GUJARAT ENERGY TRANSMISSION CORPORATION LIMITED

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• GUJARAT ENERGY TRANSMISSION CORPORATION LIMITED
• Grid related issues in case of Wind/Solar
• based Generation in Gujarat
• 07th February, 2009
• S. K. Negi
• Managing Director

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Power Scenario in Gujarat as on 31.12.2008

• Present power generating capacity including State
  sector, Private sector Share from Central
  sector 10417 MW.

• 56 is generated from South Gujarat.
• 37 is generated from Central Gujarat.
• 7 is generated from Saurashtra and Kutch area.

• Out of total 10417 MW installed capacity, 63 is
  from thermal, 23 is from Gas, 7 from hydro and
  7 from nuclear sources.

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Future Power Scenario in Gujarat

• 52 is generated from South Gujarat.
• 31 is generated from Central Gujarat.
• 27 is generated from Saurashtra and Kutch area.
• 4000 MW Mundra, UMPP is also located at Mundra in
  Dist Kutch.

• Out of total 19934 MW installed capacity, 67 is
  from thermal, 26 is from Gas, 4 from hydro and
  3 from nuclear sources.

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Power Scenario in Kutch and Saurashtra

• Present installed capacity of Saurashtra and
  Kutch is as under
• KLTPS, Panandhro, Kutch - 215 MW
• GMDC, Akrimota, Kutch - 250 MW
• GSECL, Sikka, Saurashtra - 240 MW
• Total. - 705 MW
• Proposed anticipated capacity addition in
  Saurashtra and Kutch during 11th five year plan
  and subsequent years
• KLTPS, Panandhro, Kutch (Unit-IV) - 75 MW
• Adani Power, Mundra, Kutch - 2640 MW
• UMPP, Mundra, Kutch - 4000 MW
• GSECL, Sikka Extension, Saurashtra - 500 MW
• Essar Power, Vadinar, Saurashtra - 1200 MW
• GPPC, Pipavav, Saurashtra - 700 MW
• BECL, Bhavnagar, Saurashtra - 600 MW
• Total. - 9715 MW
• In addition to this, in Western Gujarat itself
  the approved proposals for integration of Wind
  power are around 3600 MW.

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Power Scenario in Kutch and Saurashtra

• The pending proposals for integration of Wind
  power are around 4000-4500 MW.
• Also, a proposal for establishing concentrated
  solar thermal power project to the tune of 8000
  MW in Kutch is in the conceptual stage.
• To summarise West Gujarat generation more than
  25000 MW of which
• around 10500 MW will be from conventional
  sources and
• more than 14500 MW from renewable energy sources.
  
• West Gujarat alone cannot absorb this huge
  quantum of power or it can be rather said that
  the load of entire State may not reach this
  level.
• As per 17th Electric Power Survey, published by
  Central Electricity Authority, New Delhi,
  projected load of Gujarat State is 14374 MW by
  March-2012.

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Amendment in Wind Farm Policy 2007

• The Government of Gujarat through GR No WND
  1120082321B dated 7th January 2009, has made
  amendments in the Wind Power Policy 2007
  notified earlier through GR No EDA-102001-3054-B
  dated 13th June 2007 .
• Wheeling of power to consumption site at 66 KV
  voltage level and above-
• The wheeling of electricity generated from the
  Wind Turbine Generators (WTGs), to the desired
  location(s) within the State, shall be allowed on
  payment of transmission charges, and transmission
  losses otherwise applicable to normal Open Access
  Customer.
• Wheeling of power to consumption site below 66
  KV voltage level.
• The wheeling of electricity generated from the
  WTGs, to the desired location(s) within the
  State, shall be allowed on payment of
  transmission charges, otherwise applicable to
  normal Open Access Consumer, and transmission and
  wheeling losses _at_ 10 of the energy fed to the
  grid.
• The wheeling of electricity generated by smaller
  investors, having only one WTG in the State, to
  the desired location(s), shall be allowed on
  payment of transmission charges, otherwise
  applicable to normal open access consumer, and
  transmission and wheeling losses _at_7 of the
  energy fed to the grid.
• Wind farm owner desiring to wheel electricity to
  more than two locations shall pay 5 paise per
  unit on energy fed in the grid to concerned
  Distribution Company in whose area, power is
  consumed in addition to above mentioned
  transmission charges and losses, as applicable
• The electricity generated from the WTGs
  commissioned from 1st April, 2009, may be sold to
  GUVNL and/or any Distribution Licensee within the
  state, at a rate of Rs. 3.50 per unit of
  electricity for the entire period of PPA .
• GUVNL and / or any Distribution licensee may
  purchase surplus power from WTGs wheeling power
  for their captive use after adjustment of energy
  against consumption at recipient unit (s) at a
  rate of 85 of tariff applicable to WTGs
  (commissioned in same tariff block) selling power
  to GUVNL and /or any Distribution licensee.
• GETCO is required to erect evacuation facilities
  beyond 100 kms between Wind Farm sub-station to
  GETCO sub-station
• As per the amended Wind Power Policy -2007, GETCO
  is required to collect Bank Guarantee _at_ Rs. 5
  lacs per MW based on allotment of transmission
  capacity and in case the Developer fails to
  achieve Commercial Operation within the one year
  period in case of installed capacity up to 100
  MW, two years in case of installed capacity from
  201 MW to 400 MW and three years in case of
  installed capacity from 401 MW to 600 MW, the
  Bank Guarantee shall be forfeited by GETCO.

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Summary of Wind farms in Gujarat
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Existing Wind farms in Gujarat
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Proposed Wind farms in Gujarat
(Approved and work under progress)
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Contd- Proposed Wind farms in Gujarat
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Proposed Wind farms in Gujarat
Not approved wind farm projects)
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Contd- Proposed Wind farms in Gujarat
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Wind Energy

• Growing concern for the environmental
  degradation has led to the worlds interest in
  renewable energy resources. Wind is commercially
  and operationally the most viable renewable
  energy resource and accordingly, emerging as one
  of the largest source in terms of the renewable
  energy sector.
• Wind is the natural movement of air across the
  land or sea. Wind is caused by uneven heating and
  cooling of the earths surface and by the earths
  rotation. Land and water areas absorb and release
  different amount of heat received from the sun.
  As warm air rises, cooler air rushes in to take
  its place, causing local winds. The rotation of
  the earth changes the direction of the flow of
  air.
• This type of energy harnesses the power of the
  wind to propel the blades of wind turbines. These
  turbines cause the rotation of magnets, which
  creates electricity.

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Wind Energy

• Wind Energy as a source of electricity has
  following advantages
• Wind power produces no water or air pollution
  that can contaminate the environment,
• Power from the wind does not contribute to
  global warming because it does not generate
  greenhouse gases,
• Wind generation is a renewable source of energy,
  which means that we will never run out of it.
  Fuel source is free, abundant and inexhaustible,
• Extremely low operating cost,
• Less commissioning period,
• Creates employment, regional growth and
  innovation,
• Reduces poverty through improved energy access,
• It is very good as a fuel saver.

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Wind Energy

• At the same time, wind has some peculiar
  characteristics
• Wind is unpredictable therefore, wind power is
  not predictably available. When the wind speed
  decreases less electricity is generated. This
  makes wind power unsuitable for base load
  generation.
• Limited control or no control on generation.
• Drastic variation in generation due to variation
  in wind speed.
• (As shown in the graph).
• Electricity produced by wind power sometimes
  fluctuates in voltage and power factor, which can
  cause difficulties in linking its power to a
  utility system.
• Because winds do not blow strongly enough to
  produce power all the time, energy from wind
  machines is considered intermittent, that is,
  it comes and goes. Thus, the average plant load
  factor of wind generators is very low to the tune
  of 15-20. Therefore, utility companies can use
  it for only part of their total energy needs.

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Wind Energy

• The maximum wind generation is available during
  monsoon / off-peak period of the year when the
  total system demand crashes by about 40-50 and
  it becomes very difficult for the load dispatcher
  to handle the system effectively. In other words,
  it can be said that the wind energy is available
  in abundance when not needed and not available
  when needed most.
• Wind energy being green power and excessively
  available in monsoon, the load dispatcher is
  compelled to back down even the cheaper, firm and
  reliable power from thermal and hydro power
  stations.
• Depends upon wind velocity.
• Geographical locations , potential of wind.
• Limited potential area.
• Proximity to the load centre.
• In Gujarat, Kutch Saurashtra are identified has
  a good potential of wind energy.

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Wind Farm Generation for year 2007-08
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Wind Farm Generation for the year 2008-09
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Wind energy variation graph
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Wind energy variation graph
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Wind Generation on 19-11-08
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WIND FARM GENERATION OF 19-11-08 V/S FREQ
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ENERGY FOR 2007
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ENERGY FOR 2008
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Integration with grid

• There are number of unresolved technical,
  institutional and regulatory
• questions concerning distributed generation in
  general and wind
• generation in particular.
• On the technical level, major barriers are..
• Novelty and unfamiliarity of distributed
  technologies.
• Lack of substantial field experience with these
  technologies.
• Costs and complexity associated with thorough
  engineering evaluations.
• Weak evacuations network as well as onward
  transmission networks.
• Less availability of evacuations corridors.
• Less consumptions in local area due to wide
  variation in load due to variable load in
  agriculture, less and variable industrial demand
  and low demand on staggering day.
• Variable local load pattern leads to overloading
  of transformers and main transmission lines which
  requires high capacity of strengthening of
  transmission network.
• Average PLF observed 15-20 which leads to
  inefficient occupation of transformer capacity
  and non utilization of infrastructures.

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Electrical grid

• Electrical power grid is an unique one in which
  generation and demands are balanced
  instantaneously and continuously.
• Fluctuations in power consumed by the consumers
  and variations in uncontrolled generators are
  compensated by the controlled generators.
• When generation equal to load, frequency operates
  at 50 Hz. Variation in frequency indicates rise
  of load or generation vice versa is term as a
  balancing.
• In the grid system, it is not necessary for
  compensating each and every variation from
  individual consumers / generators.
• Only aggregate variation in the control area is
  balanced.
• Aggregation is the powerful tools with the power
  system operators.
• When wind power plants are introduced into the
  power system, an additional source of variation
  is added to the already variable nature of
  system.

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Load-Generation balance

• In large interconnected system, load generation
  is reflected with change in tie line flows.
• In a small system, load generation balance is
  reflected with variation in frequency.
• Variation in frequency is limiting factor for
  capacity addition of the wind farms.
• In predominantly hydro and gas generation system
  with good ramp rate will be positive factor,
  helping for compensating variation of wind
  generation.

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Balancing

• Balancing in power system occurs over wide time
  frames
• Years in advance Enough generation has to be
  planned and built so that there is sufficient
  capacity available to meet load requirements
• Day Ahead Select which available generator can
  reliably meet expected requirements at lowest
  cost.
• Real Time Real time balancing can be obtained
  by two different methodology
• Load Following (Backing down)
• Load Regulation (Load Shedding)

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Balancing by Load Following

• Load following requirement are highly correlated
  .
• 24 hours power supply to rural under JGY scheme.
• 24 hours power supply to urban area.
• 8 hours committed agriculture supply in various
  groups.
• High demand during summer due to domestic
  commercial cooling load.
• High demand agriculture demand during Ravi crop.
• Demand variation due to festival seasons.
• Load demand during morning evening peak.

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Balancing by Load Regulations

• Load Regulation requirement are correlated by.
• Availability of generation on bar.
• Ramping rate of generating stations.
• Variable cost of generating stations.
• Technical Minimum of generating stations.
• Peak and off peak demand, required generation to
  be kept in reserve.
• The random variation in demand OR generation is
  adjusted instantaneously by primary response
  generators.

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Grid operation with Wind Generation

• Scenario 1
• An increase in load along with increase in wind
  generation OR drop in load along with drop of
  wind generation Additional generation required
  for frequency maintenance is less.
• System Operator
• It is a safe operation for grid operators.
• Most favorable condition for grid operators.
• During evening peak, maximum wind energy
  available and it helps to meet peak demand.

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Grid operation with Wind Generation

• Scenario 2(A)
• A drop in load along with increase in wind
  generation.
• System Operator
• Backing down of other generators.
• High Voltage problem and switching off lines.
  System operation with critical loading.
• If local load is very low, overloading of
  associated transmission lines.

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GETCO grid operation with Wind Generation

• Scenario 2(A)
• A drop in load along with increase in wind
  generation .
• System Operator
• When load is very low and wind generation is
  maximum, system operator has to back down cheaper
  generation at Panandhro and Akrimota to control
  loading of 220 KV Sivlakha-Morbi line.
• In case of contingency of tripping of either
  Morbi-Sivlakha OR Anjar-Deodar OR
  Sivlakha-Sankhari lines, total generation at
  Panadhro and Akrimota affected badly.
• In Kutch area, due to high wind energy
  generation, voltage remains high causing frequent
  failure of lines disturbing parameters while
  synchronizing, delaying in synchronization.

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Grid operation with Wind Generation

• Scenario 2(B)
• An increase in load along with drop in wind
  generation .
• System Operator
• Increasing load along with decrease in wind
  generation is a very critical nature of situation
  for system operator.
• Additional generation is to be brought into
  system very quickly.
• If no generation available, heavy load shading
  to be resorted.
• If frequency permits, overdrawl at that
  prevailing rate.
• Requisition of costly generation i.e. on SPOT gas
  , Naphtha if available
• Remedies
• Additional generation capacity is required for
  maintenance of load generation balancing
  especially gas based and hydro based.

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Power Quality with Wind Generation

• Generally it is believed that with increase in
  wind generation, the power quality suffers.
• Main power quality problems are
• Voltage Regulation,
• Harmonics.
• Old WTG machines with induction generators have
  not been required to participate in system
  voltage regulation. Their reactive power demand
  are compensated by switched shunt capacitors.
• New WTG machines with variable frequency drives
  have inherent control of reactive power output
  and can participate in voltage regulation.
• If wind farm is far from generation source, high
  voltage witnessed near to wind farms with
  increase in wind generation.
• The variable frequency generators in WTGs use
  AC-DC converter for connection with Grid, which
  increases the Harmonics level in the system.

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Wind Penetration

• Energy penetration is the ratio of the amount of
  energy delivered from the wind generation to the
  total energy delivered. For example, if 200
  megawatthours (MWh) of wind energy is supplied
  and 1,000 MWh is consumed during the same period,
  winds energy penetration is 20.
• Capacity Penetration is the ratio of the
  nameplate rating of the wind plant capacity to
  the peak load. For example, if a 300-MW wind
  plant is operating in a zone with a 1,000-MW peak
  load, the capacity penetration is 30 . The
  capacity penetration is related to the energy
  penetration by the ratio of the system load
  factor to the wind plant capacity factor. Say
  that the system load factor is 60 and the wind
  plant capacity factor is 40. In this case, and
  with an energy penetration of 20, the capacity
  penetration would be 20 x 0.6/0.4, or 30.
• Instantaneous penetration is the ratio of wind
  plant output to load at a specific point in time,
  or over a short period of time.

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Conclusion

• If the share of wind generation instantaneous
  penetration at any point of time is excessively
  high compared to the total system demand, then,
  following new operating methodology need to be
  adopted for ensuing reliability and stability of
  system
• Methodology for accurate long term short term
  forecasting.
• Real time data from wind farm to system operator
  to be made available for effective grid
  operation.
• Reserve capacity with high ramp up generators
  such as a hydro and gas shall be kept.
• All wind energy generation be brought under
  regulations of ABT which means elimination of
  generation in case of high frequency or system
  constraints.
• Reinforcement of main transmission network and
  power corridors.
• Augmentation and reinforcement of voltage
  regulating equipments such as reactors, switched
  capacitors including FACTS devices.

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Thank you