Renewable Energy Resources Notes PDF

Renewable Energy Resources Photo: Copernicus 35  II. RENEWABLE ENERGY RESOURCES Renewable resources – are replenished fairly rapidly (hours to several decades) through natural processes. Examples of renewable resources: Photo: Lumberjacks Fre...

Renewable Energy Resources Photo: Copernicus 35  II. RENEWABLE ENERGY RESOURCES Renewable resources – are replenished fairly rapidly (hours to several decades) through natural processes. Examples of renewable resources: Photo: Lumberjacks Fresh Air Fresh water Fertile soil Plants and animals (biodiversity) Wood is a renewable resource and source of energy (biomass) Wind and Solar Energy Pros and Cons Abundant Clean - do not emit CO2 , thus do not contribute to air pollution or global climate change May be unstable – depends on the weather Construction/installation costs can be expensive Engineering developments and mass production have brought their prices down Hard structures cannot be easily recycled.  Wind Power The world’s fastest‐growing energy source Prices have fallen sharply in the past few years A cheaper source of electrical generation Less maintenance and safety concerns than nuclear energy Initial construction costs can be high (towers) Can affect wildlife (birds) Propeller Blades Siting requirements: Strong winds Clear hilltop Tower Turbines in prevailing wind direction Wind turbine Energy 101: Wind Turbines – US Dept of Energy (2:16 mins) https://www.youtube.com/watch?v=tsZITSeQFR0&t=136s 39 Solar Energy The Sun is a giant nuclear furnace in space, constantly bathing our planet with a free energy supply. - Energy from the sun is abundant and free - Solar energy is the most accessible and plentiful source of energy on Earth. -  Solar Energy Solar energy is electromagnetic radiation that is given off by the sun and captured to be turned into useful energy. Humans capture sunlight to turn it into useful electricity using processes like the photovoltaic effect. – The electricity produced by solar energy can be used in power grids or stored in batteries – Costs of converting solar energy into electricity continue to fall as the technology becomes more advanced and efficient Or by concentrating the solar radiation using special mirrors. Solar energy also has the advantage of producing a lower carbon footprint (less CO2) than fossil fuels, which reduces its overall environmental impact. 41  PV cells contain materials called semiconductors which allow electrons to flow through them. Solar panels of photovoltaic (PV) cells - turn sunlight directly into electricity The most common type of semiconductor used in PV cells is crystalline silicon - relatively inexpensive, abundant, and lasts a long time. Most commercial PV cells have 15-20% energy efficiency. 42 No turbines!  Solar Energy “Power Tower” A “power tower” is a form of concentrated solar thermal electrical generation. Thousands of movable mirrors focus intense energy on the central tower, where fluid is heated to drive a steam turbine. Mlenny/Getty Images 43 Pros and Cons of Solar Energy Solar energy is the least expensive energy to produce. Government incentives for homeowners and businesses make it an attractive technology to invest in. Less efficient on cloudy days and at night – storage battery is needed Solar electricity generation itself does not emit pollutants, but manufacture of solar panels produces emissions. Solar panels are currently not recyclable in most parts of the world - most solar panels are disposed of in landfills. – Europe is leading the way in recycling and reusing solar panels. Advances in solar cell technology → greater energy efficiency (>30%), longer lasting, solar windows, printable! 44  Water Power/Hydroelectric power Hydroelectric power, or hydropower, harnesses the kinetic energy of running water, mainly from large dams. Water flows downwards with gravity to spin a turbine (kinetic energy → mechanical energy) More stable/reliable than solar and wind power. Hydroelectric dams are very expensive to construct, require suitable valley sites, can affect human populations nearby and harm wildlife/ecosystems Can produce abundant electricity, but have tremendous environmental, political and social costs. Falling water produces hydroelectric power. The theory is to build a dam on a large river that has a large drop in elevation. The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is the water intake. Gravity causes it to fall through the penstock inside the dam. At the end of the penstock there is a turbine propeller, which is turned by the moving water. The shaft from the turbine goes up into the generator, which produces the power. (USGS.gov) 46 Large Dams Have Large Impacts - tremendous environmental and social costs China’s Three Gorges Dam menabrea/iStockphoto/Getty Images 47 Biomass Energy / Biofuels Developing countries Burning biomass (plant materials) remains the principal energy source for heating and cooking Developed countries Which depend on fossil fuels for most of their energy Burning agricultural wastes (e.g. straw, corn stalks) and biomass crops (e.g. reeds, elephant grass) can be highly sustainable Globally, production of these two fuels is booming, from Brazil to Southeast Asia to U.S. and Europe. 1/5 of the corn (maize) crop → Ethanol Crops with high oil content (soybeans, sunflower seed, palm oil fruits) → Biofuel Common Biofuel Sources Source: USDA Climate Hubs 49  CO2 equivalent Coal Natural gas Nuclear power Solar power Wind power Hydropower 50 Energy Conservation Much of the energy we consume is wasted Our ways of using energy are so inefficient that most potential energy in fuel is lost as waste heat Conservation involves technology innovation as well as changes in behavior. High‐efficiency automobiles - Low‐emission, hybrid gas‐electric vehicles Walking, biking, or taking public transport  Midterm Exam Arrangements Date: Wed 16th October 2024 Time slot: 10:30 – 11:30 am (Please arrive on time!) Duration of exam: 1 hour Venue: LT-J Stay seated afterwards until all exam papers have been collected and counted. Format: 50x MCQs, CLOSED-BOOK Coverage: L1 Introduction to L11 Energy Resources II Please bring your student ID card, pencil, eraser, and a [scientific] calculator 52