Solar Photovoltaic Systems - ESF

Solar Photovoltaic

Systems Neal M. Abrams, Ph.D.

Department of Chemistry SUNY ESF

March 7, 2012

Electricity Use and Demand

A Focus on Energy Use

! 1.8x1012 Watts

(continuously)

! 6x109 persons

! 3 100W light bulbs per person

! U.S. – 25% of total ! 15 100W light bulbs per

person

! 36 kWhr/day/person

Solar energy 1%

Biomass 47%

Wind energy 2%

Geothermal 5%

Conventional hydroelectric power 45%

U.S. Energy Consumption

Where are the people? Where is the power?

nasa.gov

Current Supplies

U.S. Energy Information Administration Annual Energy Review 2009

How much do we need?

Area required for all US electricity production (~100 x 100 miles)

Where are the watts?

Matching the Need

!  A 1 kilowatt (1,000 watt) system will generate nearly 1,000 kilowatt hours (kWh) per year of energy in cloudy climates

!  Average consumer utility bill:

!  10,000 kWh/year

!  Reduce your load!

The Magic in the Panel

The Magic in the Panel

! Photons in sunlight hit the solar panel and are absorbed creating a dc source

! An array of solar panels converts solar energy into usable DC electricity. ! Inverters convert the DC to

60 Hz AC to feed for on grid

! Power goes to a charge controller to charge batteries for off-grid

n-layer

p-layer

back contact

anti-reflective coating

front contact

Cover glass

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Anatomy of PV cell

n-layer

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PV System Components

!  Array – Set of PV cells that typically sit on a roof or a pole

!  Inverter – Converts PV DC voltage to AC voltage with very low loss

!  Batteries – Provide backup power for off-grid use !  In a net metering system,

batteries can still be used for backup power

!  Electric meter – Connects the PV array to the grid to support net metering. !  Can spin backwards!

Required Components

On Grid

!  The solar module

!  Inverter (which translates direct current power to alternating current)

!  Associated wiring and support structures

Off Grid

!  The solar module

!  The battery (for energy storage)

!  The battery regulator (also known as a charge controller),

!  Attachment structure and associated connections

! Wiring

On Grid

!  The solar module

!  Inverter (which translates direct current power to alternating current)

!  Associated wiring and support structures

Sunny Boy inverter ETM solar

Off Grid

!  The solar module

!  The battery (for energy storage)

!  The battery regulator (also known as a charge controller),

!  Attachment structure and associated connections

! Wiring

ETM solar

Going off-grid

Batteries

!  Rechargeable batteries are most effective energy storage solution

!  Remaining PV production capacity can be used up by the electrochemical conversion process of the battery.

!  Battery storage capacity is rated in ampere hours

!  Most PV systems use lead acid batteries. Nickel cadmium batteries are newer and have very high reliability.

Charge Controller

!  Used to prevent over- and under-charging of the battery. 

!  Typically necessary if the peak charging rate of the solar module is more than 1.5% of the battery ampere hour capacity.

!  The quality of the regulator is a key factor in the reliability of the overall system. Aligns the depth of discharge with the battery temperature and the rate of discharge.

!  Monitoring current and voltage throughout the system is important for safety and overall system performance.

Anatomy of a PV Installation

Silicon – the benchmark

The Solar Benchmark – 32 %

!  Silicon cells – most mature, most developed

!  80-90% market share

new Apple data center, NC

Photovoltaic types and benefits

! Silicon ! Single crystal silicon (c-Si)

! Multicrystalline silicon (mc-Si)

! Amorphous silicon (a-Si)

! Thin-film (10-20% market share) ! Silicon

! Cadmium telluride, CdTe

! Copper indium gallium diselenide , CIGS ! Very efficient in diffuse light conditions

! Dye-sensitized

Efficiency: How high?

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PV development

nrel.gov

PV Production Payback

!  Current silicon PV technology requires 4 years to generate the energy required to produce it.

! Newer generation PV cells require only 2 years.

Alternatives

!  Other semiconductors: GaAs, GaInP, CdTe, CIGS

!  Thin films and amorphous cells

!  Solar concentrators

!  Dye-sensitized

Costs and Benefits

(39,000 miles2)

Growth

! Market is growing

!  The US on-grid market increased to 914 MW in 2010, a growth rate of 101% over the prior year.

!  California’s share dropped from 51% of the on-grid market, down from 30%, as New Jersey’s and Arizona’s market sizes soared.

!  Led the market for >1 MW system sizes with a 31% share

!  Chinese manufacturers grew their share from 11% to 37% of the US market.

The Growing Solar Industry

Source: Solarbuzz

The solar market grew 20% in 2009, in spite of the economic downturn!

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Silicon Thin film

Module Pricing

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Other issues

! Building infrastructure !  Permits: Electrical and structural

! Neighborhood restrictions !  Beauty and the bulb

! Finding installers

! Maintaining incentive programs

People, places, and politics

Light, people, and politics

!  Sunniest place in Germany has 1250 kWh/m2 per year

!  Syracuse has 1358 kWh/m2 per year (horizontal average)

!  Germany: 8800 MW of PV

!  USA: closing in on 1000 MW of PV

!  Germany has 2.47 times as much area of land and water as NY

!  Population of Germany: 82,422,299

!  Population of NY: 18,976,457

Is it worth it??? nyserda.cleanpowerestimator.com/nyserda.htm

True Market Drivers (current)

! Early adopters

! Perceived benefit

! Feel good, go green

Getting the Job Done

!  PV installations require NABCEP certification for NY state incentives, $1.50/watt, max $10,500

! NABCEP certified programs offered locally

!  Federal tax incentives do not require NABCEP certification

!  Permits required for

!  Structure

!  Electrical connection

Your Name Here

Is PV the complete solution?

Advantages

! Vast, renewable, free fuel source

! No emissions, no combustion, no radiation

! Low operating costs

! No Moving parts

! High reliability

! Modular

! Point of use capability

Disadvantages

! Diffuse fuel source

! High installation costs

! offset by financial incentives

! Poor reliability of system components (inverters, etc.)

! Lack of efficient energy storage

Our Ever Leaking Sun

When there’s a HUGE solar energy spill, we

just call it a “nice day”!