Renewable Energy http://www.alternative-energy-news.info But a - - PowerPoint PPT Presentation

Renewable Energy

• Wind Power
• Harnessing wind currents to generate

electricity.

• Hydropower
• Harnessing water movement to generate

electricity.

• Solar Energy
• Gathering energy from the sun to

generate electricity.

• Biomass
• Burning plant and wast material to generate

electricity.

• Geothermal Energy
• Using heat from the earth and resulting

steam to generate electricity.

• Kinetic Harvesting
• Harvesting movement of people,

automobiles, waves, and other moving things to generate electricity.

Solar Power

• What is solar power?
• Power from the sun. Broadly, most forms
• f power are solar; burning plants as biomass

to release the energy stored through photosynthesis, or allowing it to break down and turn to oil, uneven heating creating temperature differences to drive wind and power turbines, and even evaporation of water followed by condensation at higher altitudes creating rivers to spin turbines.

• But a specifjcally focused upon aspect of

solar power is PV systems.

• What are Photovoltaics (PV cells)?
• Photovoltaics, or PV cells, are pieces of

technology that generate electricity by converting solar radiation into electrical current using semiconductors exhibiting a photovoltaic effect.

picture courtesy of: http://www.solarelectricpower.org/power/what_are_pvs.cfm http://www.alternative-energy-news.info

How PV Cells Work

• What they are made of
• Bottom layer of silicon crystal combined

with boron, creating a positive (P) charge.

• Top layer of silicon crystal combined

with phosphorus, creating a negative (N) charge.

• How this makes enegy
• Energy from the sun releases electrons

from both layers.

• Opposite layer charges make electrons

want to move from N layer to Player.

• This movement is blocked by an electric

fjeld created by electron movement on the surface between the 2 layers known as the P-N junction.

• Wires coming from the layers provide a

path for the electrons to follow and complete the circuit, creating electrical energy in the process.

• Photovoltaics, or PV cells, are pieces of

technology that generate electricity by converting solar radiation into electrical current using semiconductors exhibiting a photovoltaic effect.

http://www.mrsolar.com

Types of Cells

• Single-crystal Cells
• Silicon crystal Type
• Silicon Application Type
• Made in long cylinders and sliced into

round or hexagonal wafers.

• Most expensive, and most efficient.
• Makes up roughly 29% of PV cells.
• Polycrystalline Cells
• Molton silicon cast or drawn into sheets

and sliced into squares.

• Medium expense, medium efficiency.
• Makes up roughly 62% of PV cells.
• Amorphous Silicon
• Silicon is applied to glass or metal

surface in thin fjlm making the module in a single step.

• Least expensive, and least efficient.
• Only makes up about 9% of PV cells.

Polycrystalline cell Single-crystal cell Amorphous Silicon cell

Systems

• Stand-Alone System- not connected to grid.
• Grid Connected System
• Direct-Coupled
• Panel system connects to a distibution

panel, connecting system and grid to loads.

• Connection to grid allows the use of grid

electricity as backup and sale of extra power for profjt.

• Power from PV cells runs directly to a DC

load.

• No backup system, only works while cells

recieve power.

• Battery Storage, AC and DC loads
• Power from PV cells can either go directly

to DC load or go to a battery.

• Battery can send power to inverter and

then to an AC load.

• Provides backup system, can opperate

while cells are not recieving power, and can power both AC and DC.

Direct-Coupled system Battery Storage system Grid Connected system

www.fsec.ucf.ed www.fsec.ucf.ed www.fsec.ucf.ed

System Tilt

• Fixed System
• System is located at a fjxed angle that does

not move throughout the year.

• Least efficient, but signifjcantly easier and

cheaper to maintain.

• Adjustable System
• The ability to change the angle throughout

the year to refmect the suns changin altitude provides higher efficiency.

• Higher efficiency, but harder and more

costly to maintain.

• Tracking System
• Sensors and motors allow the system to

always face the sun at optimal angle and offer the greatest system efficiency.

• Highly efficient, but very costly and

complicated to maintain over time.

Fixed

• Adj. 2 seasons
• Adj. 4 seasons

2-axis tracking % of optimum 71.1% 75.2% 75.7% 100%

Tilt Recomendations

• Fixed System Basics
• If your latitude is below 25°, use the latitude

times 0.87.

• If your latitude is between 25° and 50°, use

the latitude, times 0.76, plus 3.1 degrees.

• From initial angle, plus 15° in

winter and minus 15° in summer.

• Adjustable System Basics

Latitude Full year angle

• Avg. insolation on

panel % of

• ptimum

0° (Quito) 0.0 6.5 72% 5° (Bogotá) 4.4 6.5 72% 10° (Caracas) 8.7 6.5 72% 15° (Dakar) 13.1 6.4 72% 20° (Mérida) 17.4 6.3 72% 25° (Key West, Taipei) 22.1 6.2 72% 30° (Houston, Cairo) 25.9 6.1 71% 35° (Albuquerque, Tokyo) 29.7 6.0 71% 40° (Denver, Madrid) 33.5 5.7 71% 45° (Minneapolis, Milano) 37.3 5.4 71% 50° (Winnipeg, Prague) 41.1 5.1 70% Latitude Summer angle Winter angle Avg. insolation on panel % of

• ptimum

25° 2.3 41.1 6.6 76% 30° 6.9 45.5 6.4 76% 35° 11.6 49.8 6.2 76% 40° 16.2 54.2 6.0 75% 45° 20.9 58.6 5.7 75% 50° 25.5 63.0 5.3 74%

Northern hemisphere Southern hemisphere Adjust to summer angle on March 30 September 29 Adjust to winter angle on September 12 March 14

Application to Site

Fixed Angle Results

Month Solar Radiation

(kWh/m 2/day)

AC Energy

(kWh)

Energy Value

($)

1 4.82 435 73.32 2 5.34 433 72.99 3 5.91 529 89.17 4 6.53 559 94.23 5 6.06 538 90.69 6 5.99 508 85.63 7 6.27 542 91.36 8 6.62 567 95.57 9 6.02 504 84.95 10 5.88 519 87.48 11 5.15 446 75.18 12 4.67 415 69.95 Year 5.77 5994 1010.35

Input

City: State: Latitude: 32.48° N Longitude:

• 116.57° W

Elevation: 9 m

PV System Specifications

DC Rating: 4.0 kW DC to AC Derate Factor: 0.770 AC Rating: 3.1 kW Array Type: Fixed Tilt Array Tilt: 32.5° Array Azimuth: 180.0°

Energy Specifications

Cost of Electricity: 16.9 ¢/kWh

Adjustable Angle Results

Month Solar Radiation

(kWh/m 2/day)

AC Energy

(kWh)

Energy Value

($)

1 5.74 521 87.82 2 6.52 530 89.34 3 7.40 670 112.94 4 8.40 727 122.54 5 7.44 669 112.77 6 7.47 644 108.55 7 7.97 701 118.16 8 8.49 738 124.40 9 7.41 623 105.01 10 7.21 641 108.05 11 6.20 543 91.53 12 5.56 499 84.11 Year 7.15 7506 1265.21 http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/US/code/pvwattsv1.cgi

WIND POWER

Is the conversion of wind energy into a useful form of energy, such as using: wind turbines to make electricity or windmills for mechanical power. A large wind farm may consist of several hun- dred individual wind turbines which are con- nected to the electric power transmission net- work. Offshore wind farms can harness more fre- quent and powerful winds than are available to land-based installations and have less visual impact on the landscape but construction costs are considerably higher. Small onshore wind facilities are used to pro- vide electricity to isolated locations and utility companies increasingly buy surplus electricity produced by small domestic wind turbines

BENEFITS

Wind power, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions dur- ing operation and uses little land. As of 2011, 83 countries around the world are using wind power on a commercial basis. As of 2010 wind energy was over 2.5% of total world- wide electricity usage, growing at more than 25% per annum. The monetary cost per unit of energy produced is similar to the cost for new coal and natural gas installations. Wind energy is local. Wind projects keep more energy dollars in the communities where proj- ects are located and provide a steady income through lease payments to the landowners.

CONSIDERATIONS

Although very consistent from year to year, wind power has signifjcant variation

• ver shorter timescales.

The intermittency of wind seldom creates problems when used to supply up to 20%

• f total electricity demand, but as the

proportion increases, a need to upgrade the grid, and a lowered ability to supplant conventional production can occur. Power management techniques such as having excess capacity storage, dispatch- able backing supplies (usually natural gas), exporting and importing power to neigh- boring areas or reducing demand when wind production is low, can greatly miti- gate these problems.

HIGH ALTITUDE WIND POWER (HAWP)

HAWP has been imagined as a source of useful energy since 1833 with John Etzler’s vision of capturing the power of winds high in the sky by use of tether and cable technology. Various mechanisms are proposed for capturing the kinetic energy of winds such as:

• kites
• kytoons
• aerostats
• gliders
• gliders with turbines for regenerative soaring
• sailplanes with turbines
• other airfoils
• including multiple-point building
• or terrain-enabled holdings

HOW DOES IT WORK?

Once the mechanical energy is de- rived from the wind’s kinetic energy, then many options are available for using that mechanical energy: direct traction, conversion to electricity aloft or at ground station, conver- sion to laser or microwave for power beaming to other aircraft or ground receivers. Energy generated by a high-altitude system may be used aloft or sent to the ground surface by conducting cables, mechanical force through a tether, rotation of endless line loop, movement of changed chemicals, fmow of high-pressure gases, fmow of low-pressure gases, or laser or micro- wave power beams.