Autonomous PV systems are the ideal choice for those looking for absolute energy independence. It is the optimal and often the only solution in cases without interconnection with the electrical network.

They have several other advantages such as:

• They work stably protecting the devices from interruptions and overvoltages.
• They do not pollute the environment with pollutants. With only a 3kWp system we will avoid the appeal of 1 ton of CO2 in 20 years.
• They operate completely silently.
• They require minimal maintenance
• They have high efficiency with very short paybacks.
• Help wean the planet off hydrocarbons.
• They have great adaptability, reliability, and lifetime.
• Energy costs are not affected by oil prices and are stable.
• They act as chargers for electric transport systems such as bicycles, scooters, and cars.

How does it work?

In an autonomous system the photovoltaic panels collect some of the incident solar radiation through the cells and convert it into direct current (DC). Then, through the intelligent MPPT charge controller, this current is directed partly to the inverter, which converts the direct current (DC) into alternating current (AC). When there is no sunshine,

the user takes back the stored energy from the batteries up to a discharge limit (C) e.g., 60% to preserve battery life. The autonomy depends to the greatest extent on the capacity of the batteries which is measured in (Ah) and multiplied by the voltage (V) gives us the amount of stored energy in (Wh).

System selection

For the selection of the system, the energy needs (device loads), their mode of operation (simultaneous or sequential) as well as the operating time in combination with the winter-summer load distribution are analyzed. Also, the space where the panels will be placed, and the type of system (simple or hybrid) are considered.

Cost

The price of an autonomous photovoltaic system is proportional to the requirements. The cost to the greatest extent concerns the construction materials and mainly the batteries. A good system with quality name brand materials will last longer so pay for itself faster, have official dealer/manufacturer warranties and perform safely without problems for its lifetime.

PV deployment on agricultural land has been around since the beginning of utility PV, but in some cases, crops have been replaced by PV and thus land use has shifted primarily from agriculture to electricity generation. With higher PV penetration rates, competition for land may limit PV deployment in some countries. Dual land use is an option that is being thoroughly explored around the world to address this issue.

The potential of PV on agricultural land and how it can help meet RES targets has been highlighted in some areas and both interest and reluctance have increased. On the one hand, the potential of the rural PV market is unparalleled. An example of the potential relative importance of this sector, in Japan a mapping of all agricultural land suitable for PV concluded that just 10% could cover 440 GW, with 6.5 GW installed in 2021 for all sectors reaching 78.2 GW cumulative installed capacity. South Korea's rural PV development outlook is 10 GW in 2030, half of the cumulative installed capacity at the end of 2021 (21.5 GW). In France, between 5 and 10 GW could be installed using 0.1% of agricultural land (agricultural land covers half of the French territory), while annual installations reached 3.4 GW in 2021. The potential of 1% of the European Union's agricultural land was estimated at 410 GW, with 29.3 GW installed in the European Union in 2021.

In most countries rural PV or PV on agricultural land is divided into sectors:

• PV systems above crops or plants. The system allows different types of crops to be grown with reduced solar radiation, allowing better growth in sunny areas and potentially new business models, such as recovering damaged crops for example or growing different crops that would not be profitable in certain areas. This dual use necessitates a different kind of photovoltaic systems, which can in some cases change their position, from horizontal to vertical and designed either to maximize solar production or to maximize crop production depending on weather conditions. Monitoring systems are not the only element that can contribute to the maintenance or enhancement of agricultural production, which is a requirement to qualify as agro-PV. The profitability of agricultural production must dominate, and energy production is an added value.
• Crops, pastures, livestock between PV. The systems must allow the land to maintain its agricultural purpose. The space between rows or heights are adjustable. These systems are cost effective. Energy production dominates, but agricultural production must be maintained.

PV technology can be used to power an installation in the agricultural sector (e.g., pumping stations) in the Greece-Albania cross-border area, because:

• Energy produced using photovoltaics and water consumption could be balanced more easily than using other RES.
• PV systems use fewer technological processes to transform solar energy into electricity.
• PV systems can be located next to or within the facilities of each public sector.
• PV power can be hybridized with other non-renewable energy sources by connecting the installation to the grid or to a diesel generator to ensure energy sufficiency under all conditions.

A critical element of the design is to determine the required power of the PV power system, Pel,PV (W). Critical data required for this design are the volume of the reservoirs of the water management facility Vop (m3) and total power PPS (W) of the main pumping station (MPS).

Each service of the public and wider public sector will be able to use the PV system that works together with the reservoirs in order to provide a continuous supply of water.

"PV System-Pump Station-Storage Tank"

The Household Sector is a big and multifaceted challenge in terms of trying to save Energy, as it is difficult to use restrictive measures regarding Energy consumption for heating / cooling, lighting, or other domestic uses. Therefore, it is strongly recommended by all operators to install residential PV systems on the roofs or roofs of buildings to create a satisfactory total installed capacity in the cross-border area that will contribute substantially to the green transition and sustainability.

In Greece, for building permits submitted from 1.1.2023 specifically for residential buildings, the minimum power of photovoltaic systems amounts to 2 kWp for buildings with 2 apartments, 3 kWp for buildings with 3-5 apartments and 6 kWp for buildings with 6 and now apartments. In case of installation and storage system of the produced electricity, the minimum capacity of these systems amounts to 6 kWh for residential buildings with up to 2 apartments, 12 kWh for buildings with 3-5 apartments and 18 kWh for buildings with 6 or more apartments.

The "photovoltaic on the roof" scheme whereby a photovoltaic is installed and all electricity is sold to the Public Electricity Company at a fixed price of 8.7 cents/kWh for 20 years is in place. The program envisages the installation of Photovoltaic Systems with a power of up to 6 kWp on roofs, roofs of buildings, terraces, canopies, and adjacent plots. This solution is superior to netmetering energy compensation in the case of buildings with small and sporadic consumption, such as e.g., the cottages.

How does it work?

The Photovoltaic up to 6kWp is installed on the roof or terrace of our house and all the energy it produces injects it into the public grid. A meter is installed which measures our production in kWh and in each settlement bill PPC deducts our consumption and credits us with any difference.

System Selection

Before installing the equipment, it is necessary to study, design and calculate, down to the last detail, all the systems and materials that make up an interconnected Photovoltaic (inverter inverter, support bases, connections, panels, cable cross-sections, etc.).

Cost

The price of a 3-6kWp home power generation system can range from 4,000-8,000 euros, depending on the case.

Regarding the Tertiary Sector, compared to the household, the following are highlighted:

• Consumptions are higher than in the domestic sector and therefore the optimal PV power will be higher and the cost per kW lower.
• The cost of supply and installation of PV is lower than in the residential sector due to the VAT.
• The electricity billing tariff is higher than that of the domestic consumer.
• The total energy produced (for system power up to 10 kW) will be able to be self-consumed thus maximizing the financial benefit due to not charging regulated network charges (for energy).

Consequently, better results are obtained in terms of payback time and IRR, and it is indicated that for a 10 kW PV system and for the charges of scenario 1, an IRR of 13.9% and a payback period of 7.2 years is obtained.

Especially for businesses, the low limit for allowable system sizes covers very small businesses that, in the vast majority, do not have available space to install PV and small A/C. For the largest consumptions, the maximum amount of energy of 15,000 kWh corresponds to a very small percentage of the total consumption to create a sufficient incentive for making the investment.