A DSM approach for water usage and electricity costs on water distribution networks

Abstract

Throughout the world – and particularly in South Africa – there is a need to use water more efficiently. Water demand increases, water pollution and climate change are placing our limited water resources under tremendous pressure. South Africa is facing a water deficit brought about by the high water demand and water wastages. This present deficit will have severe consequences across numerous spheres throughout South Africa. The South African government stipulated in the second Nation Water Resource Strategy that various approaches will be pursued as means to reconcile water supply and demand. Amongst others, these strategies include groundwater usage, acid mine drainage water reclamation, desalination, water conservation and water demand management (WCWDM). To date, tremendous strides have been made to promote WCWDM, but without the desired impact. Subsequently, there is a need for a new holistic approach to WCWDM. This must take into account the complex nature of WCWDM and its influences across sectors. Social, political and financial implications have to be considered to guarantee WCWDM objectives. The energy services company (ESCO) model, forming part of the Eskom Integrated Demand Management Programme, has merit and the necessary attributes for reapplication to the water sector. The developed water and energy services company (WESCO) model is proposed for the water sector. The WESCO model as an approach to WCWDM is a novel idea presented in this thesis. This study develops a new approach to WCWDM initiatives in the water sector that is based on the existing ESCO model. Changes to the existing ESCO model, measurement and verification, and framework processes are developed. An avoided-cost value for initiative benchmarking was developed for intervention analysis. This holistic approach includes the water sector necessities of guaranteed savings, auditing, measurement and verification, sustainability and other relevant requirements. This approach also creates opportunities for taxation incentives and rebates, and the stimulation of a WESCO industry. Energy conservation measures, implemented as part of energy efficiency projects, were used as case studies to show the practical implementation of this approach in industry. Indirectly or directly, water is saved during the contract period as a result of various energy conservation measures. From the selected case studies, the impact of these savings on electricity consumption, water consumption and emissions in the water sector are quantified. Over the contract period of five years, Case Study A and Case Study B showed electrical energy, water and emission reduction of 89.492 MWh, 54.823 Ml and 92 176.83 kg CO2 respectively in the water sector. Case study C, which included the initial estimations from an AndroidTM application, which was developed for a different project, showed estimated water savings of approximately 0.183 Ml per day and 67 Ml annually. More importantly, this is an example of the practical and innovative contributions WESCOs can make to the water sector. This study shows that the WESCO model can result in substantial WCWDM savings across different industries and sites. This approach is relevant to the present situation in South Africa as shown with a proven impact