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Energy_20and_20Enviro-Arafat-Part_20VII

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									                  Energy and Environment


     Environmental Impacts of
     Renewable Energy-Part II
                                 Dr. Hassan Arafat
                              Department of Chem. Eng.
                                An-Najah University



(these slides were adopted, with modification, from Ms. Paulina Bohdanowicz , KTH Institute, Sweden)
1
Biofuels as
  energy
  source
• CO2-neutral –
  photosynthesis:
{CH2O} + O2 =>
  CO2 + H2O

Combustion:
{CH2O} + O2 =>
  CO2 + H2O +
  energy
     Pathways for production of biofuels

                                                     Motor vehicles,
                                        Alcohol
                    Biological conv.   fuels         H2 fuel for fuel
                                                     cell

                                                     Cooking
                                          Biogas
                                                     Heating
    Wood, energy               Direct combustion
    crops, waste,                                    Steam generation
      dung etc.                          Syngas      Electricity generation

                          Thermal                    H2 fuel for fuel cell
                             conv.
                                         Gasoline    Motor vehicles


     Micro-           Chemical conv.
    algae and                           Bio-diesel   Motor
     oilseed                                         vehicles
      crops

3
    Potential causes of concern associated with
                 biomass/biofuels
• LAND
   – Land use conflict - fertile land is used based on cash
     oriented use, cash crops for export or food production.
     Pressure on farmers to cut down forest and cultivate
     virgin soil
   – Deforestation - local wood extraction exceeds local
     production also due to land clearance
   – Desertification - when forest are cut down and the
     surface of the ground is exposed. Evapotranspiration
     increases and the soil dries
   – Erosion - gradual wearing away of land by water and
     wind
   – Visual impact
   – Reduction in biological diversity
   – Typically high input of energy required (fertilisers,
     harvesting processing)
   Source: Boyle et al. 2003; Baguant J., Life Cycle Assessment of Sugar Cane Bioenergy Systems for
   Electricity Production, PROSI Magazine – Jan. 1998 – No. 348 – Research, online paper available at
                                                   http://www.prosi.net/mag98/348jan/energ348.htm
                                 Cut down
    Typical native
    Chilean forest




                     Clearance




5
  New plantation          Desertification : more surface
                          exposed. Evapotranspiration




Even worst: a
cheaper way        Burning of virgin
                   forest.
No need to cut
down the trees,
No
transportation
needed,
Less man power.
          Potential causes of concern associated
                  with biomass/biofuels


    • New agricultural land, less retention of water in
      soil, desertification (higher evapotranspiration)
    • Use of scarce water
    • Improper irrigation of energy crops => soil
      salinity
    • Ground water pollution due to fertilisers
    • H2O for biogas production and distilleries =>
      production of waste water rich in N2,
      phosphorous and potassium. These nutrients
      stimulate the growth of plant – eutrophication
      (depletion of O2 in lakes and rivers)
                                     Source: Boyle et al. 2003; Baguant 1998
7
        Potential causes of concern associated
                with biomass/biofuels
    • Local effects - indoor pollution (biomass for heating)

    • Regional effects - the main pollutants, SO2 and NOx.
      Soil and water acidification, damage to fish
      population, degradation of plants, effects on human
      respiratory function.

    • Global effects: emissions of GHG
       – sugar cane bio-energy systems like the bagasse to
         electricity fuel chain are in fact net emitters of CO2
       – but compared to coal used for power generation, the
         avoided CO2 (i.e. not emitted to the atmosphere) with
         sugar cane biomass can vary between 0.96 kg CO2/kWh
         and 1.10 kg/kWh


                                        Source: Boyle et al. 2003; Baguant 1998
8
          Potential causes of concern associated
                  with biomass/biofuels
    Most of biofuels in developing countries are used
    in households, having a more direct impact.
• Respiratory infections
• Chronic obstrction lung diseases
• Low birth     Particulate Exposures in Developing Countries
  weights                   70

                            60

• Cancer                    50


• Eye              Exposure 40
                    (GEE)*

  problems
                            30
                            20

                                 10
                                  0
                                       Rural    Rural     Urban    Urban
                                      indoor   outdoor   indoor   outdoor
              GEE is the Global exposure equivalent, based on the pollutants concentration and the
                                       hours of exposed to the pollutant
                                                           Source: Boyle et al. 2003; Baguant 1998
9
     Only production and combustion
       of biofules on a sustainable
           basis is CO2-neutral



10
            Positive impacts of biofuels
                  as energy source
• Reduction of greenhouse gas (GHG)
  emissions along with odor by landfill gas
  extraction for bioenergy
• Reduction of NOx emissions
• Reduction of sulphur oxides emissions
    – using biomass for 5% of a coal-fired power
      plant’s heat input would reduce SO2 emissions
      by aprrox. 5%
• Avoided emissions & landfill requirements
  by municipal solid waste combustion (MSWC)
  technology

    Source: EREN, Renewable Electricity
                   from Plant Material,
BIOPOWER, Department of Energy, 2002
            Positive impacts of biofuels
                  as energy source
• Provision of clean gas (biogas) for cooking,
  heating etc.
• Biomass energy crops can improve water & soil
  quality and also improve biodiversity
• Some energy crops can be used
  for the treatment of wastewater
• Reduction of water pollution by animal waste,
  fertilisers and pesticides
• Job creation/rural development



    Source: EREN, Renewable Electricity
                   from Plant Material,
BIOPOWER, Department of Energy, 2002
          Positive impacts of biofuels
                as energy source
     • According to EPA
       estimation, cars burning
       pure methanol & ethanol
       can reduce VOC emissions
       from the tailpipe by 85 to
       95%, while CO emissions
       by 30 to 90%
     • Both methanol & ethanol
       are likely to be key                    Cumulative CO2 benefits of
       hydrogen fuels for fuel                 ethanol compared to RFG in 2010
       cells.                                  (NREL)

                   Bioenergy Information Network (BIN), A gateway to information about fast
                   growing trees, grasses and residues for fuels and power, online publications,
                                                            last updated 08.02.02 available at
                                        http://bioenergy.ornl.gov/doeofd/biowin/stratgy.html
13
    GHG emission intensities for selected fuels,
               g CO2/kWh electric
Conventional 960-1300                   Biomass         37-166
coal
Advanced     800-850                    Photovoltaic    30-150
coal
Oil          690-870                    Hydroelectric   2-410

Gas                         460-1230    Wind            11-75
                            (220 CHP)
Nuclear                       9-100

Source: Boyle et al. 2003
                Costs of electricity with and
                   without external costs

Electricity Source    Generating Costs1     External Costs2         Total Costs


                                        (cents per kilowatt-hour)
Coal/lignite               4.3–4.8                2–15               6.3–19.8
Natural gas (new)          3.4–5.0                 1–4                4.4–9.0
Nuclear                     10–14                0.2–0.7             10.2–14.7
Biomass                      7–9                   1–3                 8–12
Hydropower                 2.4–7.7                 0–1                2.4–8.7
Photovoltaics               25–50                  0.6              25.6–50.6
Wind                         4–6               0.05–0.25            4.05–6.25


1For the United States and Europe.
2Environmental and health costs for 15 countries in Europe.

Source: Worldwatch Institute, State of the world 2003.
15
                Energy & Employment
     Germany: wind energy has a share of around 5 % of
       electricity generation and employs ~ 100,000 people,
       whereas nuclear power supplies 30 % of the electricity
       and employs only 38,000 people [Jochen Twele,
       Windenergie – Technik & Repowering, BWE, Berlin 2002.]




Source: Jochen Twele, Windenergie – Technik & Repowering, BWE, Berlin 2002
16
           Other major environmental problems

     •   Water
     •   Waste
     •   Chemicals
     •   Consumerism…




17
                          Water availability,
                     in 1000 m3/inhabitant/year




Catastrophically
low–      < 1,
Very low –
      1 to 2,
Low –           > 2 to 5,
Medium –             > 5 to 10, High –   > 10 to 20, Very high –   > 20
Source: UNEP, 2002
18
    Selected
      water
    stressed
    countries




      Effluent from water desalination plant, Kuwait
Source: WCD 2000
19
                        Water pollution




     Effluent from water desalination plant, Kuwait
20
                           Consumerism
     • How much does one own?
     • How much of the things one has – one does
       not need
     • How much of the things one actually needs –
       one cannot find


     September 12, 2001, vice president Cheyenne:

      “If you are patriotic – go and buy something
                        American”
21
           Waste generation/disposal

     • History
     • Current status                                    Waste generated annually in fuel
                          million tonnes / GWe           preparation and plant operation
     • Mechanism               0,8

                               0,7

                               0,6


     • Impacts                 0,5

                               0,4

     • Mitigation              0,3


       – No disposal of
                               0,2


         power plant
                               0,1

                                 0
         waste law                     Coal        Oil         Gas        Wood        Nuclear      Solar PV

                                     Ash   FGD waste   Gas sweetening waste   Radioactive waste   Toxic waste




22
     Waste generation/disposal




23   Source: EEA 2003
     Waste generation/disposal




24                     Source: EEA 2003
         Waste generation/disposal




     Waste dump, Mexico
25
                        Soil degradation




26   Source: EEA 2003
                     Conclusion
     • All energy sources and methods of
       conversion have environmental impacts
     • Fossil fuels have the highest impacts, but
       RETs are not environmentally neutral
       either
     • Nevertheless if externalities were
       included in energy costs – RETs would
       prove to be cheaper than conventional
       sources


27
                     Conclusion
     • …and in order to achieve long term
       sustainability of human civilisation a shift
       to renewables is necessary
     • Additionally, most of the renewables are
       available in developing countries and could
       be used to allow ”leap frogging”
       development of these countires
       (instead of transferring dirty technologies
       of industrialized world)

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