Introduction

Since a number of years South Africa has developed a more proactive energy policy in the sense of Energiewende (energy transition) including energy efficiency. Since 2011 Germany and South Africa are accordingly cooperating in the field of energy.
The South African-German Energy Programme (SAGEN) is funded by the German Government and implemented by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) in cooperation with the Department of Energy (DoE) and the South African National Energy Development Institute (SANEDI).
SAGEN in its next phase aims at promoting a few specific, highly promising energy efficiency technologies. In order to make an informed decision on which technologies to promote and support to contribute to electricity savings, SAGEN entrusted DFIC with a study on the potential of energy efficiency technologies.

Scope and methodology of the study

The objective of the study is to identify and analyse which energy efficiency technologies have the most potential for savings, promotion and up-take within South Africa. Only energy efficiency technologies which produce savings in electricity (no fuels) were considered. Therefore the study focused on electricity, excluding boilers, transport and the mining sector.

In a first phase a literature survey and interviews with South African and international experts were carried out in order to structure and focus the technologies. This resulted in 11 pre-selected technologies as follows:

  1. Light-Emitting Diodes (LED)
  2. Heat pumps
  3. Motors and pumps
  4. Heating, Ventilation and Air-Conditioning (HVAC)
  5. Cogeneration / tri-generation
  6. Compressed air systems
  7. Load management systems
  8. Waste-heat / Energy recovery systems
  9. Solar thermal
  10. Building energy management systems
  11. High-efficient building materials.

The aforementioned technologies were analysed in terms of their energy efficiency and energy savings potential generally and specifically within the following sectors in South Africa:

  • Industrial sector
  • Commercial sector
  • Public sector
  • Agricultural sector
  • Residential sector.

The industrial sector was further divided into eight main sub-sectors:

  1. Chemicals and petrochemicals
  2. Food and tobacco
  3. Iron and steel
  4. Mining
  5. Non-ferrous metals
  6. Non-metallic minerals
  7. Pulp and paper
  8. Other.

The commercial sector was divided into five main sub-sectors:

  1. Financial institutions
  2. Government
  3. Office buildings
  4. Recreation and education
  5. Shops.

These sectors hold the following shares of the total South African electricity consumption of 208.9 TWh in 2015 as illustrated below (see: Energy Balance South Africa 2015, DoE, 2018).

Share of selected sectors on the total final electricity consumption in S.A.
Share of selected sectors on the total final electricity consumption in S.A.

In addition to the sectoral classifications, the undermentioned sub-sectors are also of high importance for the four selected technologies:

Buildings

  • Buildings in the public sector, such as government, schools, universities, public hospitals, etc.)
  • Buildings in specific commercial sub-sectors such as office buildings, shops and malls, hotels, private hospitals.

Water & wastewater infrastructure

  • Incl. WWTP of which most belong to the public sub-sector.
  • Agro- as well as food & beverage industry with significant amounts of biowastes and wastewater.

Based on the analysis results of the 11 energy efficiency technologies, four technologies were selected as most promising:

  1. Motors and pumps
  2. Lighting / LED
  3. Cogeneration / tri-generation
  4. HVAC.

The selected four technologies were then analysed in terms of the most relevant sectors, their applications and use, barriers to implementation as well as norms and standards.

In summary, the methodology followed five steps as outlined and depicted below:

  1. A comprehensive literature review of the best available energy efficiency technologies internationally and in South Africa, including expert interviews
  2. Scoping of technologies with the most energy efficiency potential
  3. A detailed assessment of the pre-selected technologies
  4. Analysis of the main obstacles and stakeholders to the implementation of the pre-selected energy efficiency technologies in South Africa
  5. Development of initial implementation concepts for the promotion of selected technologies in South Africa.
The multi-step methodology for selecting energy efficiency technologies
The multi-step methodology for selecting energy efficiency technologies

To frame the study adequately in the South African context, a brief overview on energy policy will be provided below.

National energy policy

The Energy White Paper is the premier policy document on which all policies, plans, strategies and legislation, pertaining to the energy sector in South Africa, are based in the context of national reconstruction and development (post the apartheid era).

The policy has 5 strategic objectives (see: White Paper on Energy Policy of the Republic of South Africa, DoE, 1998).

  1. Increasing access to affordable energy services
  2. Improving energy governance
  3. Stimulating economic growth
  4. Managing energy-related environmental and health effects
  5. Securing supply through diversity.

The above objectives form the basis for the vision and objectives for all other subsequent energy-related policies and strategies in the country, such as: The National Energy Efficiency Strategy (NEES), The Integrated Resource Plan (IRP) and the (EEDSM) Programme (amongst others).

The National Energy Efficiency Strategy (NEES)

The overall proposed economy-wide and sectoral EE targets in the Draft Post-2015 NEES released in December 2016 are presented below (see: Draft Post-2015 National Energy Efficiency Strategy, DoE, 2016).

Table 1    Energy efficiency targets in the Draft Post-2015 NEES
Sector Overall expected 2030 impacts
Economy-wide 29%
Industry 15%
Residential 33%
Commercial 37%
Public 50%
Transport 39%
Agriculture 30%

Energy efficiency and savings potential of selected technologies

The following section will briefly present key facts about selected technologies and their estimated energy savings potential per sector.

Lighting/light-emitting diodes (LEDs)

Energy efficient lighting is one of the most common starting points for many energy consumers when considering the implementation of energy efficient technologies in their homes or work spaces (across all sectors). What is probably more important than the lighting source (lamp) itself is the way in which a lighting system is designed and controlled. Promotion of LED’s should therefore take issues such as system design and control into consideration.

Table 2    Key facts LEDs (see: Accelerating the Global Adoption of Energy-Efficient Lighting,
U4E Policy Guide Series, United Nations Environment Programme (UNEP), 2017
Parameter Value
Application focus All sectors
Typical LED sizes 3 mm -10 mm (5 mm most common)
Typical lifetime ~13 years (if used for 10 hours a day)
Average operation hours ~50,000 hours

Despite the fact that previous promotional activities focused on energy efficient lighting, the study found significant potential to affect energy savings in various sectors in South Africa, depicted below.

LEDs energy efficiency potential in different sectors in South Africa
LEDs energy efficiency potential in different sectors in South Africa

Motors and pumps

Electric motor and pump systems account for about 60% to 70% of industrial electricity consumption and about 15% of final energy use in industry worldwide. It is estimated that full implementation of efficiency improvement options could reduce worldwide electricity demand by about 7%. Electric motors drive both core industrial processes like presses or rolls as well as auxiliary systems such as compressed air generation, ventilation and air conditioning as well as water pumping.

Table 3    Key facts motors and pumps
Parameter Value
Application focus Industry, Commercial sector incl. Wastewater Infrastructure
Pumps and drives sizes up to 3,500 kW
Share of electricity consumption ~60-70% (Industry)
Typical technical lifetime ~15 years (depending on full load hours)

Internationally the following characteristics and benchmarks for compressed air systems can be achieved through BAT. The undermentioned efficiency gain potentials may vary significantly depending on the compared / installed motors and pumps technology.

Table 4    BAT Benchmarks for motors and pumps (see: Energy Efficiency in Electric-Motor-Systems, UNIDO, 2012)
Parameter Value
BAT overall pumps
and drives efficiency
31%
95%
Potential efficiency gains system up to 50%
Efficiency gains through hardware up to 10%
Efficiency gains through techniques up to 40%

The study estimated significant potential energy savings that could be achieved through energy efficient motors and pumps across sectors in South Africa, as illustrated below.

Energy savings potential of motors and pumps in various sectors of South Africa
Energy savings potential of motors and pumps in various sectors of South Africa

HVAC (as part of cooling and refrigeration)

Heating, Ventilation and Air Conditioning systems (HVAC) regulate the quality of the air in a building by means of temperature and humidity controls, which are set to user-defined conditions. These systems are prevalent in the building sub-sector, primarily within the residential, commercial and public sectors, but are also widely used in the industrial sector to control certain process conditions. The useful-energy derived from these systems can be used for space-heating, space-cooling and refrigeration.

Table 5    Key facts about HVAC systems (see: Commercial HVAC Components brochure, 2017;
High Efficiency Commercial Air-conditioning and Heat Pumps Initiative, CEE, 2016)
Parameter Value
Application focus All sectors
Mainly commercial, industry and residential
Typical HVAC sizes Up to 10 MWel (large industrial systems)
18 kWel – 220 kWel (air-cooled chillers)
Up to 2 MWel (water-cooled chillers)
Typical technical lifetime ~20 years (depends on individual components)
Average operation hours Variable, depends on size of building / facility and local climate

HVAC systems vary widely in terms of the individual components making up the system and subsequently how the system itself is set-up in a building and/or tailored to certain (industrial) processes. The type of HVAC system is largely dependent on the functional hardware it uses for heating, cooling and/or refrigeration. Furnaces, boilers or heat pumps can be used for heat generation, while cooling and refrigeration can be achieved through either electrically powered air-cooled chillers, water-cooled chillers or heat driven absorption or adsorption chillers.
The potential energy efficiency measures for pumps and drives with estimated efficiency gains are illustrated below.

Table 6    EE measures for HVAC units (see: Commercial HVAC Components brochure, 2017;
High Efficiency Commercial Air-conditioning and Heat Pumps Initiative, CEE, 2016)
  Measure Improvement COP
Cycle improvements Inverter/variable speed Compressor
Heat exchanger
20 – 24.8 %
6.5 – 18.7%
9.1 – 28.6% (SEAD, 2013)
Parasitic losses EU: Standby
Crankcase heating and control
0.8 – 9% (lower capacity, higher savings) (Armines, 2009)
9.8 – 10.7% (SEAD, 2013)
Refrigerant HC 4% (park et al., 2007) up to 30% (Wang et al., 2004)
Change in use Occupancy sensor  

 Key steps to improve HVAC system efficiency are illustrated below (see: Commercial HVAC Components brochure, 2017; High Efficiency Commercial Air-conditioning and Heat Pumps Initiative, CEE, 2016; Heating, Ventilation and Air Conditioning -Technology Overview, 2011, Carbon Trust).

Key measures to increase the energy efficiency of HVAC systems
Key measures to increase the energy efficiency of HVAC systems

The study identified the commercial sector as having the highest potential for energy savings emanating from HVAC systems. The potential is illustrated in the following.

HVAC potential in different sectors in South Africa
HVAC potential in different sectors in South Africa

Co-generation and Tri-generation

The potential of cogeneration from biogas at wastewater treatment plants was recently assessed in a comprehensive and systematic way by GIZ (2016). In this study 130 plants were assessed with 87 having technical biogas potential and 39 having economically feasible biogas potential. The following table summarises the identified potential through the assessment.

Table 7    Assessed power generation potential from sewage gas (see: A Survey of South African Wastewater Treatment Works, GIZ, 2016)
  Total plant capacity
in ML/d
Electrical energy generation potential
in MWel
Thermal energy generation potential
in MWth
Electrical energy saving potential in MWhel/a
Total “sewage” cogeneration potential (WWTW > 10 ML/d) 5,499 61.37 67.51

537,601
Total existing infrastructure generation potential 4,453 33.37 36.71 292,321
Total feasible generation potential 3,523 27.15 29.86 237,834

The study investigated technologies with the highest energy efficiency potential and estimated energy savings potential. Biogas cogeneration, VSDs, pumps, control systems, process and measurement and management (as an integrated function) were the technologies considered to have the highest energy efficiency potential in the water and wastewater sector in South Africa. It is important to note that nominated technologies, which are closely related in the filtration and especially in the aeration category due to their heterogeneity and diversity of technologies in the plant segment, were not grouped, which could leave a misleading impression that energy efficiency and aeration has little potential. The technologies with the largest estimated energy savings potential were biogas cogeneration and VSDs for motors and pumps as well as the combination of control system, process alignment, monitoring and management. The figure below shows the estimated minimum, average and maximum energy savings potential of the technologies.

Energy savings potential of the main technologies nominated from survey
Energy savings potential of the main technologies nominated from survey

The table below lists the potential electrical energy savings through specific interventions and translates them into equivalent power generation capacity. It makes clear that significant electricity savings can be realized particularly in water supply treatment and aeration in wastewater treatment.

Table 8    Electrical energy saving translated into equivalent power generation capacity
Water life cycle stage Electrical energy savings
[MWh/a]
Equivalent power generation capacity
[MWel]
  Worst case Best case Worst case Best case
Water supply – extraction pumping 0 * 221,400 0 * 25.3
Water supply – treatment 73,800 319,800 8.4 36.5
Water supply – distribution pumping 0 * 172,200 0 * 19.7
Wastewater – treatment aeration 112,321 1,010,866 12.8 115.4
Total 186,121 1,724,266 21.2 196.9

* No energy saving potential, if there isn’t pumping required.

The table below summarises the accumulated energy savings from case studies analysed. The identified equivalent power generation capacity is decentralised savings and can replace larger centralised power generation capacities as transmission losses and other inefficiencies in the overall energy systems do not have to be taken into account as well. These already significant numbers are only a portion of the suspected energy efficiency potential calculated but demonstrate that significant results are achievable also in South Africa.

Table 9    Summary of accumulated saving potential from reviewed case studies
Source Electrical energy savings
MWh/a
Equivalent power generation capacity
MWel
Watergy case studies 1998 – 2005
204,400
23.2
Case studies WRC
135,062 15.4
Assessed power cogeneration potential from biogas
237,396 27.1

Obstacles to energy efficient technology implementation

To investigate the obstacles preventing the large-scale implementation of energy efficiency technologies, the study identified the following key obstacles:

  1. Lack of awareness
  2. Lack of technologies
  3. Economics (return on investment)
  4. Financing
  5. Regulatory obstacles
  6. Lack of skills

Data analysis showed that the lack of awareness, economics, financing, and a lack of skills were considered to be the main obstacles impeding the implementation of the pre-selected energy efficiency technologies as illustrated.

Average number of responses per obstacle from expert interviews
Average number of responses per obstacle from expert interviews

In terms of the selected technologies, the study confirmed that the focus technologies face fewer obstacles than others, as illustrated below. 

Average number of obstacles associated with each technology based on responses from expert interviews
Average number of obstacles associated with each technology based on responses from expert interviews

Recommendations for energy efficient technology implementation

The study presented an integrated approach to implement selected technologies in sectors with the highest market potential.

Recommendations for energy efficient technology implementation
Recommendations for energy efficient technology implementation

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