geography 442 – a student-directed seminar

Renewable Energy Handbook ~ Final Project

Renewable Energy Handbook

Introduction

Purpose:

This handbook aims to evaluate four forms of renewable energy used for electricity generation in order to provide information about the most current technology and conclude which are the most environmentally safe, productive, and economically viable.  I selected these forms because they are the ones I think are either the most efficient or environmentally friendly. Further research could be conducted focusing on geothermal, hydro, and biomass.

Types of Renewable Energy:

  • Solar: Photovoltaic Systems
  • Onshore Wind Farms
  • Tidal: under water turbines
  • Nuclear Power Plants

Criteria:

  • System components
  • Life expectancy of the system
  • Efficiency
  • Amount of electricity produced
  • Consistency of electricity output
  • Cost
  • Environmental impacts

Abbreviations:

USD: United States Dollar

MW: Megawatt: 1 million watts: measurement of ability to generate electricity

MWh: Megawatt hours

m: meters

mph: miles per hour

kWh: kilowatt hours: 1000 watts: measures electricity production and consumption

EU: European Union

m/s: meters per second

Solar: Photovoltaic Systems

Photovoltaic Cells: make up photovoltaic systems, which convert solar energy (sunlight) into direct current electricity. Photovoltaic cells may be made up of various materials, which have different efficiencies and price tags. The two main groups and the constructive material included in them are[1]:

  • Crystalline Silicone = Singe Crystalline and Multi Crystalline
    • Higher cost, more efficient, harder to produce
    • Used mainly for commercial and utility
  • Thin Film = Amorphous and micromorph silicone, Cadmium-Telluride, Copper-Indium-Diselenide and Copper-Indium-Gallium-Diselenide
    • Lower cost, less efficient, easier to produce
    • Used mainly for residential

Statistics

Laboratory Efficiency[2]

  • Single Crystalline 15-18%
  • Multi Crystalline 15%
  • Thin Film 7-13%

Real Efficiency[3]

  • Crystalline Silicon 13%-20%
  • Thin Film 6%-12%

Amount of Electricity Produced[4]

  • Residential: up to 20 kW systems
  • Commercial and Utility: start at 1 MW
  • This residential system installed in North Vancouver (picture next page) supplies all of the “small energy conserving home’s power.[5]

Consistency of electricity output

  • Depends of amount of yearly sun irradiation[6]
  • Fluctuates depending on weather, season, and time of day[7]

Components of Systems[8]

  • On grid: photovoltaic cells, photovoltaic module, mounting structure, inverter
  • Off grid: those above plus, storage battery and charge controller

Life expectancy of System

  • 20 years[9]
  • 20 year warranties normally come with the panels in British Columbia[10]

Cost[11]

  • Crystalline Silicon 350 USD-550 USD per m2
  • Thin Film 250 USD-400 USD per m2
  • Operating and Maintenance 1% of Capital Investment per year
  • Ex. Vancouver Renewable Energy Cooperative has installed systems for between $15,000 – $90,00.[12]

Environmental Impacts[13]

  • No noise pollution
  • Indirect emission of CO2 during production of material for Photovoltaic cells
    • amount is negligible compared to fossil fuel
    • When system is decommissioned, the material of the cells can be recycled

Tidal: Under Water Turbines

Tidal Turbines: are turbines placed under water to be moved by the tide, just as wind moves turbines above ground. Currently there are four main types of tidal turbines that have undergone significant development[14]:

  • Rotech Tidal Turbine, Lunar Energy
  • SeaGen, Marine Current Turbines
  • Open-Center Turbine, Open-Center Hydro
  • TidEl, SMD Hydrovision

Marine Current Turbines’ SeaGen (picture below) was the first and is currently the only official tidal turbine operating in the world at a commercial level. It is installed in Strangford Narrows, Northern Ireland.[15] And as of September 2010 has been operating at full capacity after meeting both European Marine Energy Center’s and the UK Government’s Department of Energy and Climate Change’s testing protocol[16].

Statistics

Theoretical Efficiency:[17]

  • SeaGen: 75%-88%

Real Efficiency:[18]

  • SeaGen: 45-52% SeaGen

Amount of Electricity Produced

  • SeaGen at a tidal velocity of 2.4 m/s[19]
    • 10 MW per tide
    • 6 000 MWh per year

Consistency of electricity output

  • Very dependable (the tide always comes in and out)
  • Fluctuates with tidal velocity[20]
  • Tidal velocity fluctuates in two cycles; it is easy to record and average[21]
    • 23.5 hour cycle
    • 27.3 day cycle

System Components[22]

  • Rotor and Rotor Blades
    • Sea Gen: twin 16m diameter rotor blades that are able to be raised above the ocean’s surface
    • Power train: convert mechanical energy of rotor motion into electrical
    • Mooring System/Foundation
    • Tuning/Control System: provides control over rotors rotational speed and/or the blade’s pitch
    • System does not face open ocean, rather it faces Great Britain, protecting its components

Life expectancy of System

  • Minimum of 2.5 years
  • SeaGen is fully functioning and was installed in May 2008[23]

Cost[24]

  • 3 million Euros per megawatt generated to install tidal systems
  • Price expected to drop when technology is replicated on a large scale

Environmental Impacts[25]

  • No above water noise pollution
  • So far, no found damage to marine life
    • the turbine is in an area of strong current, the only sea life living there is agile enough to avoid injury by the slow rotating turbine blades
    • Underwater noise serves to alert sea life of turbines existence, to date allowing them ample time to avoid getting injured

Onshore Wind Farms

Wind Turbines: between 2 and 3 MW are installed in groups to create onshore wind farms. British Columbia’s only current operational wind farm, Bear Mountain Wind Park (picture below) installed November 2009, has 34 3 MW Turbines.[26]

Statistics

Theoretical Efficiency[27]

  • Betz Law: maximum possible is 59%

Real Efficiency[28]

  • Varies dependent on type of turbines and wind speed
    • under 50%
    • each wind turbine is set to operate at an optimal wind speed
    • if optimal wind speed 20 mph=40% efficiency, then efficiency will be lower at all other wind speeds

Amount of Electricity Produced[29]

  • Highly dependent on which turbine is used and at which site it is installed
  • Varies 250 watts-7 MG
    • typical onshore wind turbine of a 2-3 MW capacity can produce 6 million kWh per year
    • enough to power 1500 EU homes, 600 American homes[30]

Consistency of electricity output[31]

  • Electricity output has a cubic relationship to wind speed
    • a site with 13 mph of wind generates 60% less electricity than one with 15 mph
    • Varies depending on year, season, time of day, and height above ground, but it is forecastable based on past wind recorded

System Components[32]

  • Tower and Foundation
  • Rotor and Rotor Blades (glass fiber or carbon fiber reinforced plastics)
  • Nacelle: holds all turbine machinery
  • Drive Train containing:
    • Rotorshaft with bedding: connects rotor to gear box
    • Gear box: converts the mechanical energy from the rotor that’s 18-50 rpm to the approximately 1,500 rpm of the generator (not necessary in direct drive turbines)
    • Coupling: located between main shaft and gear box
    • Brake: 2 types required
      • aerodynamic: to adjust blade tips or pitch of entire blade
      • mechanical: to stop turbine completely
      • Generator: converts the mechanical energy to electrical

Life expectancy of System[33]

  • 20 years minimum with appropriate maintenance

Cost[34]

  • 3.5 million to install a modern 2 MW Turbine as tall as a 30 story building

*Note: Offshore wind farms are more expensive, but have been shown to produce more electricity because of access to more consistent wind caused by onshore and offshore ocean winds.

Environmental Impacts[35]

  • Can been seen as “encroachments on natural and rural landscape”
  • Shadow flicker: light alteration, affects residents near farms 20-100 minutes per year
  • Turbines create audible noise, although this has improved with technology
  • Depending of sensitivity of the area, construction of wind farms can affect wildlife
  • Radar interference, while was a rare problem, is now easily solved
  • Wind farms preserve open space

Nuclear Power Plants

Nuclear Reactors: control the release of energy from splitting the atoms that comprise the fuel it requires, such as uranium. The heat created from the continuous fission is used to make steam, which then turns the rotor blades of a generator and gets converted into electricity.[36] Two types of reactors are:[37]

  • Heavy water: the moderator used is water or granite
    • use natural uranium as fuel (ex. CANDU reactor used in Canada)
    • Light water: The moderator used is water or gas
      • must use enriched uranium

Statistics

Efficiency[38]

  • Capacity factor: compares how much electricity a generator actually produces with the maximum it could produce, during a specific period of time given the amount of fuel it requires
  • Generators now operate at an average of a 90% capacity factor

Amount of Electricity Produced[39]

  • Smallest single reactor plant in the US: 476 MW
  • Largest plant with 3 reactors: 3825 MW

Consistency of electricity output[40]

  • As long as there is uranium to fuel available and the reactors is in good repair there will be energy
  • Once every 1-2 years the reactor must be shut down for re-fueling, unless the reactor uses pressure tubes instead of a pressure vessel, then it can be refueled while still producing electricity

System Components[41]

  • Fuel: Uranium Oxide Pellets, arranged in tubes to form fuel rods
  • Fuel Assemblies: which are comprised of fuel rods are found in the reactor core
  • Moderator: material used to slow down neutrons released from fission so that more fission can be created
    • Water, heavy water, graphite, gas
    • Control rods: inserted or withdrawn from core to control or stop rate of reaction
      • cadmium, hafnium or boron
    • Coolant: liquid of gas that circles the core to draw heat from it
      • In light water reactors the moderator is also the coolant
    • Pressure vessel or tubes: steel vessel containing reactor core and moderator/coolant, or series of tubes holding fuel and conveying coolant through the moderator
    • Steam Generator: heat from the reactor is used to make steam, which powers the turbine to create electricity
    • Containment: 1 meter thick concrete and steel structure around the reactor core to protect from radiation in case of malfunction

Life expectancy of System

  • Oldest functioning plant in the US is 41 years old[42]

Cost[43]

  • 1400-3500 per KW of capacity
  • Production: 1.68 cent per KWh
    • includes a 0.1 cent USD waste disposal charge in the US
    • Decommissioning in US: 300 millions USD (included in production costs)

Environmental Impacts

  • Uranium ore, the natural from of fuel, must be mined[44]
    • Canada is the second largest producer
    • Nuclear waste classified by radioactivity:[45]
      • Low level: slightly contaminated clothing and items
      • Intermediate level: ion containing columns from the nuclear reactor’s cooling system
      • High level (HLW): spent fuel
    • High level waste are stored until it returns to containing a natural level of radioactivity[46]
      • This process of half life decay takes 500 years[47]
      • During which the waste must be stored in deep geological repositories[48]
    • Alternatively, it is possible to reprocess HLW
      • Only practiced in UK, Japan, India, Russia and France[49]

Summary

It goes without saying that if you live in Alberta you will not be installing a tidal turbine, just as if you live in Alaska you will not be considering solar panels. I will take these renewable electricity-generating technologies out of the context of geographical dependence, in order to evaluate them solely on their own merit.

To begin, each of these technologies creates no CO2 emissions from electricity production and the minimal CO2 emissions associated with the production of system components is much less then those associated with fossil fuels. There are slight variations and biased debates on which systems themselves are the most or least environmentally friendly, but many of these are opinion based as it is challenging to calculate the exact emission of the assembly plus all each part that goes into producing a renewable energy system.

From a standpoint of efficiency and amount of electricity produced, nuclear energy comes in a solid first place.  This also means that nuclear power plants pay off their rather large capital costs in a timely fashion. Nuclear power plants have a longer recorded life expectancy than any of the other forms of renewable energy looked at here.  It is the category of environmental impacts and the issue dependency on fuel, where nuclear energy struggles. Some readings even suggest that there is only a thirty year supply left of uranium in the ground.

In comparison solar, wind, and tidal energy are more “renewable” in the most basic sense of the word. They rely on natural elements (sun, wind and tide) that are not in any imaginable limited supply. There are also zero wastes produced by electricity generation from these sources, unlike nuclear. While nuclear costs the most by far, as mentioned above it covers its capital costs by producing large amounts of electricity to sell. Solar and Wind systems are comparable in cost, while tidal is expensive because it is a newer and less developed technology. As the technology of each renewable energy system is replicated on a large scale, the price for that system will fall.

Between wind, tidal and solar I believe that it comes down to environmental impact, efficiency, diversity, and consistency. Solar, while not very efficient compared to wind and tidal is more diverse. Solar systems can be installed on cars, boats, the sides of high rises and the roofs of homes, or in large solar farms. They also do not have the minor environmental impacts that wind farms do. Solar and wind systems have the same life expectancy. Wind and Tidal are both more efficient than solar, and tidal is more consistent and efficient then solar and wind.  The problem with tidal is that it is a recent technological development. This means that its production of electricity on a commercial basis has not been able to be assessed for system life span or long-term environmental effects.

If tidal electricity-generating systems continue to have a low environmental impact as well as prove to have a system life expectancy comparable to wind as solar, I would say that tidal is the most environmentally safe, productive, and will become economically viable.  Nuclear power is by far the most productive and therefore economically viable. I have not chosen it as the most environmentally safe, productive, and economically viable because of the weight I put on environmental impact. Even through the fuel waste can now be completely reprocessed, it is only reprocessed in a small number of countries compared to how many countries use nuclear power, also the uranium ore must still originally be mined from the ground. For me the purpose of renewable energy is to work with our environment, lessen our dependence on combusting fuel requiring energies, and begin to interact with our environment in a way that does not harmfully take from or dispose of materials into it.

[1] Solar Industries Association, “Solar Electric (Photovoltaic),” Solar Technology and Products, 2010, 12 Dec 2010 <http://www.seia.org/cs/solar_technology_and_products/solar_electric_photovoltaic>.

[2] IEA Photovoltaic Power Systems Programme, “Technical Concepts and Progress,” Photovoltaics in Brief – a PV snapshot, 2008, 12 Dec 2010 <http://www.iea-pvps.org/>.

[3] IEA Photovoltaic Power Systems Programme, “PV Status Today,” IEA PV Road Map, Oct 2010, 12 Dec 2010 <http://www.iea-pvps.org/home.htm>.

[4] Ibid 10.

[5] Vancouver Renewable Energy Cooperative, “Portfolio,” 2010, 12 Dec 2010

<http://www.vrec.ca/?page_id=8>

[6] IEA Photovoltaic Power Systems Programme, “PV Status Today,” IEA PV Road Map, Oct 2010, 12 Dec 2010 <http://www.iea-pvps.org/home.htm>.

[7] The Society Promoting Environmental Conservation, “Photovoltaic Panels,” Energy, 2010, 12 Dec 2010 <http://www.spec.bc.ca/pv-panels>.

[8] IEA Photovoltaic Power Systems Programme, “PV Status Today,” IEA PV Road Map, Oct 2010, 12 Dec 2010 <http://www.iea-pvps.org/home.htm>.

[9] IEA Photovoltaic Power Systems Programme, “Technical Concepts and Progress,” Photovoltaics in Brief – a PV snapshot, 2008, 12 Dec 2010 <http://www.iea-pvps.org/>.

[10] The Society Promoting Environmental Conservation, “Photovoltaic Panels,” Energy, 2010, 12 Dec 2010 <http://www.spec.bc.ca/pv-panels>.

[11] IEA Photovoltaic Power Systems Programme, “PV Status Today,” IEA PV Road Map, Oct 2010, 12 Dec 2010 <http://www.iea-pvps.org/home.htm>.

[12] Vancouver Renewable Energy Cooperative, “What does it cost?” Photovoltaics – Electricity, 2010, 12 Dec 2010 <http://www.vrec.ca/?page_id=11>.

[13] European Photovoltaic Industry Association, “Environmental Impacts,” Solar PV, n.d., 12 Dec 2010 <http://www.epia.org/solar-pv/environmental-impact.html>.

[14] Natural Resources Canada, “Review of Marine Technologies and Canada’s R&D Capacity (pfd),” Canmet Energy, Sept 2008, 12 Dec 2010 <http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/eng/renewables/marine_energy/publications.html>.

[15] Marine Current Turbines, Technology, 2010, 12 Dec 2010 <http://www.marineturbines.com/21/technology/>.

[16] Renewable Energy Focus, “DNV confirms SeaGen tidal turbine performance,” News – Wave and Tidal Energy, 3 Sept 2010, 12 Dec 2010 <http://www.renewableenergyfocus.com/ view/12197/dnv-confirms-seagen-tidal-turbine-performance/>.

[17] Ibid.

[18] Marine Current Turbines, Technology, 2010, 12 Dec 2010 <http://www.marineturbines.com/21/technology/>.

[19] Ibid.

[20] Ibid.

[21] Natural Resources Canada, “Review of Marine Technologies and Canada’s R&D Capacity (pfd),” Canmet Energy, Sept 2008, 12 Dec 2010 <http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/eng/renewables/marine_energy/publications.html>.

[22] Ibid.

[23] Marine Current Turbines, Technology, 2010, 12 Dec 2010 <http://www.marineturbines.com/21/technology/>.

[24] Tidal Energy, “SeaGen,” n.d., 12 Dec 2010 <http://www.tidalenergy.eu/sea_gen.html>.

[25] Marine Current Turbines, “Environmental Impact,” Technology, 2010, 12 Dec 2010 <http://www.marineturbines.com/21/technology/29/environmental_impact/>.

[26] Canadian Wind Energy Association, “List of Wind Farms in Canada,” Wind Farms, 2010, 12 Dec 2010 <http://www.canwea.ca/featuredWindFarm_e.php?farmId=104>.

[27] FT Exploring, “Wind Turbines and Energy in the Wind,” Energy in the Wind, 2010, 12 Dec 2010 <http://www.ftexploring.com/energy/wind-enrgy.html>.

[28] Ibid.

[29] European Wind Energy Association, “FAQ,” About Wind Energy, 2010, 12 Dec 2010 <http://www.ewea.org/index.php?id=1884>.

[30] Wind Industry, “Wind Energy Today and Tomorrow,” Wind Basics, 2010, 12 Dec 2010 <http://www.windustry.org/wind-basics/learn-about-wind-energy/wind-basics-wind-energy-today-and-tomorrow/wind-energy-today-and>.

[31] Wind Industry, “Know Your Wind,” Wind Basics, 2010, 12 Dec 2010 <http://www.windustry.org/wind-basics/learn-about-wind-energy/wind-basics-know-your-wind/know-your-wind>.

[32] World Wind Energy Association, “The Structure of a Wind Turbine – An Overview,” Technology and Planning, 2006, 12 Dec 2010 <http://www.wwindea.org/technology/ch01/estructura-en.htm>.

[33] World Wind Energy Association, “Planning of Wind Farms – An Overview,” Technology and Planning, 2006, 12 Dec 2010 <http://www.wwindea.org/technology/ch02/estructura-en.htm>.

[34] Wind Industry, “Wind Energy Today and Tomorrow,” Wind Basics, 2010, 12 Dec 2010 <http://www.windustry.org/wind-basics/learn-about-wind-energy/wind-basics-wind-energy-today-and-tomorrow/wind-energy-today-and>.

[35] Wind Industry, “Why Wind Energy?,” Wind Basics, 2010, 12 Dec 2010 <http://www.windustry.org/wind-basics/learn-about-wind-energy/wind-basics-why-wind-energy/why-wind-energy>.

[36] World Nuclear Association, “Electricity Generation – Nuclear Reactors,” How Nuclear Power Works, n.d., 12 Dec 2010 <http://www.world-nuclear.org/how/npreactors.html>.

[37] Ibid.

[38] US Energy Information Association, “Frequently Asked Question – Electricity,” Frequently Asked Questions, 2010, 12 Dec 2010 <http://www.eia.doe.gov/ask/electricity_faqs.asp#elec_gen_cap>.

[39] Ibid.

[40] World Nuclear Association, “Electricity Generation – Nuclear Reactors,” How Nuclear Power Works, n.d., 12 Dec 2010 <http://www.world-nuclear.org/how/npreactors.html>.

[41] Ibid.

[42] US Energy Information Association, “Frequently Asked Question – Electricity,” Frequently Asked Questions, 2010, 12 Dec 2010 <http://www.eia.doe.gov/ask/electricity_faqs.asp#elec_gen_cap>.

[43] Nuclear Power Education, “Cost of Nuclear Power.” 27 Jun 2010, 12 Dec 2010  <http://nuclearinfo.net/Nuclearpower/WebHomeCostOfNuclearPower>.

[44] World Nuclear Association, “Uranium in Canada,” Public Information Service, Nov 2010, 12 Dec 2010 <http://www.world-nuclear.org/info/inf49.html>.

[45] Canadian Nuclear Energy Association, “Management of Used Nuclear Fuel and Waste,” Nuclear Facts, Nov 2009, 12 Dec 2010 < http://cna.ca/english/nuclear_facts/management_used_nuclear_fuel.html>.

[46] World Nuclear Association, “Waste: Safe Containment vs. Disastrous Disposal,” n.d., 12 Dec 2010 <http://www.world-nuclear.org/why/wastecontainment.html>.

[47] Canadian Nuclear Association, “Management of Nuclear Fuel and Waste,” Nuclear Facts, Nov 2009, 12 Dec 2010 < http://www.cna.ca/english/nuclear_facts/management_used_nuclear_fuel.html>.

[48] International Energy Agency, “IEA Nuclear Roadmap,” Technology Roadmaps, 2010, 12 Dec 2010  <http://www.iea.org/subjectqueries/keyresult.asp?KEYWORD_ID=4156>.

[49] World Nuclear Association, “Processing of Used Nuclear Fuel,” 21 Oct 2010, 12 Dec 2010 <http://www.world-nuclear.org/info/inf69.html>.