OPTIMISATION OF OPERATIONS FOR ONSHORE AND OFFSHORE WIND FARMS

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OPTIMISATION OF OPERATIONS FOR ONSHORE AND
OFFSHORE WIND FARMS
EWEC 2006, Athens, 1 March 2006 Colin Morgan
ltcolin.morgan_at_garradhassan.comgt
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Optimisation?
Onshore 97 30k/machine/annum (typical!)

• Of what?
• Availability
• Cost of OM

Offshore ? ?
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Onshore OM costs

• OM costs have weak influence on project
  economics
• NPV approx. 10 of CAPEX
• But represent a high proportion of operational
  cashflows
• Decision-driver on retrofits in-house
  servicing re-powering

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The offshore differences ..
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The offshore differences ..
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The offshore differences ..
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O2M Structure
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Outputs

• Availability
• Production and Lost Production
• Costs, resource and spares usage

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Example Wind Farm (onshore / offshore)

• 100 x 3MW units
• Representative assumptions on
• Unit costs
• Revenue assumptions
• Failure / alarm shutdown profiles
• Offshore and onshore made as comparable as
  possible
• OM crewing optimised in both situations to give
  minimum OM cost
• Offshore-specific
• Wave climate moderate (long-term Hs 1.29m)
• Access limit Hs lt 1.5m
• Transit time to site 2hrs (including
  mobilisation etc)

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Findings - costs
Offshore vs. onshore Sensitivity of cost to
failures
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Findings - downtime
Offshore vs. onshore Sensitivity of availability
to failures Serial failure situation not
modelled Value of warranty
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Summarising

• Onshore OM
• Worth more attention than it often gets but
  experience and trial and error can lead to
  reasonable optimisation of any given project or
  portfolio
• Offshore OM
• Shortage of relevant project experience
• Much reduced scope for trial and error
• Higher stakes
• Common factor is turbine reliability