Simple wind-diesel concept with high wind penetration in Cape Verde

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Simple wind-diesel conceptwith high wind
penetrationin Cape Verde

• Per Nørgård, Risø DTU, Denmark, pern_at_risoe.dtu.dk
• João Fonseca, Electra, Cabo Verde,
  j.fonseca_at_electra.cv

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Cabo Verde

• Independent (from Portugal) in 1955
• Population 500 000 at 10 islands
• Islands in study
• Santiago
• São Vicente
• Sal
• (Boa Vista)

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Cabo Verde

• Risø DTU as Technical Consultant
• for InfraCo (international project developer)
• in collaboration with Electra (local power
  utility company)

• Power generation based on diesel generation
• Excellent wind conditions
• High average wind speeds most of the year
• Very constant wind
• Low extreme wind speed

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Growing demand
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IPSYSan energy system simulation tool

• Characteristics
• Semi-static time series simulation (minutes time
  steps)
• Includes storage and memory functionalities
• Designed for mixed energy systems
• Performs energy balances and load flow analysis
  (power systems)
• Handles advanced and distributed control
• Developed by Risø DTU

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Simplified single line diagrams
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Operation strategy

1. Minimum continuous diesel load
2. Minimum instantaneous diesel load
3. Minimum spinning reserve diesel capacity
4. Minimum diesel capacity
5. Minimum number of diesel generator units
6. Minimum diesel operation time

• Minimum continuous load of the diesel engines
  30 (optional 50).
• To prevent the diesel engines from sooting up at
  low load.
• The wind power generation may be limited to
  fulfil this condition.

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Operation strategy

1. Minimum continuous diesel load
2. Minimum instantaneous diesel load
3. Minimum spinning reserve diesel capacity
4. Minimum diesel capacity
5. Minimum number of diesel generator units
6. Minimum diesel operation time

• Minimum instantaneous load of the diesel engines
  10.
• To prevent for negative load of the diesel
  generators.

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Operation strategy

1. Minimum continuous diesel load
2. Minimum instantaneous diesel load
3. Minimum spinning reserve diesel capacity
4. Minimum diesel capacity
5. Minimum number of diesel generator units
6. Minimum diesel operation time

• Minimum spinning reserve diesel capacity
  connected to the grid
• 200 of the observed fluctuation of the diesel
  load within the last hour and
• minimum 50 of the actual diesel load (if
  possible).
• To be prepared for the fluctuations in the wind
  power and in the load.

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Operation strategy

1. Minimum continuous diesel load
2. Minimum instantaneous diesel load
3. Minimum spinning reserve diesel capacity
4. Minimum diesel capacity
5. Minimum number of diesel generator units
6. Minimum diesel operation time

• Minimum diesel capacity connected to the grid
• 2 times the wind capacity connected to the grid.
• To ensure dynamic stability of the system.
• _at_ low load high wind
• wind turbines are shut down
• -gt diesel generators shut down

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Operation strategy

1. Minimum continuous diesel load
2. Minimum instantaneous diesel load
3. Minimum spinning reserve diesel capacity
4. Minimum diesel capacity
5. Minimum number of diesel generator units
6. Minimum diesel operation time

• Minimum number of diesel generator units
  connected to the grid
• 2
• Not to rely on a single diesel generator unit.

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Operation strategy

1. Minimum continuous diesel load
2. Minimum instantaneous diesel load
3. Minimum spinning reserve diesel capacity
4. Minimum diesel capacity
5. Minimum number of diesel generator units
6. Minimum diesel operation time

• Minimum operation time of a diesel engine
• 4 hours.
• To limit the number of start / stop of the diesel
  engines.

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Load profiles(3x3 days)
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Seasonal variation of wind
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IPSYS results (Sao Vicente)
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Summary of results
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Not utilised wind energy
1 p.u. 20 wind energy penetration
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Avoided diesel fuel
1 p.u. 20 wind energy penetration
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Minimum diesel load (2012)
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PPA Power Purchase Agreement

• Minimum wind energy leveltake pay _at_ high
  tariff
• Motivates wind power operatorto maximise
  production

• Additional wind energy_at_ low tariff
• Motivates diesel operatorto optimise operation

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Conclusions

• The most critical operation parameter is the
  minimum diesel load.
• Even at 40 wind energy penetration, the not
  utilised wind energy is only 10.
• 20 overinvestment in wind power capacity is
  proposed
• 22 MW -gt 28 MW -gt 0..10 not utilised wind
  energy.
• This seems economically feasible at 5 reduced
  generation cost (/kWh), with the expected demand
  growth.

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Thanks!Seeing you atStand 2463 (Hall 2)
Hall 2

• Per Nørgård
• Risø DTU, Denmark
• pern_at_risoe.dtu.dk