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p. 1
Other Renewable Energy Sources
Jürgen Scheffran
Institute of Geography, CliSAP/CEN
Universität Hamburg
“Energy Landscapes and Climate Policy" (63-951)
Lecture 5, June 2, 2016
p. 2
HYDRO POWER
Gordon Dam, Tasmania Hoover Dam, USA
p. 3
Development of large dams
Large dam: higher than 15 m
p. 4
World hydropower generation (TWh by region)
Adapted from BP 2010
Source: IPCC 2011 SRREN, Special Report on Renewable Energy Sources and Climate Change Mitigation,
http://srren.ipcc-wg3.de/report
p. 5
Regional hydropower technical potential in 2009
Source: IPCC 2011 SRREN, based on IJHD 2010
p. 6
Energy potentials
p. 7
Regional hydropower technical potential (2009)
Source: IPCC 2011 SRREN, based on IJHD 2010
p. 8
Major hydroelectricity producer countries
Source: IPCC 2011 SRREN, based on IJHD 2010
p. 9
Hydropower plant investment cost as function of plant capacity (for undeveloped sites)
IPCC 2011 SRREN, adapted from Hall et al. (2003)
p. 10
Gross hydropower potentials in EU-MENA
adapted from /Lehner et al. 2005
p. 11
Total power potential of water energy resources in the 50 states of the USA
Source: http://www1.eere.energy.gov/water/pdfs/doewater-11263.pdf
p. 12
Hydropower problems and conflicts
About 45.000 large dams (>15 meter)
Social, ecological and economic problems
Massive change in landscape
Loss of living conditions of population
Enforced resettling (40-80 mio people)
Damage for the environment (river ecology)
Loss of cultural heritage
Unbalanced distribution of benefits and risks
Profits for firms, banks, suppliers and big customers of energy
Disadvantage for small farmers, fishermen, settlers and indigenous people
Impact of the protest movement
Media attention to protest, withdrawal of the World Bank
„Declaration of Curitiba“, World Commission on Dams (WCD)
p. 13
Euphrat-Tigris water projects
Impact on environment and society:
•382 villages affected, ca. 200,000 people resettled
•Atatürk Dam affected 55,300 people: compensation insufficient
•Flooding of Lake Assad: forced displacement of ca 4,000 families
•Reduced water from increased evaporation
•Low water quality in Iraqi Euphrates because polluted irrigation water from Turkey and Syria
•Increased salinity of Euphrates in Iraq, lower suitability as drinking water.
•Effect on geologically fragile Mesopotamian Marshes and freshwater fish habitats in Iraq.
•Flooding of many archaeological sites and other places of cultural significance.
State limits
Limits of hydrographic unit
Irrigation cultivation
Planned expansion GAP
Hydro dams
Barrages
Hydro station
p. 14
Three Gorges Hydro Project
p. 15
Global wind resource map (5 km x 5 km resolution)
Source: IPCC (2011) SRREN
p. 16
Physics of wind power
Wind energy is the kinetic energy of air in motion, flowing through an
area A during time t:
ρ : density of air; v : wind speed; Avt : volume of air passing through A
Avtρ is mass m passing per unit time.
Power is energy per unit time, so the wind power for rotor area A is:
Wind power is proportional to the third power of the wind speed;
Power increases eightfold when the wind speed doubles.
p. 17
Annual average wind speed in EU-MENA at 80 m above ground level in m/s
Source: Prepared by DLR with data from ECMWF, ISET for /WBGU 2003/
p. 18
US wind resources
p. 19
Wind energy, electricity demand and instantaneous penetration levels
Data for (a) West Denmark for a week in January 2005, and (b) Ireland for two days in April 2010.
Source: IPCC 2011 SRREN: based on (a) www.energinet.dk; (b) www.eirgrid.com
p. 20
World wind energy generation
Source: Vital Signs 2011
p. 21
Top-10 countries in cumulative wind power capacity
Source: IPCC 2011 SRREN, based on GWEC 2010
p. 22
Approximate annual average wind electricity penetration
Source: IPCC 2011 SRREN, based on Wiser and Bolinger 2010
p. 23
Growth in size of commercial wind turbines
Source: IPCC (2011) SRREN
p. 24
Development of wind-generation costs based on Danish experience
Morthorst, 2004
p. 25
Conflict potential of wind power
Change of landscape
Noise emission
Shadow generation, „Disco effect“
Threatening of birds
Substitution potential
Profitableness
Build back
p. 26
OCEAN ENERGY
Tidal power plant La Rence, France (www.industcards.com/hydro-wave-tidal.htm)
p. 27
Ocean energy
Theoretical global ocean energy resource
Capacity
(GW)
Annual gen.
(Exajoule EJ) Form
5,000 180 Marine current power
20 7,2 Osmotic power
1,000 36 Ocean thermal energy
90 2,9 Tidal energy
1,000—9,000 29—290 Wave energy
Huge amounts of kinetic energy in ocean water: conversion to electricity
International Energy Agency, Implementing Agreement on Ocean Energy Systems (IEA-OES), Annual Report 2007
p. 28
Use of tidal power
Tidal energy differs from other energy sources: energy extracted from potential and kinetic energies of earth-moon-sun system.
Ocean tides produce variations in ocean water level along shores.
Water level fluctuations fill and empty natural basins along shoreline, suggesting that the currents flowing in and out of these basins could be used to drive water turbines connected to generators. The technology employed is very similar to that of low-head hydropower.
To enhance efficiency, dam like structures can be built across the mouths of natural basins, with gates or channels to direct the natural flow through turbine locations in sequence with the tides
Turbines designed to convert water flow into electricity.
Intermittent flow limits effective duty factor, about one third as hydroelectric power plant of same peak capacity.
p. 29
Tidal ranges globally
Source: Bent Sörensen, Renewable Energy, 3rd Edition,Elsevier Academic Press, 2004, p. 263.
p. 30
Tidal range in North Europe
Source: Bent Sörensen, Renewable Energy, 3rd Edition,Elsevier Academic Press, 2004, p. 260.
Measured in meter
p. 31
Potential reductions in investment costs for wave and tidal current energy devices
Source: IPCC 2011 SRREN
p. 32
Ocean waves
Designs for converting wave energy to electricity.
Floats anchored to bottom or underwater plate,
heaving and pitching floats
oscillating water columns
flexible bag surge devices.
Highest linear power densities of average incident mechanical wave power occur in: NE Atlantic (Norway, Scotland, and England) and Southern Ocean (Australia) regions.
Rough seas locations/designs suffer from high capital and operation cost.
Projected average capacity factors 32%–38%, for highest capital cost with capacity factor 60%.
Commercial wave electric power not bright.
p. 33
Global offshore annual wave power level distribution
IPCC 2011: SRREN, based on Cornett 2008
p. 34
Regional theoretical wave power
IPCC 2011 SRREN, basedn on Mørk et al. 2010
p. 35
Oscillating water column converter
Source: Brown/Skispy 1986
p. 36
Surface ocean currents showing warm (red) and cold (blue) systems
IPCC 2011 SRREN, based on UCAR 2000
p. 37
Worldwide average ocean temperature differences (°C between 20 and 1,000 m water depth)
IPCC 2011 SRREN based on Nihous 2010
p. 38
Ocean Thermal Energy
Accessible ocean thermal differences lie between about 10–20 degree Kelvin at warm fluid temperatures of about 290 degrees Kelvin. Thus ideal thermodynamic efficiencies are only a few percent, and real system efficiencies can be as small as 1%.
Since energy source is "free," primary consideration is capital cost per unit capacity and operation and maintenance cost per unit power production (including net cost of environmental impact).
One approach is to use ammonia as a working fluid in a closed system heat exchange loop. The possibility of adverse impact from ammonia spills can be a significant consideration.
Mass of piping and other equipment per unit power production can be quite large.
p. 39
Ocean thermal energy conversion (OTEC)
Source: Wikipedia
Ocean thermal energy conversion (OTEC) uses ocean thermal gradient caused by solar heating
of surface water which is strongest in tropics. In a few remote island locations physical and
economic conditions make OTEC potentially interesting as energy source.
p. 40
OTEC in Hawaii
Source: Wikipedia
p. 41
Ocean energy
Ocean or marine energy/power: energy carried by ocean waves, tides, currents,
salinity, and ocean temperature differences (not off-shore wind power).
IPCC 2011 (SRREN): „Technologies for harnessing ocean energy are probably the
least mature of the six principal forms of renewable energy ... but the energy resources
contained in the world’s oceans easily exceed present human energy requirements.“
Ocean energy could be used to supply electricity and for potable water production.
Some potential ocean energy resources (ocean currents, osmotic power from salinity
gradients), are globally distributed, other forms have complementary distribution.
Ocean thermal energy is principally distributed in the Tropics around the Equator (0°
– 35°), whilst wave energy principally occurs between latitudes of 40° - 60°.
Some forms of ocean energy (ocean thermal energy, ocean currents, salinity
gradients and wave energy), may generate base load electricity.
With the exception of tidal rise and fall energy, which can be harnessed by the
adaptation of river-based hydroelectric dams to estuarine situations, most ocean power
technologies are presently immature.
None can be truly characterized as commercially competitive with the other lowest
cost forms of renewable energy – wind, geothermal and hydroelectric energy.
p. 42
GEOTHERMAL ENERGY
Nesjavellir Geothermal Power Plant in Iceland
p. 43
Temperature in the Earth
From: Alyssa Kagel, Diana Bates, Karl Gawell, A Guide to Geothermal Energy and the Environment, Geothermal Energy Association,
Washington, D.C., 2005, www.geo-energy.org.
4000 deg.
5000 deg.
p. 44
Geothermal energy flow
Overall flow of energy into, around, and throughout the Earth’s layers
Most geothermal energy reaching the earth's surface comes from radioactive decay energy coming up from the mantle
Temperature differences between one spot on Earth and another spot can be used to turn a heat engine, or to transfer thermal energy.
Two points of temperature difference must be in close proximity, and the difference in temperature must be large in magnitude.
Average geothermal flows useless for economic electrical power generation.
Temperature gradient in top layers of oceans is larger and in reverse direction of geothermal gradient in lithosphere.
While total flow of geothermal energy to earth's surface is only 1/2,400 of solar flux on the surface on average, geothermal flow is still quite large at ca.1000 exajoules per year.
p. 45
Energy flow across Earth's
surface
The flow diagram depicts energy flows across the earth's surface. The units are joules per calender year.
Adapted from Energy Resources: Geology, Supply and Demand, Edited by Brown, G. C. and Skispy, E. Open University Press, Philadelphia © 1986
p. 46
Geothermal reservoirs
Source: Geothermal Today, 1999 Geothermal Energy Program Highlights, U.S. DoE, http://www.nrel.gov/docs/fy00osti/27820.pdf
Geothermal resources usable for energy production are vapor-dominated sources that can be used directly to drive turbine.
If vapor contains noxious gases exhaust may be reinjected into ground.
Pressurized hot water with dissolved minerals (brine) for electricity generation by flashing brine to steam and using steam to drive turbine. Hot water may also be used for heating swimming pool in resort area.
p. 47
Geothermal energy system
From Renewable Resources in the U.S. Electricity Supply, Energy Information Administration, © February, 1993.
p. 48
Growth of the globally installed capacity of geothermal power production
Source: Global Energy Assessment, based on Bertani, 2010
p. 49
Geothermal heat flow and installed electric capacity (by country in 2009)
Worldwide average heat flow in mW/m2 and tectonic plates boundaries
IPCC 2011 SRREN, adapted from Hamza et al. 2008
p. 50
Mapping of the 10.7 GW installed geothermal electric capacity in 2009
Source: Global Energy Assessment, based on Bertani, 2010
p. 51
Solar Energy
Represents the entire electromagnetic radiation (visible light, infrared, ultraviolet, x-rays, and radio waves).
Originates from the thermonuclear fusion reactions in the sun, likely available for another five billion years.
p. 52
The generalized energy budget of earth and its atmosphere (McKNIGHT & HESS 2008)
Earth‘s solar radiation balance
p. 53
Global solar irradiance at Earth’s surface (W/m2)
(a) December, January, February (b) June, July, August
Source: ISCCP Data Products 2006
averaged over the period 1983 to 2006
p. 54
Annual global solar irradiation on surfaces tilted South with latitude angle in kWh/m²/year
Source: Prepared by DLR with data from ECMWF 2002 for WBGU 2003
p. 55
Solar resources in the USA
p. 56
Solar resources in Germany
p. 57
Annual total technical potential of solar energy for various regions of the world
IPCC 2011 SRREN Rogner et al., 2000
p. 58
Intermittency of solar power
http://www.megawattsf.com/images/CEIC_08_04_spf.gif http://www.basinandrangewatch.org/images/real%20power%20o
utput%20of%20solar%20array%20in%20arizona.jpg
p. 59
Solar power technologies
p. 60
Direct solar energy technologies
Passive heating effect can be used successfully and economically
Energy of solar irradiance
to produce thermal energy (heating or cooling, either through passive or active means),
to meet direct lighting needs
to produce electricity using photovoltaics (PV) and concentrating solar power (CSP),
and, potentially, to produce fuels that might be used for transport and other purposes.
p. 61
Direct solar energy technologies
The technology maturity of solar applications ranges from R&D (e.g., fuels produced from solar energy), to relatively mature (e.g., CSP), to mature (e.g. passive and active solar heating, and wafer-based silicon PV).
Many but not all of the technologies are modular in nature, allowing their use in both centralized and decentralized energy systems.
Solar energy is variable and, to some degree, unpredictable, though the temporal profile of solar energy output in some circumstances correlates relatively well with energy demands.
Thermal energy storage offers the option to improve output control for some technologies such as CSP and direct solar heating.(IPCC 2011, SRREN)
p. 62
Passive thermal solar system (thermosyphon)
Source: IPCC SRREN (2012)
p. 63
Evacuated-tube collectors
Thermal solar collectors
Source: IPCC SRREN (2012)
p. 64
Active solar thermal system
Source: IPCC SRREN (2012)
p. 65
Passive-active solar systems in a house
Building-integrated photovoltaic/thermal (BIPV/T) roof heats ventilated
slab or domestic hot water (DHW) through heat exchanger;
HRV is heat recovery ventilator
Source: IPCC SRREN (2012)
Passively heated home uses about 60-75% of the solar energy that hits its walls and windows.
Well-designed passive solar home can reduce energy bills by 75% with an added construction
cost of only 5-10%.
About 25% of energy is used for water and space heating.
p. 66
Solar-thermal electricity: parabolic dishes and troughs
Focus sunlight on a smaller receiver for each device; the heated liquid drives a steam engine to generate electricity.
The first of these Solar Electric Generating Stations (SEGS) was installed in CA by an Israeli company (Luz International).
Output was 13.8 MW; cost was $6,000/peak kW and overall efficiency was 25%.
p. 67
Solar central receiver or power tower
Large array of two-axes tracking mirrors (heliostats) reflect direct solar radiation onto a fixed receiver located on top of a tower.
When hundreds of heliostats concentrate radiation at one point, the solar furnace, the tremendous amount of heat generated can produce high-temperature steam or other gas which expands through a turbine to produce electricity.
Within the receiver, a fluid (water, air, liquid metal and molten salt) transfers the absorbed solar heat to the power block, where it is used to heat a steam generator.
Advanced high-temperature power tower concepts: heat pressurized air to over 1000oC and feed to gas turbines or modern combined cycles. The plant cycle, complete with turbine, condenser, and pump, is similar to plants which use fossil fuels or nuclear fission for their original energy source. 10-MW solar power plant in Barstow, CA, with 1900 heliostats
(6m x 6m) and central 90m tower
p. 68
Basic concentrated solar power configurations
parabolic trough linear Fresnel reflector
central receiver/power tower dish systems
Richter et al. 2009
p. 69
Concentrated solar collectors
p. 70
Solar Thermal Towers
PS10
PS20
Planta Solar 20 (PS20) solar thermal energy plant in Sanlucar la Mayor in Andalusia, Spain (Wikipedia)
p. 71
Comparison of different CSP technologies
Source: IRENA
p. 72
Installed and planned concentrated solar thermal electricity plants by country
IPCC 2011 SRREN, adapted from Bloem et al. 2010
p. 73
Direct conversion into electricity: Schematic cross-section of a solar cell
Source: Global Environmental Assessment 2012
1. Photons in sunlight hit the solar panel and are absorbed by semi-
conducting materials, such as silicon.
2. Electrons (negatively charged) are excited from molecular/atomic
orbital and either return to its orbital or travel through the cell until it
reaches an electrode.
3. An array of solar cells converts solar energy into a usable amount of
direct current (DC) electricity.
p. 74
PV Flexibility
Stand-Alone
• Water pumps
• Fans
Battery Backup
• Isolated Areas
Generator Backup
Hybrid
• Remote applications
Grid Connected
• Grid storage
Utility Scale
• Easy & Quick to build
p. 75
Regional indicators of photovoltaics
PV Module Production by Region 1997-2015
PV Industry Production by Region (2005-2015)
Global Cumulative PV Installation until 2015
Global Cumulative PV Installation
by Region 2015
Source: https://www.ise.fraunhofer.de/de/downloads/pdf-
files/aktuelles/photovoltaics-report-in-englischer-sprache.pdf
p. 76
Solar price experience or learning curve for silicon PV modules
Data source: Maycock (1976-2003); Bloomberg (2010).
p. 77
Trends in conversion efficiencies for various laboratory solar cell technologies
Source: Global Energy Assessment 2012, based on Kazmerski 2011
p. 78
State of the art and possible development of commercial PV module efficiencies
Source: IEA 2010
p. 79
Microenergy and rural development: Solar Home Systems in Bangladesh
Cumulative sales of solar home systems (SHS)
by Grameen Energy in Bangladesh (Source: http://www.gshakti.org/#)
p. 80
Thermochemical routes for solar fuels production
IPCC SRREN (2012)
p. 81
Hydrogen
Hydrogen can be used as an energy carrier
Hydrogen can be created from water through a process called “electrolysis”
• DC current is used to split water into hydrogen and oxygen
Energy from renewable sources, like solar power, can be used to manufacture hydrogen
Commercial feasibility of solar generated hydrogen is far off
p. 82
Renewable energy network between Europe and Africa?
p. 83
Advantages of solar power
Abundant energy resource (electromagnetic radiation): Sun emits 3.86 x 1026 watts, at earth's orbit of 1.496 x 108 km gives average insolation at top of earth's atmosphere of 1.373 kW/m2
Energy reaching the earth: 30 days of sunshine reaching Earth have the energy equivalent to all fossil fuels.
Only sun’s pure radiant energy reaches Earth, leaving polluting byproducts of the thermonuclear reactions on the sun.
Fuels most types of renewable energy resources
Place something in the path of sunlight to increase its temperature
Energy independence: less reliance on fossil fuel, broader energy portfolio
Low-carbon energy source
Self-sufficiency, consumers becoming “producers; decentral energy production and distribution (end-user)
Diversity of solar energy use, connection to Hydrogen Economy
p. 84
Disadvantages of solar power
Low energy density compared to nuclear or fossil fuels
Intermittency: Sunshine not consistent (night, winter, clouds)
Solar energy often is a diffuse source that needs to be concentrated to be used as heat and electricity.
Comparably high energy costs (cell price)
Cells can break or degrade due to environmental conditions
Impact on landscape can be small or large
Environmental impact at production
Physical complexity can be drawback for applications.
Possible mechanisms: collection, conversion, storage.