slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Solar Electricity PowerPoint Presentation
Download Presentation
Solar Electricity

Loading in 2 Seconds...

play fullscreen
1 / 77

Solar Electricity - PowerPoint PPT Presentation


  • 285 Views
  • Uploaded on

Solar Electricity. 14 April, 2009 Monterey Institute for International Studies Chris Greacen, Palang Thai. Palang Thai พลังไท. พลัง (palang): n 1. Power. 2. Empowerment. ไท (thai): adj. 1. Independence. 2. Self-reliance. Thailand NGO Objective:

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Solar Electricity' - sandra_john


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Solar Electricity

14 April, 2009

Monterey Institute for International Studies

Chris Greacen, Palang Thai

palang thai
Palang Thaiพลังไท

พลัง (palang): n 1. Power. 2. Empowerment.

ไท (thai): adj. 1. Independence. 2. Self-reliance

  • Thailand NGO
  • Objective:
    • To ensure that the transformations that occur in the region's energy sector: augment, rather than undermine, social and environmental justice and sustainability.
  • Key approaches:
    • We teach hands-on energy technology
    • We help draft policies
    • We comment on projects and plans
    • We advocate reform in energy planning processes & regulatory regime
outline
Outline
  • Photovoltaics (PV)
    • Basic market trend
    • How PV works
  • Basic types of solar electric systems
  • Grid-connected systems
    • Components
    • Net metering
    • Calculating simple payback
    • (with detour on Peak Sun Hours, array tilt, shading)
  • Off-grid
    • Components
      • Lead acid batteries
      • Charge controllers
      • Inverters
    • System sizing overview
off grid array direct system
Off-grid array-direct system

Image source: Solar Energy International SEI

off grid direct current dc system with batteries
Off-grid direct current (DC) system with batteries

Image source: Solar Energy International SEI

off grid system with ac dc loads
Off-grid system with AC & DC loads

Image source: Solar Energy International SEI

grid connected ac
Grid connected (AC)

Image source: Solar Energy International SEI

net metering
Net metering

Image source: Real Goods

slide15

Net Metering in the USA

www.dsireusa.org / April 2009

WA: 100

ME: 100

MT: 50*

ND: 100*

VT: 250

NH: 100

OR: 25/2,000*

MN: 40

MI: 20*

MA: 60/1,000/2,000*

WY: 25*

WI: 20*

RI: 1,650/2,250/3,500*

IA: 500*

IN: 10*

CT: 2,000*

CO: 2,000co-ops & munis: 10/25

NV: 1,000*

NY: 25/500/2,000*

OH: no limit*

IL: 40*

PA: 50/3,000/5,000*

UT: 25/2,000*

WV: 25

MO: 100

NJ: 2,000*

KY: 30*

CA: 1,000*

NC: 20/100*

DE: 25/500/2,000*

NM: 80,000*

OK: 100*

MD: 2,000

AZ: no limit*

AR: 25/300

DC: 1,000

GA: 10/100

VA: 20/500*

LA: 25/300

HI: 100KIUC: 50

FL: 2,000*

40 states & DChave adopted a net metering policy

State policy

Voluntary utility program(s) only

*

State policy applies to certain utility types only (e.g., investor-owned utilities)

Note: Numbers indicate system capacity limit in kW. Some state limits vary by customer type, technology and/or system application. Other limits may also apply.

slide16

Grid-connected Solar PV

  • System size: 3 kW
bangkok solar 1 mw pv
Bangkok Solar 1 MW PV

Grid-connected Solar PV

  • Bangkok
  • Project size: 1 MW
seasonal array tilt
Seasonal array tilt

36.6 degrees in Monterey

peak sun hours
Peak Sun Hours

San Francisco: 5.4 PSH annual average, tilt at latitude*

1200

1000

800

Watts/m²

600

Peak Sun Hours

400

200

10:00

14:00

16:00

18:00

6:00

8:00

*Source: http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/sum2/23234.txt

energy produced
Energy produced

kWh per year = (PSH) x (peak kW of array) x (solar panel derating) x (inverter efficiency) x 365

Example:

5.4 hours x 2.5 kW x 85% x 95% x 365 = 4000 kWh

grid tied solar simple payback period
Grid-tied solar simple payback period
  • Installed cost  $7K to $9K per kW

2.5 kW * $8,000 = $20,000

  • Value of annual electricity offset:

$0.25/kWh * 4000 kWh/year = $1000/yr

  • Simple Payback:

$20,000 / $1000/yr = 20 years

(assuming no subsidies)

financial sketch mw scale solar project in thailand
Financial sketch: MW-scale solar project in Thailand
  • Project size: 1 MW
  • Cost estimate: $4 million
  • Tariffs:
    • TOTAL: $0.33/kWh for 10 years
  • Simple Payback: 6.5 years
  • 10-year IRR: 14%

Note: project is real. Financials are conjecture. 10% discount rate, 4% inflation

off grid systems
Off-grid systems

DC SYSTEMS

SYSTEMS WITH AC LOADS

solar for computer training centers in seven karen refugee camps thai burma border
Solar for computer training centers in seven Karen refugee campsThai-Burma border
  • 1 kW PV hybrid with diesel generator
  • Each powers 12 computers
slide34

Off-grid system components

Charge controller

Solar panel

Loads

Battery

slide35

Off-grid system components

Charge controller

Solar panel

Loads

Battery

lead acid batteries
Lead Acid Batteries

-

+

  • Two electrodes
    • Negative electrode Lead (Pb).
    • Positive electrode Lead dioxide (PbO2).
  • Electrolyte
    • Sulphuric Acid (H2SO4).
  • Sulfation, equalizing

PbO2

Pb

Separator

H2SO4

flooded lead acid
Advantages:

Water can be added.

Cheapest.

Most common.

Disadvantages:

Can spill.

Hydrogen is vented during charging.

More prone to vibration damage.

Flooded Lead Acid
valve regulated lead acid
Valve Regulated Lead Acid
  • Maintenance Free
    • Similar to Flooded Lead Acid.
  • Gel
    • Silica Gel contains the electrolyte
  • AGM (Absorbed Glass Mat)
    • Electrolyte is Absorbed in a Fiber Glass Mat
lead acid battery types
Lead Acid Battery Types
  • Starting, Lighting and Ignition (car battery)
    • Shallow cycle: 10% DOD
    • Deep discharge drastically reduces battery life.
    • Thin plates maximize surface area and current.
  • Traction – golf cart and forklift
    • Deep cycle: 60% to 80% DOD
    • Thick plates or tubes withstand deep discharge.
lead acid battery cycle life

4000

Deep cycle battery

Cycles to 80% capacity

2000

Car battery

0%

50%

100%

Depth of Discharge (DOD)

Lead Acid Battery Cycle Life
  • Number of cycles to a particular DOD.
  • Cycle life decreases with increasing DOD.
  • Sulphation is the main cause of failure.
battery capacity
Battery Capacity
  • Given in Amp hours [Ah] for a particular discharge rate at 25°C.
  • Empty is usually defined as 10.5 Volts.
  • Usable capacity depends on actual discharge rate and temperature.
charge and discharge rates
Charge and Discharge Rates
  • Written Ct or C/t

Where t = Time = Capacity[Ah]/rate[A]

  • Examples:
    • A 200 Ah battery at 10 amps takes 20 hours and has a C/20 rate.
    • A 200 Ah battery at 2 amps takes 100 hours and has a C/100 rate.
capacity and discharge rate
Capacity and Discharge Rate
  • Lead sulphate forms at both electrodes.
  • H2SO4 turns to water.
  • Discharge rate affects usable capacity.

12.0

C/100

Battery Voltage

C/10

10.5

0%

50%

100%

Depth of Discharge

charging lead acid battery
Charging Lead Acid Battery
  • Voltage is a function of state of charge and charge rate
  • Lead dioxide and lead form at electrodes.
  • H2SO4 increases.
  • Lower charge rates avoid gassing.

16.2

C/10

Battery Voltage

14.4

C/100

12.0

100%

0%

50%

State of Charge

equalizing charge
Equalizing Charge
  • Only Applicable to Flooded Style Batteries
    • Provide a charged battery with a high terminal voltage, ~16V.
    • High voltage causes the battery to “boil”.
    • Lead sulfate is dislodged from plates.
    • Bubbling action mixes up the stratified layers
    • Equalize charge for a few hours at a time
slide48

Off-grid system components

Charge Controller

Charge controller

Solar panel

Loads

Battery

charge controller
Charge controller
  • Ensures that battery is not over-charged
  • For small DC systems, often features a Low Voltage Disconnect (LVD) to ensure that battery is not over-discharged
  • Fancy big ones sometimes have Maximum Power Point Tracking (MPPT) that squeezes more power out of solar panels
three stage charging

Bulk Charge

Absorption

Float

C/20

15 V

Current

Voltage

C/100

Time

Three Stage Charging
  • Reduces the charge rate as SOC increases.
inverter
Inverter
  • Converts Direct Current (DC) to Alternating Current (AC) to power ‘regular’ loads
  • Sometimes includes battery charger
  • Typically can surge to 3X rated power
inverter waveforms
Inverter Waveforms
  • Square Wave
  • Modified Square Wave
  • Sine Wave
back of the envelope steps for designing an off grid solar electric system
Back-of-the-envelope steps for designing an off-grid solar electric system
  • Load analysis
  • Specify capacity of solar panel, battery, charge controller, and inverter (if necessary)
  • Wire sizing
slide59

Solar panel derating: 15%

Loss from Wiring: 3%

Loss from Battery: 15%

wire sizing
Wire sizing
  • Voltage drop – how much power is lost to heat V = I R
  • Ampacity – how much current the wire can safely conduct
slide62
12 Volt 2% Wire Loss ChartMaximum distance one-way in feet Multiply distances by 2 for 24 volts and by 4 for 48 volts.

http://www.affordable-solar.com/wire.charts.htm

wire sizing1
Wire sizing

Typically aim for 3% or less loss

http://www.csgnetwork.com/voltagedropcalc.html

user error bypassed controller battery overcharge
User error: bypassed controller  battery overcharge

1

  • Villager bypasses broken controller and charges battery directly from PV
  • Battery over-charged. Electrolyte level drops and plates are exposed to air. Battery fails.

2

user error controller bypass leads to burned diode
User error: Controller bypass leads to burned diode

1

  • Villager bypasses broken controller and charges battery directly from PV
  • One mistake of reverse battery polarity blows up bypass diode in PV junction box, melting junction box.

2

slide69

Problems found during training surveys

User error: Villager used inefficient60 W light bulb

installation error battery failure caused by solar panel installation in shady location
Installation error: Battery failure caused by solar panel installation in shady location

14:00 Saw Kre Ka village, Tha Song Yang District

slide72

“The Service & Support Department is like the guy in the parade who walks behind the elephant with a broom and a big bucket”

existing linkages

warranty

Existing linkages

Tax payers

$

Ministry of Interior

$

PEA

$

Installation company

SHS

End users

missing linkages

warranty

Missing linkages

Tax payers

$

Ministry of Interior

$

PEA

$

Installation company

SHS

End users

What happens when systems fail?

There is no feedback loop from the end users to installation company, PEA, government or taxpayers

missing linkages1

warranty

Missing linkages

Tax payers

$

Ministry of Interior

$

PEA

$

Installation company

SHS

End users

Feedback on status of systems, failure modes, successful interventions

Warranty awareness

Self-help: local technicians + user training

shs warranty
SHS Warranty
  • Postcards with warranty and maintenance information could be distributed by Tambons
  • Idea presented at meeting with DLA (Department of Local Administration)