Control over Environment Impacts 
Noise Control on Wind Farms

I. Noise effect during construction and preventive measures
Major sources of noises during the construction of wind farms are excavators, concrete mixing machines, and bulldozers. According to the attenuation model of point source noises, estimated values of noises from construction machines that tend to attenuate by distance are listed in the table below.
Estimated noise values of construction machines

  Noise Source

Estimated noise value (dB(A))

5m

10m

20m

40m

50m

60m

80m

100m

150m

300m

Excavators

84

78

72

66

64

63

60

58

55

47

Concrete mixing machines

87

81

75

69

67

66

63

61

58

50

Bulldozers

86

80

74

68

66

65

62

60

57

49

It can be seen from the table that at a distance from the noise source of 300m, the noise will become less than 55dB and the requirement of LAeq≤55dB during daytime in the I-level standard of Standard of environmental noise of urban area (GB3096-93) can be satisfied. During construction, operating noises can be cut down by strengthening the maintenance of equipment and keeping machineries lubricated. In the meantime, management shall be reinforced so as to reduce noises made during the maintenance of construction equipment.
II. Noise effect during operation and preventive measures
Noises produced by wind turbines during their operations include noises produced when winds sweep the blades, noises produced when the internal machineries of machine sets run, and noises from electrical equipment, among which first place shall given to noises produced when the internal machineries of machine sets run. Taking wind turbines with a single set capacity of 1,500kW and a hub height of 65m as an example, the noise power level at the wheel hub will be LWA≈101dB (A) during operation.
As any two wind generating sets are rather far from each other, each wind turbine can be regarded as a single point noise source. Therefore, noise calculation can be conducted by adopting the formula of point noise attenuation in a free space; the formula is as follows: 
LA(r)=LWA-20log(r)-11
LA(r)=LWA-20log(r)-11
Where: LWA is the A noise power level of the point noise source (dB (A)), and r stands for the horizontal distance from the noise source (m).
See the table below for calculating results.
Calculating results of the noise attenuation of a single wind turbine(Unit: dB)

  Horizontal distance from the noise source (m)

10

50

100

150

200

LA(r)

  70

56

50

46

44

It can be seen from the table that at a distance from the noise source of 10m during daytime and at a distance from the noise source of 200m at night, the requirement of ≤55dB(A)during daytime and ≤45dB(A)at night in the I-level standards of Standard of environmental noise of urban area (GB3096-93) can be satisfied without any influence on residents in the neighbourhood.
The main impact of wind turbines on birds is birds’ dash against wind turbines. The largest sweep height that blades of wind turbines used in this round can reach 100m or so while the height at which migrant birds fly tends to be higher than 150m, so birds in their migrant fights will not be much affected. Nevertheless, bid flocks landing at night may bounce onto blades that they can not see. The distance between any two wind turbines is 300m~500m; In general, it is believed that such a distance is enough for birds to fly across and will not disturb birds’ flights.

Desulfurization of Thermal Power

As shown in data, the annual direct economic losses resulted from acid rains in China have been over RMB110 billion yuan in recent years. The government has invested a large quantity of funds in the treatment of pollutions caused by acid rains and physical health of human beings thus endangered. The main reason for the occurrence of acid rains in large areas is the excess discharge of sulfur dioxide. In recent years, it can be said that urges for desulfurization from the government to thermal power plants are very urgently; thus, the awareness of combining the construction of the electric power industry with environment protection has become deeply rooted in people’s mind. Various thermal power plants change from passive responding to taking actions actively, which thus changed the situation of desulfurization greatly; in the meantime, a rapid prosperity has been facilitated and a large industry with infinite potentials has come into being. As shown by data from the National Development and Reform Commission, by the end of 2008, the installed capacity with flue gas desulfurization equipment in various thermal power plants all over China had surpassed 379 million kilowatts, accounting for about 66% of the overall installed capacity of coal-fueled power plants.
The overall installed capacity of thermal power plants in the holding of Longyuan Group amounts to 1.875 million kW: the installed capacity of Jiangyin Sulong Power Generation Co., Ltd. amounts to 1.21 million kW and that of Nantong Tianshenggang Power Generation Co., Ltd. amounts to 660,000 kW. To respond to the call of the government to “launch large machine sets while reducing small machine sets”, four small machine sets has been shut down while two large one million kW machine sets are to be constructed in Tianshenggang.


  Tianshenggang Power Plant

While building up large-scale thermal power plants, Longyuan Group has actively launched the transformation of equipment and technologies with environment-protecting facilities for coal combustion and flue gas desulfurization enlarged; and desulfurization equipment has been installed in all thermal power plants. By technique, fuel gas desulfurization can be classified into desulfurization by wet processes, desulfurization by semi-dry processes, and desulfurization by semi-dry processes; the fundamental principle is to use a certain kind of alkaline substance as the SO2 absorbent which will react with smoke and gas to generate corresponding substances. Typical technologies of desulfurization by wet processes have been adopted at Jiangyin Sulong Power Plant: smoke and gas from the hearth will come into the absorption tower of the smoke and gas desulfurization system; plaster produced by the desulfurization system will be sold to cement plants and plaster plate factories after dehydrated, thus realizing the comprehensive utilization of resources. At present, desulfurization by wet processes is a kind of desulfurization technology that is the most mature with the largest number of practical performances and the most stable operating status; and the desulfurization rate can amount to over 90%.


  Jiangyin Sulong Power Plant

Effects of tidal power stations on biodiversity

When tidal power plants built up, the water temperature will not change greatly while the salinity drops slightly; the water quality in the reservoir will not change largely and the sediment accumulation rate in the water area in a reservoir will be generally 1~2cm/y. The main impact lies in that the change margin of water level in the reservoir will dwindle, the tidal flow capacity will be reduced, and the beach sands will be flooded with seawater for a long time. As there will occur changes to the discipline for changes in the tidal levels in the reservoir, it will be inevitable to bring impacts to the biological resources in the subtidal zone and the intertidal area as well as the aquiculture.

I. Impacts to the biological resources in the subtidal zone
By category, the biological resources in the subtidal zone can be classified into fish, shrimps, oysters, aquatic plants, etc. The quantities of resources are related to the water temperature, salinity, and quantity of living things. Usually, the scope of water temperature and that of salinity suitable for such biological resources are extensive; changes in water temperature and salinity will not affect them greatly after the construction of tidal power stations. As shown by surveys on the Jiangxia Test Tidal Power Station in Zhejiang Province which has been in operation for many years, such resources as fish and shrimps are fairly abundant in the reservoir of Jiangxia Test Tidal Power Station while the production of shellfish farming is favorable; such a fact shows that after the construction of a tidal power station, the status of plankton resources is favorable and the construction of tidal power stations is advantageous to the mariculture in the subtidal zone. In addition, analyzed from the expected results that the salinity will drop down in the reservoir when a tidal power station built up and the impacts of freshwater runoff to the environment of the reservoir are fairly obvious, such a fact that the contents of organic substances and nutritive salts in the reservoir are likely to somewhat improved will be advantageous to the reproduction of diatom in the water area, especially to the increase of the quantity of low-salinity and euryhaline diatom. Therefore, abundant food will be provided for various kinds of fish, shrimps, and shellfish that eat zooplanktons and phytoplanktons while favorable conditions have been created for the development of artificial culture of fish, shrimps, and shellfishes in the reservoir in the future.

II. Impacts to the biological resources in the intertidal area
Most varieties of living things in the intertidal area tend to select certain tidal areas somehow. After the construction of a tidal power station, changes in the high and low levels in various tidal areas will make it possible for living things originally in a certain tidal area to adapt to the tidal area changed, thus affecting the growth and reproduction of those living things. To adapt to the environment, such living things are likely to move to inhabit and grow in a suitable tidal area once again after a period of time. As a result, the main impact to the biological resources in the intertidal area is represented with the reduction of the intertidal area, thus making the quantity of living things in the intertidal area reduce.

Phase-out Program; Photovoltaic Generation