the construction of GRID PARITY installations .
After a first and quick check is made in order to give the green light to the construction, we will need to sign the prior agreements of the following documents :
- BUILDING PERMIT
- CADASTRAL CERTIFICATES
INFORMATION ON THE CLOSEST ELECTRICAL SUBSTATION OR ELECTRICAL ROOM AND RELATED CONNECTION : it is just as important to know the plots distance from the closest Enel / Terna electrical substation, if there is average or high voltage ; to know the electric line capacity, the possibility to connect in substation and the costs of a connection in the electrical plant of an already existing substation . The creation of a new substation can be done for GRID PARITY PV installations starting from 30 MW – 40 MW . At the same time, the adjacent active high voltage line will be directly intercepted . In case of any doubts, you can send pictures of the aerial electric line both average and high voltage or pictures of the electrical substation or room, asking for advice .
PRIOR AGRREMENT THAT LANDOWNERS WILL HAVE TO SIGN : if the results on the tests made on plots and on the possibility of connection in the substation are positive, we will sign a prior agreement and start the working phases and bureaucratic procedures . IBS will provide the Autorizzazione Unica ( an Authorization which constitutes the necessary and obligatory title for the construction and commissioning of PVs ) with the help of experts :
- Autorizzazione Unica ( AU ) including, geological prospecting and exams and range reconnaissance
- Design and presentation of TICA ( Testo integrato delle connessioni attive, is document that states technical – economic terms and conditions for the connection to the grid of electric power production plants and it refers to a connection request made starting from January 1st 2009 ) and different proceedings, participation to any kind of meeting with the Authorities in charge until the AU is obtained and PV installations can be built .
TIMINGS : even if each region has its different timings and procedures, completing the whole bureaucratic procedure to receive the Autorizzazione Unica usually takes about 6-10 months . Timings start after the positive result of :
- the preliminary analysis of the plot documents and after having signed the preliminary contracts with the owners
- the analysis of the documents that will be sent to the conferenza dei Servizi present in the Region ( an institution of the Italian legislation that simplifies the activity of the Italian public administration ) which collaborates with our architects .
AGREEMENTS : with the people in charge of plot announcements or partners that will facilitate plot announcements or landowners ’ announcements, we will sign the agreements that protect them for the recognition fees . We will also sign a NDA ( Non – Disclosure Agreement ) on the exchange of confidential information both with the person in charge of plot announcements and with the landowners . IBS wants to have a productive long-term synergy with those who will want to cooperate .
COOPERATE WITH US
We are looking both for people directly in charge of plot announcements, different types of operators who are in touch with landowners and also people who aim to become our Area Managers . The Area managers’ job will be that of coordinating the people in charge of plot announcements, collect proceedings and being responsible for the information . They are also a reference point between landowners or plot announcers and IBS in case of any problems .
APPLY FOR THE POSITION BY SENDING US YOUR PERSONAL DETAILS AND CV
PROJECT AND INFORMATION STAKEHOLDERS
IF YOU ARE INTERESTED IN COOPERATING WITH US
WE SUGGEST THE FOLLOWING TESTS AND DOCUMENT DOWNLOADS TO OUR ANNOUNCERS / AREA MANAGERS :
GUIDELINES : it is an Information Handbook in PDF which aims is to research the right areas and to operate independently making the information exchange more efficient .
INFORMATION VIDEO : the video ’ s aim is to facilitate the process and to reveal in advance the information that will be needed in the different phases. In this way, it gives an immediate overview .
GREENFIELD PRELIMINARY FORM OF THE AREA : this initial document has to be downloaded in order to send the first information by plot owners or announcers with the google earth picture of the plot and its coordinates and perimeter attached .
SIMULATOR OF THE COMPATIBILITY BETWEEN THE ELECTRICAL LINE COSTS AND THE BUDGET : it is an excel file that simulates the low and average voltage connection costs . We suggest you to write the required values into the yellow cells ( where some values are written as an example ) and a calculation and first estimate will be made automatically . Regarding high voltage, CONTACT US .
PROGRESS REPORT OF THE AUTORIZZAZIONE UNICA : in this section our co – workers, partners, investors and announcers are able to monitor the progress report of the Autorizzazione Unica regarding the plots, where the procedure to obtain this authorization in Grid Parity together with the plots data is taking place
FOR FURTHER INFORMATION OR CLARIFICATIONS
Contact us via E-mail with your personal information in order to reach us or to begin working with us . One of our managers will contact you within 24 hours and will give you the necessary information :
Mail : ibs(a)doingbusinessibs.it
Skype : doingbusinessibs ( location Roma )
Notes : In the E-mail given to contact us the at sign is written with this symbol (a), instead of this one @ in order to respect our company policy regarding cybersecurity On the Internet there are some browsers and automatic programs that could use the active email in the websites and create harmful SPAM communications . However, by replacing the symbol @ with (a) this problem is avoided . Thus, for everyone’s safety, we ask you to take note of the email and to write us from your email account or server . Or, you could click on the following image . This will direct you to the page where you can CONTACT US through the website special area . Thank you for your cooperation .
DISPENSATION AND MATERIALS
ON SOLAR PHOTOVOLTAIC
THE SOLAR RADIATION
The solar radiation is the electromagnetic energy that is emitted by the process of the fusion of hydrogen in the sun and it turns into helium atoms ( He ) .
Solar energy, that in a solar year crosses the atmosphere and arrives on earth, it is only 1/3 of the total energy that is intercepted by planet earth out of the atmosphere and the 70% of the energy ends in the sees .
The remaining energy ( 1,5 x 1017 kWh ) , that in one year intercepts dry land, is the same as thousand times of the present total world energy consumption .
Irradiation intended as solar irradiance or as power density of solar irradiation, is intercepted out of the atmosphere thanks to a surface that is perpendicular to sunlight ( it is also known as solar constant ). Irradiation is equivalent to 1353 W / m2, and during the year it is variable to ± 3 % due the elliptical earth orbit .
The following figure illustrates the irradiation development , through readings out of the atmosphere in a year :
The peak value that is detected on the earth’s surface is about 1000 W / m2 , at noon, on a summer day, clear sky, optimal sun condition.
The solar radiation that comes to the earth’s surface, a distinction can be made between direct radiation and spread radiation . Direct radiation affects the surface through a very specific and unique angle of incidence, while spread radiation affects the surface with various angles.
When the direct radiation can’t affect a surface because there is an obstacle in the middle, thanks to the spread radiation the shaded area won’t be completely obscured.
This aspect has got technical density, especially for photovoltaic installations that can also operate only through the spread radiation.
Furthermore, inclined surface can receive reflected solar radiation ( reflection ) from the land or from overwater in its front or horizontal surfaces ; such phenomenon is defined as “ albedo “ and it contributes to increase the process.
Direct radiation, spread radiation and albedo are received by a surface and the related proportion depend on certain elements :
- First of all on the weather conditions: in a cloudy day spread radiation prevails ; in a clear day , especially with dry weather , direct radiation prevails , and it can reach 90 % of the total irradiation ;
- The slope in relation to the horizontal plane of the surface : any horizontal surface will receive the higher spread radiation and the minimum reflected radiation, if there are no objects around in an upper altitude in relation to the surface’s one ;
- Presence of reflective surface : particularly the higher contributes is due to the reflection that is gave by clear surfaces . Moreover reflected radiation is higher in winter because of the reflective effect of snow and it decreases in summer months due to the effect related to the absorption by land and grass .
The slope or grade that will allow to make the stored energy utmost, could vary from location to another : changing location, the relationship between spread radiation and total radiation will vary, because increasing the grade of the surface that picks up, the component of spread radiation will be reduced and reflected component will be increased.
Practically, the optimal situation is recorded when the surface has southern exposure , and there is a rake angle that is equivalent to the site’s latitude : directing to south there will be a maximization of the filtered solar radiation that is received throughout the day and the slope is equal to the latitude that during the months of the year minimises the variation of solar energy that is filtered as a consequence of the sunlight oscillation of ± 23.5 °, compared to the perpendicular one of the harvest surface. If we name with ID the direct radiation, and with IS the spread radiation and with R albedo , then we can determine the total solar radiation that will affect on a surface :
IT = ID + IS + R
PHOTOVOLTAIC EFFECT AND THE CONVERSION OF SOLAR ENERGY INTO ELECTRICITY
Photovoltaic effect turns the direct photovoltaic conversion of solar energy into electricity through physical phenomenon in which light radiation interacts with electron of semiconductor materials.
The solar cell represents the physical object by which such phenomenon manifests itself and it is in substance a diode, that is characterized by a vast surface of several dozen cm2 .
To understand the photovoltaic effect is relevant to describe conceptually how a diode works ( p-n junction ) , and since today the crystalline silicon ( Si ) is the more used material for the creation of solar cells, silicon diode will be analysed .
The silicon atom has got 14 electron, 4 of these are valence electron, therefore they can chemically bond in pairs with other valence electron of different atoms . In a chemically pure silicon crystal, every single atom is bonded through covalent bond with other 4 silicon atoms, so ,because of chemical bonds, in the crystal there aren’t electron which are free .
In the event that several silicon atoms in the crystal would be replaced by other phosphorus atoms ( P ) that is characterized by 5 valence electron, 4 of these will be used in chemical bond with adjacent silicon atoms, while the fifth electron could be separated from the phosphorus atom through thermal energy and it will be free to move in the crystal lattice .
Similarly, silicon atoms can be replaced by boron atoms ( B ) that has got only 3 valence electron and , in this case there will be a missing electron to saturate chemical bond with adjacent silicon atoms . This missing electron will be a positive electron and it will be called “ electron hole “ .
The following picture illustrates with a graphic what has been described : in the first the structure of the crystal lattice of silicon ( Si ) is shown, in the second there is how the structure of the crystal lattice varies when is carried out a doping through phosphorus atoms ( P ) and in the last case, modification of the crystal lattice are shown after the doping with boron atoms .
In the doping through phosphorus ( P ), atoms carry free negative electric charge and material is called “ n “ type, while in the doping and therefore in the replacing of silicon atoms by boron atoms ( B ) they carry positive electric charge and material is called “ p “ type . The p-n junction ( diode ) is determined by aggregating a “ n “ type bar with a “ p “ type bar .
Material “ n “ free electron will have in their left a region in which there aren’t free electron and this will lead to a flux of such carriers to the left in order to re-stablish balance between positive and negative electric charge . Similarly, the electron hole will find in their left a region in which there aren’t electron hole and so there will be a flux of positive electric charge to the right . As a result of the activation of such spread process , on the left side there will be an excess of negative electric charge, while on the right side there will be an excess of positive electric charge .
It follows that, in the region of interface between the two materials an electric field will be determined and it will tend to increase ever more, proportionally to the fact that the electric hole and electron keep spread to the opposite sides . This process keeps going until the creating electric potential will assume a size that will stop a further spread of electron and electron hole .
When such balance will be reached, a permanent electric field in a material will be created without using external electric fields . Through these concepts, it is easier to explain the photovoltaic effect . Assume that a particle that is a sunlight ( photon ) come in the “ p “ type region of the material . If the photon have at his disposal an higher energy of the gap band , in other words the minimum energy that is needed to determine the bond cleavage in the silicon lattice, it will be absorbed and will lead to the manifestation of a pair of electron – electron hole . The released electron during this phenomenon can move to the right because of the electric potential .
Contrary, if the photon came in the “ n “ zone , the creating electron hole will move to the left .
The flux that will be activate, will lead to an accumulation of positive electric charge to the left and negative electric charge to the right . This will create an electric field that is opposite of the one that is bonded to the spread mechanism . The more will be the number of photon that will reach the junction, the more fields will tend to erase each other , until there won’t be an internal field that separate every further pair of electron – electron hole .
This is the requirement that determines the open circuit voltage of a photovoltaic cell ( see open circuit voltage of a photovoltaic modules ) . Putting electrode ( metal contacts ) on the surface of a photovoltaic cell, it is possible to use the created potential. Such flux will create an accumulation of positive electric charge + to the left and negative electric charge – to the right , creating an opposite electric field as a sign of what it is created through the spread mechanism .
In the solar cell solar radiation turns into electricity .
The solar cell is a device that is composed by a subtle slice of semiconductor material, that is often silicon ; it has a thickness that could vary from 0,25 mm to 0,35 mm, often in a square shape or with a surface of 100 cm 2 . For the production of cells , silicon is a most frequently used material and it is used in the electronic industry, where the process cycle leads to very high costs, costs that couldn’t be justified if we consider that the required degree of purity in the photovoltaic field is lower than the one which is essential for electronic .
There are also other materials that can be used to create solar cells :
- Monocrystalline silicon: energy performance 15 – 17 %
- Polycrystalline silicon : energy performance 12 – 14%
- Amorphous silicon : energy performance lower than 10 %
- Other materials : cadmium telluride, gallium arsenide, gallium and indium thallium arsenic and copper .
However, now the most used material is monocrystalline silicon, which makes record higher performance and greater prolonged duration compared to other materials that are usable for the same purpose .
The solar cell is an intermediate product in the photovoltaic industry field : it provides limited current and voltage values, if they are compared to those that are usually required in users devices, moreover cells are extremely fragile, not electrically isolated, and they haven’t a mechanical support .
Cells are therefore aggregated and assembled with the aim of building a unique structure that is called photovoltaic modules ( see also Solar Panel ).
Photovoltaic modules have a more robust structure and it is easier to handle and on them solar cells are properly placed ( see hybrid solar cell ) .
Photovoltaic modules ’ size can vary, but those that are more common have surfaces which can vary from 0,5 m2 to 1,3 m2 , usually with 36 cells that are electrically linked in series .
Photovoltaic modules have a power that can vary from 50 Wp to 150 Wp related to the type and the efficiency that characterizes the solar cells which make up modules .
The most important electric features of photovoltaic modules are :
- Peak power ( Wp) : it is the power that comes from photovoltaic modules in standard conditions of utilisation STC : Irradiation = 1000 W / m2: Temperature = 25°C ; A.M. = 1,5
- Rated current ( A ): it is the current that comes from photovoltaic modules in the work-point
- Rated voltage ( V ): it is the work-voltage of photovoltaic modules
Wp ( Watt peak ) is the size that is taken as reference of photovoltaic modules and it has the aim of expressing the electric power that comes from photovoltaic modules in standard conditions of reference ( considering standard conditions with Irradiation = 1000 W / m2 ).
WHAT IS THE PHOTOVOLTAIC SYSTEM
The photovoltaic system ( if you want see current source ) is composed by photovoltaic modules that are aggregated and linked in series and in parallel ( series and parallel circuits ) in order to reach optimal and desired operating conditions .
The base elements of the photovoltaic field are photovoltaic modules . More photovoltaic modules are mechanically assembled to each other determine the “ photovoltaic panel “ , while photovoltaic modules or panels are electrically linked in series and they allow to obtain the rated voltage of distribution, and they form the “ string “. Finally, more strings must be linked in parallel and this determinates the “ field”. United photovoltaic modules constitute the generator and they are built on a mechanical structure that is able to support the modules and it is oriented in order to maximise the solar irradiation .
The quantity of electric power that is produced by a photovoltaic system can vary in a year, in proportion to sunshine in location where the system is built and depends on latitude .
Depending on the application for which the system was designed, it must be sized observing the following criteria :
- electric load
- peak power
- possibility to connect to the power grid or not
- latitude of the site and annual average irradiation of the site where there is the photovoltaic system.
- specification of the building’s architectural type
- specification of users load’s electric type
For example it is assumed that to the latitudes of central Italy, 1 m2 of photovoltaic modules of good manufacturing on average could produce :
0,35 kWh per day during the winter period
0,65 kWh per day during the summer period
>> 180 kWh per year
A photovoltaic plant or a photovoltaic system is an aggregate of mechanic, electric and electronic components which detect / intercept and subsequently transform the available solar radiation energy, making possible to use solar energy in the form of electric energy .
Systems in this typology can be divided in two categories, regardless of the usage and size of power of themselves :
Isolated “ stand alone “ systems, by virtue of the fact that they are not connected to the electric grid, must generally and necessarily have a storage system or storage of the energy that is produced . The energy storage is needed because the photovoltaic field is in position to supply electric energy only during the day, while often the higher request of users focuses on the afternoon or in the night . During the insolation is therefore necessary to have a produced energy storage and not to use it immediately, energy that is provided to the load when there is a reduction or absence of the available one.
Configuring the plant through this method , means that the photovoltaic field is sized in order to allow the supply of the load and the charging of storage batteries ( rechargeable battery ) in the insolation hours .
In the systems connected to the grid, usually there are not storage systems because energy that is produced during the insolation hours is immediately placed in the electric grid ; on the contrary, during hours of lower insolation or without insolation, the load is powered by the grid .
If the continuity of service is considered, a system of this typology will be more reliable compared to a stand alone photovoltaic system, that after a failure, it can’t have the possibility to be powered in an alternative way . “ High reliability “ systems can be designed though an isolated system ( stand alone ) with diesel ( for example hybrid diesel – electric ) .
The aim of a grid connected system is therefore to allow the feed-in in the highest quantity of energy .
In the physic point of view the structure of a photovoltaic system, either isolated or connected to the grid, can be different ; usually 3 important blocks can be highlighted :
- photovoltaic power station
- power conditioning system
- system for data acquisition
Attention is being paid to the fact that connected to the grid systems without storage, in these cases the grid serves as power reservoir with unlimited capacity . The load is represented by connected to the grid user instead, like for a grid connected system .
WHAT ARE GRID CONNECTED PHOTOVOLTAIC PLANT
The main components of a grid connected photovoltaic plant are :
- Inverter for connecting to net
- Device for interfacing with electric grid
- Bi – directional meter for energy
The inverter is a fundamental component in the grid connected photovoltaic systems because it is able to maximise the production of electric current of the photovoltaic device, by optimising the transfer of electric energy between photovoltaic modules and load .
Inverter as a device can turn direct current which is produced by modules 12 V, 24 V, 48 V, and so on ) into alternating current ( usually 220 V ) in order to supply the load – user and / or feed the energy in the grid, with which it can work with an interchange system .
Grid connected inverters have usually got an electric type device which allow to extract full power from the photovoltaic system in every moment . The device tries to reach the maximum power point tracker ( MPPT ) and it adapts features about the production of the photovoltaic power station to the need of the load .
The inverter is also important because usually a photovoltaic system is able to give current and voltage values which vary on the basis of irradiation + temperature variables, on the contrary of the load, that usually needs constant values of voltage of supply .
Indeed, electric grid interface devices have the aim of ensuring that the form of the electric energy wave , which is fed into the grid, have got all the features that the local supplier of energy requires .
Finally, the energy meter will measure the energy that the photovoltaic system can produce during its operating period .
“ STAND ALONE “ PHOTOVOLTAIC PLANT
The main components of a stand alone or isolated photovoltaic plant are :
In this photovoltaic plant’s typology, electric energy that is produced by photovoltaic modules , is also stored in storage batteries . Through a load regulator, load is supplied by the stored energy in the batteries .
The load regulator must preserve accumulators from the load in excess due to the photovoltaic system and it must protect accumulators from an excess of load due to the use . Both situations have harmful consequences for the correct functioning and for the durability of accumulators . Since usually the power that is required by the user, it is not always equal to the intensity of solar radiation ( and consequently this affects photovoltaic plant ’s electricity production ), a portion of electric energy that is produced by the photovoltaic field must be stored in order to be used when the user will need it . This is the aim of the storage system in these plants .
Therefore, a storage system is composed by a set of rechargeable accumulators, and it is sized so as to ensure a relevant autonomy of the electric load supply . Batteries with this aim are practically accumulators of stationary typology and only in particular cases using batteries as motor fuel is permitted . It is important that batteries for photovoltaic use must have the following features :
- Self discharge low value
- Long estimated duration
- that do not require maintenance
- that can work with a high number of charging and discharging cycle
In the case of stand alone or isolated system, the aim of the inverter is to transform direct current into alternating current . The direct current is produced by the photovoltaic field and alternating current is essential for the direct supply of users .
In this case, inverters must be sized in order to supply directly the load which will be connected to it .
Obviously, the inverter with this type of plant building ( i.e. isolated or stand alone plants ) doesn’t represent a component with a compulsory presence ; it is possible to supply directly the load in direct current and with low voltage .
WHICH ARE THE CRITERIA FOR SIZING A PHOTOVOLTAIC PLANT
There are description of the phases for sizing a photovoltaic plant and indication for designing a complete plant .
VERIFY THE SITE ’S COMPETENCE
- Quantify presence of shadows ( vegetation, heights , buildings )
- Morning mists
This information allow to determine the photovoltaic system ’s placement, optimising their exposure to the South, higher inclination on the horizontal plane, support structures and their features .
HOW TO QUANTIFY THE DAILY NEED OF ENERGY
Energy = Power for the time of use
Isolated or grid connected utilisation consumption will be supplied through the photovoltaic plant and will be catalogued in terms of daily required energy .
- 2 15 W lamps must be supplied 5 hours per day
- 1 60 W CRT must be supplied 3 hours per day
Total energy that is daily needed = 2 x 15 W x 5 hours per day + 1 x 60 W x 3 hours per day = 330 Wh per day
SELECTION OF THE BEST MODULES’ INCLINATION
HOW TO CALCULATE A PHOTOVOLTAIC SYSTEM’S POWER PEAK
Electric energy that is produced by photovoltaic modules is linearly proportional to the solar radiation which affects on the solar modules ’ surface ; the calculation can be made referring to the information about the site ’s solar irradiation .
A calculation method that is frequently used , is to detect EQUIVALENT HOURS of the site through appropriate tables and the hours are considered with the optimal photovoltaic modules’ inclination . “ EQUIVALENT HOUR “ is the period of time in which solar irradiation reaches an equivalent value of 1000 W / m2 . In a location of centre Italy, the average value related to 12 months of such indicator, the value can be 3, assuming a modules’ inclination of 45° .
For the calculation of the dimensioning of a photovoltaic plant, this method is used to identify the quantity of daily energy that is produced by photovoltaic modules . According to this method and knowing the “ monthly equivalent hour of the site “, it is possible to determine the peak power of our photovoltaic system with the following method :
Photovoltaic system’s peak power Kwp = daily need of Equivalent Hours energy
IDENTIFICATION AND ASSESSMENTS OF PLANT’S LOSSES
It is important to consider losses or voltage drops which are introduced by components that constitute the photovoltaic plant ( inverter, voltage regulator , batteries , cable connections and so on ).
Knowing that total losses of the photovoltaic plant are 30 %, it will be necessary to increase the Kwp ( peak power ) of the same percentage in the photovoltaic system .
CALCULATION OF AN INVERTER POWER
The power of an inverter is calculated in a different way according to grid connected or isolated ( stand alone ) plants . In the case of a grid connected plant , the choice of inverter is based on the feature of the photovoltaic field : when the power of the photovoltaic system is fixed and therefore the number of photovoltaic modules as well, the typology of usable inverter is identifiable .
For an isolated plant, the maximum total power connected to the inverter will be calculated . For example , the case that was used before to calculate daily energy need :
Total power = 2 x 15 W + 1 x 60 W = 90 W
Substantially, an inverter of rated power higher than 90 W must be used .
Depending on the waveform that is produced, to choose the inverter for the isolated stand alone plants , different types of inverters can be used :
- pure sine wave inverters : they can reproduce a waveform that is practically the same as the grid one and they allow to supply any load typology
- trapezoidal wave and square wave inverters : they could not supply correctly, for example electronic type loads .
SIZE STORAGE SYSTEM FOR STAND ALONE ISOLATED PLANTS
If low levels of sun occur, photovoltaic plant would have lower productions than those that are achievable in optimal days of sun, therefore when this occurs the storage can be sized in order to ensure a certain load supply, for a certain period of time ( maximum number of consecutive days), in which there is absence of sun .
COST OF A PHOTOVOLTAIC PLANT
The investment in photovoltaic plants implies a significant use of capital in the first phase and low expenses for parks maintenance .
Analysing all the economical and financial aspects related to a photovoltaic plant is quite complex, however there are some elements which must be considered :
- Every photovoltaic plant and installation needs to be analysed in its reference framework ( legislation, local condition . Solar irradiation level, available areas and so on ).
- It is fundamental to refer to the energy value that is produced and not to focus on the energy cost in order to operate correctly ; this because from a qualitative point of view, the energy that is produced through photovoltaic solar source is not the same compared to energy traditional sources, both for environmental impact and intermittent of produced energy and so on .
- Photovoltaic system’s life time is about 25 years now, even though some manufacturers give assurance for longer periods .
- Difficult links to the grid, for situation like mountain hut or isolated houses in low urbanized areas and so on .
There are cases where the initial investment is amortised ( see amortisation ) for the cost of user electrification that is higher than the cost for the installation the photovoltaic solar plant .
Usually for a photovoltaic plant there is a cost per kWh that is a higher product than the cost per kWh if is bought from the network ; as a result it is better to install a photovoltaic plant in line with present incentive forms ( Feed-in tariff ). A cost per kWh that is produced by a photovoltaic plant it can be compared to the kWh that is bought in network, if through financial types of contribution in high percentage .
HISTORICAL EXAMPLE TO UNDERSTAND THE APPROACH BETWEEN ITALY AND FOREIGN COUNTRY :
In 2001 it was created a national project called “ Tetti Fotovoltaici “ in Italy; it was characterized by various critical points that are inherent in the photovoltaic solar field development and they are :
- Advertising campaigns and information were not clear and sometimes they were wrong by responsible bodies
- Number of limited funding ( about 30 / 40 fundable projects ) if they are compared to the total demand that were received in each region
- Need to advance money by customers to buy the photovoltaic plant
- Presence of a maximum limit for the cost for the plant ; this has favoured the spread of low quality plants
- Absence of indications for the quality of modules that are used in terms of performance, efficiency and so on
- Absence of refunds of kWh that were produced by photovoltaic plant, only an adjustment between electric energy production and consumption
- Uncertainty for the effective final typal approval of photovoltaic plant .
On the contrary an elementary but effective project for the promotion of the photovoltaic solar field in Germany is given, and it was created in 2000 in which :
- there were not non – refundable contribution
- there were subsidised rate funding lasting 10 years
- there were facilities connected with the electric energy that was produced by the photovoltaic plant .
Such programme allowed to create photovoltaic plants as investment, to realise high efficiency and quality plants, to obtain the highest production possible and users were stimulated to do effective maintenance actions on time .
Environmental impact in the solar renewable is low or it doesn’t exist, because of the absence of the release of polluting substances in the environment ( air, water, see pollution ). There is a reduction in gas that are responsible of the feared greenhouse and of the phenomenon of acid rain .
The photovoltaic conversion from solar energy into electric energy represents the renewable type source which is more environmentally friendly .
Photovoltaic solar plants don’t emit polluting materials, vibration and since they are modular, they go along with the site’s geomorphology where they are installed ; finally they can produce energy near electric loads, so succeeding to prevent transmission losses .
By the way, the environmental impact is not zero : some problems remain and there are limited typology of environmental impact that affect the approval or acceptance of plants and they are the following :
- productive process of components and the pollution that comes from it
- usage and saturation of areas in territories which don’t allow other uses
- sometimes a significant visual impact ( visual pollution )
- impact on fauna and flora, i.e. on the local climate .
As regard to the pollution in the components production phase . The choice of raw materials can reduce the phenomenon, for the rest emission that come from productive process are the function of more or less advanced technology that is used during the production phase . The most used photovoltaic plants and photovoltaic systems are based on silicon ( a chemical element that is widespread on the earth’s crust ) both in the crystal form, poly – crystal and amorphous form .
The production process doesn’t provoke an excessive use of harmful or polluting substances and in is important to say that in the photovoltaic market, a part of the silicon comes from the reuse of waste in the electronic industry .
It must be highlighted that some typology of solar cell may involve potential risks in case of fire, because toxic gasses can form after a combustion ; obviously when photovoltaic panels can be no more used , they are properly disposed ( photovoltaic waste ) through adequate system of photovoltaic panels recycling . Photovoltaic parks installation and therefore the need of space and territory depends on how the photovoltaic is used : decentralised or centralised mode in big plants .
In the first case and in the decentralised mode, the used part of territory is reduced because the photovoltaic plant is installed in surfaces that were already removed from the natural environment, for example roofs, building ’s facades or balconies of existing buildings, car parks and their structure, service areas near cliffs, dangerous places and sides of the road etc. The expansion potential for the decentralised photovoltaic and photovoltaic systems is large, and the degree of penetration and development is connected with a substantial costs reduction .
Analysing the second case, i.e. centralised photovoltaic production plants ( mega watt ) , where the energy need is, the efficiency of modules conversion and site’s insolation are optimised and they need significant territory extensions in order to provide overall an appreciable contribute .
Reasons of aesthetic type led to a failure of some projects and photovoltaic systems, where a strong visual impact depends on the size of the park that affected heavily the territory ; this impact is very reduced in the decentralised use, for example roofs and facades .
Big or medium sized photovoltaic plants will have a larger visual impact that amplifies in the case of beautiful countryside .
Another problem that is possible to find concerns the reflecting surfaces and the disturbance that is connected with enormous surfaces near residential areas, roads etc., and with the actions that are necessary in order to mitigate the effects modifying the slope or building appropriate protective shields through arboreal elements or shrubs, without incurring to create shadow zones in the photovoltaic field ( see ENEA research ) .
In the decentralised use of photovoltaic solar systems the impact on flora and fauna related to the limited subtracted ground is negligible since the absence of noise and vibration .
When photovoltaic panels subtract solar radiation to the environment, aspect that could involve light modification on the local microclimate, is appropriate to bear in mind that only about 10 % of energy of the sun that affects for time unit on the surfaces of the photovoltaic field, will be converted and transported to another place as electric energy while the remaining part will be reflected or will go through modules .
In the multitude of territorial institutional and social contexts, and in the past experiences turns out that a soft technology for the environment to, as well as solar photovoltaic energy, is not exempt from environmental impact that can create difficulties in the population’s acceptance of green projects and they are useful from the energetic point of view .
The size of a solar plant and the impact that is determined in the solar photovoltaic are infinitely lower than the older energy technologies ( energy from coal, nuclear energy etc. ), however they are enough to create position and opposition that are difficult to pass, therefore, the identification of the right site, the design of the plant and the realisation of the authorisation procedure will give better results if appropriate evaluation and consideration on the environmental impact will be made, in advance with accuracy and involving social parts .
PROJECT AND SIZING OF A PHOTOVOLTAIC PLANT
PRELIMINARY ANALYSIS : it is based on some elements such as economic benefit, possible urban restrictions, presence or absence of incentives, costs for the request for a point of connection to the institution which deals with the grid .
FINAL PLANNING : it includes authorisation, final planning as built, technical documentation must be finished and sent for the request to put the photovoltaic plant in the grid .
REQUESTED DATA FOR THE PRELIMINARY ANALYSIS
A correct data collection is needed in order to start a feasibility study : there must be drawings and photos in which there is the orientation of the site where the park will be built, data related to electric energy consumption and supply ( if there it is ), information about the structure where the photovoltaic plant will be installed ( permissible load for the coverage ).
HOW TO DO THE CALCULATION OF THE PHOTOVOLTAIC PLANT’S SIZE IN A PRELIMINARY PHASE
The space necessary for realise a photovoltaic plant depend on the site where the photovoltaic must be installed, on the technology and therefore the efficiency of the chosen photovoltaic modules .
Sometime high efficiency and value photovoltaic modules must be used because of the high consumption and the small available space ( see CIGS modules )
Speaking of energy, the grid parity represents the point when the electric energy that is produced through the plant ( that are supplied by renewable energy sources ), is characterized by having the same price as the energy that is produced through other sources of traditional or conventional energy, such as methods that use fossil sources or different sources, for example the nuclear energy .
In the Italian energy market, especially in the last years and in the photovoltaic area, it was recorded a phenomenon of the spread of investment in this area thanks to these incentives . When the incentive system through energy accounts ( on the base of the incentives for the electric production through the solar source in July 2013 ), the Grid Parity has became more popular, in terms of “ parity “ between cost of electric energy that is produced by a photovoltaic plant and cost for buying the energy from the grid .
Following the enactment of the Strategia Energetica Nazionale SEN 2017 by MISE ( Ministry of Economic Development in Italy ), there are important aims as regards to the photovoltaic production in the area of electric energy production mix : 72 Twh until 2030, compared to 24,8 Twh that were produced in 2017 . The concept of market parity as grid parity’s evolution is taking off .
GRID PARITY AND MARKET PARITY
A study made by Department of electrical engineering in the University of Padova, highlights how in Italy the grid parity was achieved in 2013 : therefore the price per kilowatt – hour for cars ( the consumption obtained by photovoltaic panels is the same as the price of the energy that is possible to buy from the electric grid ).
According to an other study made by a Spin off in the University of Roma Tor Vergata, some definition related to the photovoltaic grid parity have increase and this concept is developing :
- Observability : intended as competitiveness as cost of generation of renewable Kwh
- Reachability : intended as competitiveness related to the profitability of the investment .
According to the terminology in use, a photovoltaic plant in the grid parity means production of electric energy through solar sources and such production is obtained without incentives, i.e. through an economic return that is equivalent to the sum of :
- a proportion of the electric energy that is switched with the grid and whose has got an economic value of Dedicated Withdrawal or Net metering
- no cost of acquisition for the electric energy as regard to the self – consumed quota ( statistical ratio Solar Photovoltaic GSE )
Trade arrangements managed by GSE, can include a modes of operation of the total or partial self-consumption plant, on the basis of the plant’s power class in Kwp and of the producer costumer ’s energy -intensive profile ( new definition of energy – intensive companies of Anima ) that has got responsibility for the photovoltaic plant .
A cost of generation of photovoltaic kWh ( Levelised Energy Cost ) is mapped to the photovoltaic plant in the grid parity, as well as a IRR ( Internal Rate of Return ) of the investment that is involved in the plant’s installation ; It must be compared to the benchmark values of IRR, with the aim to understand if it is appropriate the investment ’s risk and the obtaining of the accessibility condition and therefore the obtaining of the Grid Parity .
Producing electric energy through solar photovoltaic sources without incentives and without self-consumption leads to the concept of market parity or parity generation . Chile is an example, but there are other examples in the world where the photovoltaic wins without incentives on the conventional plants of coal energy or energy from other sources according to the data related to the electric market . The discriminatory is the high cost of electric energy together with the strong solar irradiation . The market parity is made when electric energy is produced through solar photovoltaic sources but without any incentive .
The market parity is obtained thanks to multi megawatt photovoltaic plants that are connected to the distribution grid in medium – voltage, or utility scale photovoltaic plants that are connected to the transmission grid in high – voltage .
To obtain the economic value in the market parity, the value of the official electric energy must be sought in the power exchange GME . Market parity represents the Trade Off between :
- generation cost per photovoltaic kWh LCOE and
- price in the electric market of electric energy
The electric energy is produced and then is fed into the grid and is commercially levied through the “ indirect withdrawal “ from the GSE, and it has got a value for the zonal time price .
In an alternative way, this electric energy can be sold directly in the market of electric energy of the power exchange GME or it can be bought through a trader through two – year contracts for a fixed price ( 48 € / Mwh in 2017 ).
A group of researchers in the Polytechnic of Milan, thanks to a study about this concept, they highlight how the expression grid parity is usually intended as parity between electric energy production cost made by a photovoltaic plant and the cost for the buying of the energy from the grid .
However, usually “ grid parity “ is when it is convenient to invest in a photovoltaic plant, both from a economic point of view and good profitability of the investment, where there aren’t incentives . Speaking of photovoltaic in Italy, the grid parity represents a reachable purpose, with substantial difference and therefore a higher or lower convenience of the investment, depending on the typology of plant, locality and usage of the energy that is produced. There are studies that summarises the differences between the grid parity model and market parity .
Authorisation for photovoltaic plants
Depending on cases, the authorisation to build photovoltaic plants in Italy starts with a simply communication of a prior installation to the municipality, however sometimes the process can become more elaborate and bureaucratic : it depends on single regional rules that have to regulate permission according to certain criteria, which must necessarily adhere to the national guidance .
Furthermore, the area in which the plant will be installed and the size of the photovoltaic plant affect this process as well .
For each photovoltaic plant type there is a specific authorisation, both for a photovoltaic plant that is installed on a roof a building and for the one that is installed on the ground and so on .
First of all it is necessary to contact the technical office of the municipality of the territory in which the plant will be installed, however the Province ( Provinces list ) has got competence and responsibility for the big plants or for photovoltaic plant that are next to protected areas, in some case the responsibilities belong to the Region ( Regions list ) or to the Superintendence ( superintendence list and Ministry of Cultural Heritage and Activities ).
AUTHORISATION OF PHOTOVOLTAIC PLANTS
Except for the big photovoltaic plant on the ground or next to protected areas ( official list of protected natural areas ), where the process can become complex, usually the prior communication to the Municipality is enough in order to start working on plants such as domestic plants or small industrial plants . Since November 2015 an additional simplification of the bureaucracy has been in force : it is a simplified procedure to build a connection and start working on small photovoltaic plants on the buildings’ roof . This procedure allows to use a Modulo Unico ( a type of model ) in order to comply with obligations under the relevant laws : municipal authorisation , request application to Enel / Terna in order to connect with the grid, dispatch of practice for Net Metering to GSE . Link to the decree of simplification of authorisation for residential photovoltaic plants
COMMUNICATION TO THE MUNICIPALITY FOR THE AUTHORISATION
Simple authorisation title, it is the legislation for plants assimilated to activities of free building ( denuncia di inizio attività in edilizia ) . It is sent with telematics in some municipality and it is a prior communication to the municipality of a determinate territory, there is a tacit consent , and it is actually a communication of start of work . Contact point to refer to : Technical Office of the related Municipality .
When it is applied :
It is a request that is applied to plants which cannot benefit from the unique procedura autorizzativa semplificata ( a procedure ) under the power of 20 KW ; the communication to the municipality is suitable for small plants on the roof where the simplified procedure is not applied . The prior communication is enough for photovoltaic plants that are on the roof or are integrated in the roof with same inclination and equal to the to brim’s orientation where they will be installed ; a modification of the building ’s template that houses photovoltaic panels mustn’t be verified . Criteria are considered valid only if plants are not installed in areas subjected to protection or constraints of the legal code of cultural heritage and landscape . Otherwise other procedures are compulsory and the competence could move from municipality, province, region to the superintendence in order to grant authorisation .
The prior communication to the municipality is also a suitable authorisation for photovoltaic plants and from renewable sources that are compatible with the “ Net Metering” . Following there are some guideline :
Plants must not :
- provoke an alteration of the size of a building
- provoke an alteration of the surface of a buildings
- alter the intended use of a building
- modify the number of building units inside the building
- involve an increase of the number of urban parameters ( building codes )
- affect the structural parts of a building
- be on buildings that are in historic centres ( A area General Urban Development )
The prior communication to a determinate municipality as single authorisation typology, requires that the holder of the plant that will be built, has got the full legal participation ( Property ) on areas or on goods subjected to works that will be carried out in order to build the plant .
When photovoltaic plants that will be installed are between 20 kW and 50 MW or in the case in which the proposer has not the full ownership on the areas or on the buildings, it will be necessary the Autorizzazione Unica AU ( A type of an authorisation ) and the competence will move from municipality, province or region .
PROCEDURA AUTORIZZATIVA SEMPLIFICATA AND MODELLO UNICO
The contact point for the granting of the authorisation is only the system operator ( Enel / Terna ) . Enel Distribution becomes the single mediator for the applicant for the handling of the case .
The Procedura Autorizzativa Semplificata was created in november 2015 in order to speed up the authorisation process for the installation of small photovoltaic plant on the roof . The authorisation process as bureaucracy involves exclusively the compilation and the next dispatch ( in 2 phases ) of a Modello Unico .
This “ Modello Unico” is accessible through telematics from the producer of the system operator on internet, in this case Enel Distribution . Through the gateway a first part of the model can be made out before the start of works and then a second section when works are finished .
Through this procedure, in 2 phases, the municipality is warned of the “ start of work “ and the request of installation of photovoltaic plant is sent to Enel, and a copy of the instance of request in order to access the net metering will be sent to GSE . The Modello Unico works as authorisation function for some photovoltaic plants . The Modello Unico has the big lead : the applicant can interface only with Enel in order to handle administrative and bureaucratic aspects and it permits the applicant to proceed to the presentation with different timing, 2 modules complying the authorisation request in order to create and install the photovoltaic plant .
The first phase of the model, before the start of works, includes the communication of “ start of works “ to the municipality, cadastral data of the plant ( visura cadastral ) and biographical data of the applicant . The second phase of the model, when works are finished, includes the communication of “end of works”, technical data of the plant, declaration of conformity and instance of start Net Metering .
It is possible to adhere to the simplified procedure and it concerns about new small domestic plants and small industrial plants . These are the requirements for the accession to the simplified process for those who want to install a photovoltaic plant :
- connection to a point of withdrawal in existing low voltage, where other plants of electric production are not connected
- lower or equal power to the power in the withdrawal point
- plant until 20 KW of power
- plant made on the roof
- connection to the grid through “ Net Metering “ method with GSE
Substantially the typology of plants which can be installed : new plants on the roof of houses, small companies, laboratories, sheds and condos .
LINKS ON PHOTOVOLTAIC FIELD :
PV, Solar Photovoltaic
Photovoltaic Geographical Information System ( PVGIS )
TICA ( testo integrato connessioni attive )
Valutazione Impatto Ambientale V.I.A.
Autorizzazioni Fotovoltaico ( AU autorizzazione unica, PAS procedura abilitativa semplificata )
Developer of photovoltaic parks
Green Field Investment
Attualizzazione ( Discount )
Unit of measurement : Power ( Watt, Megawatt MW, Watt peak, Megawatt Peak MWp ), Surface ( Hectare )
Technical terms related to land : CDU ( Certificato di Destinazione Urbanistica ), Visura Cadastral for lands , Particelle Lotti, Agricultural soil Land typology
Google Earth ( Localizzazione terreni )
Enel , Terna ( Handler of electricity grid )
GSE ( Handler of energetic services )
Professional association : Agronomists, Surveyors, Engineers, Architects, Experts , Professional office
NDA Accordo di Non Divulgazione ( Non Disclosure Agreement )
Translated by : Matteo Aristei