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.
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
It converts the sunlight into direct current (DC) electricity.
The solar panel is the most important component of your solar system. A collection of solar panels is called a solar array.
A solar inverter converts the DC electricity from your solar array into alternating current (AC) electricity that your electrical items can use.
An inverter is needed when your system is connected to a grid (on-grid). You can use one central inverter for all your panels combined or use a micro-inverter for each solar panel.
A battery stores the power your solar array generates during the day if you’re not around to use it. It also provides this stored power to you at night when your solar system is not generating electricity.
You can use a battery for both on-grid and off-grid situations. The battery serves as your back-up for when grid electricity is not available or is too expensive. The more batteries you use, the more back-up storage you can have.
It manages the AC electricity that goes from your array into your batteries. It also prevents a backward flow of electricity from the batteries to the solar panels.
A charge controller is needed when your system is not connected to a utility grid (off-grid).
Mount (or “Rack”)
A mount is the support your solar array sits on before you place it on the roof or on the ground.
Whether your solar array is on the ground or on the roof you need to elevate it so air can circulate around the panels to cool them.
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:
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).
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.
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.
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.
Shading from a building or a tree will reduce the efficiency of your array, whether the panels are ground-mounted or rooftop mounted.
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.
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.
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.