# Presentation: 568341

## Advances in Photovoltaic (PV) Technology

- National Center for Photovoltaics
- National Renewable Energy Laboratory
- Golden, Colorado  USA
- NREL Seminar, Innovation for our Energy Future, April 10 2008

- 039837

**Bolko von Roedern**

## Acknowledgements

- Past Thin Film program and interactions with subcontractors
- Martha Symko Davies for SAI material
- Long-time SERI/NREL support and feedback (joined SERI in 1983)

## Presentation Outline

- 	PV markets through 2007
- 	PV technologies that are in production and emerging.
- 	PV in the renewable energy portfolio
- 	Assessment and comparison of current PV Technologies

## PV in 2007

- PV NEWS, Photon International, and Navigant Consultants published reviews of 2007 PV market activities
- Around 3700 MW of PV was produced in 2007 (world, 266 MW thereof in the US, @10% efficiency, 37 km2 of modules)
- Thin Film PV reached a market share of >10% world wide, over 60% of US-produced modules.
- US-based Thin Film PV producer First Solar ranked among the top 6 World manufacturers
- China and Taiwan produced 32% of World total

## The US PV companies in 2007

- (1) First Solar: shipped: 120 MW, cap 08: 150 MW
- (2) Uni-Solar Ovonics: 48 MW, cap 08: 120 MW
- (3) Solar World (Shell):  35 MW, cap 08: 100 MW
- (4) Evergreen Solar: 16.4 MW, cap 08: 86 MW
- US total: 266 MW, cap 08: 616 MW (
- Slide considers MW produced in US only

## Concentrator Technologies

- Technologies are ready to deliver
- High and low concentration schemes are possible, low concentration may be possible without tracking
- Systems may require some maintenance, should only be deployed in areas with adequate “direct” solar resource.

## Concentrator technology

- Status 2007: initial commercial installations
- Move from using Si cells towards III-V cells
- A great way to add capacity, makers of high-efficiency cells exist (Emcore and Spectrolab)
- Spain may become initial market
- Until real markets exist, cost/performance of such systems relies on estimates.

## Dilemma

- 	Solar Energy is the only renewable energy technology with enough resource to produce tens of terawatts, but currently is the most costly electricity producer (needs to grow 1000-fold over 2006 production, storage vs. international grid options)
- 	Challenge:  Grow Solar from a very small base, simultaneously add other renewables that are more “resource limited”  but faster-growing.

## Dilemma

- Lower cost renewable energies (wind, biomass) don’t have the resource-base to cover current energy needs.
- Energy harvest:
- 	biomass<wind<solar electric

## Germany through 2006

## Photon International 2010 PV Market Estimates

## DOE/NREL PV contract programs

- In the past:  Thin Film Partnership and PVMatR&D
- Since 2006:  Solar America Initiative

## President’s Goal for the Solar America Initiative (SAI)Making Solar Cost-Competitive Nationwide by 2015

- President’s Goal for the Solar America Initiative (SAI)Making Solar Cost-Competitive Nationwide by 2015

## PV R&D pipeline will support technologies/companies, with funding opportunities calibrated to maturity

## Photovoltaic Technology Incubator Objectives	 

**Explore the commercial potential of new manufacturing processes and products**
- Promote the development of a diverse set of PV technologies which cover a variety of target markets including residential, commercial, and utility power generation.
- Investigate the scale-up potential of promising technology which has already be proven on a small scale.
**Foster innovation and growth in the domestic PV industry**
- Provide U.S. small businesses with a chance to expand quickly in a rapidly maturing industry.  Successful projects will position companies to apply into the second phase of the larger, “Technology Pathway Partnerships” which focuses on full cost reductions to make PV cost-competitive by 2015.
**Establish an efficient and cyclic funding opportunity**
- Funding is structured so that companies receive funding from the Department only upon successful performance of pre-specified new hardware.
- Provide funding opportunities for new applicants every 9 months.
- Perform a stage gate review of funded incubator projects at 9 months.

## Project Development Focused on Improvements at the Module Level

- Project development is focused on a limited number of high impact technical improvement opportunities at the module level that lie on the critical path to scaling-up their technology to full manufacture.
- Full system cost reductions including installation, inverters, and balance of system components is the focus the Technology Pathway Partnerships project currently in phase 1.

## Photovoltaic Technology IncubatorDetails of Selected Projects

**Incubator projects will significantly expand and diversify domestic “market ready” PV technologies:**
**Establish up to 1 GW of annual manufacturing capacity by 2010 of technology which is not commercially produced today.**
**Position 10 U.S. companies competitively among world PV manufacturers by 2010.**
**Projects include a diverse set of technological approaches:**
**Inexpensive and Thin Film Si****	**
**Low and High Concentration**

**Innovative thin film manufacturing**
**Low Cost Multi-Junction Cell Production**

**Selected PV Technology Incubator Projects:**
**AVA Solar**
**Blue Square Energy**
**CaliSolar**
**EnFocus Engineering**
**MicroLink Devices**

**Plextronics**
**PrimeStar Solar**
**Solaria**
**SolFocus**
**SoloPower**

## DOE’s Portfolio Balances Technology, Maturity & Risk

## Guidance for selection

- Lowest-cost levelized cost of electricity
- Use “SAM” to develop appropriate LCOE cost models
- Identify target markets and cost: (a) residential (rooftop), (b) commercial, (c) utility scale

## PV Technologies

- Following slide shows all of them
- Will come back to ordinate (not abscissa) values
- Need to see where technologies are and compare relative value

## Slide 22

## Near-term PV technologies

- “standard” wafer/ribbon Si
- amorphous silicon
- -----------------------------------------------
- “Non-standard” wafer Si
- a-Si (nc-Si) spectrum splitting multijunctions
- CdTeCIGS
- ------------------------------------------------
- Next generation OPV and DSC
- ------------------------------------------------
- Concentrators at all of the above levels

## A Rigorous Scheme for Comparing the Near-Term Potential of Different PV Module Technologies

- We needed to asses real efficiency numbers, knowing that champion cell results and commercial product are well documented.
- Define the c/c ratio as the ratio between verified (stabilized) champion cell efficiency and commercial product efficiency
- Assume that at some point in the future, c/c values of 0.8 will be achieved for all technologies
- Project cost effectiveness ($/Wp) assuming that a thin-film module will avoid Si wafer cost, otherwise cost the same as Si modules.

## Web Survey of (“best”) Flat Plate Commercial Modules (04/08)

| Eff. (%) | Module | T.coeff (%P/oC) | Technology | c/c-ratio |
| --- | --- | --- | --- | --- |
| 19.3 | SunPower 315 | -0.38  | FZ-Si, ‘point contact’ | 78% |
| 17.4 | Sanyo HIP-205BAE | -0.30 | CZ-Si, ‘HIT’ | 70% |
| 15.1 | BP7190 | -0.5 | CZ-Si, ‘PERL’ | 61% |
| 14.2 | Kyocera KC200GT | Only for Voc | MC-Si | 67% |
| 14.2 | SolarWorld SW 185 | Only for Voc | CZ-Si | 67% |
| 13.4 | SolarWorld SW 225 | Only for Voc | MC-Si, | 64% |
| 13.4 | Suntech STP 260S-24V/b |  | MC-Si,  | 63% |
| 13.3 | Sharp ND-216-U1 | not given | MC-Si | 63% |
| 11.0 | WürthSol. 11007/80 | -0.36 | CIGS | 55% |
|   10.4 | First Solar FS-275 | -0.25 | CdTe | 63% |
|   8.5 | Sharp NA-901-WP | -0.24%/C | a-Si/nc-Si | 70% |
|   6.3 | Mitsubishi H. MA100 T2 | -0.2 | a-Si (1-j) | 64% |
|   6.3 | Uni Solar PVL-136 | (-0.21) | a-Si (3-j) | 52% |
|   6.3 | Kaneka T-SC | Not given | a-Si (1-j) | 64% |

## Future commercial module performance based on today’s champion cell results and a c/c-ratio of 80%

| Technology | Future commercial performance | Relative Performance (s.p. Si =1) | Relative-cost/relative-performance (50% thin film cost advantage) |
| --- | --- | --- | --- |
| Silicon (non-stand) | 19.8% | 1.18 | 0.85 (competitive) |
| Silicon (standard) | 17.0% | 1.00 | 1.00 (reference) |
| CIS | 15.6% | 0.92 | 0.54 (highly competitive) |
| CdTe | 13.2% | 0.78 | 0.64 (highly competitive) |
| a-Si (1-j) |  8.0% | 0.47 | 1.06 (about the same) |
| a-Si (3-j) (or a-Si/nc-Si) |  9.7% | 0.57 | 0.88 (competitive) |

## Summary:

- Champion cell results can predict commercial product performance
- Without a 15% efficient total-area stabilized cell, there will be no commercial 10% low-cost module product.
- a-Si/nc-Si will need greater laboratory efficiency to be competitive with competing technologies in the long run
- Near term, all technologies are competitive, thin film modules with efficiencies >9% will lead the way towards lower module prices.
- Concentrator systems, technically ready, would be promoted if a PV growth rate >~40%/per year was mandated.

## >20% efficient commercial cells will only be possible with non-standard processing (HIT, point, PERL contacts) and while using very-high lifetime wafers (>500 microseconds) only achievable with mono-crystalline wafersThere is little or no benefit (for cell performance) processing solar grade wafers using non-standard processing, or using higher lifetime wafers and standard processing

**Si-PV predictions**

## Solar grade feedstock (e.g., fluidized bed process) may not be good enough to make high-lifetime mono-Si wafers for 20%+ commercial cellsThe debate should not be mono vs multi-Si but rather “standard” vs “non-standard” (+high-liftime mono)Cost predictions suggest that very high efficiency will “win” over standard processing.  Thin films with eff. >11% and concentrators >25% are also very competitive.

**Longer-term Predictions**

## Commercialization and Systems

- Thin-Film Modules are used for some large field installations in Germany
- For a Module cost per Watt should be <70%  of x-Si modules, installed thin film system costs will be less than for x-Si systems
- Glass-to-glass(foil) laminates most suited for large field installations

## BIPV and “Special” Product

## 40 MW – Thin Film CdTe Solar Field

- First Solar / Juwi Solar

- Under Construction

- Total Project Price:	Euro – 130 MillionPV System Price:	Euro – 3.25 / WattsCompletion Date:	December 2008

## US-owned, US manufactured modules by technology, crystalline Si and Thin Films (incl. a-Si) 1999-2008

## PVNews reported US production thru 2007

## Conclusions

- Who will win the PV race, non-standard Si, standard Si, or thin-films?
- U.S.-based commercial thin-film PV module production reached a share of 29% in 2005, 45% in 2006 in the U.S., over 60% in 2007, indicating much more rapid growth than crystalline Si PV
- Commercial module performance is increasing based on current knowledge. Today’s R&D will lead to future product improvement
- A sustained growth of PV technology >~40%/year will require more resources than are currently available world-wide.