Fossil fuels and hydroelectric are the biggest sources of electricity in Africa.

Oil and gas dominate power generation in North and West Africa; Hydroelectric and some geothermal dominate in East and Central Africa; and coal and some hydroelectric dominate in Southern Africa.

Yet, according to the November 2019 International Energy Agency (IEA) report, Africa Energy Outlook 2019, 600 million Africans, which is over half of Africa’s population, still lack access to electricity.

Therefore, for whatever reason, fossil-fuel and hydroelectric power generation alone have not been able to fully power Africa.

And they probably cannot do so in the future.

Fossil fuels are environmentally-unfriendly, finite resources that one day will run out, while global warming-induced droughts will increasingly threaten hydroelectric resources.

Given that Africa, on average, gets the most sunshine out of all the seven continents, solar power must play a part in the electrification of the continent, especially if Africa is to meet United Nations Sustainable Development Goal 7 beyond 2030.

Tanzania is now looking to reduce dependency on hydroelectricity with significant solar power in the long-term. 

Why is the government reducing dependency on hydroelectricity?

THE HYDROELECTRIC RISK

As global warming climate change intensifies, droughts have become more prolonged and severe. 

These droughts regularly push water levels in dams to dangerously low levels as rivers shrink, often forcing TANESCO to shut down hydroelectric plants and plunge the country into devastating blackouts.

In 2013, to break this vicious cycle of droughts and electricity blackouts, the government embarked on a 10-year initiative to diversify the country’s source of electricity away from hydroelectric. 

According to the Ministry of Energy, the government aims to increase power generation capacity from the current 1,600 megawatts (MW) to 10,000 MW by 2025 through investment in thermal and renewable energy.

The government seems committed to this investment strategy, as natural gas now accounts for more than half of all power generation, according to the latest outlook from the IEA.

But the country potentially has more solar resources than natural gas, so if properly harnessed solar power could account for more power generation than even natural gas.

CURRENT STATE OF SOLAR POWER GENERATION

Privately-owned independent power producers (IPPs) compete with TANESCO primarily in fossil-fuelled power generation fed into the national grid.

Natural gas now accounts for over half of the country’s grid-connected (or “on-grid”) power generation, followed by hydropower, and then oil, which is mostly used for peak demand back-up.

Currently, neither TANESCO nor IPPs generate any solar power fed into the national grid.

Things are different in the rural areas and other parts of the country not connected to the national grid.

In these “off-grid” areas, solar power is becoming very popular because of small power producers (SPPs).

These privately-owned SPPs, in partnerships with the Rural Energy Agency (REA) and TANESCO, supply solar electricity to villages through mostly isolated mini-grids.

Or, they independently install stand-alone solar photovoltaic (PV) systems that generate electricity for individual households and businesses. 

SPPs and solar mini-grids are pushing solar power in Tanzania to unprecedented heights.

HOW DOES SOLAR POWER WORK EXACTLY?

The way you consume solar power is to install a solar photovoltaic (PV) system on your premises. A solar PV system is a technology that converts sunlight into usable electricity.

The key components of a solar system are: Solar panels, batteries, a charge controller for a stand-alone system, an inverter for a grid-connected system, and a mounting structure.

The table below summarizes what each component does to make your system work.

TABLE 1. COMPONENTS OF A SOLAR INSTALLATION

Obviously, you need wires/cables to connect these components.

WHAT DETERMINES THE PERFORMANCE OF YOUR SOLAR INSTALLATION? 

Assuming you’ve engaged a competent solar installer to properly set-up your solar system, then the main determinants of its performance are: Solar panel efficiency, Inverter efficiency, Solar battery capability, and General system maintenance.

Solar Panel Efficiency

Since your solar panel is the most important component of your system, you can say your solar panel efficiency is the overall most important determinant of your system’s performance.

So, when picking a panel for your system, you should go for the highest efficiency panel you can get at the price you can afford.

The efficiency of a solar panel is its ability to convert sunlight energy into electricity. 

Solar panel manufacturers always state the efficiency ratings for their products in percentages so you can check the rating before you buy a panel.

The higher the efficiency rating of a panel the better its ability to convert sunlight into electricity. 

Now, the factors that influence a panel’s efficiency are as follows:

1. Cell Type 

A solar panel is a group of solar cells joined together. 

There are three major types of solar cells: Monocrystalline, Polycrystalline (or Multi-Crystalline), and Thin-film (or Amorphous). 

Monocrystalline solar panels typically have the highest efficiencies and tend to generate more power than other types of panels.

Because of their high efficiencies, monocrystalline panels are best for situations where there’s limited space on the ground or on the roof to place the solar panels.

Polycrystalline panels have lower efficiencies than monocrystalline ones but if you have plenty of ground or rooftop space to place your panels, then you should consider them.

Thin-film solar panels have the lowest efficiencies but because of their light weight, they are used for roofs that cannot handle the other two, heavier types.

2. Placement

While most people place their solar arrays on roofs, you should consider placing them on the ground instead if you have a lot of ground space.

A ground-mounted array (see above) is easier to access when you want to clean it, and it’s easier to tilt the array to the angle that will maximize the amount of sunlight it gets.

Furthermore, there’s better cooling air circulation around a ground mounted array. 

3. Orientation

Since Tanzania lies just south of the equator, your solar array should face north to catch most of the peak afternoon sun and thus to increase efficiency. 

4. Shade

Shading from a building or a tree will reduce the efficiency of your array, whether the panels are ground-mounted or rooftop mounted.

5. Temperature

Solar panels need sunlight to work. But too much heat from sunlight can decrease your array’s efficiency.

You can minimize the heat around your array by mounting the panels on the ground to maximize airflow around them.

If you must mount the array on the roof because of lack of ground space, then you should elevate the panels a few inches above your roof to allow some airflow underneath them.

6. Degradation

Your solar array’s efficiency will decrease naturally over time from normal wear and tear. 

This natural decrease called degradation will happen even if everything else about your solar panels or your solar system as a whole were perfect.

The rate at which this degradation happens over time is called the degradation rate, and high-end panels like monocrystalline types tend to have lower degradation rates than cheaper counterparts.

Inverter Efficiency

Inverters are probably the most complex component of your solar installation because of what they do.

An inverter efficiency measures how much of the DC current from your solar array an inverter converts to AC. Therefore, it pays to use a highly-efficient inverter that will convert as much as possible of the DC.

However, no inverter is 100 percent efficient, so there will be some losses in the conversion process.

The key thing is to use the highest efficiency inverter that will match the electricity output from your solar array.

Like solar panels, inverters come in different types and sizes. 

Read more about design of solar systems

Storage Battery Capability

A solar battery is a technology that stores electricity produced by your solar array.

Whether or not your solar system is connected to a grid, you may need a battery as back-up system.

Why?

Well, if you’re connected to the grid, then the grid is your system’s back-up.

But what happens when a power outage, a scheduled maintenance, or a natural disaster takes down the grid?

A battery will store electricity you can use during power supply interruptions.

Then, in the case where your installation is not connected to the grid, what happens when you’re not home during the day to use the electricity your system produces?

A battery will store the electricity produced when you’re not home.

So, a solar battery has become a vital component of a solar installation.

The key factors to consider when choosing a solar battery are outlined in the table below

TABLE 2. FACTORS TO CONSIDER WHEN CHOOSING A BATTERY

General System Maintenance

Probably the most important maintenance you’ll need to do is to always keep the surface of your solar panels free of dust, leaves, ice, bird poo, etc.

Such elements can lower the performance of your solar installation by reducing the amount of sunlight reaching your panels.

Most solar systems have integrated monitoring software that enables you to monitor the system’s performance and detect faults and failures.

Lastly, you should have your solar installer periodically inspect your installation to ensure that all the components are always in excellent working conditions.

BENEFITS OF SOLAR HOME SYSTEMS

There are many benefits of going solar at your home, whether on a small scale or a large scale.

These benefits include the following:

• With off-grid systems you avoid the high cost of connecting to the national grid, especially in big cities and towns
• You worry less about frequent power outages because you can generate your own power
• Since you avoid or reduce consumption of electricity from the national grid, you can cut your energy bill substantially
• You get after-sales service guarantees from reputable installation companies
• A solar installation increases the value of your home, because property valuers consider it to be a home improvement installation.

BENEFITS OF COMMERCIAL SOLAR INSTALLATION

In addition to most of the residential installation benefits listed above, commercial solar installation benefits include:

• Your capital investment in a solar installation is tax deductible
• You can run your manufacturing plant round-the-clock and don’t have to stop production any time because of lack of electricity
• Solar installations require little or no maintenance, so your operating costs are much lower when compared to the costs of running a diesel generator
• You can write-off the investment in a solar installation or any impairment to it.