SOLAR ENERGYPresented By-

Abdul HaiB.Sc.A.H.(Hons.)

Level-3,Semester-2Bangladesh Agricultural University , Mymensingh.

SOLAR ENERGY

Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating,

photovoltaics, solar thermal energy, solar architecture, molten salt power plants and

artificial photosynthesis.[1][2]

It is an important source of renewable energy and its technologies are broadly characterized as either

passive solar or active solar depending on how they capture and distribute solar energy or convert it into

solar power.

Solar energy is any type of energy generated by the sun.

TYPES OF SOLAR ENERGY

• Photovoltaic and - Photovoltaic technology directly converts sunlight into electricity.

• Thermal -Solar thermal technology harnesses its heat. These different technologies both tap the Sun’s energy, locally and in large-scale solar farms.

Two different types of installations are used:• Individual systems for homes or small communities. Photovoltaic panels can power electrical

devices, while solar thermal collectors can heat homes or hot water.• Photovoltaic or concentrated solar power plants that cover hundreds of acres produce

electricity on a large scale, which can be fed into power grids.

HOW SOLAR ENERGY ENTERS TO THE EARTH

Almost all of the Earth's energy input comes from the sun. Not all of the sunlight that strikes the top of

the atmosphere is converted into energy at the surface of the Earth. The Solar energy to the

Earth refers to this energy that hits the surface of the Earth itself. The amount of energy that reaches the the Earth gives a useful understanding of the

energy for the Earth as a system. This energy goes towards weather, keeping the

temperature of the Earth at a good level for life and powers the entire biosphere. Additionally, this

solar energy can be used for solar power either with solar thermal power plants or photovoltaic cells.

SOLAR ENERGY TO THE EARTH

Energy from Sun to Earth

The Sun is generally considered to produce a constant amount of power

with a surface intensity of , expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes

less and less intense as an inverse square law.[1] The average radiation intensity that hits the edge of the Earth's atmosphere is known as the solar constant, or . Although this value is called a constant it varies by about 7% between January 4th (perihelion),

when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.[2] Therefore a yearly average is used

and is determined to be .[1] To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total

solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a

sphere that has a radius equal to the distance from the Earth to the Sun.

HOW IS SOLAR ENERGY STORED

• One of the drawbacks of solar energy systems is that the Sun doesn't provide a constant stream of energy.On cloudy days or at night, the amount of energy your system receives is reduced or eliminated altogether. This in turn impacts the amount of electricity or heat that your system produces during those times.• To overcome this drawback, homeowners can take advantage of

several methods available to them for storing solar energy. The methods available differ depending on whether you are using solar electricity applications or solar heating application.

SOLAR ELECTRICITY STORAGE

Homeowners are able to generate solar electricity by using a photovoltaic solar power system. There are two primary methods of Energy Storage with a PV solar power system... Battery Banks Grid Inter-TieOne way solar power storage can be accomplished is by using a battery bank to store the electricity generated by the PV solar power system. A battery solar power storage system is used in a grid-tied PV system with battery backup and stand-alone PV systems

THE MAJOR COMPONENTS OF A BATTERY SOLAR POWER SYSTEM ARE-

• Charge Controller: Prevents the battery bank from overcharging by interrupting the flow of electricity from the PV panels when the battery bank is full.

• Battery Bank: A group of batteries wired together. The batteries are similar to car batteries, but designed specifically to endure the type of charging and discharging they'll need to handle in a solar power system.

• System Meter: Measures and displays your solar PV systems performance and status.• Main DC Disconnect: A DC rated breaker between the batteries and the inverter. Allows the inverter to be quickly

disconnected from the battery bank for service.• The third type of PV solar power system is a grid-tied PV system. This system can actually use the grid as its solar

energy storage system. This is done using net-metering.• With net-metering, when you produce excess solar electricity, you send it to the grid and your electric meter rolls

backwards. Later on, at night for example, when your system is not producing electricity, you can pull electricity from the grid and your electric meter will roll forward. You are essentially using the grid to store your solar electricity!

THE MAJOR COMPONENTS OF A BATTERY SOLAR POWER SYSTEM ARE-

• The third type of PV solar power system is a grid-tied PV system. This system can actually use the grid as its solar energy storage system. This is done using net-metering.• With net-metering, when you produce excess solar electricity,

you send it to the grid and your electric meter rolls backwards. Later on, at night for example, when your system is not producing electricity, you can pull electricity from the grid and your electric meter will roll forward. You are essentially using the grid to store your solar electricity!

STORING PHOTOVOLTAIC ENERGY

Solar panels can not produce energy at night or during cloudy periods. But rechargeable batteries can store electricity: the

photovoltaic panels charge the battery during the day, and this power can be drawn upon in the evening.

Residential systems usually use deep-cycle batteries that last for about ten years and can repeatedly charge and discharge

about 80 percent of their capacity. While batteries can be expensive, in remote areas it can often

be more cost effective to use batteries rather than extending an electricity cable to the grid.

But if choosing to go off the grid in this way, the batteries must be sized correctly, with a storage capacity sufficient to meet electricity needs.

In most cases, though, purchasing electricity from the grid is cheaper than opting for batteries.

SOLAR THERMAL ENERGY STORAGE

Residential solar hot water systems – which use the sun’s thermal energy to heat water for the home – have a simpler

storage system. Water flows through solar collectors on the roof, and then goes to a storage tank where it can be drawn upon as

needed.• Concentrating solar power(CSP) plants use thermal energy to

power a generator. While some CSP facilities use water as the heat transfer medium, most new systems us oil or molten salt. These fluids allow the heat energy to be stored for use during

cloudy periods or at night.Parabolic troughs at the Plataforma Solar de Almeria CSP facility in

Spain. Photo Credit: PSA.es

The solar resource is enormous. Just 18 days of sunshine on Earth contains the same amount of

energy as is stored in all of the planet's reserves of coal, oil, and natural gas.

SOLAR POWER PLANT

• Solar power plant is based on the conversion of sunlight into electricity, either directly using photovoltaics (PV), or

indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors

and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics converts light into electric

current using the photoelectric effect.[1] The largest photovoltaic power plant in the world is the 250 MW Agua

Caliente Solar Project in Arizona.[2]

Concentrated solar power plants first appeared in the 1980s. Now, the 354 MW Solar Energy Generating Systems (SEGS) CSP

installation is the largest solar power plant in the world; it is located in the Mojave Desert, California. Other large CSP plants

include the Solnova Solar Power Station (150 MW, 250 MW when finished)[3] and the Andasol solar power station (150 MW), both in

Spain.[4]Solar power is increasingly used.[5][6] @Murich Airport.

 NUCLEAR POWER PLANT

A nuclear power plant is a type of power station that generates electricity using heat from nuclear reactions. These reactions take place within a reactor. The plant also has machines which remove heat from

the reactor to operate a steam turbine and generator to make electricity. Electricity made by nuclear power plants is called nuclear power.

Nuclear power plants are usually near water to remove the heat the reactor makes. Some nuclear power plants use cooling towers to do this.

Nuclear power plants use uranium as fuel. When the reactor is on, uranium atoms inside the reactor split into two smaller atoms. When

uranium atoms split, they give off a large amount of heat. This splitting of atoms is called fission.

The most popular atoms to fission are uranium and plutonium. Those atoms are slightly radioactive. The atoms produced when fuel atoms break apart are strongly radioactive. Today, fission only happens in nuclear reactors. In nuclear reactors, fission only happens when the reactors parts are arranged properly. Nuclear power plants turn their

reactors off when replacing old nuclear fuel with new fuel.There are about four hundred nuclear power plants in the world, with many

in the United States, France, and Japan.

CONVERTING SOLAR ENERGY INTO CHEMICAL ENERGY

SOLAR-TO-CHEMICAL ENERGY CONVERSION WITH PHOTOELECTROCHEMICAL TANDEM CELLS.

Efficiently and inexpensively converting solar energy into chemical fuels is an important goal towards a sustainable energy economy. An integrated tandem cell approach could reasonably convert over 20% of the sun's energy directly into chemical fuels like H2 via water splitting. Many different systems have been investigated using various combinations of photovoltaic cells and photoelectrodes, but in order to be economically competitive with the production of H2 from fossil fuels, a practical water splitting tandem cell must optimize cost, longevity and performance. In this short review, the practical aspects of solar fuel production are considered from the perspective of a semiconductor-based tandem cell and the latest advances with a very promising technology - metal oxide photoelectrochemical tandem cells - are presented

Solar energy is an inexhaustible source of energy with the most potential as it will continue to produce solar power as long as the sun is there. Solar energy is totally free, widely available, produces no pollution, no emission and no noise which means generating solar power produces no carbon footprint. Among all the renewable energy sources available on Earth, solar energy is one of the most widely used renewable source of energy.Solar energy has wide array of uses. It can be used to produce electricity, to run calculators, swimming pool heating, solar oven or solar cooker. Solar energy can now also be used to fly planes. This technology is however in its initial stage. In the year 2015, Solar Impulse , the first solar powered aircraft, started its Round-The-World flight from Abu Dhabi, on March 9. There is no doubt that solar energy is going to play a significant role in meeting demand supply gap for electricity.

ENVIRONMENTAL IMPACTS OF

SOLAR POWER

• Land Use• Water Use

• Hazardous Materials• Life-Cycle Global Warming Emissions

LAND USE

Depending on their location, larger utility-scale solar facilities can raise concerns about land degradation and habitat loss.

Total land area requirements varies depending on the technology, the topography of the site, and the intensity of the

solar resource. Estimates for utility-scale PV systems range from 3.5 to 10 acres per megawatt, while estimates for CSP facilities

are between 4 and 16.5 acres per megawatt. Unlike wind facilities, there is less opportunity for solar projects

to share land with agricultural uses. However, land impacts from utility-scale solar systems can be minimized by siting them at lower-quality locations such as brownfields, abandoned mining

land, or existing transportation and transmission corridors [1, 2]. Smaller scale solar PV arrays, which can be built on homes or

commercial buildings, also have minimal land use impact.

WATER USE

Solar PV cells do not use water for generating electricity. However, as in all manufacturing processes, some water is used to manufacture solar PV

components.  Concentrating solar thermal plants (CSP), like all thermal electric plants,

require water for cooling. Water use depends on the plant design, plant location, and the type of cooling system.

CSP plants that use wet-recirculating technology with cooling towers withdraw between 600 and 650 gallons of water per megawatt-hour of

electricity produced. CSP plants with once-through cooling technology have higher levels of water withdrawal, but lower total water consumption

(because water is not lost as steam). Dry-cooling technology can reduce water use at CSP plants by approximately 90 percent [3]. However, the

tradeoffs to these water savings are higher costs and lower efficiencies. In addition, dry-cooling technology is significantly less effective at

temperatures above 100 degrees Fahrenheit. Many of the regions in the United States that have the highest potential for

solar energy also tend to be those with the driest climates, so careful consideration of these water tradeoffs is essential.

LIFE-CYCLE GLOBAL WARMING EMISSIONS

 While there are no global warming emissions associated with generating electricity from solar energy, there are emissions associated with other stages of the solar life-cycle, including manufacturing, materials transportation, installation, maintenance, and decommissioning and dismantlement. Most estimates of life-cycle emissions for photovoltaic systems are between 0.07 and 0.18 pounds of carbon dioxide equivalent per kilowatt-hour.

Most estimates for concentrating solar power range from 0.08 to 0.2 pounds of carbon dioxide equivalent per kilowatt-hour. In both cases, this is far less than the lifecycle emission rates for natural gas.

TOP 10 LARGEST INSTALLED SOLAR POWER CAPACITY COUNTRY IN THE WORLD

Rank Country Name Installed (GW)

1  Germany  35.736

2  China  18.528

3  Italy  17.861

4  Japan  13.947

5  USA  12.035

6  Spain  5.375

7  France  4.639

8  Australia  3.524

9  Belgium  3.470

10  United Kingdom  3.316

Q: WHICH IS THE LARGEST SOLAR POWER PRODUCING COUNTRY IN

THE WORLD?

???

??

Germany is the biggest solar power producer country in the world. It is less

expensive and have no effect on humans. It is the most used method

in the world now a days. Hydro is much expensive and nuclear has

very bad effect on human health as it reveals radiations.

TOP 10 LARGEST ELECTRICITY PRODUCER COUNTRY IN THE WORLD

Rank Country Name Production (GWh)

1  China  5,649,746

2  USA  4,260,463

3  India  1,102,941

4  Japan  1,088,684

5  Russia  1,069,593

6  Germany  633,618

7  Canada  626,074

8  France  568,584

9  Brazil  557,963

10  South Korea  534,438

WHAT IS THE FATE OF SOLAR ENERGY???

???

WHAT IS THE FATE OF SOLAR ENERGY???

• Some solar radiation is, in fact, absorbed as it travels down through the atmosphere. Mostly, this is radiation at wavelengths in the two 'tails' of the solar spectrum (Figure 5) - the ultraviolet and the near infrared.

• Like water vapour and CO2, the ozone in the troposphere acts as a greenhouse gas. Unlike those two gases, however, very little of the Earth's ozone is, in fact, in the lower atmosphere; the bulk of it (some 90%) is in the stratosphere, where it forms the so-called ozone layer. In this more-rarefied region, ozone plays a different role because it also absorbs the shorter ultraviolet wavelengths in the solar spectrum - radiation that is lethal to many micro-organisms and can damage important biological molecules, leading to conditions such as skin cancer in humans. Fortunately for life on Earth, most of this radiation is absorbed by the ozone layer, preventing it from penetrating deeper into the atmosphere.

• More pertinent here, the absorption of incoming solar energy by stratospheric ozone heats this region of the atmosphere directly. In effect, the stratosphere is heated from above, whereas the troposphere is heated from below. This is why the highest temperatures are found at the top of the stratosphere, but at the bottom of the troposphere.

WHAT IS THE FATE OF SOLAR ENERGY???

• About half of the incoming near-infrared radiation is also absorbed, mainly by water vapor low down in the troposphere. In addition, the atmosphere contains a huge assortment of aerosols - fine solid particles and liquid droplets suspended in the air.

• Except in the aftermath of a major volcanic eruption (of which more in Section 1.5), aerosols are also most abundant in the lower atmosphere; natural sources include desert dust wafted into the air by wind, smoke and soot from wildfires, salt from sea-spray, and so on.

• Depending on their make-up, aerosols can absorb solar radiation - or (and this is usually more important) scatter some of it back to space. Globally, aerosols make a significant contribution to the Earth's albedo (included in the figure of 31% quoted earlier). They also play another important role.

• Many aerosols act as cloud condensation nuclei, providing surfaces that promote the condensation of water vapor to form the liquid droplets (or ice crystals, at higher and colder altitudes) suspended in clouds - a process that occurs less readily in 'clean' (i.e. aerosol-free) air.

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