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Tag Archives: Electrolysis

Photovoltaic  solar energy  is becoming popular as a source of clean energy and an alternative to fossil fuels to combat climate change. Though the initial cost is expensive people have started realizing the potential of PV solar as  a real alternative to grid power, especially when they can export surplus power to the grid and earn some revenue. It is  a source of income for potential investors as the energy cost keeps rising steadily. The cost of solar panels, batteries and inverters are slowly coming down as the systems get more popular and more competition is created in the market. However, during cloudy days or when the solar hours are less, the power generation by solar panels is considerably low. Moreover, the ‘power in tariff ‘ system is not available in many countries especially in developing countries. Therefore, energy storage becomes an issue. Lead acid batteries serve as storage devices for smaller applications but it becomes expensive for lager systems. Operation and maintenance, replacement and waste disposal are some of the issues with battery storage.

Generating Hydrogen on site using solar power and storing Hydrogen under pressure in a tank is the best method of storing solar energy. The stored Hydrogen can be used to generate power using a Fuel cell as and when we need power. However, the amount of energy required to convert water into Hydrogen using Alkaline Electrolyzer or Solid Polymer Electrolyzer is still high, averaging 5-7 kwhrs/m3.When you calculate the economics of  Hydrogen storage versus battery storage using a computer modeling for a stand alone system, it is clear that Hydrogen storage is more economical and also guarantees an uninterrupted power supply using a Fuel cell.

One US company has developed a Carbon doped Titanium oxide nanopowder visible light photo catalyst to  generates Hydrogen using sun’s light energy. The company claims that it consumes only one-third of the power consumed by PEM Electrolyzer or half of an Alkaline Electrolyzer.It can be easily installed at roof tops and it can generate Hydrogen even at one-third of sunlight because it can effectively use short UV light and blue wave length of suns light because these energetic wavelengths penetrate cloud cover more effectively than the rest of sunlight. A 2mm modular solar panel can be installed on roof top or installed in multi-acre field installations. Even during the absence of sunlight the company claims it can use grid power to generate Hydrogen using its hybrid integral (MMO) Mixed metal oxide Titanium anode as efficiently as PEM Electrolyzer.

While a PEM electrolyzer generates about 1.3kg Hydrogen from a power input of 100Kwhrs, this model can generate about 2.5kg Hydrogen using MMO + TiO2 anode and about 3.8kg using TiO2 alone. (Based on higher heating value of Hydrogen at 39.4 kwhrs/kg).The panel consuming 26.7kwhr power at 1.0Volt DC current at Anode can generate 1.25kg Hydrogen with Electrolysis electrical efficiency at 148%.  This will make Hydrogen fuel a commercial reality because it will consume only 21.36 kwhrs of Dc power to generate 1 Kg Hydrogen. The generated Hydrogen can generate about 15 Kw power using a Fuel cell. This is an elegant solution to generate and store power using sun’s light than Photovoltaic power.

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Renewable energy industry has slowly but steadily started expanding in many parts of the world in spite of  high cost of investment and high  cost of energy. Countries like US, Germany and China are now investing on large-scale solar and wind technologies, opening new avenues for investments and employment opportunities. Many of these technologies will undergo several changes over a time before it can completely substitute fossil fuels. How long this process will take will depend upon number of factors; but the single biggest driving force will be ‘the issue global warming and its consequences” and also on uncertainties over oil reserves in the world. Nothing dramatic will happen in the near future except that the concept of alternative source of energy will expand rapidly. It is also an opportunity to discover new forms of fuels, power generation and distribution methods.

The concept of solar energy is now well-recognized as an alternative source of energy because, it is abundantly available, it is clean, generates no pollution and it is silent. The major raw materials such as Silica  and Gallium Arsenide  are  also available but some of the rare earth materials used in PV industries and batteries  are available only in certain parts of the world.  China is endowed with many such rare earth resources. For example, Lithium has limited resources and now bulk of it is produced from natural brines similar to the one at Atacama deserts in South America. It is also available in the form of minerals and ores which many countries are now trying to exploit commercially.

The storage of energy from  solar and wind is  done using deep cycle batteries, most of which are Lead-acid batteries. Bulk of the used Lead acid batteries are recycled but the demand for such batteries keeps increasing. As I mentioned in my previous articles, the sheer weight of these batteries, space required to install them, capacity use, capacity constraints, regular need for  maintenance and life cycle are some of the issues that are critical for renewable industries. In deep cycle batteries, discharging stored energy below certain levels dramatically reduces the life span. Hot climate conditions have certain impacts on maintaining such batteries.Life of a battery is critical because when you calculate the cost of energy over the life cycle of 25 years,the several replacements of battaries and their cost will have a dramatic effect on the cost of energy.

Batteries are indispensable tools in energy industries but their usage can be minimized  to a great extent by using Hydrogen as a storage medium. Let us analyze a simple example of a PV solar system for power generation. We made a computer simulation on three  different  scenario for a PV solar system for a small residence with power consumption at 15,500kwhrs/day. First simulation was based on PV solar, direct grid connect, without  storage batteries but connected directly to the grid, assuming the grid power tariff  is at $0.10/kwhrs and sale to grid tariff at $ 0.30/kwhrs.The second simulation was based on grid independent system  using battery  storage for 8 hrs autonomy. The third simulation is also grid independent, but solar power is connected to an Electrolyzer to generate Hydrogen and store it in a tank. We used a small capacity battery, less than twenty percent  of the capacity used in the earlier case and a Hydrogen storage with Fuel cell along with an inverter. The stored Hydrogen was used to generate power to meet the requirement of the residence, instead of supplying power directly from the battery. The cost of energy using direct grid connect was the lowest $$0.33/kwhrs, while Grid independent with battery storage ,the cost of power was $1,20/kwhrs.In third  scenario with Hydrogen and Fuel cell the cost of power was $ 1.90/kwhrs, but there was surplus Hydrogen in the storage tank. With Hydrogen as a storage medium, the cost of power is high due to initial investment but it is maintenance free and ideal for remote locations.

The Hydrogen and Fuel cell solution though expensive, has a several advantages. The power generated by PV solar is stored in the form of Hydrogen instead of storing in batteries. A single battery is used to keep up a steady current to Electrolyzer but bulk of the energy is stored in the form of Hydrogen. Another advantage with this system is that stored Hydrogen can also be used as a fuel for residential heating as well as to fuel your car.

It is amazing that highly combustible Hydrogen is a constituent of cool water. As long as it remains a part of a water molecule we are able to handle it easily. Water is always in a state of ionization with H+ and OH- ions in a dynamic equilibrium. The electrical conductivity of pure water which is completely free from any other ions is almost zero. In a solid polymer electrolyzer, which is the reverse of Fuel cell, water is decomposed into Hydrogen and Oxygen while passing a Direct current. Electrolyzer is an electrolytic cell similar to battery, containing an Anode, Cathode and Electrolyte. In a solid polymer Electrolyzer, the electrolyte is a polymer membrane. Water is decomposed as shown in the following reaction:

At Anode of electrolyzer:               H2O——– 0.5 O2 + 2e + 2H†

At Cathode of electrolyzer:             2H† + 2e —— H2

The purity of water is critical in the above process of electrolysis. In conventional electrolysis, water with addition of potash lye (KOH) acts as an electrolyte. But in the above process there is no need for any addition of lye. Moreover, Hydrogen can be generated at high pressure so that further compression becomes easier. In cases of power generation using Fuel cell, the Hydrogen pressure from Electrolyzer is sufficiently high, obviating the usage of an additional compressor.

The electrical conductivity of water increases as the concentration of dissolved salts increases. That is why the electrical conductivity of seawater is much higher than your tapwater.But this salt can be removed by the process of desalination using ‘reverse osmosis’ systems.

When you separate pure water and salt water using a semi permeable membrane there is natural tendency for pure water to pass across the membrane to pure water side. This process is called ‘Osmosis’. The process continues till the concentration of water on both side of the membrane becomes equal. Nature does not like disparities between strong and weak and always tend to make both equal. By reversing this principle of osmosis, we can separate salt water into pure water and highly concentrated salt water known as brine. This process is called ‘Reverse osmosis’. We will discuss about this process later.

If your tap water is not very hard, say such as, total dissolved solids TDS is around  500ppm (Part per million), then the osmotic pressure is not high, which means you do not need to use a high pressure pump. Higher the TDS level, higher the osmotic pressure and higher the power consumption will be. You can install a reverse osmosis system based on your water analysis. You have to use a pure water with low conductivity 10-15 micro Siemens/cm.The reverse osmosis system can be connected to your tap and  store pure water while draining the salt water into the drain. You can use this pure water to an Electrolyzer to generate Hydrogen. The Hydrogen can be stored in a tank made up of Carbon composite materials that can withstand high pressure and approved by regulatory authorities.

This article is only to understand how Hydrogen can be generated using your tap water. The actual implementation of the system requires knowledge and experience in installing such a system. But we will release an eBook, a step by step guide to set up your power generation system as well fuelling your Fuel cell car, using Hydrogen. An independent power generation and fuelling system using only solar power and water will soon become a commercial reality because, it is a clean and sustainable solution for all our energy problems. The PV solar industries are already expanding at a faster rate and solar Hydrogen will soon become a final solution.

In a Regenerative fuel cell the results of redox reaction between Hydrogen and Oxygen, are power and water; the above reaction can be reversed in the same electrochemical process to regenerate hydrogen and oxygen. Such a system is called ‘regenerative fuel cell’. It is a perfect example of a closed circuit system. In ancient Hindu mythology there were citations that claim water came from fire and fire came from water. Two gaseous elements Hydrogen and oxygen reacts violently rather explosively resulting in cool water. Perhaps Hindu mythology terms this reaction as fire which results in water. Similarly by passing a direct current into water, it splits water into oxygen and regenerates Hydrogen, which is a symbolic representation of Fire. Many would have watched a number of ‘you tube videos footings’ on water gas. The water gas or Brown’s gas is a mixture of Hydrogen and oxygen along with un-dissociated water molecules liberated during the process of electrolysis. It can be lit into a flame similar to Oxy-acetylene flame and can be used even to cut metal plates. That is the power of brown’s gas, which I call Oxy-Hydrogen gas. This torch is commercially marketed for metal cuttings applications. But production of pure Hydrogen completely free from Oxygen is a matter of great commercial importance.

Hydrogen is one of the lightest gases and it has a strong bondage with noble metals like Platinum and Palladium. Platinum  catalyst with carbon as a carrier has a wider industrial applications such as hydrogenation in fine chemicals and pharmaceuticals. The author has experience in such applications in bulk drug manufacturing such as Ephedrine and Paracetamol. In a PEM (Proton exchange membrane fuel cell) MEA (membrane electrode assembly) is the heart. The Platinum catalyst coated on the surface of the ‘Nafion’ membrane reacts with gaseous Hydrogen gas. It strips the electron from hydrogen atom while the polymer membrane allows only proton to pass through. The expelled electron flows around the circuit. Flow of electron is nothing but current or electricity. The proton crosses the membrane and reacts with incoming Oxygen through cathode forming water. It is an exothermic reaction and generates heat similar to any combustion reaction, that has to be dissipated.In larger installation we can use this waste heat for a typical CHP (combined heat and power applications) such as power and steam or chilled water or for space cooling. Fuel cell (based on Hydrogen fuel) operates quietly with absolutely no emission except water, and of course, there is no smoke. It is an ideal power source for 24×7 applications such as hospitals, call centers, departmental stores and continues process industries.

In the reverse process of a Fuel cell, the electrochemical device becomes an Electrolyzer splitting water into Hydrogen and oxygen. The electrolyzer works the same way as Fuel cell except in reverse direction; feed is de-ionized water and the products are Hydrogen and Oxygen. In bipolar alkaline electrolyzer, a catalyst such as potash lye is added where in solid polymer electrolyzers platinum acts as a catalyst like a Fuelcell. The generated Hydrogen comes under pressure obviating the use of an extra compressor. The Hydrogen is stored in cylinders for further usage.

As I mentioned in my previous articles the power required to split water into Hydrogen and Oxygen is more than the power generated from the resulting Hydrogen by a Fuelcell.That means an input of excess energy is necessary for a regenerative fuel cell to run successfully .Where this energy will come from depends on the cost benefit analysis to be made. Surplus Hydro power is ideal for such regenerative fuel cell applications. But we can also use various other renewable energy sources such as wind, solar, geothermal, OTEC depending upon the site and applications. The biggest advantage with regenerative fuel cell is there is no other input except the excess power to be supplied. When renewable energy is deployed on large commercial scales then regenerative fuel cell will become a clean solution of the future. I have no doubt in my mind that this will become a commercial reality. Of course the top policy makers should understand the potential and make a right decision and encourage more business and industries to deploy such systems. The energy costing model cannot be based on fossil fuel model because fossil fuel is not renewable. This is the crux of the problem.

In our future articles we will present case studies of various clean energy systems that are already in commercial operation. I also welcome articles from clean energy professionals with life project experience and problems they face. I welcome comments and feedback from business, industries and people.

Hydrogen is the cleanest source of energy that can power your homes and fuel your cars. It can potentially substitute diesel and petrol or coal and clean up our environment. Hydrogen has been manufactured industrially for the past several decades and transported across thousand of kilometers by pipelines in Europe. The science and technology of Hydrogen is well known but its application to generate power and fuel a car is relatively new. The gasoline internal combustion engines that drive our gasoline cars can be modified to suit Hydrogen fuel. But the physical and chemical properties of Hydrogen gas created a necessity to alter existing gasoline engines for commercialization. But such conversion has been painfully slow for couple of reasons. There is a stiff resistance from gasoline cars to switch over to Hydrogen because they have a well established infrastructure to manufacture gasoline cars and to supply gasoline through well established distribution network. But Hydrogen cars lack both of them. Even if the cars can be modified for Hydrogen, there are no sales or distribution network for the fuel Hydrogen, similar to Gasoline. Even consumers need to be educated that Hydrogen is safe, environmentally friendly and we need not depend on import of oil and so on. It is a blessing in disguise that Hydrogen can be generated by each home, business and industries for their captive use from their tap water. Recently Hydrogen fuelled scooters have been introduced in the market. There are number of advertisements in the media too; that you can fit a Hydrogen generator at your car that will reduce your gasoline bills substantially and also cut your emissions.But these Electrolyzers can generate only water gas and not a pure Hydrogen. Yet such simple devices can help reduce your petrol bills to an extend .If things are so simple why are we still struggling with high crude oil prices and increasing electricity bills? Let us examine this in detail. Water (H2O) can be split into Hydrogen (H2) and Oxygen (O2) by simply passing an electric current through water using a battery. The water disassociate as follows: 2    H2o———   2 H2+ )2 Stochiometrically, it means 36 lits of water will generate 4 Kgs of Hydrogen and 32 kgs of Oygygen.The current PEM (Proton exchange membrane) Fuel cell car (Honda FCX clarity) can drive 100 miles with just 0.105 kgs of Hydrogen from 5000 psi Hydrogen tank. Similarly 4kgs of hydrogen can generate about 100 kws of electricity using PEM Fuel cell, based on a conservative estimate; but 4Kgs of gasoline can generate only 15 kW electricity. The gasoline engine offers only 100km mileage from 13 kgs (16lits) of gasoline. In other words, 0.105 kgs of Hydrogen at 5000 psi gives the same mileage as 16 lits of Gasoline.  This is the amazing power of water, yet to be unleashed! The tap water is suitable to generate Hydrogen by adding a little amount of potash lye to improve the electrical conductivity. An Alkaline water electrolyzer can be attached to the water tank to generate required amount of Hydrogen based on the above calculation. The resulting Hydrogen has to be compressed to a required level. The power consumption to electrolyze water will be about 75-80 kwhrs per Kg of Hydrogen generated at 5000 psi.Therefore 4Kgs of Hydrogen will need a power of 300kwhrs costing about $30 for a total mileage of 3800 miles. You will need a small reverse osmosis unit to be attached to your water tap so that the water is de-ionized so that there is no precipitation in the Electrolyzer or reduction in the efficiency of electrolysis. Recently, Suzuki Bargeman introduced Hydrogen Fuel cell scooter which claims to offer a mileage of 200km from 12 lits Hydrogen (carbon composite material) tank at an higher pressure of 10,000psi.The future of Hydrogen car is very promising and finally the world can hope to get rid of smoke and noise from our roads and cities.

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