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Noise is mostly generated by the equipment and machinery used for geothermal utilisation as well as the noise from reserve wells. Landsvirkjun closely monitors its geothermal operations to ensure that noise levels remain within the legal requirements.

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Noise levels under the legal requirements

Noise is defined as an undesirable sound from e.g. anthropogenic sources, traffic or industrial activities. Sound intensity is measured in decibels (dB) or decibels A (dB (A)) which simulates the sense of the human ear. The operational areas at Krafla and Bjarnarflag, where geothermal electricity generation takes place, as well as the construction area at Þeistareykir are zoned as industrial areas. The Icelandic regulation on noise specifies a reference limit for industrial zones of 70 dB (A) at site boundary.

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Noise intensity in decibels (dB) measured during various human activities

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Landsvirkjun sets reference limits for popular tourist destinations within industrial zones to ensure that sound levels do not exceed 50 dB (A).

Noise is mostly generated by the equipment and machinery used for geothermal utilisation as well as the noise created by steam discharging from reserve wells. Operations at the Krafla and Bjarnarflag Geothermal Power Stations are relatively stable throughout the year and noise levels are therefore also stable. However, the noise from wells can vary and is dependent on their activity level. Noise levels depend on the number of reserve wells and on weather conditions.

Noise levels are monitored on a regular basis at chosen locations and continuous monitoring systems were installed in each production area (Krafla, Bjarnarflag and Þeistareykir).

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Krafla and Bjarnarflag

Noise level measurements

Monitoring location at Krafla
Monitoring location at Bjarnarflag
Power stations
Well 35
Shaded areas on the map show industrial areas
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Measuring noise levels

The noise measurement plan was altered in 2014 as the frequency of monitoring was increased and continuous noise level meters were installed in three production areas. New monitoring points were identified for isolated measurements which were subsequently decreased. Noise levels will be measured in these locations up to six times a year.

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Krafla Geothermal Station area

Noise level measurements were carried out at Krafla in May, June, August and November. Wells were active during measurements conducted in May and June. The results showed that noise levels were below the set reference limits for industrial zones in all cases.

Equivalent sound levels in the Krafla area 2014. All values are in dB(A).

Monitoring location

Date 

1

2

3

4

5

6

7

8

28.05 35 47 - 38 45 61 43 53
25.06 48 44 30 41 46 61 43 53
28.08 54* 43 50* 33 48 54* 43 56
11.11 41 43 35 47 44 45 42 56

*Sightseeing flights affected monitoring.

The results for monitoring station 6 are interesting as they show how reserve wells can affect their immediate environment. Monitoring station 6 is in close proximity to well 35 which was capacity tested during the summer of 2014 when noise measurements were recorded. Noise levels reached 61 dB(A) when well 35 was active in May and June but reached 54 dB(A) in August and 45 dB(A) in November when the well had been closed. Sightseeing flights were active in the area when noise measurements were carried out in August, which affected results.

Víti and Leirhnjúkur are popular tourist areas in close proximity to the industrial area at the Krafla Geothermal Power Station. The walking path up to Leirhnjúkar falls within the area for monitoring station 7. Noise levels were 43 dB (A) during all four measurement periods. Assessing the effect of production in these areas is difficult but changes to noise levels in and around well 35 seemed to have had little effect.

The results for monitoring station 8 (Víti) were similar for all four measurement periods, reaching 55 dB(A). Measurements are conducted on the south side of the crater edge closest to the wells. Noise levels are probably lower in other areas surrounding Víti as they are further from the wells and are better protected from operations.

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Bjarnarflag Geothermal Power Station area

Noise measurements were conducted at Bjarnarflag in June and November. The results showed noise levels to be 50 dB(A) or below during all measurement periods.

Equivalent sound levels in the Bjarnarflag area 2014. All values are in dB(A).

Monitoring location

Date 

1

2

3

4

5

6

7

8

9

10

24.06 50 44 48 46 50 40 29 40 35 47
11.11 42 43 46 40 36 35 25 39 49 49

Noise levels were recorded at 50 dB(A) and 42 dB(A) at monitoring station 1 by Hverarönd. The area cannot be seen from the Bjarnarflag or Krafla Stations and noise levels can mostly be attributed to active hot springs in the area, traffic and weather conditions.

Monitoring stations at Grjótagjá, Hverfjall and the Skútustaðahreppur Primary School in Reykjahlíð (stations 6, 7 and 8) showed noise levels to be 40 dB(A)or just below during all measurement periods. Noise levels were higher by the national highway, production area and tourist spots. Traffic within the areas can have a significant effect on measured values.

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Þeistareykir area

Noise measurements were conducted at Þeistareykir in May, June, September and November.

Equivalent sound levels in the Þeistareykir area 2014. All values are in dB(A).

Monitoring location

Date 

1

2

3

4

5

6

22.05 28 31 30 50 43 42
26.06 28 38 29 55 34 29
09.09 37 40 38 43 53 57
24.11 48 60 34 65 42** 51

**Monitoring period too short to be viable.

Summer construction work had not started at Þeistareykir when measurements were carried out in May. Weather conditions were mild and exterior noise was minimal. Measured values can therefore be evaluated as the lower limit for noise levels in the area (particularly at monitoring stations 1 – 3). The highest value was 50 dB(A) in Bóndhólsskarð where wells were being ‘bled’ on a nearby drilling platform. The term ‘bleeding’ refers to the discharge of minimal steam flow from the well head to maintain temperatures in wells and equipment.

Construction work was carried out in June and September and contractors were quite active in the area in November. Discharge tests were conducted during this period and all wells were therefore active. Active wells are the greatest source of noise within geothermal production areas and their effects can be clearly seen in measured values. Measured values are significantly higher in November than they are in previous measurements, particularly in monitoring stations close to drilling areas with active wells (monitoring stations 1, 2 and 4).

Noise levels are clearly at their highest level when discharge tests are being conducted. However, measured levels are all within the set reference limits for industrial areas or 70 dB(A).

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Þeistareykir

Noise level measurements

Monitoring locations
Shaded areas on the map show industrial areas