Terawatt Challenge



Yüklə 478 b.
tarix21.08.2018
ölçüsü478 b.
#73519



Terawatt Challenge

  • Terawatt Challenge

    • What is it?
    • Photovoltaics for the TW challenges
      • Importance of rapid growth
      • Recent milestones in PV
    • But what about …..
      • Myths of photovoltaics: land area; efficiency; energy payback time; materials availability; time to impact; duck curves, etc
  • Future prospects

  • Education



Terawatt Challenge: Encapsulates the dichotomy surrounding energy– essential for improved quality of life, but also tied among the most serious global challenges.

  • Terawatt Challenge: Encapsulates the dichotomy surrounding energy– essential for improved quality of life, but also tied among the most serious global challenges.



Why is compound annual growth rate important?

  • Why is compound annual growth rate important?



In the nearly two decades since the TW challenge paper, renewables have reached multiple milestones

  • In the nearly two decades since the TW challenge paper, renewables have reached multiple milestones

  • In US, renewable compound annual growth rate 4.8% from 2000-2012 (NREL data)



Germany, Spain, Italy have yearly installed PV capacity > yearly increase in electricity demand.

  • Germany, Spain, Italy have yearly installed PV capacity > yearly increase in electricity demand.

  • In Germany, PV is 50% of summer peak electricity demand



PV learning curves show compound annual growth rate (CAGR) of ~30% over the last several decades

  • PV learning curves show compound annual growth rate (CAGR) of ~30% over the last several decades

  • Extending the growth rates shows ability of PV (renewables more generally if these are included) to make a substantial impact on electricity generations





ASU – reached 50% of total electricity supplied by PV

  • ASU – reached 50% of total electricity supplied by PV





Energy payback time

  • Energy payback time

  • Land use

  • Cost

  • What do you do at night for power?

  • Materials availability

    • For silicon, limitation is silver in grids, which cause a limitation at 2 TW
    • Availability subject to efficiency, thickness


Power after sun goes down a concern for utilities.

  • Power after sun goes down a concern for utilities.

  • Can mitigate by load management.









Optical configuration of photovoltaic systems: One-sun or flat plate; concentrating systems; tracking

  • Optical configuration of photovoltaic systems: One-sun or flat plate; concentrating systems; tracking





Concentration or stacking multiple solar cells increases efficiency

  • Concentration or stacking multiple solar cells increases efficiency

  • To reach >50% efficiency, need ideal bandgap 6-stack tandem, (assuming ~75% of detailed balance limit).

  • Hard to get compatible materials with the right bandgaps.



Approaches to high efficiency:

  • Approaches to high efficiency:

    • Concentrate sunlight. “One sun” = 1kW/m2, max concentration ~46,000.
      • No entropy penalty for concentrating sunlight, but etendue limits to acceptance angle and concentration.
    • Optically split solar spectrum (i.e. tandem)
    • Beneficially circumvent one of the assumptions in thermodynamics


Key issue for III-Vs: need precisely controlled band gaps which are lattice matched

  • Key issue for III-Vs: need precisely controlled band gaps which are lattice matched

  • “Missing” low band gap material

  • Approaches:

    • Lattice matched; Ge-GaAs-GaInP
    • Metamorphic;Ge-GaInAs-GaInP
    • Metamorphic; GaInAs-GaAs-GaInP
  • Band gaps for 4-tandem are poorly lattice matched;5 band gaps and six band-gaps are better matched



  • Metamorphic solar cell reached 40.7% at ~200X.



Carrier-selective contacts enable ideal VOC

  • Carrier-selective contacts enable ideal VOC



Demonstrated 746 mV on 50 µm wafers

  • Demonstrated 746 mV on 50 µm wafers



InAs QDs achieved on GaAsSb material

  • InAs QDs achieved on GaAsSb material

  • Increasing Sb composition decreases QD size and increases QD density





Monolithic III-V tandem solar cells; Series connected; three junctions

  • Monolithic III-V tandem solar cells; Series connected; three junctions

  • High efficiency used in high concentration, two-axis tracking systems

  • High concentration means small area (and lower cost) needed for solar cells

  • Trade balance of systems and solar cell cost.





Ideal solar cell consists of a light-trapped, thin solar cell

  • Ideal solar cell consists of a light-trapped, thin solar cell

  • Nanostructured surfaces allow light trapping and advanced concepts (e.g., multiple exciton devices)



Silicon pilot line capabilities for interaction among students, industry and researchers

  • Silicon pilot line capabilities for interaction among students, industry and researchers

  • 10 Fulton Undergraduate Research Initiative Projects

  • 2 honors thesis

  • 4 capstone projects



  • Questions?



Yüklə 478 b.

Dostları ilə paylaş:




Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©muhaz.org 2022
rəhbərliyinə müraciət

    Ana səhifə