Energy shapes national economies and social development. Indeed, energy powers daily lives; runs factories, fuels
vehicles, heats and cools homes and businesses, amongst others. The stability and reliability of energy supply
systems is even more appreciated now as many people are becoming more dependent on electronic data and
Electricity supply that can lead to sustainable development has to be reliable, affordable, economically viable,
socially acceptable and environmentally sound for the socio-economic well-being of all. Reliable electricity access
is the life-wire of any country. Without energy there is no economy. Nigeria is presently faced with the challenge
of providing sustainable, adequate, reliable and efficient electricity supply to residential, commercial and
This situation has adversely affected the social and economic life of the citizenry. The contemporary deteriorating
power condition in which the nation is entangled, is as a result of the over dependence on fossil fuels, to fuel the
electricity generating plants. Consequently, sustainable renewable energy resources, in spite of their abundance,
were relegated to the back, contributing little to the overall Nigeria energy supply mix.
Read more: Future of solar
Successive Nigerian governments have made some giant efforts to solve this dreadful energy crisis that threatens
the economic growth of the nation, but all efforts have proved abortive. One of these efforts, is the quest to join the
world’s 20 most developed economies. The present government has set an energy policy that seeks to exploit the
abundant renewable energy sources to complement fossil fuel, with the hope of improving the current power
supply in the country.
Solar radiation represents the largest energy flow entering the terrestrial ecosystem. After reflection and
absorption in the atmosphere, some 100,000TW usually hit the surface of the Earth and undergo conversion
to all forms of energy used by humans, with the exception of nuclear, geothermal and tidal energy.
This resource is enormous and corresponds to almost 6,000 folds, the current global consumption of primary
energy (13.7TW). Thus, solar energy has the potential of becoming a major component of a sustainable energy
portfolio, with constrained greenhouse gas emissions. Solar radiation being abundantly present in Nigeria, is
one area of focus among the renewable energy resources that can be harnessed to solve Nigeria’s power crisis.
Nigeria receives an average solar radiation of about 7.0kWh/m2 (25.2MJ/m2 per-day) in the far north and about
3.5kWh/m2 per day (12.6MJ/m2 per day) in the costal latitudes. The estimate of potential solar energy in Nigeria,
with 5% device conversion efficiency is 5.0×1014 KJ of useful energy annually. This is equivalent to about
258.62million barrels of oil produced annually and about 4.2×105 GWh of electricity production annually, in
Effective harnessing and utilization of this abundant solar radiation, using solar energy technologies to augment
energy supply from fossil fuel energy resources (using cleaner fossil fuel technologies), would enhance availability
of energy for socio-economic activities and subsequently lead the nation to realize its 2020 Transformation Agenda.
The sun’s structure and characteristics determine the nature of the energy it radiates into space. The sun is a
sphere of intensely hot gaseous matter with a diameter of 1.39x109m and is, on the average, 1.5x1011m from
the earth. As seen from the earth, the sun rotates on its axis about once every 4 weeks. However, it does not
rotate as a solid body; the equator takes about 27 days and the Polar Regions take about 30 days for each
rotation. The sun has an effective blackbody temperature of 5777K. The temperature in the central interior r
egions is variously estimated at 8×106 to 40x106K and the density is estimated to be about 100 times that of
The sun is, in effect, a continuous fusion reactor with its constituent gases as the “containing vessel” retained by
gravitational force. Solar radiation is an electromagnetic wave emitted by the sun’s surface that originates in the
bulk of the Sun where fusion reactions convert hydrogen atoms into helium. Every second, 3.89x1026J of nuclear
energy is released by the sun’s core. This nuclear energy flux is rapidly converted into thermal energy and
transported towards the surface of the star where it is released in the form of electromagnetic radiation.
The power density emitted by the Sun is of the order of 64MW/m2¬ of which 1370W/m2 reach the top of the
earth’s atmosphere with no significant absorption in the space. The latter quantity is called the solar constant.
Radiation reaching the Earth’s surface is altered by a number of factors, namely: the inclination of the earth’s
axis and the atmosphere that causes both absorption and reflection of part of the incoming radiation.
Accounting for absorption by the atmosphere, reflection from cloud tops, oceans, terrestrial surfaces and rotation
of the Earth (day/night cycles), the annual mean of the solar radiation reaching the surface, is 170W/m2 for the
oceans and 180W/m2 for the continents. Of this, about 75% is direct light, the balance of which is scattered by
air molecules, water vapour, aerosols and clouds.
Solar Radiation in Nigeria
Nigeria lies within a high sunshine belt and thus has enormous solar energy potentials. The mean annual average
of total solar radiation varies from about 3.5 KWh (m2 per day) in the costal latitudes to about 7 KWh (m2 per day
) along the semi arid areas in the far North. On the average, the country receives 19.8MJ (m2 per day). Average
sunshine hours are estimated at 6hrs per day.
Given an average solar radiation level of about 5.5KWh (m2 per day) and the prevailing efficiencies of commercial
solar-electric generators, then if solar collectors or modules were used to cover 1% of Nigeria’s land area of
923,773km2, it is possible to generate 1850x103GWh of solar electricity per year, which is over one hundred
times the current grid electricity consumption level in the country.