The Coming Power of Wind: Perspectives and Prospects Soirée Technique, Dec 8th Session 4: Renewable Energy Sources Presented by Dr. Barry Rawn Delft University of Technology Thank Simon. Observe wind power is external driver that makes power engineering exciting. Why? Because its differences make us revisit the basic assumptions of our systems.

Prospects: Perspectives: This talk is about: substantial helpful 1 This talk is about: Prospects: substantial helpful effect on climate major component of energy security .. they are different. long term price stability re-think way we run power system Perspectives: The myths. Neither impossible nor difficult: just different. policy makers and lawyers investors ..they are many. electricity grid and market operators

“stabilization triangle” substantial helpful effect on climate 2 Global: the “stabilization triangle” substantial helpful effect on climate European level: About 25-30% of efforts Image credit: cmi.princeton.edu Two things: think in GT, and consider possibilities of existing technology 200 Gt, in next 50 years: Each wedge: GT/year Install 2TW of wind; provide about 5 PWh

We’re coupling our energy system to climate patterns, and to 3 We’re coupling our energy system to climate patterns, and to weather patterns. Variable, but predictable. Regional-but renewable Image credit: The Atmosphere, 8th edition, Lutgens and Tarbuck, 8th edition, 2001

Will climate change affect wind power projects? 4 Will climate change affect wind power projects? Michelangeli and Loukos, 2007 Rough reasoning anticipates future reduction in yield… ..detailed models confirm. Effect varies over globe; depends on local features; hard to predict. Lorenz and DeWeaver, 2007

Will wind power projects cause climate changes? wind energy conversion requires momentum transfer. 1 .tradeoff, slow down 2. corkscrew-> mikxing 5

Will wind power projects cause climate changes? Wake effect: 6 Will wind power projects cause climate changes? Brand 2009 minimum safe distance (2-10% deficit): order of tens of kilometers the recovery distance (1% Deficit): hundreds of kilometers. Christiansen and Hasager 2005 Wake effect: becoming of legal interest Brand 2009

Will wind power projects cause climate changes? 7 Will wind power projects cause climate changes? Keith, 2004 Change global mean temperature? Detectable but negligible compared to anthropogenic forcing. Takel, 2011 Wind power affects crops, local weather? First indication: helpful or neutral; but research just starting

Is there even that much wind power? 8 Is there even that much wind power? Physical Potential Technical Potential Economic Potential Hoogwijk 2004

Is there even that much wind power? 9 Is there even that much wind power? Technical: 96 PWh/year, Economic: 53 PWh/year at 0.13 €/kWh 21 PWhr/year at 0.052 €/kWh versus 15 PWh/year global electricity consumption of global electricity consumption Hoogwijk 2004

Is there even that much wind power? 10 Is there even that much wind power? Many regions have resource exceeding consumption, costs differ. Hoogwijk 2004 3 PWh/year European electricity consumption in 2008:

Is there enough money to build it all? 11 How much has been built? As of 2004, about 0.05% of the economic potential was developed As of 2010: perhaps 0.4%. Source: GWEC Growth rate of last 5 years: ~27% (doubles every ~3 years) Is there enough money to build it all? Exponential growth: it’s an outcome Global: 0.5T USD a year to meet 450 PPM (vs bond market 90 T USD) Europe: to meet EU targets, 30-65 billion a year (vs bond market 23 T, GDP of Europe: 16T) Trend in pension fund investment in infrastructure: estimated at 1 T a year

Addressing investment risk: significant deployment barrier 12 Addressing investment risk: significant deployment barrier Samec 2011 Sources of risk: resource uncertainty, inflation, construction delay Mitigation instruments: wind derivatives, loan guarantees, construction insurance

Generation mix: limits and changes in thinking 13 Generation mix: limits and changes in thinking 30% renewable energy scenario studied in North America: (image credits NREL) Total system load: wind coal nuclear Inflexible generation can impose minimum generation limit: Storage or transmission needed to avoid curtailment “Cycling” of units uncomfortable; Need emerges for new types

Variability and Uncertainty 14 Variability and Uncertainty Provision always existed for changes: both anticipated and unexpected. Image credit:Makarov et al, PNNL-19189, 2010 Madsen and Pinson: imm.dtu.dk, 2009 This applies to “msot of the time” Wind power forecasts a common tool in control rooms.

controllable wind power, because forecasts not 15 Example: Denmark First to pioneer controllable wind power, because forecasts not perfect. Image credit: upwind.eu “Soft Storm Transition” or “Storm Control”: Farm-level control using pitch Wind speed (m/s) Power production (MW) 0 minutes 2 Image credit: upwind.eu Image credit: Gijs van Kuik, TU Delft, DUWIND

16 Example: Denmark Image credit: Energinet

Switched Power Electronics Interfaces 17 Switched Power Electronics Interfaces Synchronous Machine (traditional) simple, fixed, strong Power Electronic Interface Complex, flexible, relatively fragile

Example: Ireland 18 An island electric power system Must be mostly self-sufficient, even for short periods Contingency event: Loss of big generator, or introduction of big load Hirvonen 2003 In first instances: Need to use energy stored in system’s rotating masses

70-80% Example: System Ireland collapses 60-70% immediately System 19 70-80% System collapses immediately Example: Ireland 60-70% System splits in half, collapses. 2008/2009 range of operation Wind turbine rotors not forced to be synchronous: -> several related problems Eirgrid, All-Island TSO Facilitation of Renewables Studies, Final Study Report

20 Example: Spain Electricity grid behaviour during a fault (lightening, tree, etc) generators can help by staying connected, in spite of voltage transient: formerly allowed disconnect level new requirement typical transient Image credit: RED Eléctrica España Bömer 2011

21 Example: Spain Wind power production behaviour *before* “ride-through” requirement: nuclear sized dips. Image credit: RED Eléctrica España How are the worst situations avoided?

22 !  Image credit: RED Eléctrica España

Wrapping up: From all these perspectives, which ideas to take home ? 23 Wrapping up: From all these perspectives, which ideas to take home ? We’re coupling our energy system to the climate in a new way. Variability and uncertainty in our power system: not a new thing, but changes can be expected Imp notes: Own animal: -converter interface: relatively fragile; excellent control -within available resource: extremely flexible -composition of many units can cause complexity, but also brings robustness. - Generation is always a mixture; wind power plants their own animal offering challenges but also benefits