dr stefan krause, keele university, [email protected] c-change in gees: human pressures on...
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C-Change in GEES
Human Pressures on the Environment
Session 6Session 6: Energy
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These slides were last updated in December 2009
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Session Outline
1) Energy supply and demand
2) Carbon emissions
3) Alternatives to fossil fuels:
• Bio-fuel
• Hydropower
• Solar power
• Tidal power
• Wave power
• Wind power
• Nuclear power
Energy Demand
Data: 2006 Key World Energy Statistics from the International Energy Agency
GDP and Energy consumption in Japan: After the oil shocks of 1973 and 1979 Japan’s energy use stagnated while its GDP continued to grow, after 1985, however, energy consumption continued to increase with GDP
Fossil Fuels
Formed by the decomposition of buried dead organic matter over millions of years
Contain a high percentage of carbon
~85% of global energy production through the burning of fossil fuels (petroleum, coal, natural gas)
Considered a non-renewable resource because of the length of time they take to form – current consumption of fossil fuels is much higher than production
Carbon Emissions
Data source: Carbon Dioxide Information Analysis Centre
Author: Robert A Rohde
World power usage in terawatts (TW), 1965-2005
Energy Sources
Data: BP 2006 statistical review
Author: Frank de Mierlo
Biofuels - Biomass
Hydro power
Solar power
Tidal power - Wave power
Wind power
Nuclear Power
Renewable EnergySources
Solar, Wind and Biofuels
Photo: Roland Peschetz (flickr.com)
Derived from recently dead biological material, as opposed to fossil fuels that are derived from long dead biological material
Can be produced from any (biological) carbon source - usually photosynthetic plants that capture solar energy
Most common use: liquid fuels for automotive transport (increased independence from petroleum - enhanced energy security)
Ongoing discussion about biofuel production and use: • “Food vs fuel" debate • Carbon emissions levels• Sustainable biofuel production• Human Rights issues• Poverty reduction potential• Biofuel prices• Centralised versus decentralised production
Bio-Fuel
Greatest technical challenge - developing ways to convert biomass energy specifically to liquid fuels for transportation.
To achieve this, the two most common strategies are:
1. Growing sugar crops (sugar cane, and sugar beet), or starch (corn/maize), which can produce ethanol through yeast fermentation
2. Growing plants that produce oils (such as oil palm, soybean, algae, or jatropha) that can be processed to produce fuel or burnt in a diesel engine.
Wood and its by-products can be converted into biofuels such as wood-gas, methanol or ethanol fuel.
Bio-FuelProduction
Vegetable oil
• Can be used for either food or fuel• For fuel use the quality of the oil may be lower but in many old diesel
engines (equipped with indirect injection systems) vegetable oil can be used
• Direct application limited to warm climates only• In most cases, vegetable oil is used to manufacture biodiesel
Biodiesel
• Most common biofuel in Europe• Produced from oils or fats using transesterfication creating a liquid similar in
composition to mineral diesel • Chemical name is fatty acid methyl (or ethyl) ester (FAME)• Oils are mixed with sodium hydroxide and methanol (or ethanol) and the
chemical reaction produces biodiesel (FAME) and glycerol• Biodiesel can be used in any diesel engine when mixed with mineral diesel
Bio-Fuel
Bioalcohols• Biologically produced alcohols, most commonly ethanol, less commonly
propanol and butanol• Produced by microorganisms and enzymes through fermentation of
sugars or starches• Biobutanol can be used directly in a diesel engine
BioGas• Produced by digestion of organic material by anaerobes• Can be produced either from biodegradable waste materials or by the use
of energy crops fed into anaerobic digesters• Solid by-product, digestate, can be used as a biofuel or a fertilizer.
Solid biofuelsExamples include wood, grass cuttings, domestic refuse, charcoal, and
dried manure
Bio-FuelFirst-Generation Fuels
Originating from non food crops, including cellulosic biofuels
Examples:waste biomass, the stalks of wheat, corn, wood, and special-energy-or-biomass crops (e.g. Miscanthus)
Second generation (2G) biofuels: use biomass in liquid technology, including cellulosic biofuels from non food crops
Many new second generation biofuels under development, e.g. biohydrogen, biomethanol, DMF, Bio-DME, Fischer-Tropsch diesel, biohydrogen diesel, mixed alcohols and wood diesel.
Third generation (3G) biofuels: Algae fuel (“oilgae”) is a biofuel from algae
Bio-FuelSecond- and third-generation biofuels
Advantage of biofuels over fossil fuels:
- Biodegradable (relatively harmless to the environment if spilled)
- Abundance- Renewable- Cheap to harvest (in contrast to
many fossil fuels)
To replace all petroleum fuel in the US by algae-fuel would require 38,849 square kilometers of algae plantation
Bio-FuelAdvantages
Algae Plantation, Indonesia
Hydro-Power
Most abundant form of renewable energy
Produces no waste and no carbon dioxide
Worldwide, hydropower installations supplied 2998 TWh of hydroelectricity in 2006. This was approximately 20% of the world's electricity, and accounted for about 88% of electricity from renewable sources (REN21.net and US Energy Information Administration).
Generated by potential energy of dammed water driving a water turbine and generator
Amount of energy extracted from the water depends on the volume and on the difference in height (head) between the source and the water's outflow
The amount of potential energy in water is proportional to the height of the head
Country Annual Hydroelectric
Energy Production (TWh)Installed Capacity
(GW)
People's Rep. of China 486.7 145.26
Canada 350.3 88.974
Brazil 349.9 69.080
USA 291.2 79.511
Russia 157.1 45.000
Norway 119.8 27.528
India 112.4 33.600
Japan 95.0 27.229
Venezuela 74 -
Sweden 61.8 -
France 61.5 25.335
Hydro-PowerGlobal Production
Data: BP Statistical Review - Full Report 2009
Produces electricity to supply high peak demands by moving water between reservoirs at different elevations
At times of low electrical demand, excess generation capacity is used to pump water into the higher reservoir
When demand is higher, water is released back into the lower reservoir through a turbine
Pumped storage schemes currently provide the only commercially important means of large-scale grid energy storage.
Hydro-PowerPumped storage hydroelectricity
Elimination of the cost of fuel (cost to operate a hydroelectric plant is more or less unaffected by costs of fossil fuels)
Longer economic lives than fuel-fired generation, with some plants now in service having been built 50 to 100 years ago
Operating labour cost is low – usually plants are automated and have few personnel on site during normal operation
Dams may serve multiple purposes - hydroelectric plant may just be added with relatively low construction cost, offsetting the costs of dam operation (e.g. electricity from the Three Gorges Dam will cover the construction costs after 5 to 8 years)
Hydro-PowerAdvantages - Economic
Environmental damage
Disruption of surrounding aquatic ecosystems (both upstream and downstream)
Dams at the Atlantic and Pacific coasts of North America have reduced salmon populations by preventing access to spawning grounds upstream- improvement by installation of fish ladders
Additional harm of Salmon spawn when passing through turbines on their way to the sea
Altered Hydro-ecological conditions:• Water temperature• Sediment transport and resulting riverbed characteristics • Flow conditions (turbulence) • Nutrient and pollutant transport
Hydro-PowerDisadvantages
Population relocation
At three gorges dam it is estimated that 1.13 million residents have been forced to relocate; new developments have doubled that number to 2.3 million
Dam failures (e.g. Banqiao Dam failure in Southern China resulted in the deaths of 171,000 people and left millions homeless )
Hydro-PowerDisadvantages
Three Gorges Dam
Vaiont Dam
Earth continuously receives 174 petawatts of incoming solar radiation (insolation) at the upper atmosphere
However, atmospheric conditions reduce the quantity of energy reaching the Earth's surface and also diffuse approximately 20 percent of the incoming light and filter portions of its spectrum
All energy currently consumed, including heat, electricity, fossil fuels, etc., could potentially be produced in the form of electricity by solar cells.
Solar Power
Solar power systems installed in the areas defined in the map could provide more
than the world's 2006 total primary energy demand.
Usually silicon cells (photodiodes) that convert solar radiation into electricity
Photons from sunlight knock electrons into a higher state of energy
Often electrically connected in multiples as solar photovoltaic arrays
Solar PowerPhotovoltaics
Generated by the relative motion of the Earth, Sun and the Moon, which interact via gravitational forces
Water levels follow periodic highs and lows
Water level changes (tides) go along with tidal currents
Tidal energy generators use water level changes or currents to generate energy
The stronger the tide, either in water level height or tidal current velocities, the greater the potential for tidal energy generation
Tidal Power
Tidal stream systems using kinetic energy of moving water to power turbines (similarly to windmills using moving air)
Lower cost and lower ecological impact compared to barrages.
Barrages make use of the potential energy in the difference in head between high and low tides
High civil infrastructure costs, shortage of viable sites, environmental issues
Only plausible in high-velocity areas with fast natural tidal currents (west and east coasts of Canada, the Strait of Gibraltar, the Bosporus, south east Asia and Australia)
At entrances to bays and rivers, or between land masses where water currents are concentrated
Tidal Power
Several commercial prototypes and relatively new technology
Prototype projects in Norway, New York, Devon and Northern Ireland
Draw energy from currents in much the same way as wind turbines - Density of water 832 times higher than the density of air
Generator can provide significant power at low tidal flow velocities (compared with the wind speed).
Selection of location is important for the tidal turbine
Tidal PowerTidal stream generators
SeaGen – The world's first commercial tidal generator in
Strangford Lough Northern Ireland
Captures the energy of ocean surface waves
Not a widely employed technology, and no commercial wave farm has yet been established.
Plants consisting of offshore buoys generating electricity while rising and falling
Pacific Gas and Electric Company announced its support for plans to build America's first commercial wave power plant in Northern California in 2012, max of 2 MW to supply 1500 homes
Pelamis Wave Energy Converter: a floating device, sections of which articulate with the movement of the waves, creates pressurized oil to drive a hydraulic ram which drives a motor
Wave Power
Pelamis Wave Energy Converter at the port of Peniche, Portugal
Conversion of wind energy into electricity using wind turbines
Worldwide capacity of wind-powered generators was 94.1 GW in 2007
Today production equals 1% of world-wide electricity use:• Denmark 19%• Spain 9% • Portugal 9%• Germany 6% • Republic of Ireland 6%
Global increase of wind power generation by more than fivefold between 2000 and 2007
Large scale wind farms connected to electrical grids - Individual turbines for providing electricity to isolated locations
Wind Power
Complaints of noisy and visually intrusive wind turbines, "shadow flicker" caused by rotating turbine blades
Effects may be countered by changes in wind farm design.
Aesthetic issues are important for onshore and near-shore locations
Large "visible footprint" compared to other sources of industrial power (which may be sited in industrially developed areas) because wind farms often close to scenic, undeveloped areas
To reduce the concern - offshore wind developments at least 10 km from shore
Wind PowerDisadvantages
Danger to birds expected due to installation of a wind turbine
The number of birds killed by wind turbines is negligible compared to the number that die as a result of other human activities such as the environmental impacts of using non-clean power sources.
For example, in the UK, where there are several hundred turbines, about one bird is killed per turbine per year; 10 million per year are killed by cars alone
Wind PowerImpact on Wildlife
Nuclear fission chain reaction – splitting atoms (through collision with neutrons) produces free neutrons, which collide with other atoms - creates heat—which is used to boil water and drive a steam turbine.
In 2007, nuclear energy accounted for 14% of the world’s electricity production.
The US, France and Japan together account for over half of the world’s nuclear energy generation (International Atomic Energy Agency)
Nuclear generated electricity accounts for ~14% of electricity production in the UK, this figure is lower than in 2006 as a result of plant closures
The UK Government has confirmed plans to open a new generation of nuclear power stations during the 2010s – important issues over planning and site selection – 10 sites identified by government in Nov 2009.
Nuclear Power
Nuclear Power
Author: Robert A. RohdeData: International Atomic Energy Agency
Nuclear PowerGlobal Production
Authors: Ichwan Palongengi and Krzysztof Kosinski
Data: World Nuclear Association
A large nuclear reactor produces 3 cubic metres (25–30 tonnes) of spent fuel each year – a relatively small amount
It is primarily composed of unconverted uranium and other actinides (e.g. plutonium) – responsible for long term radioactvity. A small percentage of waste is fission product, which is responsible for short-term radioactivity.
Waste disposal (methods and sites) is an important part of the debate over the future of nuclear power.
UK Government 2008 White Paper: “Managing Radioactive Waste Safely: A Framework for Implementing Geological Disposal” Risks associated with radioactive waste should be considered in relation to the waste products of other energy generators – as a waste product of fossil fuel burning, CO2 and other air pollutants are responsible for ~ 2.4 million deaths per year worldwide (WHO, 2007) (as well as being responsible for accelerated climate change)
Nuclear PowerWaste Products
The International Nuclear Event Scale (INES) is used to measure the severity of nuclear accidents on a scale of 0 to 7.
Chernobyl (1986) nuclear reactor explosion is the only accident in history to score 7
A UN report (2005) concluded that the death toll includes the 50 workers who died of acute radiation syndrome, nine children who died from thyroid cancer, and an estimated 4000 excess cancer deaths in the future.
However, risk of nuclear accidents is very low, and has decreased with improved technology (as is the case with all power generators – e.g. hydropower dams)
Nuclear PowerAccidents
Strupczewski, A. (2003) ‘Accident risks in nuclear-power plants’ Applied Energy 75(1): 79-86
Nuclear PowerTerrorism
Potential security/terrorist threats associated with nuclear power include:
• Strike (e.g. bombing) on nuclear power plant
• Strike on a nuclear waste storage facility
• Theft of uranium for use in the production of nuclear weapons
Greenpeace and the Oxford Research Group have lobbied against nuclear power on the basis of security concerns
Government plans for nuclear power must include stringent plans for security and safety
Plant Isar II, Bavaria, Germany
Summary
• Energy production is a highly contentious political subject
• In moving away from a reliance on fossil fuels there are many pros and cons of alternative energy to be weighed up and countless stakeholder groups each with a different interest in promoting a particular technology
• Issues of environmental justice in planning and locating energy production are of key importance
• Different approaches to energy demand: meet growing demand with cleaner fuel vs reduce demand
• Security in supply as well as reducing emissions
This resource was created by the University of Keele and released as an open educational resource through the 'C-change in GEES' project exploring the open licensing of climate change and sustainability resources in the Geography, Earth and
Environmental Sciences. The C-change in GEES project was funded by HEFCE as part of the JISC/HE Academy UKOER programme and coordinated by the GEES Subject Centre.
This resource is licensed under the terms of the Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales license (http://creativecommons.org/licenses/by-nc-sa/2.0/uk/).
However the resource, where specified below, contains other 3rd party materials under their own licenses. The licenses and attributions are outlined below:
1. The name of the University of Keele and its logos are unregistered trade marks of the University. The University reserves all rights to these items beyond their inclusion in these CC resources.
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Author Dr Stefan Krause
Stephen Whitfield
Institute – Owner Keele University, School of Physical and Geographical Sciences
Title Energy Powerpoint Presentation
Date Created January 2010
Description Energy - Powerpoint Presentation – Part Six of Human Pressures on the Environment
Educational Level 1
Keywords (Primary keywords – UKOER & GEESOER)
UKOER, GEESOER, Fossil Fuel, Renewable, Nuclear
Creative Commons License Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales
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