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Category Archives: Clean energy

There is likely to be a dramatic change in energy landscape with introduction of super critical CO2 power cycle. It not only increases the power efficiency, reduces the foot print considerably, utilizes part of CO2 emission internally in the form of super critical fluid and open a new path to eliminate Carbon emission completely (zero Carbon emission). It also reduces the water consumption in power generation unlike current conventional Rankine cycle power plants. We will soon be able to continue to generate base load power using fossil fuels with zero carbon emission. Unlike Carbon capture and sequestration already tried unsuccessfully in many parts of the world, Carbon capture and recycle will open a new chapter in the history of power generation. By capturing carbon in a solid form with potential industrial applications such a possibility is now within our reach. It means utilization of existing fossil fuel based power generation infrastructure without any Carbon emission and continue to generate continuous power to meet the increasing demand at a reasonable cost. The current focus on renewable energy will continue but until a practical and viable energy and mature storage technology is developed the renewable energy will have uncertainties. Whatever may be the case the overall cost of energy is likely to go up.

Introduction of Oxy combustion in natural gas turbine has eliminated the oxides of Nitrogen from flue gas thus facilitating separation of CO2 from water and recycling water vapour into combustion process. The condensate from gas turbine is a by-product. Despite the usage of CO2 in the form of super critical fluid there is still an excess CO2 to be disposed of.

A conceptual design to capture CO2 and convert them into SNG while generating additional power using the superheated steam obtained as a by-product of methanation has created a new opportunity to achieve zero carbon emission.

It is an exciting development and our company is now in an advanced stage of developing and commercializing such a technology.

Our new reformation process of natural gas using the captured CO2 and steam allows to precipitate Carbon in a solid form. The chemistry of the process can be explained by the following final methanation process using a proprietary catalyst involving few steps.oxy-fuel-directly-heated-sco2-power-cycle-flow-diagram-1sco2-power-cycle

3CH4 +CO2 +H2O ——–> 2CH4 + 3 H2O + 2 C which will take a final form as follows:

CH4 + CO2 ——> 2H2O + 2C

The superheated steam generated in the process can be exported to generate additional power while the condensate water can be exported and recycled. By using an excess of natural gas the captured CO2 is converted into SNG (synthetic natural gas) which can be recycled into the gas turbine thus achieving a zero-carbon emission while continuing to generate base load power. Such a technology can easily be integrated with other sources of energy such as solar, biomass, waste heat and nuclear.

 

 

Carbon emission is a matter of great concern to all the countries around the world due to the global warming and climate change. After the Paris talks many countries are genuinely trying to reduce their emissions either by switching over to renewable energy or cutting down their emissions by reducing their Carbon footprint. In their desperate measure to reduce Carbon emissions some countries like Canada are trying to accelerate carbon emission reduction by promoting innovation technologies with millions of dollars of grant money. Recent fires in the state of Alberta, rich in oil sand deposits have opened the eyes of the world to witness how a disaster can unfold so quickly and   thousands of people to be evacuated in a short notice. Many fled their homes leaving behind their valuables and memories. It was one of the worst fire disasters in recent memory. Canada especially the state of Alberta is now all the more determined to avert such incidents in the future but also equally determined to reduce their Carbon emissions. The fire is due to dry conditions due to global warming and accelerated by oil sands. It is a perfect recipe for a disaster.

Many countries have switched over from coal to natural gas as a cleaner fuel to reduce their Carbon emission. Natural gas emits less CO2 compared to coal. But does it help combat global warming? One has to compare the two different fuels and their combustion by the following reactions:

C + O2 —->  CO2

CH4 + 2O2 ——>  CO2 + 2H2O

Combustion of coal requires less Oxygen (air) when compared to combustion of natural gas which requires twice the volume of Oxygen (air). Coal combustion emits oxides of Nitrogen and Sulphur apart from CO2 and a minor quantity of water vapour and particulate matters. Combustion of natural gas releases twice the volume of water vapour apart from oxides of Nitrogen and sulphur.

Recent findings by NASA confirms that water vapour is the major greenhouse gas apart from CO2 that is responsible for warming globe and the climate change. Therefore, natural gas does not help combating global warming and climate change.

The following excerpts from NASA highlights this fact

Water Vapour Confirmed as Major Player in Climate Change

Credit: NASA

The distribution of atmospheric water vapour, a significant greenhouse gas, varies across the globe. During the summer and fall of 2005, this visualization shows that most vapour collects at tropical latitudes, particularly over south Asia, where monsoon thunderstorms swept the gas some 2 miles above the land.

Water vapour is known to be Earth’s most abundant greenhouse gas, but the extent of its contribution to global warming has been debated. Using recent NASA satellite data, researchers have estimated more precisely than ever the heat-trapping effect of water in the air, validating the role of the gas as a critical component of climate change. Andrew Dressler and colleagues from Texas A&M University in College Station confirmed that the heat-amplifying effect of water vapour is potent enough to double the climate warming caused by increased levels of carbon dioxide in the atmosphere.
With new observations, the scientists confirmed experimentally what existing climate models had anticipated theoretically. The research team used novel data from the Atmospheric Infrared Sounder (AIRS) on NASA’s Aqua satellite to measure precisely the humidity throughout the lowest 10 miles of the atmosphere. That information was combined with global observations of shifts in temperature, allowing researchers to build a comprehensive picture of the interplay between water vapour, carbon dioxide, and other atmosphere-warming gases. The NASA-funded research was published recently in the American Geophysical Union’s Geophysical Research Letters.

AIRS is the first instrument to distinguish differences in the amount of water vapour at all altitudes within the troposphere. Using data from AIRS, the team observed how atmospheric water vapour reacted to shifts in surface temperatures between 2003 and 2008. By determining how humidity changed with surface temperature, the team could compute the average global strength of the water vapour feedback.

“This new data set shows that as surface temperature increases, so does atmospheric humidity,” Dressler said. “Dumping greenhouse gases into the atmosphere makes the atmosphere more humid. And since water vapour is itself a greenhouse gas, the increase in humidity amplifies the warming from carbon dioxide.” Specifically, the team found that if Earth warms 1.8 degrees Fahrenheit, the associated increase in water vapour will trap an extra 2 Watts of energy per square meter (about 11square feet)
“That number may not sound like much, but add up all of that energy over the entire Earth surface and you find that water vapour is trapping a lot of energy,” Dressler said. “We now think the water vapour feedback is extraordinarily strong, capable of doubling the warming due to carbon dioxide alone.”
Because the new precise observations agree with existing assessments of water vapour’s impact, researchers are more confident than ever in model predictions that Earth’s leading greenhouse gas will contribute to a temperature rise of a few degrees by the end of the century.

The amount water vapour released by burning natural gas is twice the volume of natural gas burnt. A plant using 10,000 m3/day natural gas can release 20,000m3/day water vapour that can be recovered. In fact, if the Gulf countries can recover water from exhaust of their gas fired power plants they may not require any water by desalination of seawater at all. Current consumption of natural gas world-wide exceeds 3.5 trillion cubic meters which roughly translates to 7 trillion cubic meters of water vapour into the atmosphere. Such a large volume has a potential to change our climate system.What goes up as water vapor has to condense into water and has to come down ! It will causes flash flooding in many parts of the world which we are now witnessing.The economic loss by such natural disasters will run into several hundreds of billions of dollars in the future.

It is interesting to examine how the state of Alberta is trying to reduce their carbon emissions by promoting innovative technologies. Majority of the proposals are supposed to convert CO2 emissions into “a useful product” so that the emission can be curtailed or reduced. A quick glance on the list of the proposals they have funded so far indicates they will convert CO2 into an industrial chemical such as Methanol or a Fertilizer such as Urea or alkaline chemicals such as bicarbonates and calcium carbonates etc. Can they really solve the problem of carbon emissions by turning them into useful products? The answer is most likely no. It will help capture CO2 at Alberta but it will be released somewhere else where the end products are used.

Water vapor distrubutionClimate variation due to water vapor It will simply shift the problems of Carbon emission from Alberta into some other region of the world. For example, Urea synthesised from captured CO2 will again be released into the atmosphere when Urea is used by farmers. An enzyme in the soil will release the CO2 from Urea into the atmosphere.

The only real solution is to convert captured CO2 back into a fuel such as SNG (synthetic natural gas) so that it can be recycled into the power plant. By this way the CO2 emission will be converted into solid Carbon.

One need not bury CO2 under the ground or emit it into the atmosphere but constantly recycle into SNG so that power plant can generate power continuously without emitting any greenhouse emissions. To do this we need Hydrogen. At present Hydrogen is produced commercially from natural gas but with carbon emission. Other methods of producing Hydrogen without carbon emissions are expensive. But Hydrogen can be generated from natural gas without Carbon emission and it can be used to convert captured CO2 from power plants into SNG. In other words, two greenhouse gases namely CO2 and methane (CH4) will be reacted to generate commercially valuable Carbon nanotube as a main product as shown below. This high temperature reaction can generate superheated steam that can generate power while a valuable solid Carbon is regenerated. Such a process is still in a developmental stage but has a potential to become a commercial reality in the near future.

CH4 + CO2 —>  2C + 2 H2O

In fact, the carbon emission is converted back into a solid Carbon. The Carbon is to return to Carbon to avoid GHG emission (CO2, N2O, NO2 and H2O) that is changing our climate.

The climate is changing and the impact of such a change is felt almost in every sphere of life around the world especially in countries like India.

” Erratic monsoon rain patterns have left crops parched, jeopardizing India’s nearly $370 billion agricultural sector and hundreds of millions of jobs.  Drought conditions are crippling vast swaths of India’s farmland as the country faces its driest monsoon since 2009. With more than 60 percent of India’s agriculture reliant on monsoon rains, farmers are highly vulnerable to changes in rainfall patterns and rising global temperatures, the Indian Council for Research on International Economic Relations found in a report” according to the International Business Times.

The situation in Australia is no different from India, both surrounded by ocean of water yet no water to irrigate or even to drink. Many scientific studies have clearly highlighted the close relationship between warming earth, increasing salinity of seawater and the climate change. But new coal-fired power plants and seawater desalination plants are set up almost every year in these countries. Both greenhouse gas and the increasing salinity of seawater will only contribute to intensify further warming of the earth. There is some awareness about the global warming by GHG (greenhouse gas emission)but there is no awareness about the increasing salinity of seawater. One of the largest desalination plant set up in the state of Victoria in Australia is idle for so many years yet unable to supply water to struggling farmers in the country Victoria. In a way it is a blessing in disguise because it would have otherwise discharged billions of cubic meters of RO concentrate with toxic chemicals into bass strait.

California law requires that any “new or expanded coastal … industrial installation using seawater” must utilize “the best available site, design, technology and mitigation measures feasible … to minimize the intake and mortality of all forms of marine life.” (California Water Code section 13142.5(b)

The following excerpts from NASA highlights the close relationship between

Ocean salinity and changing climate and rainfall.

“Salinity, Ocean Circulation & Climate

 Surface winds drive currents in the upper ocean. Deep below the surface, however, ocean circulation is primarily driven by changes in seawater density, which is determined by salinity and temperature. In some regions such as the North Atlantic near Greenland, cooled high-salinity surface waters can become dense enough to sink to great depths. The ‘Global Conveyor Belt’ visualization (below) shows a simplified model of how this type of circulation would work as an interconnected system.

The ocean stores more heat in the uppermost three (3) meters than the entire atmosphere. Thus density-controlled circulation is key to transporting heat in the ocean and maintaining Earth’s climate. Excess heat associated with the increase in global temperature during the last century is being absorbed and moved by the ocean. In addition, studies suggest that seawater is becoming fresher in high latitudes and tropical areas dominated by rain, while in sub-tropical high evaporation regions, waters are getting saltier. Such changes in the water cycle could significantly impact not only ocean circulation but also the climate in which we live.

‘The Global Conveyer Belt’  (http://science1.nasa.gov/media/medialibrary/2013/05/20/thermohaline_assembled.) represents in a simple way how currents move beneath the wind-driven upper ocean. This movie begins by focusing on the North Atlantic east of Greenland, where cold surface waters get saltier due to evaporation and/or sea ice formation. In this region, surface waters can become dense enough to sink to the ocean depths. This pumping of surface water into the deep ocean forces the deep water to move horizontally until it can find areas where it can rise back to the surface. This very large, slow current — estimated to be on the order of 1000 years to complete a full circuit — is called the thermohaline circulation because it is caused by temperature (thermo) and salinity (haline) variations. Credit: NASA/GSFC

Launched June 10, 2011, aboard the Argentine spacecraft Aquarius/Satélite de Aplicaciones Científicas (SAC)-D, Aquarius is NASA’s first satellite instrument specifically built to study the salt content of ocean surface waters.

Salinity variations, one of the main drivers of ocean circulation, are closely connected with the cycling of freshwater around the planet and provide scientists with valuable information on how the changing global climate is altering global rainfall patterns.

The salinity sensor detects the microwave emissivity of the top 1 to 2 centimetres (about an inch) of ocean water – a physical property that varies depending on temperature and saltiness. The instrument collects data in 386 kilometre-wide (240-mile) swaths in an orbit designed to obtain a complete survey of global salinity of ice-free oceans every seven days.”

According to a new report on desalination in California

Desalination is the removal of salts from saline water (brackish or seawater) using distillation or membrane separation technologies in most cases. Current desalination technologies produce a toxic concentrated brine discharge that contains all the salts and dissolved solids along with process chemicals.

Putting the brine “cocktail” back into the ocean damages the marine environment and runs counter to the environmental goals of the state. The brine creates extensive damage in the ocean in areas sometimes called dead zones. The damage affects the environment, the economy, and the quality of life of the neighbouring areas on land and off shore.

Desalination is receiving increased attention as a means for addressing the water supply challenges of California. The state’s growing population, much of which is located in semi-arid regions, periodic droughts, and other water demands create pressure on existing water supplies and strong incentives to find new ones. (California Desalination Planning Handbook, Dept. of Water Resources, 2008, p.1) With the state’s 3,427 miles of Pacific coastline, (CA Water Plan, 2009, Volume 2, Strategic Resource Management, Chapter 26, Water‐Dependent Recreation. 26‐5) desalination of sea water is a reasonable response to the need for a reliable supply of more potable water—if it can be done without environmental damage.

New desalination technologies exist that produce no brine (and no concentrated brine cocktails). They should be chosen as best available technology (BAT) in the future.

The California report says:

“Consequences of all aspects combined

The brine cocktail damages many life forms – plant and animal; adults, larvae, and eggs. It kills some outright. It prevents reproduction for some. It impedes growth and thriving for some. And the damage can happen at only slightly elevated levels of concentration.

The hypoxic brine and chemical mixture is like plastic wrap suffocating the organisms living on the sea floor. Fish can swim away to better water conditions. Plants, eggs, larvae, and stationery or slow-moving animals like coral, clams, and crabs cannot.

In a comprehensive review of published studies about the impacts of desalination plant discharges, David A Roberts and team reviewed 8 field studies and 10 laboratory experiments that examined a range of salinities and a variety of organisms from waters in the US and Spain. They concluded that experiments in the field and laboratory clearly demonstrate the potential for acute and chronic toxicity, and small-scale alterations to community structure following exposures to environmentally realistic concentrations of desalination brines.

The observed effects of the tests in the study mentioned above included fertilization, germination, growth and development, and mortality on seven organisms. The study was focused on the effects of several brine concentrations and used brine prepared in the laboratory or taken from an RO plant discharge.

It did not look at the effects of the chemical additives or exposure over long terms. Even so, it found effects over limited time periods on several species at some state of development and varying concentrations. For many marine invertebrates the larvae are especially susceptible to brine concentrations.”

Both energy and water are increasing in demand as the population grows and it is critical to choose the right type of technology to sustain such a growth. Wrong choices made due to popularity or quick fixes will lead to long-term consequences.   Desalination with zero liquid discharge should be a mandatory so that large multinational companies will at least spend some funds on R&D towards achieving such a goal. Otherwise it will continue to be a “business as usual”.

 

 

Automobile industry has come a long way since the time of Henry Ford. The internal combustion engine that drives the modern car is slowly but steadily evolving into an emission free engine. The carbon pollution has caused globe to warm and changed the climate and also caused respiratory illness for millions of people around the world for decades. The Carbon pollution was completely ignored in the past while other design features of the car have undergone massive changes. However, when the smog and deteriorating air quality of Delhi and Beijing was beamed around the world in our TV sets, people realized how vulnerable they are to carbon pollution.

But how to eliminate the Carbon emission from our automobiles?

1.The simple answer is to substitute the fossil fuels we use every day such as Petrol and Diesel with Carbon free fuel such as Hydrogen.  Hydrogen being a light gas it has to be compressed and liquefied so that it can occupy less space. However, it requires a special ‘cryogenic tank’ to store liquid Hydrogen at – 253 C. BMW has already produced a commercial vehicle and it is in the market. However, the Hydrogen dispensing stations are limited in numbers. It uses existing internal combustion engine suitably modified for Hydrogen fuel so that they can use existing infrastructure that produces their petrol engines. There is no carbon emission except for water vapour. However, Hydrogen should be generated using renewable energy sources such as solar or wind. Hydrogen generated by reformation of natural gas will still have a Carbon foot print. It can be classified as a Carbon free car depending upon how Hydrogen is generated. However, producing liquid hydrogen or filling in a cryogenic tank is not commercially feasible for individual household. Hydrogen supply will have to be a centralized filling station. BMW has recently focussing their attention towards Fuel cell car. While those early vehicles were fun to drive, they suffered from the inefficiencies of super-cooling the liquefied hydrogen, and the hydrogen vaporizing in storage. Around the turn of the century, BMW began to research the hydrogen-powered, fuel-cell electric vehicle as an alternative to the hydrogen-powered combustion engine.

2.The other alternative is to substitute fossil fuel with compressed Hydrogen that generates an electric power using Fuel cell that drives the motor and the car. Here both fossil fuel and internal combustion engine are substituted with Hydrogen fuel and Fuel cell. This is a marked deviation from a conventional car. Honda of Japan was the first to introduce a commercial car using a Fuel cell. It uses compressed Hydrogen at 70 Mpa pressure that supplies Hydrogen to PEM (proton exchange membrane) Fuel cell that generates power that drives the motor and the car. There is no emission except for water vapour. The car runs smoothly and silently because there is no mechanical engine or moving part. It is truly a Carbon free car if the Hydrogen is generated from a renewable energy source such as solar or wind. It is ideal for houses with roof top solar panels. However, one has to install a water purifier, an electrolyser, a compressor and a compressed tank for Hydrogen storage. If the Hydrogen is generated by steam reforming of Natural gas, then it will have a Carbon footprint and cannot be classified as carbon free car. Generation of Hydrogen using roof top solar panel, electrolysis and compression is possible by individual households but it involves still some risk due to the explosive nature of Hydrogen. A centralized Hydrogen dispensing is still a safer method.  Toyota Mirai Fuel cell car is a new model introduced by Toyota motor Co of Japan. It too has certain additional features such as a power generator for a remote households or camp.

2.The third alternative is to eliminate fuel as well as the engine completely; instead supply power to the motor from a storage battery. Here there is no emission or noise because there is no engine or moving parts similar to Fuel cell car. However, the battery is heavy and occupies a large space and it requires frequent charging from an external power source. The power often comes from the main power grid which carries the power generated from a power station which invariably uses fossil fuel. Though there is no Carbon emission from the electric car it still has Carbon footprint. However, if the power is generated from a renewable energy source such as solar and wind then it can be classified as Carbon free car. It is ideal for houses with roof top solar panels. However, it should be connected to the power grid in parallel. Alternatively, it can be connected to a storage battery if there is no grid.

The Lithium ion battery pack in Tesla Roadster weighs 990 pounds, stores 56 kWh of electric energy, and delivers up to 215 kW of electric power. Tesla battery packs have the highest energy density in the industry. To achieve this energy density, Tesla starts with thousands of best-in-class Lithium-ion cells and assembles them into a liquid-cooled battery pack, wrapped in a strong metal enclosure. The battery is optimized for performance, safety, longevity, and cost. The cells used in a Roadster employ an ideal chemistry for electric vehicles

Nickel Metal Hydride (NiMH) batteries are commonly used in hybrid cars. However, a 56 kWh NiMH battery pack would weigh over twice as much as the Roadster battery. Instead, Tesla uses Li-ion battery cells which dramatically decrease the weight of the Roadster pack and improve acceleration, handling, and range.

With Lithium-ion chemistry, there is no need to drain the battery before recharging – there is no “memory effect”. Roadster owners simply “top-off” each night

Each of the above cars have their own advantages and disadvantages. However, Fuel cell cars have certain advantages over Electric cars in spite of the advancement in battery technology primarily due to the weight of the battery and frequency and time required to charge the battery. Fuel cell car has a capacity to store Hydrogen fuel as well as to generate power onsite and this advantage will go a long way to make fuel cell cars truly carbon free not only for transportation but also for stationery power generation in remote locations.

A large scale deployment of renewable energy generation such as solar and wind around the world can deliver a Car that is truly carbon free. However fossil fuel power generation will continue for years to come as the new technologies are developed to generate power using fossil fuel without emitting Carbon emission such as Carbon recycling. The real winner of the car race will depend upon how a Carbon emission free power generation technology will emerge in the future. Whatever may the power technology Fuel cell be here to stay and if a cheap alternative catalyst is developed for Fuel cell then the race will be well and truly on.(Ref : BMW,Honda,Toyota and Tesla Roadster websites)

 

“The method adopted in Vedanta to impart the knowledge of Brahman is known as the method of superimposition (adhyaaropa) and subsequent negation (apavaada). In the Bhashya, Bhagavatpada says, “The transmigrating self is indeed Brahman. He who knows the self as Brahman which is beyond fear becomes Brahman. This is the purport of the whole Upanishad put in a nutshell. It is to bring out this purport that the ideas of creation, maintenance and dissolution of the universe, as well as the ideas of action, its factors and results were superimposed on the Self. Then, by the negation of the superimposed attributes the true nature of Brahman as free from all attributes has been brought out. This is the method of adhyaaropa and apavaada, superimposition and negation, which is adopted by Vedanta.”  (Ref: What are Upanishads? : An over view by S.N. Sastri on Luthur.com)

The analogy that is often used to describe the process of superimposition and negation is that of ‘using a thorn to remove a thorn’. Finally, when the last thorn is removed, the thorn used to remove it is thrown away as well. Similarly, Carbon can be used to reduce carbon emission while power is generated!

Let us consider the issues of Carbon emission and global warming resulting in climate change in the above context. Recent conference in Climate change held in Paris is acclaimed to be a success to the planet earth collectively adopted by 195 countries both developed and developing. In a nutshell they all have agreed to reduce their carbon emissions to limit the global warming to less than 2C or even 1.5 between 2030 and 2050. Is it really practical to achieve the above target given the nature of reduction and the complexity of imposing such a reduction within the time frame? It is a big question mark.

The only practical method to reduce CO2 is by using Hydrogen CO2 + H2-à CO + H2O and then convert CO into a useful product such as Urea NH2CONH2 a fertilizer. Production of Urea requires additional Hydrogen which is again obtained by combustion of fossil fuel resulting in CO2 emission. Moreover, CO2 will eventually be released at the point of usage of urea later. While trying to reduce Carbon emission one will end up with more Carbon emission in the atmosphere.

The carbon emission from power plants can be substituted with renewable energy sources such as wind and solar at a very high cost but how the emissions from chemical plants such as urea or from automobile emissions, steel plants and cement plants be contained? We should also remember that silicon wafer to produce solar panels consume large amount of power which now comes invariably from fossil fuels. There is a long list of such plants emitting Carbon every day from all over the world.

But there is a possibility to reduce emissions substantially by converting CO2 emissions from power plants into a synthetic fuel which can then substitute fossil fuel to continue power generation. The CO2 resulting from combustion of synthetic fuel will be recycled in the same manner mentioned above thus completing a cycle. To convert CO2 into a synthetic fuel we will require Hydrogen either by renewable sources or non-renewable sources. The non-renewable sources for Hydrogen cannot be a long term solution but renewable Hydrogen is very expensive at this stage. Therefore, Hydrogen is the only source which will not only help reduce Carbon emissions but also help eliminate Carbon completely from planet earth. Renewable Hydrogen is the key to decarbonize the planet earth. However, it may be possible to decarbonize the planet temporarily by using Hydrogen derived from fossil fuel without emitting CO2! It is not just a theory but practical because the technology has already been tested! In this process the Carbon will remain in the loop where it will neither be buried nor emitted into the atmosphere but constantly recycled.

 

 

There is a great deal of misconception about desalination of seawater and the word ‘desalination’ is taken literally as a method of separating  fresh water from seawater but not the separation of salt from seawater. The main focus here is only about recovery of fresh water from seawater or from any saline water sources but not salt. In fact separation of salt from seawater is also known as desalination or desalting. The reason for this misconception is because fresh drinking water is in demand and people are concerned only with fresh water and not the salt. There is a huge demand for fresh drinking water all over the world. Increasing population, large scale usage of fresh water by industries, pollution of fresh water by domestic and industrial effluents, failure of monsoon or seasonal rains due to climate change are some of the factors that contributes to water shortage. There is also a demand for water by agriculture industry both in terms of quality and quantity. Bulk of the ground water is used as a main source of fresh water by agriculture industries in many countries.

But sea water also contains number of minerals or salts which have greater economic and commercial value. In terms of quantity their presence is small, only 3.5% and the rest 96.5% is fresh water. For example Chemical industries such as Caustic soda and Soda ash plants use salt as their raw material. But they also use de-ionized water to dissolve salt to produce brine which is their feed stock.

Therefore Chemical plants are the largest users of seawater in terms of salt as well as fresh water. Power plants mainly located on seashore also use large quantity of de-ionized or desalinated water for boilers and for cooling towers.

Sea is now becoming a great source of fresh water as the inland water supply is becoming scarcer due to dwindling water table by drought or flooding by too much rains, pollution by industries etc. In earlier days seawater was the only source of common salt known as Sodium chloride produced by solar evaporation. Bulk of the salt is till used by this method. Therefore it is logical to locate a chemical plant and a power plant side by side so that seawater can be utilized efficiently.

CEWT (Australian company) has developed a new desalination technology called ‘CAPZ desalination technology’ that can generate fresh water as well as Sodium chloride brine simultaneously which is suitable for Caustic soda/Soda ash production. They can integrate such a facility with a skid mounted Chlorine plant of smaller capacities. This plant can generate large volume of drinking water (WHO standard) as a by-product that can be supplied to municipalities and agriculture industries.

Locating large scale solar salt pans near such a facility will be a problem because it requires a huge area of arid land with good wind velocity and it takes nearly a year to harvest the salt.

Using CAPZ desalination technology one can generate saturated Sodium chloride brine of 315 gpl concentration as well as fresh drinking water directly from seawater. The brine is purified to meet the specifications required by membrane Electrolysis for the production of Caustic Soda. The same brine can also be used for the production of Soda ash using Solvay process.

It is no longer necessary to produce brine from solar salt. Solar salt requires vast area of arid land with good wind velocity and least rain fall and large manual labour force to work under harsh conditions; it is a very slow process and takes almost a year to harvest the salt, which is full of impurities and requires elaborate purification process during the production of Caustic Soda. Such purification process generates huge volume of solid waste for disposal. Chlor-alkali industry is one of the most polluting industries in the world. In fact these impurities can be converted into more value added products such as recovery of Magnesium metal or recovery of Potassium salts. CAPZ technology is developing a ZLD (zero liquid discharge) desalination process where the effluent containing the above impurities such as Calcium, Magnesium and Sulphates are converted into value added products. By recovering more such salts from seawater one can recover additional fresh water. Therefore desalination of sea water is now emerging as an integral part of Chlor-alkali industry. By such integration Chlor-alkali can become a major player is meeting fresh drinking water of a nation.

skid mounted Chlorine plantSkid mounted Cl2 planElectrolysis plant by Thyssen krupBy careful integration and co-location of a desalination plant, Caustic soda plant, Food and pharmaceutical grade salt plant and a power plant  on a sea shore will be a win situation for everybody involved.

Let us take a specific case study of setting up a Caustic soda plant, a captive power plant and a desalination facility.

A typical skid mounted Chlorine plant will have the following configuration:

Capacity of Caustic Soda: 50.7 Mt/day (100% basis)

Capacity of Chlorine        : 45.00 Mt/day (100% basis)

Hydrogen production        : 14,800m3/day (100% basis)

A typical usage of Vacuum salt for such skid mounted Chlorine plant will be about 76.50 Mt/day with a power consumption of 2.29 Mwhr/Mt of NaOH (100%).

A captive power plant of capacity 200Mw will be able to supply necessary power for both Desalination facility as well as Caustic soda plant.

The CAPZ desalination facility can supply a saturated sodium chloride brine (315gpl concentration) 245 Mt/day and 9122 m3/day of fresh drinking water from the desalination plant. This water can be used for boiler feed in the power plant. Surplus water can be supplied as drinking water meeting WHO specifications.

The Hydrogen gas the by-product from caustic soda plant with capacity of 14,800 m3/day can be used to generate clean power using a Fuel cell. The power generated from Fuel cell will be about 20 Mwhr/day that can be supplemented for the Caustic soda production thereby reducing the power consumption from 2.29Mwhr to 1.46 Mwhr/Mt of NaOH (100%)

By careful integration of a large (ZLD) desalination facility with caustic soda plant and power plant it will be possible in future to generate a clean energy using Hydrogen, a by-product of Caustic soda plant and solar thermal plant to produce chemicals in a clean and environmentally sustainable manner.

For further information on CAPZ technology, please contact ahilan@clean-energy-water-tech.com.

 

 

 

Sustainability can be defined as the ability to meet present needs without disturbing Nature’s equilibrium by a holistic approach while not compromising the ability of the future generation to continue to meet their needs. Holistic is “Characterized by the belief that the parts of something are intimately interconnected and explicable only by reference to the whole” (Wikipedia). Mathematically and scientifically any exponential growth or consumption will not be sustainable and such growth will eventually be curtailed by forces of Nature. Unfortunately current models of sustainability do not take a holistic approach but focus only on a continuous growth or expansion to meet the demands of the growing human population thus disturbing the Nature’s equilibrium. The holistic approach is essential because our world is interconnected and any isolated growth or development in one part of the world will affect the other part of the world. Such a growth is counter-productive to human civilization as a whole. At the same time Nature’s equilibrium is critical for the survival of humanity and science should take into account this critical issue while developing solutions to problems. Otherwise such a solution will not be sustainable in the long run.

Nature maintains a perfect equilibrium (dynamic equilibrium) while maintaining reversibility. Both are intricately linked. If the equilibrium is not maintained then it becomes an irreversible process and the entropy of such a system will only increase according to the second law of thermodynamics. The order will become disorder or lead to chaos. Moreover any human interference to nature’s irreversibility and equilibrium by human beings will need energy. Any energy generation process within the system will not be holistic and therefore will not be sustainable.

For example, reverse osmosis (RO) is a major industrial process now used to desalinate sea water/brackish water to potable water. This process is reversing the Nature’s osmotic process by applying a counter pressure over and above the osmotic pressure of the saline water using high pressure pump. This requires energy in the form of electrical energy or thermal energy in the case of distillation. When such energy is generated by burning fossil fuel then the entropy increases because combustion of fossil fuel is an irreversible process. It is clearly not sustainable.

Energy is directly connected with economic growth of the world, but Governments and industries failed to adopt a holistic approach while generating energy by simply focusing only on economic growth. The fossil fuel power generation has resulted in the accumulation of GHG in the atmosphere and in the ocean changing the climate. Power generation by nuclear plant (Fukushima) has spilled radiation into the ocean and has crossed the Pacific Ocean to shores of North America. These are irreversible changes. The human and economic costs from such pollution will easily dwarf the ‘the economic growth’ of the world. It is not holistic because the emissions caused by one country affects the whole world; then it becomes the right of an individual to object to such pollution and it is the obligation of the Governments, United Nations and the industries to protect people from such pollution. Right now all these agencies are helplessly watching the deteriorating situation because they do not have the solution or means to reverse the situation whether it is an advanced country or a poor country; we always measure growth only by income and not by the quality of air we breathe in or water we drink or the environment we live in.

The demand for energy and water are constantly increasing all over the world; and we are trying to meet these demands by expanding existing power plants or by setting up new plants. When we generate power using fossil fuel the heat energy is converted into electrical energy and the products of combustion are let out into the atmosphere in the form of CO2 and Oxides of Nitrogen. It is an irreversible process and we cannot recover back the fossil fuel already burnt. Similarly the electricity generated once used to do some useful work such as lighting or running a motor etc cannot be recovered back.  The process of electricity generation as well as usage of electricity is irreversible. Similarly when it rains the water percolates into the ground dissolving all the minerals, sometimes excessively in some places making it unsuitable to drink or irrigate. This process can be reversed but it again requires energy.

Both the above processes are irreversible and thermodynamically they will increase the entropy of the system. Any energy generation process will have cost implications and therefore irreversibility and entropy are directly linked with economics. Fortunately renewable energy sources offer hope to humanity. Even though the entropy is increased due to its irreversible nature there is no depletion of energy (sun shines everyday). Only Nature can come to human rescue to our sustainability. Science and powerful economies cannot guarantee sustainability irrespective of the size of the budget. There is a myth that billions of dollars can reverse the irreversibility with no consequences.

It raises question on the very basis of science because science depends on “observation and reproducibility” as we know. The biggest question is: “Who is the Observer and what is observed”? When sages of the East such as Ramana Maharishi raises this question, the Science has clearly no answer and the world is blindly and inevitably following the West to the point of no return.

 

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Rise in fossil fuel usageTornadoetsunamisuper bugssealevel riseFish deathFloodingEnvironmental refugeesDraughtbushn firesPresident Obama seized his ‘moment of truth’ when he announced his decision to cut carbon emission by 30% by 2030 in USA. His decision may not be popular in USA and in many parts of the world but it is the right decision. He was able to address to some extent ‘ the inconvenient  truth’ that has nagged him during his second term in office. He  introduced his decision through EPA (Environmental protection authority) effectively bypassing congress. In fact the purpose of creating EPA was to address the environmental issues but it failed in many ways and rest of the world followed such failures time and again. This has resulted in an accumulated carbon both in the atmosphere and in the sea in an unprecedented scale causing disease and environmental degradation world-wide.

Air pollution is costing the world’s most advanced economies plus India and China $3.5 trillion per year in lives lost and ill-health, with a significant amount of the burden stemming from vehicle tailpipes, according to a report by the Organisation for Economic Co-operation and Development (OECD).

In the 34 OECD member states, the monetary impact of death and illness due to outdoor air pollution was $1.7 trillion in 2010. Research suggests that motorized on-road transport accounts for about 50 percent of that cost. In China, the total cost of outdoor air pollution was an estimated $1.4 trillion in 2010. In India, the OECD calculated the toll at $500 billion.

The costs were calculated based on survey data of how much people are willing to pay in order to avoid premature death due to ailments caused by air pollution. The method assigns a cost to the risks of emissions that decision makers can use in weighing public policy decisions.

In addition to the health cost the environmental degradation due to carbon pollution includes global warming resulting in mass extinction of species, causing  mega bush fires that are wiping out forests including rain forests, creating new bugs that are resistant to antibiotics, increasing sea level  that erodes coastal cities and submerge remote islands in pacific displacing millions of people as refugees, acidified oceans with massive extinction of species including fish stock. Such degradation is nothing but suicidal.

When a food or drug is introduced in the market it is subject to scrutiny by FDA (Food and drugs authority), but when it comes to environmental clearance to set up a coal-fired power plant or to set up a seawater desalination plant it is relatively easier to get such clearance from EPA. When  power plants emitted gaseous emissions initially EPA was able to limit the emissions of oxides of nitrogen, sulfur, phosphorous, soot and particulate matter , other organics including mercury and arsenic except carbon dioxide. Carbon dioxide has been accepted as part of the air we breathe in; otherwise no power plant could have been approved because bulk of the emissions are only carbon dioxide. Had EPA acted timely in sixties or even in seventies to curb CO2 emissions an alternative  energy  would have emerged by this time.

Industries and economics were high in the political agenda and the environment was overlooked.  Many drugs were introduced during this period to cure diseases that were actually caused by environmental pollution such as carbon dioxide. Both power industries and drug industries grew side by side without realizing that environment is degraded slowly which causes chronic diseases.

Australia is the largest consumers of power in terms of per capita consumption in the world and yet the new Government in Australia is pushing a bill in the parliament to repel Carbon tax introduced by previous Government. They are also planning to raise revenue up to $ 26 billion for medical research over a time. On one hand politicians want to freely allow unabated carbon emissions into the atmosphere and on the other hand they want to introduce new drugs that can cure diseases  actually caused by  such pollution. It is an anomalous situation created by politics of climate change. Unfortunately carbon pollution has turned into an energy related issue and attracted political attention world-wide. The high cost of cleaning carbon pollution has turned many politicians into skeptics of science on carbon pollution and climate change.

“More than 170 nations have agreed on the need to limit fossil fuel emissions to avoid dangerous human-made climate change, as formalized in the 1992 Framework Convention on Climate Change .However, the stark reality is that global emissions have accelerated (Fig. 1) and new efforts are underway to massively expand fossil fuel extraction by drilling to increasing ocean depths and into the Arctic, squeezing oil from tar sands and tar shale, hydro-fracking to expand extraction of natural gas, developing exploitation of methane hydrates, and mining of coal via mountaintop removal and mechanized long wall mining. The growth rate of fossil fuel emissions increased from 1.5%/year during 1980–2000 to 3%/year in 2000–2012, mainly because of increased coal use.” (Ref : 1)

The coal usage continues to grow especially in Asia due to expanding population and industrial growth and demand for low-cost energy.  USA is expected to achieve energy independence by 2015 which means more fossil fuels are in the pipeline. India and China are planning more coal-fired power plants in the coming decade. Australia is planning for massive expansion of coal and LNG and Coal seam methane gas for exports. Fracturing and hydrocracking of shale deposits are adding to the fuel.

Countries are more concerned with economic growth than the consequences of climate change. Despite recent warning from NASA that the depleting arctic glaciers have reached a ‘point of no return’ and the predicted sea level rise up to 10 feet is irreversible, there is a little reaction from countries across the globe.

There is a clear evidence that shows Green House Gas  emission will continue to increase in the future in spite of growing renewable energy projects because renewable solar panels, wind turbines and batteries will need more power from fossil fuels.  It is critically important to reduce carbon emission with great urgency by substituting fossil energy with renewable energy. For example, concentrated solar power (CSP) can be used instead of large-scale PV solar to reduce carbon footprint.

Solar energy is the origin of all other energy sources on the planet earth and solar energy will be the solution for a clean energy of the future. But how fast solar energy can be deployed commercially in a short span of time is a big issue. The increasing growth of fossil fuel production dwarfs the growth of renewable energy exposing the planet to catastrophic climate change. The GHG emission can be contained only by an aggressive reduction of CO2 emission into the atmosphere as well as by drastic reduction of fossil fuel production. This is possible only by using renewable Hydrogen. The cost of renewable hydrogen is high  but this is the price one has to pay to clean up the carbon pollution before the climate is  changed irreversibly. The obvious method to reduce carbon emissions is to tax carbon in such a way that it will no longer be economically viable to emit carbon to generate power or to transport. Paying carbon tax will be cheaper than paying for diseases and environmental degradation and natural disasters. Clean environment is the key for the survival of our planet and life on earth and one cannot put a price on such a life.

Ref 1:  Citation: Hansen J, Kharecha P, Sato M, Masson-Delmotte V, Ackerman F,et al (2013) Assessing ‘‘Dangerous Climate Change’’: Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature. PLoS ONE 8(12): e81648. doi:10.1371/journal.pone.0081648

 

 

 

Jet fuel from seawatersynthetic  Crude oil -Pilot plantFT recator for syntehtic crudeRecent news from USA has got the attention of many people around the world. “Scientists with the United States Navy say they have successfully developed a way to convert seawater into jet fuel, calling it a potentially revolutionary advancement. Researchers at the Naval Research Laboratory (NRL) developed technology to extract carbon dioxide from seawater while simultaneously producing hydrogen, and then converted the gasses into hydrocarbon liquid fuel. The system could potentially shave hours off the at-sea refueling process and eliminate time spent away from missions.” They estimate the cost of the jet fuel will be anywhere between $3 and $6 per gallon.  It may not be able to compete with traditional petroleum sources due to high energy requirement. However, the main attraction of this process is to extract Carbon dioxide absorbed by the ocean to avoid acidification and to mitigate climate change while making petrol as a Carbon neutral fuel. Ocean has become a rich source of Carbon (Carbon sink) absorbing excess atmospheric Carbon dioxide caused by human beings. Generating Carbon neutral fuel such as SNG (synthetic natural gas), diesel and petrol from air and sea water will be the fastest way to reduce Carbon from the atmosphere. Probably Governments, business and industries will embarrass this concept much quicker than any other mitigating methods simply because it is a revenue generating proposition with a potential to earn carbon credit.

Carbon-neutral fuel is a synthetic fuel (including methanegasolinediesel fueljet fuel or ammonia) that is produced using  carbon dioxide recycled from power plant flue exhaust gas or derived from carbonic acid in seawater  and renewable Hydrogen. Such fuels are potentially carbon-neutral because they do not result in a net increase in atmospheric greenhouse gases.  It is a Carbon capture and recycling (CCR) process.

“To the extent that carbon-neutral fuels displace fossil fuels, or if they are produced from waste carbon or seawater carbonic acid, and their combustion is subject to carbon capture at the flue or exhaust pipe, they result in negative carbon dioxide emission and net carbon dioxide removal from the atmosphere, and thus constitute a form of greenhouse gas remediation. Such power to gas carbon-neutral and carbon-negative fuels can be produced by the electrolysis of water to make hydrogen used in the Sabatier reaction to produce methane which may then be stored to be burned later in power plants as synthetic natural gas, transported by pipeline, truck, or tanker ship, or be used in gas to liquids processes such as the Fischer–Tropsch  (FT) process to make traditional fuels for transportation or heating.

Carbon-neutral fuels are used in Germany and Iceland for distributed storage of renewable energy, minimizing problems of wind and solar intermittency, and enabling transmission of wind, water, and solar power through existing natural gas pipelines. Such renewable fuels could alleviate the costs and dependency issues of imported fossil fuels without requiring either electrification of the vehicle fleet or conversion to hydrogen or other fuels, enabling continued compatible and affordable vehicles.A 250 kilowatt synthetic methane plant has been built in Germany and it is being scaled up to 10 megawatts.” (Wikipedia).

We have been writing about renewable hydrogen (RH) for the past couple of years and often use the phrase, “Water and energy are two sides of the same coin” because we can mitigate climate change using renewable hydrogen (RH) even while the fossil fuel economy can carry on as usual.

By generating Carbon neutral fuels using excess Carbon from air and sea and hydrogen from water (even seawater) using renewable energy sources, the problem of global warming and climate change can be solved because we will not be adding any further Carbon into the atmosphere than what it is today!

Instead of generating solar and wind power and storing them in batteries it will be prudent to generate Carbon neutral fuel from CO2 already available in the system and use them as usual. Meanwhile Hydrogen based power generation and transportation   can be developed as a long term solution.

Fossil-fired power plants produce CO2 (Carbon dioxide) which could be captured and converted to CO (Carbon monoxide) for production of synthetic fuels. CO2 can be converted to CO by the Reverse Water Gas Shift Reaction, CO2 + H2–> CO + H2O. CO could then be used in the F-T reaction with additional hydrogen from water-splitting to produce synthetic fuel such as diesel and petrol as carbon neutral fuels.

 Synthetic fuel by CO2 Capture + H2 from Water-splitting:

Reverse Water Gas Shift                          CO2 + H2 —->  CO + H2O

F-T reaction                                             CO + 2H2 —-> CH2 + H2O

 

Water-splitting                              3H2O + Energy –> 3H2 + 3/2O2

Net reaction                         CO2 + H2O + Energy —>CH2 + 3/2O2

 

In this case, no coal is needed at all, and CO2 is consumed rather than produced. The excess O2 would be used in the fossil power plant that provides the CO2, simplifying CO2 capture. There is currently considerable effort underway on developing CO2 capture systems for new and extant power plants. The increasing concern with Global Climate Change suggests that there is a reasonable likelihood of such plants operating in the timeframe associated with synthetic fuel from carbon dioxide. Such a synergistic system has the potential to significantly reduce our current emissions of CO2 since the carbon in the coal is used once for power production and then again for liquid hydrocarbon fuel synthesis.

Synthetic fuel plant with capacities as low as 1000 barrels/day are commercially feasible using specially designed micro-reactors as shown in the attached photograph (ref: Velocys). Utilizing carbon dioxide from sea and air is the smartest way to mitigate climate change while maintaining fossil fuel based power plants and automobiles without any change or modifications. The same technique can also be applied for biomass gasification plants.

 

salinity of oceansuface salinity changeMeasurement of surface salinityGlobal conveyor beltNASA's aquariusDesalination capacity in GulfFuture desalination capacity-projectedDesalination processBrine characterstics from desal plantsThere is a growing evidence that shows increasing salinity of seawater affects the “water cycle” resulting in climate change. Apart from the natural cycle, the highly saline brine discharged from man-made “desalination” plants around the world also contributes to the increasing salinity of seawater. There are only few desalination plants suppliers world-wide who build such large-scale desalination plants and they use only decades old desalination technologies. They recover 35% of fresh water and discharge 65% highly concentrated, toxic effluent back into the sea. Their main focus of innovation is to cut the energy consumption because it is an energy intensive process. Such energy comes mainly from fossil fuels. The result is unabated Carbon emission, toxic brine discharge into the ocean, warm saline water discharge into the ocean from “once through cooling towers” from co-located power and desalination plants. Currently about 5000 million cubic meters of fresh water is generated  yearly from seawater desalination plants around the world; this capacity is expected to increase to 9000 million cubic meter per year by 2030.The brine outfall from desalination plants will amount to a staggering 30 billion cubic meters/yr. Such a huge volume of saline water with salinity ranging 70,000 ppm up to 95,000 ppm will certainly alter the water chemistry of the ocean. Desalination plant suppliers  are not interested in “innovation” that can recover fresh water without “polluting” the sea. They rather justify using “environmental impact study” which invariably concludes there is absolutely no impact on environment and any toxic discharge into the sea is “harmless”. This practice is going on for decades without any check. Dwindling fish population world–wide is a direct impact of such discharge. Financial institutions such as world bank, Asian development bank etc are willingly finance such projects without questioning such technologies and their impact on marine environment. Their focus is only “return on investment”–the only criteria that is required for funding and not the “cost and benefit analysis”. A detailed analysis will reveal  “handful of rich and powerful” Governments and individuals  can influence the world’s climate  intentionally or unintentionally. The same “rich and powerful” can shun any innovations “that might threaten their business model” and “ nip such innovations or inventions at their bud” because they simply do not believe in Research and Development or unwilling to direct their “cash flow” into R&D because they do not want any  threat for their existing technologies. There are very few financial professionals who can think “outside the box” or predict their financial impact due to innovative technologies of the future. Their financial decisions reflect the sentiments of the financial institutions, namely “the return on investment”.

“When you read about human-induced climate change it’s often about melting glaciers and sea ice, increasing frequency of heat waves and powerful storms. Occasionally you’ll hear about the acidification of the oceans too. What you don’t often hear about is the saltiness of the seas. But according to a new piece of research just published inGeophysical Research Letters that is changing too.The saltiness, or salinity, of the oceans is controlled by how much water is entering the oceans from rivers and rain versus how much is evaporating, known as ‘The Water Cycle’. The more sunshine and heat there is, the more water can evaporate, leaving the salts behind in higher concentrations in some places. Over time, those changes spread out as water moves, changing the salinity profiles of the oceans. Oceanographers from Scripps Institution of Oceanography and Lawrence Livermore National Laboratory fingerprinted salinity changes from 1955 to 2004 from 60 degrees south latitude to 60 degrees north latitude and down to the depth of 700 meters in the Atlantic, Pacific and Indian oceans.

They found salinity changes that matched what they expected from such natural changes as El Niño or volcanic eruptions (the latter can lower evaporation by shading and cooling the atmosphere).

Next the ocean data was compared to 11,000 years of ocean data generated by simulations from 20 of the latest global climate models. When they did that they found that the changes seen in the oceans matched those that would be expected from human forcing of the climate. When they combined temperature changes with the salinity, the human imprint is even clearer, they reported.“These results add to the evidence that human forcing of the climate is already taking place, and already changing the climate in ways that will have a profound impact on people throughout the world in coming decades,” the oceanographers conclude.”

(Ref: Larry O’Hanlon, Discovery News)

Salinity

 

Although everyone knows that seawater is salty, few know that even small variations in ocean surface salinity (i.e., concentration of dissolved salts) can have dramatic effects on the water cycle and ocean circulation. Throughout Earth’s history, certain processes have served to make the ocean salty. The weathering of rocks delivers minerals, including salt, into the ocean. Evaporation of ocean water and formation of sea ice both increase the salinity of the ocean. However these “salinity raising” factors are continually counterbalanced by processes that decrease salinity such as the continuous input of fresh water from rivers, precipitation of rain and snow, and melting of ice.

 

Salinity & The Water Cycle 

Understanding why the sea is salty begins with knowing how water cycles among the ocean’s physical states: liquid, vapor, and ice. As a liquid, water dissolves rocks and sediments and reacts with emissions from volcanoes and hydrothermal vents. This creates a complex solution of mineral salts in our ocean basins. Conversely, in other states such as vapor and ice, water and salt are incompatible: water vapor and ice are essentially salt free.

Since 86% of global evaporation and 78% of global precipitation occur over the ocean, ocean surface salinity is the key variable for understanding how fresh water input and output affects ocean dynamics. By tracking ocean surface salinity we can directly monitor variations in the water cycle: land runoff, sea ice freezing and melting, and evaporation and precipitation over the oceans. 

Salinity, Ocean Circulation & Climate

Surface winds drive currents in the upper ocean. Deep below the surface, however, ocean circulation is primarily driven by changes in seawater density, which is determined by salinity and temperature. In some regions such as the North Atlantic near Greenland, cooled high-salinity surface waters can become dense enough to sink to great depths. The ‘Global Conveyor Belt’ visualization (below) shows a simplified model of how this type of circulation would work as an interconnected system.
The ocean stores more heat in the uppermost three (3) meters than the entire atmosphere. Thus density-controlled circulation is key to transporting heat in the ocean and maintaining Earth’s climate. Excess heat associated with the increase in global temperature during the last century is being absorbed and moved by the ocean. In addition, studies suggest that seawater is becoming fresher in high latitudes and tropical areas dominated by rain, while in sub-tropical high evaporation regions, waters are getting saltier. Such changes in the water cycle could significantly impact not only ocean circulation but also the climate in which we live.

(Ref: NASA earth science)

The four main forces that control the earth’s climate are “Sea, Sun, Moon and earth’s rotation”  and  interference by human beings will alter the equilibrium of the system. In order to keep up its equilibrium, Nature is forced to change the climate unpredictably with devastating effects. We cannot underestimate the pollution caused by human beings because they are capable of altering the Nature’s equilibrium over a period no matter how “miniscule” (parts per millions or billions) the pollution may be. Any future investment on large-scale infrastructures should take into account the “human induced climate change” in their model and projections, failing which “climate change” will prove them wrong and the consequences will be dire.

Reference :  Environmental Impacts of Seawater Desalination: Arabian Gulf Case Study

Mohamed A. Dawoud1 and Mohamed M. Al Mulla

1 Water Resources Department, Environment Agency, Abu Dhabi, United Arab

Emirates

2Ministry of Environment and Water, Dubai, United Arab Emirates

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