As global water consumption grows and natural supplies reach their limits, Chris Krincevski, ABB Water & Wastewater sales manager, explains why the world must look to desalination.
But first, desalination costs and inefficiencies need to be addressed using contemporary digital solutions.
Data from ‘The World Counts’ suggests that globally we consume around four trillion cubic meters of fresh water a year, and in some regions, agriculture accounts for some 75 to 90 per cent of local consumption.
It illustrates these figures with the fact that 1 ton of grain requires 1,000 tons of water, and a steak requires 1,232 gallons before it even gets to your plate. With a growing population, more intensive agriculture, climate variations and shifting population centres, the United Nation estimates that 30 per cent of the world’s population – across 50 countries – will start to see water shortages.
Even though 70 per cent of the earth's surface is water, only three per cent is freshwater, much of which is in the form of glacial ice. The vast majority of the remaining water is seawater, which is unsuitable for consumption. This scarcity of freshwater, coupled to increased demands on existing water resources for drinking, agricultural and industry means there is growing reliance on alternative sources, with desalination becoming a much more viable alternative, especially when you consider the prevalence of coastal populations.
Western migration
As you can probably imagine – based on their geography and climate – the 10 largest desalination plants are in the Middle East region, in Saudi Arabia, UAE, Dubai and Israel, but with water demand growing in more temperate climates, we could see large plants cropping up in Europe and the Americas too, although possibly not on this scale.
These Western plants need to take a long hard look at their more established Eastern peers to not only extract value and mimic their successes, but also learn from and avoid their mistakes and inefficiencies. And it is this expansion, not necessarily geographically, but in terms of the greenfield clean-slate approach it will deliver, that could bring about some of the largest gains in efficiency.
With a renaissance in control technology and digitalization, these newer plants will have the ability to leverage the enormous potential of digitally transformed operations, which will deliver far faster reactivity and much greater efficiencies.
Even commodity products now deliver operational data and this massive data pool generated by thousands of sensors, valves, pumps, drives and motors will give engineers and analytic systems alike access to unheard of levels data upon which real-time and highly impactful insights can be created.
Indeed, automation and control solutions are now available in building blocks or bundled packages, created specifically for the demands of current and future desalination projects. By having this integration available from the outset, the maximum benefits of an intimately connected solution can be realised much earlier.
More water needs more energy
In technological terms there are two primary types of desalination processes: membrane (or reverse osmosis), which, as the name suggests, uses the principle of osmosis to remove contaminants and impurities by passing the water through a series of semi-permeable membranes. The other type is distillation, which uses heat from a variety of sources to evaporate and then condense water. This comprises three primary methods, vapour compression (VC), multi-stage flash distillation (MSF), and multi-effect distillation (MED). There are many other methods, primarily based around other distillation approaches, but reverse osmosis is by far the most widely used method, in terms of current and future capacity.
The primary issue with any form of desalination is energy cost, which can vary depending on salinity, plant size and the desalination process. To give you an example, in order to supply water to 300,000 people, the Carlsbad desalination plant in California requires the equivalent of a 31.3 MW power plant, which produces enough electricity to power nearly 40,000 average California households for a year.
As expected, the cost of desalination per unit volume of water is currently higher than traditional water sources, but as technology improves, plants are optimized, energy prices come down and greater efficiencies are realized it is expected that these costs will decrease.
Improvements across the board
These efficiencies need to include improved plant productivity; greater sustainability through increasing energy and water efficiency; lowered cost of ownership through simplified troubleshooting and maintenance; improved engineer productivity; shortened start-up and commissioning; empowerment to perform optimal real time control actions and take sound business decisions; and a reduction in the barriers to information sharing, removing the data silos that can cripple large-scale projects.
If you divorce desalination from the equation, the efficiency wishlist above could be applicable for any plant or industry. And this is, indeed, the case. There are multiple success stories from plants around the globe, which are seeing a paradigm shift in operational efficiencies thanks to the introduction of contemporary control, process and automation solutions based around a digitally transformed architecture, and much as the new western desalination plants should look East for inspiration, they should also look all around themselves, at other industries – related or otherwise – to truly see what modern digitalized operations can deliver.
In addition to all the process efficiencies, utility companies and suppliers must also keep an eye on sustainability, which is especially critical considering the cost associated with desalination projects. Indeed, energy consumption has always been a defining factor, even in some legacy projects. Past wins by ABB highlight the performance metrics defined by the operators, which always encompass accuracy-led efficiencies; and as technology evolves, these capabilities are only going to get better as the effects of digitalization percolate into more applications.
Ask any seasoned engineer or plant operator when they should digitalize, and they will reply: “As early as possible”! These new plants are in an unenviable position in that they can exploit the very best technology and domain expertise can deliver, to leverage even greater capabilities from their hardware, processes and employees.
Keppel Marine Desalination Plant, Singapore
Body: Producing up to 30 million gallons of drinking water per day, the flagship desalination project was at the time the most technologically advanced facility in the world.
Operated by Singapore’s national utility company PUB, the plant had to not only be cost effective, but also keep one eye on the future in terms of capacity and demand. ABB was chosen to provide the measurement solutions due to its significant portfolio and domain experience.
This offering included 266 series pressure transmitters, on-line analyzers of conductivity and chemical content, and WaterMaster flowmeters complete with VeriMaster software to ensure enhanced operability and constant availability and accuracy.
SWCC water treatment plant, Jubail, Saudi Arabia
Body: With a daily output capacity of 400,000 m3/day of clean water, the new plant is designed to meet the future water needs of Riyadh and other cities such as Dammam, Khobar and Jubail.
A total of 56 ABB ACS2000 medium-voltage drives were installed, to control the flow rate of pumps, with a typical 30 to 60 per cent savings expected in energy consumption. While improving the efficiency of the entire water cycle, VSDs will also reduce the mechanical and electrical stress on pumps and aeration equipment, significantly