Sončna energija je najbolj perspektivna oblika okolju prijazne energije. Sonce ni od nikogar, ne bo ga zmanjkalo in ne izstavlja računov. Stroški so le pri začetni investiciji, zato si je z naložbo v sončno elektrarno mogoče ustvariti dolgoročno zagotovljen prihodek. Na takšno naložbo je mogoče gledati kot na naložbo za pokojninsko rento. Investicija se povrne in boste ustvarili dobiček, vendar so tu še nefinančne koristi, ki jih investicija nudi. To je ustvarjenje čiste energije, zmanjševanje emisije C02, povečanje vrednosti objekta in ugled v javnosti… Investicija do 50 W inštalirane moči se povrne v povprečju v 8 – 9 letih. Popolno delovanje najboljših osnovnih elementov sončne elektrarne traja 20 let, z intenzivnostjo 80% pa moduli delujejo še nadaljnjih 10 let.

Kakšna je ekonomika naložbe v sončno elektrarno?
Ekonomika investicije je v tem, da lastnik sončne elektrarne pridobljeno elektriko ne uporabi zase, ampak jo po ločenem števcu oddaja v omrežje. Cena, po kateri jo oddaja, je približno štirikrat višja od tiste, ki jo plačuje kot uporabnik. Razliko v ceni namreč subvencionira država. Če lastnik elektriko uporablja samo za lastno oskrbo, je upravičen le do 30 odstotkov premije. Vsako pridelano kilovatno uro lastnik elektrarne na podlagi pogodbe proda elektrodistribucijskemu podjetju po ceni, ki je sestavljena iz letne premije in tržne cene. Ocenjena odkupna cena pri postavitvi na streho tako znaša cca. 0.41546 za kWh. Pri tem predstavlja enotna letna premija (subvencionirana) 0,35546 kWh + tržna cena, ki je okrog 0,06 na kWh (odvisna je od končnega dogovora z odjemalcem električne energije). Odkupna cena ni stalna. Po petih letih se zniža za pet odstotkov, po 10 letih pa za deset, vendar je v pripravi bolj stimulativna zakonodaja. Kot kvalificiran proizvajalec električne energije lastnik elektrarne podpiše pogodbo z elektrodistributerjem za deset let. V najslabšem primeru bo lastnik sončne elektrarne po poteku pogodbe lahko elektriko prodajal po tržni ceni, ki se bo še precej povečala. K ekonomiki pa svoje prispeva tudi vsakoletni razpis Eko sklada za pridobitev nepovratnih sredstev za nakup in montažo solarnih sistemov, ki je trenutno tudi še odprt.

Recimo, da boste postavili elektrarno na obstoječi objekt ali zemljišče v vaši lasti. Postavite jo lahko na streho, v streho namesto kritine, na fasado, kot senčilo, kot streho zimskega vrta, kot pokrit parkirni prostor ali kot samostojen sistem na zemljišču. Površina sončne elektrarne naj sprejme čim več svetlobe, kajti več ko bo svetlobe, več je bo sistem lahko pretvoril v električno energijo. V prvem koraku lahko sami okvirno preverite, kje bi bilo elektrarno smiselno postaviti, tako da poiščete južne lege in ugotovite potencialno senčenje iz okoljskih ovir, kot so drevesa, drogovi, sosednje stavbe, dimniki, zračniki, hribi… Na ravnih strehah je mogoče postaviti ustrezno dvignjeno konstrukcijo. Pri poševnih strehah so najprimernejše tiste s slemenom v smeri vzhod-zahod in z naklonom od 30 do 35 stopinj. Pri drugih legah pa je treba izračunati, kakšen bo odmik od lege za idealno proizvodnjo. Pomagate si lahko tudi tako, da spremljate pot sonca v različnih delih dneva, v pomoč pa so lahko tudi fotografije senc ob različnih urah. To bo pomemben podatek pri oceni dejansko pridobljene energije na vašem objektu. Na zemljišču so pomembni lega, senčenje in tudi status zemljišča – brez težav boste postavili elektrarno na gradbeni parceli, težave s pridobivanjem dovoljenj pa boste imeli na kmetijskih zemljiščih.

Tankoplastni moduli so uporabni za investitorje, ki imajo na voljo velike površine strehe in jim ni pomembna moč, ki jo bodo pridobili na takšni površini. Izkoristki takšnih modulov na površino so namreč majhni, poleg tega je zaradi velike površine ustrezno večji tudi strošek vodnikov in pomožnega materiala. Monokristalni in polikristalni moduli so zaradi zahtevnejše tehnologije izdelave navadno dražji, vendar vrsta modula še ne pove dovolj. Pomembnejši je podatek o nazivni moči, prostorskem izkoristku in jamstvu na dolgoročno delovanje ter drugi tehnični podatki. Načelno imajo monokristalni moduli večje izkoristke, vendar je treba za vsak objekt poiskati optimalne module in druge komponente ter doseči optimalno razmerje med vloženim kapitalom in pričakovanimi prihodki. Nizka cena modulov še zdaleč ne pomeni, da bo zato dolgoročno ekonomika investicije ugodna ampak je certificirana kakovost tu odločilnega pomena.

Na kaj je potrebno biti še posebej pozoren pri nakupu posameznih elementov?
Osnovo sončne elektrarne predstavljajo fotonapetostni moduli. Nadalje pa so pomembne komponente še razsmerniki, elektroinstalacije, nadzorni sistem, pritrdilna konstrukcija in priklop celotnega sistema na distribucijsko omrežje. Pri tem kje potrebna pravilna zasnova ter ustrezno in natančno izbrana tehnologija, saj smo že v začetku postavljeni pred dejstvo, da se moramo odločiti, kakšni tehnologiji in kateremu proizvajalcu zaupati. Zelo pozoren je treba biti na kakovost vgrajenih komponent, saj je pričakovana življenjska doba sončne elektrarne 30 let in v tem času se vam bo višja začetna cena zaradi kakovostnejših komponent več kot obrestovala. Nasprotno pa lahko začetni prihranek zaradi cenejših modulov, razsmernikov, podkonstrukcij in nadzornega sistema v obdobju 30 let pomeni nekajkrat večjo izgubo od začetnega prihranka. Obstaja lahko zelo veliko tveganje, da na daljši rok ne boste dobili moči, ki ste jo kupili, oziroma, da bo vaša sončna elektrarna po nekaj letih bistveno slabše delovala, kot bi morala. Pojavijo pa se lahko tudi težave pri uveljavljanju garancij. Zato najcenejša rešitev ni nujno najboljša rešitev!

Število ponudnikov opreme za sončno elektrarno je v zadnjem letih izjemno poraslo. Vendar je med njimi večina takšnih, ki imajo enega zaposlenega ali pa so to podjetja, ki to opremo vključujejo v svojo prodajo zgolj zaradi trenutne popularnosti fotovoltaike in nimajo za to ne primernega strokovnega znanja, ne izkušenj in ne referenc.

AKTUALNO! Odkupne cene proizvedene električne energije v sončnih elektrarnah postavljenih v letu 2012

Odkupne cene proizvedene električne energije v sončnih elektrarnah postavljenih v letu 2012

23.12.2011

ZO – zagotovljen odkup
OP – obratovalna podpora

Pravno obvestilo

Dokument predstavlja NEURADNI izračun višin podpor za leto 2012. Uradni izračun se opravi na podlagi veljavnih predpisov ter pravnomočne odločbe o dodelitvi podpore, ki jo na podlagi vloge upravičenca izda Javna Agencija RS za energijo.

Sol navitas d.o.o. se bo trudil, da zagotovi najbolj točne in najnovejše podatke, vendar pa Sol navitas d.o.o. ne prevzema nobenih garancij o njihovi točnosti. Vsi uporabniki vso objavljeno vsebino uporabljajo na lastno odgovornost.

ODKUPNE CENE 2012

Monocrystalline Silicon Cells:
Made using cells saw-cut from a single cylindrical crystal of silicon, this is the most efficient of the photovoltaic (PV) technologies. The principle advantage of monocrystalline cells are their high efficiencies, typically around 15%, although the manufacturing process required to produce monocrystalline silicon is complicated, resulting in slightly higher costs than other technologies.

Multicrystalline Silicon Cells:
Made from cells cut from an ingot of melted and recrystallised silicon. In the manufacturing process, molten silicon is cast into ingots of polycrystalline silicon, these ingots are then saw-cut into very thin wafers and assembled into complete cells. Multicrystalline cells are cheaper to produce than monocrystalline ones, due to the simpler manufacturing process. However, they tend to be slightly less efficient, with average efficiencies of around 12%., creating a granular texture

Thick-film Silicon:
Another multicrystalline technology where the silicon is deposited in a continuous process onto a base material giving a fine grained, sparkling appearance. Like all crystalline PV, this is encapsulated in a transparent insulating polymer with a tempered glass cover and usually bound into a strong aluminium frame.

Amorphous Silicon:
Amorphous silicon cells are composed of silicon atoms in a thin homogenous layer rather than a crystal structure. Amorphous silicon absorbs light more effectively than crystalline silicon, so the cells can be thinner. For this reason, amorphous silicon is also known as a “thin film” PV technology. Amorphous silicon can be deposited on a wide range of substrates, both rigid and flexible, which makes it ideal for curved surfaces and “fold-away” modules. Amorphous cells are, however, less efficient than crystalline based cells, with typical efficiencies of around 6%, but they are easier and therefore cheaper to produce. Their low cost makes them ideally suited for many applications where high efficiency is not required and low cost is important.

Other Thin Films:
A number of other promising materials such as cadmium telluride (CdTe) and copper indium diselenide (CIS) are now being used for PV modules. The attraction of these technologies is that they can be manufactured by relatively inexpensive industrial processes, certainly in comparison to crystalline silicon technologies, yet they typically offer higher module efficiencies than amorphous silicon. New technologies based on the photosynthesis process are not yet on the market.

Solar electricity is created by using Photovoltaic (PV) technologyby converting solar energy into solar electricity from sunlight. Photovoltaic systems use sunlight to power ordinary electrical equipment, for example, household appliances, computers and lighting. The photovoltaic (PV) process converts free solar energy – the most abundant energy source on the planet – directly into solar power. Note that this is not the familiar “passive” or Solar electricity thermal technology used for space heating and hot water production.

A PV cell consists of two or more thin layers of semi-conducting material, most commonly silicon. When the silicon is exposed to light, electrical charges are generated and this can be conducted away by metal contacts as direct current (DC). The electrical output from a single cell is small, so multiple cells are connected together and encapsulated (usually behind glass) to form a module (sometimes referred to as a “panel”). The PV module is the principle building block of a PV system and any number of modules can be connected together to give the desired electrical output.

PV equipment has no moving parts and as a result requires minimal maintenance. It generates solar electricity without producing emissions of greenhouse or any other gases, and its operation is virtually silent.

What is PV power used for?

PV systems supply solar electricity to many applications in the UK, ranging from systems supplying power to city buildings (which are also connected to the normal local solar power network) to systems supplying power to garden lights or to remote telecom relay stations.

The main area of interest in the UK today is grid connect PV systems. These systems are connected to the local solar electricity network. This means that during the day, the solar electricity generated by the PV system can either be used immediately (which is normal for systems installed on offices and other commercial buildings), or can be sold to one of the electricity supply companies (which is more common for domestic systems where the occupier may be out during the day). In the evening, when the electrical system is unable to provide the electricity required, power can be bought back from the network. In effect, the grid is acting as a Solar electricity energy storage system, which means the PV system does not need to include battery storage.

Grid connect PV systems are often integrated into buildings. PV technology is ideally suited to use on buildings, providing pollution and noise-free solar power without using extra space. The use of photovoltaics on buildings has grown substantially in the UK over the last few years, with many impressive examples already in operation.

PV systems can be incorporated into buildings in various ways. Sloping rooftops are an ideal site, where modules can simply be mounted using frames. Photovoltaic systems can also be incorporated into the actual building fabric, for example PV roof tiles are now available which can be fitted as would standard tiles. In addition, PV can also be incorporated as building facades, canopies and sky lights amongst many other applications.

Stand-alone photovoltaic systems have been used for many years in the UK to supply solar electricity to applications where grid solar power supplies are unavailable or difficult to connect to. Examples include monitoring stations, radio repeater stations, telephone kiosks and street lighting. There is also a substantial market for PV technology in the leisure industry, with battery chargers for boats and caravans, as well as for powering garden equipment such as solar electricity fountains. These systems normally use batteries to store the solar power, if larger amounts are required they can be combined with another source of power – a biomass generator, a wind turbine or diesel generator to form a hybrid power supply system.

PV technology is also widely used in the developing world. The technology is particularly suited here, where electricity grids are unreliable or non-existent, with remote locations often making PV power supply the most economic option. In addition, many developing countries have high solar radiation levels year round.

Electrical transformers are used to “transform” voltage from one level to another, usually from a higher voltage to a lower voltage. They do this by applying the principle of magnetic induction between coils to convert voltage and/or current levels.

In this way, electrical transformers are a passive device which transforms alternating current (otherwise known as “AC”) electric energy from one circuit into another through electromagnetic induction. An electrical transformer normally consists of a ferromagnetic core and two or more coils called “windings”. A changing current in the primary winding creates an alternating magnetic field in the core. In turn, the core multiplies this field and couples the most of the flux through the secondary tranformer windings. This in turn induces alternating voltage (or emf) in each of the secondary coils.

Electrical transformers can be configured as either a single-phase or a three-phase configuration. There are several important specifications to specify when searching for electrical transformers. These include: maximum secondary voltage rating, maximum secondary current rating, maximum power rating, and output type. An electrical transformer may provide more than one secondary voltage value. The Rated Power is the sum of the VA (Volts x Amps) for all of the secondary windings. Output choices include AC or DC. For Alternating Current waveform output, voltage the values are typically given in RMS values. Consult manufacturer for waveform options. For direct current secondary voltage output, consult manufacturer for type of rectification.

Cores can be constructed as either a toroidal or laminated. Toroidal units typically have copper wire wrapped around a cylindrical core so the magnetic flux, which occurs within the coil, doesn’t leak out, the coil efficiency is good, and the magnetic flux has little influence on other components. Laminated refers to the laminated-steel cores. These steel laminations are insulated with a nonconducting material, such as varnish, and then formed into a core that reduce electrical losses. There are many types. These include autotransformer, control, current, distribution, general-purpose, instrument, isolation, potential (voltage), power, step-up, and step-down. Mountings include chassis mount, dish or disk mount, enclosure or free standing, h frame, and PCB mount.

Razsmerniki pretvarjajo enosmerni tok, ki ga proizvedejo solarne celice v solarnih modulih v izmenični, z omrežjem ujemajoči se električni tok. So drugi najpomembnejši del sončne elektrarne in predstavljajo 7 do 9 % vrednosti sončne elektrarne po sistemu izgradnja na ključ. Najpomembnejša je učinkovitost  razsmernika (evropska učinkovitost 96% ali več), saj brez učinkovitosti pri razsmerniku vse ostalo sploh ni pomembno. Seveda je potrebno pogledati garancije, proizvajalca, da se nam ne bo razsmernik vsake toliko časa pokvaril.
Učinkovitost razsmernikov
Učinkovitost razsmernikov se trenutno giblje med 91 in 97 %. Vsak razsmernik ima podatek o maksimalni učinkovitosti, ki pa se nanaša na “laboratorijske” testne pogoje in je v praksi ni mogoče doseči. Bolj realna je evropska učinkovitost, ki je nekoliko nižja od maksimalne, ker bolj realno upošteva pogoje, ki veljajo v praksi v Evropi.  Zato vedno zahtevajte podatke o evropski učinkovitosti razsmernikov. Podatki o največjih številih letno proizvedenih kWh električne energije iz 1 kW sončne elektrarne, so dobljeni z razsmerniki učinkovitosti 97 %. Če imamo razsmernik učinkovitosti 92 %, to pomeni, da bo naša proizvodnja električne energije 5 % manjša.

IZ TEGA VIDIMO, DA PRI RAZSMERNIKIH NE SMEMO VARČEVATI. Če vam nekdo nudi razsmernik z učinkovitostjo 92 %, na voljo pa je razsmernik drugega proizvajalca enake moči z učinkovitostjo 97 %, vam ga mora ponuditi brezplačno, ker boste v 15 letih zaradi slabše učinkovitosti izgubili točno toliko, kot stane razsmernik učinkovitosti 97 %.  Če vam ga ponudi npr. 60 % ceneje, boste še vedno imeli izgubo.

Commercial Solar Power

Commercial solar power is an up and coming field in the arena of green energy. Any person or company who creates more solar power than they use can connect to the power grid and sell that power so that others may use it.

To encourage the commercialization of solar power, the Solar Power Solutions (SPS) initiative, funded by the U.S. Department of Energy, and other incentives have been put into place to encourage both businesses and residential homes to provide excess solar power to the power grid. These initiatives focus on building photovoltaic infrastructure, financing, education and outreach. Energy service providers, state and local government as well as business and residents are all excited about the prospects of commercial solar power becoming more and more viable.

Because the non-renewable natural resources are becoming more and more scare and therefore more costly, as well as the fact that imported oil can be impacted by many factors, more people want to establish a means of providing power for their need locally. The most practical means of doing so is the implementation of commercial solar power.

In order to provide commercial solar power, it is necessary to connect to the traditional power grid. This is accomplished through uniform interconnection procedures arranged with the energy provider in the area where the commercial solar power is being produced, where from a home or business. This agreement should cover both technical and contractual issues regarding the interconnection. This is very important to protect both the entity providing the commercial solar power and the energy companies. It is also a means of breaking down barriers to the process because all parties will have a firm, legally viable agreement.

Whether small residential solar power producers or 2 Megawatt commercial solar power producers are connected to the grid, the power will save natural resources. It may require updated metering policies in the cases of some energy providers that have not implemented meters that can measure power going both ways on the grid.

During periods of peak usage, the commercial solar power can potentially save the rolling blackouts and brown outs that have caused problems in the past during cold and heat waves. This would not only mean that solar power would be saving the environment but also saving people’s lives. It is not infrequent that during freak weather periods, numerous people, even in the United States die from power failures due to overloads to the power grid.

If we combine all the natural energy sources, such as commercial solar power, home produced solar power, wind generated power and other options, we will not only save money for ourselves, we will have a positive impact on the world as a whole. The effects of traditional energy sources are wreaking havoc on the environment as we know it. Oceans are heating up, the ice cap is melting, weather patterns are changing and much more is occurring on this planet that will potentially make it uninhabitable for our children and their children.