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Published byTrevor Moore Modified over 8 years ago
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ENERGY Energy is the capacity of a system to do work Energy is always conserved but … … can be transformed from one form to another Energy, E (unit: 1 joule = 1 J or N m) Power, P = dE / dt (unit: 1 watt = 1 J s -1 or 1 W) (where time, t / s) 1 J is about the energy required to raise 100 g (e. g., a mobile phone) vertically 1 m against Earth’s gravity at sea-level (g =9.81 m s -2 ) I W is the power required to do this in 1 s Many different kinds of energy: kinetic, potential, mass (chemical, electrical, magnetic, gravitational, thermal, nuclear,...) Here we are interested in energy used directly or indirectly by people for heat and power, and related key issues.
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6.9 billion now World population 1950-2050 net current growth rate about 9,100 people per hour
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Economic growth
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Increased energy demand 1 quad = 1 quadrillion Btu = 10 15 Btu =1.055 10 18 J = 1.055 EJ 528 EJ world energy consumption in 2009 ↔ 16.7 TW globally or 2.5 kW per person on average
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Peak oil … and coal, gas, uranium
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Anthropogenic climate change Intergovernmental Panel on Climate Change, IPCC (2007)
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enlightened Energy Policy affordable energy on demand
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UK Energy Policy largely set by Energy White Paper (2007) and The UK Low Carbon Transition Plan (2009) UK Energy Policy
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Energy Conversion Energy cannot be created or destroyed (first law of thermodynamics). However energy in one form E x (heat, work, chemical, mass) may be converted into energy of another form E y via suitable technology.
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Contributions of Process Industries to Global Environmental Problems Many global problems arise from energy use, and resulting depletion of raw materials and increasing emissions. EnergyRaw Materials Main product(s) Co-products (waste) Process we are interested in the case where the product is energy (in a different form than input)
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World primary energy supply Sectors Industry Domestic Transport Services
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Scope Energy used in sectors: industry, transport, domestic, services (agriculture, hospitals, …) Consider main energy conversion technologies.
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Fossil Fuels coal, oil, gas power generation and transport SO x, NO x, VOC, CO, waste heat CO 2 efficient land use non-renewable sensitive to political instability?
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Nuclear fission, fusion fuel reprocessing de-commissioning short/long term radiation hazard nuclear arms no direct CO2 emissions terrorism non-renewable
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Biomass broadly CO2 neutral requires large land areas significant water usage competes with food production has niche as by-product of waste disposal
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Wind Power variable power available can be land or off- shore moderate area use intermediate technology planning?
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Water Power hydro, wave, tides, currents clean reputation low running costs can be environmentally disruptive can destroy land can arise from political oppression some real technical challenges
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Solar Power photovoltaic, passive solar heating, solar concentrators fairly efficient land use intermittent depends on latitude some cost issues with PV
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Geothermal Energy hot water from underground reservoirs or via cold water pumped from surface turbine power or direct heating depends on local geology green though undeveloped technology
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World Energy http://www.iea.org/
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UK Energy http://www.decc.gov.uk/en/content/cms/statistics/ Digest of United Kingdom Energy Statistics 2010 (“Dukes”) UK Energy in Brief 2010
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Energy Forecast (UK) central issues are energy sustainability & security remains largely fossil based throughout 21st century? off-shore wind and wave power? next generation of nuclear power? hydrogen economy?? effects of global warming may be discovered the hard way
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