Solar PV Systems: Applications, Grid Integration, and Radiation

Solar Photovoltaic Applications: Powering Our World

Solar photovoltaic (PV) devices can supply a wide range of electrical appliances. These applications are broadly classified into two main groups:

1. Isolated Network Applications (Off-Grid PV)

These are stand-alone installations where electricity generation is used for self-consumption. Within this category, you can find:

• Space Applications: Powering satellites and spacecraft.
• Rural Electrification: Individual systems providing power to remote areas.
• Lighting: Stand-alone solar lighting solutions for various environments.
• Photovoltaic Water Pumping: This is one of the major applications of photovoltaics. Its main advantage is that it often does not require batteries, as solar energy is directly transformed into water potential (e.g., by pumping water to a high storage tank). These systems are highly reliable, leading to widespread deployment (several thousand worldwide). The power generator typically ranges between 1 and 10 kWp, with an application range between 500 and 4,000 m³/day.
• Telephony and Telecommunications: Providing power for remote communication infrastructure.
• Cathodic Protection Systems: Protecting pipelines and other metallic structures from corrosion.

2. Grid-Connected Photovoltaic Applications

In these systems, electricity is generated during daylight hours and injected into the main electrical grid.

Building-Integrated Photovoltaics (BIPV)

The modular nature of PV technology makes it possible to adapt panels to different support structures, including the building itself. This means the building's design can significantly influence the layout of the PV installation. This type of installation is particularly important in countries like Germany and Japan, with the latter being home to one of the largest building-integrated installations at the Sharp factory, boasting 5.21 MWp installed.

A key advantage of these facilities is that they utilize space that would otherwise have no other use, even in densely populated areas. This possibility is unique to photovoltaics, as other renewable energy sources typically require open space for installation. If the PV system is projected alongside the rest of the building, it can be fully integrated, potentially serving other roles such as lighting for an indoor patio or as awnings.

Other Grid-Connected Applications

Examples include parking facilities, or as sound barriers along highways and railroad tracks.

Understanding Global Solar Radiation and Its Components

Solar radiation reaching the outer atmosphere, known as extra-atmospheric radiation, is initially uniform. However, as it passes through the atmosphere, it interacts with atmospheric components, undergoing phenomena such as reflection, scattering, and absorption.

Consequently, the radiation reaching the Earth's surface has reduced power. During this atmospheric journey, a diffuse component is added, originating from the entire celestial sphere.

A photovoltaic generator captures not only these two components (direct and diffuse) but also the radiation reflected from the ground, known as albedo radiation.

The sum of these three components — direct (B), diffuse (D), and albedo (R) — constitutes global solar radiation.

Specialized instruments called pyranometers are used to measure global solar radiation.