Can solar power produce freshwater in the Middle East?

As more desalination plants get built in the Middle East, the need to save the vast amount of fossil fuels burnt every day in powering these plants is greater than ever.

With Concentrated Solar Power (CSP) being a relatively new technology, how feasible will it be to integrate it into the region’s existing desalination plants?

By Heba Hashem 

A harsh water reality

One of the world’s most water-deprived regions, the Middle East and North Africa (MENA) has access to just 1.4% of the earth’s freshwater. And while the average water availability per person across other regions is around 7,000 m³/year, in the MENA zone, it is almost six times less at 1,200 m³/year per person.

With no permanent rivers or lakes and very little rainfall, the region’s desalination accounts for about 38% of global capacity; mostly concentrated in the desert states of the Gulf Cooperation Council (GCC), where water is supplied through surface water extraction, groundwater extraction, conventional desalination and treated wastewater.

“When it comes to groundwater extraction, there are very large groundwater aquifers in the MENA region, which are recharged by rainfall and by incoming rivers. However, most of the water contained in those subterranean basins is fossil water that is not renewed on an annual basis,” explains Karen Stummeyer, Deputy Head of Desalination at Fichtner, who will be speaking at the CSP Today Concentrated Solar Thermal Power Summit in Sevilla on 12-13 November, 2013.

Feasibility of CSP integration

Considering the numerous existing desalination plants in the Middle East, adding CSP systems to these plants may seem as a logical solution for the near term. “In principle, a solar field could be added to an existing power and desalination plant, similar to other solar steam-augmentation projects, as long as the plant has a useful life of at least 15 to 20 years,” explains Stummeyer.

However, she notes that the available land next to existing power and desalination plants is usually limited; thus, the potential for such “brownfield” projects would be rather low. Additionally, there are contractual and regulatory challenges that would need to be overcome.

Manoj Divakaran, founder and president of Empereal, which together with KG Design Services built a fully operational solar thermal desalination plant in Tamil Nadu – the first of its kind in India – believes that the CSP value chain will become much better when thermal desalination is used along with power generation to extend the value of the CSP produced steam.

Many industries, such as textile and chemical plants, already consume large amounts of steam, produced utilising increasingly expensive fuel sources like coal or natural gas; therefore CSP could be used to augment the steam production in such plants. The GCC for example has a strong need for an industrial steam solution for enhanced oil recovery and district cooling.

“There are a lot of advantages, but at the same time, CSP has to overcome its challenge of intermittency. CSP systems can be designed to provide base-load capability, so if you want to integrate industrial plants well, you need to come up with a base-load solution. For example, by having thermal storage, so that you can avoid sudden shutdowns or output fluctuations,” explains Divakaran, who will be speaking at the CSP Today Sevilla Summit 2013.

Hybridization is another advantage to CSP in the Middle East, since combining CSP with natural gas would enable a continuous base-load production. Although hybridization is currently more cost-effective, as thermal storage becomes more efficient and cheaper, it will provide an equally viable alternative.

“One of the most important advantages learnt from our long experience in India is that CSP technologies can become a decentralized source of power for water generation. Tapping the power of CSP in terms of 5 MW or 10 MW systems, along with water desalination, which are decentralized and set up fairly close to the consumer, provides a large advantage. This is especially true when you consider the many islands and remote areas of this region,” highlights Divakaran.

He further notes that a system producing power and water, consumed within a 10-20km radius, would be a model for CSP, which is not feasible with conventional power-generation methods.

“Let’s assume there’s a CSP plant producing power and steam. With that steam you can either set up an MED system very close to the coast where you have seawater, or use the power to run a Reverse Osmosis (RO) system. The RO gives you further flexibility, as you could have the CSP plant built in another location and transport the power, so RO can be set up either far away from the CSP plant or in a stand-alone configuration”.

MED versus RO

RO and MED will be the popular technologies going forward for solar desalination, suggests Divakaran. However, he points out that the CSP-MED combination is especially attractive because it can be used in dual configuration mode; producing both power and desalinated water.

“When you’re in power generation mode in CSP, you need to have a way to condense the steam coming out of the turbine, and if you consider desalination as a way of using that spent steam then it becomes financially attractive. The energy cost of desalination starts to fall, and thereby the cogeneration of power and water in the CSP-MED combination can be economically very attractive”.

The challenge, he notes, is to bring the fast-developing CSP industry into sync with a mature industry. “Desalination is a very mature industry, it’s been around for more than 70 years. And if you look at CSP, it’s a maturing technology, so there’s the difficulty of integrating a technology which is still evolving into a highly developed process, especially in the GCC, where desalination is widely used”.

The Saudi case

Saudi Arabia remains as the largest producer of desalinated water in the world, accounting for at least 17% of total world output. Yet the country is facing water scarcity with the amount of water available per capita per year less than 100m³.

“Except for the mountainous areas in the southwestern part of Saudi Arabia, precipitation is very low and infrequent with extreme variation from one year to the next. Currently, almost 40% of the country’s water production relies on supply through the wells and 60% on desalination,” says Dr. Ibrahim Altisan, General Manager at Saudi Arabia’s Saline Water Conversion Corporation (SWCC), who will discussing industrial CSP applications at the CSP Today Sevilla Summit in November.

Today, SWCC operates 27 desalination stations that produce more than three million m³/day of potable water. With Brent crude currently priced at around $108 per barrel and natural gas at $3.7.MMBtu, burning fossil fuels to power desalination is far from economical.

In fact, a World Bank study found that Saudi Arabia burns around 1.5 million barrels of crude oil every day to produce water through desalination, and that the trend is similar in most GCC countries. Moreover, each barrel of oil burned for local desalination operations, is one less barrel contributing to the national GDP.

Pilot projects crucial

In the next eight years, Saudi Arabia plans to invest $11 billion on desalination. By 2020, the King Abdullah Initiative for Solar Desalination aims to gradually make all desalination plants run on solar power – mainly using RO.

“I think, one of the main restrictions in developing a solar-assisted desalination plant is its expensiveness. Because of its high value which is almost double the cost of conventional systems, such projects are usually done in small scale. We can overcome this dilemma by implementing small projects with economic assessments and reliability tests”, suggests Dr. Altisan.

Similarly, Divakaran notes that pilot projects are “a must to give you a good understanding of local solar radiation and haze factors at sites, before you embark on very large solar projects”.

Although the Saudi solution is desalination on a macro level for a population of 28 million, in Qatar, where 2 million people live, two pilot projects are being carried out. The first, titled DohaSol, is being implemented by Qatar Energy and Environment Research Institute (QEERI) with the aim of setting up a solar-powered desalination plant to generate electricity and produce freshwater.

France’s Sogreah has also been contracted by the state-owned Qatar General Electricity & Water Corporation to conduct a feasibility study for the country’s first solar desalination plant. Although the main technology under discussion is the parabolic trough with MED, Sogreah is yet to conduct further studies to determine the most viable technology.

“When you look to the future, I feel that the current conventional method of consuming fossil fuels for the production of water will definitely be part of future plans, but new plants and growth using this traditional approach will neither be sustainable nor economically viable,” stresses Divakaran.

“The only way CSP can scale up to various industries is by standardization and by creating well-defined interfaces through which other technologies, manufacturers and industries can interact with CSP. I’m very keen to share our experiences at the CSP Today Sevilla Summit 2013”.
 

CSP Today Sevilla 2013

12/11/2013 - 13/11/2013, Sevilla

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