Category: Solar Energy

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Solar panels and how they work

“What is a Solar Panel?”


 solar panel also known as “PV panel” is a device that converts light from the sun, which is composed of particles of energy called “photons”, into electricity that can be used to power electrical loads.

Solar panels can be used for a wide variety of applications including , telecommunications equipment, Water Pumps for irrigation or household use and of course for the production of electricity by residential and commercial solar electric systems.


We will discuss the history, technology, and benefits of solar panels. We will learn how solar panels work, how they are made, how they create electricity,

History of Solar Panel


The history of solar panels can be traced back to the 19th century when the photovoltaic effect was first discovered by French physicist Alexandre-Edmond Becquerel in 1839. The photovoltaic effect refers to the process by which certain materials can generate an electrical current when exposed to sunlight


However, it was not until the mid-20th century that the first practical solar cells were developed. In 1954, Bell Labs produced the first silicon solar cell, which was capable of converting sunlight into electricity with an efficiency of 6 percent. This breakthrough led to the development of the first solar panels for use in space exploration.


During the 1960s and 1970s, advances in solar cell technology led to the development of larger, more efficient solar panels for use on Earth. These early solar panels were expensive and primarily used for remote power applications, such as powering satellites and lighthouses.


In the 1980s, the price of solar panels began to decline due to advancements in manufacturing processes and increased demand for renewable energy sources. This led to the widespread adoption of solar panels for residential and commercial use.


Today, solar panels are used in a variety of applications, from powering homes and businesses to providing electricity to remote areas without access to a traditional power grid. Advances in solar cell technology have also led to the development of more efficient and cost-effective solar panels, making solar energy an increasingly viable option for meeting our energy needs.

Solar Panel Types


There are three main types of solar panels:


These are made from a single crystal of silicon and are the most efficient type of solar panel available. They have a higher power output and take up less space than other types of solar panels.


These are made from a thin layer of photovoltaic material (such as amorphous silicon, cadmium telluride, or copper indium gallium selenide) and are the least efficient type of solar panel. However, they are also the least expensive and can be a good option for large-scale installations where cost is a major factor. Thin-film solar panels are also more flexible than other types of solar panels and can be used in a wider range of applications


These are made from multiple crystals of silicon and are less efficient than monocrystalline solar panels. However, they are also less expensive and can be a good option for those on a budget.

How does a solar panel work?

Solar panels collect clean renewable energy in the form of sunlight and convert that light into electricity which can then be used to provide power for electrical loads.

They are comprised of several individual solar cells which are themselves composed of layers of silicon, phosphorous (which provides the negative charge), and boron (which provides the positive charge). They absorb the photons and in doing so initiate an electric current. The resulting energy generated from photons striking the surface of the solar panel allows electrons to be knocked out of their atomic orbits and released into the electric field generated by the solar cells which then pull these free electrons into a directional current. This entire process is known as the Photovoltaic Effect. An average home has more than enough roof area for the necessary number of solar panels for producing enough solar energy to supply all of its power.

Benefits of using solar panels

Renewable and sustainable:

Solar energy is a renewable resource, which means that it is virtually limitless and will never run out. It is also sustainable, as it does not emit harmful pollutants or contribute to climate change.


By generating your own electricity with solar panels, you can become less reliant on traditional energy sources and reduce your carbon footprint.


While the initial cost of installing solar panels can be expensive, the long-term savings can be significant. Solar energy can greatly reduce or even eliminate your electricity bills, and the cost of solar panels has been decreasing in recent years

Low maintenance:

Solar panels require very little maintenance, as they have no moving parts and are designed to last for many years.

Frequent cleaning is recommended to increase efficiency from the dust that block the suns arrays from reaching the solar panels.


Solar energy can be used in a wide variety of applications, from powering homes and businesses to providing electricity to remote locations and powering satellites in space

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Solar Water Heaters

“What is a Solar Water Heater?”


 solar water heater is a type of renewable energy technology that uses the energy from the sun to heat water for domestic or industrial use. The system typically consists of a solar collector, which is usually mounted on the roof or a nearby structure to capture sunlight and convert it into heat, and a storage tank to store the heated water.

The heated water is then stored in an insulated tank, where it can be used for a variety of purposes such as bathing, washing, or space heating. Solar water heaters can be used in both residential and commercial applications, and they can help to reduce energy costs and greenhouse gas emissions associated with traditional fossil fuel-based water heating systems.


The solar collector can either be a flat-plate collector, which uses a flat panel to absorb sunlight and transfer the heat to the water, or an evacuated tube collector, which uses a series of vacuum-sealed tubes to trap sunlight and heat the water.

There are several types of solar water heaters, and the main differences between them lie in the way they collect and store solar energy. Here are a few examples:

Flat Plate Solar Water Heater:

This is the most common type of solar water heater, which consists of a flat absorber plate made of copper or aluminum that is painted or coated with a selective coating to absorb the maximum amount of solar energy. The plate is placed inside a flat, insulated box with a transparent cover, which allows sunlight to enter and heat the plate. The water is circulated through the pipes that are connected to the plate, and the heat is transferred from the plate to the water.


Evacuated Tube Solar Water Heater:

This type of solar water heater uses a series of evacuated glass tubes that are connected to a manifold, which is located above the tank. Each tube contains a heat pipe that transfers the heat to the manifold, where it is collected and transferred to the water tank. The evacuated tubes are more efficient than flat plate collectors in colder climates because they are better at retaining heat.

I ntegral Collector-Storage Solar Water Heater:

 This type of solar water heater combines the collector and storage tank in a single unit, which reduces the amount of plumbing required. The collector is usually a metal or plastic box with a glazed top, which traps the solar radiation and heats the water inside the tank.


Thermosiphon Solar Water Heater:

This type of solar water heater uses natural convection to circulate water between the collector and the storage tank. The collector is mounted on the roof, and the storage tank is located below it. The water in the collector heats up and rises to the tank, while the cooler water in the tank flows down to the collector.

Solar water heaters come in various types and designs, but the most common ones are flat-plate collectors and evacuated tube collectors. The main differences between these two types are:

E fficiency:

Evacuated tube collectors are generally more efficient than flat-plate collectors because they can maintain high temperatures even in colder climates. This means they can produce hot water even on cloudy or overcast days.

C ost:

Evacuated tube collectors tend to be more expensive than flat-plate collectors because of their higher efficiency and more complex design.

F ragility:

Flat-plate collectors are generally less fragile than evacuated tube collectors because they have a simpler design with fewer parts that can break or wear out.

M aintenance:

Both types of solar water heaters require regular maintenance, but evacuated tube collectors are generally easier to maintain because their individual tubes can be replaced if damaged, while flat-plate collectors require more extensive repairs if the panel itself is damaged.

Overall, the choice between flat-plate and evacuated tube solar water heaters will depend on your specific needs, climate, and budget. It’s best to consult with a professional installer to determine which type of solar water heater is best for your situation.

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Sizing considerations for a solar system

Designing a solar home system can be a challenging task, and even small mistakes can lead to significant issues down the road. Here are some tips on how to avoid mistakes when designing a solar home system:


Poor System Design (Under-estimating/Over-estimating energy needs)

A poorly designed solar home system can lead to performance issues and lower efficiency. Ensure that the system design is well thought out and includes all necessary components, including solar panels, inverters, batteries, and charge controllers. The design should also consider the system’s capacity, expected lifespan, and maintenance requirements.

One common mistake is to overestimate energy needs, leading to a system that is more expensive than necessary. Before designing the solar home system, calculate the average daily energy consumption to determine the appropriate size of the system. This can be done by reviewing energy bills, using an energy consumption calculator, or consulting with a solar professional.



Poor Panel Orientation

In the northern hemisphere, solar panels should ideally be installed face south, while in the southern hemisphere, they should face north. This is because the sun appears to move across the sky from east to west, so solar panels facing south (in the northern hemisphere) or north (in the southern hemisphere) will receive the most direct sunlight over the course of the day.


However, there may be other factors to consider as well, such as the angle of the roof and shading from nearby buildings or trees. A qualified solar installer can help you determine the best orientation for your specific situation and maximize the energy production of your solar panels.


Considering Autonomy Days

Solar home systems are designed to operate in a wide range of weather conditions, but extreme weather conditions can affect the system’s performance. When designing the system, consider the local climate and weather patterns and ensure the system is designed to withstand extreme weather conditions such as high winds, heavy snowfall, or hailstorms.

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Growth of solar energy in Kenya and its potential

It is almost a century since the modern solar cell was invented. Solar technology has been evolving since and it is now one of the most affordable and reliable sources of renewable energy in many rural parts of the developing world.

With the advent of the 21st century came the increased uptake of solar energy in Kenya. This coincided with the increased penetration of Mobile phones and surge in the number of middle-income Kenyans. Access to electricity became a necessity where each household required at least a charging point for their phones. Therefore, Solar became the main power option for many households and small businesses that were not connected to the grid. Today, Kenya has one of the highest solar power connections per capita in the developing world, just second to India.

Solar for productive use has also evolved over the years. Solar is now applied across a spectrum of applications ranging from water pumping, lighting, heating, ventilation and irrigation. The applications range from mega plants, with the largest plant in the world currently located in India with a capacity of 2,700 MW, to small PICO solar systems that use small light weight photovoltaic panels to generate power in a wide range of small and portable applications such as lanterns, shavers, incubators, amplifies etc.

 Despite the government efforts in rural electrification, almost 17 million Kenyans do not have access to any form of electricity. In addition, those with access are looking for other alternative sources of power due to the high cost and unreliability of the supply from Kenya power, the only power utility company in Kenya. Many have installed solar either as back up (to have power during power cuts) or to reduce their power costs. Particularly, industrial and huge commercial enterprises such as manufacturing companies, petrol stations and malls have embraced solar energy to reduce their power bills with some like Kenya Breweries opting to go completely off-grid in the next few years.

The government of Kenya has played some role, though ambivalent sometimes, in the growth of solar energy in Kenya. The government decision to remove duty and exempt VAT on solar equipment such as panels, batteries and controllers has played a major role in making solar power affordable to many Kenyans. Although the solar market in Kenya is largely driven by the private sector, the government has in the recent past embarked on large solar power plants that feed to the national grid. The Garissa solar power station with 55MW capacity is the largest grid-connected solar plant in East and Central Africa.

However, challenges still abound the solar sector which has limited the realization of its full potential. Some of the major challenges include;


Lack of access to finance- The initial cost of purchasing solar is still fairly high and many customers lack the finances to pay for the system upfront. The options available for financing solar are minimal with banks and other financial institutions shying away from coming up with products that target the solar market. To bridge the gap some solar companies are now offering PAYGO (Pay As You Go) financing model whereby a customer pays some deposit and the balance in installments over a period of time.


Lack of awareness- There is general lack of awareness, especially in rural areas, about the available solar options and their benefits. Increasing awareness will enable people to understand and make informed decisions. Currently, many people rely on user experience from people they interact with and if that experience is not good due to factors such as quality of equipment used or workmanship, the perception about solar may be distorted.


Skilled labor- There are no many experts in the solar sector. The Energy regulation requires only licensed technicians to design and install solar but most technicians are self-trained and operate without a license. This affects the quality of solutions that are offered to customers hence diminishing customer experience in using solar.

“Despite the aforementioned challenges, Solar energy will continue to play crucial role in providing clean energy to existing and future generations in Kenya.”