An integrated methodology to measure and verify energy conservation under incentive-based irrigation pumping programmes

Abstract

Water scarcity and droughts have become a looming threat in many counties worldwide. In South Africa, a water crisis is upon the country and estimations show a supply shortfall of 17% by 2030. When considering water consumption per sector, agriculture surpasses all other sectors by far with a global average surface water usage of 70%. Investigations in South Africa, and other countries in the world, have shown that inefficient irrigation water application, over-irrigation and waste are prominent and there is a tremendous potential for conservation. If water can be conserved through irrigation system optimization and efficient irrigation practices on South African farms by only 28%, it can hypothetically fill the 2030 supply shortfall. Alongside water, there is also significant energy conservation potential with investigations showing a near energy use reduction of 40% being achieved. Since there is such a usage improvement potential with both water and energy, conservation attempts are expected to be commonly found with significant impacts achieved. This is however not the case and in general conservation is hampered by a lack of necessary incentives and other obstacles. Incentive vehicles are required to encourage or persuade irrigators to invest in conservation technologies and adopt conservative irrigation practices. Here caution is advised since agriculture is very complex and interwoven, and a mechanism such as water tax can disturb a delicate economic balance which can have many negative interactive effects. A method is required to unlock the conservation potential of the agricultural sector without these risks. The problem is that even if there is some type of water incentive or reduced usage rebate for an irrigator, this is not adequate to fund and sustain efficiency conservation. However, if the benefit from other available incentives, like energy conservation and greenhouse gas mitigation, can be combined with that of water, the goal is much more achievable. A very crucial requirement of incentive mechanisms is proper quantification of the real attained savings. Depending on the incentive mechanism, the savings quantified should adhere to strict regulation and high confidence levels with low error margins. The quantification process goes under many names but will be referred to in this study as Measurement and Verification (M&V). The practice of M&V on irrigation conservation can be very challenging and often discourages or prevents conservation projects even though there are incentives available. In addition, the largest conservation impact in the agricultural sector is distributed over thousands of small irrigation points which cannot justify conventional M&V methods. Another concerning observation is that the combined bottom-up results of electrical conservation projects and programmes, over all sectors, show a significant impact, however, this same impact is not observed higher on the electrical grid. This calls into question both the validity of the M&V results and the effectiveness of the conservation methods implemented. The focus of this study is to overcome irrigation conservation M&V challenges by providing original, practical and cost-effective M&V approaches, methodologies and frameworks that create a novel turnkey solution which can quantify irrigation electrical energy conservation on a project level, programme level and regional level. Although water conservation is evidently of higher importance here, the greater focus is on electrical energy conservation since this, with related incentives, can be utilised to realise water conservation. Thus, the primary aim of this study is developing a novel integrated methodology to measure and verify irrigation pumping energy conservation under incentive-based projects and programmes. Greenhouse gas mitigation can also be directly connected to quantified energy conservation which again opens carbon market offset possibilities. Project level M&V is defined as the full contractual life evaluation of a project making use of full-time metering of key project parameters. Exceptional evaluation difficulties were experienced and cumbersome M&V methodology challenges were encountered with demand-side management irrigation pumping projects part of this study. On these conventional baseline development methods were ineffective and unique M&V methods were devised, developed and implemented. The study also intends to give guidance to M&V entities, project investors and implementers on what is required for proper M&V. Through this, project stakeholders can pre-emptively ensure that the correct mechanisms ME Storm - PhD Thesis - North-West University, South Africa - Nov 2018 orcid.org 0000-0002-1067-1284 Page iii for a successful conservation project are in place. It also gives guidance to ensure that proper M&V is already implemented from the project planning phase. Project level M&V is generally for large projects that can justify high M&V costs associated with full project quantification. However, for programme type irrigation energy conservation rollouts this is not feasible and a programme level M&V method is necessary to quantify impacts. Programme level M&V is defined here as a method of quantification that does not use continuous metering, but incorporates a calibrated simulation model or a deemed savings approach to establish conservation impacts over the programme’s contractual life. One such irrigation programme, the Eskom Standard Product Programme (SPP) in South Africa, is investigated. Unique methods are designed to effectively determine conservative but representative energy efficiency impacts without using continuous power demand profile measurements. The study also focusses on an original calibrated simulation M&V model to establish the available peak load for irrigation load shifting Energy Conservation Measures (ECMs). This approach can determine the available peak period load before any implementation attempts, show the available shiftable load and provide the post-implementation reduction impact that has been achieved. In order to address the problem of bottom-up impacts not being visible on the electrical grid, the study presents a unique regional level M&V methodology that allows M&V assessments and impact validation at a higher level. This can be bound to a certain area, a region or an entire province or country. A regional level M&V methodology has the advantage of providing results quickly and allows for tracking sustainability of savings over time, long after project or programme level M&V has ceased. However, a regional level M&V approach can be very cumbersome and complicated requiring intuitive methods to be successfully implemented and executed. The study discusses an exceptional case study where the regional M&V approach was implemented. This case study did not only draw an M&V boundary around a region, but the entire Western Cape province of South Africa. The study also gives attention to the fundamental aspects that are used to perform M&V, i.e. M&V metering, meter data quality and proper meter sampling. It is regularly observed how the importance of these are underestimated and sometimes neglected. If these fundamentals are not appropriately executed and put into place early, it is found that the M&V of incentive-based projects and programmes encounter disastrous shortcomings with incentive requirements. Proper meter sampling methods are often a significant challenge. Large enough sample groups, improper sampling plans and the difficulties that come with sampling load profiles hinder M&V approaches in attaining high enough confidence levels and low error margins when required. Attention is also given to the design of a simplified sampling concept which reduces load profiles to key single value ratios. After a proper foundation has been established and methods have been developed for project level, programme level and regional level M&V with M&V metering, the study is concluded with an integrated enveloping M&V methodology. Hereby the ultimate goal of realising water conservation in the agricultural sector is focussed on. Integration is done on the following levels: (1) integrating project, programme and regional level M&V to better quantify energy savings for incentive mechanisms such as the SPP; (2) defining water and greenhouse quantification at project, programme and regional level and showing how quantification will be done; (3) integrating this with energy conservation and combined reporting; (4) proposing early integration of M&V into projects, programmes and into policies through which water conservation can be ultimately realised; (5) evaluating the applicability of the South African energy efficiency section 12L tax rebate (Income Tax Act 58 of 1962) to agricultural irrigation ECMs; (6) proposing to enlarge the span and reach of section 12L for irrigation; and (7) providing a framework and conceptual design for a future study to realise this expansion through a unique Agri-M&V approach