Recommendations For Efficient Energy Storage For Solar-PV And Wind Turbine Systems
Energy Storage for Renewable Energy Sources
Energy storage is the capture of energy generated at one time for use at a later time. This energy exists in so many forms; radiation energy, potential energy, electricity energy, gravitational energy, latent heat energy, kinetic energy and chemical energy (Boyle, 2014, p. 56).
Notable examples of these energy storage systems are rechargeable batteries which basically stores chemical energy that can be readily transformed into electrical energy and can be used to charge mobile phones, operate a vehicle, and operate a radio, among other uses. Another one is hydroelectric dams which stores energy in a big reservoir in the form of gravitational potential energy. So far this is the largest source and mode of energy storage worldwide (Dincer, 2014, p. 78).
The reason why there is a need for these energy storage systems is the unreliability and the unpredictability of energy supply from these renewable sources of energy.
Production might be so low on a rainy or a windless day yet the demand from the power grid remains constant or might even rise sharply (Field, 2014, p. 76). This calls for a storage system to maximize on maximum production when the conditions favor production. The modern energy storage systems, otherwise abbreviated as ESS, provide such a mode of storage of energy for later use. (Dincer, 2015, p. 132)
These energy storage systems have both their positive aspects and the negative aspects as or rather pros and cons as we shall discuss below.
Positive and negative aspects of the energy storage systems
Encourages proper utilization of intermittent renewable energy sources- energy production from these renewable sources of energy is so variable. They can stop unexpectedly, something that would affect production thus not satisfying the demand. For this reason, energy storage systems offer a solution by providing a medium through which energy can be produced to its maximum quantity when the conditions favors production and then be kept for later use when the conditions are poor and production dwindles (Herberg, 2013, p. 68).
They can be put together to form an integrated system of energy- energy storage systems, for example the electric vehicles, can form an integrated system of energy supply to which can serve for more hours and support a variety of appliances (Dincer, 2014, p. 89).
Curtails the necessity for an increased generation during the high demand hours- this is because during such high demand moments, the production from the source could have gone down due to unfavorable conditions. So high production can be done during favorable conditions and then stored for use when production can’t meet demand (Hibbs, 2013, p. 78).
Positive and Negative Aspects of Energy Storage Systems
Boosts grid reliability- they ensure that energy is always available when required and that the constant outages are done away with. In this manner they make the energy sources reliable.
They have continued to record an improvement in not only performance but also the cost- over the time of their continued usage, the energy storage systems have improved greatly both in their performance and also in their costs. This provides optimism of their greater reliability and dependency in the future (Kalhammer, 2014, p. 89).
Energy storage systems makes it possible for the renewable energy sources and the fossil fuels to integrate- nowadays, the renewable sources of energy and the traditional fossil fuels can be harnessed together to produce better outcome.
- There is loss of energy in the inefficiency caused by what we call ‘round trip’- round trip efficiency is the ratio of the energy stored in energy storage systems to the energy that is eventually retrieved from such a system expressed as a percentage. The higher the percentage the higher the round trip efficiency. The inefficiency comes in when some energy leaks out during such storage and retrieval cycles. All of these storage systems have such inefficiencies at a varying rate(Rydh, 2014, p. 90).
- Energy storage systems have extra cost in putting them up and are also complex in nature-owing to their complexities, these energy storage systems involve a lot of costs in erecting them up, running them and also maintenance costs. An example is the electric vehicles which forms an integrated system, and requires very high costs(Thomas, 2016, p. 98)
- Extra infrastructure and space necessities-erecting such complex systems of energy storage requires a good infrastructural outlay which takes plenty of space also.
All in all, the pros outweigh the cons so it is something worth investing to help deal with constant deficiency of energy when the demand goes up and the supply cannot sustain it (Rufer, 2013, p. 165).
Commercial availabilities of energy storage systems which could be used to support some of the renewable energy applications.
Below are some of the energy storage systems, other than batteries, which can be used to support the renewable energy application;
The world is slowly moving from the constant use of fossil fuels which are getting depleted day by day. These fossil fuels used to perform two functions in one, in that they were both the sources of energy and also the storage systems for that energy produced (Field, 2014, p. 154).
In contrast, the new renewable sources of energy would be looked at separately in terms of production and storage. Their ability to enable us to store this energy produced when its production quantity exceeds what is being demanded by the users will be a vital area of concern so that we can get the best out of them (Luo, 2014, p. 85).
This is because energy production and supply from these renewable sources such as wind, solar, tidal, geothermal among others are so unpredictable in that they start and stop at irregular intervals and it necessitates storage to mitigate such and ensure that it so conserved when it is available in large amounts and it is not needed so that to be used when it is not available and it is needed (Lund, 2016, p. 145).
The main thing here is to go on accumulating the energy by harvesting it at a constant rate, not paying attention to its demand which might rise and fall but not in accordance with its production. The excess production over demand is directed to storage forms which may take the forms of electric batteries (charged), flywheels, electrolytic production, pumped water or even heat. (Herberg, 2013, p. 165)
Methods of Energy Storage
Apparently, the first main modern way of energy storage has been pumped storage hydro. In this invention, the excess energy produced is harnessed in pumping the water uphill into an artificial storage which then will be added back into the normal flow to help in the production of more energy during the times when demand becomes so high. Such a method is among the most efficient means of energy storage which actually makes up about 75% of the methods used, though it has a demerit of not being readily available (Rufer, 2013, p. 143).
Another storage means is hydrogen storage. Through this method, the extra electricity produced is harnessed to produce hydrogen and oxygen from water through the process called electrolysis. This energy can then again be gotten back by running the hydrogen and oxygen into a fuel cell or we can also use direct combustion of the two gases, that is, hydrogen-oxygen, to run gas turbines (Field, 2014, p. 178).
Another storage means is through compressed air whereby a device known as a motor compressor is used to pump air up a tank. The air would then get reversed when the energy is on demand whereby it would turn the motor into an electric generator while the compressor would act as a turbine. During this process a lot of heat is produced. Due to this, there has been a new development whereby a device which harnesses this heat is utilized for other uses. The device was developed Light sail energy. It has helped in improving the turbines effectiveness for up to 70% (Kalhammer, 2014, p. 198).
Another storage means, the flywheel, stores its extra energy produced in a spinning motor which as a result of its tendency to always resist motion, usually maintain constant rotation speed. They are applied in vacuum enclosures to do away with the friction which is caused by air, giving them renewed efficiencies. Such systems may be used in the maintain ace of regulated frequencies in the typical fossil fuel plants, which replaces the need to have more fossil plants (Rufer, 2013, p. 164).
Another means is storage through thermal energy storage. This one stores the energy in a storage medium at a certain regulated temperature which will later be used when need arises such as the times of high demand. The storage takes form of hot water, molten salts or heated gravels. Some firms have resorted to using the excess energy produced in the creation of ice which is stored and later used in the provision of air conditioning services during the summer seasons in huge buildings, both commercial and residential. During the night hours, electricity is not only cheaper but also contains a bigger component of wind power which makes it purer or clean.in the United States, the storage through thermal is the second most preferred means after pump storage, and its use is projected to grow in the near future owing to the continued growth in solar energy (Herberg, 2013, p. 167).
Pumped Storage Hydro
Storage through electric vehicles can’t be left out either since in doing so we would be missing out on bigger things. Electric vehicles energy storage acts as a collective entity and forms the biggest component in the energy storage system. When the windmills are at work at night, with the electric vehicles, otherwise abbreviated as EVs, parked in the garages, can use their batteries to siphon the clean output which is often carbon free, and at the same time making for the once exclusive component of gasoline (Holtom, 2015, p. 154).
When it comes to daytime, these electric vehicles are connected to smart charging stations which facilitates charging and discharging that usually becomes the hallmark of an integrated channel that are interconnected using smart networks. This smart technology has been witnessed in japan in a program they call ‘Japan’s smart cities program’. Since this type of energy storage uses carbon, it has been projected that it could help curtail the carbon dioxide in the atmosphere by close to 9,000,000,000 tons by the year 2020 (Hibbs, 2013, p. 166).
Impacts on the environment during the usage of these energy storage systems and the wastes produced from some of these systems
The environmental impacts of the usage of these energy storage systems can be both positive and negative. Some of the impacts are discussed below;
Positive impacts:
- Climate change – the continued use of the renewable sources of energy such as the solar energy and windmills have greatly helped in taming the menace of global warming that was caused by the continued use of sources such as coal. Coal used to emit a lot of carbon into the atmosphere and such emissions of carbon into the atmosphere destroyed the ozone layer, which is the protective layer that shields the earth from the strong heat from the sun(Osman, 2015, p. 121). This heat often resulted into global warming. Most countries have embraced the use of these renewable clean sources of energy in their quest to decarbonize the world and establishment of clean cities. The use of these energy storage systems have thus helped in carbon mitigation, a gas which is highly toxic to the health of human beings (Cho, 2016, p. 139).
- The use of the energy storage systems has helped in curbing the depletion of fossil fuel which was constantly being used. They have provided an alternative and thus have given a breather to the use and constant search for fossil fuel(Cho, 2016, p. 154).
These energy storage systems have provided indirect benefits to the environment such as; integration of the more renewable energy into electricity grid, they have helped the generation plants operate at their most efficient levels (Copeland, 2014, p. 146).
Large scale use of these energy storage systems have reduced pollution to the environment such as fresh water Eco toxicity, emission of greenhouse gases, eutrophication and production of the particulate matters.
NEGATIVE IMPACTS:
- Effects on the environment
The lithium and lead which are the main raw materials used in the production of batteries gets disposed at the end of their life cycles. Such disposal poses health hazards to human beings if not done in the right manner or if not recycled. Lithium and lead are very poisonous substances and requires a lot of caution when being handled (Field, 2014, p. 216).The latter can lead to the environmental degradation and ugliness of the vicinity.
- Disturbance of plants
There is also the problem of the particulate matter production which can affect human health. Most plants are putting necessary measures though to help mitigate such.
- Costs in environmental maintenance
Leads to additional costs in the environmental maintenance the disposed waste products lead to the pollution and this leads to added expense in the efforts to maintain the environment clean and also leads to increase in the social costs.
Hydrogen Storage
Recommendations for efficient energy storage for solar-pv and wind turbine systems.
Heat based energy storage system is mostly favored in thermal solar plants that uses the technology of heat concentration using the mirror arrays instead of relying on the common photovoltaic panels (D’Errico, 2013, p. 212). The concentrated sunlight raises the temperature of a high-heat holding substance, for example molten salt. This stored heat is used to turn water into vapor that is used to which drives a steam turbine. So the availability of enough energy just depends on the amount of heat stored from the concentration process (Holtom, 2015, p. 213).
One ought to introduce the off-lattice frameworks at homes since they come up short on a primary power supply and utilize a diesel generator.
- Utilize reinforcement, lattice associated frameworks
These ought to be introduced to in light of the fact that they are huge in spots where the issue of intensity cuts is normal or basic like doctor’s facilities. These reinforcements switch on consequently when there is control cut.
- Utilizing framework associated frameworks
On account of a framework associated wind turbine or PV nearby planetary group, the batteries don’t have to store power for quite a while. This battery shuts the hole between generation of power and the requirement for power. Henceforth this prompts decrease of power sold and obtained back later.
The use of the third one, that is the hydrogen fuel cells, is based on electrolysis and is perhaps the most complicated of the above mentioned. In this method, water is separated into hydrogen and oxygen. The hydrogen produced is stored and later used to power fuel cell which again does the previous process of combining the hydrogen and the oxygen thus providing electricity. Due to this complicated and expensive process, there should be a reduction in the amount of electricity which is required in the production of goods for export. (Rufer, 2013, p. 187).
Future developments in the field of energy storage systems as a way of further sustainable developments
- The energy storage systems mentioned above can only store the energy for few hours or minutes. There is thus the need to come up with new developments that will increase the energy holding capacity and duration. The energy storage systems are a very vital area as the world seeks to move away from the use of non-renewable sources to renewable sources and also to decarbonize the world(Herberg, 2013, p. 193).
- The future is bright as researchers are working round the clock to make sure that we get new developments and improvements from the current storage systems that we have.
One such areas of developments are the flow batteries. These special types of batteries use chemicals dissolved in water unlike the previous ones which uses lithium ion. The flow batteries last longer than their predecessors (Dincer, 2014, p. 56). They thus can be used longer. They can store enough energy to counter the increased demand at the peak hours when the consumers use a lot of it. They are also known as redox flow batteries (Thomas, 2016, p. 243).
- Another upcoming and first rising development are the super capacitors. In the normal lithium ion batteries, there is the problem of energy lose during charging and discharging, short life cycle, slow charging ability and other limitations(Boyle, 2014, p. 267). The super capacitors will help overcome these limitations since they offer faster charging capacity and life time that is almost twice the period taken by the lithium ion batteries. They also store huge capacity of the energy (Herberg, 2013, p. 235).
- The final development is the superconducting magnetic energy storage. These ones enable current to continue flowing even after the removal of the voltage across it. Its energy is stored in the form of magnetic field that comes from the current in the superconducting coils. Their efficiencies are as high as we just to convert the AC to DC. It can be used to store and discharge huge amounts of energy(Field, 2014, p. 178).
Conclusion
ESS are used as storage systems for the harvesting and storage of electric power. The application of the energy system determines the kind of energy system that needs to be utilized.it is always important o store energy during the times when demand is low so that we take care of the future shortages and unseen risks in general. The renewable sources on the other hand should keep doubling their efforts so as to optimize on the scarce resources. The latter includes the application of solar systems in the production of electricity among other storage systems. Research should keep on going on the different methods that need to store energy.
References
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