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:
- Light-Emitting Diodes (LED)
- Heat pumps
- Motors and pumps
- Heating, Ventilation and Air-Conditioning (HVAC)
- Cogeneration / tri-generation
- Compressed air systems
- Load management systems
- Waste-heat / Energy recovery systems
- Solar thermal
- Building energy management systems
- 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:
- Chemicals and petrochemicals
- Food and tobacco
- Iron and steel
- Mining
- Non-ferrous metals
- Non-metallic minerals
- Pulp and paper
- Other.
The commercial sector was divided into five main sub-sectors:
- Financial institutions
- Government
- Office buildings
- Recreation and education
- 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).
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:
- Motors and pumps
- Lighting / LED
- Cogeneration / tri-generation
- 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:
- A comprehensive literature review of the best available energy efficiency technologies internationally and in South Africa, including expert interviews
- Scoping of technologies with the most energy efficiency potential
- A detailed assessment of the pre-selected technologies
- Analysis of the main obstacles and stakeholders to the implementation of the pre-selected energy efficiency technologies in South Africa
- Development of initial implementation concepts for the promotion of selected technologies in South Africa.
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).
- Increasing access to affordable energy services
- Improving energy governance
- Stimulating economic growth
- Managing energy-related environmental and health effects
- 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).
| 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.
| 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.
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.
| 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.
| 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.
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.
| 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.
| 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).
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.
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.
| 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.
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.
| 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.
| 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:
- Lack of awareness
- Lack of technologies
- Economics (return on investment)
- Financing
- Regulatory obstacles
- 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.
In terms of the selected technologies, the study confirmed that the focus technologies face fewer obstacles than others, as illustrated below.
Recommendations for energy efficient technology implementation
The study presented an integrated approach to implement selected technologies in sectors with the highest market potential.
