Operation and Sizing of Energy Storage for Wind Power Plants in a Market - Term Paper Example

Sur Operation and Sizing of Energy Storage for Wind Power Plants in a Market Introduction: Wind power technology has been into existence since a long time. Wind machines are used to control the power of the wind (Blabbjerg and Chen 11-13). The demand for rural energy supply in the present times requires more and more of smaller machines. The use of such machines is still limited in the developing countries. The machines provide power for lighting, televisions, radios, along with other applications such as water pumping, power supply for telecommunications, and irrigation (Wind Electricity Generation). Wind energy provides a priceless supplement for the energy sources available conventionally across the world. However, the sporadic nature of wind energy limits the maximum penetration of wind power that can be made available for the networks of electricity (Korpas, Hildrum and Holen 1). Also, since production in wind power experiences significant fluctuations, it becomes difficult for the owners of the wind power plants to sustain against the competition in the emerging markets of electricity. Some of the significant factors in relation to the operation and sizing of energy storage for wind power plants in a market include the impact of the mechanisms of the electricity markets, constraints of the transmission line, and forecast of the accuracy of the wind power. These factors together determine the advantages and disadvantages of the storage of wind power. Considering all these issues, a computer model has been developed to achieve the scheduling and operation of the resources being distributed in the market system (Korpas, Hildrum and Holen 1). The present study discusses on the operation and sizing of the energy storage for wind power plants in a market. Energy Storage for Wind Power Plants in a Market: Irregular supply has been obtained as the most significant problem that hinders the development of renewable power market (Pielke). Continuous refinement of technologies is being processed trying to ensure that developments such as wind turbines would be able to fill the gap in between decommissioned fossil fuel and nuclear plants. However, the processes require significant amount of investment and suitable conditions (Lo). In case of generation of excess electricity, often wastage occurs. Countries like the United Kingdom (UK) have reported huge payments for power that remained unused since the year 2011. The cost of such unused power shifts on to those who pay the taxes. Continuous research is being conducted to determine the causes of a marketplace leading to power wastage. Over the years, greater attention has been drawn on the hydro-electric storage and use of more modern battery and fuel cell systems. Cryogenic energy storage (CES) has been obtained as one of the most effective measures for capture and storage of electricity, the process being highly innovative and new. It is expected that CES will be able to solve the current problems of wind power storage of energy (Lo). Hydro-Storage for Wind Power Energy: It is being researched and suggested that higher rates of pumped hydro storage would benefit the storage of wind power. This process enables storage of energy through water being pumped from a low reservoir to a reservoir located at a higher location. The method is applied in case of excess of energy. In case of wind energy, this is helpful when wind blows hard at the nights. Thus when the energy is needed, the valves of the storage can be opened up and the water can be allowed to run through the wind turbines. This is a process similar to all hydro stations (Richard). Cryogenic energy storage (CES) for Wind Power Energy Storage: As discussed, one of the most prominent problems in regard to the storage of wind power energy is the intermittency of the power, making the issue of energy storage highly critical. Engineers have in the present times focused on cryogenic energy storage where they have established technology trying to create a modular, scalable and a comparatively cheap system dense with energy, the location of which would be next to the infrastructure such that it can be easily located and accessed when in need. It is capable of storing energy without making use of reservoirs or mountains. About 50 percent of the energy that is used as the input for the system is returned by this technology, thereby allowing the efficiency of the system to rise to around 70 percent for the storage of wind power, particularly when it makes use of waste power from any power station (Harris). Batteries are mostly used for storage of wind power owing to their low costs and lesser impacts on the environment (Pistoia 475-477). Researchers have experimented the use of batteries for the storage purpose and compared it with the other technologies available for storage that include compressed air systems, cryogenic energy storage, freewheelers, and so on in order to determine the best method for storage. CES has proved to be one of the most promising technologies of the current century available for the storage of wind power energy. The technology has been developed by Highview Power Storage located in the UK. It represents the world’s first model for storage of liquid air energy storage system. The uniqueness of the system is that the air in the system remains free and the supply of the power is infinite hence providing the use of liquid form of the wind energy as a highly attractive solution for its users (UK university to set up new Centre for Cryogenic Energy Storage). Thus with the use of liquid air, the storage of wind power energy has been made possible by the CES. The above figure presents the concept and system of CES for wind power energy storage (Coxworth). Operation and Sizing of Energy Storage for Wind Power Plants in a Market: More and more researches are being conducted trying to make use of the energy storage in raising the value of the intermittent sources of energy as available in the electricity markets. The use of a computer model enables schedule and operation of the sources that are distributed and developed in the market. The diagram on the right illustrates the components of the system and the electricity market model (Korpaas, Holen and Hildrum 599-606). The calculation of the power output of the power plant is obtained from the power curve as presented in the following figure (Korpaas, Holen and Hildrum 599-606): Considering electricity spot market, say the Nordic spot market, there are daily bids for sale and purchase of energy made available in the pool of power. The spot price of the energy gets settled followed by working out the final schedule for the power generators. Specified amounts need to be delivered on time otherwise which discrepancies might occur and will need to be settled resulting in reduction of the level of the income. The calculation of the annual revenue is obtained from the following equation (Korpaas, Holen and Hildrum 599-606): AR = ?year (fspot + floss + fload + freg) Where, AR = annual revenue; fspot is the hourly income from the spot market; floss is the loss caused by power flow in the line of transmission; fload is the load income that represents the cost for the supply of the electricity load from an external grid, the payment of which is done by the spot price; and freg represents the proportional prices of the sales and purchases of the power as calculated to the spot price (Korpaas, Holen and Hildrum 599-606). The difference between the spot price and the regulating price can be determined from the following figure (Korpaas, Holen and Hildrum 599-606): The Operation Strategy: There are three main parts of the operation system that include forecasting the velocity of the wind, creating a schedule between the power exchange and the market, and the on-line operation of the storage. The flowchart presenting the model of the operation strategy is on the right (Korpaas, Holen and Hildrum 599-606). The forecasting function needs to be performed every day primarily before the scheduling of the operation is done. The mean data is calculated along with the coefficient of variation of the prediction of the mean wind velocity. The mean wind velocity is then calculated. A random number is then drawn from the normal distribution considering mean and standard deviation followed by return of the predicted wind velocity (Korpaas, Holen and Hildrum 599-606). With penalties implemented for deviations in bids in the power market, wind energy can be made used to for the compensation of imbalanced occurring in energy as the predictability of the wind power is limited. Increased participation of the wind power in the electricity markets have been noted in the present times that has led to significant uncertainties for the management of the energy portfolios. In order to decide on the operation and sizing of the wind energy storage for wind power plants in markets, the forecast of the uncertainties need to be clearly represented (Pinson et al 1-7). Such representation would include probabilities of possible generation of the wind energy and power as well as data on the correlation of the forecast information and errors. Considering the electricity markets, the size and operation are actually determined by the imbalances and the limits of the energy contents. When the conditions of the market are not in favor of the wind power, the costs of imbalances can be reduced by making use of the electrical energy storage. Depending on the forecasted errors, the size of the storage would be determined. Dynamic storage sizing has been obtained to be the best method for introducing the wind power energy into the electricity markets (Pinson et al 1-7). Conclusion: It can be concluded from the above study that with advanced technologies and measures, the operation and sizing of energy for wind power plants in markets are achieved, considering the need and importance of removing the issues of intermittent supply and the markets. References Blabbjerg, Frede and Zhe Chen. Power Electronics for Modern Wind Turbines (Google eBook). Florida: Morgan & Claypool Publishers, 2006. Coxworth, Ben. “CryoEnergy System uses liquid air to store energy.” Gizmag. Gizmag, 2011. Web. 9 October 2013 < http://www.gizmag.com/liquid-air-energy-storage/18148/>. Harris, Stephen. “The 2011 Energy & Environment Winner - CES.” Theengineer. Theengineer, 2011. Web. 9 October 2013 . Korpas, Magnus, Arne T. Holen and Ragne Hildrum. “Operation and Sizing of Energy Storage for Wind Power Plants in a Market.” International Journal of Electrical Power & Energy Systems, 25.8, 599-606. Korpas, Magnus, Ragne Hildrum and Arne T. Holen. “Operation and Sizing of Energy Storage for Wind Power Plants in a Market.” PSCC. PSCC, 2002. Web. 8 October 2013 . Lo, Chris. “Reliable renewables with cryogenic energy storage.” Power-technology. Power-technology, 2013. Web. 8 October 2013 . Pielke, R.A. Climate Vulnerability, Volume 3. Oxford: Newnes, 2013. Pinson, Pierre et al. “Dynamic Sizing of Energy Storage for Hedging Wind Power Forecast Uncertainty.” Pierrepinson. Pierrepinson, n.d. Web. 10 October 2013 . Pistoia, Gianfranco. Electric and Hybrid Vehicles: Power Sources, Models, Sustainability, Infrastructure and the Market (Google eBook). Netherlands: Elsevier, 2010. Richard, Michael Graham. “More Pumped Hydro Storage Could Help Wind & Solar Power.” Treehugger. Treehugger, 2010. Web. 9 October 2013 . “UK university to set up new Centre for Cryogenic Energy Storage.” CIIEN. CIIEN, 2013. Web. 9 October 2013 . “Wind Electricity Generation.” Practicalaction. Practicalaction, n.d. Web. 8 October 2013 . Read More