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Renewable energy sources dr Magdalena Klimczuk-Kochańska Since Thomas Edison harnessed electricity and Nikolaus A. Otto popularized the internal combustion engine, energy has received a central role in commerce and everyday life. Our current living standard could not be maintained without energy. As the energy utilization increases "energy problem" in conjunction with the underlying "environmental problem” continues to be a major topic in energy engineering, as well as in the energy and environmental policies in the world. Energy terms Energy is the amount of work a physical system is capable of performing. Energy cannot be created, consumed, or destroyed. The catch is that entropy—the amount of energy not available to perform useful work— increases every time e.g. someone moves lift a finger, because energy is dissipated into the universe as heat. Energy can also be converted or transferred into different forms. Forms of energy Kinetic energy is the energy of motion. It is possessed by any moving object. Gravitational potential energy - energy associated with the gravitational pull of the Earth (and Sun) Electrical energy - energy associated with electrical forces which hold together the atoms and molecules of all materials Incl. chemical energy; electromagnetic energy; electricity (intermediate form of electrical energy) Atomic or nuclear energy - energy bound up in the central nuclei of atoms. Forms of energy The kinetic energy of moving air molecules can be converted into rotational energy by the rotor of a wind turbine, and then converted into electrical energy by a wind turbine generator. With each conversion, part of the energy from the source is converted into heat energy. The thermal efficiency (TE) of an energy source indicates the percentage of its energy that can be used directly in the next link of the energy conversion system, rather than being converted into heat. E.g. A coal-fired power plant is about 33 % efficient, meaning that it uses 3,000 mega watts of energy stored in coal to generate 1,000 megawatts of electricity. The other 2,000 megawatts are lost as heat energy. The TE of a typical car is about 26 %. Some racing engines have a TE of 34 %. The photovoltaic cells in solar panels are 7 to 17 % efficient. Units of energy Power is the rate of energy transfer per unit of time. Power is measured in watts or horsepower. Energy is measured in joules (J) or kilowatt hours (kWh). A watt is one joule per second, so a 60-watt light bulb uses 60 joules of energy per second, converting the electric energy into light energy and heat energy. One horsepower equals 746 watts. One calorie equals 4.18 joules, the energy needed to raise the temperature of one gram of water by one degree Celsius. A British thermal unit (BTU) equals 1,055 joules, the energy needed to raise one pound of water one degree Fahrenheit. One kilowatt (kW) equals 1,000 watts and one megawatt (mW) equals one million watts. Units of energy The petajoule (PJ) is equal to one quadrillion (1015) joules. 210 PJ is equivalent to about 50 megatons of TNT. This is the amount of energy released by the Tsar Bomba - the largest nuclear bomb - Russia, 1961 https://www.youtube.com/watch?v=RNYe_UaWZ3U The zettajoule (ZJ) is equal to one sextillion (1021) joules. The human annual global energy consumption is approximately 0.5 ZJ. Energy terms Mentions of energy “production” or “generation” refer to the conversion of energy into a more usable form. Energy “loss” means that energy is dissipated as heat, or for some other reason becomes unavailable for useful work. The fundamental task of most commercial electricity production is to make turbines spin and thereby create an electrical current. Both nuclear fission and coal combustion create steam that turns turbines. The kinetic energy from wind and falling water turns turbines directly to generate electricity. You can generate electricity yourself by turning a properly rigged bicycle wheel or the crank on some emergency radios. A photovoltaic cell, in contrast, converts light energy into direct-current electricity with no moving parts and no emissions. Energy resources Fossil energy resources are stocks of energy that have formed during ancient geologic ages by biologic and/or geologic processes. fossil biogenous energy resources (i.e. stocks of energy carrier of biological origin) e.g., hard coal, natural gas, crude oil deposits fossil mineral energy resources (i.e. stocks of energy carrier of mineral origin or non-biological origin) e.g., energy contents of uranium deposits and resources to be used for nuclear fusion processes. Recent resources are energy resources that are currently generated, for instance, by biological processes; e.g., the energy contents of biomass and the potential energy of a natural reservoir. Energy resources Available energies or energy carriers can be further subdivided: Fossil biogenous energy carriers primarily include the energy carriers coal (lignite and hard coal) as well as liquid or gaseous hydrocarbons (such as crude oil and natural gas). A further differentiation can be made between fossil biogenous primary energy carriers (e.g. lignite) and fossil biogenous secondary energy carriers (e.g. gasoline, Diesel fuel). Fossil mineral energy carriers comprise all substances that provide energy derived from nuclear fission or fusion (such as uranium, thorium, hydrogen). Energy resources The renewable energy refers to primary energies that are regarded as inexhaustible in terms of human (time) dimensions. They are continuously generated by the energy sources solar energy, geothermal energy and tidal energy. The energy produced within the sun is responsible for a multitude of other renewable energies (such as wind and hydropower) as well as renewable energy carriers (such as solid or liquid biofuels). The energy content of the waste can only be referred to as renewable if it is of non-fossil origin (e.g. organic domestic waste, waste from the food processing industry). Properly speaking, only naturally available primary energies or primary energy carriers are renewable but not the resulting secondary or final energies or the related energy carriers. However, in everyday speech secondary and final energy carriers derived from renewable energy are often also referred to as renewable. Energy resources Renewable energy. ‘Energy obtained from natural and persistent flows of energy occurring in the immediate environment’. An obvious example is solar (sunshine) energy, where ‘repetitive’ refers to the 24-hour major period. Note that the energy is already passing through the environment as a current or flow, irrespective of there being a device to intercept and harness this power. Such energy may also be called Green Energy or Sustainable Energy. Non-renewable energy. ‘Energy obtained from static stores of energy that remain underground unless released by human interaction’. Examples are nuclear fuels and fossil fuels of coal, oil and natural gas. Note that the energy is initially an isolated energy potential, and external action is required to initiate the supply of energy for practical purposes. To avoid using the ungainly word ‘non-renewable’, such energy supplies are called finite supplies or Brown Energy. Contrast between renewable (green) and finite (brown) energy supplies. Environmental energy flow ABC, harnessed energy flow DEF. Energy sources There are five ultimate primary sources of useful energy: 1. The Sun. 2. The motion and gravitational potential of the Sun, Moon and Earth. 3. Geothermal energy from cooling, chemical reactions and radioactive decay in the Earth. 4. Human-induced nuclear reactions. 5. Chemical reactions from mineral sources. Renewable energy derives continuously from sources 1, 2 and 3 (aquifers). Finite energy derives from sources 1 (fossil fuels), 3 (hot rocks), 4 and 5. The sources of most significance for global energy supplies are 1 and 4. Natural energy currents on earth, showing renewable energy system. Note the great range of energy flux 1 105 and the dominance of solar radiation and heat. Units terawatts 1012 W. For instance, total solar flux absorbed at sea level is about 12 × 1017 W. Thus the solar flux reaching the Earth’s surface is ∼20 MW per person; 20 MW is the power of ten very large diesel electric generators, enough to supply all the energy needs of a town of about 50 000 people. The maximum solar flux density (irradiance) perpendicular to the solar beam is about 1 kW m−2 ; a very useful and easy number to remember. In general terms, a human being is able to intercept such an energy flux without harm, but any increase begins to cause stress and difficulty. Interestingly, power flux densities of ∼1kW m−2 begin to cause physical difficulty to an adult in wind, water currents or waves. However, the global data of figure are of little value for practical engineering applications, since particular sites can have remarkably different environments and possibilities for harnessing renewable energy. Obviously flat regions, such as Denmark, have little opportunity for hydropower but may have wind power. Yet neighboring regions, for example Norway, may have vast hydro potential. Tropical rain forests may have biomass energy sources, but deserts at the same latitude have none (moreover, forests must not be destroyed so making more deserts). Thus practical renewable energy systems have to be matched to particular local environmental energy flows occurring in a particular region. All energy systems can be visualized as a series of pipes or circuits through which the energy currents are channeled and transformed to become useful in domestic, industrial and agricultural circumstances. Figure is a Sankey diagram of energy supply, which shows the energy flows through a national energy system (sometimes called a ‘spaghetti diagram’ because of its appearance). Sections across such a diagram can be drawn as pie charts showing primary energy supply and energy supply to end-use.Note how the total energy enduse is less than the primary supply because of losses in the transformation processes, notably the generation of electricity from fossil fuels. Energy flow diagrams for Austria in 2000, with a population of 8.1 million. (a) Sankey (‘spaghetti’) diagram, with flows involving thermal electricity shown dashed. (b)–(c) Pie diagrams. The contribution of hydropower and biomass (wood and waste) is greater than in most industrialized countries, as is the use of heat produced from thermal generation of electricity (‘combined heat and power’). Energy use for transport is substantial and very dependent on (imported) oil and oil products, therefore the Austrian government encourages increased use of biofuels. Austria’s energy use has grown by over 50% since 1970, although the population has grown by less than 10%, indicating the need for greater efficiency of energy use. Source: International Energy Agency, Energy Balances of OECD countries 2000–2001. Energy terms Energy resources Renewable energy sources can be divided into: Solar energy available annual energy 3 900 000 000 PJ/year Planetary energy available annual energy 94 000 PJ/year Geothermal energy available annual energy 996 000 PJ/year Energy stored in wind or rain, which can also be technically exploited, originate from natural energy conversion. Energy consumption Global energy consumers receive 42 % of their electricity and 28 % of all marketed energy from coal. Petroleum and other liquids (including biofuels) – 34%, are the largest source of marketed energy, followed by coal, natural gas – 23 %, renewable resources (other than biofuels) – 9%, and nuclear power – 6%. Energy consumption Utilization of renewable energies is not at all new - in the history of mankind renewable energies have for a long time been the primary possibility of generating energy. Industrial Revolution changed the energy trend: lignite and hard coal became increasingly more important. Later on, also crude oil gained importance easy transportation & processing, raw material: Crude oil (primary energy applied today). Natural gas for space heating, power provision and transportation Important due to abundantly available and only requires low investments in terms of energy conversion As fossil energy carriers increase for energy generation in Industrial countries. Renewable energy becomes secondary importance of total energy generation Energy consumption However, Undesirable Side effects of fossil fuel utilization, increasingly sensitized to possible environmental and climate effects, realized in the beginning of 21st Century. Price increase for fossil fuel energy on the global energy markets in the last few years Results: The search for environmental, climate-friendly and social acceptable, alternatives suitable to cover the energy demand has become increasingly important. Utilization of renewable sources of energy. Energy consumption Energy consumption On a regional level these fractions are strongly dependent on local and national characteristics due to varying national energy politics or available primary energy resources. For instance, in Asia the major share of the given demand for fossil primary energy carriers is covered by coal (this applies in particular to the People’s Republic of China), whereas this energy carrier is of almost no importance in regions such as the Middle East. Loss of energy Mathematically: Energy= Exergy (Available part)+Anergy (Unavailable part) The first law of thermodynamics deals with energy which is on a quantity basis. The second law of thermodynamics deals with exergy which refers to the quality of energy. Exergy is the useful portion of energy that allows us to do work and perform energy services. Source: W.A.Hermann, Quantifying global exergy resources, Energy, 31 (12), 2006, p.1685–1702, doi:10.1016/j.energy.2005.09.006 Loss of energy Energy is conserved, but not all that energy is available to do useful work. So, yes, it has something to do with reversibility and irreversibility. Both energy and exergy are things you could compute for ideal systems. For real systems, the real amount of available energy will depend on some aspects that it's not feasible to model. But for a real system energy is conserved and exergy is the energy available to do useful work. For instance: The ocean is full of energy, billions of times more than we could ever use, but it's at nearly room temperature, so it's not available energy. The center of the earth has lots of thermal energy, at a high temperature, so it would be ideal, except we can't get to it. The earth and Moon have lots of kinetic energy, but we can't tie a rope around it and harness the energy, so it's unavailable. Sunlight has considerable energy, but the physics make it difficult to impossible to grab more than 15% of it, and the costs of physical devices per square meter are still pricing that energy considerably higher than other sources, so that energy is more theoretical than practical. Renewable energy sources Solar energy Solar energy comes from the light of the sun, which means it is a renewable source of energy. We can use the sun light to create pollution free electricity. The solar cell is the system used to convert the sunlight energy into electrical energy Solar energy The main source of easily accessible renewable energy is the sun. On average the rate of solar radiation intercepted by the earth’s surface is about 8000 times as large as the average rate of world primary energy consumption. Solar energy Solar energy Solar radiation is available both directly and indirectly. Directly as solar radiation directly converted into useful energy, for instance electricity or heat. Indirectly in the form of power from wind, biomass, hydro, and marine sources. Solar energy Solar thermal signifies the thermal use of solar energy in general. Conversion of solar energy to heat requires a light-absorbing material, or a collector, which is able to distribute the absorbed radiant energy over internal degrees of freedom associated with kinetic energy of motion at the molecular level. Absorption of solar energy will rise the temperature of the collector or transfer energy to a reservoir, if the collector is connected to one. “Passive” system “natural” heat flow paths between collectors and load areas. “Active” system energy is added (pumps, etc.) to bring the collector heat gain to the load areas. Solar energy Solar energy may be converted to electricity by one of two means: Solar thermal conversion - Conversion of solar radiation to heat that in turn is added to a thermodynamic cycle to produce mechanical work or electricity. Photovoltaic conversion - Direct conversion of the solar radiant-energy photons to electricity without the benefit of a thermodynamic cycle or working fluid. The term ‘photovoltaic’ is derived by combining two words: the Greek word for light ‘photos’ the name of the electromotive force ‘volt’. Solar energy Natural processes transform solar energy into other types of energy that can be utilized by technical energy converters. Types of indirect energy Evaporation Precipitation Water flow Melting of snow Wave movements Ocean currents Biomass production Heating of Earth’s surface and the atmosphere Wind. Hydro energy Hydro-electric power is currently easily the largest of the Renewable Energy Sources. One of the most mature RE technologies. About 160 EJ is stored in rivers and seas, which is equivalent to roughly 40 % of the global energy demand, of which about one-quater is technically exploited (Europe well exploited). Controversial Hydro-electric power plants have a negative impact on nature and local conditions. Hydro energy is derived from flowing water in rivers, water streams in mountains or from man-made installations where water flows from a high-level reservoir down through a tunnel and away from the dam. A dam is built to trap water, usually in a valley where there is an existing lake. • Water is allowed to flow through tunnels in the dam, to turn turbines and thus drive generators and the electricity is produced Hydro energy Hydro energy Tidal energy is the energy due to the water waves created in the ocean. The tidal energy is also called hydropower. It is a hydropower due to raise and fall of water wave in ocean. The raise and fall of water wave is due to the gravitational forces of the moon and sun as well as the revolution of the earth. The raising and falling waves are used to rotate the turbines and hence the electricity is produced. Hydro energy The ocean tides are the direct consequences of the gravitational interaction between the Earth, Moon and Sun. Planetary energy. The different celestial bodies, in particular our moon, exchange mutual forces with Earth. The motion of the celestial bodies results in continuously varying forces at any specific point on the Earth’s surface. Hydro energy There are two basic approaches to tidal energy exploitation. Tidal Barrage Exploiting the cyclic rise and fall of the sea level through extrainment. Stillpictures Tidal Stream Generators Harnessing local tidal currents by turbines. Hydro energy Bioenergy Bioenergy (biomass) is mankind's oldest source of energy. Humans have been using biomass as an energy source for many thousands of years. Wood was the most important material for heating and cooking for a long time until it was superseded by coal, crude oil and natural gas. Biomass energy / bioenergy, is the energy stored in non-fossil organic materials such as wood, straw, vegetable oils and wastes from the forest, agricultural and industrial sectors. Bioenergy Bioenergy is arguably the one truly Renewable Energy Resource Renewable energy resource - each new crop or harvest represents a partial renewal of its resource base. (Wood fuel is a RES if “consumption rate” ≤ “renewal rate”.) Major World Energy Source ’Biomass’ from plants is one of the major world fuel sources (about 9 % of the global primary energy use, 2001) Biofuels Interest in biofuels – ethanol and biodiesel – is at an all-time high. Stored bioenergy can be used on demand. Bioenergy Wind power The history of wind power goes back many centuries: irrigation, land draining, grain milling, transportation, etc. More than 100 years ago, wind power had a dominant role in the energy supply of many countries (mechanical power). Wind energy is the kinetic energy associated with the movement of atmospheric air • Wind energy systems convert kinetic energy to more useful forms of power. • Wind energy systems for irrigation and milling have been in use since ancient times • From beginning of the 20th century it is being used to generate electric power. Wind power Wind is simple air in motion. Wind is caused by the uneven heating of the earth’s surface by the sun. During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, creating winds. This winds are used to rotate turbine blades which spins the generator to produce electricity Wind power Geothermal energy Geothermal energy is contained as thermal energy in the Earth’s interior. The origin of this thermal energy? - gravitational contraction of the earth when it was formed. - heat from the decay of the small quantities of radioactive materials contained within earth’s core. What is the problem? In the Earth’s interior, temperatures are somewhere between 3000°C and 10,000°C. Despite the fact that this heat is present in huge, practically inexhaustible quantities, it is unevenly distributed, seldom concentrated, and often at depths too great to be exploited industrially. Not strictly renewable? If steam or hot water are extracted at a greater rate than heat is replenished from surrounding forks, a geothermal size will cool down after a number of years and become exhausted. Geothermal power stations can utilize geothermal heat and convert it into electricity and/or feed it into district heating systems (e.g., Old Faithful, the most famous geyser in Yellowstone) Geothermal energy The earth can be compared with egg. The outer layer of the earth is called crest and the center layer is called Mantle and inner layer is called Core (Iron). For every 100 meters you go below ground, the temperature of the rock increases about 3 degrees Celsius. So, if you went about 10,000 feet below ground, the temperature of the rock would be hot enough to boil water. Deep under the surface, water close to the hot rock can reach temperatures of more than 148°C. Geothermal energy This is hotter than boiling water (100°C). It doesn't turn into steam because it is not in contact with the air. When this hot water comes up through a crack in the earth, we call it a hot spring and it is used to rotate the turbines and the electricity is produced. Geothermal energy The most active geothermal resources are usually found along major plate boundaries where earthquakes and volcanoes are concentrated. Most of the geothermal activity in the world occurs in an area called the Ring of Fire. Biofuel Plants use photosynthesis to grow and produce biomass. Also known as biomatter, biomass can be used directly as fuel or to produce liquid biofuel. Agriculturally produced biomass fuels, such as biodiesel, ethanol and bagasse (often a by-product of sugar cane cultivation) can be burned in internal combustion engines or boilers. Typically biofuel is burned to release its stored chemical energy. Research into more efficient methods of converting biofuels and other fuels into electricity utilizing fuel cells is an area of very active work. Liquid biofuel is usually either a bioalcohol such as such as biodiesel and straight vegetable oil. Biodiesel can be used in modern diesel vehicles with little or no modification to the engine and can be made from waste and virgin vegetable and animal oil and fats (lipids). ethanol fuel or a bio-oil Biofuel Virgin vegetable oils can be used in modified diesel engines. In fact the Diesel engine was originally designed to run on vegetable oil rather than fossil fuel. A major benefit of biodiesel is lower emissions. The use of biodiesel reduces emission of carbon monoxide and other hydrocarbons by 20 to 40% Advantage of renewable energy resources It is fact that the consumption of conventional sources of energy has caused more environmental damage than any other human activity. The use of fossil fuels such as oil and coal produce high concentration harmful gases in the atmosphere and creates so many problems such as Ozone depletion and global warming. The Non-conventional energy sources, such as the sun and wind, can never be exhausted and therefore are called renewable. They cause fewer emissions and are available locally. Consumption of renowable energy Renewable energy supplies 18% of the World’s final energy consumption. Renewables: Traditional biomass Large hydro “new” renewables Consumption of renowable energy Renewable energy comprises about 5% of global power generating capacity and supplies about 3,4% of global electricity production. Consumption of renowable energy In early 2007, the EC adopted new binding targets for 2020, including 20 percent of final energy and 10 percent of transport fuels. Source: REN21, Renewables 2007 – Global status report. Applications of renewable energies solar heat provision by passive systems (i.e. architectural measures to use solar energy), solar thermal heat provision by active systems (i.e. solar thermal collector systems), solar thermal electrical power provision (i.e. solar tower plants, solar farm plants, Dish/Stirling and Dish/Brayton systems, solar chimney plants), photovoltaic conversion of solar radiation into electrical energy (i.e. photovoltaic systems), power generation by wind energy (i.e. wind turbines), power generation by hydropower to provide electrical energy (i.e. hydropower plants), utilization of ambient air and shallow geothermal energy for heat provision (i.e. utilization of low thermal heat by means of heat pumps), utilization of deep geothermal energy resources for heat and/or power provision (i.e. utilization of the energy stored in deep porous-fractured reservoirs by means of open and closed systems) and utilization of photosynthetically fixed energy to provide heat, power and transportation fuels (i.e. energy provision on the basis of biomass). Within energy politics and energy industry, discussions on environmental effects caused by the use of a certain energy source or energy carrier are of major importance. This is why for every option of using renewable energy sources for the provision of useful energy; also selected environmental effects will be addressed. This assessment will be performed for environmental effects related to manufacturing, ordinary operation, malfunctions and the end of operation. Energy planning Complete energy systems must be analysed, and supply should not be considered separately from end-use. Unfortunately precise needs for energy are too frequently forgotten, and supplies are not well matched to end-use. Energy losses and uneconomic operation therefore frequently result. For instance, if a dominant domestic energy requirement is heat for warmth and hot water, it is irresponsible to generate grid quality electricity from a fuel, waste the majority of the energy as thermal emission from the boiler and turbine, distribute the electricity in lossy cables and then dissipate this electricity as heat. Principles of renewable energy such inefficiency and disregard for resources often occurs. Heating would be more efficient and cost-effective from direct heat production with local distribution. Even better is to combine electricity generation with the heat production using CHP – combined heat and power (electricity). Energy planning System efficiency calculations can be most revealing and can pinpoint unnecessary losses. Here we define ‘efficiency’ as the ratio of the useful energy output from a process to the total energy input to that process. Consider electric lighting produced from ‘conventional’ thermally generated electricity and lamps. Successive energy efficiencies are: electricity generation ∼30%, distribution ∼90% and incandescent lighting (energy in visible radiation, usually with a light-shade) 4–5%. The total efficiency is 1–1.5%. Contrast this with cogeneration of useful heat and electricity (efficiency ∼85%), distribution ∼90% and lighting in modern low consumption compact fluorescent lamps (CFL) ∼22%. The total efficiency is now 14–18%; a more than tenfold improvement! The total life cycle cost of the more efficient system will be much less than for the conventional, despite higher per unit capital costs, because: (i) less generating capacity and fuel are needed, (ii) less per unit emission costs are charged, and (iii) equipment (especially lamps) lasts longer. Energy planning Energy management is always important to improve overall efficiency and reduce economic losses. No energy supply is free, and renewable supplies are usually more expensive in practice than might be assumed. Thus there is no excuse for wasting energy of any form unnecessarily. Efficiency with finite fuels reduces pollution; efficiency with renewables reduces capital costs. Unexpected sources of renewable energy Underground liquid magma In Iceland, one of the world's most ambitious (and outlandish) renewable energy projects is now underway. The tiny northern nation is taking geothermal energy to a new level by tapping into liquid magma deep under the Earth's surface, where temperatures can reach 1,000 degrees Celsius. The hot magma is thought to be capable of producing 10 times more electricity than typical geothermal sources, so the cost-benefit is in favor of the Iceland Deep Drilling Project, which will source liquid magma from five kilometers below the surface using an enormous drill nicknamed "Thor." Unexpected sources of renewable energy Wind energy from trees Sourcing wind energy from trees doesn't make much sense at first, until you learn how it works. The secret energy-generating power comes from the way trees sway in high winds. Earlier this year, researchers published the results of a study that showed how the vibrations of tree movement could be successfully converted into useable energy. The proof of concept was demonstrated on tiny tree-like L-shaped steel beams wrapped with polyvinylidene fluoride (PVDF), a piezoelectric material. Although the amount of electricity produced was small -- around two volts -- the output would be magnified if a life-size piezoelectric array could be built to work with fullgrown trees in natural forests. Unexpected sources of renewable energy Bacteria and dirt batteries Taking a cue from energy-producing bacteria, scientists at Harvard University built a battery that's essentially powered by dirt. The creation of the microbial fuel cell (MFC) batteries is an energy storage breakthrough primed to aid residents of countries with absent or unstable power grids, such as regions of Africa where many people still live off the grid. MFC batteries are notoriously low in cost and can be constructed from local resources that look nothing like the batteries in your flashlight or cell phone. Instead, an MFC battery is built inside of a five-gallon bucket, which is filled with saltwater and holds a graphite-cloth anode, a chicken-wire cathode, mud, manure and a layer of sand to act as an ion barrier in the salty electrolyte solution. Unexpected sources of renewable energy Swedish trash As the world's human population continues to increase, so too does our waste production, creating a double-edged challenge to urban planners who are looking for renewable energy sources as well as efficient waste management processes. In Sweden, those two efforts are being combined and the nation is already successfully diverting 99 percent of its garbage from landfills and sending much of it to waste-to-energy (WTE) plants that turn it into electricity. Fully half of Sweden's annual 4.4 million tons of household waste goes through the WTE process, which burns waste and harvests energy from the resulting steam. Sweden's processes are so efficient that the nation actually imports 800,000 tons of trash from nearby countries to its 32 WTE plants, keeping even more garbage out of landfills. Unexpected sources of renewable energy Living Bricks Could your house be an energy-generating machine? These Living Bricks take advantage of the metabolic power of microbes to convert sunlight, wastewater and air into clean energy. Similar to Harvard's microbial fuel cell (MFC) battery made from dirt, these living bricks would put natural processes to work in order to benefit human lives. The early prototypes generate small amounts of electricity, but it's enough to power an LED lamp or another small device. Someday, the inventors hope to develop the technology to a point where entire structures can be built from "bioreactor walls" that could which could theoretically be constructed to emit their own light. Unexpected sources of renewable energy Las Vegas kinetic streetlights Millions of people walk the sidewalks of Las Vegas each year, and now some of those footsteps are generating clean renewable electricity. New York-based EnGoPLANET is harvesting energy typically lost to the ether by installing special streetlights powered by kinetic energy pads embedded in the walkways. These smart street lights are a world's first, proving that even small measures can help combat climate change by reducing dependence on fossil fuel forms of energy. The solar-kinetic streetlights are one element in the broader plan to make Las Vegas a net-zero emissions city powered completely by renewable energy. Source: Six unexpected sources of renewable Energy, https://www.engadget.com/2016/11/26/six-unexpected-sources-of-renewableenergy/ [28.11.2016] Individual assignment - Energy Sources Research Purpose: Although most of the energy consumed in the world comes from fossil fuel sources, there are many other potential sources of energy available. In all cases, there are pros and cons to our use of these sources. Some of the energy sources are limited by their availability or environmental impact; others need technological improvements before they can become widely used. For scientists and engineers, research is the best way to learn about unknown topics. This assignment calls you to examine information about energy sources and how those sources are used to produce electrical energy. You will begin to become an expert on one source of energy and report your findings back to the class. Then, you will meet with a group to discuss the various pros and cons that affect our use of different energy sources. Individual assignment - Energy Sources Research Sources: Biomass Fossil fuels Geothermal Hydropower Uranium Solar Wind Individual assignment - Energy Sources Research Research Questions Energy Source: 1. Where can the energy source be found? What is amount of the source in your country, EU, world? 2. How easy is it to gain access to these sources? 3. How do we obtain this energy? (How does it work?) What are the consequences of using these sources (fuels)? 4. What are the costs (direct and indirect) of using these sources? Are there viable alternative sources of fuel? 5. What is the current cost of the source of energy? 6. Are there different types or uses of this source? If yes, what are the differences? 7. What are the environmental impacts of your energy source? 8. What are the economic impacts of your energy source? How much does it cost per kWh? 9. What countries frequently use this source of energy? What percentage is it used in your country, EU, world? 10. What are the most common applications for this energy source? (at farms, in industry etc.) Could this source be used in a family home? Individual assignment - Energy Sources Research Assignment to be prepared invidually Form: multimedia presentation in PowerPoint Deadline: 12/11/2016 – presentation at classroom, 5-7 minutes
