Wind energy

Energy Centre summer school in Energy Economics 12-14 April 2021 Le Wen [email protected] Outline

The technology

Wind energy in the world

Wind research at the Energy Centre The technology calculation

pA 1 ***3 wind 2 2 A   * D Swept area of Blades (A)  2

Rotor Diameter (D) -Effect of air density, ρ (kg/m3 ) -Effect of swept area, A (m2 ) -Effect of wind speed, v (m/s) Wind turbine power curve Capacity factor

푡ℎ푒 푡표푡푎푙 푎푚표푢푛푡 표푓 푒푛푒푟푔푦 푝푟표푑푢푐푒푑 푑푢푟𝑖푛푔 푎 푝푒푟𝑖표푑 표푓 푡𝑖푚푒 cf = 푡ℎ푒 푎푚표푛푡 표푓 푒푛푒푟푔푦 푝푟표푑푢푐푒푑 푎푡 푓푢푙푙 푐푎푝푎푐𝑖푡푦

푎푐푡푢푎푙 푒푛푒푟푔푦 푔푒푛푒푟푎푡푒푑 (푀푊ℎ) cf = 푐푎푝푎푐𝑖푡푦 푀푊 ∗ 푡𝑖푚푒 푝푒푟𝑖표푑 (ℎ) Wind resource in New Zealand

YEAR Installed capacity MW)Generation(GWH) Capacity factor

2015 689 1914 ?

2014 682 1946 ?

2013 621 1865 ?

2012 621 1895 ?

2011 621 1824 ? 푎푐푡푢푎푙 푒푛푒푟푔푦 푔푒푛푒푟푎푡푒푑 (푀푊ℎ) cf = 푐푎푝푎푐𝑖푡푦 푀푊 ∗ 푡𝑖푚푒 푝푒푟𝑖표푑 (ℎ)

For example: capacity factor2015=(1914*1000)/(689*365*24)=0.3251 Source: Freeman Media Ltd, 2016. Wind resource in New Zealand

YEAR Installed capacity MW)Generation(GWH) Capacity factor

2015 689 1914 0.3251

2014 682 1946 0.3340

2013 621 1865 0.3515

2012 621 1895 0.3572

2011 621 1824 0.3438

For example: capacity factor2015=(1914*1000)/(689*365*24)=0.3251

Source: Freeman Media Ltd, 2016. Wind resource in New Zealand Hourly Average Wind Speed 2005-2007

14

13

12

11

10

9

8

7 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223 2005 2006 2007

Average of MWT1 Average of CKS1 Average of NTH1 Average of CNI2 Average of STH2 Average of STH3

Self-elaboration. Date source: NIWA (Jan 2005 to Dec 2007) Wind energy in the world Historical milestones I

Middle Ages • Iran (by 7th to 9th century): grinding corn and pumping water • Middle East, Central Asia, , India, Sicily (by 1000 AD): seawater pumping for making salt • North-western Europe (1180s on): grinding flour 19th century • Denmark, by 1900: 2500 windmills (30 MW) for mechanical loads such as pumps, and mills. • American Midwest, 1850-1900: 6 million small windmills for irrigation • Scotland, 1887: Prof James Blyth built the first windmill for production on electricity, used for providing lighting in his holiday cottage • Ohio, 1888: Charles F. Brush’s 17m rotor diameter, 144 blades, wind turbine, 12 kW, used to charge batteries or operate up to 100 (inefficient!) light bulbs Historical milestones II

20th century • 1901-1973: wind generators widespread, but competed against fossil fuel plants and centrally generated electricity • USSR, 1931: 100kW, 30m diameter (d) • UK, early 1950s: 100kW, 24m (d) • Denmark, 1956: 200kW, 24m (d) • France, 1963: 1.1MW, 35m (d) • 1973-onwards: oil price crisis spurred investigation of non- petroleum energy sources • USA, 1980s: Total US installed wind power capacity is 10MW, for 8,575 homes. • USA, 1981: 3MW horizontal axis, hydraulic transmission instead of yaw drive • USA, 1987: 3.2MW, the first large-scale variable speed drive train and a two-blade rotor. • Canada, 1984: 4MW Darrieus wind turbine • Large turbines constructed with 1, 2 or 3 blades (prototypes) • Smaller, often simpler turbines available for commercial sale Modern wind turbines The Danish concept: • 3-bladed, stall-regulated rotor, fixed speed became dominant model in 1980s, less than 200kW rated power More recent developments: • 2-3MW(3-8MW)/97-117m(112-164m) diameter onshore (offshore) • Rotor speed: Fixed speed / Variable speed • Blade control: Full-span control of the blades (pitch regulated) • Advanced materials: blades lighter -> can be made longer • Drive train: Direct-drive concept vs. gearbox + high speed generator World’s largest wind farms (onshore) • The Project  base (7,965 MW). The project is one of six national wind power megaprojects approved by the Chinese government. It is expected to grow to 20,000 MW (20 GW) with 7,000 wind turbines. The first phase of the wind farm with 5.16GW, 3500 turbines was completed in Nov 2010. Offshore technologies

• Existing foundation types  Monopoles (a single cylindrical structure- e.g.the London Array)  Jackets (a series of cylindrical tubes-e.g. the Alpha Ventus wind farm located off the coast of Germany) • Emerging foundation solutions  Floating foundations ― tension-leg-platforms ― semi-submersible ― spar buoys • Main issues for offshore wind power  Going deeper, farther from coast – foundations & interconnections  Reliability – high cost of maintenance!  Need for mainstreaming installation processes (currently few specialised vessels) World’s largest wind farms (offshore) Hornsea 1 (1,218 MW) - 2019 (25-30 meters) • The largest offshore wind farm in the world • In the North Sea off the coast of England • 174 Siemens SWT-7.0-154 • The first turbine began supplying power to national grid in Feb 2019 • One million homes • The farm is planned to have a total capacity of up to 6GW. Hywind Scotland: world’s first floating wind farm – 5 floating turbines, 30 MW (more than 90 meters) • Is the world’s first commercial wind farm using floating wind turbines, • Situated 19 km off Peterhead, Scotland. • The farm has five 6 MW Hywind floating turbines with a total capacity of 30 MW. • Capacity factor is over 50%. • Hywind Scotland was commissioned in October 2017. Hywind Scotland: world’s first floating wind farm – 5 floating turbines, 30 MW (more than 90 meters) • Is the world’s first commercial wind farm using floating wind turbines, • Situated 19 km off Peterhead, Scotland. • The farm has five 6 MW Hywind floating turbines with a total capacity of 30 MW. • Capacity factor is over 50%. • Hywind Scotland was commissioned in October 2017. LCOE from utility-scale renewable power generation technologies, 2010 and 2019

Source: IRENA, 2020. Wind turbine price indices and price trends Global weighted average total installed costs, capacity factors, and LCOE for onshore wind, 2010-2019

Source: IRENA, 2020. Global weighted average total installed costs, capacity factors, and LCOE for offshore wind, 2010-2019

Source: IRENA, 2020. Wind power capacity and annual additions, 2009-2019, in the world

Wind power capacity and additions, top 10 countries, 2019

Source: REN21, 2020 Offshore wind energy, 2009-2019, in the world

Source: REN21, 2020 Wind power in the electricity mix, 2019

Source: REN21, 2020 Global Investment in Renewable by Technology, 2019 Wind research at the Energy Centre Research on wind development feasibility studies at the Energy Centre

Well-suited during Suitable for Well correlated with NI months of low SI balancing SI demand (& NTHs, hydro hydro in CNIs with prices!) general Research on wind development feasibility studies at the Energy Centre 100% renewable electricity

• Government target: • 100% from renewables by 2030 • Generation profile: • Hydro dominated ~ 60% depending on water inflows • Wind generation contributes 5-6% • Geothermal 18% • Thermal ~ 15-19% • NZWEA target: • 20% wind energy by 2030, 2400 MW consented

31 Wind energy expansion

Hours of day

32 Average wholesale price effects of an increase of 10% in wind

33 What happens to wholesale price if there is a 10% increase in wind generation at BPE (Bunnythorpe) ?

-$0.13 -$0.13 -$0.19 -$0.27

-$0.32

-$0.32 -$0.22

-$0.14

-$0.12 34 -$0.11 Where is best place to build wind farm?

Estimated net annual savings (million $) per MW installed LRMC ($82/MWh)

1MW

-$0.61 mil

-$0.59 mil $2.79 mil

$8.44 mil

-$0.32 mil

$0.77 mil -$0.44 mil $1.79 mil

Wen, L., Sharp, B., & Sbai, E. (2020). Spatial Effects of Wind Penetration and its Implication for Wind Farm Investment Decisions in New Zealand. The Energy Journal. 41(2). PP. 47-72.

-$0.19 mil

35 -$0.66 mil Discussion • Results show that private investment in additional wind capacity leads to positive gains in economic value. • However, it’s not clear if private investment is financially profitable. Investing in capacity at a given node can reduce the return to a generator’s assets in the network. • Reaching the goal of 20% electricity from wind generation depends on growth in demand. Maybe, this can come about from growth in electrification of transport.

36 Here’s the challenge

Supply Demand

• Target 100% • Economic structure • Geothermal base load • Services • Limited access to new ? • Manufacturing • Residential conventional hydro = • Transition to low carbon • 2400MW wind potential • EVs • Buses …“what if wind not blowing & dry season?”

37 Research on wind development feasibility studies at the Energy Centre

Can hydro and wind be a good combination to stabilize the electricity price? A seasonal spatial econometric analysis in New Zealand

Exploring the complementarity of hydro and wind

+ Wholesale price is affected by wet/dry season

140 2011 dry 140 2011 wet 120 120 ($/MWh) 2012 wet 2012 dry 100 100

80 80

spring

summer 60 60

40 2011 40 2011 2012 2012 20 20 BPE HAY HLY HWB OTA ROX TIW TKU TWZ WKM BPE HAY HLY HWB OTA ROX TIW TKU TWZ WKM

140 140 2011 2011 2011 wet 2012 120 2012 120 ($/MWh) 2012 dry 100 100 80 2011 wet 80

winter

autumn 60 2012 dry 60

40 40

20 20 BPE HAY HLY HWB OTA ROX TIW TKU TWZ WKM BPE HAY HLY HWB OTA ROX TIW TKU TWZ WKM

39 Wholesale Prices, Wind and Thermal Generation at HLY (Huntly)

Low wind & high hydro 20 price ($/MWh) 4 Jan 2012,Wed 380 80 wind (MW) 18 thermal (MW) 16 360

) 14 340 60 12 320 10 $/MWh 300

( 40 8 280 6 price price 260 20 4 2 240 0 220 0 0 2 4 6 8 10 12 14 16 18 20 22 24

40 Wholesale Prices, Wind and Thermal Generation at HLY (Huntly)

High wind & low hydro 100 22 Mar 2012,Thu 50 800 95 45 90 40 700 price($/MWh) 85 wind(MW) 35 thermal(MW) 600 80 30 75 25 500 20 price ($/MWh) price 70 400 15 65 10 60 300 5 0 2 4 6 8 10 12 14 16 18 20 22 24 hours of day

41 Research Questions

1. Is increased wind generation associated with lower wholesale prices and higher wholesale price volatility? 2. Do wholesale prices increase during periods of low hydro storage and are they associated with increased thermal generation? 3. Does hydro availability during wet seasons mitigate price volatility due to increased wind generation?

42 Q1&Q2: Total Effects of Wholesale Price

2011 2012 0.12*** 0.23*** load

0.85*** 2.15*** thermal/load

-3.27*** -9.74*** hydro/load

-16.41*** -18.85*** wind/load

-20 -15 -10 -5 0 -20 -15 -10 -5 0 2011 2012

*** indicates 1% level of significance.

43 Q1&Q3: Variability of price

Seasonal price effects of a 10% increase in wind 12 spring(dry) 9.84 (%) 9 summer(wet) autumn(wet) 7.09 7.04 6 winter(wet)

3 (N.S) 0.37 2011 0 -0.09 -3 -1.51 (N.S) -1.82 -2.01

9 spring(wet) summer(dry) (%) 6 autumn(dry) 5.24 winter(dry) 3.60 3 0.75 0.70 2012 0 -0.56 -0.48 -3 -1.49 -3.05 Price change Price variance change Note: N.S indicates that coefficient is not significant (price volatility) 44 Summary of Results

• Increased wind generation is associated with lower wholesale prices and higher wholesale price volatility. • Wholesale prices increase during periods of low hydro storage and are associated with increased thermal generation. • Hydro availability during wet seasons can mitigate price volatility due to increased wind generation.

45 Lake Onslow

Formed in 1890 by the damming of the Teviot River and Dismal Swamp.

46 Pumped hydro storage? • NZ Battery project Phase 1 Business case (2021) – investigation & evaluation ($30 m) Phase 2 (2022) – engineering design & field work ($70 m) Phase 3 (2022-2026) – construction • Further development of wind can contribute to renewables target • BUT evidence suggests an increase in price volatility • Lake Onslow offers an option to meet anticipated growth in demand and moderate price volatility. • Is it economic? – we need the business case.

47 Research on wind development feasibility studies at the Energy Centre

• On-going research: Optimal Allocation of New Zealand Wind Generation

With Matthew Brunt and Stephen Poletti This study uses an agent-based electricity pricing model to evaluate existing and potential wind farms by taking into account wind capacity, wind distribution, wind output variability, and electricity price, and to allocate optimal wind sites. B Thank you for your attention!

Dr Le Wen [email protected] 49