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Showing posts with label wind energy. Show all posts
Showing posts with label wind energy. Show all posts

Wednesday, April 19, 2017

CAPZ desalination technology uses only Sun,Sea and WInd !


CAPZ (Clean water at affordable price with zero discharge) is a new desalination concept that separates seawater into fresh drinking water and industrial salt both simultaneously using only sun and wind power. Seawater is nothing but fresh water in abundance with valuable mineral salts dissolved in it. These minerals include Sodium, Potassium, Lithium and Magnesium and a host of other minerals in traces. It requires a holistic approach to separate them in their pure form along with fresh water for potable and industrial applications. CAPZ technology precisely attempts to do that so that the seawater intake can be put into huge economic usage while reducing or eliminating completely the discharge of highly saline effluent contaminated with chemicals back into the sea. With increasing demand for fresh water and depleting sources of fresh water due to natural and man-made causes , sea water has become an important source for fresh drinking water. Sea water is not only a source of fresh water but also a new source of clean Hydrogen an energy of the future. It requires only sun ,sea and wind to achieve this!

Sunday, December 2, 2012

Which is the best storage technology for Renewable energy?

The share of renewable energy is steadily increasing around the world. But storing such intermittent energy source and utilizing it when needed has been a challenge. In fact energy storage constitutes a significant portion of the cost in any renewable energy technology. Many storage technologies are currently available in the commercial market, but choosing a right type of technology has always been a difficult choice. In this article we will consider four types of storage technologies. The California Energy Commission conducted economic and environmental analyses of four energy storage options for a wind energy project: (1) lead acid batteries, (2) zinc bromine (flow) batteries, (3) a hydrogen electrolyzer and fuel cell storage system, and (4) a hydrogen storage option where the hydrogen was used for fueling hydrogen powered vehicle. Their conclusions were: ”Analysis with NREL’s (National Renewable Energy laboratory) HOMER model showed that, in most cases, energy storage systems were not well utilized until higher levels of wind penetration were modeled (i.e., 18% penetration in Southern California in 2020). In our scenarios, hydrogen storage became more cost-effective than battery storage at higher levels of wind power production, and using the hydrogen to refuel vehicles was more economically attractive than reconverting the hydrogen to electricity. The overall value proposition for energy storage used in conjunction with intermittent renewable power sources depends on multiple factors. Our initial qualitative assessment found the various energy storage systems to be environmentally benign, except for emissions from the manufacture of some battery materials. However, energy storage entails varying economic costs and environmental impacts depending on the specific location and type of generation involved, the energy storage technology used, and the other potential benefits that energy storage systems can provide (e.g., helping to optimize Transmission and distribution systems, local power quality support, potential provision of spinning reserves and grid frequency regulation, etc.)”. Key Assumptions Key assumptions guiding this analysis include the following: • Wind power will expand in California under the statewide RPS program to a level of approximately 10% of total energy provided in 2010 and 20% by 2020, with most of this expansion in Southern California. • Costs of flow battery systems are assumed to decline somewhat through 2020 and costs of hydrogen technologies (electrolyzers, fuel cell systems, and storage systems) are assumed to decline significantly through 2020. • In the case where hydrogen is produced, stored, and then reconverted to electricity using fuel cell systems, we assume that the hydrogen can be safely stored in modified wind turbine towers at relatively low pressure at lower costs than more conventional and higher-pressure storage. • In the case where hydrogen is produced and sold into transportation markets, we assume that there is demand for hydrogen for vehicles in 2010 and 2020, and that the Hydrogen is produced at the refueling station using the electricity produced from wind farms (in other words, we assume that transmission capacity is available for this when needed)? Key Project Findings Key findings from the HOMER model projections and analysis include the following: • Energy storage systems deployed in the context of greater wind power development were not particularly well utilized (based on the availability of “excess” off-peak electricity from wind power), especially in the 2010 time frame (which assumed 10% wind penetration statewide), but were better utilized–up to 1,600 hours of operation per year in some cases–with the greater (20%) wind penetration levels assumed for 2020. • The levelized costs of electricity from these energy storage systems ranged from a low of $0.41 per kWh—or near the marginal cost of generation during peak demand times—to many dollars per kWh (in cases where the storage was not well utilized). This suggests that in order for these systems to be economically attractive, it may be necessary to optimize their output to coincide with peak demand periods, and to identify additional value streams from their use (e.g., transmission and distribution system optimization, provision of power quality and grid ancillary services, etc.) • At low levels of wind penetration (1%–2%), the electrolyzer/fuel cell system was either inoperable or uneconomical (i.e., either no electricity was supplied by the energy storage system or the electricity provided carried a high cost per MWh). • In the 2010 scenarios, the flow battery system delivered the lowest cost per energy stored and delivered. • At higher levels of wind penetration, the hydrogen storage systems became more economical such that with the wind penetration levels in 2020 (18% from Southern California), the hydrogen systems delivered the least costly energy storage. • Projected decreases in capital costs and maintenance requirements along with a more durable fuel cell allowed the electrolyzer/fuel cell to gain a significant cost advantage over the battery systems in 2020. • Sizing the electrolyzer/fuel cell system to match the flow battery system’s relatively high instantaneous power output was found to increase the competitiveness of this system in low energy storage scenarios (2010 and Northern California in 2020), but in scenarios with higher levels of energy storage (Southern California in 2020), the Electrolyzer/fuel cell system sized to match the flow battery output became less competitive. • In our scenarios, the hydrogen production case was more economical than the Electrolyzer/fuel cell case with the same amount of electricity consumed (i.e., hydrogen production delivered greater revenue from hydrogen sales than the electrolyzer/fuel cell avoided the cost of electricity, once the process efficiencies are considered). • Furthermore, the hydrogen production system with a higher-capacity power converter and electrolyzer (sized to match the flow battery converter) was more cost-effective than the lower-capacity system that was sized to match the output of the solid-state battery. This is due to economies of scale found to produce lower-cost hydrogen in all cases. • In general, the energy storage systems themselves are fairly benign from an environmental perspective, with the exception of emissions from the manufacture of certain components (such as nickel, lead, cadmium, and vanadium for batteries). This is particularly true outside of the U.S., where battery plant emissions are less tightly controlled and potential contamination from improper disposal of these and other materials are more likely. The overall value proposition for energy storage systems used in conjunction with intermittent renewable energy systems depends on diverse factors. • The interaction of generation and storage system characteristics and grid and energy resource conditions at a particular location. • The potential use of energy storage for multiple purposes in addition to improving the dependability of intermittent renewable (e.g., peak/off-peak power price arbitrage, helping to optimize the transmission and distribution infrastructure, load-leveling the grid in general, helping to mitigate power quality issues, etc.) • The degree of future progress in improving forecasting techniques and reducing prediction errors for intermittent renewable energy systems • Electricity market design and rules for compensating renewable energy systems for their output Conclusions “This study was intended to compare the characteristics of several technologies for providing Energy storage for utility grids—in a general sense and also specifically for battery and Hydrogen storage systems—in the context of greater wind power development in California. While more detailed site-specific studies will be required to draw firm conclusions, we believe those energy storage systems have relatively limited application potential at present but may become of greater interest over the next several years, particularly for California and other areas that is experiencing significant growth in wind power and other intermittent renewable. Based on this study and others in the technical literature, we see a larger potential need for energy storage system services in the 2015–2020 time frames, when growth in renewable produced electricity is expected to reach levels of 20%–30% of electrical energy supplied. Depending on the success in improved wind forecasting techniques and electricity market designs, the role for energy storage in the modern electricity grids of the future may be significant. We suggest further and more comprehensive assessments of multiple energy storage technologies for comparison purposes, and additional site- and technology-specific project assessments to gain a better sense of the actual value propositions for these technologies in the California energy system. This project has helped to meet program objectives and to benefit California in the Following ways: • Providing environmentally sound electricity. Energy storage systems have the Potential to make environmentally attractive renewable energy systems more competitive by improving their performance and mitigating some of the technical issues associated with renewable energy/utility grid integration. This project has identified the potential costs associated with the use of various energy storage technologies as a step toward understanding the overall value proposition for energy storage as a means to help enable further development of wind power (and potentially other intermittent renewable resources as well). • Providing reliable electricity. The integration of energy storage with renewable energy esources can help to maintain grid stability and adequate reserve margins, thereby contributing to the overall reliability of the electricity grid. This study identified the potential costs of integrating various types of energy storage with wind power, against which the value of greater reliability can be assessed along with other potential benefits. • Providing affordable electricity. Upward pressure on natural gas prices, partly as a function of increased demand, has significantly contributed to higher electricity prices in California and other states. Diversification of electricity supplies with relatively low-cost sources, such as wind power, can provide a hedge against further natural gas price increases. Higher penetration of these other (non-natural-gas-based) electricity sources, Potentially enabled by the use of energy storage, can reduce the risks of future electricity.” (Source: California Energy Commission prepared by University of Berkeley).

Thursday, March 22, 2012

Solar energy storage with Battery or Hydrogen?

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 number of changes over a period of 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 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 currently 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 currently 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. The sheer weight of these batteris, space required to install them, capacity utilization, capacity constraints, regular requirement of 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 maintenance of such batteries. Life of a battery is critical because when you calculate the cost of energy over the life cycle of 25 years, the number of replacements of batteries 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 any 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 was also grid independent, but solar power was 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 previous 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 number of 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 maintain 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.

Wednesday, March 14, 2012

Wind energy-that can save islands

Wind is a potential source of renewable energy, especially for islands with an average wind velocity of 5mts/sec and above. Many islands in pacific ocean have some common problems like sea erosion, shortage of power and drinking water. These small islands with little population are fully depending on diesel fuel. In fact their life depends on diesel fuel and any increase in price significantly affects their daily life. Their main source of income is only by fishing and they live day to day. I had a personal experience of visiting a small island off Port Moresby in Papua New Guinea. They call it Daugo Island or ‘Fisherman’s island’ with population of less than 700 people. It is about 4.5km wide and 2km long. It is a coral atoll pushed out of the sea. One can take stroll on the beach and it is one of the most beautiful experiences one can have. It gives a feeling that you are far away from the rest of the world. There is a small abandoned World War II Airfield. The people in the island do not have any electricity or drinking water, and most of them are fishing on small boats. Their boats are fuelled by diesel. They will go to nearby city of Port Moresby and sell their fish and with that money they will buy drinking water and diesel in cans, and return to the island. This is their daily life. Such an island is an ideal location to set up a wind turbine and a small sea water desalination plant, that can easily solve their problem of water and power. The trade wind from the Coral Sea in the island of Papua New Guinea blows almost 7-8 months in a year and their wind velocity averages 7 mts/sec. Two wind turbines of each 250 kW capacity and a small seawater desalination SWRO plant of capacity 15,000lts/day will be sufficient to solve their problems. The desalination plant will consume about 4.5Kwhrs/m3 of water generated. About 2000 kwhrs/day of power can be supplied to the village, each family consuming about 2.85 kwhrs/day for 6 hours/day and also for the desalination plant. The system will generate surplus power. Renewable wind energy is the best option for such islands to generate on-site power and also to desalinate seawater for supply of drinking water. With increasing global warming and sea level rising, these small island face seawater intrusion and inundation. Many islands are slowly disappearing into the vast sea. Moreover, these islands are the most vulnerable to the fluctuating diesels prices and they are walking on a tight rope.Industrialised countries with an average power consumption of several kilowatt hours per day are crying foul about rising energy cost while people in such small islands barely manage their food and shelter after paying for the diesel. Recently the Government of Maldives conducted their cabinet ministers meeting under the sea, to showcase their plight due to sea level rise caused by global warming, to the rest of the world. Small islands can cry loud but their voice is muffled by roaring sea, while rest of the world carries on their business as usual.