dr. jeffrey s. nelson co-director, center for integrated...

Solar Glitter-Microsystems Enabled PV

Dr. Jeffrey S. Nelson

Co-Director, Center for Integrated Nanotechnologies

Sandia National Laboratories

October 20-21, 2010

Challenges for the PV Industry(DOE Multi-Year Program Plan, NIST Workshop-May 2010)

Silicon:- More efficient use of Si (grams/Wp)

- Move to thinner wafers (<100 m thickness)

- Manufacturing Improvements

Thin-Films:- Overcome performance limitations

- Manufacturable 20% efficient module

Concentrated PV:

- Low cost high efficiency system designs

- Higher efficiency cells (>50%)

- Automated manufacturing and assembly

Organics:- Improved Performance and Reliability

“PV Systems have not

changed much in 30 years!”(NIST Workshop Quote)

PV System Cost

Current Utility

Scale PV Current

Residential

Scale PV

Target

Current PV State-of-the-Art

Concentrated PV (CPV) a-Si

CdTe

Thin-Film CdTe

Opportunities for PV System Cost Reductions

~75% of Module Cost is the Cell

~85% of Cell cost is Materials

PV Learning Curve

Manufacturing Cost Reductions

Rajendra Singh, "Why silicon is and will remain the dominant

photovoltaic material," Journal of Nanophotonics, vol. 3, 032503 (2009), p. 4.

Grid Parity Considerations

Current Grid Parity Solar MarketsHypothetical 2015 Grid Parity Solar Markets

(~2x Lower System Cost)

Grid parity doesn’t assure adoption!

* Capital Cost (another 2x in cost reduction)

* Aesthetics

* Reliability

* …

Solar Glitter: Microsystem-Enabled PV(Sandia R&D Efforts)

Lightweight

Flexible

Rooftop

Utility PV

• Double the efficiency and half the cost

of conventional PV

• high efficiency (cell level >50%,

system level >40%)

• reduced cost (module cost of

~$0.5-1.0/Wattpeak, system cost of

$2-3/Wattpeak).

Thin c-Si PV Cells

10 to 20 m thick; 0.25mm to 1 cm across

Release Thin c-Si PV Cells and Reuse Substrate

Performance of Thin c-Si PV Cells:

14 micor Si Cell

15 % Efficiency

(after 1 year of R&D)

14 micron thick Crystalline Si Cell

Design of High Watt/Gram, Ultra-Thin c-Si & GaAs Photovoltaic Cells

Thin GaAs Cell Performance

Potential Benefits of Small Cells

Thermal

Management

Optical System

And Tracking

Cells on tapeWafer die

Innovative Fab Processes For Assembly

High-Efficiency Concentrated PV Product Platform

Conceptual cross-section of PV cell structure.

This structure removes or reduces many of the

constraints on current multijunction cells.

on order of 1 mm

Small dimensions allow

high-quality, molded

refractive optics

Each junction

independently

electrically connected

Incoming solar

spectrum

Cells grown independently, out of

ideal materials, and proper

thickness for efficient energy

absorption and transmission

Solar Paint and Crystalline Thin-Films?

Figure 4. Non-functional demo of flexible PV structure constructed using c-Si MEPV cells.

High Efficiency Flexible PV Product Platform

• ~0.5 m2 area

• Peak output is 26 W

• Efficiency is <5%

• Cost $334

• Backpack with integrated solar

• Cost $200

• Peak power is 4.5 W

Sandia Approach

More Information

http://www.futurepv.com/node/161

Microsystems-Enabled Photovoltaics:

A Path to the Widespread Harnessing of Solar Energy

Vipin Gupta, Jose Luis Cruz-Campa,

Murat Okandan, Gregory Nielson

Sandia National Laboratories

21

Sandia’s Photovoltaic Facilities

Distributed Energy Technology LabPV Systems Evaluation and Optimization Lab

• Controlled Side-by-Side Component, Array

and System Characterization

• Full-scale cell and module characterization

laboratory

• Comprehensive Data Acquisition Systems

• Grid Integration, Inverters, Combiners,

Disconnects- All Reconfigurable

• Simulate micro-grid or community (25 homes

and businesses), including

•PV

•Storage

•Fuel Cells

•Microturbines

•Diesel gensets

• Testbed for advanced power conversion and

energy management systems

22

Sandia National Laboratories National

Solar Thermal Test Facility

PARABOLIC TROUGH

DISH STIRLING

Questions?