Two is sometimes preferable to one. One such instance is the fusion of solar power with storage technologies.The reason for this is that solar energy isn’t always available when it’s needed. Peak electricity use typically occurs in the summer afternoons and nights, when solar energy generation is at its lowest. The temperature may be at its peak when individuals who work during the daytime return home, and they begin using electricity to cool their homes, cook, and use appliances.
Even when the sun isn’t shining, storage enables solar to contribute to the supply of electricity. Additionally, it can aid in reducing fluctuations in the grid’s transmission of solar energy. Photovoltaic (PV) panels or concentrating solar-thermal power (CSP) systems experience variations in the amount of sunshine that strikes them. Season, time of day, clouds, dust, haze, or impediments like shadows, rain, snow, and dirt can all have an impact on how much solar energy is produced. In either form, energy storage can assist more successfully integrate solar into the electricity grid. Sometimes energy storage is co-located with or positioned close to a solar energy system, while other times the storage system stands alone.
Energy Storage: What Is It?
Technologies that can catch electricity, convert it into another type of energy (chemical, thermal, or mechanical), store it, and then release it when needed are referred to as “storage.” One such technology is lithium-ion batteries. Energy storage enables flexible energy use at periods other than when it was generated, even though it is never 100% efficient because energy is always lost in the conversion and retrieval processes.Thus, by balancing supply and demand as well as system resilience and efficiency, storage can enhance power quality.
Energy capacity, which is the total quantity of energy that can be stored (often in kilowatt-hours or megawatt-hours), and power capacity, which is the amount of energy that can be discharged at a specific time, are two different factors for storage facilities (usually in kilowatts or megawatts). Various energy and power storage capacities can be used to handle various jobs. While longer-term storage can help provide supply over days or weeks when solar energy production is low or during a significant weather event, for example, short-term storage that lasts only a few minutes helps ensure a solar plant functions smoothly throughout output changes caused by passing clouds.
Benefits of Combining Solar and Storage
- Electricity load balancing – Without storage, electricity must be produced and consumed simultaneously, which may require grid operators to “curtail” some production in order to prevent overproduction and grid dependability difficulties. On the other hand, there may be times when there is minimal solar production but a lot of demand for electricity, such as after sunset or on cloudy days. Here comes storage, which can be topped off or charged while power consumption is low and generation is high, then used up when load or demand is high. When a portion of the solar energy generated is stored, it can be used anytime grid operators require it, even after the sun has set. Storage serves as a sort of solar insurance in this way.
- “Firming” solar energy production A solar power plant’s output can be kept from being significantly impacted by sudden fluctuations in generation with the help of short-term storage. To maintain a “firm” electrical supply that is dependable and consistent, the grid can employ a tiny battery, for instance, to ride through a brief generating disruption caused by a passing cloud.
- Resilience – In the event of an electricity outage, backup power can be provided via solar and storage. They are able to maintain vital infrastructure in order to maintain crucial services like communications. Microgrids and smaller-scale applications like mobile or portable power units can also use solar energy and storage.
Energy Storage Types
Pumped hydropower is the most prevalent kind of energy storage in the electrical system. However, thermal storage (fluids) and electrochemical storage (batteries) are the storage technologies that are most typically paired with solar power facilities. Other forms of storage, including flywheels and compressed air storage, may have unique qualities that appeal to grid operators, like extremely quick discharge or very big capacity. Below is further information about various storage options.
Hydropower with Pumped Storage
A water-based energy storage method is pumped-storage hydropower. When there is little need for energy, water is pumped uphill into a reservoir using electrical energy. When demand for energy is great, the water can be permitted to run back downhill and turn a turbine. Since 1929, the United States has used pumped hydro, a proven and sophisticated storage technology. However, it necessitates proper landscapes and reservoirs, which may be man-made through the construction of dams or created naturally by the construction of lakes, and it costs a lot of money up front and takes a long time to implement. In addition to energy arbitrage, the value of services provided by pumped hydro to integrate variable renewables is not completely appreciated, which might prolong the financial payback period. These are some of the reasons why pumped hydro hasn’t been built recently, despite the fact that the Federal Energy Regulatory Commission has received requests for preliminary permits and licenses indicating interest.
Electrical Energy Storage
Electrochemical batteries, such as those used in laptops and mobile phones, are well known to many of us. A battery stores energy when electricity is put into it, which triggers a chemical reaction. When a battery is depleted, this chemical process is turned around, resulting in voltage between two electrical contacts and current flowing out of the battery. Lithium-ion is the most used battery chemistry, but lead-acid, sodium, and nickel-based batteries are also widely used.
Storing Thermal Energy
The term “thermal energy storage” refers to a group of technologies that use a fluid, such as liquid water or molten salt, or another substance to store heat. The energy is then kept in an insulated tank using this thermal storage material. The energy can either be used to produce electricity or used directly for heating and cooling. The heat is utilized to boil water in thermal energy storage devices designed for electrical use. Using the same machinery found in conventional electricity producing facilities, the generated steam powers a turbine to provide electrical power. CSP plants, which concentrate sunlight onto a receiver to heat a working fluid, can benefit from thermal energy storage. As a working fluid that could benefit from greater temperatures and lower the size of producing facilities, supercritical carbon dioxide is being investigated.
Storage for flywheels
A hefty wheel linked to a revolving shaft is called a flywheel. The wheel can rotate more quickly by using more energy. By coupling the wheel to an electrical generator that employs electromagnetism to slow the wheel down and generate electricity, this energy can be captured. Flywheels can deliver power quickly, but they have little energy storage.
Keeping Compressed Air
Large vessels, like tanks, or natural formations, like caverns, are used as compressed air storage systems. The pressured air is pumped into the containers using a compressor system. The air can then be let out and used to turn an electricity-generating turbine. The released air from existing compressed air energy storage devices is frequently used to generate electricity as part of a natural gas power cycle.
New fuels that may be burned or consumed to provide energy can be made using solar electricity, effectively storing the solar energy in the chemical bonds. Hydrogen, created by removing oxygen from water, and methane, formed by mixing hydrogen and carbon dioxide, are two potential fuels that researchers are looking into. Natural gas, which is frequently used to generate power or heat homes, primarily consists of methane.
By altering the way we utilize the gadgets we already have, energy can also be preserved. For instance, a building can “store” thermal energy so it won’t need to use power later in the day by heating or cooling the building before a predicted peak in electrical demand. By holding either warm or chilly air, the structure itself serves as a thermos. To spread out demand throughout the day, a similar procedure can be used with water heaters.
In the end, solar-plus-storage systems can be advantageous for both residential and commercial solar consumers, utilities, and large-scale solar operators. Solar and storage technologies will become more affordable for all Americans as research advances and their costs decline.