15.2.1
International Commission on Non-ionizing
Radiation Protection (ICNIRP)
15.2.1.1
With reference to Clause 3.4.16.1 of the EIA Study
Brief, guidelines
on limits of exposure to EMF
issued by the International Commission on Non-ionizing Radiation Protection
(ICNIRP) in Year 1998 should be followed.
The ICNIRP guidelines were recognized by the World Health Organization
(WHO). EMF generated from the proposed EFs
and the proposed ESSs shall comply with the guidelines stated in Table 15.1.
Table 15.1 Guidelines
on Limits of Exposure to 50Hz Power Frequency Electric and Magnetic Fields
Issued by ICNIRP
|
Exposure Characteristics
|
Electric
Field Strength, V/m [a]
|
Magnetic Flux Density, μT [a]
|
|
General
Public
Continuous
|
5,000 [b]
|
100 [b]
|
|
Occupational
Continuous
|
10,000 [b]
|
500 [b]
|
Remarks
[a] Unperturbed root-mean-square (rms) values.
[b] The standards stipulated in
Guidelines following the ICNIRP (1998) limits for 50 Hz EMF.
15.2.2
Hong Kong Planning Standards and Guidelines
15.2.2.1
As stated in Section 2.3.10 of Chapter 7 of the
Hong Kong Planning Standards and Guidelines (HKPSG), the EMF exposure limits
promulgated in the guidelines issued by ICNIRP in 1998 are adopted. The relevant standards are presented in Table
15.1.
15.3.1
Potential
Sources of Electric and Magnetic Field Impact
15.3.1.1
EMF
are present everywhere in our environment.
Electric field is generated by difference in voltage. The higher the voltage, the stronger will be
the resultant electric field. Magnetic
fields are created by electric current.
The greater the current, the stronger the magnetic field. EMF are produced by virtually all electrical
consumer appliances, computer terminals, wiring in homes, offices, electrical
facilities and power cables / transmission lines. Potential EMF impacts from the project would
be expected from the operation of the proposed EFs at TKO 132 and the operation
of the proposed ESSs at TKO 137. The
locations of the proposed EFs and the proposed ESSs are presented in Figure 2.4 and Figure 2.5.
15.3.1.2
Potential
cumulative EMF impacts from the concurrent projects, i.e. planned power cables
connected to the EFs at TKO 132 and the planned power cables connected to the
proposed ESSs at TKO 137 would also be expected.
15.3.2
Identification
of Representative Electric and Magnetic Field Sensitive Receivers
15.3.2.1
Representative
EMF sensitive receivers nearby the EFs and ESSs are identified and listed in
below Table 15.2. Locations of the representative
EMF sensitive receivers are shown in Figure 2.4 and Figure 2.5.
Table 15.2 Identified Representative Electric and Magnetic
Field Sensitive Receivers
|
EMF Source
|
Sensitive Receivers
|
Land Use
|
Approximate Distance between the Boundary of Sites of the Proposed
EMF Source and Sensitive Receiver, m
|
|
Electricity
Facilities (EFs) at Site OU1 at TKO 132
|
On
Luen Village
|
Green Belt[2]
|
140
|
|
Proposed
Construction Waste Handling Facilities (CWHF)
|
Other Use (Construction Waste Handling
Facility)
|
0 [1]
|
|
ESS
at Site OU1 at TKO 137
|
Proposed
Residential Site PU1&2
|
Residential
|
30
|
|
Proposed
Open Space O1
|
Open Space
|
0 [1]
|
|
ESS
at Site OU2 at TKO 137
|
Proposed
Open Space O8
|
Open Space
|
0 [1]
|
|
Proposed
Green Filling Station
|
Other Use
|
0 [1]
|
|
Proposed
Residential Site (PU6)
|
Residential
|
25
|
|
Proposed
Secondary School (E5)
|
Educational
|
30
|
|
Remarks:
[1] The site of the proposed sensitive
receiver would be located immediately adjacent to the site of the proposed
EMF source.
[2] On Luen Village are
residential uses on area zoned as Green Belt.
|
15.4
Evaluation of Potential
Impact
15.4.1
Electric
and Magnetic Field due to the Project
15.4.1.1
In
TKO 137, there would be two proposed 132 kV ESSs located at proposed Sites OU1
and OU2, respectively, as shown in Figure 2.4. Their design would follow the
requirements stated in Section 2 of Chapter 7 of Hong Kong Planning
Standards and Guidelines. The two
proposed 132 kV ESSs would be of the same nature, the same operation voltage,
the same major plants, similar design of housing major plants inside similar
structure of reinforced concrete as an existing 132 kV ESS. Therefore, it is expected that the EMF from
the two proposed ESSs would be similar to that of an
existing 132 kV ESS. With reference to the
project profile of the approved direct application of environmental permit for Extension
Project for the Existing Tseung Kwan O 400 kV Substation (PP-072/1999), EMF
measurement was conducted inside Tuen Mun 132 kV Substation (i.e. 0m away from
the source). The measured electric field
strength was 10 V/m (as 0.01 kV/m in PP-072/1999) and the measured magnetic
flux density was 4.7 μT (as 0.047 mT in PP-072/1999), complying with
the limits in Table 15.1 by well below of the limits over 99% and over 95%, respectively. Similar electric field strength and magnetic flux
density would be expected inside the proposed ESSs at TKO 137. Since EMF would decrease rapidly with
increasing distance, EMF outside the proposed ESSs would be lower than that
inside the ESSs. Therefore, it is
expected that EMF at the sensitive receivers located outside the proposed ESSs listed
in Table 15.2 would comply with the limits in Table 15.1. No adverse impact from the exposures
of EMF generated from the proposed ESSs at TKO 137 would be anticipated.
15.4.1.2
Design
of the EFs at TKO 132 would also follow the requirements stated in Section 2 of
Chapter 7 of Hong Kong Planning Standards and Guidelines. Based on the latest available information,
the proposed EFs would consist of High-Voltage Direct Current (HVDC) and High-Voltage
Alternating Current (HVAC) Converter Blocks, which are reinforced concrete
structure housing major plants, including transformer, a series of reactor,
shunt reactor and cooling fans, etc. As
confirmed by respective proponent of the EFs, the EFs would house equipment of
up to 400 kV. Hece,
it is considered that the EFs would be similar to that
of existing 400 kV ESSs. Therefore, it is expected that the EMF from
the proposed EFs would be similar to that of existing
400 kV ESSs. With reference to PP-072/1999,
EMF measurement was conducted inside Tsz Wan Shan 400 kV ESS (i.e. 0m away from
the source) and the measured electric field strength was 10 V/m (as 0.01 kV/m
in PP-072/1999) and the measured magnetic flux density was 59 μT (as 0.059 mT in PP-072/1999), complying with
the limits in Table 15.1 by huge margin of over 99% and over 40%, respectively. With reference to PP-072/1999, EMF
measurement was also conducted at 6 m to 18 m from the reinforced concrete
structure of the Shatin 400 kV Substation, and the measured electric field
strength ranged from 3 V/m to 7 V/m and the measured magnetic flux density
ranged from 0.89 μT (as 8.9 mG in PP-072/1999) to 6.52 μT (as 65.2 mG in PP-072/1999), complying with
the limits in Table 15.1 by huge margin of over 99% and over 90%, respectively. Based on the above, it is expected the EMF
outside the proposed EFs would comply with the limits in Table 15.1, and the EMF at the sensitive receivers located outside the proposed
EFs listed in Table 15.2 would comply with the limits in Table 15.1. Based on the latest available
information at this stage, no adverse impact from the exposure of EMF generated
from the proposed EFs at TKO 132 would be anticipated.
15.4.1.3
As
identified as DP6 in Table 1.1, the EFs requires an Environmental
Permit (EP) to construct and operate under the EIAO. As the detailed design information is not yet
available at the time of the preparation of the Report, an Environmental Permit
(EP) would be applied separately by the proponent of the EFs, with a EIA study as necessary, following the EIAO mechanism to
ensure that no adverse impact from the exposure of EMF generated from the
proposed EFs would be anticipated.
15.5
Mitigation Measures
15.5.1.1
Based
on the latest available information at this stage, no adverse impact due
to exposure to EMF would be anticipated from the proposed EFs and ESSs. No mitigation measures would be required,
given that the design of the proposed ESSs would be similar
to that of existing 132 kV ESSs, while the design of the proposed EFs
would be similar to that of existing 400 kV ESSs.
15.5.1.2
Nevertheless, the design of the EFs would be subject
to further review by the proponent of the EFs. Therefore, in view of the uncertainty, the proponent
of the EFs would apply for an Environmental Permit (EP) separately when the design information is available, following the EIAO
mechanism for the construction and operation of the proposed EFs to ensure that
no adverse impact from the exposure of EMF generated from the proposed EFs
would be anticipated.
15.5.1.3
During the application of the EP for the EFs,
should any changes, including but not limited to update of criteria and design
information, lead to the need of mitigation measures, the proponent of the EFs
should implement as necessary to ensure compliance to the criteria at the time
of the EP application.
15.6.1.1
Based
on latest available information, no overhead power cables would be
proposed/planned within the Project site or in the vicinity of the Project
site. EMF impacts due to overhead power transmission
line to the Project site and the vicinity of the Project site would not be
anticipated.
15.6.1.2
The
submarine power cables and the underground power cables
would be constructed and operated under separate project(s). Based on latest available information,
submarine power cables would be used to deliver electrical power to the EFs,
which provide electrical power to users via underground power cables. Underground power cables would be used to
deliver electrical power to and from the proposed ESSs at TKO 137. The potential cumulative impact due to the
submarine and underground power cables would be assessed below.
15.6.1.3
Underground and submarine power cables are
normally well-insulated to avoid electrical current loss. Therefore, it is expected that the EMF from
the underground and submarine power cables would be largely confined by the
insulation layer.
15.6.1.4
With
reference to the EMF measurement result in the project profile (PP-005/1998) of
the approved EIA for 132kV Overhead Line From Tsuen Wan to Sham Tseng (AEIAR-023/1999), EMF
measurements were conducted at 1 m above ground for existing 400 kV and 132 kV
underground power cables that located 1 m below ground. The distance between measurement location and
existing 400 kV and 132 kV underground cables is 2m in total. The measured electric field strength was less
than 10 V/m (as <0.01 kV/m in PP-005/1998) for
both 400 kV and 132 kV underground power cables, while the measured magnetic
flux density was 5.2 μT (as 0.0052 mT in PP-005/1998) for 400 kV
underground power cables and 0.3 μT (as 0.0003 mT in PP-005/1998) for 132 kV
underground power cables, all complying with the limits in Table 15.1 by huge margin of over 99% and over 90%, respectively. It would be expected that the proposed
underground power cables would adopt similar design as existing underground
power cables, such that the EMF due to the underground power cables would
comply with the limits in Table 15.1. Due to the minimal EMF
from underground power cables, no adverse cumulative impact from underground
power cables would be expected.
15.6.1.5
For
submarine cables, with reference to literature, electric field is generally contained by the cable as an industrial
standard. No adverse cumulative electric
field impact would be anticipated from submarine cable. Magnetic flux density were measured at
0 m to 2 m from various submarine cables of 11 kV to 500 kV voltage in the
European area to be in the range of 0.004 μT to 72 μT, which comply with the
limits in Table 15.1 by over 25% margin. Sensitive
receivers would be expected to be located on land which are well beyond 2 m separation
from a submarine power cable, and EMF would decrease rapidly with increasing distance, the EMF due to a submarine
cable at any sensitive receivers on land would be expected much lower than that
under water within 2m from a submarine cable.
EMF compliance to ICNIRP limit at the sensitive receivers would be
expected. Hence, it is expected that no adverse EMF impact to sensitive
receivers from submarine power cables.
15.6.1.6
As
mentioned above, the EMF impacts arose from the power cables for the EFs and
ESSs would be anticipated well below the limits in Table 15.1. Therefore, it is anticipated
that the cumulative EMF would comply with the limits. No adverse cumulative
electric and magnetic fields impacts would be expected from the Project and
concurrent projects.
15.7.1.1
Based on above Section 15.4, no adverse EMF impact would be anticipated from the Project.
15.7.1.2
Based on above Section 15.6, no adverse cumulative EMF impact would be anticipated
from concurrent projects of power cables connecting to the ESSs and EFs.
15.7.1.3
Nevertheless, the design of the EFs would be subject
to further review by the proponent of the EFs.
Therefore, in view of the uncertainty, the proponent of the EFs would
apply for an Environmental Permit (EP) separately when the design information is available, following the EIAO
mechanism for the construction and operation of the proposed EFs to ensure that
no adverse impact from the exposure of electric and magnetic fields generated
from the proposed EFs would be anticipated.
15.8.1.1
Based on the above assessment in Section 15.4 and Section 15.6, no adverse impact due to exposure to EMF is anticipated for the two ESSs and their associated power
cables in TKO 137. Environmental
monitoring and audit is therefore deemed not necessary
for TKO 137.
15.8.1.2
Based on the above assessment in Section
15.4 and Section
15.6, no adverse impact due to exposure to EMF is anticipated for
EFs and their associated power cables in TKO 132. In view of the uncertainty,
the proponent of the EFs would apply for an EP separately when the design information is available, following the EIAO
mechanism for the construction and operation of the proposed EFs to ensure that
no adverse impact from the exposure of EMF generated from the proposed EFs
would be anticipated. If found necessary, environmental
monitoring and audit requirements would be determined in the separate EP
application.
15.9.1.1
Electric
and magnetic field impact assessment has been conducted in accordance
with the requirements stated in Clause 3.4.16 of the EIA Study Brief.
15.9.1.2
The
proposed 132 kV ESSs at TKO 137 would be of the similar nature and design as
existing 132 kV substations. The EMF due
to the proposed ESSs would be expected similar to
existing 132 kV substations. With
reference to EMF measurement inside the existing Tuen Mun 132 kV Substation,
the electric field strength and the magnetic flux density were respectively measured
at 10 V/m and 4.7 μT, which complied with the ICNIRP limit by huge margin of over 99% and
over 95%, respectively. EMF outside the
proposed ESSs would be lower than that inside the ESSs, since EMF would
decrease rapidly with increasing distance.
Hence, it is expected that the EMF from the proposed ESSs at sensitive
receivers would comply to the ICNIRP limit.
No adverse EMF impact would be anticipated from the proposed ESSs.
15.9.1.3
The
proposed 400 kV EFs at TKO 132 would be of the similar nature and design of
existing 400 kV substations. The EMF due
to the proposed EFs would be expected similar to
existing 400 kV substations. With
reference to EMF measurement inside the existing Tsz Wan Shan 400 kV Substation,
the electric field strength and the magnetic flux density were respectively measured
at 10 V/m and 59 μT, which complied with the ICNIRP limit by large margin of over 99% and
over 40%, respectively. With reference
to EMF measurement in the vicinity of the existing Shatin 400 kV Substation,
the electric field strength and the magnetic flux density were respectively measured
up to 7 V/m and 6.52 μT, which complied with the ICNIRP limit by huge margin of over 99% and
over 90%, respectively. Hence, it is
expected that the EMF from the proposed EFs at sensitive receivers would comply
to the ICNIRP limit. No adverse EMF impact
would be anticipated from the proposed EFs, based on latest available
information.
15.9.1.4
Cumulative
EMF impact would be expected from concurrent projects, i.e. underground and
submarine power cables connecting to the proposed EFs and the proposed ESSs. With reference to previous EMF measurement
result at existing underground power cables, measured electric field strength
and magnetic flux complied with the ICNIRP limit by huge margin of over 99% and
over 90%, respectively. For submarine
power cables, referenced literature indicated electric field should be well
contained within the submarine power cable as an industrial standard, while
magnetic field generated from a submarine power cable at 2 m from the
cable could be up to 72 μT,
which complied with the ICNIRP limit by large margin of over 25%. Sensitive receivers would be expected to be located on land which are
well beyond 2 m separation from a submarine power cable, and EMF would decrease
rapidly with increasing distance, the EMF due to a submarine cable at any
sensitive receivers on land would be expected much lower than that under water
within 2m from a submarine cable. EMF
compliance to ICNIRP limit at the sensitive receivers would be expected. Hence,
it is expected that no adverse EMF impact to sensitive receivers from submarine
power cables.
15.9.1.5
Nevertheless, the design of the EFs would be
subject to further review by the proponent of the EFs.
Therefore, in view of the uncertainty, the proponent of the EFs would
apply for an EP separately when the design information is available, following the EIAO
mechanism for the construction and operation of the proposed EFs to ensure that
no adverse impact from the exposure of EMF generated from the proposed EFs
would be anticipated.