What does the Energy Transition have to do with Clean Water and Improved Sanitation? Not everyone is as aware as they should be of the challenges many people face in the developing world to have access to clean water and improved sanitation. Many people take these services for granted, not realising this is a struggle for billions of people in the world. In September 2000, the UN issued 8# Millennium Development Goals (MDGs) – MDG7 was “Ensure Environmental Sustainability” and it included the challenge to halve the proportion of the population without sustainable access to safe drinking water and basis sanitation. Some progress was made but these goals needed to be expanded and renewed. In September 2015, the UN General Assembly adopted the 2030 Agenda for Sustainable Development that includes 17# Sustainable Development Goals (SDGs) – SDG6 was “Clean Water and Sanitation”. Most importantly, they challenged us to address these goals holistically. SDG7 is “Affordable and Clean Energy” – the Energy Transition is a key part of this goal and, to be able to deliver many of the other goals, it will be needed. The topic of this article is SDG6 and how improved Electricity access can help.
Some significant international facts and figures about the challenge of SDG6:
- 1 in 4 health care facilities lack basic water services;
- 3 in 10 people lack access to safely managed drinking water services; every day, nearly 1,000 children die due to preventable water and sanitation-related diarrheal diseases; more than 2 billion people lack access to safe drinking water;
- 6 in 10 people lack access to safely managed sanitation facilities; 3-4 billion people lack access to basic sanitation services, such as toilets or latrines;
- Water scarcity affects more than 40 per cent of the global population and is projected to rise. Over 1.7 billion people are currently living in river basins where water use exceeds recharge;
- An estimated 3.6 billion people live in areas that are potentially water-scarce at least one month per year, and this population could increase to some 4.8-5.7 billion by 2050;
- More than 80 per cent of wastewater resulting from human activities is discharged into rivers or sea without any pollution removal;
- Only 5 per cent of arable land is irrigated and to keep up with forecast population growth in Africa, this needs to be increased significantly.
Providing increased access to Electricity can offer help to face these challenges. Existing hydrocarbon resources in many countries with Energy Poverty should be accessed first, as efficiently and cleanly as possible, to begin to raise living standards by providing energy, clean water, and improved sanitation. As economies grow and strengthen, it will be possible to progress further on the Energy Transition with increased use of Renewables. But in the beginning there will also be regional areas with either no existing hydrocarbon resources or else their remoteness and lack of adequate transport means that energy supplies (electricity or fuels) are constrained.
Sources of Water
A comparison of two maps illustrating the availability of aquifer productivity and annual rainfall across Africa shows that in some areas of lower annual rainfall, there may be moderate aquifer productivity to help offset the lack of rain:
The United Nations Environment Programme (UNEP) published Africa Water Atlas in 2010 and much of the information contained in this atlas is still very useful. Their statistics showed that 64 percent of Africa’s population was rural with the majority living on small subsistence farms. 95 percent of sub-Saharan Africa’s farmland relied on rain-fed agriculture. As can be seen in the map above right, some areas have low annual rainfalls, but may have accessible aquifers as shown in the map above left. Electricity would be needed to power borehole pumps to extract this water – and fortunately Solar PV powered pumps are feasible to be used if provided.
Groundwater is a common source of drinking water from isolated and distanced handpump wells, but to be able to increase its use for agriculture is more of a challenge. The good news is that it has been estimated that the estimated volume of groundwater storage is more than 100 times the estimates of current annual freshwater resources in Africa. Resources like the Southern African Development Community (SADC) Groundwater Management Institute(GMI) are available to help plan programmes to develop groundwater resources.
Once a location has been surveyed and potential sources of water identified for access, there needs to be a plan to manage these resources before the corresponding energy requirements can be identified and solutions found. Potential users of the water could include agricultural, residential, commercial, and/or industrial users. Each type of user has different requirements including rates, volumes, and inlet water quality specifications. Also each type of user has different water outlet or discharge characteristics. Some users will have runoffs and some users will discharge wastewater. Some users will be clustered (facilitating combined water systems) whilst other users may be located remote from each other (requiring isolated water systems). A fully integrated water management system can be applied to maximise the water usage and ensure the right type and amount of water is available to each user.
Water sourcing can involve surface water collection from streams or rivers using dams and/or collection ponds. Desalination of seawater is an energy intensive source of water, but Solar PV powered plants are possible. Groundwater collection can involve wells with borehole pumps and reticulation systems to gather the water into the user locations, often with storage reservoirs. Some groundwater may require desalination prior to use due to the presence of mineral salts (e.g. brackish water). Processing would be required to make the water suitable for human consumption, but it may also initially be suitable for some industrial processes. Residential water has been characterised as clear water, grey water, and black water in accordance with generally accepted international usage. Clear water can be potable water ready for human consumption, grey water is some form of waste water from drains that has not had human waste contact, and blackwater is sewage water from human waste contact. Different water treatment technologies and strategies will apply for each type of water. Not all water will be able to be reused and some extremely contaminated wastewaters may have to be left to evaporate in containment ponds prior to processing of remaining solid residue waste (e.g. sludge). In some locations, treated wastewater may be very suitable for agricultural use, either directly or after further processing through “constructed wetlands”. Balancing the requirements of the different users with respect to priorities and water usage sequencing will attract regulatory scrutiny, but cooperative efforts with all users will also improve ESG ratings for Commercial and Industrial users.
Residential / Commercial Water Pumps
- Solar PV powered (Example Project in Syria, 12 no. PV Panels, 30 m2, PVOUT=1826 kWh/kWp, kWp= 3.1 kW, produced summer peak 24m3 water with Borehole Pump (DC)
- Solar PV powered (Example Project in Sudan, 32 no. PV modules, 80 m2, PVOUT= 1899 kWh/kWp, kWp=9.2 kW, produced daily average of 72m3 water with Borehole Pump (6” / 180m / 12 m3/h)
Agricultural Irrigation / Industrial Water Pumps
- Pump sizes can vary significantly based on pump heads, depth of groundwater (e.g. up to 500m), and pumping rates; borehole sizes can vary (i.e. internal diameters from 4” to 10”); resultant pumps can range in motor sizes (i.e. small pumps 0.37 kW up to very large pumps of 220 kW).
Multiple Well Fields
- In some locations, multiple wells may be required to get the supply needed; in this case well spacing is important to help minimise interference between wells – this will affect power distribution to the pumps and reticulation for the water collection;
Wastewater processing can range from residential to commercial to industrial solutions and can either use technology or “Nature-based solutions”. Challenges include degradation of water quality due to nutrient loading (including pathogen loading) and chemical pollution (from processing (especially high concentration pollutants) and other human activities).
Containerised wastewater treatment is available for remote locations (e.g. 75 m3/d) where the entire treatment process including aeration takes place inside a container.
Modular wastewater processing plants are available from small scale residential (e.g. a couple of households) up to small villages (e.g. up to 85 people, 10 m3/d) up to communities (e.g. up to 1250 people, 150 m3/d) up to larger towns (e.g. up to 8300 people, 1000 m3/d).
All these collection and treatment solutions require energy to run pumps and processing equipment. For many locations this energy can be provided by Renewables including Solar PV and Wind Power. Multiple current suppliers of these solutions currently provide good Renewable power options.
“Nature-based solutions” (NBS) involve using green (natural landscape) as opposed to relying solely on grey (constructed) infrastructure. They can complement each other working together. One application of NBS is “constructed wetlands” for wastewater treatment. “Suitable environments for both aerobic and anaerobic microorganisms are present in the wetlands and carry out the biological processes necessary to remove or transform pollutants such as nitrates, phosphates, ammonia, manganese, sulphur, and carbon carried by the water.” Constructed wetlands applications for wastewater treatment have been demonstrated on effluents including petrochemical, dairy, meat processing, factory effluents, and breweries. NBS can also provide additional environmental and socio-economic benefits. Some environmental co-benefits include habitat improvement, carbon sequestration, soil stabilization, groundwater recharge and flood mitigation. Socio-economic benefits include job creation through enhancing economic development with better access to clean water. Some types of pollutants however (especially high concentrations from some Extractive Industry processes) may require some form of pre-treatment using conventional grey infrastructure prior to release of improved wastewater into the NBS systems. Longer wastewater retention times in NBS may also need to be considered in balancing green and grey infrastructure solutions. Using Renewable energy for the grey infrastructure processing combined with low energy NBS solutions helps reduce overall power requirements.
Examples Clean Water and Improved Sanitation
Semi-arid regions with remote communities and subsistence agriculture are facing significant challenges from energy poverty and inadequate clean water and improved sanitation. These challenges have adversely affected the environment (i.e. GHG emissions from carbon based fuels; untreated waste), public health (e.g. unhygienic conditions associated with inlet water and outlet waste), economic development (e.g. lack of power for business), and educational opportunities for young people (e.g. lack of schooling due to time spent on subsistence activities). Increased use of Renewables as part of the Energy Transition will help meet these challenges.
Energy Requirements for Clean Water and Improved Sanitation
Some large population centres and/or commercial or industrial locations may be able to utilise Conventional Power Generation (ideally using Clean Gas (i.e. Pipeline, CNG, LPG, or LNG)) for up to ~15-20 years until scale-up of Renewables allows them to be more widely powered by cleaner energy. Many locations however likely need to begin rapid adoption of Renewables to provide the Electricity needed to help provide Clean Water and Improved Sanitation – especially for remote communities and to help attract business (Commercial and Industrial) to these areas. Many remote, semi-arid regions around the world have good Solar radiation (Photovoltaic Electricity Potential) to utilise Solar PV Power systems able to provide the energy requirements for Clean Water and Improved Sanitation. Solar PV is able to be scaled from individual residence up to utility size systems. The necessary water management systems can similarly be scaled from individual residence up to utility size systems. Commercial challenges can be significant in less advantaged countries, but the world has made a commitment to Sustainable Development for these populations. SDG6 “Clean Water and Sanitation” is able to be well supported by SDG7 “Affordable and Clean Energy” through the Energy Transition use of Renewables and Energy Storage Systems.