Energize RE: Renewable Energy Supplement - June 2015 - Page 64

Private RE Systems

Rooftop solar and own generation takes off in SAby Carel Ballack, PQRS

Most of the public attention to date has been focussed on utility scale PV installations constructed under the REIPPP programme, but privately planned and fi nanced own generation PV systems have shown a sustained and increasing growth in parallel with the government program.

The reasons for this for this are many, the primary being saving of electricity costs. Secondary reasons are security of supply because of uncertainty due to planned load shedding and network failures. Surprisingly, rooftop solar has achieved a “glamour” factor and being "seen to be green" has become a status issue amongst many sectors of the population.

Many of the initial systems as well the larger systems were rooftop based, making use of existing warehouse and factory roofs, although many ground based, especially parking lot and factory storage yard systems have emerged, with the solar PV system proving shade and protection from rain etc. for vehicles and stock stored in the yards.

Private PV (PPV) has been confined mainly to industrial and commercial buildings up to now but there is a growing interest from the residential sector, particularly with the imminent introduction of net-metering.

PPV systems offer an ideal match to commercial and industr ial customers running a single daylight shift, where the main load occurs during daylight hours, and the residual load outside of working hours

is low. Peak solar production will generally coincide with peak workload demand, and with the introduction of time-of-use (TOU) metering, a significant reduction in peak loads can have tremendous financial advantages.

One of the concerns with the growth of the formal and informal industry is the qualification of installers and planners, as well as the quality of installations. Counterfeit panels have already emerged in the bottom end of the market, and poorly designed systems have been encountered [1].

PV industry growth and demand

The known list of privately owned PV (PPV) systems that have been installed and commissioned in SA (Fig. 1) has seen significant growth since Jan 2015. Fig. 1 shows the known grid connected PPV installations as at April 2015, with a total of 416 projects and a peak capacity of 36,5 MW. There are possibly many more unrecorded installations as well as numerous off-grid systems.

The western cape leads with a capacity of 11 632 kW followed by GP with 11 168 kW, although in terms of the number of systems

installed GP leads with 173 projects against WC with 146.

The ongoing list is being created with a number of goals in mind:

Showcasing local privately owned solar PV installations

Data collection

Monitoring growth and development of the sector

Understanding the PV sector in SA (residential and commercial)

Promoting the sector

Training

Showcasing installations

The industry needs to be able to showcase its achievements and what better way than to boast with the number of systems that have been installed. With this we are not claiming that all installations have been fail proof or that installer companies did not end up paying school fees on faulty installations or costly mistakes. Listing systems was not intended to focus on mistakes, but rather on the number of installations that have been done and whether in some way the data could be used to derive a realistic value of the total number of estimated installations locally.

Data collection

The installed base at the time of publication comprised the following features:

94 installations by 34 contractors on systems ≥100 kWp to produce 29,3 MW.

61 installations by 27 contractors on systems 30 kWp – 100 kWp to produce 3,46 MW.

257 installations done by 33 contractors on systems <30 kW contribute only 1,68 MW of the total installed capacity. This represents 4% of installations when measured against listed and installed generation capacity and 62% of the total number of installations.

It could be expected that the solar PV installations in South Africa should form a Fig. 1: Known PPV installations as at April 2015 (Carel Ballack).

Energize RE: Renewable Energy Supplement - June 2015 - Page 65

Private RE Systems

pyramid profile with the larger installations at the top and the smaller installations forming a large base at the bottom. If it is then considered that we currently have a list of 120+ contractors involved with solar PV installations and the above figures are used to determine the total installed capacity, the following estimate could apply:

An average of 7,79 installations have been done by companies in the sub 30 kWp range. If this value is applied over 120 contractors plus additional unlisted installations within the other categories, there could very well be more than 1000 grid tied PV installations in SA producing an estimated 40 MW – 50 MW of energy.

At the time of writing the article there were approximately 415 listed systems which excluded utility scale projects. In essence the 415 systems were primarily grid tied and generated a combined 36,5 MW.

Monitoring growth and development

The public visibility of larger installations at the top tier may be the result of EPC’s marketing and promoting installations through various forms of online and print publications. Smaller contractors have declined to make information available as they are cautious of being reprimanded by utilities for doing illegal installations. Furthermore there are companies who do not wish to disclose activities in this sector for a variety of reasons. It may be of interest to note that newer companies seem to be more successful in securing larger alternative energy projects opposed to companies that have been operating in the alternative energy sector prior to the year 2000.

Understanding the PV sector in SA

The number of organisations interested in the growth and development of the sector is broad based and varies from individuals interested in approaching the sector, academics, industry bodies, international corporations seeking new regions for investment, util it ies, municipalities and suppliers of products to name but a few. Data becomes a barometer for growth and guides industry on further development by providing information that aids an understanding of growth and development patterns within the sector.

Promoting the sector

Graphs and information contained in this article would promote the technology and support ongoing investment by parties

who might not be convinced about the performance of the technology locally.

Training and development

Further to a host of benefits contained in data, only by understanding the growth, development and investment in a particular sector, could the need for training be established. Training when guided by certain standards, forms the backbone of any industry and defines the boundaries to which installations are done and products selected. Skills are transferred to a generation that would see the continued rate of adoption for a specific technology based on solid principles which need to be accepted and understood by industry.

Without the support from industry providing the data would not have been possible and we see new contractors and installations being added to the list weekly. There is no cost for adding systems and it is foreseen that the data currently being collected will have to be submitted to the local municipalities and or Eskom in the foreseeable future in any event as the utilities are considering mapping geo data in order to understand the PV generation load on transformers and infrastructure.

Industry standards

Comparisons can be drawn between the surge in solar water heating installations shortly after the introduction of the Eskom rebate and what can be described as a frenzy in solar PV installations that has taken place since the beginning of 2015 as a result of the re-instated load shedding and power blackouts. The comparisons that can be drawn would relate to the quality of installations and the lack of knowledge by contractors and suppliers, driven by the demand of consumers to have an alternative energy supply. If industry was to adopt any lessons learnt from the solar water heating sector, it would be to define a standard for installations as soon as possible.

This standard is in part being addressed by one of the working groups at the SABS. The standard in question is the SANS10142-3 which covers the way in which inverters will be connected to the grid as well as the required safety measures that would have to be included as part of the embedded generation installation. Embedded generation would refer to any alternative energy installation that would be connected to the grid. In other words, off-grid installations would not be governed by this standard, however adopting some of the installation guidelines might be considered good practice.

Energize RE: Renewable Energy Supplement - June 2015 - Page 66

Private RE Systems

Supporting and enforcing this standard would however not be possible without the introduction of a system whereby the quality of installers and contractors can be measured against specific criteria. Importers to a certain degree are guided by the electrical machinery regulations and requirements by the NRCS on importing electrical goods. Installers on the other hand will have to be managed by a different system. A number of suppliers, contractors and EPC’s have indicated an interest in developing and supporting such an initiative. Three different levels of installer is being considered.

Level Q1 installer

The suggested entry level requirements for a Q1 PV installer will be to have successfully completed three single phase solar PV installations and to have passed an open book written test on solar PV basics.

Level Q2 installer

The suggested requirements for a Q2 PV installer will be to have successfully completed three three-phase solar PV installations and

to have passed an open book written test on solar PV advanced concepts and knowledge.

Level Q3 installer

The suggested requirements for a Q3 PV installer will be to have successfully completed three three-phase solar PV installations with battery storage and to have passed an open book written test on solar pv related DC surge protection, fuse calculation, earthing calculations and advanced PV system design. Although the electrical certificate of compliance (CoC) can be used to ensure the standards are being met, electricians not familiar or comfortable with embedded generation technology being included on the electrical network might just exclude that part of the installation from the CoC. One of the other standards that should be noted for qualification is knowledge of the maximum allowable size PV system for grid tied applications.

Maximum allowable size for grid tied PV systems

Recently numerous articles have been

Number of phasesService circuit breaker size (A)

NMD (kVA)Maximum individual generation limit (kVA)

1 20 4,6 1,2

1 60 13,8 3,68

1 80 18,4 4,6

3 60 and 80 41,4 13,8 (4,6) per phase

Table 1: Maximum sizes for domestic grid tied solar PV systems.

circulated showing ver y good looking residential installations where the contractors have installed fair sized PV systems, most of which have been grid tied. In the absence of standards most contractors have been installing systems sized according to the consumption patterns of the consumer. It should be noted that there is a standard that guides installers and companies selling these systems as to the maximum size systems that can be installed.

The reason for limiting the system size is due to the infrastructure, which comprises the utility supply transformer and cable capacity for the area. In most residential areas, the transformer is shared between a number of properties. Consider that a grid tied system has been installed in a residential area when no load is being drawn by the specific consumer.

Technically this poses no problem as the other consumers situated on the same side of the transformer would consume whatever has been generated by the grid tied PV system and it would have little or no impact on the existing infrastructure.

The situation changes however when a large number, say where 50% or more of the consumers connected to the same transformer have grid-tied systems. In this case the area could experience a rise in voltage potential as a result of the combined PV systems all feeding back into the same network. This is potentially where complications could arise with the current infrastructure not being able to maintain its integrity under the new operating conditions.

According to NRS097-2-3 of 2014, the combined PV system supply should:

Not exceed 25% of the shared transformer capacity

Any generator greater than 4,6 kVA should be balanced across phases

If the maximum individual generation limit is exceeded, the customer could potentially be connected through a dedicated LV feeder, or apply for a larger utility supply circuit breaker

In the case of non-compliance with the above mentioned criteria, where additional generation does not meet the simplified connection criteria; it cannot be connected to the network without further detailed studies. Table 1 gives maximum sizes for domestic grid tied solar PV systems.

Contact Carel Ballack, PQRS, Tel 082 322-2601, carel.ballack@gmail.com

Fig. 2: Capacity installed per region (kW) (Carel Ballack).