Con el objetivo de cambiar esta frustrante situación, Siemens está desarrollando en colaboración con la Universidad de Tecnología de Hamburgo y la compañía energética local, Hamburg Energie, un nuevo sistema de almacenamiento, denominado Future Energy Solution (FES) capaz de almacenar el exceso de energía generado por parques eólicos durante varias horas, o incluso durante un día entero. Esta solución se integra, además, en el proyecto Sistemas Energéticos del Futuro, creado por el Ministro de Economía alemán, con el fin de ayudar a resolver el problema de cómo almacenar de forma asequible la energía generada por aerogeneradores cuando no sea necesaria, o no pueda ser transmitida por sobrecargas de potencia. Sencilla técnica de almacenamiento con piedras naturales Esta tecnología ya se está probando en Hamburgo en una fábrica a pequeña escala; que es la esencia de la simplicidad técnica. En primer lugar, esta planta convierte el exceso de energía en calor, que es soplado hacia un compartimento aislado con piedras en su interior. Estas rocas se calientan hasta alcanzar una temperatura superior 600 ºC. Si hay un aumento de la demanda de energía, las rocas calientan un flujo de aire que se conduce a un ciclo de vapor para generar electricidad. Este sencillo diseño utiliza piedras naturales, es rentable y puede ser usado potencialmente como un complemento a los sistemas de almacenamiento ya existentes. Setting out to change this frustrating picture, Siemens, in collaboration with the Hamburg University of Technology and municipal utility company Hamburg Energie, is developing a new energy storage system Future Energy Solution (FES). This system is able to store the excess power generated by wind farms for several hours or even a whole day as part of the Future Energy Systems project, funded by Germany’s Ministry for Economic Affairs. The project aims to solve the problem of how the energy generated by wind turbines can be affordably stored when it is not needed or cannot be transmitted because of potential overloads. Simple storage technique using natural stones This technology is already being tested in Hamburg in a small prototype facility and is the essence of technical simplicity. It converts surplus energy into heat, which is blown into an insulated, inner bin filled with stones. The rocks heat up to temperatures of more than 600ºC. If there is an increase in the energy demand, the rocks heat an airflow that drives a steam cycle to generate electricity. This straightforward design uses natural stones, is cost-effective and could potentially be used to supplement existing storage systems. By developing this new system, Siemens Corporate Technology is playing an important role in optimising the overall concept of the FES. Since 2016, the company been running a test facility at the Siemens campus in Erlangen, where experts are currently examining how heat is transported inside containers filled with stones. It is very important to understand the heat transport phenomenon inside the storage system in order to increase its overall efficiency and build a full-scale power station. Simplified measurements The prototype Hamburg facility is located in a container approximately 5 metres long. Instead of stones, it contains around 13,000 ceramic balls. The advantage of using ceramic balls is that they all have the same size and shape, which makes it easier to calculate the heat transport process inside the bin. However, ceramic balls can only be used during the test phase. The next step is to fill the storage system with natural stones to study how irregular shapes and a variety of materials influence heat transport. Ceramic balls cannot be used in a large-scale facility because they would be too expensive. Researchers ALMACENAR EL EXCESO DE ENERGÍA EÓLICA EN PIEDRAS NATURALES Y CONVERTIR EL CALOR EN ELECTRICIDAD Uno de los grandes problemas de la energía renovable es la dificultad de almacenar el exceso de energía y ver cómo se desaprovechanmiles de megavatios que no pueden ser reutilizados. Es lo que sucedió hace pocos meses en Alemania, cuando una tormenta con una zona de bajas presiones, llamada Theresa, pudo ser capaz de generar más de 31.000 MW de electricidad para la red alemana; una cantidad enorme de energía comparada con un día normal. Sin embargo, esta cantidad ingente de energía no se pudo aprovechar en su totalidad debido a la falta de sistemas de almacenamiento eficientes y asequibles. STORING SURPLUS WIND POWER IN NATURAL STONES AND CONVERTING HEAT INTO ELECTRICITY One of the main issues with renewable energy is the problem of storing excess power and seeing how thousands of megawatts that cannot be reutilised are wasted. This is what happened a few months ago in Germany, when a low-pressure zone called Theresa caused more than 31,000 MW of wind power to be fed into the country’s grid – a tremendous surge of power compared to an average day. However much of this energy was never fully utilised because of the absence of efficient and affordable storage systems. FuturEnergy | Junio June 2017 www.futurenergyweb.es 31 Eólica | Wind Power
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