The document outlines the distinction between renewable and non-renewable energy sources, emphasizing the importance of renewable energy for sustainable development. It details various renewable energy technologies such as hydropower, solar energy, wind power, and biomass, highlighting their potential, advantages, and current applications. Additionally, it discusses emerging technologies and challenges in the renewable energy sector, indicating a significant shift towards cleaner energy resources to combat climate change.

1. MCS 501 – CLIMATE CHANGE
AND ENERGY
MODULE 1

2. Renewable and non-renewable energy

3. Renewable and non-renewable energy
Fossil energy carriers are hydrocarbon substances and include
 crude oil,
 natural gas,
 tar sands and coal.
 They are depletable at any rate of consumption and therefore non-renewable.
 Also when ordinarily consumed, fossil fuels upset the natural balance of carbon dioxide (CO2) in the
atmosphere and thus contribute to global warming.
Renewable energy carriers are resources, which are available on a continuous or
periodic/cyclic basis and include
solar,
wind,
hydro,
tidal,
wave,
geothermal, and
biodegradable biomass (fuelwood, animal and crop residues, energy crops, etc.).
 They are non-depletable on consumption and suitable for driving sustainable development
 Apart from large hydro, and some form of biomass, renewable energy utilization has relatively little
negative effects on the environment. They are therefore energy resources suitable for sustainable
development.

4. Importance of Renewable Energy
• They have important advantages which could be
stated as follows:
Their rate of use does not affect their availability in future,
thus they are inexhaustible.
The resources are generally well distributed all over the
world, even though wide spatial and temporal variations
occur.
Thus all regions of the world have reasonable access to one
or more forms of renewable energy supply.
 They are clean and pollution-free, and therefore are
sustainable natural form of energy.
 They can be cheaply and continuously harvested and
therefore sustainable source of energy

5. Essentially, hydropower systems rely on the potential energy
difference between the levels of water in reservoirs, dams or lakes
and their discharge tail water levels downstream. The water
turbines which convert the potential energy of water to shaft
rotation are coupled to suitable generators.
Hydropower includes conventional run-of-river and storage
reservoirs, pumped storage reservoirs, and the new emerging
technologies of ocean wave, tidal, and hydrokinetic energy.
The potential increase in U.S. hydropower generation capacity is
estimated at 23 GW by 2025, including 10 GW from conventional
hydropower, 3 GW from new hydrokinetic technologies, and 10
GW from ocean wave energy devices. If implemented, this growth
in hydropower would represent a 25 percent increase over the
existing U.S. hydropower generation capacity of 96 GW.
Hydropower

6. The hydropower potential of Nigeria is very high and
hydropower currently accounts for about 29% of the total
electrical power supply. The first hydropower supply station in
Nigeria is at Kainji on the river Niger where the installed
capacity is 836MW with provisions for expansion to 1156 MW.
A second hydropower station on the Niger is at Jebba with an
installed capacity of 540 MW. An estimate (Aliyu and Elegba,
1990) for rivers Kaduna, Benue and Cross River (at Shiroro,
Makurdi and Ikom, respectively) indicates their total capacity
to stand at about 4,650 MW.
Estimates for the rivers on the Mambila Plateau are put at
2,330MW. The overall hydropower resources potentially
exploitable in Nigeria is in excess of 11,000MW.
Hydropower

7. Large hydro schemes have predominantly been the class of schemes
in use prior to the oil crisis of 1973
Many developed and developing countries have opted for small-scale
hydropower with appreciable savings made over the otherwise
alternative of crude oil.
Hydropower plants that supply electrical energy between the range of
15kW to 15MW are mini-hydro while those supplying below 15kW are
normally referred to as micro-hydro plants (Sambo and Taylor, 1990).
Small-scale (both micro and mini) hydropower systems possess the
advantage, over large hydro systems, that problems of topography are
not excessive.
Small hydropower systems can be set up in all parts of the country so
that the potential energy in the large network of rivers can be tapped
and converted to electrical energy. In this way the nation's rural
electrification projects can be greatly
Hydropower

8. Solar energy
The most promising of the renewable energy sources in
view of its apparent limitless potential is solar energy.
The sun radiates its energy at the rate of about 3.8 x 1023
kW per second.
Most of this energy is transmitted radially as
electromagnetic radiation which comes to about
1.5kW/m2
at the boundary of the atmosphere.
After traversing the atmosphere, a square metre of the
earth's surface can receive as much as 1kW of Solar
power.

9. Studies relevant to the availability of the solar energy resource
in Nigeria (Sambo, 1986, 1988; Sambo; Doyle and Sambo, 1988;
and Folayan, 1988, Okogbue et al, 2008 etc) have fully indicated
its viability for practical use and are now in use.
Although solar radiation intensity appears rather dilute when
compared with the volumetric concentration of energy in fossil
fuels, it has been confirmed that Nigeria receives 5.08 x 1012
kWh of energy per day from the sun and if solar energy
appliances with just 5% efficiency are used to cover only 1% of
the country's surface area then 2.54 x 106
MWh of electrical
energy can be obtained from solar energy.
This amount of electrical energy is equivalent to 4.66 million
barrels of oil per day.
Solar energy

10. Solar energy conversion technologies are divided into
two broad groups namely solar-thermal and solar
photovoltaics.
In solar thermal applications, solar energy, as
electromagnetic waves, is first converted into heat
energy.
The heat energy may then be used either directly as
heat, or converted into 'cold', or even into electrical or
mechanical energy forms.
Typical such applications are in drying, cooking, heating,
distillation, cooling and refrigeration as well as electricity
generation in thermal power plants through
Concentrating Solar Power (CSP) systems
Solar energy conversion

11. Solar Thermal Generation
of Electricity
• Mirrors are used to concentrate sunlight either onto a
line focus or a point focus
• Steam is generated, and then used in a steam turbine
• In some cases, concentrated solar energy heats a
storage medium (such as molten salt), so electricity
can be generated 24 hours per day using stored heat
at night
• Best in desert or semi-desert regions, as only direct-
beam solar radiation can be used

12. Solar Thermal Generation
of Electricity (Contd.)
• The radiation available for use by concentrating solar thermal power (CSTP)
systems is referred to as the ‘direct normal’ radiation – the annual value is the
irradiance on a surface that is always at 90o
to the sun’s rays
• As only the direct beam radiation can be used, the peak irradiance that can be
used by CSTP is typically about 850 W/m2
, compared to 1000 W/m2
for PV systems
• Thus, peak power capacity for CSTP is given assuming a direct beam irradiance of
850 W/m2
rather than 1000 W/m2
• The annual capacity factor is equal to the annual average direct normal irradiance
(in W/m2
) divided by 850 W/m2
(in the same way that the annual capacity factor
for PV is given by the annual average irradiance on the module divided by 1000
W/m2
)

15. Concentrating Solar Power (CSP)
systems comprises multiple
technologies including parabolic
troughs, dish-engine systems, and
heliostat-based power towers.
One of the advantages of CSP is its
suitability for hybridization with
conventional natural gas combined
cycle or coal plants, and the use of
heat storage or auxiliary fuel firing to
achieve full power and remove
intermittency from operation with
insufficient sunlight.
Concentrating Solar Power

16. Today, over 7 GW of
CSP are installed
worldwide.
Recently installed and
planned facilities in the
U.S., Mexico, Europe,
Middle East, Asia, and
Africa are 4.56 GW.
With sufficient direct solar
radiation, it is possible that
CSP could become the
lowest cost utility for the
southwestern U.S. & other
areas of the world.
Concentrating Solar Power

17. PV Electricity
•Electromagnetic radiation (including light)
comes in packets called photons, each with
energy hv, where h=Plank’s constant and v is
the frequency of the radiation
•Electrons in an atom exist in different energy
levels
•A photon can bump an electron to a higher
energy level if the energy of the photon
exceeds the difference in energy from one level
to the next

18. PV electricity (continued)
• When a solid forms, two outer energy bands are formed, often
separated by a gap
• The lower energy band is called the valence band, the upper the
conduction band
• In a conductor, electrons occur in both bands and they overlap
• In an insulator, the valence band is filled and the conduction band
is empty, and the two bands do not overlap
• In a semi-conductor, electrons occur in both bands and there is a
small gap between the bands
• Silicon is a semi-conductor with a valence of 4 (4 electrons in the
outer shell)

19. PV electricity (continued)
•Two semiconductor layers are used –
•one layer (called the n-type layer) is doped
with atoms have an valence of 5 (the extra
electron is not taken up in the crystal lattice
and so it free to move), and
•the other layer (called the p-type layer) is
doped with atoms having a valence of 3, so
there are empty electron sites (called holes)
•The juxtaposition of the n- and p layers is
called a p-n junction.

20. Figure 2.6 Steps in the generation of electricity in a photovoltaic cell
Source: US EIA (2007, Solar Explained, Photovoltaics and Electricity)

21. Figure 2.7 Layout of a silicon solar cell
Source: Boyle (2004, Renewable Energy, Power for a Sustainable Future, 65-104, Oxford University Press, Oxford)

22. In solar photovoltaic (PV) applications, the
solar radiation is converted directly into
electricity.
The most common method of doing this is
through the use of a Solar Photovoltaic (PV)
system
A PV system is a system that converts
sunlight into usable electricity as well as storing
it if needed
The heart of any Solar PV system is the solar
cell, which is the actual material that turns
sunlight (photons) into electricity (electrons).
PV cells are generally quite small and are
connected in series to form a Photovoltaic panel
or module.
These in turn can be connected together to
form Photovoltaic arrays that produce more
power.
Photovoltaics

23. Components of a PV system
• Module – consists of many cells wired
together
• Support structure
• Inverter – converts DC module output to AC
power at the right voltage and frequency for
transfer to the grid
• Concentrating mirrors or lens for
concentrating PV systems

24. Components of a PV system
In addition to the solar panel, the system requires other
components to store electricity, convert it into usable
forms, a frame to support the panels and other
components. These components are collectively known
as the Balance of System
The technique was first observed in 1939. Its
development had been closely tied to the space
programme of the western world.
PV modules can be used for utility-scale electricity
generation; however, they are used more commonly as a
distributed power source on buildings.

25. Types of PV cells
•Single-crystalline
•Multi-crystalline
•Thin-film amorphous silicon
•Thin-film compound semiconductors
•Thin-film multi-crystalline
•Nano-crystalline dye-sensitized cells
•Plastic cells

26. Thin-film compound semiconductors
•Cadmium telluride (CdTe)
•Copper-indium-diselenide (CuInSe2,
CIS)
•Copper-indium-gallium-diselenide
(CIGS)
•Gallium arsenide (GaAs)

27. Factors affecting module efficiency
•Solar irradiance – efficiency peaks at
around 500 W/m2
for non-
concentrating cells
•Temperature – efficiency decreases
with increasing temperature, more so
for c-Si and CIGS, less for a-Si and CdTe
•Dust – can reduce output by 3-6% in
desert areas

28. Individual PV cells have a solar-to-electric conversion efficiency of 15
to 20 percent; however, the efficiency of modules combining many
cells is 10 to 15 percent for crystalline silicon and 5 to 10 percent for
thin-films.
The grid-connected solar PV capacity grew on average more than 60
percent per year but total installed capacity remains low, only 3.1
GW at the end of 2005.
 Japan, Germany, and the U.S. account for more than 90 percent of
installed PV capacity in the Organization for Economic Cooperation
and Development countries.
 The challenge for greater implementation of PV is achieving lower
cost systems.
 In recent times, the commercial viability of photovoltaic systems
have been recognized and concerted international efforts in R & D
have led to increase in efficiency and reliability as well as reductions
in cost.
Photovoltaics

32. Wave energy
Wave energy is among the list of renewable energy that
is being developed in recent times
Wave energy the energy produced for domestic or industrial use by
harnessing and converting the energy of sea.
New Jersey developer, Ocean Power Technologies is pioneering this in the
US by launching the nation’s first commercial wave power farm. The wave
power farm operates on the wave energy that is created when a float on
buoy flows with the natural up and down movement of the waves.
A Scottish Wave Energy company Archimedes Wave Swing (AWS) Ocean
Energy Ltd based in Alnees was reported to have in February, 2007
secured a ₤2.128 million funding from the Scottish Government . This is
just one of a ₤13 million support package for Scottish marine energy
developers funded by the Scottish executive, which aims to put Scotland as
a world leader in marine energy
Key challenges for hydropower include continued development of new
technologies to harness ocean, wave, tidal, and hydrokinetic energy, and mitigate
environmental impacts associated with larger-scale conventional hydropower
generation.

33. Geothermal
Generally, geothermal electricity production is practical only where underground steam
or water exists at temperatures greater than 100°C. Global geothermal electric-
generating capacity is approximately 9 GW with most of it concentrated in Italy, Japan,
New Zealand, and the U.S..
According to the Energy Information Administration, the U.S. design capacity is 3 GW and
geothermal electric generation in 2006 was 14,842 GWh.
Most U.S. geothermal plants are located in California and Nevada. Existing plants operate
90 to 98 percent of the time and can provide base load electricity.
Today, geothermal electricity is produced using the hydrothermal resources (nominally
hot water and steam) accessible within 3 km of the earth’s surface.
Growth of conventional geothermal energy is expected to be modest, and the resource
base can only be expanded by drilling to greater depth, and development of technologies
for extraction of the thermal energy stored in dry rock.
This resource is vast, but it is currently not economical to tap because of its depth, low
permeability, and
lack of water as a carrier fluid.

34. Biomass
The total mass of living organisms in a given area or volume;
recently dead plant material is often included as dead biomass.
The greatest use of biomass for power today is direct firing of post
consumer residues of the forest industry.
Outside the pulp and paper industries, only a small amount of
biomass is used to produce electricity.
Commercially available technologies for converting biomass to heat
and electricity include fixed-bed combustion, fluidized beds, dust
combustion, biomass and coal co-firing, and several types of
gasification systems.
At present, interest in biomass energy is focused primarily on the
production of liquid fuels for transportation.
The most significant challenge to expand biomass use beyond
combustion is developing the technologies to process lignocellulosic
(non-food crop) biomass and efficient use of arable land which is
needed for food crops.

35. Renewable Hydrogen Fuel
 Nano-trees Electrical Engineers at the
University of California San Diego are
building artificial nano-trees that will mimic
real life plants to take in sunlight , water and
CO2 and produce hydrogen fuel. The engineers
are using cheap materials such as zinc oxide
and silicon to deliver cheap hydrogen fuel,
hopefully, one day on a massive scale
Toyota, Mercedes are already buying a
massive production of hydrogen cars in the
2020s

36. Wind
Wind power is the fastest growing source of renewable electricity. In 2006,
the installed capacity worldwide was 75 GW and wind power supplied
more than 25,000 GWh of electricity (GWEC 2008).
Wind power capacity grew by 50 percent in the U.S. in 2008 to 25,170
megawatts of installed capacity, enough electricity to power nearly 7
million households (GWEC 2009).
Most modern installed turbines have 84 m hub heights and a rotor
diameter of 67 m. Modern Type 3 turbines have advanced mechanical-to-
electrical conversion characteristics to handle grid interface issues.
The evolution of controls has eased the integration of wind power plants
with the utility system.
As wind energy approaches penetration levels of 20 percent, grid dispatch
ability may limit growth unless improved electric grid management
techniques and cost-effective storage technologies are available (DOE
2008b; Zavadil et al. 2007.)8 Investments in transmission capacity and
improvements in transmission are needed to handle intermittency and
transmission over large distances.