Skip navigation

Tag Archives: Energy

Generating electricity using fossil fuel is a well-established technology, that has been practiced over several decades all over the world, despite its low efficiency. But this technology inherited certain disadvantages even before it was commercialized such as post combustion emissions, large amount of waste heat, and water intensity. Millions of people died of Carbon pollution over decades. Large scale usage of water both inland and on shore power stations created shortage of drinking water in many parts of the world resulting in desalination technologies creating its own environmental issues. Large scale mining of coal and unsustainable exploitation of oil and gas both on shore and off shore caused enormous environmental pollution. However, such emissions were completely ignored while the world celebrated the discovery of electro-magnetism, steam engine and petrochemicals. Millions of people were employed, and industries grew worldwide. Energy became synonymous with security of a nation. Population grew exponentially. However, we have reached a point in the history of mankind and all great discoveries once acclaimed as human achievements have started a new painful chapter of warming globe and changing climate for new generations to deal with. It is a great challenge of our time, but new generation can take this challenge and convert them into opportunities. The past lessons can show them a new clean and sustainable pathway while dealing with ever increasing population growth.

The challenge for the new generation is to curtail and eliminate Carbon pollution completely while meeting the energy demand in a time bound manner because we are running out of time. Currently renewable energy generation is too low to meet these challenges within the time frame to avert disastrous consequences scientists predict. Renewable Hydrogen is a potential substitute for fossil fuel to eliminate Carbon pollution but that will not solve our current problem soon because renewable energy generation is too small and too slow while our energy demand is huge. Battery technology is only a storage technology and without a base load power generation all other forms of technologies will not meet our current challenges. I am not discounting the potential of renewable energy and its critical role in the future energy mix but that alone will not solve the current crisis. Hydrogen is a weak and unstable atom and it requires a backbone such as Carbon. That is why Hydrogen do not exist in a free state in Nature, but it exists in the form of water or natural gas. Therefore, it is only logical to convert renewable hydrogen into renewable natural gas so that it can be used as a fuel as we have been using for decades. It does not require to create a special type of infrastructure such as required for Hydrogen or any storage technologies.

Our focus should be to achieve Zero Carbon emission in the shortest time scale possible while generating a base load power of 24 x7 using a renewable energy source. It looks like a daunting task but, it is not too big a challenge to overcome. In fact, the technologies are already available, and we are almost there to achieve the above, but governments should understand the challenge and its gravity and extend all the support it requires. Government around the world should implement the following with great urgency to achieve the above objectives.

1.Tax Carbon with immediate effect and minimum tax should be $500/ Mt of CO2 emitted. It should be centrally monitored by government agencies with appropriate technology implementations.

  1. Encourage Oxy combustion technologies for coal, oil and gas-based power plants with incentives to eliminate emissions pollution and reduce the cost of Carbon capture.
  2. Encourage large scale deployment of super critical Carbon dioxide power generation technologies with liberal grants and low interest loans for research and development of super critical CO2 technologies using Brayton cycle using fossil fuels with Zero Carbon emission.

4.Encourage large scale deployment of SNG plants using CO2 and renewable Hydrogen.

By using the above steps all fossil fuel-based power plants existing and operating can be converted and continue to generate base load power 24 x7 with Zero Carbon Emission within a time frame. Simultaneously it will generate large scale renewable hydrogen and renewable synthetic natural gas which can generate base load power with Zero Carbon emission. Such Zero emission power plants can then power all electric and fuel cell cars and eliminate Carbon pollution completely from our roads. The above implementation will create millions of jobs worldwide!

The greatest advantage of these technologies is to recycle Carbon indefinitely while generating power using renewable natural gas with Zero Carbon emission and fresh fossil fuel usage will be gradually eliminated from our planet earth.

 

Advertisements

solar absorption chillersAir conditioning makes up bulk of the power usage, especially in tropical countries where the sun is shining almost throughout the year and the humidity levels are high. It makes a perfect sense to use solar heat to cool homes, business and factories. Many air-conditioning systems are commercially available using simple roof top PV solar panels to generate electric power to run an electric window air-conditioners. This system uses commercially available solar panels and window air-conditioners and uses solar power to generate electricity to run the compressor and the blower in the air-con unit. This system requires large storage battery to store adequate electricity to run your air-conditioners for specified period. Otherwise it requires a large area of solar panels to meet the demand. The efficiency of such systems can be improved using DC operated compressors and fans. However, renewable energy such as solar is still expensive to run air-conditioners because of high initial investment cost, though it may be economical in the long run as the cost of solar panels and accessories slowly come down over a time. Moreover such systems are limited to small air condition capacities.

solar chillers-typical apacitiessolar absorption chillerFor large air-conditioning requirements such as business and factories, we need a system that uses solar heat directly to air-condition the premises with higher efficiency and thermal storage capabilities. Designing such a system is not very difficult because most of the components necessary to install such systems are readily available. One can install an air-conditioning system based on 100% solar thermal heat with molten salt thermal storage. Alternatively, a hybrid system can be installed based on solar heat without a thermal storage but using   city gas supply. Many countries use gas for heating during winter seasons but do not use gas during summer. These countries can use a hybrid (solar-gas) system to air-condition their premises and avoid peak electric usage during summer seasons thereby avoiding electrical black-outs. The advantage with such system is they can also be used for heating the premises during winter season. With changing climate due to global warming many warm countries like India also experiences cold temperatures during winter season. For example New Delhi in India has experienced a sharp drop in temperature up to 15-20c during winter from earlier winters.

Solar cooling systems to date have used waste heat gas absorption chiller heaters, which utilize the waste heat from cogeneration systems (CGS) for the cold water. However, these chiller heaters with their established technologies are devices designed for the effective use stable CGS high-temperature waste heat, so they cannot accommodate the preferential use of solar heat when solar hot water temperatures suddenly change from large variations in the heat collector temperatures due to changes in the weather. The new solar absorption chiller heaters are now specially designed for the effective use of low-temperature solar heat to address this problem and improve the energy conservation effect from solar cooling system. Hot water at less than 90C can be used for such systems and typical chillers with their rated specification are shown in the figures.solar trough

The efficiency of the system can be vastly improved by using parabolic solar concentrators, up to 27 times higher than ordinary flat plate solar collectors resulting in conversion efficiency up to 85% in heating and cooling. By selecting a natural refrigerant such as R717 we can save the environment from ozone depletion. Such systems offer flexibility to use exhaust heat, natural gas along with solar thermal storage up to 220C (phase transition temperature).The system offers an attractive return on investment, electricity savings and Carbon pollution reduction. The system can be designed from 5TR up to 200TR refrigeration capacity for 100% solar and up to 1000TR for a solar-gas hybrid systems. The solar thermal system with molten salt storage is versatile in its application because the same system can be designed for heating or cooling or on-site power generation for continuous applications.

.

The recent debate between the presidential nominees in US election has revealed their respective positions on their policies for an energy independent America. Each of them have articulated how they will increase the oil and gas production to make America energy independent, which will  also incidentally create number of jobs in an ailing economy. Each one of them will be spending a billion dollar first, in driving their messages to the voting public. Once elected, they will explore oil and gas aggressively that will make America energy independent. They will also explore solar and wind energy potentials simultaneously to bridge any shortfall. Their policies   seem to be unconcerned with global warming and its impact due to emission of GHG but, rather aggressive in making America an energy independent by generating an unabated emission of GHG in the future. Does it mean an ‘energy independent America’ will spell a doom to the world including US?

The best option for America to become energy independent will be to focus  on energy efficiency of existing technologies and systems, combining renewable fossil fuel energy mix, base load renewable  power and storage technologies, substituting Gasoline with Hydrogen using renewable energy sources. The future investment should be based on sustainable renewable energy sources than fossil fuel. But current financial and unemployment situation in US will force the new president to increase the conventional and unconventional oil and gas production than renewable energy production, which will be initially expensive with long pay pack periods but will eventually meet the energy need in a sustainable way. The net result of their current policies will be an enhanced emission of GHG and acceleration of global warming. But the energy projections in the U.S. Energy Information Administration’s (EIA’s) Annual Energy Outlook 2012 (AEO2012) projects a reduced GHG emission.

According to Annual Energy Outlook 2012 report:

“The projections in the U.S. Energy Information Administration’s (EIA’s) Annual Energy Outlook 2012 (AEO2012) focus on the factors that shape the U.S. energy system over the long-term. Under the assumption that current laws and regulations remain unchanged throughout the projections, the AEO2012 Reference case provides the basis for examination and discussion of energy production, consumption, technology, and market trends and the direction they may take in the future. It also serves as a starting point for analysis of potential changes in energy policies. But AEO2012 is not limited to the Reference case. It also includes 29 alternative cases, which explore important areas of uncertainty for markets, technologies, and policies in the U.S. energy economy. Many of the implications of the alternative cases are discussed in the “Issues in focus” section of this report.

Key results highlighted in AEO2012 include continued modest growth in demand for energy over the next 25 years and increased domestic crude oil and natural gas production, largely driven by rising production from tight oil and shale resources. As a result, U.S. reliance on imported oil is reduced; domestic production of natural gas exceeds consumption, allowing for net exports; a growing share of U.S. electric power generation is met with natural gas and renewable; and energy-related carbon dioxide emissions stay below their 2005 level from 2010 to 2035, even in the absence of new Federal policies designed to mitigate greenhouse gas (GHG) emissions.

The rate of growth in energy use slows over the projection period, reflecting moderate population growth, an extended economic recovery, and increasing energy efficiency in end-use applications.

 

Overall U.S. energy consumption grows at an average annual rate of 0.3 percent from 2010 through 2035 in the AEO2012 Reference case. The U.S. does not return to the levels of energy demand growth experienced in the 20 years before the 2008- 2009 recession, because of more moderate projected economic growth and population growth, coupled with increasing levels of energy efficiency. For some end uses, current Federal and State energy requirements and incentives play a continuing role in requiring more efficient technologies. Projected energy demand for transportation grows at an annual rate of 0.1 percent from 2010 through 2035 in the Reference case, and electricity demand grows by 0.7 percent per year, primarily as a result of rising energy consumption in the buildings sector. Energy consumption per capita declines by an average of 0.6 percent per year from 2010 to 2035 (Figure 1). The energy intensity of the U.S. economy, measured as primary energy use in British thermal units (Btu) per dollar of gross domestic product (GDP) in 2005 dollars, declines by an average of 2.1 percent per year from 2010 to 2035. New Federal and State policies could lead to further reductions in energy consumption. The potential impact of technology change and the proposed vehicle fuel efficiency standards on energy consumption are discussed in “Issues in focus.”

Domestic crude oil production increases

Domestic crude oil production has increased over the past few years, reversing a decline that began in 1986. U.S. crude oil production increased from 5.0 million barrels per day in 2008 to 5.5 million barrels per day in 2010. Over the next 10 years, continued development of tight oil, in combination with the ongoing development of offshore resources in the Gulf of Mexico, pushes domestic crude oil production higher. Because the technology advances that have provided for recent increases in supply are still in the early stages of development, future U.S. crude oil production could vary significantly, depending on the outcomes of key uncertainties related to well placement and recovery rates. Those uncertainties are highlighted in this Annual Energy Outlook’s “Issues in focus” section, which includes an article examining impacts of uncertainty about current estimates of the crude oil and natural gas resources. The AEO2012 projections considering variations in these variables show total U.S. crude oil production in 2035 ranging from 5.5 million barrels per day to 7.8 million barrels per day, and projections for U.S. tight oil production from eight selected plays in 2035 ranging from 0.7 million barrels per day to 2.8 million barrels per day (Figure 2).

With modest economic growth, increased efficiency, growing domestic production, and continued adoption of nonpetroleum liquids, net imports of petroleum and other liquids make up a smaller share of total U.S. energy consumption

U.S. dependence on imported petroleum and other liquids declines in the AEO2012 Reference case, primarily as a result of rising energy prices; growth in domestic crude oil production to more than 1 million barrels per day above 2010 levels in 2020; an increase of 1.2 million barrels per day crude oil equivalent from 2010 to 2035 in the use of biofuels, much of which is produced domestically; and slower growth of energy consumption in the transportation sector as a result of existing corporate average fuel economy standards. Proposed fuel economy standards covering vehicle model years (MY) 2017 through 2025 that are not included in the Reference case would further cut projected need for liquid imports.

Although U.S. consumption of petroleum and other liquid fuels continues to grow through 2035 in the Reference case, the reliance on imports of petroleum and other liquids as a share of total consumption decline. Total U.S. consumption of petroleum and other liquids, including both fossil fuels and biofuels, rises from 19.2 million barrels per day in 2010 to 19.9 million barrels per day in 2035 in the Reference case. The net import share of domestic consumption, which reached 60 percent in 2005 and 2006 before falling to 49 percent in 2010, continues falling in the Reference case to 36 percent in 2035 (Figure 3). Proposed light-duty vehicles (LDV) fuel economy standards covering vehicle MY 2017 through 2025, which are not included in the Reference case, could further reduce demand for petroleum and other liquids and the need for imports, and increased supplies from U.S. tight oil deposits could also significantly decrease the need for imports, as discussed in more detail in “Issues in focus.”

Natural gas production increases throughout the projection period, allowing the United States to transition from a net importer to a net exporter of natural gas

Much of the growth in natural gas production in the AEO2012 Reference case results from the application of recent technological advances and continued drilling in shale plays with high concentrations of natural gas liquids and crude oil, which have a higher value than dry natural gas in energy equivalent terms. Shale gas production increases in the Reference case from 5.0 trillion cubic feet per year in 2010 (23 percent of total U.S. dry gas production) to 13.6 trillion cubic feet per year in 2035 (49 percent of total U.S. dry gas production). As with tight oil, when looking forward to 2035, there are unresolved uncertainties surrounding the technological advances that have made shale gas production a reality. The potential impact of those uncertainties results in a range of outcomes for U.S. shale gas production from 9.7 to 20.5 trillion cubic feet per year when looking forward to 2035.

As a result of the projected growth in production, U.S. natural gas production exceeds consumption early in the next decade in the Reference case (Figure 4). The outlook reflects increased use of liquefied natural gas in markets outside North America, strong growth in domestic natural gas production, reduced pipeline imports and increased pipeline exports, and relatively low natural gas prices in the United States.

Power generation from renewable and natural gas continues to increase

In the Reference case, the natural gas share of electric power generation increases from 24 percent in 2010 to 28 percent in 2035, while the renewable share grows from 10 percent to 15 percent. In contrast, the share of generation from coal-fired power plants declines. The historical reliance on coal-fired power plants in the U.S. electric power sector has begun to wane in recent years.

Over the next 25 years, the share of electricity generation from coal falls to 38 percent, well below the 48-percent share seen as recently as 2008, due to slow growth in electricity demand, increased competition from natural gas and renewable generation, and the need to comply with new environmental regulations. Although the current trend toward increased use of natural gas and renewable appears fairly robust, there is uncertainty about the factors influencing the fuel mix for electricity generation. AEO2012 includes several cases examining the impacts on coal-fired plant generation and retirements resulting from different paths for electricity demand growth, coal and natural gas prices, and compliance with upcoming environmental rules.

While the Reference case projects 49 gigawatts of coal-fired generation retirements over the 2011 to 2035 period, nearly all of which occurs over the next 10 years, the range for cumulative retirements of coal-fired power plants over the projection period varies considerably across the alternative cases (Figure 5), from a low of 34 gigawatts (11 percent of the coal-fired generator fleet) to a high of 70 gigawatts (22 percent of the fleet). The high-end of the range is based on much lower natural gas prices than those assumed in the Reference case; the lower end of the range is based on stronger economic growth, leading to stronger growth in electricity demand and higher natural gas prices. Other alternative cases, with varying assumptions about coal prices and the length of the period over which environmental compliance costs will be recovered, but no assumption of new policies to limit GHG emissions from existing plants, also yield cumulative retirements within a range of 34 to 70 gigawatts. Retirements of coal-fired capacity exceed the high-end of the range (70 gigawatts) when a significant GHG policy is assumed (for further description of the cases and results, see “Issues in focus”).

Total energy-related emissions of carbon dioxide in the United States stay below their 2005 level through 2035

Energy-related carbon dioxide (CO2) emissions grow slowly in the AEO2012 Reference case, due to a combination of modest economic growth, growing use of renewable technologies and fuels, efficiency improvements, slow growth in electricity demand, and increased use of natural gas, which is less carbon-intensive than other fossil fuels. In the Reference case, which assumes no explicit Federal regulations to limit GHG emissions beyond vehicle GHG standards (although State programs and renewable portfolio standards are included), energy-related CO2 emissions grow by just over 2 percent from 2010 to 2035, to a total of 5,758 million metric tons in 2035 (Figure 6). CO2 emissions in 2020 in the Reference case are more than 9 percent below the 2005 level of 5,996 million metric tons, and they still are below the 2005 level at the end of the projection period. Emissions per capita fall by an average of 1.0 percent per year from 2005 to 2035.

Projections for CO2 emissions are sensitive to such economic and regulatory factors due to the pervasiveness of fossil fuel use in the economy. These linkages result in a range of potential GHG emissions scenarios. In the AEO2012 Low and High Economic Growth cases, projections for total primary energy consumption in 2035 are, respectively, 100.0 quadrillion Btu (6.4 percent below the Reference case) and 114.4 quadrillion Btu (7.0 percent above the Reference case), and projections for energy-related CO2 emissions in 2035 are 5,356 million metric tons (7.0 percent below the Reference case) and 6,117 million metric tons (6.2 percent above the Reference case)”.  (Ref:U.S. Energy Information Administration).

People in the chemical field will understand the concept of ‘irreversibility’. Certain chemical reactions can go only in one direction and but not in the reverse direction. But some reactions can go on either direction and we can manipulate such reactions to our advantages. This concept has been successfully used in designing many chemical reactions in the past and many innovative industrial and consumer products emerged out of it. But such irreversible reactions also have irreversible consequences because it can irreversibly damage the environment we live in. There is no way such damage can be reversed. That is why a new branch of science called ‘Green Chemistry’ is now emerging to address some of the damages caused by irreversible chemical reactions. It also helps to substitute many synthetic products with natural products. In the past many food colors were made out of coal-tar known as coal-tar dyes. These dyes are used even now in many commercial products. Most of such applications were merely based on commercial attractiveness rather than health issues. Many such products have deleterious health effects and few of them are carcinogenic. We learnt from past mistakes and moved on to new products with less health hazards. But the commercial world has grown into a power lobby who can even decide the fate of a country by influencing political leaders. Today our commercial and financial world has grown so powerful that they can even decides who can be the next president of a country rather than people and policies. They can even manipulate people’s opinion with powerful advertisements and propaganda tactics by flexing their financial muscles.

Combustion of fossil fuel is one such example of ‘irreversibility’ because once we combust coal, oil or  gas,  it will be decomposed into oxides of Carbon, oxide of  Nitrogen and also oxides of Sulfur and Phosphorous depending upon the source of fossil fuel  and purification methods used. These greenhouse gases once emitted into the atmosphere we cannot recover them back. Coal once combusted it is no longer a coal. This critical fact is going to decide our future world for generations to come. Can we bring back billions of tons of Carbon we already emitted into the atmosphere from the time of our industrial revolution? Politicians will pretend not to answer these question and financial and industries lobby will evade these question by highlighting the ‘advancement made by industrial revolutions’. People need electricity and they have neither time nor resources to find an alternative on their own. It is open and free for all. People can be skeptical about these issues because it is ‘inconvenient for them’ to change But can we sustain such a situation?

Irreversibility does not confine only to chemical reactions but also for the environment and sustainability because all are intricately interconnected.Minig industries have scared the earth, power plants polluted the air with greenhouse emission and chemical industries polluted water and these damages are irreversible. When minerals become metals, buried coal becomes power and water becomes toxic effluent then we leave behind an earth that will be uninhabitable for our future generations and all the living species in the world. Is it sustainable and can we call it progress and prosperity? Once we lose pristine Nature by our irreversible actions then that is a perfect recipe for a disaster and no science or technology can save human species from extinction. One need not be scientist to understand these simple facts of life. Each traditional land owners such as Aborigines of Australia or Indians of America and shamans of Indonesia have traditionally known and passed on their knowledge for generations. They too are slowly becoming extinct species in our scientific world because of our irreversible actions. Renewability is the key to sustainability because renewability does not cause irreversible damage to Nature.

Renewable Hydrogen offers the most potential energy source of the future for the following reasons. Hydrogen has the highest heat value compared to rest of the fossil fuels such as Diesel, petrol or butane. It does not emit any greenhouse gases on combustion. It can readily be generated from water using your roof mounted solar panels. The electrical efficiency of fuel cell using Hydrogen as a fuel is more than 55% compared to 35% with diesel or petrol engine. It is an ideal fuel that can be used for CHP applications. By properly designing a system for a home, one can generate power as well as use the waste heat to heat or air-condition your home. It offers complete independence from the grid and offers complete insulation from fluctuating oil and gas prices. By installing a renewable Hydrogen facility at your home, you can not only generate Electricity for your home but also fuel your Hydrogen car. The system can be easily automated so that it can take care of your complete power need as well as your fuel requirement for your Hydrogen car. Unlike Electric cars, you can fill two cylinders of a Hydrogen car which will give a mileage of 200miles.You can also charge your electric car with Fuel cell DC power.

Renewable Hydrogen can address all the problems we are currently facing with fossil fuel using centralized power generation and distribution. It will not generate any noise or create any pollution to the environment. It does not need large amount of water. With increasing efficiency of solar panels coming into the market the cost of renewable Hydrogen power will become competitive to grid power. Unlike photovoltaic power, the excess solar power is stored in the form of Hydrogen and there is no need for deep cycle batteries and its maintenance and disposal. It is a one step solution for all the energy problems each one of us is facing. The only drawback with any renewable energy source is its intermittent nature and it can be easily addressed by building enough storage capacity for Hydrogen. Storing large amount of energy is easy compared to battery storage.

The attached ‘You Tube’ video footage show how Solar Hydrogen can be used to power your home and fuel your Hydrogen car. Individual homes and business can be specifically designed based on their power and fuel requirements.

Carbon neutral biomass is becoming a potential alternative energy source for fossil fuels in our Carbon constrained economy. More and more waste –to-energy projects is implemented all over the world due to the availability of biomass on a larger scale; thanks to the increasing population and farming activities. New technological developments are taking place side by side to enhance the quality of Biogas for power generation. Distributed power generation using biogas is an ideal method for rural electrification especially, where grid power is unreliable or unavailable. Countries like India which is predominantly an agricultural country, requires steady power for irrigation as well as domestic power and fuel for her villages. Large quantity of biomass in the form of agriculture waste, animal wastes and domestic effluent from sewage treatment plants are readily available for generation of biogas. However, generation of biogas of specified quality is a critical factor in utilizing such large quantities of biomass. In fact, large quantity of biomass can be sensibly used for both power generations as well as for the production of value added chemicals, which are otherwise produced from fossil fuels, by simply integrating suitable technologies and methods depending upon the quantity and quality of biomass available at a specific location. Necessary technology is available to integrate biomass gasification plants with existing coal or oil based power plants as well as with chemical plants such as Methanol and Urea. By such integration, one can gradually change from fossil fuel economy to biofuel economy without incurring very large capital investments and infrastructural changes. For example, a coal or oil-fired power plant can be easily integrated with a large-scale biomass plant so that our dependency on coal or oil can be gradually eliminated.

Generation of biogas using anaerobic digestion is a common method. But this method generates biogas with 60% Methane content only, and it has to be enriched to more than 95% Methane content and free from Sulfur compounds, so that it can substitute piped natural gas with high calorific value or LPG (liquefied petroleum gas). Several methods of biogas purification are available but chemical-free methods such as pressurized water absorption or cryogenic separation or hollow fiber membrane separation are preferred choices.

The resulting purified biogas can be stored under pressure in tanks and supplied to each house through underground pipelines for heating and cooking. Small business and commercial establishments can generate their own power from this gas using spark-ignited reciprocating gas engines (lean burnt gas engines) or micro turbines or PAFCs (phosphoric acid fuel cells) and use the waste heat to air-condition their premises using absorption chillers. In tropical countries like India, such method of distributed power generation is absolutely necessary to eliminate blackouts and grid failures. By using this method, the rural population need not depend upon the state-owned grid supplies but generate their own power and generate their own gas, and need not depend on the supply of rationed LPG cylinders for cooking. If the volume of Bio-methane gas is large enough, then it can also be liquefied into a liquified bio-methane gas (LBG) similar to LNG and LPG. The volume of biomethane gas will be reduced by 600 times, on liquefaction. It can be distributed in small cryogenic cylinders and tanks just like a diesel fuel. The rural population can use this liquid bio-methane gas as a fuel for transportation like cars, trucks, buses, and farm equipment like tractors and even scooters and auto-rickshaws.

Alternatively, large-scale biomass can be converted into syngas by gasification methods so that resulting biomass can be used as a fuel as well as raw materials to manufacture various chemicals. By gasification methods, the biomass can be converted into a syngas (a mixture of Hydrogen and Carbon monoxide) and free from sulfur and other contaminants. Syngas can be directly used for power generation using engines and gas turbines.

Hydrogen rich syngas is a more value added product and serves not only as a fuel for power generation, but also for cooking, heating and cooling. A schematic flow diagram Fig 3,  Fig4 and Fig 6 (Ref: Mitsubishi Heavy Industries Review) shows how gasification of biomass to syngas can  compete with existing fossil fuels for various applications such as for power generation, as a raw material for various chemical synthesis and as a fuel for cooking, heating and cooling and finally as a liquid fuel for transportation. Bio-gasification has a potential to transform our fossil fuel dependant world into Carbon-free world and to help us to mitigate the global warming.

Batteries have become indispensable for energy storage in renewable energy systems such as solar and wind. In fact the cost of battery bank, replacements, operation and maintenance will exceed the cost of PV solar panels for off grid applications during the life cycle of 20 years. However, batteries are continued to be used by electric power utilities for the benefits of peak shaving and load leveling. Battery energy storage facilities give the dynamic benefits such as voltage and frequency regulation, load following, spinning reserve and power factor correction along with the ability to give peak power.

Fuel cell power generation is another attractive option for providing power for electric utilities and commercial buildings due to its high-efficiency and environmentally friendly nature. This type of power production is especially economical, where potential users are faced with high cost in electric power generation from coal or oil, or where environmental constraints are stringent, or where load constraints of transmission and distribution systems are so tight that their new installations are not possible. Both batteries and fuel cells have their own unique advantages to electric power systems. They also contain a great potential to back up severe PV power fluctuations under varying weather conditions.

Photovoltaic power outputs vary depending mainly upon solar insolation and cell temperature.  PV power generator may sometimes experience sharp fluctuations owing to intermittent weather conditions, which causes control problems such as load frequency control, generator voltage control and even system stability.  Therefore there is a need for backup power facilities in the PV power generation.   Fuel cells and batteries are able to respond very fast to load changes because their electricity is generated by chemical reactions. A 14.4kW lead acid battery running at 600A has greatest load gradient of 300 A/sec, a phosphoric-acid fuel cell system can match a demand that varies by more than half its rated output within 0.1 second. The dynamic response time of a 20kW solid-oxide fuel cell power plant is less than 4 second when a load increases from 1 to 100%, and it is less than 2 msec when a load decreases from 100 to 1%.  Factory assembled units provides fuel cell and battery power plants with short lead-time from planning to installation. This modular production enables them to be added in varying increments of capacity, to match the power plant capacity to expected load growth. In contrast, the installation of a single large conventional power plant may produce excess capacity for several years, especially if the load growth rate is low.  Due to their multiple parallel modular units and absence of combustion and electromechanical rotary devices, fuel cell and battery power plants are more reliable than any other forms of power generation. Fuel cells are expected to obtain performance reliability near 85%. Consequently, a utility that installs a number of fuel cell or battery power plants is able to cut its reserve margin capacity while maintaining a constant level of the system reliability. The electrochemical conversion processes of fuel cells and batteries are silent because they do not have any major rotating devices or combustion.  Water requirement for their operation is very little while conventional power plants require a massive amount of water for system cooling.

Therefore, they can eliminate water quality problems created by the conventional plants’ thermal discharges. Air pollutant emission levels of fuel cells and batteries are none or very little. Emissions of SO2 and NOx in the fuel cell power plant are 0.003 lb/MWh and 0.0004 lb/MWh respectively. Those values are projected to be about 1,000 times smaller than those of fossil-fuel power plants since fuel cells do not rely on combustion process. These environmentally friendly characteristics make it possible for those power plants to be located close to load centers in urban and suburban area. It can also cut energy losses and costs associated with transmission and distribution equipment. Their site near load centers may also cut the likelihood of power outage.

Electricity is produced in a storage battery by electro-chemical reactions. Similar chemical reactions take place in a fuel cell, but there is a difference between them with respect to fuel storage. In storage batteries chemical energy is stored in the positive/negative electrodes of the batteries. In fuel cells, however, the fuels are stored externally and need to be fed into the electrodes continuously when the fuel cells are operated to generate electricity.

Power generation in fuel cells is not limited by the Carnot Cycle in the view that they directly convert available chemical free energy to electrical energy than going through combustion processes.  Therefore fuel cell is a more efficient power conversion technology than the conventional steam-applying power generations. Fuel cell is a one-step process to generate electricity, the conventional power generator has several steps for electricity generation and each step incurs a certain amount of energy loss. Fuel cell power systems have around 40-60% efficiencies depending on the type of electrolytes. For example, the efficiencies of phosphoric-acid fuel cells and molten-carbonate fuel cells are 40-45% and 50-60%, respectively. Furthermore, the fuel cell efficiency is usually independent of size; small power plants run as efficiently as large ones. Battery power systems themselves have high energy efficiencies of nearly 80%, but their overall system efficiencies from fuel through the batteries to converted ac power are reduced to below 30%. This is due to energy losses taking place when one energy form is converted to another

A battery with a rated capacity of 200Ah battery will give less than 200 Ah. At less than 20A of discharge rates, the battery will give more that 200 Ah. The capacity of a battery is specified by their time rate of discharge. As the battery discharges, its terminal voltage, the product of the load current and the battery internal resistance gradually decreases. There is also a reduction in battery capacity with increasing rate of discharge. At 1-hr discharge rate, the available capacity is only 55% of that obtained at 20-hr rate. This is because there is insufficient time for the stronger acid to replace the weak acid inside the battery as the discharge proceeds.   For fuel cell power systems, they have equally high-efficiency at both partial and full loads. The customer’s demand for electrical energy is not always constant. So for a power utility to keep adjustment to this changing demand, either large base-load power plants must sometimes run at part load, or smaller peaking units must be used during periods of high demand. Either way, efficiency suffers or pollution increases. Fuel cell systems have a greater efficiency at full load and this high-efficiency is retained as load diminishes, so inefficient peaking generators may not be needed.

Fuel cells have an advantage over storage batteries in the respect of operational flexibility. Batteries need several hours for recharging after they are fully discharged. During discharge the batteries’ electrode materials are lost to the electrolyte, and the electrode materials can be recovered during the recharging process. Over time there is a net loss of such materials, which may be permanently lost when the battery goes through a deep discharge. The limited storage capacity of the batteries implies that it is impossible for them to run beyond several hours.

Fuel cells do not undergo such material changes. The fuel stored outside the cells can quickly be replenished, so they do not run down as long as the fuel can be supplied.   The fuel cells show higher energy density than the batteries when they run for more than 2 hours. It means that fuel cell power systems with relatively small weight and volume can produce large energy outputs. That will give the operators in central control centers for the flexibility needed for more efficient use of the capital-intensive fuel cell power plants.

In addition, where hydrogen storage is possible, renewable power sources can drive an electrolysis process to produce hydrogen gas during off-peak periods that will be used to run the fuel cells during peak demands. The usage of storage batteries in an electric utility industry is expected to increase for the purposes of load leveling at peak loads, real-time frequency control, and stabilizing transmission lines. When integrated with photovoltaic systems, the batteries are required to suppress the PV power fluctuations due to the changes of solar intensity and cell temperature. The fact that the PV power outputs change sharply under cloudy  weather conditions makes it hard to decide the capacity of the battery power plants since their discharging rates are not constant. For a lead-acid battery, the most applicable battery technology for photovoltaic applications to date, the depth of discharge should not exceed 80% because the deep discharge cycle reduces its effective lifetime. In order to prevent the deep discharge and to supplement varying the PV powers generated on cloudy weather days, the battery capacity must be large. Moreover, the large battery capacity is usually not fully used, but for only several days. Fuel cells integrated with photovoltaic systems can give smoother operation. The fuel cell system is capable of responding quickly enough to level the combined power output of the hybrid PV-fuel cell system in case of severe changes in PV power output. Such a fast time response capability allows a utility to lower its need for on-line spinning reserve. The flexibility of longer daily operation also makes it possible for the fuel cells to do more than the roles of gas-fired power plants. Gas turbines are not economical for a purpose of load following because their efficiencies become lower and operating costs get higher at less than full load conditions

Fuel cell does not emit any emission except water vapor and there is absolutely no carbon emission.  However, storage batteries themselves do not contain any environmental impacts even though the battery charging sources produce various emissions and solid wastes. When an Electrolyzer is used to generate Hydrogen on site to fuel the Fuel cell, the cost of the system comes down due to much reduction in the capacity of the battery. The specific cost of energy and NPC is lower than fully backed battery system.

During dismantling, battery power plants require a significant amount of care for their disposal to prevent toxic materials from spreading around. All batteries that are commercially viable or under development for power system applications contain hazardous and toxic materials such as lead, cadmium, sodium, sulfur, bromine, etc. Since the batteries have no salvage value and must be treated as hazardous wastes, disposal of spent batteries is an issue. Recycling batteries is encouraged and not placing them in a landfill. One method favoring recycling of spent batteries is regulation. Thermal treatment for the lead-acid and cadmium-containing batteries is needed to recover lead and cadmium. Sodium-sulfur and zinc bromine batteries are also required to be treated before disposal.

Both batteries and fuel cells are able to respond very fast to system load changes because they produce electricity by chemical reactions inside them. Their fast load-response capability can nicely support the sharp PV power variations resulted from weather changes.  However, there are subtle different attributes between batteries and fuel cells when they are applied to a PV power backup option. Power generation in fuel cell power plants is not limited by the Carnot Cycle, so they can meet high power conversion efficiency. Even taking into account the losses due to activation over potential and ohmic losses, the fuel cells still have high efficiencies from 40% to 60%. For example, efficiencies of PAFCs and MCFCs are 40-45% and 50-60% respectively. Battery power plants, however, themselves have high energy efficiency of nearly 80%, but the overall system efficiency from raw fuel through the batteries to the converted ac power is reduced to about 30%.

A battery’s terminal voltage gradually decreases as the battery discharges due to a proportional decrease of its current. A battery capacity reduces with increasing rate of discharge, so its full capacity cannot be used when it discharges at high rates. On the other hand, fuel cell power plants have equally high-efficiency at both partial and full loads. This feature allows the fuel cells to be able to follow a changing demand without losing efficiency. The limited storage capacity of batteries indicates that it is impossible for them to run beyond several hours. The batteries when fully discharged need several hours to be recharged.

For its use in PV power connections, it is as hard   to estimate the exact capacity of the batteries. In order to prevent the batteries’ deep discharge and to supplement the varying PV powers on some cloudy weather days, the battery capacity should be large, but that large capacity is not fully utilized on shiny days. For fuel cells, they do not contain such an operational time restriction as long as the fuel can be supplied. Thus, the fuel cell power plants can give operational flexibility with the operators in central control centers by utilizing them efficiently. As intermediate power generation sources, fuel cell power plants may replace coal-fired or nuclear units under forced outage or on maintenance. For the PV power backup the batteries’ discharge rate is irregular and their full capacity may usually not be consumed. So, it is difficult to design an ideal capacity of the battery systems for support of the PV power variations and to economically run them. Instead of batteries fuel cell power plants show diverse operational flexibility for either a PV power backup or a support of power system operation.

 

As the threat of global warming looms large, Governments and Industries are looking for innovative, alternative and renewable energy sources and energy efficiency solutions. But how many alternative energy sources are available and what are their potentials? How to cut our carbon footprint without making larger new investment? How to improve the energy efficiency of the existing systems so that we can increase energy output for the same amount of fuel input and cut the cost of energy? These are some of the fundamental questions Governments and industries are grappling with, for the past few years. We are used to generating cheap energy from coal, oil and gas at the cost of the environment for several decades. We are used to water supply free of cost or at negligible cost for several decades. Governments were able to survive year after year because they were able to supply these two fundamental requirements of the people namely, energy and water at low-cost. But this situation changed swiftly when scientists raised the alarm bells on carbon emission and global warming. Still many Governments, especially industrialized countries with large energy and water usage, are still playing ‘wait and watch’ game, because they cannot afford to increase the tariffs on power and water. Any such increase will make Governments unpopular and their re-election to the office doubtful.

The real alternative to fossil fuels is only solar energy, which is clean, reliable and abundant. All other forms of renewable sources such as wind, geothermal, ocean thermal energy and wave energy are only offshoot of solar energy. The prime source is still the sun and the source of energy is from the chain nuclear fusion reaction of Hydrogen atom. The radiation of this nuclear reaction in the sun has to travel an average distance of 93 million miles to reach the earth, yet it is enough to meet current energy need of  entire humanity by a factor of 20,000 times. But to convert sun’s light and heat energy into Electricity and other useful forms of energy, we need some rare materials which we never used in the past. They are called ‘rare earth materials’ because their available sources and supplies are rare on planet earth. But these exotic and rare earth materials are becoming indispensable in the development of renewable energy products and applications. The future growth of clean energy technologies depend on supply of such rare earth materials.

Fourteen elements and related materials were selected for a criticality assessment by US Government department of energy. Eight of these are rare earth metals, which are valued for their unique magnetic, optical and catalyst properties. The materials are used in clean energy technologies as follows. Lanthanum, cerium, praseodymium, neodymium, cobalt and lithium are used in electric vehicle batteries. Neodymium, praseodymium and dysprosium are used in magnets for electric vehicles and wind turbines. Samarium is also used in magnets. Lanthanum, cerium, europium, terbium and yttrium are used in phosphors for energy-efficient lighting. Indium, gallium and tellurium are used in solar cells. The materials were selected for study based on factors contributing to risk of supply disruption.

Though usage of such material is relatively small, it is anticipated that the growth of clean technologies will need a substantial quantity of these materials. Currently China is endowed with almost 95% of such rare materials in the world. These materials are available in the form of ores and minerals under the earth. They have to be mined, processed and extracted in a pure form so that they can be used in developing clean energy products of the future. We will discuss about such products and technologies in our future articles. The anomaly is the energy required to mine, process and extract these rare earth materials need energy and such energy to have to come only from the sun. It is once again Nature that comes to the rescue of human beings at such critical junctures.

 

We  acknowledge that solar energy is a potential renewable energy source of the future. The total energy need of the world is projected in the next 40 years to be 30 TW (terra watts) and only solar energy has a potential to meet the above demand. However, harnessing sun’s energy to its fullest potential is still a long way to go. Concentrated solar power (CSP) offers a greater hope to fill this gap. The main reason is the cost  advantage of CSP compared to PV solar and energy storage technologies and their costs.

The cost of PV solar has steadily decreased in the past few years. Though the cost of solar cell has come down to $0.75 per watt, the overall cost of the PV system is still around $ 3.00 per watt. This is due to the cost of encapsulation; interconnect wiring, mounting of panels, inverters and battery bank. The overall cost of the system will not come down drastically beyond a point. This makes PV solar still more expensive compared to conventional power generation using fossil fuels. People can understand the value of renewable energy and impending dangers of global warming due to greenhouse gases, but the final cost of energy will decide the future of energy sources.

In PV solar the sun’s light energy is directly converted into Electricity, but storing such energy using batteries have certain limitations. PV solar is suitable for small-scale operations but it may not be cost-effective for large-scale base load power generation. The best option will be to harness the sun’s thermal energy and store them and use them to generate power using the conventional and established methods such as steam or gas turbines. Once we generate thermal energy of required capacity then we have number of technologies to harness them into  useful forms. As we mentioned earlier, the thermal energy can trigger a chemical reaction such as formation of Ammonia by reaction between Hydrogen and Nitrogen under pressure, which will release a large amount of thermal energy by exothermic reaction. Such heat can be used to generate steam to run a stem turbine to generate power. The resulting ammonia can be split with concentrated solar power (CSP) into Hydrogen and Nitrogen and the above process can be repeated.

The same system can also be used to split commercial Ammonia into Hydrogen and Nitrogen. The resulting Hydrogen can be separated and stored under pressure. This Hydrogen can be used to fuel Fuel cell cars such as Honda FXC or to generate small-scale power for homes and offices.

By using CSP, there is potential of cost savings as much as 70% compared to PV solar system for the same capacity power generation on a larger scale. Focusing sun’s energy using large diameter parabolic troughs and concentrators, one can generate high temperatures.  Dishes can typically vary in size and configuration from a small diameter of perhaps 1 meter to much larger structures of a dozen or more meters in diameter.  Point focus dish concentrators are mounted on tracking systems that track the sun in two axes, directly pointing at the sun, and the receiver is attached to the dish at the focal point so that as the dish moves, the receiver moves with it.  These point focus systems can generate high temperatures exceeding 800ºC and even 1,800ºC.

The temperature required to run a steam turbine does not exceed 290C and it is quite possible to store thermal energy using mixture of molten salts with high Eutectic points and use them to generate steam. Such large-scale energy storage using lead-acid batteries and power generation using PV solar may not be economical. But it will be economical and technically feasible to harness solar thermal energy using CSP for large-scale base load power generation. It is estimated that the cost of such CSP will compete with traditional power generation using coal or oil in the near future.CSP has potential to generate cost-effective clean power as well as a fuel for transportation.

The city of Athens hosted its oldest tradition of lighting the Olympic torch for the 2012 London Olympic Games on Thursday in Olympia. The torch was lit by solar power; using parabolic mirror to redirect the sun’s light to light the flame with purest natural light. The thermal energy of sun’s light can be powerful when focused to a point and it can reach a temperature as much as 600C.The parabolic trough with reflective mirror focuses the sunlight on the tube called ‘collectors’ in which a fluid with high boiling point is circulated. The hot fluid in turn is used to convert water into steam in boiler. The hot oil transfers its heat to the water in a heat exchanger and returns back to the parabolic trough. It is a closed circuit system. The hot oil at 390C generates steam at 370C at 100 bar pressure, which is used to run a HP steam turbine. The standard steam condensing cycle generates power similar to fossil fuel fired power plant. A 50 Mw Trough plant in Israel (Negev Desert) is already in operation.

The capacity of such plant can be easily expanded by adding modular parabolic troughs and collectors and the plant can be designed to meet  specific power demands. This is a straight forward method to generate base load power using standard steam cycle. The efficiency of such system will be 41% maxium.However recently few companies are trying use a combined cycle. This increase the solar to heat efficiency from 50.5% to 53.6%.This nominal 50Mw power plant generates  a total peak power of 57.10Mw using a solar collection area of 310,028m2 with annual solar to electrical efficiency at 16.3% using a water-cooled condenser in the steam cycle. The cost of energy works out to $0.23 to $ 0.25 /kwhrs.

By using a central solar collection tower (Heliostat) and bottoming with Rankin/Kalina cycle ,it is estimated that the total installed cost can be reduced by 10%.The system can be configured from 2Mw up to 100Mw using both trough and tower system. The system can be installed in any remote, arid locations using air condensers, where cooling water is a problem. The estimated annual specific energy cost is less than 6 cents/kwhrs, comparable to low-cost fossil energy but with zero pollution and with zero carbon emission.

Solar thermal is a potential clean energy of the future for many countries around the world with yearlong sunshine with good intensisty.The solar thermal energy can also be used in many process industries where thermal heating is required. Solar salt pans can use solar thermal energy very efficiently to cut their production cycle. The concentrated brine can be used as a circulation fluid in solar collectors and also be used to generate power using low heat technologies like Kalina cycle, because concentrated salt brine can store thermal heat.

Gemasolar power in Spain is a base load power station supplying power for 25,000 homes 24×7 using molten salt (60% KNO3+40% NaNO3) as a thermal storage medium instead of batteries. Nine plants were built in 1980 in Mojave Desert with a combined capacity of 354 Mws.

Other examples of solar base load power plants are Blythe solar with capacity of 968Mw at Riverside County, California and Ivanpah power station with capacity of 370 Mw capacities in US. Large scale solar base load plants are no longer a theory but a commercial reality.

Direct solar lighting is also being introduced using fiber optics. The sun light is collected at a central point and directed through fiber optics to various rooms inside the building supplying direct sun light. This saves not only electricity but also provides natural light to work places because human body requires a certain amount of UV light exposure. Solar energy is here to stay and offer various clean energy solutions in the future.

 

 

%d bloggers like this: