What are the off grid/standalone/backup energy systems with photovoltaics/solar pv panels and batteries?

The off grid photovoltaic/solar panel systems are independent power generation plants operating without the need of the electrical distribution grid. These standalone  systems are able to supply the standard electrical appliances and machines of the market with enough power at nominal voltage of 230V/50Hz or different if required. Their basic principle is the transformation of solar energy/radiation into electricity for powering the consumption loads and for excess/surplus energy storage during the day. This energy is stored in the battery pack of the system and consumed mainly during the night or a cloudy day. An off grid photovoltaic/solar panel pv system may also be extended with an electric generator for extra safety during the winter when solar energy is less than needed due to weather conditions (cloudy days). Before choosing an off grid solar pv system, it is important for us to conduct a detailed  and analytical energy study in order to help the self cosumer select the appropriate materials of best quality with long-term benefits. This approach guarantees that the final system will meet the expectations for energy  consumption and storage which may vary from day to day due to different energy use profiles.

What are the main parts of an off grid/backup/standalone solar power photovoltaic (pv) system?

The main parts of an autonomous photovoltaic solar pv power generation plant are the following:

• The power generation unit, which consists of one or more arrays of photovoltaic (pv) solar panels. The type and the number of panels depends on the energy consumption profile of the user, the electrical loads, etc.
• The energy storage unit with batteries, which absorbs part of the excess/surplus energy produced to charge them at full capacity. The energy stored is used during the night or cloudy days. Choosing the appropriate type and capacity of the battery is very important for the normal operation of the entire system 24/7 for up to 365 days.
• The charge regulator which converts the direct voltage (DC) output of the photovoltaic solar panels into an appropriate voltage for charging each different type of battery. The high quality of the charge regulator guarantees the optimal charging of the battery according to the manufacturer’s specifications for long-term operation.
• The off grid inverter is the device that transforms direct current (DC) into alternating current (AC), compatible with all electrical and electronic devices (230V/50Hz). The inverters for stand-alone/off grid systems may have additional features according to the self consumer’s needs and are selected accordingly.
• The switching protective devices for the user’s and the whole system’s safety

Who may install photovoltaic/solar panel autonomous power systems with off grid/standalone/backup functionality using batteries for complete energy independence without the electric utility grid?

All the individuals, freelancers, businesses/companies and legal persons of public and private law, who either own the space/area at which the photovoltaic/solar system will be installed, or have the legal use of it with the owner’s written approval (e.g. renting or free concession contract).

Where can the solar off grid systems be installed for standalone/backup operation?

Photovoltaic/solar off grid pv systems can be installed on roofs (tiled or flat), shelters, facades, pergolas, sunshades, parking areas, warehouses, but also on the ground as long as the urban planning and environmental legislation is not violated.

In which cases are the off grid solar pv systems recommended for standalone operation?

Energy backup power systems with off-grid functionality are proposed for the following indicative cases:

• For main/permanent residences depending on the energy consumption profile. Especially modern high energy efficient homes can rely on standalone systems for partial or complete energy independence from the electricity grid.
• For small businesses/companies, shops, offices, etc.
• For trailers, caravans, mobile food vehicles (solar canteens), camping vehicles (pv solar camper vans), for conventional cars with custom made solar panel expansions (custom solar camper vans) and for containers.
• For holiday homes, cottages for seasonal/occasional residence, for winter or summer accommodation.
• Remote installations that need electricity (e.g. telecommunication huts, electronic equipment, etc).

What are the advantages of pv solar energy autonomous systems operating off the utility/distribution grid as standalone systems?

• The owner of an off grid solar power system does not receive any electricity bills, so the payback time of the initial investment is minimized to 6-8 years approximetely.
• No license, approval or permission is needed from any authorities in Greece as long as general building regulations are met during installation.
• The initial system can be expanded with more photovoltaic/solar panels and more batteries in the future, provided that it is designed according to certain specifications.
• It is possible to supply electric power to facilities that are far away from the power distribution grid.
• Electrical appliances and electronic equipment are fully protected because of the better voltage and current output from the inverter.
• Immunity to voltage fluctuations due to lightning strikes at the electric utility grid which reduce the lifetime of the connected devices.
• Τransmission and distribution power losses are significantly reduced compared to the facilities that are conventionally connected to the grid. This leads to increased energy efficiency, reduced air and water pollution and less metal mining needed for the cable extension of the national electric grid.
• The energy is produced far away from big power plants (decentralized and distributed power generation).
• The environment is protected and the economy is supported by the exploitation of clean, renewable/sustainable solar energy which is consumed or stored on site.
• All materials are recyclable.
• Reduced maintenance needs for the operation of the whole system.
• Remote monitoring and supervision of the important parameters of the solar panel pv system through internet telemetry.