Energy and the Environment

Question 1

The nature, form and measurement of energy

Answer 1

Energy:
Energy is one of the most fundamental and critical concepts in both the natural and anthropogenic environments. Plants and animals require energy for biotic (biological) processes, such as the movement of nutrients, photosynthesis and respiration.

During photosynthesis, plants use light energy from the sin and create chemical energy in the form of sugars, which they use for respiration. Sugars are also converted to more complex carbohydrates, proteins and fats that animals, including humans, use for energy, economic and social purposes.

Advances in technology such as the car and industrial processes all hinge of people’s ability to exploit and uses various forms of energy. Electricity is one of the most important forms of energy and is used to power many devices, such as computers, televisions and cookers. Energy from burning coal, oil and gas if often used to generate electricity. Being able to generate electricity reliably, cheaply and cleanly is very important to the economies of Caribbean nations.

Question 2

Forms of Energy

Answer 2

The simplest definition of energy is ‘the ability to do work’. Work is the application of force through a distance, and power is the rate of flow of energy, or the rate at which work is done.

This energy may be in different forms- chemical energy comes from the food we consume. The food we consume is digested and energy is released from glucose using oxygen during respiration in cells. When this happens in muscle cells it allows us to move our muscles to walk, run or even lift something off a table.

Question 3

Types of Energy

Answer 3

Energy exists in many different forms- in either the kinetic or the potential state. In everyday life we utilise various forms of energy; for example, as food and as fuel for cars, buses and airplanes, in industry, tourism and other commercial activities. The forms of energy which we will address in this module include electricity, heat, light, chemical; biomass- energy from plants; fossil fuels - coal, oil and natural gas; solar energy; wind energy; hydropower; geothermal energy; energy from the ocean- wave, tidal and ocean thermal energy conversion (OTEC) and nuclear energy.

Question 4

Conversion of Energy and Efficiency & Energy conversion in the food chain

Answer 4

Conversion of Energy and Efficiency:
Energy can be transformed or converted from one form to another, for example from electrical energy to light energy when turning on a light switch. The more efficient the conversion, the more energy is utilised for useful activity than is wasted.

Question 5

Renewable and Non-Renewable Energy

Answer 5

Renewable Energy:
Renewable energy is generally defined as energy that comes from resources that can be replenished on a human time-scale. They often derive their power from the sun either directly or indirectly.

Non-Renewable Energy:
A non-renewable resource, on the other hand, is a resource that does not renew itself at a sufficient rate for sustainable economic extraction in meaningful human timeframes.

Question 6

Fossil Fuels

Answer 6

Fossil Fuel Reserves:
The three main forms of fossil fuel are oil, natural gas and coal. They were formed many hundreds of millions of years ago during the Carboniferous Period. Carbon is the basic element in coal and other fossil fuels. Oil and gas are formed from tiny aquatic plants and animals, which form a thick layer of sediment in anaerobic environments, and are often found under the ocean floor. Coal is formed on land from trees and plants in an anaerobic environment. Peat forms first, and then the weight of layers of deposited sand and rock convert it into the harder form of coal.

The Caribbean states have few reserves of fossil fuels and are net importers, apart from Trinidad and Tobago. Trinidad and Tobago have reserves of oil and gas. Recently their production of crude oil has declined, but they are now one of the largest exporters of liquid natural gas in the world.

Extraction:
The oil and natural gas is extracted from underground and under the ocean floor. A hole 12cm to 1 metre in diameter is drilled into the earth. The holes called perforations are made in the well wall that passes through the production zone. The holes are reinforced with steel or concrete to make wells. Small holes called perforations are made in the well wall that passes through the production zone. These holes provide a path for the oil to flow from the surrounding rocks into the well. In many wells, the natural pressure of the subsurface reservoir is high enough for the oil or gas to flow to the surface, where it is then prepared for transport.

Question 7

Refining, transportation and storage

Answer 7

When petroleum is refined, it is transformed from crude oil into useful products. These products fall into four categories: light distillates, middle distillates, heavy distillates and others. The products include liquified petroleum gas (LPG), gasoline, kerosene, dieseline, specialty fuels such as avgas, or other by-products such as fertilisers, paints, etc. Petroleum refineries are large industrial complexes that process hundreds of thousands of barrels of crude oil per day.

After refining, fuels, oils and natural gas may be transported through a huge network of pipelines to bring natural gas from fields so that it can be distributed to industries, homes, hotels and other facilities.

Question 8

Fossil Fuel use in the Caribbean Region

Answer 8

The Caribbean region relies on imported fossil fuels for more than 95 percent of its energy use. The exception is Trinidad and Tobago, which has reserves of fossil fuels. Power plants to produce electricity in the region are almost exclusively fuel-powered, running on gas, heavy fuel oil or light fuel oil. Electricity prices in the region are among the highest in the world, averaging US $0.35/kWh for domestic use. Transport by car, bus, boat and other vehicles is also dependent on oil.

Question 9

Nuclear Energy

Answer 9

Nuclear power refers to energy derived from either of two processes nuclear fusion or nuclear fission.

Nuclear Fusion:
Nuclear fusion is the process that takes place in the sun. Two atoms fuse together under extremely high temperatures and pressures to form a single atom. The process releases huge amounts of energy, making it attractive as a source of energy. However, it is an extremely difficult and challenging process to carry out and at the moment requires more energy than is released. Research is taking place to overcome this hurdle.

Nuclear Fission:
Nuclear fission, on the other hand, is used for the production of electricity. The nucleus of an atom, usually uranium, is bombarded, and the nucleus splits apart. During this process a tremendous amount of energy is released, which can ne harnessed to create electricity. The energy also released, which can be harnessed to create electricity. The energy also released can be utilised for destructive purposes, such as nuclear bombs, which means that this technology needs to be closely monitored.

Question 10

Nuclear Power Plant

Answer 10

A nuclear power plant uses uranium as fuel. The uranium i processed into pellets that are loaded into very long rods that are put in the power plant’s reactor. These control rods are made of chemical elements, such as boron, silver, indium or cadmium, which can absorb many neutrons without undergoing fission themselves. They are used in nuclear reactors to control the rate of fission themselves. They are used in nuclear reactors to control the rate of fission or uranium and plutonium, so that it does not proceed at such a rapid rate that an explosion would occur.

The chain reaction gives off some radioactive material as well as heat energy. This heat energy is used to boil water located in the core of the reactor. This water from the core is sent to another section of the plant, where, in the heat exchanger, it heats another set of pipes filled with water to make steam. The steam in this second set of pipes turns a turbine to generate electricity.

Question 11

The Nuclear Fuel Cycle

Answer 11

The nuclear fuel cycle is a series of industrial processes which involve the production of electricity from uranium in nuclear power reactors. There are four main stages in the cycle:
1. Mining and milling uranium
2. Refining
3. Conversion, enrichment and fuel fabrication
4. Reprocessing of spent fuel

The first three steps, make up the ‘front end’ of the nuclear fuel cycle. Fuel removed from a reactor after it has reached the end of its useful life, may undergo a further series of steps including temporary storage, reprocessing, and recycling before wastes are disposed. Collectively these steps are known as the ‘back end’ of the fuel cycle.

Question 12

Solar Energy

Answer 12

Solar energy is the radiant heat and light energy that may be harnessed from the sun using a range of technologies, including solar photovoltaics, solar thermal electricity, solar architecture and artificial photosynthesis. Energy can be derived either directly from the sun- using active or passive sources- or indirectly through other sources of energy, which derive their origin from the sun. Examples include wind, tides and biofuels.

Passive Solar Energy:
A passive solar system absorbs and stores heat from the sun directly to the structure of the building, including the walls and windows. Passive systems therefore do not involve the use of mechanical devices or the systems therefore do not involve the use of mechanical devices or the use of conventional energy sources. Classic examples of basic paive solar structures are greenhouses- as the sun’s rays pass through the glass windows, the interior absorbs and retains the heat. Energy-efficient windows, sunspaces, and walls constructed of brick, stone or other materials that retain heat, may be used. Water in storage containers can be heated up with solar energy, and used as hot water. In the Caribbean, passive solar energy is used in agriculture and botanical gardens, in nurseries and ex-situ (off site) breeding programmes

Question 13

Solar cookers and furnaces

Answer 13

A solar furnace uses energy from the sun to produce high temperatures, usually for industrial purposes. Mirrors concentrate light energy onto a focal point. Depending on the structure and the design of the furnace, the temperature at the focal point can reach 3,500 degrees Celsius.

Solar cookers tend to be used in homes to heat, cook or pasteurise food or drink. They are relatively cheap, low-tech devices, and are used in remote areas, to help reduce fuel costs for people on low incomes, and also to reduce air pollution, deforestation and desertification.

Question 14

Active Solar Energy

Answer 14

Active solar systems use devices to collect, store and convert solar energy for later use. Small systems are used to provide electricity for heating and cooling systems in homes and other buildings, while large systems can produce power for entire communities.

Active solar collectors contain either air or liquid as a conductor. Those that use air referred to as ‘air collectors’, while liquid-based types are called ‘hydronic collectors’

Question 15

Photovoltaic Cells and their advantages and disadvantages

Answer 15

Photovoltaic cells are flat- plate PV panels that are usually mounted and stationary, although some are designed to track the sun throughout the course of the day. Photovoltaics generate electric power by using solar cells to convert energy from the sun into a flow of electrons. Photons of light excite electrons into a higher state of energy and can carry charge. Solar cells therefore produce direct current electricity from sunlight, which can be used to power equipment. The direct current (DC) is changed to alternating current (AC) for the grid by an ‘inverter’. Photovoltaics are also useful for areas where it is difficult or expensive to lay down power lines.

Advantages:
- works on cloudy days
- fairly high net energy yield
- quick installation

Disadvantages:
- need access to the sun
- low efficiency
- needs electricity storage system for backup

Question 16

Biofuels

Answer 16

Biomass is the term used for plant and animal wastes that can be converted into solid, gaseous or liquid fuels. The energy derived from biomass may be used to produce electricity heat, compost or fuels. Biomass is an indirect form of solar energy because it consists of combustible organic compounds by photosynthesis

Advantages:
- large potential in the Caribbean, from organic waste derived from plant and animal sources
- moderate costs

Disadvantages:
- non-renewable if harvested unsustainably
- loss of coastal vegetation, such as mangrove, to produce charcoal

Question 17

Biogas

Answer 17

Biogas is formed when plant and animal materials, such as manure, sewage, municipal waste, green waste, plant material and crops are broken down without air by microorganisms during anaerobic digestion. Biogas is rich in methane (CH4), with some carbon dioxide (CO2) and small amounts of hydrogen sulphide (H2S). The undigested material left over, called digestate, is rich in plant nutrients and can be used as a fertiliser and soil conditioner.

For countries that use landfills to dispose of waste, as do most Caribbean states, the collection of methane and other landfill gases may be a prudent alternative. However, because both methane and carbon dioxide are greenhouse gases, the management of these wastes, especially from landfill sites, should be strictly regulated.

Advantages:
- some overall reduction in carbon emissions
- burns cleanly, no particulates
- can be made from natural gas, agricultural wastes, sewage, sludge and garbage

Disadvantages:
- may compete with growing food on cropland
- corrodes metal- rubber and plastic

Question 18

Biofuels in the Caribbean

Answer 18

An example of the use of biofuels in the Caribbean region is in Guyana, where the Institute of Applied Science and Technology (IAST) has been producing biodiesel on a commercial basis since 2006. The institute has designed and constructed a unique pilot plan for the production of quality B100 biodiesel using a variety of used vegetable and animal-derived oils available in Guyana. Many of the institute’s vehicles have been adapted to run on this biofuel.

Question 19

Wind Energy

Answer 19

What is Wind Energy?
Wind power, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emission during operation. Wind power uses the kinetic energy of wind, which can be changed into a useful form of energy, such as mechanical energy by windmills, and electric energy by wind turbines. Wind pumps can be used for pumping water or drainage.

LArge wind farms consist of hundreds of individual wind turbine, which are connected to the electric power transmission network. These structures may be located on land. They are an inexpensive source of electricity, competitive with or in many places cheaper than fossil fuels, but cause visual and noise pollution, so may affect tourism. Offshore wind farms are located in the sea and are steadier and stronger than those on land. They have less visual impact, but construction and maintenance costs are considerably higher.

Advantages:
- wind energy has a high efficiency rate
- wind energy has moderate to high net energy
- moderate capital cost

Disadvantages:
- to be efficient, steady winds are needed
- backup systems needed when winds are light
- visual pollution can discourage tourism

Question 20

Wind energy Advantages and Disadvantages

Answer 20

Advantages:
- wind energy has a high efficiency rate
- wind energy has moderate to high net energy
- moderate capital cost

Disadvantages:
- to be efficient, steady winds are needed
- backup systems needed when winds are light
- visual pollution can discourage tourism

Question 21

Hydropower

Answer 21

What is Hydroelectric Power?
Hydropower or hydroelectric power harnesses the kinetic energy of flowing water to make electricity. Water flows from dams and reservoirs. Unlike other forms of renewable energy, hydropower produces a significant percentage of the world’s primary energy.

Features of Hydroelectric Power:
The most likely widely used approach in hydropower systems is to create a reservoir by building a high dam across a river. The water in the dam flows through the intake and into a pipe called a penstock. The flow of water may be controlled depending on the demand of electricity, and smaller and lower dams may also be combined into the design. The pressure of the water into the penstock pushes against the blades of a turbine, causing them to turn. The turbine then spins a generator to produce electricity, which is then disturbed through power lines to supply the power grid.

Advantages:
- hydropower produces moderate to high net energy, and has a high efficiency rate, since plants can be ramped up and down quickly to adapt to changing energy demands.
- once operational, the cost of electricity is low
- Lower carbon dioxide emissions than fossil fuels.

Disadvantages:
- costs of construction and initial facilities can be expensive, especially as most schemes are in remote uninhabited mountainous areas, e.g. the Amalia Falls in Guyana.
- There is a danger of flooding from the reservoir if the dam fails.
- high carbon dioxide emissions from biomass decay in shallow tropical reservoirs.

Question 22

Pumped Storage Reservoirs

Answer 22

Pumped storage reservoir can provide ready electricity during periods of high demand. When there is a sudden demand, water in a top reservoir is released to the turbines and engines below. The water collects in the bottom reservoir, and can be pumped back to the top when the demand for power is low. Although the losses of the pumping process make the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest. Pumped storage power systems are about 75 percent efficient, and have high installation costs, but their low running costs and ability to reduce the required electrical base load can save both fuel and total electrical costs.

Question 23

Geothermal Energy

Answer 23

What is Geothermal Energy?
Geothermal energy uses the heat in the Earth’s core to generate electricity. The centre of the Earth is approximately 6000 degrees Celsius, and even a few kilometres below the surface, the temperature can be over 250 degrees celsius. Geothermal energy has been used for thousands of years in boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating- opening a potential for widespread exploitation.

Features of Geothermal Energy:
hot rocks underground heat water to produce steam in the process. This steam may be used to drive turbines and electric generators. The energy is tapped via a series of pipes, one of which pumps cold water down into the Earth’s Mantle, ad another which pumps up the heated water and steam. Geothermal energy has been identified by the US Environmental Protection Agency (EPA) as the most energy-efficient, cost-efficient source of energy, and an environmentally clean way to produce energy.

Question 24

Advantages and disadvantages of Geothermal Energy

Answer 24

Advantages:
- Has a high efficiency rate
- Moderate net energy
- Once operational, the cost of electricity is low

Disadvantages:
- Costs can be high, except at the most concentrated and accessible sources- therefore not sutiable for all Caribbean states, especially those that are not on active tectonic plates
- Noise and hydrogen sulphide odours

Question 25

Geothermal Energy in the Caribbean

Answer 25

Geothermal energy is not suited for most of the Caribbean, but it is a viable alternative for those islands that are largely volcanic in origin, and which still have some active volcanic features.

Legislation- is often needed to extract geothermal energy because the process touches on legal issues including questions of ownership and allocation of resources and the extent to which geothermal energy issues have been recognised in existing planning and environmental laws.

Question 26

Ocean Thermal Energy Conversion (OTEC)

Answer 26

Ocean thermal energy conversion is a renewable energy technology which harnesses the solar energy absorbed by seas and oceans to generate electric power. The basis of the technology is the temperature difference between the cooler deep water and the warmer shallow or surface ocean waters.

Advantages:
- OTEC technology uses the solar energy stored in the world’s oceans, and can therefore operate virtually continuously.
- OTEC is a clean, renewable and abundant energy source, which produces few or no carbon emissions.
- Once operational, the cost of electricity is low

Disadvantages:
- The startup cost is extremely high
- OTEC plants must be located where a difference of 22 degrees celsius occurs year-round

Question 27

Wave and Tidal Energy

Answer 27

Wave Energy:
Wave power is an indirect form of solar power, because it is the sun that generates air currents which, as they pass over the sea, generate and transfer energy to the waves.

Advantages:
- can produce moderate to high net energy
- no carbon dioxide emissions
- reduced imports of fossil fuels

Disadvantages:
- requires a suitable site, where waves are consistently strong to ensure a consistent energy source
- some designs are noisy

Tidal Energy:
Tides, caused by the gravitational pull on the Earth by the moon, occurs twice daily on a predictable basis. Harnessing tidal movements could provide a great deal of energy, but while supplies are potentially reliable and plentiful, converting it into useful electrical power is often challenging.

Advantages:
- tidal energy has a moderate efficiency rate
- high net energy
- once operational the cost of electricity is low

Disadvantages:
-Mechanical fluids, such as lubricants, can leak out, which may be harmful to the marine life nearby, but with proper maintenance this threat can be maintained.

Question 28

Fuel Cells

Answer 28

Key Features of the Fuel Cell:
A fuel cell converts the chemicals hydrogen and oxygen into water, producing electricity in the process. Hydrogen is the most common fuel used in a fuel cell, but other compounds that contain hydrogen bonds, such as hydrocarbons or alcohols, may also be used.

Limitations and reliability of supply:
Despite being a potential alternative to fossil fuels, there are some challenges to the use of fuel cells as a source of energy. The first challenge is finding a reliable and steady source of hydrogen, because unlike oxygen, hydrogen is not readily available. Storing hydrogen to operate a vehicle can be difficult due to the fact that a huge tank would be needed.

Advantages:
- hydrogen can be produced from plentiful water
- high efficiency
- low environmental impact

Disadvantages:
- hydrogen is not found as a pure element in nature
- energy is needed to produce fuel
- short driving range for current fuel-cell cars

Question 29

Limitations on energy sources: Reliability of supply; technological and geographical factors

Answer 29

Reliability of supply:
The reliability of a source of energy. Factors that affect the reliability of an energy source are availability and a consistent electrical output. The electrical output needs to be constant and cater for the requirements at peak demand, so that electricity can be provided to consumers without being considered unreliable.

Technological Limitations:
Some of the key factors affecting many renewable energy sources are the technological limitations to their widespread and efficient use. Most of the challenges relate to overcoming the diffuse and intermittent nature of renewable energy, which affects its reliability as a viable energy source. The challenge is that the technology enabling renewable energy generation is not as developed as that for non-renewables such as fossil fuels and nuclear energy.

Geographic Restrictions:
The topography, as well as geographical factors such as urbanisation and the location of protected areas, can influence location of power sources, as well as the construction of generating plants and transmission devices, such as electricity poles and transformers.

Question 30

Economic, political and social factors influencing energy use

Answer 30

Economic Factors:
A country’s economic development model may serve as a catalyst or inhibitor to its energy exploitation and use. For example, if the country’s policies promote extractive industries, the export of primary products and foreign investment can affect the type and extent of energy use. This is the case in the Bahamas, where the government has entered a power-purchase agreement with a US investor to establish a fully commercial OTEC plant.

Political factors:
Government policies such as foreign direct investment, privatisation, nationalisation, and the environment and sustainable development policies, can affect the use and exploitation of energy resources. Trinidad and Tobago for example, benefited from investment by many established oil companies in the development of their oil and gas industry.

Social Facotors:
The population growth and needs of a country directly affect its energy use, since energy is required for most aspects of modern life. Conversely, the per capita income of the populace is an important consideration, which governments and utility companies need to take into account, since this will affect the level of rates and tariffs.

Question 31

The Generation and Distribution of Electricity

Answer 31

Generation of Electrical:
During the generation of electricity, primary energy from fossil fuels, nuclear energy or renewable sources of energy are converted into electrical energy. The British scientist Michael Faraday discovered the technology and processes through which electricity is generated during the 1820s and early 1830s.

Transmission of Electricity:
Generating electrcicity as efficiently as possible is important. When electricity has been generated, it is transmitted to electrical sub-stations located near demand centers. Large generators in power stations spin, and produce electricity with a voltage of about 25,000 volts. The electricity goes through a transformer at the power plant to boost the voltage to 400kV. This is because electricity can be transferred more effectively at high voltages.

Distribution of electricity:
In each area where electricity is to be distributed, a small transformer is mounted on a pole or similar structure, and this converts the power to the lower level of voltage which can be utilised at the point of distribution. For most of the urban areas in the Caribbean this is 110 volts, while in Grenada it is 220 volts.

Question 32

Factors Affecting electricity generating capacity

Answer 32

Generation rates and demand patterns:
Countries with very large populations or heavy industrialisation require considerable amounts of energy and so will have greater electricity consumption patterns. For example, Trinidad and Tobago and Jamaica- which have larger populations and are more industrialised than the average Caribbean state- will have greater demand for energy. The demand pattern shoes how much energy is required and when.

Energy Storage and Stock Piling Capability:
Energy storage and stockpiling is a prudent strategy to ensure that there is a seamless supply of energy, to limit the possibility of interruptions, and to ensure and increase the efficiency of pipelines through better load factors.
Therefore for energy sustainability and security, a country will maintain a supply of fuel in storage, and even stockpile depending on consumption requirements and generation patterns.

Diversity of Energy Sources:
More than 90 percent of the power supply in the Caribbean comes from imported fossil fuels, which makes the region one of the most import- dependent in the world where petroleum is concerned. However, diversifying the sources of energy can reduce the pressure on governments to buy in fossil fuels from external sources, and achieve better energy security. Diversification of energy sources depends on the existence of viable quantities of alternative energy sources, the ability to invest in them, and policies that provide a facilitating environment to make use of these energy sources.

Government Policies:
In an effort to reduce the economic costs associated with the acquisition of fuel, governments may introduce policies aimed at acquiring fuels at better concessionary rates, energy conservation or investment on renewable energy. The overarching goal of these policies is to provide energy security for the country, especially for states that spend a large proportion of their gross domestic product (GDP) on fuel.

Question 33

Energy Conservation and Efficiency

Answer 33

Energy Conservation:
Energy conservation refers to strategies aimed at reducing the energy used.

Energy Efficiency:
Energy efficiency involves using less energy for a constant activity.

Approaches to Energy Conservation:
Approaches aimed at energy conservation are diverse and vary in the transportation, domestic and industrial sectors. A primary method to improve energy conservation in buildings is to use an energy audit, which is an inspection and analysis of energy use and flows for energy conservation in a building, process or system.

Transport:
In the transportation sector energy conservation measures unclude reducing the amount of times you drive, car-pooling and using public transportation. While there has been an increase in the use of fossil fuels in the transportation sector in the Caribbean, there are measures that states can use to promote energy conservation. For example, policies which encourage walking and bicycling can greatly reduce the energy consumed for transportation,

Buildings:
Advanced real-time energy metering can allow users, business and residential, to see graphically the impact their energy use can have in their workplace or home. People are more likely to save energy because they are aware of their actions.

Economic Incentives:
Many countries in Europe and some areas of North America have introduced energy or carbon taxes. These motivate energy users to reduce their consumption, or encourage the use of renewable energy alternatives to reduce the environmental consequences arising from energy production.

Question 34

Cogeneration and combined Cycle Generation

Answer 34

Cogeneration:
Cogeneration is also referred to as combined heat and power (CHP). This is the simultaneous production, and subsequent use, of the heat as well as the electricity emitted from thermal power plants. Facilities which can be serviced by a cogeneration plant include domestic buildings, industrial facilities and- for larger applications- towns and cities. The heat demand of the facilities to be supplied needs to be known and factored into the design to optimise the use of the electrical and thermal energy resulting from the process. If designed to meet optimal conversion and utilisation, the efficiency of a cogeneration plant can reach 90 per cent or more.

Combined Cycle Generation:
The principle underpinning the concept of a combined cycle is based on the combination of two or more thermodynamic cycles to improve the overall efficiency of a generation process, while at the same time reducing the costs of fuel. This combined cycle can be achieved utilising the process involved in the operation of traditional power plants. In the traditional power plant, the potential energy stored in the fuel is converted into electric power by a turbine, and then transformed into electric power by a generator.

Question 35

Alternative Energy Sources

Answer 35

Use of Alternative Energy Sources:
Alternative energy refers to any energy that does not involve the use of fossil fuels. These sources include biodiesel and other biomass sources such as bioalcohol, and chemically stored electricity such as fuel cells.

Use of Renewable Energy:
Th aim of achieving 100% renewable energy use, to produce electricity and for transport, is seen as desirable not only to combat global warming but also to address the chronic dependency of countries, like those in the Caribbean, on fossil fuels. By using energy sources that are indigenous to the region or specific islands, Caribbean states can spend less on fuels, produce less pollution and avoid exposure to the volatility of market prices.

Using Alternative Technologies:
Another strategy to increase energy efficiency is to use technologies which enable the more efficient use of energy, thus maximising the per capita use of fossil fuels. Example, using more energy efficient appliances.

Sustainable Lifestyles:
A sustainable lifestyle adopts measures that will reduce an individual’s or society’s use of energy and other natural resources. Sustainable living practices can range from taking simple initiatives, such as turning off the light when leaving the room, the water while brushing teeth to walking or car-pooling or taking mass transport instead of driving everyday.

Question 36

Impacts of Extracting and Using Energy

Answer 36

The environmental impact of the extraction and use of energy varies depending on the type of energy and the phase of the process- in other words whether it is during extraction, transportation or generation of the energy.

Fossil Fuels and Natural Gas:
When fossil fuels are burned they emit CO2 which is the main contributor to anthropogenic (man made) global warming. Carbon monoxide, nitrogen and sulhpur oxides are produced at the same time, leading to air pollution, including smog and acid rain.

Nuclear Energy:
Nuclear power does not contribute to climate change. However, it does produce at least four different types of waste that may harm the environment:
- spent nuclear fuel at the reactor site
- tailings and waste rock at uranium mines and mills
- releases of small amounts of radioactive isotopes during reactor operation
- releases of large quantities of dangerous radioactive materials during accidents (Chernobyl) or as a consequence of natural disasters (Fukushima).

Solar:
Solar power has little impact on the environment, however, there may be habitat destruction or fragmentation to sites with large areas of photovoltaic cells. These also cause visual pollution in that they reduce the aesthetic quality of the environment.

Hydropower:
Dead vegetation in the dam after flooding or due to eutrophication will emit methane and other greenhouse gases when bacteria decompose it. Increased sedimentation near the reservoir can affect turbidity, etc.

Question 37

Impacts of Extracting and Using Energy

Answer 37

Biofuels:
There are concerns about removing plants and if they are not replaced the effect on carbon sequestration. Biofuels will still pollute the atmosphere when burned, though to a lesser extent than fossil fuels and natural gas, and they also emit carbonyls.

Geothermal:
Geothermal systems can emit hydrogen sulphide, carbon dioxide, ammonia, methane and boron. They can affect both water quality and consumption, as the hot water pumped from underground reservoirs often contains high levels of sulphur, salt and other minerals.

Water, Tidal and OTEC:
OTEC can release CO2 dissolved in the lower layer of water when it is brought up to the surface because the pressure of the seawater is reduced.

Wave and tidal systems produce noise pollution from turbines. The barrages can also disrupt the migratory paths of fish and cetaceans, such as whales, porpoises and dolphins.

Wind:
Wind turbines can disturb the landscape and be noisy, therefore causing visual and noise pollution. They may affect migratory birds, who may crash into the turbine blades, towers or transmission lines. Wind farms may cause habitat fragmentation and can alter the microclimate of the areas immediately around them.

Question 38

Socioeconomic Impacts of Energy

Answer 38

The effects of the sourcing and use of both renewable and non-renewable energy can impact directly on humans, our society and economies. Small-scale decentralised energy projects, which often generate renewable energy, tend to be community based.

Fossil Fuels:
The particulate emissions from power plants and the smog formed can cause respiratory diseases. Particulate emissions and acid rain can also affect buildings and plant and animal life. Oil spills can cause economic hardship to coastal communities by affecting fishing and tourism, as well as the ecosystem. Coal mining and oil refineries can affect the areas where people can live and utilise land.

Nuclear Energy:
During their operation, nuclear plants can release toxic pollutants and gases, such as carbon-14, iodine-131, krypton and xenon into the atmosphere, which over time can be carcinogenic to workers and the surrounding population. In addition, as evidenced by the accidents at Chernobyl (1986) and Fukushima (2011), the fallout during nuclear accidents can be catastrophic, not only to the people in the immediate area, but also to distant communities as the plume spreads.

Solar:
Solar power has no known health risks but in an effort to site large-scale solar projects close to the areas where power is required, land which may be valuable for housing or growing crops may need to be utilised.

Hydropower:
In tropical areas, slow-moving reservoirs may be the breeding ground for mosquitos which can spread malaria and dengue fever, and also snails, which can spread malaria and dengue fever, and also snails, which are vectors for schistosomiases. Dam construction may n=involve large-scale resettlement of people.

Question 39

Socioeconomic Impacts of Energy Cont’d

Answer 39

Biomass:
Although biomass is renewable it still gives off particulates, carbonyls and carbon dioxide, which can cause respiratory diseases. Growing biomass for biofuels is economically rewarding for farmers, but this is a problem because it means prime agricultural land is used to grow biomass or oil rich crops for biofuels rather than food.

Geothermal:
The health risks associated with geothermal energy are minimal, provided that gases are not vented into the atmosphere and that water contaminated with heavy metals and toxic chemicals is not allowed into the environment. In an effort to site geothermal generating systems close to the areas where power is required, land which may be valuable for housing or arable purchases may need to be utilised.

Wave, tidal and OTEC:
Barrages can disrupt the migratory path of fish and cetaceans, such as whales. This can have very negative effects on fishermen and coastal communities that depend on sea fishing.

Wind:
Noise pollution from the wind turbines can be very stressful for people living close to wind farms. In an effect to site wind farms close to the areas where power is required, land which may be valuable for housing or farming may be used.

Question 40

Cost Associated with Energy

Answer 40

Political Cost:
Political policies affect the cost of energy in a country. For example, a state may subsidise the cost of fuel in order to make it easier for consumers to buy. Secondly, the policies a state embarks on can influence the kind of energy a state may invest in. and whether or not renewable energy as a source is encouraged.

Economic Costs:
Economic issues will affect the cost of energy in a country. Consumers as well as industries will choose the cheapest source of energy available, because that cost will directly affect the cost of their products and lifestyle.

Social Costs:
The use of energy often has by-produce and side effects associated with it. For example, nuclear energy has the threat of radioactive poisoning while fossil fuels can emit high levels of particulate matter when they are burned and emit greenhouse gases. Particulate matter can have far-ranging effects on humans, including respiratory diseases and skin ailments. If these diseases affect the working population, this will have a direct impact on the productivity of the country, and consequently on its economy and social services.

Environmental Costs:
Both non-renewable and renewable energy sources have environmental costs associated with them, which need to be considered when deciding which energy source to use. Fossil fuels em9t high levels of carbon and nitrogen oxides when they are burned. This raises the levels of these gases in the atmosphere. Therefore the combustion of fossil fuels contributes to environmental pollution.

Technological Cost:
The technology required to use a form of energy effectively is a cost that also needs to be factored into energy use. Thus, the appropriateness, availability, affordability and environmental soundness of a technology are important considerations.

Question 41

Is the use of Renewable Energy in the Caribbean Region Feasible?

Answer 41

Wigton Farm, Jamaica:
Wigton Wind Darm Ltd. is a subsidiary of the Petroleum Cooperation of Jamaica. Located in Manchester, the estimated capacity of the wind farm is expected to ne 20.7MW, provided from twenty-three 900kW rated wind turbines. Wigton successfully generates and delivers electricity to the Jamaica Public Service Company Limited (JPSCo), under a Power Interchange Agreement.

Barbados’ Diverse Fuel Mix:
Barbados has made historical advances in incorporating renewable sources of energy into its energy generation. As a result, Barbados has a more diverse fuel mix than other CARICOM countries, and one of the lowest domestic electricity rates in the Caribbean region, which is estimated at 41-42 cents per kilowatt-hour.

Geothermal Energy in the Caribbean:
At present the French territory of Guadeloupe has the only geothermal plant in the Caribbean region, but Dominica, St. Kitts and Nevis and the British overseas territory of Montserrat are actively pursuing geothermal investors in development on St.Lucia.