The sun is a source of energy, a massive source at that. Solar power is the energy that is generated from sunlight through a process known as the photo-voltaic effect, generally known as PV. The energy from the sun’s rays is converted into electricity that can power equipment at home or in the office – TV, fridge, lights, machines and other equipment.
In order to generate solar energy for a building, a solar power system is needed. The system is comprised of different components that work together to produce electricity.
Components of a solar system in Kenya will include the following:
Solar panels capture the energy from the sun. Solar panels vary in physical size, electrical output power -in watts- and efficiency. The panels can be mounted on a building’s roof or can be installed on aground-mount structure. Solar panels come in different sizes, both physical sizes and power ratings, ranging from small systems of 10 watts to bigger panels of upto 600 watts. The choice of which solar panels to use is dependent on the power requirement.
Inverters convert the energy captured from the sun (known as direct current, DC), to a usable form of power that can power appliances, known as alternating current AC. There are several types of inverters: off-grid inverters are used where there is no electricity completely. They are usually used together with batteries. Grid-tied inverters are applied when connecting solar where main electricity is available, and they work with supply from the utility company. Usually these systems have no batteries. Hybrid inverters combine the capabilities of both off-grid and grid-tie inverters, and are becoming more popular in common small scale application.
Mounting & Racking
Solar panels are mounted either on the roof or on the ground using steel or alluminium structures. Roof installations are more common and generally cheaper, because they utilize an already existing resource to provide space for the installations. It is important to ensure structures mounted on the roof is properly sealed so as to protect the roof against the elements and leakages. Ground mount solar systems are usually used in cases where there is limited roof space. The systems tend to be costly because of the accompanying civil works that need to be done.
Batteries are used for storing the energy generated by the solar panels during the day when the sun is out, so that the power can be utilized when the sun is out. There are different types, technologies and sizes of batteries which can be used for a solar system. The most common solar batteries in the market have been Lead-acid batteries, which are affordable and readily available in the market. There drawbacks are that they are bulky and heavy, and therefore not ideal for places with limited available space. Also, due to their composition, there capacity to keep power is limited and therefore more are required. Lithium batteries are increasingly becoming the choice battery type the market. Its advantages include the fact that they charge first, are light weight compared to lead-acid batteries, and have a huge capacity for storing power. They are generally more pricey than lead acid batteries.
For systems with batteries, charge controllers are used to control the charging and discharging of the battery in order to ensure optimum system performance. Some inverters come with integrated controllers and are referred to as Inverter-Chargers. Charge controllers have different current ratings, and the choice of the controller is determined by the system design.
These are the core components of a typical solar system installed in Kenya. Other components of the solar system include wiring, fuses, and disconnects. Also, depending on the requirement of the installation, monitoring devices can be added to the system. This assist in troubleshooting issues such as defective equipment as well as monitoring output remotely.
Over time the products and solutions have improved, both in terms of efficiencies as well as features, options and packages. All-in-one power backups are becoming common in the market. With the exception of the solar panels, all-in-one backups offer all the above components in a box. This has the advantage of small physical footprint, scalability and ease of installation and support. The SolarBOX by Inborn Energy is one such product that comes in sizes of3, 6 and 10kwH and is ideal for powering homes on solar.