renewable power plants materials

1. UNIT-4
(Hydro Electric Power Plants – Classification,
Typical Layout and associated components
including Turbines. Principle, Construction
and working of Wind, Tidal, Solar Photo
Voltaic (SPV), Solar Thermal, Geo Thermal,
Biogas and Fuel Cell power systems.)
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Hydro electric power plants
• Hydroelectric
hydropower) is
power (often called
considered a renewable
energy source. A renewable energy source
is one that is not depleted (used up) in the
production of energy. Through
hydropower, the energy in falling water is
converted into electricity without “using up”
the water.

3. Hydropower energy is ultimately derived from the
sun, which drives the water cycle. In the water
cycle, rivers are recharged in a continuous cycle.
Because of the force of gravity, water flows from
high points to low points. There is kinetic energy
embodied in the flow of water.
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6. components including Turbines
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7. Biomass
□ Composition of Municipal Solid Waste
□ Energy Retrieval from Recycling
□ Incineration and Incinerator Ash
□ Secure Landfills
□ Efficiency of Conversion of Sunlight into Biomass
□ Methane Digesters
□ Alternative Biomass Fuels for Vehicles
□ Wood Combustion
□ Energy Plantations
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8. Biomass to
Fuel
Conversions
Results:
Alcohol (Ethanol)
Biogas (Methane)
Syngas
Gasoline (Biocrude)
Diesel Fuel (Plant Oil)
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• Fuel wood
• Charcoal
• Agricultural waste
• Wood pellets
• Biogas
• Bio-ethanol (equivalent of gasoline)
• Biodiesel (equivalent of diesel), and
• Bioelectricity
GENERAL ORGANISATION OF
TECHNOLOGIES

10. Example of Biogas
Production
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11. Biomass direct combustion
Direct combustion:
Pyrolysis: thermal decomposition into gas or liquid
Involves high temperatures (500-900°C), low oxygen
Biochemical processes:
Anaerobic digestion by methanogens
Controlled fermentation produces alcohols:
Ethanol (grain alcohol)
Methanol (wood alcohol)
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12. Electricity Generation from
Biomass
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13. Conversion Technologies
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14. Biochemical Conversion
• Plant matter – hemicellulose, cellulose, lignin
• Pretreatment
• Hydrolysis
• Sugar Fermentation
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15. Thermo-chemical Conversion
• Gasification,
Pyrolysis, Direct
Hydrothermal
Liquefaction
• Carbon monoxide and
Syngas (Hydrogen)
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16. Anaerobic Digestion
• Biogas Platform -
Methane
• Decomposition -
microorganisms
• Anaerobic Digesters
• Four Main Processes
• Uses wastes and turns
into valuable compost
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17. Optimum Operating Temperature
35°C, maximum liters of methane per day, best retention time?
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Biomass Today
• Construction of large-scale Bio-refineries
• Improved Catalysis Technology
– High Selectivity
– Less Energy Intensive Conditions
– Reduction of Unit Operations
• Combined Government and Industry Efforts

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Biomass combustion processes
• What is biomass?
• Significance of biomass combustion
• Classification of biomass
• Classification of biological solid fuels
• Combustion processes
• Direct combustion
• Advantages and disadvantages
• Pyrolysis and gasification
• Conclusion

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Significance of biomass
combustion
• Use of biomass for energy causes no net increase in carbon
dioxide emissions to the atmosphere and does not contribute to
the risk of global climate change
• Growing plants remove carbon from the atmosphere through
photosynthesis
• If the amount of new biomass growth balances the biomass used
for energy, bio-energy is carbon dioxide “neutral”
• Globally, biomass meets about 14 percent of the world’s energy
needs

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What is Biomass Gasification?
Basic Process Chemistry
• Conversion of solid fuels into combustible gas
mixture called producer gas (CO + H2 + CH4)
• Involves partial combustion of biomass
• Four distinct process in the gasifier viz.
• Drying
• Pyrolysis
• Combustion
• Reduction
BIOMASS GASIFIERS

22. Types of gasifiers
Updraft Down draft
1.
2.
Generates tar Generates clean gas
Suitable for thermal application Suitable for electricity application
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23. Gasification technology
• The elements
Reactor
Cooling and
Cleaning system
Engine
Producer gas
CO: 20 + 1%; CH4 : 3 + 1%, H2 : 20 + 1%,
CO2 : 12 + 1% and rest N2.
Performance
Biomass consumption : 1 – 1.3 kg/kWh 23

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Barriers for technology spread
Like any new technology, even biomass
gasification faces key barriers for the spread
– Technical
– Information
– Policy and Institutional
– Financial
– Human Resource

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Applications
Power Generation Thermal Applications
• Irrigation Pumping
• Village Electrification
• Captive Power (Industries)
• Grid-fed Power
• Simultaneous Charcoal and
Power Production
• Hot Air Generators
• Dryers
• Boilers
• Thermic Fluid Heaters
• Ovens
• Furnaces & Kilns

26. Biogas plants
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What Is Biogas?
Biogas is a gas mixture which is generated when
organic compounds are fermented in the absence
of air (anaerobic fermentation). This gas mixture
is mainly made of carbon dioxide (CO2) and
methane (CH4). Methane is a combustible gas,
which means it can be burned. It can be used as
a fuel for cooking and lighting.

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The Biological Gas Plant
• A plant to collect biological gas has five components: the inlet, the
fermentation chamber, the gas, the gas storage bag or tank, and the outlet
and the exit pipe through which the gas is removed.
• Organic matter such as manure (human or animal), duckweed or rice straw
is brought into the fermentation chamber (through the inlet).
• The process of anaerobic fermentation will take place here to generate
biological gas (biogas). It will also produce a substrate rich in nutrients
which can be used as organic fertilizer or fish feed.
• The processing of manure, organic rubbish and wastewater in the plant
helps to keep the environment clean. There is no longer any bad smell
from sewage or livestock manure.
• Cooking by biogas is much cleaner than cooking over a wood fire, and
there is no smoke to cause lung problems and eye diseases.

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The Technology
• Begin by loading the fermentation chamber with the materials to be
fermented (manure or other wastes). You should begin with an initial
load of 300 - 500 kg of materials for each cubic meter of the
fermentation chamber.
• This needs to be supplemented by an additional 8- 10 kg each day for
each cubic meter of the fermentation chamber. The gas output will be
250 - 400 liters for each cubic meter of the chamber.
• Expressed another way, 1 kg of manure will have a gas yield of 30 - 60
liters/day, for several days. The gas yield from 1 kg of water hyacinth
will be 40 - 50 liters/day, for several days.
• One cubic meter of gas (= 1000 liters) is enough to cook the day's food
for a 6 - 7 member family, or provide lighting for 4 - 5 hours. It could
replace one liter of petrol to operate a 400W electric generator for two
hours.

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The Precautions
• The plant must be tested to make sure it is water-tight and gas-tight.
• Enough fresh material must be added before it is used every day.
• There must be a water source to provide enough water to clean the livestock
pens regularly, to provide fresh material for the fermentation chamber system.
(Each liter of manure needs 1 - 3 liters of water).
• The plant must be equipped with a safety valve or U-shaped barometer.
• Chemicals such as detergents or pesticides must not be put into the
fermentation chamber.
• After fresh manure and water is added to the fermentation chamber, the valve
should be opened so the gas can escape. At this stage, the gas is mainly carbon
dioxide. This should be done once or twice, before the biogas plant comes into
use for biogas production.
• The gas from the fermentation chamber is not used directly, but is stored in an
auxiliary gas tank protected by a safety valve. It is this auxiliary gas tank, not
the main gas tank, which is connected to any domestic appliances.

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What is Biogas Digestion?
• Biogas Digestion is the process of taking
biogas to produce electricity, heat, or hot
water
• Biogas means a gas formed by carbon
dioxide and methane from breakdown of
organic materials such as manure.
Digesters

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What is a Digester?
• Digester is a vessel or container where the
biogas process takes place. Bacteria breaks
down manure or other waste products to
create biogas. Products may be fed into the
chamber such as manure or the container
could be used to cover a place that is
already giving off biogas such as a swamp
or a landfill.

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Reasons of Interest in Biogas
Anaerobic Digester systems
• Improved Technology in systems has led
to reliability
• Good way to manage manure given the
odor and environmental concerns
associated with manure
• Government has subsidized programs
for systems
• Potential to sell credits to utilities and
utilities continue interest in green energy

34. Design of a Digester
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How Digester Works
• Temperature must be kept between 65 degrees and 150 degrees
• 4 Types of bacteria breakdown the waste
– Hydrolytic breaks organic material to simple sugar and
amino acids
– Fermentative then converts to organic acids
– Acidogenic convert to carbon dioxide, acetate, and
hydrogen
– Methanogenic produces biogas

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What is Ethanol Fuel?
• Ethanol is an alcohol found in alcoholic beverages.
• It is most often used as motor fuel mainly as bio-fuel
additive for gasoline.
• Ethanol, unlike petroleum, is claimed to be a form of
renewable energy that can be produced from agricultural
crops such as sugar cane, potato, and corn.
• Ethanol (ethyl alcohol, grain alcohol) is a clear, colorless
liquid with a characteristic, agreeable odor.
• In dilute aqueous solution, it has a somewhat sweet flavor,
but in more concentrated solutions it has a burning taste.
Ethanol production

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ETHANOL
Physical properties:
• Colorless liquid.
• Pleasant alcoholic odor detectable at 49 to 716
ppm.
• Miscible with water and most organic solvents.
• Melting Point (°C): -114.1
• Boiling Point (°C): 78.3
• Specific Gravity: 0.789
• Vapor Density: 1.6

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The major steps in the dry mill process are:
• 1. Milling. The feedstock passes through a hammer
mill which grinds it into a fine powder called meal.
• 2. Liquefaction. The meal is mixed with water and
alpha-amylase, then passed through cookers where the
starch is liquefied. Heat is applied at this stage to
enable liquefaction. Cookers with a high temperature
stage (120-150 degrees Celsius) and a lower
temperature holding period (95 degrees Celsius) are
used. High temperatures reduce bacteria levels in the
mash.

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3.Saccharification. The mash from the cookers is
cooled and the secondary enzyme (gluco-amylase) is
added to convert the liquefied starch to fermentable
sugars (dextrose).
4.Fermentation. Yeast is added to the mash to
ferment the sugars to ethanol and carbon dioxide.
Using a continuous process, the fermenting mash is
allowed to flow through several fermenters until it is
fully fermented and leaves the final tank. In a batch
process, the mash stays in one fermenter for about 48
hours before the distillation process is started.

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5.Distillation. The fermented mash, now called beer, contains about
10% alcohol plus all the non-fermentable solids from the corn and
yeast cells. The mash is pumped to the continuous flow,
multi-column distillation system where the alcohol is removed from
the solids and the water. The alcohol leaves the top of the final
column at about 96% strength, and the residue mash, called stillage,
is transferred from the base of the column to the co-product
processing area.
6.Dehydration. The alcohol from the top of the column passes
through a dehydration system where the remaining water will be
removed. Most ethanol plants use a molecular sieve to capture the
last bit of water in the ethanol. The alcohol product at this stage is
called anhydrous ethanol (pure, without water) and is approximately
200 proof.

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7.Denaturing. Ethanol that will be used for fuel must
be denatured, or made unfit for human consumption,
with a small amount of gasoline (2-5%). This is done at
the ethanol plant.
8.Co-Products. There are two main co-products
created in the production of ethanol: distillers grain and
carbon dioxide. Distillers grain, used wet or dry, is a
highly nutritious livestock feed. Carbon dioxide is
given off in great quantities during fermentation and
many ethanol plants collect, compress, and sell it for
use in other industries.

46. Bioethanol Market
Bioethanol
bus
Bioethanol
fridge
Bioethanol
cookstove
Flexi fuel
generator
Bioethanol
lantern
Flexi fuel
motorbike
Bioethanol
truck
Eg.
BIOETHANO
L
A One-Stop Fuel
Flexi fuel
plane
Flexi fuel car
46

47. What is Biodiesel?
• Alternative fuel for diesel engines
• Made from vegetable oil or animal fat
• Meets health effect testing (CAA)
• Lower emissions, High flash point (>300F), Safer
• Biodegradable, Essentially non-toxic.
• Chemically, biodiesel molecules are mono-alkyl esters
produced usually from triglyceride esters
Fatty Acid
Alcohol
Glycerin
Biodie
sel
FA
Vegetable
Oil
FA
FA
FA
47
Bio diesel

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50. Biodiesel Samples
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51. 51
Transesterification
While actually a multi-step process, the overall reaction
looks like this:
CH2OOR1
|
catalyst
□
CH2OH
|
CHOOR2
|
+ 3CH3OH ⬄ 3CH3OORx + CHOH
|
CH2OOR3 CH2OH
Triglyceride 3 Methanols Biodiesel Glycerin
R1, R2, and R3 are fatty acid alkyl groups (could be different, or the same),
and depend on the type of oil. The fatty acids involved determine the final
properties of the biodiesel (cetane number, cold flow properties, etc.)

52. Biodiesel Processing
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53. 53
Cost elements of bio-fuel use
• Vehicle costs
– Capital cost of vehicles
– Additional maintenance and servicing costs
• Fuel costs
– Base cost of fuel
– Fuel consumption and mileage
• Taxes and financial incentives

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Full life costing
• Capital cost of the vehicle, amortised over its life
• Fuel cost over the life of the vehicle accounting
for fuel consumption and annual mileage
• Servicing and maintenance costs
• National and local incentives such as vehicle tax
reductions, congestion charge reductions and
parking benefits

55. 55
Summary of use economics
Cost effectiveness of bio-fuel use depends on:
– vehicle costs and how these are amortised over the life
of the vehicle;
– service and maintenance costs;
– fuel costs and fuel consumption for the vehicle;
– vehicle mileages;
– national and local taxes and incentives
These factors will vary from use to use, and between
countries, regions and even cities.

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57. Biomass Applications
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59. 59
• High cycle efficiency (especially if used in cogeneration plants)
• Very high turbine efficiency (up to 90%)
• Low mechanical stress of the turbine, due to low peripheral speed
• Low RPM of the turbine allowing the direct drive of the electric generator
without reduction gear
• No erosion of the turbine blades, due to the absence of the moisture in the
vapour nozzles
• Very long operational life of the machine due to the characteristics of the
working fluid, that unlike steam is non eroding and non corroding for
valve seats tubing and turbine blades
• No water treatment system is necessary
• There are also other advantages, such as simple start-stop procedures,
quiet operation, minimum maintenance requirements and good partial
load performance.

60. Fundamentals of Solar Photo Voltaic Conversion
• Photovoltaic (PV) systems convert
energy directly into electricity.
• Commonly known as “solar cells.”
light
• The simplest systems power
calculators we use every
the small
day. More
complicated systems will provide a large
portion of the electricity in the near future.
• PV represents one of the most promising
means of maintaining our energy intensive
standard of living while not contributing to
global warming and pollution.
60

61. Typical Schematic of SEGS plants
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62. 62

63. Solar Cells
⚫ Systems can be passive or
active
⚫ Passive systems only
found in warmer climates,
as they are prone to
freezing
⚫ Active: Roof-top
collectors heat glycol
which then passes
through a heat exchanger
in the storage tank to heat
water
⚫ Electric pump can be run
on solar PV
63

64. Solar PV Power Generation
64
Solar Thermal Solar Photovoltaic (PV)
Water heating and cooking Electricity production

65. Solar Thermal Energy
Cooking Water Heating
65

66. Solar Water Heating
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67. Solar Water Heating
⚫ Solar water heating is
the most efficient and
economical use of solar
energy
⚫ Residential systems
start at $2500 and
typically cost
$3500-$4500 installed
⚫ Savings of $30-$75 per
month, lasting 20 years
⚫ Tax credits and state
rebates available
67

68. How Does it Work?
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69. 69

70. How a Power Tower Works
70

71. Benefits of Solar Cooking
⚫ Consumes no fuels/wood
◦ No loss of trees & habitat
◦ Trees sequester carbon
⚫ Generates no air pollution
⚫ Generates no greenhouse
gases
⚫ Produces no smoke
◦ Cooking smoke kills over 1.6
million people each year,
mostly women & children,
according to a recent report
⚫ Eliminates fire dangers
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72. More Benefits of Solar
Cooking
⚫ Eliminates work
◦ No daily search for
firewood
● 2 Billion people rely on
wood for cooking fuel!
◦ No risks to women and
children
◦ Frees time for other
activities
◦ No need to stir food
◦ Helps to liberate women
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73. More Benefits of Solar
Cooking
• Cooks foods slowly and
thoroughly
• Preserves nutrients
• Foods will not burn
• Pots are easy to clean;
less clean water is needed
• Use for canning
vegetables
• Use for dried fruit
• Kill insects in dry grains
73

74. Solar C
How Long Do
ooking
es it Take?
• Vegetables: 1.5 hrs
• Rice/wheat: 1.5-2 hrs
• Beans: 2-3 hrs
• Meats: 1-3 hrs
• Bread: 1-1.5 hrs
74

75. Solar PV Applications
⚫ Photovoltaic (PV) systems convert light
energy directly into electricity.
⚫ Commonly known as “solar cells.”
⚫ The simplest systems power the small
calculators we use every day. More
complicated systems will provide a large
portion of the electricity in the near
future.
⚫ PV represents one of the most promising
means of maintaining our energy intensive
standard of living while not contributing to
global warming and pollution.
75

76. How Does it Work?
⚫ Sunlight is composed of photons, or bundles of
radiant energy. When photons strike a PV cell, they
may be reflected or absorbed (transmitted through
the cell). Only the absorbed photons generate
electricity. When the photons are absorbed, the
energy of the photons is transferred to electrons in
the atoms of the solar cell.
76

77. Best Place For Solar Panels?
⚫ South Facing roof,
adequate space
⚫ No shading (time of year,
future tree growth)
⚫ Roof structure, condition
77

78. Solar Concentrators
⚫ These 20-kW Solar
Systems dishes dwarf
visitors in Alice Springs,
Australia.
⚫ The concentrators use an
array of mirrors to focus
sunlight onto
high-efficiency solar cells.
⚫ Four supports hold the
cells in front of the
mirrors
⚫ The supports also supply
cooling water and
electrical connections
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• Ad
A
van
d
ta
v
ge
a
sntages and Disadvantages
• All chemical and radioactive polluting byproducts of the
thermonuclear reactions remain behind on the sun,
while only pure radiant energy reaches the Earth.
• Energy reaching the earth is incredible. By one
calculation, 30 days of sunshine striking the Earth have
the energy equivalent of the total of all the planet’s
fossil fuels, both used and unused!
• Disadvantages
• Sun does not shine consistently.
• Solar energy is a diffuse source. To harness it, we must
concentrate it into an amount and form that we can use,
such as heat and electricity.
• Addressed by approaching the problem through:
1) collection, 2) conversion, 3) storage.