Photovoltaics on roofs

Complete guide to installing photovoltaics on roofs


Who has the right to install a small photovoltaic system up to 10kW?

Any individual or small business can participate directly in the program as long as there is a connection to the PPC. That is, the building in which the photovoltaic system will be installed must have a "turtle" connection to the network of the Public Electricity Company. Natural persons, non-traders and natural or legal persons classified as micro enterprises (with up to 10 employees and a turnover of up to 2 million euros) have the right to join the programme. In particular, the owners of the horizontal properties represented by the manager after agreement of the whole, or one of them after the concession of the use of the common area by the others, have the right to join the programme.

What happens in the case of a block of flats where there are many tenants?

A record of a unanimous decision of the general meeting or a written agreement of all co-owners of the building must be made. The same applies to old apartment buildings that do not have a regulation. Also, if a person has the exclusive right to use the roof, he or she may start the installation for his or her own benefit if this is not prohibited by an express provision in the regulations of the block of flats.

Is it necessary to have a solar water heater to add a photovoltaic system?

Yes! The basic requirement for adding a photovoltaic system for the sale of energy is the existence of a solar water heater. The reason is that there should be a unified general understanding among consumers about energy saving issues.

Is there a chance that the PPC will refuse to connect my photovoltaic system?

Yes! For purely technical reasons (such as a saturated electricity network), the PPC has the right to refuse your request for a connection offer.

Is there a requirement to start an escort service?

No. There is no requirement to set up a business or open books. You just need to have a connection to the PPC network and be the owner of the horizontal property.

What are the obligations of the system owner towards the tax authorities?

The small size of the home photovoltaic system ensures that the energy produced corresponds approximately to that consumed by the photovoltaic system's master. Therefore, there are no tax obligations for the operator of the photovoltaic system for the distribution of this energy to the grid. The civilian producer-consumer will have no tax or insurance obligations (opening of books, issuing of invoices, insurance, etc.) whether he is a trader or not.

Will I need a power generation license from the or another government agency as is the case with large photovoltaic systems?

No. There is no requirement for a power generation licence. The RAE is not involved in any way in the whole process. Two contracts will be signed with the PPC. One will be for the connection of the PV system to the public grid and the installation of the new "turtle" meter, while the other will be the contract for the sale of electricity. However, there is an obligation to inform the RAE about the installation of the photovoltaic system.

Is there any other subsidy on the cost of installing photovoltaic panels? Is it in my interest to make the investment without such a subsidy?

No, there is no additional subsidy for the installation costs. However, the high selling price of the produced electricity to the PPC (0,55 EUR/kilowatt hour), ensures a good annual income that guarantees the amortization of the investment within 5-12 years (depending on some parameters such as installation costs, sunshine, loans and others). An average payback period of 7 years can be considered.

For which areas of Greece is the subsidy programme for small photovoltaic installations valid?

The programme covers the whole Greek territory EXCEPT THE AREAS NOT IN THE INTERCONNECTED SYSTEM (i.e. except the non-interconnected islands).

I have a very large terrace (or roof). Can I install more than one photovoltaic system?

No. Only one photovoltaic system may be installed in each building.

What other "papers" do I need apart from those that the PPC will ask me for the connection and the sales contract?

Approval is required for the execution of small-scale works within the meaning of Article 7 par. 1 of Law 3212/2003 (Government Gazette A΄ 308). The conditions of installation will be defined by a circular of the Minister of Environment, Spatial Planning and Public Works. Our approval is provided by the relevant urban planning authority.

Do I need any other additional equipment to connect my PV system to the public electricity grid?

Yes. You will sign a contract with the PPC to install a new "turtle" meter. The meter will essentially be dual and will be able to calculate the energy output from the PV system to the grid and the electricity consumed in the building. The whole process of obtaining the meter will be handled at the local PPC.

I would like to invest in a lot of small photovoltaic systems. Is there any restriction on doing so?

You must be the owner of some horizontal property of the buildings where you wish to install the photovoltaics. If you own (or can be granted) the ownership of several premises you can install a proportional number of photovoltaic systems as long as you are in any case the owner of a horizontal property of the building in which the photovoltaic station is to be installed.

What happens to the VAT I will pay on the purchase and installation of the photovoltaic equipment? Is there any difference if I am a private individual or a "small business"?

If you are a private individual the VAT you will pay will simply be paid and added as an expense to the installation cost. If you are a small business this VAT will obviously be credited to you. Therefore if there is a choice, it is in your interest to install the system as a business as you will offset it with a corresponding amount of VAT that you are likely to collect from your commercial activities. However, in the sale of the energy you produce you will not be able to 'charge' the PPC with additional VAT in either case.
Comment: This choice (or omission) of the ministers clearly unfair to residential users compared to small businesses as the cost of the investment is 19% more expensive for private users.


How much capital (how much money) do I need to spend for a small photovoltaic system on a roof, terrace or roof?

The money needed for a small photovoltaic system depends on the size of the installation you want to make. So for example if someone places 1 photovoltaic panel of 200 watts (including other components) on a roof to sell the electricity it produces to the PPC will need from 700 to 1100 euros. If you install 5 panels of 200 Watts (total 5 x 200 = 1000 Watts or 1 kW (kilowatt)) the corresponding cost will be from 3500 to 5500 euros. The main part of the installation cost is for the photovoltaic panels (or panels or collectors or panels or mirrors or even ...glazing (50% - 70% of the total cost). The rest of the cost is divided between the inverters, the mounting system and secondly the wiring and electrical panels (fuses, switches, lightning protection etc.).
In general, the cost and prices for a fixed photovoltaic system in the Greek market ranges from 3,500 to 5,500 euros per kW or 3.5 to 5.5 euros per watt. Of course the price / Watt ratio decreases the larger the size of the installation.
*The prices we quote do not include VAT.

How much money - income will I get from a small installation in my home or in a block of flats?

The revenue depends on the energy produced (see also question 3) by your photovoltaic system. Near the point where the photovoltaic system is connected to the PPC grid there will be a double meter (the same for the energy we consume) that measures the energy produced by the photovoltaic system in kilowatt hours (kWh). The PPC is obliged to buy this energy by paying 0.55 euro cents per kilowatt hour ( 0.55 euro cents/kWh ).

This means that if we produce, for example, 100 kilowatt hours (100kWh) in a month, the PPC will have to pay us 55 euros.

Therefore, depending on the energy produced by the system, we have the corresponding revenue in euros by multiplying the kilowatt-hours produced by 0.55.

How much energy does a small photovoltaic system produce?

The energy produced by a photovoltaic system has to do with the total power of the photovoltaic panels that our system has (Attention: not the number of panels!!!)

To find the total power of the photovoltaic system we multiply the power of each panel (indicated on a label on the back) and the result is the total installed power of the system. (In rare cases there may be panels of different types in the same system so we do the multiplication twice for the respective panel quantities and finally add up the two subsets).

Example 1: We have 5 photovoltaic panels, each with a power of 180 watts (Watts). The total power of our system will be 5 x 180 = 900 Watts.

Example 2: We have 6 photovoltaic panels with a power of 170 watts each (Watts) and 5 photovoltaic panels with a power of 160 watts each (Watts). The total power for our system will be
a) 6 x 170 = 1020 watts (Watts)
b) 5 x 160 = 800 watts (Watts)
Total 1020 + 800 = 1820 watts (Watts)

The energy produced by our system depends mainly on two factors:

  • The total power of the photovoltaic system (see Step 1 above)
  • The sunshine of the area where we will install the system (solar energy)

The amount of solar energy is different from region to region and in Greece in general it is greater the further south we are. So the greater the amount of solar energy that "falls" on the panels, the more electricity they produce.

In general, in Northern Greece the electricity produced by 1kW (1 kilowatt) of photovoltaic is from 1,150 to 1,250 kWh (kilowatt hours) each year (for a fixed system).

In Central Greece, the electricity produced by 1kW (1 kilowatt) of photovoltaics is from 1,200 to 1,300 kWh (kilowatt hours) each year (for a fixed system).

In Southern Greece, the electricity produced by 1kW (1 kilowatt) of photovoltaics is from 1,250 to 1,400 kWh (kilowatt hours) each year (for a fixed system).

After finding out the total power (from Step 1) of our system and the electricity produced in kilowatts for your area (from Step 2) then multiply the total system power by the electricity production of 1kw for your area and find the total electricity we produce per year (and eventually sell to the PPC).

Example 1: 2 KW photovoltaic system in Drama

  • Total power 2.000 Watt or 2 kW
  • Installation in Drama (1kW produces 1.150kWh)
  • Total production per year 2 x 1.150 = 2.300 kWh
  • Revenue from the sale of energy for the first year 2.300 X 0,55 = 1.265,0 EUR

Example 2: 3.5 KW photovoltaic system in Athens

  • Total power 3.500 Watt or 3,5 kW
  • Installation in Athens (1kW produces 1.340 kWh)
  • Total production per year 3,5 x 1.340 = 4.690 kWh
  • Revenue from the sale of energy for the first year 4.690 X 0,55 = 2.579,5 EUR

Example 3: Photovoltaic system 4,2 KW in Kalamata

  • Total power 4.200 Watt or 4,2 kW
  • Installation in Kalamata (1kW produces 1.240 kWh)
  • Total production per year 4,2 x 1.240 = 5.208 kWh
  • Revenue from the sale of energy for the first year 5.208 X 0,55 = 2.864,4 EUR

For the above examples we assume:

  • Optimal slope of the panels to the south (find the optimal slope in each area click here)
  • Unobstructed panel surface for all day and all days of the year c) Correct choice of materials and correct electrical design and installation

For an automatic revenue calculation you can use selasenergy's free revenue calculation form (click here) (Note: In the "billing method" option select for small system <5kW).

Will the purchase price of a kilowatt hour from the PPC be fixed?

The price (0.55euro/kWh) will be stable until 2012. From 2013 onwards, this price will decrease by 5% per year. However, we should clarify (after contacting the Ministry of Development) that this does not mean that if someone installs a system in 2010 the sales price after 3 years will start to decrease by 5% each year until 2019. The price will be fixed and even increased according to the Consumer Price Index ( follows inflation). So if one connects this year, he will definitely have at least 0.55 and after 5 or 10 years. But if you connect in 2013, the purchase price will be 0.55 x 0.95 = 0.5225 euro per kilowatt hour, while if you connect in 2014 the price will be 0.5225 x 0.95 = 0.4963 euro per kilowatt hour.

What other factors affect the return on the investment I am considering?

Key points that affect the return on investment and that one should pay attention to are the following:

  1. Installation costs
  2. Orientation and inclination of the photovoltaic surface. The panels should "look" to the south and the inclination of the panels in relation to the horizontal plane (if you do not have mobile bases) is for Greece 28 - 32 degrees. See the automatic angle (tilt) calculation here. Regarding the orientation, if your panels are not south (or at least slightly southwest or southeast oriented) we recommend not to install them. The problem of proper orientation is usually more pronounced on roofs while on rooftops it can be solved by proper placement of the PV panel mounts.
  3. Shading! The place of installation should receive the minimum possible shading and this must be taken care of before the panels are installed because afterwards it will be too late. Observe the surface where you are thinking of placing them for a whole winter sunny (if possible) day and choose the spot with the least amount of shading if possible. If there are large buildings that block the sunlight for long periods of time you might have to rethink the whole design of the cladding as well.
  4. Correct selection of photovoltaic panels (output power tolerances, performance guarantees, construction materials, type of photovoltaic cells, tolerances to high temperatures, etc.)
  5. Product warranties for panels and inverters-converters. (Especially for inverters, claim an extended warranty for 20 years).
  6. Correct electrical installation with the special materials and plugs for photovoltaic systems.
  7. Placing the panels in a part of the building where we can be sure of its security against the risk of theft. If we are not sure, we should additionally insure the installation with an insurance company. An alarm system is desirable, as well as the use of anti-theft connection micro-materials during installation.
  8. Washing the panels (and therefore access to water) periodically (once a week or more often) depending on the situation. The deposition of dust, bird droppings etc. can significantly reduce the performance of the system.
How much surface area do I need to install a photovoltaic system on a roof and how much on a tiled roof?

In general, a typical crystalline (monocrystalline or polycrystalline) photovoltaic panel occupies 0.7 - 0.8 square meters for every 100Watt including the aluminium frame. Therefore, we consider that 1kw kilowatt of photovoltaic panels occupies an area of 7.5 square meters/kWp on average.

  1. Epiklini Roof -Keramoskopi: In the case of a sloping roof, the average surface area that can be occupied by a kilowatt of installed photovoltaic panels approaches 8 square meters. On a pitched roof, however, we should place the PV system only on the side "facing" south. It is also advisable that the pitch of the roof is not much less than 28 degrees and not much more than 33 degrees. The optimum roof pitch for all regions of Greece can be found with this tool "find optimum annual PV panel pitch" click here. We should point out at this point that we are referring to the optimal tilt for maximizing efficiency during the year since for each month (or even each day) the optimal tilt is different.
  2. Terrace - flat roof: In the case of the flat surface, the system takes up more space since the ready slope for the photovoltaics offered by a roof should be constructed with special mounting bases for the photovoltaic panels. The result is that each row of photovoltaic panels requires a distance from the previous row to avoid shading of the photovoltaic cells. In this case, a calculation of the shading produced by the arrays should be made and an appropriate distance between the rows of elements should be provided. A general rule of thumb for flat roofs is that roughly 15 square meters per installed kilowatt are needed.

Attention 1! In any case, the indicated required surfaces are indicative and always deviate on a case-by-case basis. You should consult an expert as each location has different characteristics.

Attention 2! The listed surfaces refer to a general standard type of crystalline silicon photovoltaic panels (representing the 80% on the market). For thin film technologies the surfaces are almost twice as large as those mentioned above. More about the types of photovoltaic cells click here.

Important factors that play a role in the above and differentiate the facilities are:

  • Efficiency of PV panels (The higher the efficiency the smaller the required surface area)
  • Type of support system
  • Exact dimensions of the roof (For example, if the side facing south is the largest in a parallelogram space, a much smaller surface may be required)
I don't have the money to implement a photovoltaic installation at the moment. Could I do the installation with a bank loan? Is this worthwhile?

Of course YES. It has been calculated that if someone plans his investment correctly and does the corresponding market research (so as not to pay unnecessary costs) he can put nothing out of his pocket and the photovoltaic system can pay off the loan installments with the income from the energy produced. By a rough calculation: A 12-year loan can be repaid and after 12 years one can have a net profit without actually ever having put a hand in one's pocket.

Example: 3kW installation in Larissa

  • Total cost of installation and connection costs (indicatively EUR 15.000).
  • Take out a loan worth €15,000 with an interest rate of 7.0% and a 12-year repayment period. Total in 12 years we will give the bank €22,213 with an annual instalment of €1,851
  • Estimated energy production per year for 3kW= 3550KWh therefore (for a charge of 0,55euro/KWH)
  • Annual income = €1,952 > annual loan instalment €1,851

This practically means that after 12 years we will have paid off a photovoltaic installation in our house for which we never really spent any money and which has a lifespan of 25 years and therefore we will have profits for 13 more years of FREE ENERGY PRODUCTION WHICH WE CAN CONTINUE TO SAVE AND MAKE MONEY!!!


The installation process step by step.

STEP 1: Informing the interested party to fully understand the project and market research of companies active in photovoltaic systems.
STEP 2: Preparation of an electrical plan, technical study and the relevant application for a connection offer from the local PPC branch. (A licensed engineer or technical company will be needed to sign the plans). The PPC should reply in 20 days.
STEP 3: Approval of small-scale works by the Planning Department of the Prefecture. The conditions will be defined by a circular of the Ministry of Environment and Public Works, which should be issued within 5 days.
STEP 4: If a loan will be used, secure the relevant loan.
STEP 5: Application for a connection contract to the local PPC and implementation of connection works (completion in 20 days). This is essentially the cost of installing the new "turtle" with a double meter for incoming and outgoing electricity (cost 300- 500 euros).
STEP 6: Installation of the photovoltaic system by the company to which you have entrusted the implementation of the construction (duration from 2 to 14 days) for installation costs see B1.
STEP 7: Signing a sales contract with the PPC
STEP 8: Activation of the connection and sale of the produced electricity to the PPC.

You are now a small electricity producer! Good profits!