This summary of the Photovoltaics portion of the 2022 Solar Energy Technologies Office (SETO) Peer Review covers discussions between reviewers and their discussions with SETO’s awardees. See descriptions of all Photovoltaics projects that were analyzed as part of this review.

The first section covers the overall Photovoltaics review, taking all projects into account. The subsequent sections cover specific topics within the Photovoltaics portfolio.

The following reviewers participated in the Photovoltaics portion of the Peer Review:

  • Richard Swanson (chair, author of the Photovoltaics Overall Portfolio Review section)
  • Robert Opila (lead reviewer, author of the Emerging Cell and Module Technology Portfolio Review section)
  • Terry Jester (lead reviewer, author of the Evolutions of Existing Commercial Technology Portfolio Review section)
  • Olga Lavrova (lead reviewer, author of the Reliability and Durability Portfolio Review section)
  • Peter Borden, (lead reviewer, author of the System Design and Energy Yield Portfolio Review section)
  • Ujjwal Das
  • Aba Ebong
  • Jier Huang
  • David Jackrel
  • Alamgir Karim
  • Lavrova, Olga Lavorva
  • Gon Namkoong
  • Kaushik Rajashekara
  • Steven Ringel
  • Raffaelle Ryne
  • Bayrammurad Saparov
  • Billy Stanbery
  • Barry Thompson
  • Zhifang Wang
  • Matthew White

Photovoltaics Overall Portfolio Review

Goals and Strategy

Reviewers agreed that the goals regarding 2030 levelized cost of energy (LCOE) targets, as well as the overarching goal to decarbonize the electricity sector by 2050, are necessary, appropriate, and achievable with sufficient effort. There is a good balance of support for balance of systems, incumbent technologies, and emerging technologies. Specific recommendations for improvements are embedded below. 

There is less agreement on the best strategy and approach for meeting these goals. The largest source of tension is between downstream needs (balance of system, systems, soft costs, etc.) and upstream (modules, supply chain, and manufacturing tools). Both upstream and downstream needs are covered in the SETO goals; however, the upstream issues are very complex. There is a concern that SETO is relying on an end-run around existing silicon technology to promote a resurgence of onshore manufacturing, an end-run that may not work due to the above issues.

Alignment with Goals

There is broad agreement that the selected projects align with the stated goals. Each of the projects in the portfolio has the potential to increase both PV product production in the U.S., as well as market expansion to meet the SETO near-term goals. To meet longer term goals, additional emphasis on exploring new materials that are at an early development stage may be warranted. 

In the effort to encourage more onshore manufacturing, it would be beneficial for the PV program to have close coordination with the manufacturing and competitiveness program as well as DOE’s Advanced Manufacturing Office. In this regard, special emphasis on strengthening the U.S. supply chain is warranted.

Funding and Resource Allocation

$180 million seems appropriate for the number and scope of projects, as evidenced by the fact that the projects are progressing well. The focus on near-term goals is evident in the project selection. There is the opinion that additional funding could be beneficially used to increase effort on the more exploratory aspects of emerging materials such as perovskites and other thin-film technologies. More focus on building-integrated photovoltaics (BIPV) could be helpful, and supply chain and manufacturing tool support could also be increased, given sufficient budget.

Technical Diversity

Reviewers agree that there is sufficient technical diversity, with the possible exception that perovskites are overrepresented to the expense of all else. While perovskites are a very promising future technology, this is at odds with respect to the goal of increasing onshore manufacturing in the near term. The loss of U.S. presence in the overall value chain, from glass to manufacturing tools, is a serious limiting factor for any PV technology, emerging or incumbent.

Advancing the Mission

The projects support SETO’s mission, but the project teams would benefit from increased industry leadership. Careful thought needs to be given on how best to incorporate industry guidance. In the effort to encourage more onshore manufacturing, it would be beneficial for the PV program to have close coordination with the manufacturing and competitiveness program as well as DOE’s Advanced Manufacturing Office. In this regard, special emphasis on strengthening the U.S. supply chain is warranted.

Areas of Improvement

Perhaps the biggest blind spot is how to realistically bring significant manufacturing on-shore. Besides the above-mentioned need for coordination with the manufacturing and competitiveness program and DOE’s Advanced Manufacturing Office, increased emphasis on the supply chain is needed. One reviewer puts it thus:

“A significant blind spot associated with this topic is really in equipment and commercial module materials development—how to get the cost out of the materials required for 25+ year module lifetimes. Glass is a great example—we need low-cost, highly engineered glass (anti-reflective, highly transmissive, low-energy manufacturing intensity) among other items such as perhaps getting rid of aluminum rails that have been wrapped around modules for over 40 years. Lowering the energy footprint of producing solar modules will ultimately continue to lower cost and bring forward applied material science to keep long warranty and performance periods, while lowering the barrier that the incumbent cell and module materials stacks hold on the industry. It is not an easy problem to solve, but the SETO mission really needs to continue to include this. We also need a robust equipment supply chain to turn machines out fit for purpose in producing the appropriate process recipes and controls needed to grow the industry in the US.”

Stakeholder Engagement

The projects vary in their stakeholder engagement. Unfortunately, typical channels for stakeholder interaction have been muted during the COVID period, which has exacerbated this issue. Care should be taken to ensure that all companies that actually produce solar cells, as well as those interested in potentially doing so, are encouraged to participate. (The PVMaT program, which helped jumpstart the U.S. industry in the 1980s, comes to mind). It may help to seek some nontraditional partners such as manufacturers not involved in PV, but who may have relevant expertise. As an example, the automotive industry has great manufacturing knowhow, which could benefit U.S. cell and module manufacturing. Additionally, the chip industry has vast relevant experience, not only in the manufacturing area, but also in reliability and failure analysis. These, and other important stakeholders such as the glass and silicon materials industries and manufacturing tool suppliers (such as they still exist onshore), should be encouraged to engage.

Final Feedback

Much careful thought has gone into designing the PV program to be as impactful as possible given the budget constraints. This much comes through clearly.

An overarching question is how best to operate in today’s complex PV ecosystem consisting of a huge, fast growing industry whose supply chain is largely offshore, and which is buffeted by diverse political interests, to pursue the important dual goals of rapid decarbonization and energy security? One suggestion would be to conduct several stakeholder workshops that bring a large group of stakeholders together to discuss how best to realize these goals.

A second recommendation is to work diligently to reduce the silos within DOE by maximizing coordination between the PV program, the manufacturing and competitiveness program, and DOE’s Advanced Manufacturing Office. 

And third is to work to broaden the scope to include the entire value chain from glass, to silicon, to manufacturing tools to facilitate continued cost reduction, as well as U.S. competitiveness. 

Of course, all this depends on sufficient budget, so presumably many compromises will be necessary. SETO can’t do everything. It is just that these compromises should be well considered and explicitly acknowledged as the best approach given the budget. While juggling these demands, SETO should prioritize projects that are important for industry, but that industry is unlikely to fund themselves such as the development of advanced characterization tools and long-term reliability studies. In this regard, SETO should continue to support PV process development studies that improve fundamental understanding of materials and device performance.

Emerging Cell and Module Technology Portfolio Review

Goals and Strategy

SETO would like to provide low-cost and reliable solar electricity, leading to solving the climate crisis. SETO does this by funding projects that advance and deploy technology for converting sunlight into electricity. One device that converts solar energy into electricity is the solar cell. One of the most effective ways of improving energy production is by increasing the power efficiency of cells and modules. Reliability and durability of PV systems is also very important. SETO supports improvements in the two major cell technologies, crystalline silicon (c-Si) and cadmium telluride (CdTe) as well as emerging technologies, such as perovskites, and systems that advance the long-term understanding of PV.

This strategy is well-thought-out and is appropriate.

Alignment with Goals

In the broadest sense, all of the projects align with this strategy and its goals. Many of the projects are excellent, however the effectiveness of the projects is limited because these projects do not appear to be interacting strongly with stakeholders or even each other. The distribution of projects is a little problematic. While perovskites are clearly a very promising technology in emerging PV, there were two Si projects, one organic project, two CIGS; and one of the Si projects was for a perovskite/Si tandem cell.  More materials diversity is necessary to cover the field. Within the perovskite portfolio, however, the distribution of projects is very good, and aligns well with goals of SETO.

Funding and Resource Allocation

I think an increase in funding might allow better focusing. The perovskite projects might be around a perovskite center of excellence that would be looking at the current cell fabrication techniques. The smaller projects could look at specific issues, like the role of defects, but bring this information back to the center. Once the perovskite projects were focused, more BPIV, alternative thin film technologies, Si, and other technologies could be supported.

Technical Diversity

As was pointed out above, perovskite solar cells are overrepresented, and everything else is underrepresented. Of course, perovskite solar cells are very promising, but not to the exclusion of everything else. Within the perovskite portfolio, however, the distribution of projects is very good, and aligns well with goals of SETO.

Advancing the Mission

Apparently, the decision has been made that Si cannot be a player in U.S. solar industry, and perovskite solar cells have the best promise for evolving into a domestic PV industry. I think this decision is too narrow. Within perovskites, the distribution of projects, from fundamental defect calculations to roll-to-roll processing, from long-term reliability to the role of grain boundaries, is outstanding and does serve the U.S. solar industry as a whole. However, all the metaphorical eggs are in one basket; if perovskites do not pan out, the U.S. solar industry will be at a disadvantage.

Areas of Improvement

The blind spot, as I have said, is the support of perovskites as a material system, to the exclusion of all others.

Stakeholder Engagement

Some projects are well informed by stakeholder engagement. Unfortunately these projects seem to be the exception. Many projects are isolated at a single institution, and while in themselves may be excellent, the failure to interact with other stakeholders is unfortunate. These stakeholders might include scientists doing fundamental, basic research, as well as companies actually producing solar cells. The latter is particularly a problem in the area of perovskite solar cells as few companies are manufacturing perovskite solar cells. A possible solution might be to fund a perovskite production at NREL or at a center of excellence at a university, while ensuring that there was a path to entrepreneurship.

Final Feedback

  1. Many of the projects are very strong.
  2. Focus the perovskite projects better, perhaps around a center of excellence, or NREL.
  3. Broaden the materials of interest.

Evolutions of Existing Commercial Technology Portfolio Review

Goals and Strategy

SETO is committed to reaching cost targets that support greater energy affordability by cutting the cost of solar electricity 50% between 2020 and 2030. The 2030 benchmark targets are:

  • $0.05 per kilowatt-hour (kWh) for residential PV
  • $0.04 per kWh for commercial PV
  • $0.02 per kWh hour for utility-scale PV

SETO's goals as I interpret them for my topic area covers the continuous improvement of PV products and processes that have been commercialized in order to make said products more efficient, lower cost to produce, more reliable and ever more marketable for companies within the U.S. to create a robust and sustainable business. The whole value chain that can lower LCOE requires careful engineering development, experiments, analyses and ultimately industrialization and implementation to effect lower-cost energy production. Commercial technology evolution is the development of product or process improvements to take to market and create financial value in order to further strengthen the PV businesses in the United States and continue to increase adoption of PV as a clean, cost-effective energy alternative to fossil fuels. To continue to evolve commercialization, research and development projects need to be focused on a short term (<3 year) horizon. This strategy is key for the reemergence of PV manufacturing in the United States where labor, energy, and facility costs tend to be higher than many other parts of the world. Commercial technology evolution for PV in the U.S. needs to be aimed at making companies viable and provide runway for additional revenue (adoption) or gross margin (lower cost or higher price).

Technology commercialization does not only refer to moving a specific “finished technology” to market but may involve commercializing an earlier stage development. Sometimes technology evolution and commercialization require the tools to implement the benefit be developed in a cost-effective manner. This is true for almost all the technologies produced today—PERC (Developed 3 decades ago), TOPCon (1 decade ago), and HJT (2 decades ago). These technologies have been around a long time, and it required industry scale for the equipment suppliers to get interested enough to offer machines that can execute these process steps at an acceptable economic upgrade to the baseline manufacturing processes.

I believe SETO has the appropriate strategy to continue to focus on the ultimate measure of effectiveness, LCOE reduction to a competitive level for widescale adoption and growth.

Alignment with Goals

SETO has stated: Decarbonizing the energy sector will require clean energy technology that can be deployed quickly. Rapid deployment must be responsive to the needs of underserved communities, the solar industry and workers, and the environment. 

To accomplish this, SETO has set the following 2025 goals:

  • A solar workforce of at least 300,000 diverse employees
  • 1 gigawatt per year of new U.S. PV manufacturing capacity installed, based on technology that was not yet commercialized in 2020
  • Installed solar hardware that has at least 40% domestic value
  • Reduce the environmental impact of PV technologies at the end of their useful life by using new materials, designs, and practices, based on a life-cycle impacts benchmark
  • Open new solar markets by ensuring that 1 GWAC of PV installed in 2025 is combined with another use, such as agriculture or building surfaces

Overall, I would assess that the projects managed under this topic do align well with the near term defined goals and strategy. They are all "more advanced" than lab stage ideas, are not aimed at basic research, and work on industry support through material characteristics, material production methodologies, or data analysis to increase PV efficiency and lower cost, all at the cell or module or installed system level.

The goals are being adequately addressed within the current project portfolio. All projects are focused on the lowering of LCOE and the expansion of the market through evolutionary programs. Engineering of optical properties of modules, durability of modules, basic efficiency improvement, and market deployment are present in the portfolio. Each of the projects in the portfolio has potential to increase PV product production in the U.S. and market expansion in the U.S. to meet the SETO near-term goals.

Each project has the potential to deliver more energy and/or lower hardware costs. Projects in total will reduce the cost of PV electricity by increasing the energy a PV system produces over its service life and by reducing the costs to build and operate a PV system.

Funding and Resource Allocation

$180 million is being spent on the PV portion of SETO's portfolio. I believe this a good amount of money that is being wisely spent in the Evolutions of Existing Commercial Technologies section, as each of the projects in the portfolio is aimed at a specific cost reduction for cells/modules or performance improvement via better cell/module efficiency and understanding the performance of systems in the field though large array data analysis and field preventative maintenance items.

Each project reviewed was either on target or close to on target, as the work was well defined at the beginning of the project work. The teams appear to be well-rounded and capable overall. The portfolio size seems manageable from a SETO standpoint. The reviewers were all able to get the projects assessed, meet with the project team leader as needed and get the written reviews in on time in this section. Again, the focus on near term, industrially implementable projects is clear throughout the breadth of the projects being worked.

Technical Diversity

There is appropriate industrial diversity in the breadth of projects spanning from predictive maintenance optimization to maximize the economic operations of PV plants (with Arizona Public Service Utility) to foundry support (ASU/GaTech), to bifacial improvement of CdTe modules to new wafer technologies to eliminate kerf losses in silicon ingot/wafer production.

There is appropriate technical diversity from CdTe to Crystalline silicon (PERC, TopCon, HJT) to III-IV materials to CIGS, from hardware to process detailed measurement techniques to modeling and big data analysis. Tandem and single junction devices as well as measurement details that can benefit the industry in bankability and predictability are also included in this section, as well as a program to educate PV science grad students across the country to NREL's capabilities to further their impact related to PV.

Advancing the Mission

The projects do support SETO’s mission, but the overall findings from two years ago still hold true—the project teams need “Increased industry leadership for Commercial PV Technologies projects (not just a letter of support, but guidance, active participation, and commitment). Reviewers expressed multiple ideas of how this might be implemented, including that each project could be required to have a task that describes how the interaction with industry is handled, especially for large projects that are designed to help transform the U.S. solar industry.”

As the near-term goals are to build an industry to hire 300,000 people and to increase capacity of installations by 1 GW/year, we need active industry participation to make sure these projects are extensions of their needs and are focused and accepted by industrial leadership.

Areas of Improvement

A significant "blind spot" associated with this topic is really in equipment and commercial module materials development—how to get the cost out of the materials required for 25+ year module lifetimes. Glass is a great example—we need low-cost, highly engineered glass (anti-reflective, highly transmissive, low energy manufacturing intensity) among other items such as perhaps getting rid of aluminum rails that have been wrapped around modules for over 40 years. Lowering the energy footprint of producing solar modules will ultimately continue to lower cost and bring forward applied material science to keep long warranty and performance periods, while lowering the barrier that the incumbent cell and module materials stacks hold on the industry. It is not an easy problem to solve, but the SETO mission really needs to continue to include this. We also need a robust equipment supply chain to turn machines out fit for purpose in producing the appropriate process recipes and controls needed to grow the industry in the U.S.

Stakeholder Engagement

There continues to be the need to focus on industrial partnerships. There can never be enough collaboration between ideas, testing, cost predictions and execution between researchers and industrial partners. The U.S. leadership in PV must nurture this tight bond or the work will falter and only exist on paper, not embedded in products and business success for the U.S. PV Industry. The projects are well-informed by the appropriate level of stakeholder engagement, the dissemination of the work is hard during a time like these last years with COVID. Typically, conferences and specialty meetings can help keep stakeholders informed, again hard these last few years. As mentioned above, stakeholders, organizations, or collaborations missing in this topic area includes a more focused effort to get equipment suppliers involved and materials suppliers who are critical for success, such as glass producers.

Final Feedback

SETO’s mission is an important one and invaluable to a growing industry. It is asking the questions that many companies cannot or will not ask with regards to “white space” projects that the nearly zero margin businesses have a tough time addressing. In my 40+ years in this industry, I have always been impressed with the integrity and professionalism that the staff exudes in SETO.

Reliability and Durability Portfolio Review

Goals and Strategy

Within the DOE’s SETO, PV office goals are:

  • Decarbonize electricity generation sector by 2035, and have 100% clean energy economy with net-zero emissions by 2050;
  • Within that scope, lead innovation and development of new solar generation technologies, as well as assist with innovative and traditional technologies and their transition to economies of scale, in order to realize lower LCORE.

Specifically, 2030 SETO PV goals are:

  • PV electricity costs less than 2c/kWh
  • Seamless integration with other land uses
  • Reduced overall PV system life cycle impacts

SETO MYPP concentrates on:

  • Continuing cost reductions for incumbent technologies
  • Silicon, CdTe
  • Improvements in system yield
  • Transition to bifacial, extended system operational life
  • Solutions that expand viable siting and improve installations 
  • Varied terrain, canopy, floating
  • Improvement in module performance 
  • Tandem modules, perovskites
  • Increased focus on sustainability
  • Supply chains, end-of-life considerations

Most of the reviewers agreed that the strategy is appropriate and is aligned with a number of current administration priorities, as well as with needs of climate change awareness. However, several comments have been raised that not enough is being done or that SETO’s roadmap and goals are more aligned with “business as usual.” Some reviewers expressed an opinion that all priorities, including SETO’s, need to be radically reconsidered to be even more transformational, in order for the United States and the rest of the world to be able to avoid the extreme tail end of the climate change projections.

Alignment with Goals

All reviewers agreed that the projects selected and managed under this topic are indeed well aligned with the goals and strategy.

Funding and Resource Allocation

All reviewers agreed that the number of projects and funding levels are appropriate. There were several recommendations, such as:

  • Fund more of fundamental science/ breakthrough technologies
  • One specific project (Duramat) was noted for producing seemingly low number of publications, patents, and/or similar productivity metrics given significant federal funding level.

Technical Diversity

There is a good technical diversity, from funding fundamental materials research, to funding of innovative manufacturing processes, as well as characterizing PV modules and balance of system components reliability and lifetime.

Advancing the Mission

All reviewers agreed that the projects and diversity do serve the needs for the U.S. solar industry. One reviewer noted that even more can be and should be done to ensure re-shoring of solar industry manufacturing in the United States.

Areas of Improvement

Reviewers did not identify significant blind sports, but here are some suggestions for improvement as mentioned by reviewers:

  • Are there any specific efforts to make reduce the environmental cost of creating solar/storage? A lot of the people who oppose 100% renewables argue that the environmental cost of creating/disposing solar panels and batteries is higher than its benefit. This is an area/opportunity for getting the correct information to the public/consumer.
  • Exciting to see increasing work on end-of-life. Some skeptics also point to embodied energy for solar and other technologies. Is there a plan to pair debunking such myths with these end-of-life advances to cover the entire lifecycle?
  • U.S. should aim to see significant job growth in the manufacturing sector to become the global leader in the solar PV and energy storage technology supply chain. Need more effort on re-shoring of solar and storage manufacturing sector in the U.S.
  • As more industries (e.g. apparel, shoes) develop products that can be easily broken down into single-material parts, it might be interesting to take a system-level perspective to see what other industries used solar materials can go into—and be sourced from.
  • Did not see any projects looking at roadways or bikeways deployments. There are both roadways and bikeways deployments in Europe, so it would be good for U.S. to not lag behind on this.
  • Reliability – some projects and researchers are re-inventing the wheel. A lot of reliability approaches, metrics, etc., have been developed and excelled at in other manufacturing sectors (automotive, similar semiconductor manufacturing (silicon microprocessors)). How do we learn from our previous lessons? How can we warrant reliability, durability, and lifetime for all new technologies, without waiting 30 years? Feedback: fund more methodologies for reliability, not just observation. Also, find a way to increase sample sizes. Much closer connection with manufacturers will be helpful in this area.
  • Better connection between NREL’s PV fleet and NREL’s acceleration lifetime work will be beneficial. For example, is there information that reliability standards informed by NREL’s acceleration lifetime work yield longer lifetimes, as measured by PV fleet efforts?
  • Will need the same informed reliability and lifetime estimation approach to perovskites. Perovskites are a new technology, and this is a good opportunity to build in “reliability by design” concepts into manufacturable perovskites designs, rather than repeat the “observation for 30 years” approach as we did with silicon.
  • Is there a way to quantify that projects funded via Duramat (versus regular SETO FOAs) are producing better results (in terms of guaranteeing better lifetimes and reliability)? If there is no quantifiable difference, then Duramat consortia may need to reconsider strategy for selecting and funding the projects.
  • Feedback to SETO: include the language in FOAs that require use of industry-accepted statistics approaches and methodologies, such as: “FMEA, RPN or Pareto analysis needs to be demonstrated.” Include language about applying T-test and calculating p-value to make sure results are quantifiable. Apply rigor to calculation of uncertainty.
  • MPLE seems to have been missing in this round of projects. A FOA concentrating on MPLE could be a good opportunity to align SETO’s research roadmap with wide-bandgap materials.
  • Machine learning for system design could be an interesting area to explore: given all the body of knowledge we have about PV system’s operation, maintenance, and reliability (string configuration, inverter configuration, climate locations), can we use ML to predict the best/optimal configuration for PV plants for different climates, etc.?

Stakeholder Engagement

Both SETO and all project awardees seem to be engaging the right stakeholders. A broad outreach and a wide collaboration with stakeholders was noted throughout all projects, so there are no “blind spots” here. Some projects have formed Industry Advisory Boards, which are a good channel to communicate with and disseminate information.

Additionally, SETO’s prioritization of open source tools and open datasets is very important; it is good to see all project awardees following this trend.

Some individual projects’ reviews have noted that even broader interaction with BOS manufacturers and PV system owners and operators would make the projects more impactful (there is never too much communication).

Final Feedback

  • PV has much more value and better serves equity objectives when deployed in large, grid-congested cities. We recommend that SETO put more emphasis there.
  • SETO is working with HUD to overcome barriers to multi-family affordable housing and starting the development of a platform to connect energy assistance households and community solar. Can SETO partner with HUD to advance the program so you can deploy at affordable housing and advance job training under Section 3? Can you access data on households that accessed energy assistance from the states to target aid?
  • Has SETO measured, and does SETO have targets for diversity in leadership? Are there programs such as mentoring and coaching to support and empower emerging diverse talent?
  • There’s a strong need for a separately funded research funding stream from SETO/EERE for advancing energy justice.
  • Cross-collaboration efforts within DOE offices are even more important: SETO+VTO (solar on vehicles), etc.

System Design and Energy Yield Portfolio Review

Goals and Strategy

The overarching goal is to avert environmental catastrophe through decarbonization by 2050. A major component of decarbonization is the proliferation of photovoltaics (PV) driven in part through cost reductions, and a significant opportunity is to realize 1.6¢/kWh LCOE reduction from the 4.6¢ 2020 baseline through improvements in balance of systems (BOS) costs. This is a major fraction of the overall target of 2.6¢. 
 
The BOS contributes to domestic job creation and development of domestic industry. There is additional opportunity if BOS component manufacturing can be brought back to the U.S.
 
The strategy involves targeting a number of aspects of BOS costs and performance, including better energy estimates to facilitate financing and project planning, better monitoring and diagnosis of systems, and improved components (mounts, configuration, power electronics, trackers).
 
This is an entirely appropriate area of investment. As module costs drop, the BOS becomes an increasing fraction of the overall system cost, and is therefore critical to making PV an attractive component of the push to decarbonize.
 
However, because the PV industry is mature and most of the component suppliers are off-shore, it is challenging to choose appropriate investments in improvements to the existing infrastructure that will make a significant impact.

Alignment with Goals

It is unclear how well the chosen projects align with the defined goals and strategy. I have not seen a Pareto analysis that prioritizes where investments can have the greatest effect, where each program lies in that ranking, and the projected LCOE reduction resulting from the successful completion of each program. For example (and this is not meant as a criticism of any single program), one slide deck attributes $13/kW to operating and maintenance (O&M) costs for a 10 MW array, or $130,000 for the entire array. This is about the cost of two maintenance personnel (the minimum required for safety). As that project targets O&M cost reductions, it is hard to see how it could lead to a major reduction in LCOE.

If such a Pareto analysis exists, it would benefit each program to know how they align with it, so they can appropriately direct their efforts. Otherwise, it would benefit SETO to have such an analysis as a guide to direct future investments.

Funding and Resource Allocation

The number of projects is appropriate and manageable, which will help to yield a higher quality result. The funding levels seem in line with the effort for most projects. One project involving a professor and graduate student doing a paper study has a high budget compared to similar efforts; whether this is out of line is difficult to say without more detail.

Technical Diversity

Lack of technical diversity is a serious issue. Each program needs to ask the questions, "Has someone else solved this problem, what can I learn from them, and can I enlist their help?" For example, one program deals with bolt failures. The aerospace and automobile industries have figured out how to reliably join metal panels that undergo far more stress than solar panel mounts. Other programs reinvent the wheel in reliability and lifetime engineering, without using methods that have proven successful in the semiconductor, automobile, aircraft and other industries.

Advancing the Mission

Most of the solar components industry is off-shore, and programs to improve existing components may benefit those off-shore manufacturers more than the U.S. industry. Developing best practices may make it easier to finance systems, but it will not bring the industry back.

It may be advisable to rethink how SETO approaches its mission. In the reviewer discussion, Dick Swanson brought up Clayton Christenson's ideas (see his book, "The Innovator's Dilemma") as a way to revive the U.S. industry. This has real merit: promote activities in niche consumer markets underserved by incumbents as a way to break into a large but mature market. SETO should engage Prof. Christenson (he's at Harvard Business School) to advise on how this can be done in our industry.

Areas of Improvement

Some program definitions create boxes that limit creative thinking. For example, one program deals with reliability of bolts. If one thinks about fasteners rather than bolts (i.e., the function rather than the specific device), then alternate approaches such as riveting (used extensively in aerospace) or spot welding (used extensively in the automotive industry) become candidate solutions. Similarly, another program targets connector reliability. If one thinks instead about interconnects, candidate solutions might include soldering, screw clamps, or cables without connectors. 

I realize that the programs in many cases follow the advice of user panels, but sometimes it may be necessary to independently test that advice. For example, connector failures were identified as a critical issue, and I do not have the experience to dispute that input. However, a 20 MW field might have >100,000 connectors, so one failure a month is an annual failure rate of only 0.01%, a rate so low that significant improvement may necessitate a more expensive connector and extensive, time consuming evaluation before deployment. So realizing an improvement in connector reliability may end up being a large project with relatively little effect on the deployment of PV in the U.S. This may be better left to the connector suppliers, who are largely foreign based, as they strive to meet customer needs in a competitive market.

Stakeholder Engagement 

This was brought up in a previous section: Each program needs to ask the question "Has someone else solved this problem, what can I learn from them, and can I enlist them to help me?" There are several examples where engaging industries such as semiconductor fabrication, aviation, or automobile manufacturing might provide attractive, proven solutions.

It would help to have a way for industry to have some "skin in the game"—that is, a financial incentive to engage in programs. This might promote more active and ongoing engagement. It might also encourage U.S. industries with relevant expertise who are not yet in PV to consider developing products for the PV industry.

Final Feedback

SETO plays a vital role in training a cadre of experts, the value of which cannot be understated. University programs maintain the U.S. lead in higher education. The national labs are a tremendous storehouse of knowledge, and could benefit from programs that allow them to bring in postdocs, students, and trainees.

Several programs measure aspects of performance of a system or aggregate of systems but fail to provide information needed to assess the value of the measurement. This includes: 

  • What is the sensitivity of the measurement?
  • What is the repeatability and reproducibility of the measurement (the short- and long-term accuracy)?
  • Does the measurement respond to a single parameter, or can multiple parameters confound the result?
  • If the measurement detects an excursion, is there an available response?
  • How does the measurement provide improvement over existing measurements?

See more review summaries from SETO’s 2022 Peer Review.