Fossil fuels - conventional and advanced
Transcription
Fossil fuels - conventional and advanced
Energy resources - fossil fuels Fall Fossil Fuels The development of sustainable energy systems has ‘emerged as one of the priority issues in the move towards global sustainability’ (Malkina-Pykh et al., 2002) “improving access to reliable, affordable, economically viable, socially acceptable and environmentally sound energy services and resources, taking into account national specificities and circumstances through various means such as enhanced rural electrification and decentralized energy systems, increased use of renewable energy, cleaner liquid and gaseous fuels and enhanced energy efficiency.” (Johannesburg declaration) Develop energy systems such that we balance economic development with social and environmental objectives Social Economic Environmental SED Themes/Goals Four broad themes/goals towards SED: •Improve technical and economic efficiency (Econ D) •Improve energy security (supply and infrastructure); diversifying, decentralize, increasing supply, local sources, renewable (Econ D) •Reduce environmental impact (environmental dimension) •Expand access and affordability (social dimension) Multi-objective policy and decision-making E.g. Energy and Environmental policy interlinked! Throstur Thorsteinsson (ThrosturTh@hi.is) 1 Energy resources - fossil fuels Fall Resource Classification to measure lifetime? Fossil Fuels, use and lifetime How • • • • Conventional vs. unconventional Oil Natural Gas Coal Environmental Advanced impact Use of Fossil Fuel Resources In 2008, total worldwide energy consumption was 474 exajoules (474*1018 J = 132,000 TWh). 85% fossil fuel World Total Primary Energy Supply Icel and Throstur Thorsteinsson (ThrosturTh@hi.is) Geothe rmal 0.1% Shares of energy sources in total global primary energy supply in 2008 (492 EJ). 2 Energy resources - fossil fuels For Renewable resource: continuously available or replenished quickly • examples: sunlight, biomass, hydro-power Coal Natural Oil gas Primary Years fossil fuel at the end of 2010 Reserves to production ratio (R/P) Fall energy • Can be used almost directly, coal, oil, gas Secondary energy • Produced from primary energy e.g. electricity Alternative, Measured conventional, unconventional in e.g. TOE, Joules, BTU’s, kWh Non-renewable: extracted at rate > than replenishment rate • examples: fossil fuels, nuclear fuels, metals Energy intensity • BTU energy/tons aluminum Energy efficiency • Tons aluminum/BTU´s energy • Laws of thermodynamics! Quantity, quality EROI • Energy out/Energy in Conservation Cogeneration (e.g. NGCC, combined gas and steam cycle – waste heat to produce electricity) Efficiency change Oil • Conventional (crude) • Unconventional (Oil shale, Tar sands, Heavy crude) Natural Gas • Conventional • Unconventional (Methane ice, coalbed methane) Coal • Conventional Throstur Thorsteinsson (ThrosturTh@hi.is) 3 Energy resources - fossil fuels Fall Origin Organic matter is buried in anoxic marine basins in tropical environments often in highly productive areas Incomplete biological decomposition, depth >500m Buried organic material forms kerogen, a solid, waxy organic material Kerogen is converted to petroleum during burial at temperatures of 50 to 100°C; up to 200°C for gas. More heat and pressure - higher quality fuels. Increasing pressure and heat - water pushed out, upwards migration to reservoir rock, cap rock. Petroleum migrates from source rock (usually siltstone or shale) to reservoir rock (usually more permeable) Oil will move to surface unless it hits an oil trap Thus to get oil, we need a productive area, lack of oxygen, high pressure and heat, trapping structure oil refinery is an industrial process plant where crude oil is processed and refined into useful petroleum products such as gasoline and diesel fuel. Fractional distillation An Throstur Thorsteinsson (ThrosturTh@hi.is) Primary recovery • 25-30%, flows out by own pressure Secondary recovery • 10%, flows out with help of gas or water Tertiary recovery • 10%, CO2 or NOx enhanced recovery Oil Shale: brown-black sedimentary rock consisting of kerogen (10%) and fine mineral grains • Surface or subsurface mining, vaporized • 10 times oil reserves of the Middle East • Environmentally harmful, expensive Tar Sand: unconsolidated sand and silt with bitumen • Mining, vaporizing, high viscosity • Expensive, environmentally harmful 4 Energy resources - fossil fuels Fall Peak oil is the point or timeframe at which the maximum global petroleum production rate is reached, after which the rate of production enters its terminal decline. If global consumption is not mitigated before the peak, the availability of conventional oil will drop and prices will rise, perhaps dramatically. M. King Hubbert first used the theory in 1956 to accurately predict that US oil production would peak between 65 and 70. His model, now called Hubbert peak theory, has since been used to predict the peak petroleum production of many other countries According to the Hubbert model, the production rate of a limited resource will follow a roughly symmetrical bell-shaped curve based on the limits of exploitability and market pressures. Throstur Thorsteinsson (ThrosturTh@hi.is) Best first principle in action Discoveries peak, and then production peaks Peak defined by physical scarcities - at about mid-point After peak, production declines 5 Energy resources - fossil fuels Fall Natural gas • Mixture of 80 - 90% methane, smaller amount of heavier hydrocarbon compounds • Conventional - with oil • Unconventional Coalbed methane Methane ice (>500m), marsh gas Aquifer gas Water ice, that contains methane within its crystal structure Frozen, or crystallized storage of methane Polar permafrost, in ocean sediments Throstur Thorsteinsson (ThrosturTh@hi.is) 6 Energy resources - fossil fuels Fall Origin: • Dead plants are buried in terrestrial sediments • Heat, pressure and bacterial action and lack of oxygen • First peat, then coal • Anthracite, bituminous, lignite In order of increasing energy content: 1.Peat 2.Lignite (low sulfur) 3.Bituminous (high S) 4.Anthracite (low-med sulfur) Throstur Thorsteinsson (ThrosturTh@hi.is) 7 Energy resources - fossil fuels Electricity • Increase efficiency of power/electricity generation Fall Cogeneration(steam-electricity) – polygeneration (steam, electricity, synfuels). and use less coal more natural gas A) Large scale (Coal) – IGCC. B) Small scale (Natural gas) - NGCC - can be deployed at a much smaller scales from 1 to several hundred megawatts). Clean coal Cogeneration with industry • Use cogeneration – polygeneration - synfuels Transportation • Towards use of electricity, hydrogen, biofuels, synfuels • Other advanced transportation tech. e.g. hybrids Increase the Efficiency of Power/electricity generation, and use more gas. • Gas Driven Turbines Advantages: Are as efficient as the coal driven ones NOx the only real pollution (and CO2 of course) and is only 10% of coal fired power plants. • Disadvantages: A bit more expensive Inertia prevents investment Throstur Thorsteinsson (ThrosturTh@hi.is) Increase fuel efficiency - only about 8% efficiency, use lighter cars Use Alternative Fuels • • • • Hybrids cars: Use a mixture of electricity and gasoline. Electric cars: Plug - in Biofuels: Such as ethanol, methane, biodiesel Synfuels – or syngas derived fuels: Synthetic middle distillates (SMD) Dimethyl ether (DME) • Hydrogen as an energy carrier – fuel cells 8 Energy resources - fossil fuels Recovery: damage to fragile ecosystems, water and air pollution, and waste disposal Refining: soil, water and air pollution Delivery and Use: energy to power automobiles, produce electricity, etc. Fall Household Scale • Carbon monoxide Local (community) Scale • Fuel-derived air pollution/urban pollution. Electric Power sector - particles, NOx and SOx, lead e.g. Local pollution Car exhaust - Small particles, NOx, SOx, VOC - Smog • Oil Spills: impact on water and terrestrial ecosystems, very difficult to clean. • Local impact from extraction Regional scale • Acid Rain Global Scale • Climate change Throstur Thorsteinsson (ThrosturTh@hi.is) 9