About Solar Energy : Solar Energy Definition
What are the types of solar energy storage methods and the different battery types that can store this energy.
In this article we focus on the definition of solar energy and the technologies used to generate it.
Solar energy generates renewable or "green" power by harnessing the sun's light and heat.
Solar panels, also known as photovoltaic cells, are the most common way to harness solar energy.
They're almost edge-to-edge in Solar Power plants to capture sunlight in wide fields.
You'll occasionally find them on top of buildings.
Semiconductor materials are used to make the cells.
The sun's rays free electrons from their atoms when they strike the cells.
This permits electrons to flow freely across the cell, resulting in the generation of electricity.
Solar collectors can produce electricity for thousands of individuals at once on a much wider scale.
Solar-thermal power plants employ a variety of methods to generate electricity from the sun.
The sun's energy is utilized to boil water, which then powers a steam turbine, which generates electricity similar to coal or nuclear power stations.
Solar energy may be harnessed using three different technologies:
Photovoltaics (PV), which convert light directly into electricity.
Concentrating Solar Power (CSP), which uses solar thermal energy to power large-scale electric turbines.
Solar heating and cooling (SHC) systems that collect thermal energy and use it to heat or cool water and air.
Photovoltaics (PV) solar energy frees electrons in these materials, which can then be induced to move through an electrical circuit, operating devices, or transmitting electricity to the grid.
PV gadgets can be utilized to power everything from calculators to road signs, as well as households and huge commercial companies.
How does photovoltaic (PV) technology work?
Photons ionize the semiconductor material on the solar panel, causing outside electrons to break their atomic bonds.
The electrons are driven in one direction by the semiconductor structure, resulting in an electrical current flow.
Solar cells made of crystalline silicon are not 100% efficient, in part because only specific wavelengths of light can be absorbed.
Some of the light spectrum gets to be reflected, while others (infrared) are too faint to generate electricity, and still others (ultraviolet) generate heat energy rather than electricity.
Photovoltaic Technology in Other Forms
There are two basic forms of PV technology, in addition to the crystalline silicon (c-Si):
Thin-film PV is a tiny but rapidly expanding segment of the commercial solar business.
Many thin-film companies are startups experimenting with new technologies.
They are less efficient than c-Si modules, although they are often less expensive.
Concentrating PV arrays are mostly found in the desert Southwest of the United States.
They reflect concentrated Solar Power onto high-efficiency cells using lenses and mirrors.
Building-integrated photovoltaics function as the outer layer of the structure and generate power for on-site usage or export to the grid.
They require direct sunshine and tracking devices to be most successful.
BIPV systems can save money on materials and electricity, reduce pollution, and improve a building's esthetic appeal.
Concentrating solar power (CSP)
CSP plants employ mirrors to concentrate the sun's energy, which is then used to power traditional steam turbines or even engines to generate electricity.
A CSP plant's concentrated thermal energy can be stored and utilized to generate electricity whenever it is required, day or night.
In the United States, approximately 1,815 megawatts (MWac) of CSP facilities are currently operational.
Curved mirrors focus the sun's power onto a receiver tube which does operate along the center of the trough in parabolic trough systems.
A high-temperature heat transfer fluid (like synthetic oil) absorbs the sun's energy in the receiver tube, heats water, and produces steam by passing through a heat exchanger at temperatures of 750°F or higher temperatures.
To generate electricity, the steam powers a traditional steam turbine power plant.
Thousands of parallel rows of the troughs linked as a series of loops are positioned on the north-south axis so that the troughs may track the sun from the east direction to the west direction in a typical solar collector field.
Individual collector modules range in elevation from 15-20 feet to 300-450 feet.
Compact Linear Fresnel Reflector
CLFR is based on curved-mirror trough technologies but with lengthy parallel rows of less expensive flat mirrors.
The sun's energy is focused onto raised receivers, which are made up of the structure of tubes via which water flows.
The concentrated sunlight can boil the water, resulting in high-pressure steam that can be used directly in power plants and industrial steam applications.
A central receiver system is used in power tower systems, allowing for higher operative temperatures and consequently higher efficiency.
The sun is tracked along two axes by computer-controlled mirrors (called heliostats), focusing Solar Power on the receiver at the top of a high tower.
The concentrated energy is utilized to heat the transfer fluid to over 1,000 degrees Fahrenheit to generate steam and power a central power generator.
These projects can readily and cost-effectively incorporate energy storage, enabling 24-hour power generation.
A parabolic dish's surface is covered in mirrors, which concentrate sunlight on the receiver fixed at a focal point.
Unlike other CSP technologies that use steam to generate power via the turbine, this dish-engine system drives an engine using a working fluid like hydrogen heated to 1,200° F in the receiver.
To track the sun, each dish spins along two axes.
The Most Important Requirements for the Concentrating Solar Power Plants
Funding - Project financing is the most difficult aspect of any utility-scale energy-producing infrastructure, including CSP.
High-solar-radiation areas - The sun's energy should not be too diffused to focus on it.
A direct normal intensity (DNI) of the sun's energy is used to determine this.
Contiguous tracts of land with little cloud cover - CSP plants with capacities of 100 MW and greater function most efficiently and thus cost-effectively.
While the amount of land required varies depending on the technology, a typical CSP facility requires 5 to 10 acres per MW of capacity.
Thermal energy storage is possible due to the larger land area.
Water resources - Like similar Thermal Power plants like coal, natural gas, and nuclear, most CSP systems require water for cooling.
To clean the collection and mirror surfaces, only a small amount of water is required.
CSP facilities can use wet, dry, and hybrid cooling systems to enhance efficiency in power generation and water conservation.
Transmission access that is both available and close - CSP plants must be built on appropriate terrain for electricity generation and have adequate access to a rapidly overburdened and antiquated transmission grid.
The construction of utility-scale Solar Power facilities requires accessibility to high-utility transmission lines to transport electricity to end consumers from the Solar Power plant.
Much of the Southwest's existing transmission system is at capacity, and new transmission is desperately needed.
SHC (solar heating and cooling) systems are a type of solar heating and cooling system.
Solar heating and cooling (SHC) systems capture the sun's thermal energy and use it to produce hot water, room heating, cooling, and pool heating in residential, commercial, and industrial settings.
Electricity and natural gas are no longer required because of these technologies.
Solar heating and cooling solutions are being manufactured and installed around the world, reducing our reliance on imported fuels dramatically.
To expand this fast-growing, job-creating sector, governments need wise policies.
Solar energy storage
Solar panels have one drawback that even the most enthusiastic solar evangelists can concur on: they only generate power when the sun is shining.
On the other hand, peak energy use occurs in the nights, coinciding with lower solar generation and resulting in a supply and demand problem.
On the other hand, solar panels frequently produce enough energy during low-demand hours when the sun is shining to fulfill peak demand afterwards in the day.
This means that effective solar energy storage can provide a wide range of benefits to both homeowners and businesses.
This article shall cover the benefits of solar energy storage, how it operates, and how it might help.
What Are the Advantages of Solar Energy Storage?
Storing excess energy is critical to extracting the maximum out of the solar panel system.
It can lead to cost savings, more effective energy grids, and lower fossil fuel emissions.
There are several advantages to storing solar energy:
1. Electric load balancing
If electricity isn't stored, it must be consumed immediately after it is generated.
Energy storage enables surplus generation to be stored for peak demand.
When it comes to renewable energy, storing excess power means allowing the lights to be able to stay on even when the sun sets, or the wind halts blowing.
Simply said, energy storage permits an energy reservoir that will be charged when demand is low, and generation is high, then released when demand increases and generation decreases.
2. Filling in the gaps.
Short-term solar energy storage ensures a steady flow of energy during generator outages, like routine maintenance or passing clouds.
3. Energy resilience.
From wildfires to extreme storms, the electrical grid is prone to disturbances and outages.
By decentralizing where we acquire our energy, solar energy storage offers a protective bubble during catastrophic events.
What is the best way to store solar energy?
The storage of solar energy can be categorized into three parts: thermal, battery, and mechanical.
Let's take a look at each one separately.
What is thermal storage?
Thermal energy storage absorbs and retains heat from the sun using a variety of materials, like water or molten salt.
This heated medium is kept in the insulated tank until it's time to use, which is normally to boil water for energy production.
What is battery storage?
Electrochemical batteries can also be used to store solar energy.
When solar energy is injected into a battery, the energy is stored through a chemical process among the battery components.
When the battery is depleted, the reaction is reversed, allowing the current to depart the battery.
Lithium-ion batteries are the most prevalent type of battery utilized in solar applications, as well as new battery technology is fast developing, promising cheaper, additional scalable battery storage solutions.
Indeed, by 2025, annual energy storage in the United Kingdom is predicted to reach almost 7.5 GW, a sixfold increase from 2020, creating a market value of over $7.3 billion.
What is mechanical storage?
To generate electricity, mechanical energy storage uses the prospective energy of an object.
Surplus electrical power is transformed into mechanical power, which then is converted back into power for later use.
Mechanical energy storage devices are divided into three categories:
Flywheel. This approach takes advantage of surplus power to spin the flywheel, which then creates electricity to meet peak demand.
Pumped hydro. Water is pumped upward to a reservoir above turbine generators in pumped hydro.
When there is a significant demand for power, the water is permitted to run through turbines and produce electricity.
Compressed air. Compressed air is injected into huge vessels such as tanks or underground formations with this energy storage technology.
During peak demand, the air is discharged to generate power.
The Most Effective Solar Energy Storage
There is no one-size-fits-all answer to solar energy storage.
Solar energy storage options are dependent on your needs and resources.
Let's take a look at some of the most prevalent solar energy storage alternatives for commercial and residential use.
Commercial Solar Energy Storage
Mechanical and thermal storage are viable solutions for utility corporations and other enterprises with larger budgets than individuals.
Even though these storage systems might be expensive, they assist utilities in meeting peak energy demand.
Grid energy storage featuring next-generation batteries. In the United States, 2020 was a milestone year for new power storage.
The nation installed 476 MW of additional storage in the 3rd quarter alone, up 240% from the previous quarter's record-breaking total.
Although the majority of the new deployments are 1-hour front-of-the-meter (FTM) storage systems, they provide a promising glimpse into the future of commercial solar energy storage.
Compressed air. According to the most recent government estimates, compressed air costs $105 per kWh, rendering it the most cost-effective mechanical storage alternative for large-scale applications.
Pumped hydro. The solar energy that isn't consumed could be utilized to pump water upwards, generating a huge quantity of potential energy.
Pumped hydro costs roughly $165/kWh right now, leaving it the second-best option for large-scale mechanical energy storage.
However, because new pumped hydro involves substantial upfront costs and considerable regulatory hurdles, it is only viable in specific places.
Home Solar Energy Storage
Cost savings, resiliency, and decentralization of electricity output (sometimes known as "virtual power plants") are just a few of the advantages of residential solar.
However, the commercial energy storage solutions we outlined above are likely prohibitively expensive for the average homeowner.
Battery storage, thankfully, can now provide households with a cost-effective and reliable solution to store solar energy.
Lithium-ion batteries are by far the most popular choice for storing solar energy at home.
They're inexpensive (and getting cheaper), have a low profile, and may be used for a variety of purposes.
Saltwater batteries and lead-acid batteries are two more types of batteries often used in homes.
Regardless of battery type, home backup batteries allow homeowners to preserve energy during periods of high production and low demand (e.g., throughout the workday) for usage during periods of high demand when generation drops.
Home solar energy storage benefits are similar to those of large-scale solar energy storage, resulting in resiliency, uninterrupted electricity, and cost savings.
These advantages are passed on to the homeowner.
So, how exactly do batteries function?
Batteries are the device which converts chemical energy to electric energy.
They are made up of two electrodes, an anode, and a cathode, which is formed of conductive materials and separated by a separator.
The electrolyte, a chemical substance comprising ions, sits between the anode and the cathode, reacting with the conductive elements of the cathode and anode to produce an electric current.
Chemical redox (oxidation-reduction) reactions in the electrodes cause ions to travel between the two electrodes and electrons to be released from one electrode.
Free electrons collect at one electrode, leading to differing charges that the electrons will try to balance by moving to the other electrode.
The separator, on the other hand, stops them from moving, effectively breaking the electric circuit.
The electrons can move between the electrodes after the circuit is formed (both the anode and the cathode are linked), and the battery is effectively depleted.
Various types of batteries
Batteries come in a variety of chemical characteristics, life cycles, energy density, operating temperatures, and power density parameters.
The following are the most common battery technologies:
Nickel-Metal Hydride (NiMH)
Carbon-Zinc f) Zinc-Bromine
Solar Energy Definition Summary
As more people switch to renewable and green energy, it's crucial to understand the benefits and drawbacks of each.
Before switching to a modern, greener energy source, attempt to come up with a budget that you and your family can afford.
Then figure out how much the solar energy choice will cost you in the long term and how much you would save.
Make a list of advantages and disadvantages that are special to you and the family so that you may better understand which solutions are more helpful to you than others.