4 EvALUAtiON OF SOUtH AFricA’S tEcHNicAL rEADiNESS tO SUPPOrt
4.3 Potential impact on Astronomy
4.3.1 Preamble
This section assesses the risk of detrimental impact by hydraulic fracturing and supporting activities on the SKA radio telescope, primarily located in the Karoo region of South Africa. It builds on two previous reports (Tiplady, 2011; 2012) compiled as input into the 2011 Report of the Working Group of the Task Team on Shale Gas and Hydraulic Fracturing (DMR, 2012).
4.3.2 introduction
The SKA is a highly sensitive radio receiver, typically 15 orders of magnitude more sensitive than a standard cellular phone. When undertaking scientific observations, it will detect and measure extremely weak radio signals that are emitted, through natural phenomenon, from cosmic sources (e.g.
stars, galaxies or hot/cold gas). Consequently, the single largest threat to the successful reception and analysis of these cosmic radio signals, and hence the scientific performance of the SKA, is the unintended reception of radio signals of human origin (referred to as radio frequency interference, or RFI). These can be anything from television broadcast transmissions and local Wifi networks to Bluetooth devices and even the spurious emissions of spark plugs on petrol vehicles. To mitigate this risk, the SKA is to be constructed in the sparsely populated region of the Karoo, where there is typically low demand for such telecommunication services and a low presence of electrical and industrial equipment. The Karoo has already been identified by an international panel as being one of the best locations in the world to host radio astronomy facilities by selecting it as one of two locations to host the SKA radio telescope.
The extreme sensitivity of the SKA means that even the weakest anthro- pogenic radio signals are detectable at some level, and in some part of the radio frequency spectrum across which the SKA will operate. To minimise the potential impact of this risk, careful management and coordination with stakeholders, acting in concert with regulatory and legislative requirements (such as the Astronomy Geographic Advantage (AGA) Act (Act 21 of 2007)), is needed. The establishment of an Astronomy Advantage Area (AAA) (sometimes referred to as a Radio Quiet Zone), protected through the mechanisms of the AGA Act, is in line with accepted practice within the International Telecommunications Union (ITU, 2012).
4.3.3 review of risks
There are two characteristic types of RFI associated with hydraulic frac- turing and supporting activities that pose a detrimental risk to the scientific performance of the SKA:
1 Broadband electromagnetic interference (EMI) – resulting from the use of electrical equipment such as vehicles, arc welders, power generators and information and communications technology equipment. The nature of EMI is such that it is typically weak, but covers a large part of the radio frequency spectrum that will be used by the SKA. As a result, if EMI is detectable by the SKA, it will have an unacceptably high detrimental impact on its scientific performance. However, the source of EMI would usually have to be relatively close to an SKA station to be detectable (<30 km depending on the type of source and the intervening topography).
2 Narrowband RFI – resulting from the use of wireless telecommunication services, including but not limited to inter-device communication such as Bluetooth and Wifi. The nature of this type of RFI is such that it is usual- ly significantly stronger than EMI, but covers a small fraction of the radio frequency spectrum being used by the SKA. Although this can have a lower detrimental impact (than EMI) on scientific performance of the SKA, if there are too many sources of RFI, or the RFI is so strong that it causes artefacts in the SKA receiver equipment (or even damage), the resultant detrimental impact would be unacceptably high.
Both EMI and RFI are expected to originate from a typical hydraulic fracturing site during all phases, from site establishment and construction, to operations and finally decommissioning. This may not be limited to the specific site, but can also arise from increased vehicular volumes along transport routes that may previously have had very low traffic volume densities (and therefore were an acceptable risk to the SKA).
Figure 4-3 shows the SKA Phase 1 and Phase 2 configurations, superimposed over known identified shale gas exploration areas in the Karoo region.
Whilst the layout of the Phase 1 configuration has been optimised and is close to finalisation, the layout of the Phase 2 configuration remains subject to further optimisation by the international SKA Office. The large polygon identifies the Karoo Central AAA, declared by the Minister of Science and Technology in terms of the AGA Act. Regulations promulgated in terms of the Act are aimed at protecting the SKA from detrimental sources of RFI and EMI located within this declared area through a process of assessment and authorisation with restrictions and/or conditions. The central region of the SKA configurations has the highest density of receivers, and is therefore most sensitive to sources of EMI and RFI. Optimisation of the SKA Phase 1 configuration has taken into account the road network and associated traffic volumes in the Karoo region. Whilst low traffic volumes (below approximately six vehicles per day) constitutes an acceptable risk of interference for SKA stations located near (<10 km) the respective road, greater traffic volumes would start to have a detrimental impact on the overall scientific performance of the SKA.
According to Tiplady (2011), the following conclusions were drawn:
1 Based on assumptions made regarding the type of equipment to be used during hydraulic fracturing operations, a buffer zone of 30 km should be adopted around each SKA station, inside which no hydraulic fracturing activities should take place.
Figure 4-3: map indicating the SKA Phase 1 and Phase 2 configuration, superimposed over the identified shale gas exploration areas in the Karoo region
Legend
• SKA Phase 1
• SKA Phase 2 Karoo Central Astronomy Advangate Area Shale Gas Exploration Area roads
Main Secondary
2 A secondary buffer zone of 50 km around each SKA station should be adopted, inside which (i.e. between 30 and 50 km from an SKA station) potential hydraulic fracturing operations should be assessed in detail and, if required, conditions imposed prior to any such activities taking place.
The conclusions reached were limited in the following aspects:
(i) The assessment was based on a limited understanding of the full inventory of equipment to be used, how it will be used, and supporting activities as part of a programme for site establishment, construction, operations, and decom- missioning.
(ii) The assessment was not able to consider site specific details (such as topo- graphical shielding).
(iii) The assessment considered the risk of EMI only in detail. The risk of RFI resulting from the use of wireless telecommunication services would be assessed in accordance with the regulatory framework implemented through the AGA Act if used anywhere within the declared Karoo central AAA. However, significantly increased usage over and above the status quo of class licenced devices (such as Bluetooth transceivers, Wifi networks and consumer communication services) in and around the area may pose significant challenges on the ability of licensing authorities to manage the risk of interference.
A degree of uncertainty was therefore considered in identifying appropriate buffer distances. This uncertainty could be reduced by undertaking the following:
(i) Determination of the full range of equipment to be used, and supporting activities, in the site establishment, construction, operation and de-commis- sioning of hydraulic fracturing sites for each of the various prospective licence applicants.
(ii) Radio frequency measurements and analysis to characterise the EMI from any relevant equipment if no appropriate national or international standards exist. This may require field work at representative sites operated by the licence applicants.
(iii) Determination of a detailed deployment (including site selection) and opera- tions programme, to be used as input into an impact analysis.
A reduction in the uncertainty may, but is not guaranteed to, result in a decrease in the required separation distances for protection against sources of EMI. Assessments for exact locations of hydraulic fracturing sites may also result in decreased separation distances as a result of site specific topographic shielding.
An updated assessment (Tiplady, 2012), undertaken following the SKA site bid announcement in 2012, found no justification for reducing the recommended separation distance (or buffer zone) as a result of the change in the radio frequency spectrum to be used by the SKA in South Africa.
4.3.4 Updated Assessment
As part of this consensus study, an updated assessment of the possible risks of hydraulic fracturing impacting on the SKA project was undertaken and is reported below. The current methodology that has been adopted by SKA South Africa to determine the impact of EMI and RFI sources on SKA stations is aligned with that presented in the previous reports (Tiplady, 2011; 2012). No further detailed information has been made available to SKA South Africa regarding the exact inventory of equipment, and ‘use profile’ (i.e. how the equipment will be used during site establishment, construction, operation and decommissioning) thereof, nor on the de- ployment strategy and supporting activities.
SKA South Africa has compiled a significant body of knowledge on expected emissions from potential renewable energy facilities (solar photovoltaic, solar thermal and wind turbines). Although it cannot be definitive, it is possible to draw some conclusions about emissions and radio frequency propagation from basic industrial equipment. In general, the assessments conducted support the recommendation of a 30 km buffer distance around SKA stations for hydraulic fracturing. This distance could be reduced, but only on a case-by-case basis and following detailed measurements and predictions of expected EMI and RFI from the sites and supporting activities. The scope of supporting activities is not well understood, and remains a critical risk to be mitigated through careful assessment of detailed deployment strategies (of hydraulic fracturing sites). Part of this risk lies in the potential increase of vehicle volumes along transport routes that currently only experience very light traffic volumes, and near which SKA stations are located.
In order to ensure a strong protection regime for the SKA, it is important to preserve regulatory efficiency and avoid complex authorisation processes that could result in competing interests. In that context it would be necessary to ensure that the relevant licensing authority for hydraulic fracturing is required to consider and include relevant protection requirements for the SKA as a condition on the license (or permit). Such a regulatory process ensures that no conflicting permitting conditions arise for the applicant (who may or may not require further permits from other authorities as per the AGA Act and other relevant legislation).
4.3.5 Summary
Hydraulic fracturing operations, including supporting activities, remain a significant risk to the scientific performance of the SKA. Part of this risk is as a result of the uncertainty that arises from a lack of information on specific hydraulic fracturing activities such as deployment strategies, site specific analyses, equipment usage (and characterised in terms of EMI), and supporting activities. As a result, the following proposals are made:
• No shale gas exploration or exploitation should be undertaken anywhere by any applicants within the Karoo Central AAA without formal consent from the Astronomy Management Authority, located within the DST and designated by the Minister of Science and Technology to protect declared areas in terms of the AGA Act and regulations. Such consent may include conditions and/or restrictions, which should be included as a condition on the permit/license issued by the respective authority to the applicant for shale gas exploration and/or exploitation.
• A minimum 30 km buffer distance around each SKA station beyond the Karoo Central AAA and within the Northern Cape province, is proposed. Prior to any proposed exploration and/or exploitation activities by license applicants that coincide with these buffers zones consent should be obtained from the Astronomy Management Aut- hority. Such consent may include conditions and/or restrictions, which should be included as a condition on the permit/license issued by the respective authority to the applicant for shale gas exploration and/or exploitation;
• Prior to any exploration activities commencing, applicants for shale gas exploration in the Northern Cape province should be required to work together with the Astronomy Management Authority to identify exploration sites appropriate both to SKA South Africa and the licence application that would not pose a detrimental risk on the scientific performance of the SKA. The licence applicant shall work together with the Astronomy Management Authority to conduct suitable measurements, as required, to reduce the uncertainty of hydraulic fracturing and supporting activities as noted in this report.