New Ag International JUN/JUL 2020
The Brazilian specialty fertilizer industry is one of the most promising and attractive segments of agribusiness. Despite the adversities and crises of the most varied types in the world economy, the inputs sector continues at an exponential pace of growth and development of new technologies.
According to Abisolo (Brazilian Association of Vegetable Nutrition Technology), specialty fertilizers had revenues of R$ 7.6 billion in the 2018-19 crop, an increase of 19.3 percent compared to the previous cycle. In the 2019-20 season, the entity's expectation is that there will be new growth, between 20-22 percent, to over R$ 9 billion. It proves that these products have gained prominence in Brazilian crops, either as a complement or the main solution for soil nutrition.
Specialty fertilizers have different formulations, developed especially to achieve the specific needs of a crop. This characteristic makes the performance of these fertilizers even better when compared to conventional ones, since they have exactly the macro and micronutrients that plants demands.
In the market, it is possible to find them in special versions for each crop, or in formulas that bring specific nutrients and are suitable for different crops, as with boron, among other elements. The use of this type of solution has been increasingly common in Brazil, both in foliar and conventional fertilization, promoting rapid absorption that, consequently, nourishes the soil and plants with agility. That is, with specialty fertilizers, the right nutrients are offered in the right dose for each crop, correcting deficiencies or even strengthening the crop in an agile and efficient way.
Foliar fertilizers represented 71 percent of total specialty fertilizers revenue, and the largest expansion (23 percent) has been registered in the organominerals segment, but it represents less, only 12 percent of total revenue. This type of technology combines mineral nutrients and organic compounds. The idea of using organic matter is to enhance the efficiency of minerals, improve the use of these nutrients by the soil and, consequently, the yield of the plant in the field.
“Organomineral is a technology that is consolidating itself and the trend is to continue growing more than the others,” says Clorialdo Roberto Levrero, president of Abisolo.
Soy is the locomotive Growth in the use of specialty fertilizers is driven mainly by the soybean crop – the most relevant in Brazilian agriculture. According to consultancy Spark Strategic Intelligence, which researches the market through its Market Nutrition Soybean Panel, this market has become extremely attractive to agribusiness companies – and this has attracted global players in the sector.
According to the consultancy, in recent years there has been significant gains in Brazil regarding the development of technologies for nutrition, leaf and soil segments. Ana Carolina Tisselli, agronomist and relationship manager at Spark, says the foliar fertilizer market is “highly pulverized” in the country. In the records of the Ministry of Agriculture, Livestock and Supply (MAPA), for example, there are more than 250 registered segment companies. Market sources report there are also a large number of manufacturers working in the informal sector. This scenario, according to Spark, contributes to the low knowledge of the producer in relation to brands and products of the genre.
“The soybean farmer receives guidance from private consultants and agronomists from the industry or from resellers to make their decisions,” explains Tisselli. She adds there are large investments by fertilizer companies with a view to launching new technologies, strengthening brands, expanding the offer of services and providing technical assistance to producers. "We will know if the producer perceives, recognizes or values these efforts.”
Tisselli also observes that as in other agribusiness sectors, such as pesticides and seeds, the fertilizer segment has recently registered several movements of mergers and acquisitions of companies.
Market views Eduardo Monteiro, distribution director at Mosaic Fertilizantes, points out the total fertilizer market in Brazil (not only specific differentiated products) should close between 36 and 36.5 million tons in 2019, a growth between two and three percent due to main agricultural commodities soybean and corn. Mosaic Fertilizantes is one of the largest companies in the production and commercialization of phosphate and potassium combined in the world and has a solid presence in Brazil.
Eduardo Monteiro
“There is a strong tendency for companies to look for new solutions so that the producer can increase productivity through premium products that bring benefits to the producer,” says Monteiro. “It is estimated that about 13 percent of the total Brazilian market is for special products. Whoever goes to this line of special products is unlikely to return to the conventional ones because, in addition to productivity, these products add in quality, gains in operational efficiency in the properties and, in some cases, gains in quality in the harvested product, being these motivators for purchasing the product.”
For Thiago Pozzobon, fertilizer manager at Vigna Brasil, despite being a recent market, it has been gaining space year after year, and the current estimate is that it represents around US$1.5 billion. He explains there are several reasons for this expansion, but two are the main ones. The first is the significant increase in the rate of adoption of these products in crops of great economic importance. The second is the constant investment of companies in research and development, and the consequent demonstration of effectiveness in the use of new technologies. Finally, he highlights the constant increase in the area of irrigation and fertigation in which there is a greater demand for water-soluble fertilizers, with a visible increase in productivity in crops when handled with fertilizers of greater agronomic efficiency.
Pozzobon points out the Brazilian consumer currently has a general technical profile, which is why they have been demanding products with proven efficiency. “This implies the selection of companies that have a commercial structure, product and market development teams for the offer, sale and constant monitoring of results and thus guarantee sales growth,” he says.
Vigna has a slightly different profile than other companies, acting more as a regulatory and strategic consultancy. “We offer full support to any and all companies (national or multinational) that wish to operate commercially in Brazil and other Latin American countries, through support in the regulation of the activities of manufacturing, importing and distributing their inputs.”
Maurício Sonda Tonello, from Agrichem's regional market development area, has a similar view. According to Tonello, the market is in full expansion because the industries are investing a lot in technology and are bringing a lot of innovation – which in the coming years will sustain this growth in the long run.
Tonello explains that specialized nutrition has a characteristic of greater refinement in its composition. “They are usually products that have a composition that acts on the plant's physiology and not only on nutritional processes; this is the main factor,” he notes. “Both biostimulants and resistance inducers, with molecules that provide the transport within the plant. All new technologies are being included in this segment today; there is a lot of new things to come on the market and a lot is being developed in research centres that will be great levers for companies.”
Agrichem itself is an example of the changes the market has been experiencing. The company started working in Brazil as an Australian multinational, so it was already operating in the world in more than 50 countries at the time. It came to Brazil close to the 2000s, went through a very strong growth process, was acquired by an investment fund, and received many investments in the industrial and field areas as well. It was recently acquired by one of the largest companies in the world, Nutrien, which is helping to access platforms and research centres worldwide, bringing a very high speed of innovation into the company.
Mauricio Tonello
Tonello has no doubts that Brazil has been leading the market for specialty fertilizers in the world. This occurs, according to him, due to a characteristic of its territory, because it has tropical and subtropical agriculture lands. “This demands a very large amount of nutrients, because our soil is poorer and acidic, and so this characteristic generates demands that many countries do not have due to their natural condition of soil and climate. This will generate leadership in the segment.”
Tonello also notes the products that will stand out the most in specialty fertilizer portfolios are those that solve specific nutrient supply problems for crops. “If there is a demand for a zinc culture, we can supply only and specific with zinc,” he says. “Our products are very concentrated, which facilitates operations on the farm, transportation, and this ends up generating a lower cost for this product at the end. Products that are able to supply the nutrient at the ideal time and for a longer period will be valued, which guarantees more adequate nutrition.”
Production requires nutrition Fernando Dubou Hansel, PhD, is an agronomist from Kansas State University, and conducts research on the management of fertilizers for the productive and sustainable increase of crops. According to Hansel, it is important to note products currently on the market are not the same – the technologies inserted in fertilizers are different. “Nowadays, the most used in the world are simple superphosphates, which are already 400 years old. It is a product that today is used as a source of nutrients and thinks that this is enough.”
However, he says, there are many more needs: first, climate, since Brazil is (mostly) a tropical country, which oscillates has annual rainfall of 1200 mm on average. “All this climatic dynamic requires differentiated nutrients, because the potential for nutrient losses is very large in Brazil,” says Hansel. “Sulphur is one of those ingredients that has a high leaching potential. However, if I work with two sources of nutrients – one that has a higher level of solubility and one that is slower – I will gradually release it during the plant's growth cycle. This is an excellent strategy to improve efficiency in the use of the nutrient.” Hansel adds that when working with two sources of nutrients, there is a maximization of efficiency and minimization of losses.
Hansel also highlights the gain in technology. “Today we have plant genetics with high productive potential, machines that perform the operation with precision, and it is important to emphasize that soil fertilization is the basis of all this. There is no point in having good genetics, which promises to produce a lot, to have excellent phytosanitary protection, to work with precision agriculture, if I do not have a nutritious basis for the crop to express this productive potential.”
In soybeans, for example, in which Brazil has become the world's largest producer, sulphur is essential precisely for the filling of the oilseed's grain. This element, however, has a high level of leaching. “We managed to reach a certain level on this productivity ladder, in this ambition that we have to produce more, with ordinary fertilizers they can only reach a certain level,” says Hansel.
Nitrate-based fertilizers are the most efficient and most reliable nitrogen source available. Thanks to their lower volatilization and lower lifecycle carbon footprint, they also have a significantly lower environmental impact than urea-based products. Numerous trials have exhibited superior performance of nitrates in arable, fruit, ornamental and vegetable crops, with respect to both yield and quality. For arable crops, nitrogen fertilizers containing up to 50 percent nitrate, such as ammonium nitrate and its derivatives, are likely to be the financially optimal choice, due to the relatively low crop value. But for cash crops, especially rapidly growing vegetables and ornamentals, which need highly and readily available nitrogen, fertilizers that contain a high proportion of nitrate-nitrogen generally exhibit superior performance. The most commonly used nitrate-based specialty fertilizers are ammonium nitrate, calcium nitrate, potassium nitrate, sodium nitrate and magnesium nitrate. New Ag International’s Contributing Editor Dr. Oded Achilea describes the virtues of this perhaps overlooked group of fertilizers, including ground-breaking production plants, innovative products and development trends.
Benefits of nitrate-based fertilizers Nitrates are generally very soluble in water. Therefore, they are very easily dissolved by the grower and applied to the soil, readily integrated in it and taken up by the plant roots. Same holds true when the solution is foliar applied.
Nitrates are taken up by the roots as is, and are reduced in the leaves, to be combined with locally produced (by photosynthesis) carbon skeletons to form amino acids. When nitrates are taken up, the plant roots excrete OH– anions to the soil. This is instrumental for plants growing in suboptimal pH soils.
Nitrates are highly compatible with all types of fertilizers and agrochemicals, enabling a wide range of tank mixes. Its innate uptake competition with chloride and boron makes it an effective tool against excessive concentrations of these deleterious species, often found in the soil or irrigation water.
Nitrates are superior to ammonium and ureic fertilizers Ammonium cations are turned into amino acids in the root cells by reacting with the sugars found in the roots. Thus, the amount of sugars delivered to the roots for their respiration is strongly reduced. Hence, the roots will perform worse under sugar shortage, especially under higher temperature, e.g. in tropical climates, and when other strong sugar sinks (e.g. bulking up fruits or tubers) are active. Sugar depletion in the roots increases ammonium concentration in the roots up to a toxic level, which provokes marked plant-scale damages.
Ammonium uptake by the roots also strongly competes with the uptake of potassium, calcium and magnesium.
Unlike ammonium and urea-based nitrogen (N) fertilizers, nitrates are not volatile, so they are hardly lost to the atmosphere. Nitrates are thus more environmentally friendly and feature much higher N-use efficiency. Nitrates' production process produce up to 15 percent less greenhouse gases emissions.
In order to keep electrically neutral, when nitrate anions – which are negatively charged – are taken up, the plant roots need to take up cationic nutrients, such as K+, Ca2+, Mg2+ and most micronutrients. This produces a synergistic nutrition process. However, when ammonium cations are taken up, some of the accompanying anions available in the soil solution are redundant or even deleterious, like SO42–, Cl–, and B3 –.
Nitrate-N is always dissolved in the soil solution, so it is drawn passively into the plant roots, avoiding energy investment. However, ammonium-N tends to adsorb to soil clay minerals, which reduces its availability to the roots.
Nitrate-based fertilizers have some downsides too When nitrates are taken up, the plant roots excrete OH– anions to the soil. This is detrimental for plants growing in sodic and calcareous soils.
Forming always highly soluble salts and being anions which are normally barely adsorbed by soil clays, nitrates are easily lost from the soil by runoff into surface water and by percolation into groundwater. These result in lower nitrogen-use efficiency, economic losses and nitrate pollution of the waterbodies in which they concentrate. On top of this loss, nitrate levels above 10 mg/L (10 ppm) in drinking water are deleterious to infants and can cause the “blue baby syndrome” (acquired methemoglobinemia).
Due to their high oxygen contents, when nitrates are heated, they liberate this oxygen which forms a flammable or explosive mixture when coming in touch with hydrocarbons. This is the reason of being defined as oxidizing substances. Moreover, ammonium nitrate and calcium nitrate are routinely used in the production of explosives. They are, hence, classified under the "5.1" category, under UN Transport Classification, which entails strict precautions that should be taken while transporting and storage of these products. These mandatory procedures increase their transportation and storage costs, as well as making them vulnerable to theft from terrorists.
Nitrates market drivers Worldwide escalating demand for food, due to increasing population, and increasing demand for high-quality foods are main market drivers for nitrates. Similar demand growth is expected for non-food applications such as biofuel, fibre and timber. In addition, continuous reduction in arable and horticultural areas, due to urbanization, desertification and salination, and ongoing reduction in quantity and quality of irrigation water are market drivers for nitrates. Changes in climate and erratic weather, and high uptake and removal of nitrogen by cereals are also market drivers.
Table 1. Principal nitrate fertilizers. / *Year 2017 consumption. Courtesy IFA / Source: CFMW; Customs databases
A rise in the demand for organic produce constrains the use of nitrates. But generally, there is a continuous rise in demand for nitrate fertilizers. Typical CAGR is 3-5.
Ammonium nitrate, the most common specialty nitrate fertilizer AN (ammonium nitrate NH4NO3, 33.5-0-0) is a highly important specialty nitrate fertilizer. Our estimation of AN fertilizers sales volume in 2018 is 29-31 MMMT (million metric tons), and it features some 78 percent of global AN consumption. "Global Market Insight" estimates 2018's total AN market value at $US16.3 billion, with CAGR of 4.5 percent, from 2019, to reach $US23.2 billion in 2025.
In addition to solid AN on its own, there is AN production for calcium-ammonium nitrate, urea-ammonium nitrate, ammonium sulphate-nitrate and NPKs. It is estimated that some 21 MMMT are marketed as solid material, and close to 10MMMT as AN solutions.
Around 20 percent of the AN market serves as a component in the composition of explosives, for mining, quarrying and civil construction projects, and for construction cements. IHS Markit recently stated the leading consumers of agricultural ANs (AN+CAN) in 2019 were Eastern Europe, Western Europe and the United States – together they accounted for about 53 percent of total world consumption. The Russian Federation is the top world AN producing country with roughly nine MMMT, which equates to one-third of the world's AN production.
Being a strong oxidizer, numerous safety regulations are compulsory worldwide for storing and handling AN. It is incompatible with certain compounds, such as combustible substances, chlorate, mineral acids and metal sulphides, and contact can lead to decomposition, combustion or explosion. This is also the reason why many countries and regulatory institutions (e.g. OSHA, EPA and ATF) restrict or even ban its agricultural usage. The restriction is primarily due to possible abuse of the product for production of improvised explosives.
Photo: Erwan Hesry, Unsplash
AN production route The industrial production of AN entails an acid-base reaction of ammonia with nitric acid: HNO3 + NH3 → NH4NO3. This reaction is violent owing to its highly exothermic nature. In order to slow down its field dissolution and leaching, the crystalline product is formulated as prills or granules, and by coating them with an anti-caking compound to reduce its caking under storage.
The 160 MW NOORo I CSP Project is a greenfield IPP and the first of several projects planned by the Moroccan Agency for Solar Energy (MASEN) at the Ouarzazate Solar Complex. www.acwapower.com
AN is a popular fertilizer since it provides half the N in the nitrate form, and half in the ammonium form, thus combining the advantages of both compounds in one application. The nitrate form moves readily with soil solution to the roots where it is immediately available for plant uptake but is also prone to leaching. Some of the ammonium fraction is taken up by the roots and some is gradually converted to nitrate by soil microorganisms. The extremely high solubility of AN (1,900 g/L) makes it very suitable for making solutions for fertigation or foliar sprays. As a nitrogen carrier it is less concentrated than urea (46-0-0), making it disadvantageous from the point of view of transportation. But AN's advantage over urea is that it is more stable in the field and does not rapidly lose nitrogen to the atmosphere. AN is a very popular N fertilizer in the U.S. and Europe, representing 27 percent and 43 percent, respectively, of the total nitrogen fertilizer usage (Grupa Azoty 2016), although it should be said the U.S. number would include AN in UAN solutions.
Potassium nitrate, the cornerstone of water-soluble, Cl-free, specialty fertilizers NOP (potassium nitrate, KNO3, 13-0-46) is a binary fertilizer, composed of the two macronutrients N and K. There are a handful of other binary macronutrient fertilizers but none of them is nitrate-based. Therefore, the demand and production of NOP are increasing at a steep rate. A recent Business Wire report estimates global NOP market growth in additional volume terms at 640,000 MT over a five-year period (2020-2024), progressing at a five percent CAGR.
There have been some recent important developments regarding this product, including a new production plant by Belaruskali and Migao. The production process follows Migao's technology of ion-exchange reaction between AN and MOP. The final first-stage 80,000MT/Y product should be marketed in the domestic market as well as in China, EU, Russia and Turkey. Upon completion of the second stage of this plant, its annual capacity will reach 160,000MT/Y of ag-grade, or 130,000MT/Y of a crystalline product.
Haifa Group has introduced new products, including Haifa Turbo-K (analyses 14-14-17+MgO+S+Fe, Zn; 18-9-18+MgO+S+Fe, Zn; 15-15-15+MgO+S+ME; 12-10-16+MgO+S+ME). These are granular products containing NOP, MgO, S and micronutrients. Unlike bulk blended product, this granular formulation ensures uniform nutrients composition throughout the field. It is designated for open field, rain-fed chlorophobic crops, greenhouses, orchards and turf production. Toll-manufactured in a Balkan country and distributed by Haifa South-East Europe, to supply a specific requirement of the growers in this region.
Haifa Group also introduced Haifa Reci (analysis 13.5-0-46.5), a fully-soluble product for fertigation in greenhouses in countries where it is obligatory to recycle their nutrient solutions applied by fertigation. This product is, therefore, extremely low in sodium (<300ppm), which normally tends to accumulate and concentrate under a fertigation water-recycling regime. Haifa Duo (analyses 15-0-9+21CaO and 14-0-14+18CaO) is a high nitrate, potassium and calcium product, produced by bulk-blending of NOP and CN. Some 95 percent of these products' nitrogen is nitric, while the balance is of an ammoniacal nature. A fertilizer for soil application and fertigation. Other products in this group are markedly enriched with EDTA-chelated micronutrients.
Additional agronomical applications of NOP:
Water-soluble calcium nitrate, indispensable for fertigation CN (calcium nitrate, Ca(NO3)2*2H2O, 15.5-0-0+26.5CaO) is generally produced by applying nitric acid to limestone and then treating the resultant with ammonia to neutralize the acidity. Usage wise, the global CN market is segmented into fertilizers (~50 percent), explosives (second largest), wastewater treatment, concrete manufacturing, latex industry and others. Usage as fertilizers is expected to be the largest and fastest growing segment of the CN market. Global production is in the order of 2.3-2.5 MMMT. Asia Pacific and North America are the largest consuming regions, although its range of applications means that small quantities are consumed by countries across the globe. Yara is by far the major producer in the CN marketplace.
CN is commercially available as crystalline products, mainly Ca(NO3)2*4H2O, and as aqueous solutions containing 45-50 percent Ca(NO3)2. Aqueous CN products have high handling costs in addition to containing much water. Consequently, the logistic costs on nutrient basis are rather high. The crystalline products have poor handling properties with high caking tendency, high dust content and low melting point (43-50 C) preventing CN crystals from bulk handling. The rising demand for food in emerging economies in Asia Pacific and Latin America is positively affecting the CN market. The use of CN in grains and oilseeds is increasing to support the growing demand for wheat, maize and soybeans.
Calcium is an essential nutrient due to its role in stabilizing plant cell walls. Hence, it enhances yield quantity and quality, and prolongs produce shelf life. However, the currently most popular fully soluble CN is markedly hygroscopic and is classified as hazard class 5.1 by regulatory regimes. It is widely applied by fertigation in soil, soilless and hydroponics in greenhouses. On top of its direct nutritional role in plant nutrition, soil-applied calcium improves clayey soil's porous texture, thus boosting soil water holding capacity, and water and oxygen movement in the expanded texture. This also improves soil fertility by releasing cationic nutrients that are fixed within the clay lattice.
The precise analysis of CN is actually {5Ca(NO3)2*NH4NO3*10H2O}. So, apart from nitrate, which serves as its principal N form, it also contains some ammoniacal nitrogen (seven percent of total N) which is harmful for the plant root system, especially at relatively high temperatures and at times of fruits bulking up. These result in reduced yields and quality, particularly in drip irrigated greenhouse grown vegetables, which accumulate sugars in their fruits, e.g. tomato and bell-pepper, but not cucumber. This disadvantage was calling for correction, which was supplied as follows:
Anhydrous CN: In view of the said drawbacks and the remarkable growth potential of CN for arable and horticultural crops, several manufacturers, such as Prayon and Uralchem, came up some time ago with a new, improved product, featuring an analysis of 17-0-0+33CaO. Its most prominent features are the higher CaO contents (an increase of nearly one-quarter) and mere 0.3 percent (w/w) ammonium-N. Additionally, being an anhydride product, it contains hardly any crystallization water which, on the one hand, makes it very hygroscopic, but on the other hand, it also dissolves 3.5-7-fold faster than the standard commercial product. It is, therefore, a fertilizer with much higher nutritional value than the standard one, commanding a justified premium price.
Sodium nitrate has seen better days, but still useful SN (sodium nitrate, NaNO3, 16.5-0-0+36Na2O) saw a considerable demand since the early 1900s as a common source of agricultural nitrates. The world supply of this compound was mined almost exclusively from the Atacama Desert in northern Chile, which made it also known by the names Chile Saltpeter or Chilean Nitrate. But its demand took a nosedive at the turn of the 20th century upon the commercialization of the Haber-Bosch process for ammonia production from atmospheric nitrogen.
SN is a completely water-soluble salt and readily available for plant uptake. It slightly increases soil pH; hence, it is particularly useful for acidic soils. It is easily lost by leaching and denitrification. When large quantities of SN are applied year by year, the nitrate ions are taken up by the crops, while the sodium cations accumulate and negatively affect soil's structure, making it compact and less porous, a process called dispersion.
Its main current agricultural use leans on the specific sodium requirement of a few crops, for example sugar beet, fodder beet and radish. It is the popularity of sugar beet as the main source of the sugar commodity in Eastern Europe that serves as its central market driver in this region. No wonder this is where most agri-grade SN is produced nowadays. Indeed, Poland-based ADOB has a marked line of sodium-nitrate based products, dedicated to this crop, such as the liquid formulated ADOB Na 10% (Analysis 4.5-0-0+13.5%Na+ 0.5B+ 0.05 EDTA-Cu+ 0.2 EDTA-Mn).
It is estimated that some 60 percent of the global SN marketplace is for fertilizer end-use, and the balance is traditionally used in the glass and explosives industry. However, a massive use of tech-grade SN has been developing over the last 20 years, to be utilized in the concentrated solar power (CSP) technology for heat storage.
Magnesium nitrate, a great remedy for acute deficiencies Total international sales volume of MgN (magnesium nitrate Mg(NO3)2, 10.5-0-0+15.6MgO) is estimated at 200,000 MT/Y. This product presents a strong agronomical challenge to the magnesium sulphate commodity. Although both products enjoy very similar Mg contents, MgN features a couple of major advantages, including: 11.5-fold higher solubility (2,200 vs 351 g/L at 25 C); and, nitrate-nitrogen is a much more agile accompanying anion within the plant, thanks to being mono-valent and to having remarkably smaller ionic diameter (Ø=1.73Å) versus the sulphate anion (Ø=2.58Å) present in the magnesium sulphate commodity. The major disadvantages of MgN versus MgS is its remarkably higher price and considerably higher hygroscopicity.
Polish ADOB has developed a special line of MgN products, enriched with different micronutrients, e.g. 10.5-0-0+15MgO+0.08Mn+ 0.05B+0.05Zn+0.02Cu+0.01Mo.
Molten nitrate salts act as a thermal battery Thermo-solar power plants convert the sun’s radiation into electricity. Mirror-empowered concentrated solar power (CSP) is becoming a key technology for clean solar electricity generation. Thermal energy storage (TES) is a tool for bridging the mismatch between daytime solar energy supply and power demand at nighttime and cloudy days. TES, therefore, gives CSP technology an edge over photovoltaic and wind-power plants.
Molten nitrate salts are the most common solution for sensible and latent TES. Molten salts composition is made up of technical grade 40 percent NOP + 60 percent SN, and a modification to this formula is replacing some of them, by CN. This molten salt composition has a specific heat of 1.47kJ kg–1 °C–1, when operating at a range of ~300-560 C. The generated electricity from thermal storage is completely dispatchable and its power can be connected to the electrical grid at any time.
The Andalusian Spanish complex Andasol is currently the world's largest solar power station. It consists of three thermo-solar units which came onstream in 2009-2011. Each unit has an annual net electricity output of 150GWh (1gigawatthour= 1000 megawatthour), and each unit uses two tanks of molten salt as its thermal store. Each tank contains up to 30,000 tonnes of the nitrate’s mixture. It is capable of operating electricity turbines for 7.5h at full load. The Andasol complex cuts carbon emissions in the region by 450,000 MT/Y compared with conventional coal-fired power plants. The lifetime of the entire plant is estimated at 40 years, while that of the nitrate salts is estimated at 30-40 years.
Other worldwide major thermo-solar powerplants using molten salts for energy storage are mentioned in Table 2. It is anticipated that by 2025, the global solar salts demand for CSP could surpass 1 million MT/Y, in the following countries: Spain, Saudi Arabia, South Africa, Australia, USA, Morocco, UAE, Oman, and others.
Table 2. Several leading CSP plants, equipped with a molten salts storage system, and their power prices. / Source: Andasol's website; International Renewable Energy Agency.
