Autonomous photovoltaic systems
Autonomous Photovoltaic Systems: A Sustainable and Cost-Effective Energy Solution
An autonomous photovoltaic (PV) system provides electricity to cottages, boats, or other off-grid locations by harnessing solar energy, eliminating reliance on the HEDNO network. This independence results in no electricity bills, fixed charges, or transmission costs.
Today, autonomous PV systems offer a practical, economical, and reliable solution for electrification. Properly designed and implemented by a qualified engineer, these systems ensure a continuous and adequate power supply to meet any energy demand.
Autonomous PV systems are particularly beneficial in areas where other energy sources are unavailable or impractical. They are designed to meet local energy needs effectively, with total costs varying depending on the system size and energy requirements—from a few hundred to several thousand euros. Maintenance is minimal, consisting primarily of annual tasks such as cleaning the solar panels and inspecting the batteries to ensure optimal performance.
For greater versatility, hybrid systems combine solar and wind energy through the integration of photovoltaic panels, wind turbines, and battery storage. These systems maximize energy generation by utilizing multiple renewable resources simultaneously, providing a robust and sustainable power supply for diverse applications.
With extensive expertise in autonomous photovoltaic systems and a portfolio of hundreds of successful installations across Greece, AENAOS Energy Systems is a trusted provider of reliable and innovative energy solutions. The company offers a comprehensive approach, encompassing meticulous system design, high-quality material supply, and efficient installation services. This integrated process ensures cost-effective and functional results tailored to each client’s unique needs.
Off-grid photovoltaic systems are an excellent solution for powering residential buildings in remote or inaccessible areas that lack connection to the electricity grid. These systems are often a more economical alternative to the high costs of grid extension or traditional energy generation methods, which involve steep operational expenses and prove more costly over time.
By leveraging autonomous photovoltaic systems, homeowners achieve complete energy independence, avoiding reliance on the grid while reducing long-term energy costs. As energy prices continue to rise and power outages sometimes are frequent, off-grid systems offer a stable, reliable, and sustainable energy solution.
The versatility of photovoltaic systems has led to their adoption in a wide range of consumer products, providing efficient and sustainable solutions for numerous applications. Photovoltaics are ideal wherever stand-alone electricity generation is needed for devices with low power consumption. Typical examples include:
- Pocket computers
- Portable electrical devices (e.g., lamps, televisions, refrigerators)
- Caravans and utility trolleys
- Recreational boats and canoes
- Prefabricated houses and cottages
- Camping and outdoor equipment
In the telecommunications sector, photovoltaic systems are indispensable for powering critical infrastructure such as broadcasting transponders, telecommunications networks, remote monitoring and control systems, and weather stations. PV systems are particularly well-suited for installations in remote areas where grid connections are unavailable or impractical.
Photovoltaic systems provide an ideal solution for generating electricity in remote rural areas where grid connections are either impractical or prohibitively expensive. These systems support a wide range of agricultural applications, including:
- Lighting: Providing reliable illumination for farms, outbuildings, and fields.
- Water pumping: Solar-powered systems efficiently pump water for irrigation and general water supply needs.
- Heating: Supporting agricultural processes that require heat, such as greenhouse heating or livestock water systems.
Photovoltaic technology offers a sustainable and energy-efficient solution for outdoor lighting, eliminating the need for a connection to the grid. A typical photovoltaic outdoor lighting system consists of:
- A photovoltaic panel to capture solar energy.
- An accumulator (battery) to store energy.
- A photocell for automatic activation at sunset.
Applications of Photovoltaics in Outdoor Lighting
Photovoltaic-powered outdoor lighting systems are versatile and can be used in a wide range of settings, including:
- Street lighting
- Roads and pathways
- Gardens and parks
- Car parks
- Telephone boxes
- Signaling systems
- Advertising signs
- Safety lighting systems
1. Photovoltaic Panels
Photovoltaic panels are the core component of a solar energy system, converting sunlight into electricity. They act as direct current (DC) power sources and are rated based on their output under optimal conditions (measured in Wp, or watt-peak). Proper orientation and tilt of the panels are crucial factors that significantly impact the system's overall efficiency.
2. Charge Controller
The charge controller ensures the safe and efficient charging of the batteries. Its primary function is to regulate the power output from the photovoltaic panels, adjusting the current and voltage to levels suitable for charging. Additionally, it monitors the battery's charge level, preventing overcharging by halting the process once the battery reaches full capacity. There are two main charge controller technologies i) MPPT (Maximum Power Point Tracking): A more advanced and efficient technology that optimizes energy output from photovoltaic panels and ii) PWM (Pulse Width Modulation): A simpler, older technology with lower efficiency. In modern stand-alone PV systems, MPPT charge controllers are generally preferred due to their superior performance and higher energy efficiency.
3. Battery
The batteries of an autonomous PV system store electricity when energy production is greater than consumption, so that it can be used when solar energy is not available, such as during the night or on cloudy days. The most commonly used batteries in stand-alone PV systems are deep-discharge lead-acid batteries, while in recent years, lithium batteries have been gaining ground due to their higher efficiency and longer lifespan. Photovoltaic batteries are characterized by their voltage (V), their capacity (Ah), and the number of charge-discharge cycles. Batteries are divided into open or closed types and are classified according to their voltage, usually 2V, 6V, and 12V.
The proper functioning of batteries depends to a large extent on the temperature of the environment in which they are located. The ideal temperature is between 20–25°C, as excessively high temperatures can reduce their lifespan, while low temperatures limit their performance. In addition, adequate ventilation is essential, especially for open-type batteries, to avoid gas accumulation. For stand-alone PV systems with high energy demands, the use of 2V cells is recommended, as they offer greater flexibility, durability, and longer lifespans.
4. Inverter
The inverter converts direct current (DC) energy into alternating current (AC). It is characterized by its power rating and is responsible for supplying the necessary power to the loads that an autonomous photovoltaic system can support simultaneously. The inverter is characterized by its power (kVA), the surge power it can provide for short durations, the battery voltage at which it operates, and whether it can charge batteries (simple inverter without charging capability, or hybrid inverter with charging function).
There are two main types of inverters: pure sine wave and modified sine wave. In modern stand-alone PV systems, pure sine wave inverters are preferred because they provide superior power quality, reduce the risk of equipment damage, and improve the overall efficiency of the system.
5. Wind generator
The wind turbine converts wind energy into electricity and is usually used as an auxiliary to photovoltaic systems. It is mainly used in stand-alone photovoltaic systems that require continuous operation in winter, as it can produce energy when sunlight is limited or unavailable, such as on cloudy days or at night.
