BNB 31403

ELECTRICAL & ENERGY SUPPLY

RENEWABLE ENERGY

DR. NORAIN BINTI SAHARI

Renewable energy also known as
secondary sources to produce electricity.
The examples of renewable energy are:

Hydropower
Solar Power
Geothermal Power
Biomass
Wind Power
Hydropower
If you've ever stood in a fast–moving stream, under a waterfall, or on the
ocean shore as waves come crashing in, then you've felt the power of the
water. The energy from moving water can be used to create electricity in
several different ways.
• Hydropower plants capture
the energy of falling water to
generate electricity.
• A turbine converts the kinetic
energy of falling water into
mechanical energy.
• Then a generator converts
the mechanical energy from
the turbine into electrical
energy.

Kenyir hydro plant first operated at

1987 was the largest hydro plant in
Malaysia.
Solar Power
Why is daytime brighter and warmer than
nighttime? The answer is simple: solar energy.
Solar energy is simply the light and heat that
come from the sun.
• Solar panel absorb the sun’s
energy and convert it into
DC electricity.
• The solar inverter converts
DC electricity to AC
electricity.
• Electricity flows through
home, powering electronic
devices.
• Excess electricity produced
by solar panels is fed to the
electric grid.

largest solar project in Malaysia uses

230,000 solar panels installed on 98
hectares of land in Mukim Tanjung 12,
Sepang.
Geothermal Power
If you were dig a big hole straight down into the Earth,
you would notice the temperature getting warmer the
deeper you go. That's because the inside of the Earth is
full of heat. This heat is called geothermal energy.

• Geothermal power work by piping hot

steam from underground reservoirs
directly into turbines from geothermal
reservoirs, which power the generators
to provide electricity.
• After powering the turbines, the steam
condenses into water and is piped back
into the earth via the injection well.

Green Energy Sdn Bhd (TGE) is on

track to develop Malaysia’s first
geothermal power plant project in
Tawau, Sabah, in 2019.
There are three principle ways of converting geothermal
into electricity:

 1. Dry-steam power plants

 2. Flash-steam power plants
 3. Binary power plants
Dry-Steam Power Plant
• Most common types of
geothermal power plants.
• They work by piping hot
steam from underground
reservoirs directly into turbines
from geothermal reservoirs,
which power the generators
to provide electricity.
• After powering the turbines,
the steam condenses into
water and is piped back into
the earth via the injection
well.
Flash-steam Power Plant

• Flash steam plants pump

hot water at a high pressure
from below the earth into a
“flash tank” on the surface.
• The flash tank is at a much
lower temperature, causing
the fluid to quickly “flash”
into steam.
• The steam produced
powers the turbines.
• The steam is cooled and
condenses into water,
where it is pumped back
into the ground through the
injection well.
Binary Power Plant • In these binary cycle plants, the
main difference is that the water
or steam from below the earth
never comes in direct contact
with the turbines.
• Instead, water from geothermal
reservoirs is pumped through a
heat exchanger where it heats a
second liquid.
• This second liquid is heated into
steam, which powers the turbines
that drives a generator.
• The hot water from the earth is
recycled into the earth through
the injection well, and the second
liquid is recycled through the
turbine and back into the heat
exchanger where it can be used
again.
Biomass
Biomass is a fancy name for material from plants and animals. Some kinds
of biomass can be burned to produce energy. One common example is
wood. Biomass contains stored energy. That's because plants absorb energy
from the sun through the process of photosynthesis. When biomass is
burned, this stored energy is released as heat.

• Burning biomass to produce heat and

make steam.
• Steam turns the blades of huge
turbines which spin generators to
create electricity.
• A transformer increases the voltage to
send electricity over distribution lines.
• Then local transformers reduce the
voltage for residential user.
Wind Power
The wind can blow your hat off, rustle the trees, and even power your
television. For thousands of years, people have used windmills to grind grain
and pump water. Today, modern machines called wind turbines are used to
make electricity. To produce a lot of electricity, many wind turbines can be
placed together on wind farms. Good sites for wind farms are often found on
windy hilltops, open plains, and shorelines.

• As the wind blows over the blades of a wind

turbine, it causes the blades to lift and rotate.

• The rotating blades turn a shaft that is

connected to a generator.

• The generator creates electricity as it turns.

Wind turbine at Pulau Perhentian

that was built on 2006
Exercise

Analyze the power converted from the wind into rotational energy in the turbine by using
the following data:

Blade length : 500 cm

Wind speed : 10 m/sec
Air density : 1.23 kg/m3
a) For power coefficient of 45%
b) For power coefficient of 55%
 General formula for wind power.
a) For power coefficient of 45% ρ = density of air
A = Swept area
Power available v = velocity of wind
Cp = Overall turbine efficiency
= ½ ρAv3Cp

= ½ x 1.23 x 7854 x 103 x 0.45 Swept area, A

= 2.17MW = πr2
= π x 502
= 7854m2

b) For power coefficient of 55%

Power available
= ½ ρAv3Cp
= ½ x 1.23 x 7854 x 103 x 0.55
= 2.65MW

High efficiency will increased the power output!