energy management in agriculture lecture notes

Course: Energy management in Agriculture

Lecturer: Jean de Dieu IYAKAREMYE, Msc.E-mail:[email protected]

UR/College of Agriculture, Animal Sciences and Veterinary Medecine

Energy is the driver of growth Energy provides better living conditions to

its citizens Its growth has to be balanced and

sustainable energy management and energy

conservation measures are: eco-friendly, minimum pollution and carbon emission

Energy management

The fundamental goal of energy management is: produce goods, provide services with the least cost and the least environment effect

The definition of energy management is:“The judicious and effective use of energy to maximise profits (minimise costs) and enhance competitive positions”.

Energy management

Objectives: To achieve and maintain optimum energy

procurement and utilization, throughout the organization

To minimize energy costs / waste without affecting production, comfort and quality. To minimize the environmental effects.

Energy management

Energy in any form is a scarce commodity and most valuable resource

As by prediction showing that the life expectancy of world population will increase so energy could, in the future, be in short supply

Energy conservation

There are two main sources of energy. They are conventional and non conventional sources of energy.i) Conventional sources of energy :- are wood, flowing water and fossil fuels (coal, petroleum, natural gas).ii) Non conventional sources of energy :- are solar energy, windenergy, biomass energy, ocean energy (tidal energy, wave energy,ocean thermal energy), geothermal energy, nuclear energy etc. Some sources of energy are renewable like sun, wind,

flowing water, ocean, wood, biomass etc. Some sources of energy are non renewable like coal,

petroleum and natural gas.

Sources of energy

a) Fossil fuels :- are fuels formed inside the earth from theremains of plants and animals after millions of years. Thefossil fuels are coal, petroleum and natural gas. Fossilfuels are non renewable sources of energy so theyshould be conserved and used judiciously.Disadvantages of fossil fuels :-i) Burning of fossil fuels release gases and harmful particles which causes air pollution.ii) Burning of fossil fuels release acidic oxides of sulphur and nitrogen which causes acid rain which is harmful for living organisms, affects soil and water, causes damage to buildings, corrosion of metals etc.iii) Burning of fossil fuels release a large amount of carbondioxide gas which increases the temperature of the atmosphere and causes global warming (green house effect).

Conventional sources of energy

b) Thermal power plants : In thermal power plants the heat energy

produced by burning fossil fuels like coal, petroleum or natural gas is used to heat water and change it into steam which rotates the turbines of generators to produce electricity.

c) Hydro power plants : In hydro power plants water from rivers are

stored by constructing dams. The water from the dam flows down through pipes and rotates theturbines of generators to produce electricity.

Conventional source of energy

Advantages of hyropower:i) Flowing water is a renewable source of energy.ii) The electricity produced does not cause pollution.iii) The water stored in dams can also be used to control floods and for irrigation.Disadvantages of hydropower:i) The initial cost is high.ii) Large areas of land gets submerged and the decomposition of vegetation produces methane gas which is a green house gas.iii) It causes displacement of people from large areas of land.

Conventional source of energy

Thermal power plant

Hydropower generation

d) Biomass energy : The waste materials and dead parts of living

things are called biomass. Eg :- wood, animal dung, vegetable waste, agricultural waste, sewage etc. Biomass is decomposed by anaerobic microorganisms to produce biogas. Biogas is a mixture of gases containing methane, carbon dioxide, hydrogen and hydrogen sulphide.

Conventional energy sources

Biogas plant :The biogas plant has a large underground tank made of bricks and cement. The lower part is the digester and the upper part has a dome with a gas outlet. On one side of the tank above the ground is a mixing tank and on the other side is an overflow tank. Animal dung is mixed with water in the mixing tank and the slurry is sent into the digester. In the digester the slurry is decomposed by anaerobic microorganisms and after a few days biogas is produced. The gas is taken out through the gas outlet and used for heating and lighting purposes. The slurry left behind is rich in nitrogen and phosphorus and is used as manure for crops.


Biogas plant

e) Wind energy :Wind energy is used in wind mills which converts the kinetic energy of the wind into mechanical or electrical energy. The kinetic energy of wind can be used to do: mechanical work like lifting water from wells or

grinding grains in flour mills. It can also be used to rotate the turbines of

generators to produce electricity. A single wind mill produces only a small amount of

electricity. So a large number of wind mills in a large area are

coupled together to produce more electricity in wind energy farms.


Advantages :i) It is a renewable source of energy.ii) It does not cause pollution.iii) The recurring cost is less.Disadvantages :i) Wind is not available at all times.ii) It requires a large area of land.iii) A minimum wind speed of 15 km/h is required.

Conventional energy sources (wind energy)

Wind energy farm

a) Solar energy :Solar energy is the energy obtained from the sun in the form of heat and light. The heat energy is used in solar heating devices like solar cooker, solar water heater, solar furnaces etc. The light energy is used in solar cells.i) Solar cooker :The box type solar cooker has an insulated box painted black inside.It is covered by a glass plate which allows heat to enter inside but does not allow heat to escape out. It has a mirror to reflect more sunlight into the box. The food to be cooked is kept in containers inside the box It can produce a temperature of 100° to 140°.

Non conventional sources of energy

ii) Solar water heater :A solar water heater has an insulated box painted black inside with a system of copper tubes. It is covered with a glass plate which allows heat to enter inside but does not allow heat to escape out. When water flows through the copper tube it absorbs heat and becomes hot.

Solar energy

iii) Solar cells :-Solar cell is a device which converts solar energy into electrical energy. Solar cells are made from semi conductors like silicon, germanium, gallium etc. A single solar cell produces a voltage of about 0.5 to 1 V and produces about 0.7 W electricity. So several solar cells are arranged in a solar panel to

produce more electricity.Advantages :i) It uses renewable source of energy.ii) It produces electricity which does not cause pollution.iii) It can be used in remote areas where there is no power supply.

Solar energy

Disadvantages of solar cells:i) It uses a special grade of silicon which is expensive.ii) Since silver is used for connecting the cells together it is more expensive.iii) The current produced is DC and to convert it to AC increases the cost.

Solar energy

b) Energy from the sea :Energy from the sea is obtained in three different forms. They areTidal energy, Sea wave energy and Ocean thermal energy.i) Tidal energy :The periodic rise and fall of sea level due to gravitational attraction of the moon causes tides. A dam is constructed at a narrow openingbetween the land and sea. The movement of water during high tide and low tide can be used to rotate the turbines of generators to produce electricity.ii) Sea wave energy :- When strong wind blows over the sea it produces huge waves. The kinetic energy of the moving waves can be used to rotate

the turbines of generators to produce electricity.

Energy from the sea

iii) Ocean thermal energy :There is a temperature difference between the warm surface water and the cold water at the bottom of the oceans. This difference is about 20°C. The warm surface water is used to boil liquid ammonia and the vapour is used to rotate the turbines of generators to produce electricity. The cold water from the bottom is then pumped up to cool the vapour back to liquid.

Energy from the sea

The deeper regions of the earth’s crust is very hot.

This heat melts rocks and forms magma. The magma moves up and collects below at

some places called Hot spots. The underground water in contact with hot spot gets heated into steam at high pressure.

By drilling holes into hot spots the steam coming out can be used to rotate turbines of generators to produce electricity.

Geothermal energy

d) Nuclear energy :Nuclear energy is the energy is the energy released during nuclear reactions.During nuclear reactions some mass is converted into energy and so a verylarge amount of energy is produced during nuclear reactions.Nuclear reactions are of two types. They are Nuclear fission and nuclear fusion.i) Nuclear fission : is a nuclear reaction in which the nucleus of a heavy atom like uranium, plutonium, etc. splits into smaller nuclei with the release of a large amount of energy. It is used to make atom bombs and to produce electricity.In a nuclear power plant the heat energy produced by a controlled nuclear fission chain reaction is used to produce steam which rotates the turbines of generators to produce electricity.

Nuclear energy

ii) Nuclear fusion :- is a nuclear reaction in which small nuclei fuse together to form a heavier nucleus with the release of a very large amount of energy. The energy of sun is produced by the fusion of hydrogen nuclei to form helium nucleus. It is also used to make the hydrogen bomb.Advantages of nuclear energy :i) It produces a very large amount of energy per unit mass than any othersource of energy.ii) If safety measures are taken, it is more environment friendly than fossil fuels.Disadvantages of nuclear energy :i) The cost of a nuclear reactor is very high.ii) The availability of nuclear fuel is limited.iii) Nuclear reactors produce harmful nuclear wastes which is difficult to dispose.

Nuclear energy

The mobile farm power comes: from human, draught animals, power tillers, tractors and self propelled machines

The stationary power is obtained from oil engines (diesel, petrol, kerosene) and electric machines.

Farm power sources

Human Power The average power availability, in sustained

working, from a male agricultural worker is

considered as 60 watts (0.06 kW) while for a female worker it is considered as

48 watts (0.048 kW) and For child worker as 30 watts (0.03 kW)

Farm power

Draught animal power: The power available from draught animals is related to its body weightFor ex: Bullocks : 10-12% of body weight in summer

and 12-14% in winter Buffaloes : 12% of body weight in all seasons Camels : 18% of body weight up to 7 h, 26% up

to 6 h following 2 h work + 2 h rest schedule. Donkeys : 32% of body weight up to 6 h and

36% up to 4 h in two shifts.

Farm power

Mobile Power from Tractors, Power Tillers and Self-Propelled Reapers and Combines

Big range of power are available on the market depending on your land and production

Farm power

Stationary Power from Diesel Engines and Electric Motors Depending on the size of thefarm and the

purpose of use

Farm power

Energy Conservation is the deliberate practice or an attempt to save: electricity, fuel oil, mechanical power, gas or any other combustible material

Energy Conservation is to be able to put to additional use for additional productivity without spending any additional resources or money.

Energy conservation

Energy conservation is achieved when: growth of energy consumption is reduced, measured in physical terms

Energy conservation can be the result of several processes or developments( increase of productivity or technology)

Energy conservation and Energy Efficiency are separate, but related concepts.

What is energy conservation?

Energy efficiency is achieved when energy intensity in a specific product, process or area of production or consumption is reduced without effecting output, consumption or comfort levels.

Promotion of energy efficiency will contribute to energy conservation and is therefore an integral part of energy conservation promotional policies.

Energy efficiency

For example, replacing traditional light bulbs with Compact Fluorescent Lamps (CFL) (which use only 1/4th of the energy to same light output). Light Emitting Diode (LED) lamps are also used for the same purpose.

Energy efficiency

i) Minor ECOs These are simple, easy to implement, and

require less investment implementation time. These may correspond to stopping of:

- leakage points, avoiding careless waste, lapses in housekeeping- and maintenance etc.

Energy conservation opportunities

ii) Medium ECOs These are more complex, and required

additional investment and moderate implementation time.

For example, replacement of existing household appliances or any other energy source by new energy efficient ones.


iii) Major ECOs These provide significant energy saving.

They are complex and demand major investment and long implementation periods.

For example, replacement or major renovation of old buildings, machineries etc.


Energy management and conservation sequence and steps

Psycho-social (people do not like to change: social taboos and traditions)

Economic (replacements often costly).

Barrier to energy conservation

Is the key of energy conservation and management

Energy audit is defined as "The Verification, Monitoring and Analysis of use of energy including: submission of Technical Report containing recommendations for improving energy efficiency with cost benefit analysis, and an action plan to reduce energy consumption".

Energy Audit

Energy Accounting

Energy accounting simply means record of energy used in an establishment for comparison against a budget or another standard of performance.

Energy Audit

Systematic Approach To Decision Making

Energy Audit is the key to systematic approach for decision making in the areas of energy management. It attempts to balance the total energy inputs with its use and serves to identify all the energy streams in a facility. It quantities the energy usage according to its discrete functions.

Energy Audit

Effective Tool for Energy ManagementEnergy Audit is an effective tool in defining and pursuing comprehensive energy management programme. In this field also, the basic functions of management like planning, decision making, organizing and controlling, apply equally as in any other management subject.

Energy Audit

Ways of Usage of EnergyEnergy Audit will help to understand more about the ways energy and fuel are used in any establishment, and help in identifying the areas where waste can occur and where scope for improvement exists.

Energy Audit

Construction and Stream LiningThe Energy Audit would give a positive orientation to the energy cost reduction, preventive maintenance and quality control programme which are vital for production and utility activities/.

Energy Audit

Ideas and Feasible SolutionIn general, Energy Audit is the translation of conservation ideas into realities, by blending technically feasible solutions with economic and other organizational considerations within a specified time frame. In brief energy audit is an in-depth study of a facility to

determine how and where energy is being used or converted from one form to another, to identify opportunities to reduce energy usage, to evaluate the economics and technical practicability of implementing these reductions and to formulate prioritized recommendations for implementing measures to save energy.

Energy Audit

Scope of energy Audit

Model projects

Comparison of energy utilization of different crops

Energy accounting of a specific crop from tillage to harvesting.

Energy Audit in a small scale village industry

Energy accounting of a brick kiln Energy accounting of flour mill Energy Audit in ISAE Farm

Suggestive project areas

Students will be given different papers to analyze and submit the findings

Three types of papers are given

Energy requirements of different operations in agriculture

1. Explain how conventional energy sources are used in Rwandan Agriculture and give 5 examples

2. Describe Non conventional energy sources use in Rwandan Agriculture and give 5 examples

3. What are the most used energy sources in Rwandan Agriculture? Why is it so?

4. In your own words define “Energy management for Agriculture”

Homework #1

Read the Paper and understand it before answering these following questionsPaper Title: Energy Efficiency of Conventional, Organic, and Alternative Cropping Systems for Food and Fuel at a Site in the U.S. Midwest( by S I E G L I N D E S . SN A P P , A N D G . P H I L I P R O B E R T S O N ) 1. What are the objectives of this study?2. Describe the need of this study3. Discuss briefly on materials and methods used4. Compare energy efficiencies in 5 systems which are

discussed in this paper

Assignment #1

Read the Paper and understand it before answering these following questionsPaper Title: Impacts of organic farming on efficiency of energy use in Agriculture (by David Pimentel)1. Write down the main objectives of this paper2. What are the main differences in energy

requirement between conventional and organic farming?

3. What are the benefits of organic farming over conventional farming?

4. Why organic farming is preferred?

Assignment #2

Read the Paper and understand it before answering these following questionsPaper Title: Energy use pattern analyses of greenhouse vegetable production (By M. Canakci, I. Akinci)1. Describe the objectives of this study2. What is the relationship between energy input and

crop yield on different crops discussed in this paper.3. Briefly discuss materials and methods used in this

paper.4. Which plant does not require much energy for

production?

Assignment #3

THANK YOU !!!

energy management in agriculture lecture notes

Engineering