First published on April 23, 2014 at: http://www.renewablesinternational.net/
, bechabot@wanadoo.fr
The “silent wind power revolution” consisting in the not sufficiently known but proven availability of new wind turbines models optimized to deliver high and very high annual capacity factors including in low and medium wind speed areas has been described in references [1] and [2] and the bright perspectives of the cost competitiveness of their delivered kWh has been analyzed in reference [3].
China has already experienced a drastic change in its onshore wind power market, shifting from the most windy but remote areas to less windy ones being closer to the large energy consumption places and cities, opening very large opportunities for the country and its wind industry to develop and install those new wind turbines models, and so being a major player in the huge domestic and international markets related to this “silent wind power revolution”.
This article summarizes the results of an independent study of the potential impact of the recent availability of a new wind turbine model from the Chinese GOLDWIND Company [4] specifically designed for the low and very low wind speeds areas (IEC4 wind class, from 5 to 6 m/s average annual wind speed at hub height). Here also, there is evidence that the recent shift to a specific wind turbine model with a very high ratio Su between the rated power and the swept area (in m2/kW) will offer similar advantages: high and very high equivalent annual full load hours Nh and capacity factors CF (CF = Nh/8760 and expressed in %), higher TWh delivered per installed or targeted GW, lower grid adaptation costs, higher annual hours of operation of wind farms at or near rated power and last but not least, a delivered kWh to be cost-competitive with electricity from new Chinese “clean coal” power plants within this decade .
If confirmed by data and results from the ongoing test of the prototype [5], the obvious advantages of such new models of wind turbines could help China to benefit from the advantages of this “silent revolution”, to surpass its wind power targets both in the medium term (200 GW and a minimum of 390 TWh in 2020) and in the long term (1000 GW in 2050), with a potential of more than 3000 TWh/year resulting from the systematic use of those new wind turbines models.
DISCLAIMER: the views, hypothesis and results expressed in this article are only those of the author and are proposed for a global overview of the topic, and neither the author nor GOLDWIND could be responsible of consequences of using them for actual wind power projects. Such actual wind power projects would require more detailed engineering studies based on more specific technical data of wind turbines from its manufacturer (such as certified power curve), specific assessment of potential sites characteristics and related actual investment and O&M costs, either in China or abroad.
Figure 1 shows the possible annual equivalent Full Load Hours ratio Nh (in kWh/kW.year) of a theoretical reference wind farm in China using a potential wind turbine model defined by the same diameter (115 m) and the same rated power
(2 MW) than the prototype new wind turbine model that the Chinese GOLDWIND Company [4] has put recently on tests
[5] (specific area Su = 5.19 m 2 /kW and specifics power Ps = 1/Su = 0.193 kW/m 2 ). Hypothesis for this wind farm to be put in industrial operation around 2016 is a total 13 % of wind farm losses due to actual conditions on the site and their difference with reference conditions defining the theoretical model (air density 1.225 kg/m 3 , Rayleigh distribution of wind speed at hub height) and a yearly availability of 97 %. The underlying model to calculate this ratio Nh is independent of other wind turbine manufacturer’s data and is described in reference [2]. Recent analysis in reference [6] for a wind turbine in the same reference conditions but without wind farm losses and with 100 % availability are in good accordance with results in figure 1 (Nh values here lower by around 10 to 15 % than in reference [6] in reference conditions and without wind farm losses and availability impacts, so corresponding to the hypothesis taken here on wind farm losses and availability). At the proposed reference average annual wind speed in a IEC 4 class site (average annual wind speed between 5 and 6 m/s at hub height) of Vm = 5.75 m/s at hub height, the estimated reference wind farm Nh value is around
1

2,790 hours/year, leading to an average annual wind farm capacity factor ACF = Nh/8760 = 31.8 % and an annual specific energy yield Eys = Ps*Nh = 537 kWh/(m 2 .year). This capacity factor value is higher than the average present values of wind power capacity factor in China as shown in figure 2 from [7]. At the low range of the IEC 4 class (5 m/s at hub height), the
Nh value is around 2,100 hours/year (corresponding to a capacity factor of 24 %) and around 3,000 h/y at the upper range
(6 m/s, with a corresponding capacity factor of 34.1 %). At 6.5 m/s at hub height, near the low range of the IEC 3 class (6 to
7.5 m/s), such a wind turbine would deliver an Nh value around 3,360 h/year and a capacity factor around 38.3 %.
3 500
3 400
3 300
3 200
3 100
3 000
2 900
2 800
2 700
2 600
2 500
2 400
2 300
2 200
2 100
2 000
2 099
2 789
3 359
42%
40%
38%
36%
34%
32%
30%
28%
26%
24%
22%
24,0%
31,8%
38,3%
BCCONSULT
Vm (m/s at hub height) BCCONSULT
Vm (m/s at hub height)
Figure 1: Equivalent full load hours per year Nh and capacity factor CF for the reference wind farm = f(Vm at hub height)
As one can see from figure 2, those capacity factors values compare well with the recent wind power capacity factors in
China and USA, including in Northern Chinese Provinces with high wind speeds, and including the “lost capacity factors parts” from frequent wind power curtailments due to the lack of present sufficient grid capacities (in red in figure 2).
Figure 2: average recent annual capacity factors in China and USA. Source [7]
So, commercial availability of those models of wind turbines for IEC 4 class sites with high Su values (in m2/kW) in complement of those already existing for the IEC 3 class is an obvious advantage for drastically lowering the distance between the areas of electricity consumption (mainly in the east and in the south of China and near the coastlines) and the
2

places of wind power production, as IEC 4 and IEC 3 classes areas (from 5 to 6 and from 6 to 7.5 m/s at hub height) are surely available in every provinces of China and near the large cities.
Figure 3 shows the corresponding specific productivity ratio Eys (in kWh/m2 of swept area and per year) for this model of wind turbine. Values are of course lower than with wind turbines with lower Su values (as Eys = Nh / Su), but they are sufficiently high and acceptable.
680
660
640
620
600
580
560
540
520
500
480
460
440
420
400
404
537
647
BCCONSULT
Vm (m/s at hub height)
Figure 3: Annual specific productivity Eys (kWh/m2.year) = Ps*Nh
But of course, the main parameter to take into account to analyze if this model of wind turbines can compete in the
Chinese wind power market is to look at the profitability of typical reference projects using this model.
Figure 4 shows the result of the corresponding analysis and all the detailed hypothesis and numerical values are available in the ANNEX. The cost ratio Ius (in Yuan/m2 of swept area) is on the horizontal axis, and the equivalent constant purchase rate Te (in Yuan/kWh at constant power purchase) of the kWh on n = 20 years to deliver the targeted profitability is on the vertical axis.
The targeted profitability to attract Chinese investors is defined here from an investor Weighted Average Cost of Capital
(WACC) of 5.66 % real, resulting from a targeted 10 % nominal return on equity and an interest rate of 7 % on the debt with a debt equity ratio of 80/20 and an inflation rate of 1.5 %. Beyond this WACC value, the targeted profitability is defined by a targeted Profitability Index (the ratio between the Net Present value NPV of the Project discounted at the WACC value and its initial investment cost I) of PI = 0.2, delivering a real project’s Internal rate of Return before tax on profit of IRR = 8 %, a simple pay-back time of SPBT = 9.8 years and a discounted pay-back time of DPBT = 14.8 years. This targeted profitability is higher than the minimum one quoted in reference [8] by a Chinese wind power expert. In the same reference [8], the present investment wind power cost ratio in China is announced at Iup = 8,000 Yuan/kW. For the new models with very high Su ratio (and including as in the case of the GOLDWIND 115 m and 2 MW model advanced technologies such as direct drive and a permanent magnet electricity generator), we assume here a differential investment cost ratio of + 20 %, leading to a Iup value for the first commercial series in around 2015 of Iup = 9,600 Yuan/kW and a corresponding Ius ratio (in Yuan per m2 of swept area) of Ius = 1,848 Yuan/m2. Beyond those reference values, figure 1 includes the impact of a Iup and Ius decrease by – 10 % and – 20 % (representative of cost decrease possible in 2017 and 2020) and of a Iup and Ius increase by
+ 10 % and + 20 % representative for example of short term potential export projects in markets and places where investments costs are at present higher than in China, or representative of small projects in very difficult conditions such as projects far from the existing grid in developing countries.
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The tilted lines in the graph refer to different hypothesis of average annual wind speed at hub height, from Vm = 5 to
6.5 m/s and including the reference value of 5.75 m/s. The two dotted horizontal lines refer to the present extreme wind power Feed-In Tariffs (FITs) values in China: 0.51 Yuan/kWh in the most windy provinces (and so, with available areas to use also with IEC2 and IEC1 classes of wind turbines) and 0,61 Yuan/kWh in the less windy provinces where this model of wind turbine should be an optimum one.
0,80
0,75
0,70
0,65
0,60
0,55
0,50
0,45
0,40
0,35
0,30
0,474
0,61
0,51
Vm (m/s)
5,00
5,25
5,50
5,75
6,00
6,25
6,50
FIT High
FIT Low
BCCONSULT Ius (Yuan/m2)
Figure 4: sensitivity of Te (in Yuan/kWh) against Ius (in Yuan/m2 of swept area) and Vm at hub height
One can see that for the reference project (round blue circle), the required selling price on the site with Vm = 5.75 m/s, is
Te = 0.474 Yuan/kWh (at constant power purchase power, so 100 % protected against the effect of the future inflation), or
Te = 5.5 c€/kWh at the present exchange rate of 8.61 Yuan/€. From figure 1, one can see also that with the above hypothesis, all sites from Vm = 5.1 to 6.5 m/s at hub height are compatible with the present high FIT value of 6.1
Yuan/kWh. And for Vm values higher than 5.5 m/s, the required selling price (at the reference Ius value of 1,850 Yuan/m2), is lower than the present onshore wind power FIT of 0.51 Yuan/kWh in the most windy clusters of Provinces. So, there is obviously room to design and to calculate a more advanced “tiered onshore wind power FIT” system than the present one based on a fixed FIT for each cluster of Provinces.
Even more important, as from reference [9] the new regulated selling price of kWh from sulfur-removed new “clean and efficient coal power plants” in the Guangdong Province is now around 0.5 Yuan/kWh , one can see that the above required reference selling price of Te = 0.48 Yuan/kWh on a low quality onshore site (Vm = 5.75 m/s at hub height) will be costcompetitive within only two or three years against the kWh selling price from new “clean coal” and high efficiency power plants, well before this official Chinese target which is 2020 !
Figure 5 gives the results of the same reference and sensitivity analysis with the ratio Iup (in Yuan per installed kW) on the horizontal axis. Of course, the conclusions from it are the same than above.
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0,80
0,75
0,70
0,65
0,60
0,55
0,50
0,45
0,40
0,35
0,30
0,474
0,61
0,51
Vm (m/s)
5,00
5,25
5,50
5,75
6,00
6,25
6,50
FIT High
FIT Low
BCCONSULT Iup (Yuan/kW)
Figure 5: sensitivity of Te (in Yuan/kWh) against Iup and Vm at hub height
To facilitate the comparisons with wind projects in Europe, figures 6 and 7 present the same results using Euros (at the present exchange rate of 8.61 Yuan/Euro).
4,5
4,0
3,5
3,0
6,0
5,5
5,0
9,0
8,5
8,0
7,5
7,0
6,5
5,50
Vm (m/s)
5,00
5,25
5,50
5,75
6,00
6,25
6,50
BCCONSULT Ius (€/m2)
Figure 6: sensitivity of Te (in c€/kWh) against Iup and Vm at hub height
5

7,5
7,0
6,5
6,0
5,5
5,0
4,5
4,0
3,5
3,0
9,0
8,5
8,0
5,50
Vm (m/s)
5,00
5,25
5,50
5,75
6,00
6,25
6,50
BCCONSULT Iup (€/kW)
Figure 7: sensitivity of Te (in €/kWh) against Iup and Vm at hub height
Figure 8 from [10] shows that as early as 2011, the Chinese onshore wind power market shifted from areas with an average wind speeds (IEC classes 1 and 2) to areas with low and very low wind speeds (IEC classes 3 and 4, down to 5 m/s at hub height): the percentages of new onshore wind power installations in IEC 3 and 4 classes increased from 43 % in 2010 (of which 35 % for class 4) to 45 % in 2011 (of which 45 % for class 4). And in 2012, the GOLDWIND Company successful bids were at 79 % in wind IEC classes 3 and 4 (of which 50 % in class 4 from 5 to 6 m/s at hub height), with mainly it 93 m/1.5
MW model (Su = 4.53 m2/kW, Ps = 0.221 kW/m2). This “success story” was obviously a reason for GOLDWIND to develop the new 115 m diameter/2 MW model with a larger Su value of 5.19 m2/kW (14.6 % more) and a higher rated power.
Figure 8: Market share of the Chinese wind power market according to IEC wind classes from [10]
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It is important to note that this company was N° 2 in the world wind market in 2013 with a 10.3 % share (see figure 9 right and reference [11]) from N° 6 in 2012, and is now the N° 1 in the Chinese wind power market with 23.3 % of the 16.1 GW installed in China in 2013 (see figure 6 left) from 19.5 % in 2012.
.
Figure 9: World and Chinese annual wind power markets (left) and 2013 world market shares (right) from [11]
Some conclusions can be drawn from this analysis and its results:

China has already discovered and applied the advantages of the “silent wind power revolution”, which is surely not so “silent” now in this country, but well known and publicized by wind turbine manufacturers, projects developers, investors, policy makers and national, regional and local regulatory authorities !

There are huge strategic advantages of using in China the new wind turbines models with very high Su values: o High and very high values for the equivalent full load hours of operation Nh and for the related average annual capacity factors CF in low and very low wind classes areas (IEC 3 and 4 classes). o Possibility to deliver related tens and then hundreds of TWhs near the places of electricity consumption, and not in distant regions with relevant problems of wind power curtailments from weak demand and delays, costs and limitations to build very long distance electricity transmission lines. o Much more TWh per year and higher penetration rates per installed or targeted GW. For example for the present official target of 200 GW installed in China in 2020, as the total installed wind power at the end of
2013 was 91.4 GW (of which 77.2 were grid connected at the end of December), shifting the large majority of the more than 100 GW to install from 2014 to the end of 2019 to the new wind turbines models with high and very high Su values could deliver more than 500 TWh/year in 2020, much more than the present targeted minimum of 390 TWh in 2020. And the present target of the Chinese wind power road map of
1,000 GW of wind power installed in China in 2050 could deliver much more than 3,000 TWh/year, more than 56 % of the around 5,300 TWh of electricity consumption in China in 2013 . o Lower cost of grid adaptation and development: “Much less copper per new TWh/year delivered”. o More opportunities for local developers and investors, including local communities and cities.

The use of new models of wind turbines with very high Su ratio will deliver also huge economic advantages: we have seen from the above reference case study that the price required for related wind farms, even in low and very low wind classes 3 ad 4 is fully compatible with the present Chinese onshore wind power FITs values, and that before the official target of 2020 it will be competitive against the kWh delivered by new “clean coal” efficient power plants.

There is room to easily improve the present and already efficient Chinese onshore wind power FIT system in order to give clear incentives to use those new efficient wind turbines models and to design a “full tiered FIT system”
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avoiding to over-pay the kWh in good windy areas, as in each region there is surely a vast choice of different quality sites and as the use of those new wind turbines models in low wind speed areas would not necessarily increase the over-cost of wind power FITs.
And so, China which is already the world leading country in the wind power market is also on the verge to be at the forefront for the demonstration and the dissemination of the energy and economic benefits of the “Silent wind power revolution”.
________________
[1] “Wind Power Silent Revolution: New Wind Turbines for Light Wind Sites”, Bernard Chabot, online May 6, 2013 and downloadable at: http://www.renewablesinternational.net/turbines-in-low-wind-areas/150/505/62498/
[2] “2014: The Year When the Silent Onshore Wind Power Revolution Became Universal and Visible to All? Evidence of
Potential Onshore Wind High and Very High Capacity Factors On Sites With 5 to 10 m/s Average Annual Wind Speeds at Hub
Height” , online January 2, 2014 and downloadable at: www.renewablesinternational.net/2014-the-year-for-weak-windturbines/150/435/75726/
[3] “Bright economic and strategic perspectives for onshore wind power in medium to low wind speed areas”, Bernard
Chabot, WindTech International, Volume 9, N°6, September 2013.
[4] GOLDWIND web site: http://www.goldwindglobal.com
[5] “Goldwind installs low-wind prototype”, Wind Power Monthly, http://www.windpowermonthly.com/article/1290791/goldwind-installs-low-wind-prototype
[6] “Quick Assessment of Energy Yield”, J. P. Molly, DEWI Magazin N° 44, February 2014, downloadable at: http://www.dewi.de/dewi/index.php?id=74&L=3&tx_ttnews[tt_news]=153&cHash=65e46e685ec0ed191ae50877f643f306
[7] “Spilled Wind: An Update on China's Wind Integration Challenges”, Michael Davidson, March 4, 2014, downloadable at: http://theenergycollective.com/michael-davidson/346951/spilled-wind-update-china-s-wind-integration-challenges
[8] “China’s Idle Wind Power Curbs Tariff Cuts, Regulator Says”, Bloomberg News Editors, April 11, 2014, downloadable at: http://www.renewableenergyworld.com/rea/news/article/2014/04/chinas-idle-wind-power-curbs-tariff-cuts-regulatorsays
[9] “Wind power gains momentum”, China Economic Net, April 18, 2014, downloadable at: http://en.ce.cn/Insight/201404/18/t20140418_2683839.shtml
[10] “2012 Annual Results”, GOLDWIND, presentation downloadable at: http://www.goldwindglobal.com
[11] “2013 Annual Results”, GOLDWIND, presentation downloadable at: http://www.goldwindglobal.com
8

Project: Test of model 115/2MW
Place: China
Vm at hub heigh
Hub heigh
5,75
110 m/s m
Wind turbine: XX 115/2
D 115,0
S = PI*D^2/4
Pu
Ps = P/S
Su = S/P = 1/Ps
N wind turbines
10 387
2 000
0,193
5,19
10 m m2 kW kW/m2 m2/kW
P wind farm
Ey
Nh = Ey/P
ACF = Nh/87,6
Eys = Ey/S
I
20,00
55 772
2 789
31,83
537
22,300
MW
MWh/year h/year
% kWh/m2.y
M€ t n
5,66
20
CRF(t,n) 0,08476
Iup = I/P 1 115
Ius = I/S
Domu = Dom/P
Kom = Dom/I
PI
Ci
Com
ODC = Ci + Com
% real year
215
40,0
3,59
0,200
€/kW
€/m2
€/kW.year
%
0,034 €/kWh
0,014 €/kWh
0,048 €/kWh
Margin
Te
0,007 €/kWh
0,055 €/kWh
Te 5,50 c€/kWh
IRR 7,98% % real
DPBT
SPBT
14,8
9,8 years years
70,3% 61,6%
29,7% 26,1%
100% 87,7%
12,3%
100%
Values of a tariff at two levels T1 and T2, J fixed
J (years at T1) 5 years
CRF(t,J) 0,23517
Tariff on J years T1 8,00
Tariff on (n-J) years T2
Te cst equiv. on n years
4,09
5,50 c€(0)/kWh c€(0)/kWh c€(0)/kWh
Year "zero" tariff = f(fixed part f, inflation i)
Fixed part f
Indexed part (1-f)
Future inflation i
Variation v
CRF(t,n,v)
Year "0" tariff Tov
Wind Farm losses
WF & Grid Availability
40
60
1,50
-0,591
0,08920
5,79
13,00
97,00
%
%
%
%/year c€/kWh
%
%
Calculation of t = WACC real before tax
Part of Equity 20,00 %
Part of Debt
ROE
Interest on debt
80,00
10,00
6,55
%
% nominal
% nominal
Inflation i
(% nominal)
WACC = t
1,50
7,24
5,66
%
% nominal
% real
Targeted Profitability Inde x (PI) V alues According to R isks and Gro wth Strategies
-0,1 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 +
Non
P rofitable
T ow ards failu re
P rojects
Surviving
No
G rowth
N o Risks at all
D efensive Gro wth
O ffensive Gro wth
L ow Risks
C rash program me
Leadership
High to v ery h igh risks
Table 1: details of the economic analysis of the reference wind farm (in Euro)
1
2
Currency: Chinese Yuan
Exch. rate: currency/€: 8,61000
Parameter
I (Million)
Iup = I/P
Chinese Yuan
192,00
9 600
3 Ius = I/S
4 Domu = Dom/P
5 Ci
8
9
6 Com
7 ODC = Ci + Com
Margin
Te
1 848
344,4
0,292
0,124
0,415
0,058
0,474
Table 2: Main hypothesis and results for the reference wind farm in Yuan (exchange rate: 8.61 Yan/Euro)
9

IEC class
(1, 2, 3 or 4)
4
4
4
4
3
3
3
Vm Iup (€/kW): 892 1 003 1 115 1 226 1 338
Nh: / Ius: 172 193 215 236 258
5,00 2 099
5,25 2 352
5,50 2 580
5,75 2 789
6,00 2 985
6,25 3 174
6,50 3 359
5,85
5,22
4,76
4,40
4,11
3,87
3,65
6,58
5,87
5,35
4,95
4,63
4,35
4,11
7,31
6,52
5,95
5,50
5,14
4,83
4,57
8,04
7,17
6,54
6,05
5,65
5,32
5,02
5,80
5,48
8,77
7,83
7,14
6,60
6,17
Table 3: results of the sensitivity study for the reference wind farm in Euro
IEC class
(1, 2, 3 or 4)
4
4
4
4
3
3
3
Currency:
Vm
Constant Equivalent Tariff Te = f(Ius, Nh)
Yuan Exchange rate: 8,61
Iup (U/kW): 7 680 8 640 9 600
Yuan per €
10 560 11 520
Nh: / Ius: 1 479
5,00 2 099 0,504
5,25 2 352 0,449
1 664
0,566
0,505
1 848
0,629
0,562
2 033
0,692
0,618
2 218
0,755
0,674
5,50 2 580
5,75 2 789
6,00 2 985
6,25 3 174
6,50 3 359
0,410
0,379
0,354
0,333
0,315
0,461
0,426
0,398
0,375
0,354
0,512
0,474
0,442
0,416
0,393
0,563
0,521
0,487
0,458
0,433
0,614
0,568
0,531
0,499
0,472
Table 4: results of the sensitivity study for the reference wind farm in Yuan
_________________________
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