3 PROJECT DESCRIPTION

EGP has proposed the development of a 2x20MW solar photovoltaic (PV) power facility to supply power to the Gold Field South Deep Gold Mine. Photovoltaic Solar Panel technology is being proposed which will occupy up to a maximum of 120 ha (1.2 km2) for the 2x20MW Solar PV Plants.

This chapter provides a detailed description of the proposed Project.

3.1 PROJECT LOCATION

The Project is to be developed on a green field site owned by Gold Fields South Africa located on the Gold Field South Deep Gold Mine property near Westonaria in the Gauteng Province (Figure 3.1). (1) The proposed site is located approximately 50 kilometres south-west of Johannesburg, South Africa. The GPS coordinates are 26°24’44” South and 27°40’ 30” East. The site is located adjacent to existing mining operations. The site has not been used for mining activities or development.

The properties on which the proposed site is located are detailed in Table 3.1.

Table 3.1 Details of the Project Property

Farm Name 347 Doornpoort Portion Number 2,7,12 and 34 Parcel Number SG21 Codes T0IQ000000000347000002

T0IQ000000000347000007 T0IQ000000000347000012 T0IQ000000000347000034

(1) Note that this map depicts the Site Alternatives as discussed in Section 3.7. Site 1 is the preferred site based on the alternatives assessment.

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Figure 3.1 Locality Map

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3.2 THE PHOTOVOLTAIC PROCESS

Solar energy systems produce energy by converting solar radiation into electricity or heat using solar panels. The proposed project will use PV solar technology to generate electricity. The system will be made up of subfields. The PV solar technology chosen for this project consists of the following main components: • Photovoltaic (PV) cell: The PV cell is the device that traps and converts the

thermal energy from the sun into electricity. The absorbed solar energy excites the electrons inside the PV cell and produces electrical energy. The PV cells are usually built with polycrystalline silicon and produce Direct Current (DC). Polycrystalline (multiple silicon crystals) solar cells will be used for this Project.

• PV module and panel: The PV module is the set of interconnected

photovoltaic cells. In the case of crystalline silicon cells, after tests and screening to match the current and the voltage, the cells are interconnected and encapsulated between a transparent front (usually glass) and a support material. The PV module is mounted on an aluminium structure and on a tracker system to track the sun and optimise the capture of energy from the sun. Photovoltaic panels include one or more PV modules mounted as a unit;

• PV array: The PV array is the integrated assembly of modules together

with support structures to form a DC energy production unit; • Inverter: The supply of electric energy to the grid requires the

transformation of PV array DC current into alternating current (AC) by means of an inverter;

• Transformer: The AC current is stepped up to the grid voltage by means of

transformers; and • Substation: Substations typically transform voltage from high to low, or

the reverse. A substation may include transformers to change voltage levels between high transmission voltages and lower distribution voltages, or at the interconnection of two different transmission voltages.

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Figure 3.2 Aerial view of PV Solar Farm

Source: Barry Wiesner

3.3 PROJECT INFRASTRUCTURE

It should be noted that the project description to be included in the EIA will be more comprehensive once the engineering design has been developed further.

3.3.1 PV Technology (module, panel, cell, array)

The PV modules are c-Si (Multicrystalline Silicon) which will be mounted on a single axis tracker. Central inverters with unit transformers will be used and the voltage level is 1500V. The panels will be mounted a 00 angle however the tracking angle will be 450. Table 3.2 illustrates the PV panel datasheet, and Figure 3.3 shows a typical PV Solar Farm.

Table 3.2 PV Panel Datasheet for One 20MW Solar Plant

Item Description Technology Polycrystalline with tracking system N° of cells 72 cells / 3 – bypass diodes Maximum system voltage 1500VDC Nominal Power 315Wp Power Output tolerance Pmax 0% - 3% Maximum power voltage (Vmpp) 36.9V Maximum power current (Impp) 8.55A Open circuit voltage (Voc) 45.4V Short-circuit current (Isc) 9.10A Efficiency (at STC – Standard Test Conditions) 16.26% NOCT (Nominal Operating Condition Temperature)

45°C ±2°C

Mechanical data Dimensions 1956 x 992 x 40 mm

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Item Description Weight 25 kg Source: EGP (2017)

Figure 3.3 Typical PV Arrays

3.3.2 Inverter

Table 3.3 illustrates the indicative specification for the inverter. It is important to note that these are indicative specifications and are subject to change. These will be reviewed and finalised in the EIA Report.

Table 3.3 Indicative Inverter Specifications

Item Description MPPT Voltage Range 925 – 1225 V No of independent MPPT 2 Maximum Open Circuit Voltage 1500V Rated AC Voltage 620V ±10% Rated Output Frequency 50 / 60 Hz (-3 / +2 Hz) Power Factor Circular PQ capability Operating Temperature Range -25 – 62°C Degree of protection Outdoor IP54 Maximum Operating Altitude 2000m Input Ratings Maximum input short circuit current (Isc) 2500A @ 50°C and 2800A @ 25°C PV Voltage ripple <1% Output Ratings Rated output power 1551kVA @ 51°C and 1570 @ 40°C Max. output power at 25°C 1588kVA Rated output current 1444A @ 51°C and 1462A @ 40°C

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Item Description Power threshold 1% of rated output power Total Harmonic Distortion < 3% Inverter Efficiency Maximum efficiency 98.7% EURO 98.5% Dimensions and Weight Inverter Dimensions (WxHxD) 3340 x 2300 x 950mm Inverter weight 2770kg Additional Information Protection against overvoltage DC side: Yes; AC side: optional Maximum RH 95% Non-condensing Cooling Forced air Air flow rate (Max) / MW 5650m3 / h Thermal protection

Integrated, 5 sensors, both on cabinet and power stack

Noise emission @ 1m / 10m 78 / 58 db(A) Power modulation Via remote control (RS485 , Ethernet) and

analog Source: ENEL GP (2017)

Figure 3.4 Typical Inverter Enclosures on site

3.3.3 Transformer

Further details regarding the transformer will be made available during the EIA phase of this Project.

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Figure 3.5 Typical Power Transformer

3.3.4 PV Plant Connection

Power Evacuation

There is an existing 11 Kv emergency overhead power line which connects to both South shaft with Twin shaft. The distance between the overhead line and the solar site is a maximum of 500m. This line is not used as it is an emergency power line. It is proposed that this line be used to supply 20 MW to South shaft and 20 MW to Twin shafts by the solar plant cables “looping in and looping out” of this existing power line. Due to the importance of this line during a power outage, it is anticipated that two ‘loop in, loop out’ tie-in configurations will be used, one for each PV solar plant. This will allow for total flexibility regarding switching. Each PV solar plant can then be isolated when necessary without jeopardizing the emergency line integrity. The emergency overhead line consists of two lines per phase. Each line has a current rating of 650 Ampere allowing for a total of 1300 Ampere (2 x 650).

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The maximum current required to evacuate 20 MVA will be 1050 Ampere, well within the overhead line rating of approximately 24 MVA. Finally, the current capacity of the overhead line is adequate for the required PV plant load (EHL, 2017). Low Flow Options

For the project to be viable, all PV solar plant generated power must be consumed. Each shaft will receive 20 MVA peak generated power during a given day. The installed capacity at South shaft is six by 20 MVA transformers which equals 120 MVA. The installed capacity at Twin shaft is four by 20 MVA transformers and two by 40 MVA transformers which equals 160 MVA. The loading on each transformer is presently assumed to be 50%. At South Shaft, the 20 MVA peak PV solar power will enter the South Shaft Main Consumer substation on, which also has a 20 MVA connected transformer supply from Eskom. At Twin Shaft, the 20 MVA peak PV solar power will enter the Twin Shaft Main Consumer substation, which also has a 20 MVA connected transformer supply from Eskom. It is anticipated that all possible PV solar power plant generated power will be consumed by the shaft by ensuring that the load is always more than the PV solar produced power.

3.3.5 Control System

The plant Control system will be in accordance with EGP specifications and will consist of the following subsystems: • Plant supervisory control and data acquisition (SCADA); • Local SCADA (or Manufacturer SCADA); • Conversion Cabin Control system (remote terminal unit (RTU)/

programmable logic controller (PLC)) (one for each Conversion Cabin); • Power Plant Controller (PPC); and • Trackers Control System. Plant SCADA

The plant SCADA is the main SCADA of the plant. It will perform the control and supervision of the HV Electrical Substation, the monitoring and data acquisition of the HV/MV electrical protection relays, power and energy meters and any other IEDs. In addition it will collect all data from Local SCADA; PPC and Tracker Control Systems, allowing the control of the whole plant and the interface with the local control room and remote control centre.

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Local SCADA

The Local SCADA system, installed in the electrical substation, will collect all the data from the RTU/ PLC in each of the Conversion Cabins and forward same to the plant SCADA. It will acquire and monitor all signals, status and alarms pertinent to conversion cabins and photovoltaic plant field (such as smart string boxes, weather station, transformers, meters). The Local SCADA system will include database management (real-time and historical) of all conversion cabins. Conversion Cabin Control System

Each Conversion Cabin will be provided with a RTU/PLC to provide data acquisition, control and monitoring of equipment at some remote location and to transfer this data back to a master station via a communication system. Power Plant Controller (PPC)

The active power and reactive power delivered by the power plant to the transmission grid will be managed by a dedicated Power Plant Controller (PPC) completely independent from the Local SCADA and based on a PLC hardware/ software system. The PPC will be fully compliant to the specification of the Local Grid Code in terms of guaranteed performance and system response time. The PPC will be able to synchronize all inverters to the grid and to manage the power flow control by means of current-controlled or voltage-controlled strategies. Tracker Control System

The Tracker Control System consists of the following: • Tracker Controllers: one independent PLC based controller for each

Tracker System with back-tracking and wind protection speed (one for each tracker).

• Field Communication devices (e.g. gateways, Ethernet switches), physically located in each Conversion Cabin, which communicate with the several Tracker Controllers and convert the received information to Transmission Control Protocol (TCP)/Internet Protocol (IP) through an Ethernet connection.

The communication between the tracker Controllers and the Field Communication devices can be achieved either by means of a wired or wireless fieldbus architecture.

3.4 PROPOSED LAYOUT AND CONFIGURATION

The plant will consist of 2x 20MW plants each configured as follows:

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315Wp polycrystalline modules mounted on horizontal single axis trackers with a maximum tilt range of 45° in the easterly direction to 45° westerly. The minimum pitch of the trackers is 6m. PV modules will be arranged in 2640 strings of 30 modules each (see Figure 3.6). Power conversion will be done by seven conversion units rated at 3140kVA. Each conversion unit comprises two inverters each with a unit transformer. One plant rated capacity will be 23.246 MW DC / 20 MW AC.

3.5 SECURITY

Security for the solar PV plant will consists of the following general components:

• Fencing around the entire plant; • Security camera; and • Security guards.

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Figure 3.6 Proposed Power Plant Layout

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