NREL Module Efficiency - Then and Now

In April 2009 I began my career in the solar industry with Eos Energy Solutions, a small PV installation “start-up” out of the owner’s house near Center City Philadelphia. I no longer work directly in solar, but it’s still a passion of mine. During this time I recall looking at NREL’s “Best Research-Cell Efficiencies” graph trying to decipher the different technology and compare it to what we were installing. Below is the 2005 graph - I had this printed and pinned to the wall near my desk.

Image courtesy of NREL.

It’s now 2020, more than ten years later, and I was wondering what that graph looks like now…

Image courtesy of NREL.

We mostly installed mono and multi-crystalline with some thin film mixed in. In 2005, mono and multi efficiencies peaked at around 24% and 19% respectively. In the 2020 graph, mono and multi efficiencies were about 26% and 23% respectively. Modest gains for sure in the crystalline silicon sub-sector, but really impressive gains in the multijunction sub-sector with peaks in the high 30s for non-concentrators. It’s also great to see so many more technologies being tested and pursued. If you’re curious what some of these technologies are, NREL has good summary on the topic. Or if you are interested in what other PV research NREL is working on, follow this link. For the crystalline silicon market, and for those customers looking at installing PV on their house or business, does the efficiency plateau mean most commercially available modules are closer to the upper-bound efficiency now? (In 2009-2014 I recall most efficiencies in the 14-16% range.) Or because we’re pushing the theoretical efficiency limit, and there is no cost-benefit to improve manufacturing process to realize the small cell gains, price stratification has remained the same? In another post I’ll do some $/watt comparisons to see how the market has changed.

Observations on Construction Submittals

Per the AIA (A201, General Conditions of the Contract for Construction), the purpose of submittals are “to demonstrate for those portions of Work for which submittals are required, the way by which the Contractor proposes to conform to the information given and the design concept expressed in the Contract Documents.”

Submittals are the confirmation of the contractor’s intent to comply with the design concept.  The importance of this compliance process is emphasized by the prerequisite condition stated in A201:  “The Contractor shall perform no portion of the Work for which the Contract Documents require submittal and review of Shop Drawings, Product Data, Samples, or similar submittals until the respective submittal has been approved by the Architect.”

At a minimum, designers should be generating construction documents that contain enough detail that clearly demonstrate a design intent.  Additional detail from designers - equipment or process specifics - is beneficial but not critical to project success (albeit with a higher risk of overages).  For projects with expedited project timelines (design-build, EPC), minimum designer input dictating general sizing, spatial relationships, and arrangement can be enough information to advance project steps.  In these scenarios, the submittal process can be utilized by the designers to fine tune a design and verify system coordination to ensure performance needs are met.

However, on standard or typical projects, submittals are not intended to be an opportunity to alter the design concept by either designer or contractor, but the reality is they often function in that capacity.  This 2006 AIA article takes it a step further describing the process as a game between the design and construction teams.  While most may treat it this way – a cat and dog fight – the analogy cuts to the root of many of the process’s problems.

Image courtesy of Looney Tunes

The reality is submittals and the submittal process are really critical to project success.  It represents one of the last opportunities to make changes (large and small) without causing a compounded affect to cost.  For a seemingly typical and simple process, the problems are well rooted in construction culture and are still largely evident.  The workflow has improved recently with shared project management software, but there are still efficiency gains to be had.

A case study authored by Catarina Pestana and Thais Alves of San Diego State University titled “Study of the Submittal Process Using Lean Construction Principles” did an analysis of submittal cycle time for a 12-story, 220,000 sf, mixed-use, CIP concrete new construction project in San Diego, CA around 2010.  They were able to calculate actual cycle times at each process step (GC initial review, A or A/E review, GC distribution) and compare against estimated times.  Most of the results were expected: actual lead times exceeded estimated, actual lead times average and median were about 32 days.  A few of the surprise findings were:

1. The GC distribution cycle time exceeded GC initial review cycle time by about 3 days.

   1. Submittal distribution is expected to be the least burdensome step as it should require less technical review than the other two.

2. Shop drawing review lead times (generally more complex) were about 10 days less than product data reviews.

   1. Shop drawings are generally more complex and thus the expectation would be for a longer lead time.

3. Architect-only review lead times on average were 12 days longer than those also requiring the review of an engineer.

   1. Because an A/E review requires additional hand-off to/from the engineer, it would be expected that the cycle time would be longer.

Interestingly, it was the GC review and distribution that caused the difference in lead times for both 2 and 3 above; the cycle time for the design professional review was the same for both.  In this study, the longer distribution times were attributed by the contractor to “the architect finishing the design”, thus requiring change orders (part of the change order process was incorporated into the “distribution” step).

 From my experience, here’s where I see waste in the submittal process:

1. A submittal is received that did not follow the compliance requirements.

2. A submittal is incomplete (covers only part of system/equipment).

3. A submittal is poorly labeled; it is unclear what is being submitted on.

4. A submittal is submitted in the wrong sequence (a sub-component to a larger component that has yet to be submitted on).

5. A submittal is submitted that is not required.

6. A submittal is disguised as a substitution request.

7. A submittal is not previously reviewed by the GC.

8. A submittal is overlooked or forgotten (all parties guilty here).

9. A submittal is not applicable to the project at-hand.

10. A submittal is provided by a project team member deep down the contractor org chart (sub-vendor to a vendor to a sub-subcontractor to a subcontractor to a GC).

From my experience, here are a few solutions to minimize submittal process waste:

1.  Require a standardized control number for all parties involved.

   1. Why?  This improves coordination, avoids confusion, and eliminates the unnecessary step of manually creating/adding/altering unique control numbers.

2. Require the GC generate a schedule of submittals prior to issuing submittals and have it reviewed by the design team for completeness.

   1. Why?  This gives the design professionals an opportunity to ensure all critical components/equipment/systems are accounted for.

3. Specs should clearly describe what submittals are needed.

   1. Why?  While the general spec format is standardized, how specific submittals are requested is oftentimes determined by the architect (and is not standardized).

4. Specs should clearly describe how submittals are to be replied.

   1. Why?  Compliance statements clarify communication between contractor and designer.  The designer can verify that the contractor reviewed the specification and the contractor can explain why their product or drawing deviates from spec.

5. If sub-subcontractors or sub-vendors are utilized, it should be the responsibility of the prime subcontractor to directly issue and manage all relevant submittals.

   1. Why?  Each document hand-off step is an opportunity for delay, increasing the probability of a longer cycle or lead time.

6. Change workflow such that any obvious consultant items are sent direct, bypassing the architect “review” step.

   1. Why?  Oftentimes submittals for engineer review get hung-up with the architect for no reason other than they are busy.  Eliminating this step can decrease cycle and lead time.

7. Change the workflow such that submittal reviews are two-step.  Step one is a cursory review for proper formatting (stamps, equipment labeling, compliance statements) and should have a 2-4 day lead time.  Step two would consist of the full review which would carry that same lead time.

   1. Why?  Where is the value in waiting 8 days for a submittal response that will ultimately get rejected on a technicality after a 15 minute review?

8. Designers to provide clear, listed responses that can be tracked over each issuance.

   1. Why?  The submittal comment format is not standardized and oftentimes comments are buried in the documentation.  Cleanly formatted lists ensure all comments will be visible to the receiver.

9. Set a goal for no more than two re-submittals.  The third should be for record only.

   1. Why?  Goals help “set the tone” or set expectations for all project parties.

10. Triage submittals by categories “Ordinary”, “Semi-Custom”, “Specialized” to indicate product lead times.

    1. Why?  Categories can signal to the submittal reviewer approximate time to review or criticality of review.  For example, valves labeled “Ordinary” would signal a short review, whereas a pump labeled “Specialized” would signal long delivery lead time and expedited review.

11. GC to expedite the first submittals for larger equipment that are anticipated to undergo multiple reviews.

    1. Why?  Initial submittal steps after the log is generated should be to prioritize submittals for larger/more complex equipment with long lead times.

12. GC to reduce expected review times on R&R resubmittals.

    1. Why?  The first submittal review on average should take longer than second or third reviews. The second or third review should be intended to verify earlier comments are addressed.

Construction is a Manufacturing Process - Part 2

Most of us (reading this post) work in the construction industry, or the AEC (Architecture, Engineering, and Construction) to put it more broadly.  Whether you are a designer or builder, the goal is generally always to construct (let’s ignore academic architects for the time being).  And in construction, the ideal process includes the procurement, delivery, and installation of materials in a non-disruptive sequential order, per the design specifications, that together create a functional system satisfying the design intent (that’s a mouthful).  In short, we want to get the right material on-site at the right time so that it can be installed by the contractor without screwing up work performed simultaneously by other contractors – get in and out as quickly as possible.  “Getting in” is easy, it’s the “getting out” part that is a challenge.  “Getting out” isn’t just turning on power and walking away, it’s the successful integration of all components whether its envelope layering or boiler feedwater controls.  It is this 10% of a contract requirement that can be the most stubborn and costly for owners and contractors.  Does the end product meet or exceed the design intent?  Is the owner satisfied?  Here’s how thinking like a manufacturer can help.

As mentioned in the prior post, construction is a project type manufacturing process with the end product a building, facility, or structure. Traditional manufacturing, out of necessity, has become more and more efficient at delivering the same product at a higher quality for less. They have taken the deep dive down the lean rabbit hole and are not looking back…

Here are a few ways we can continue to align construction with traditional manufacturing and shatter efficiency targets:

1. Expand the use of 3D CAD.

   1. Collaborative designing and BIM accelerate the design process, expediting iterations and avoiding major material conflicts.

2. Incorporate testing requirement expectations.

   1. Commissioning has become more common, but still not every contractor expects it. Embed it in the contract and specifications before issuing to bid.

3. Make clear ALL expectations.

   1. Relieve some of the contractor errors or coordination complications by clearly communicating every expectation and watch costs come down. If everyone is making money, the market will weed out the greedy.

4. Start tracking costs better.

   1. Knowing at a granular level that the chiller cost on job Y was 2x the cost on job X, or the labor to drywall 1000 SF was 1/3 the cost on job W is very powerful. Eliminate the mystery behind estimating to achieve optimal value.

5. Prefab more components.

   1. With BIM, many field fabricated components can be shifted to a shop environment where quality control is heightened.

6. Build modular blocks in controlled environments.

   1. Take prefab one step further by building self-supported rooms or spaces offsite, rigging into place at site, constructing the superstructure and finishes simultaneously.

7. Introduce more industry standardization.

   1. Both on the material side and the technology side (how many different construction management softwares do we need to learn?)

8. Utilize Integrated Project Delivery (IPD) or other multi-party contracts.

   1. These are the best mechanisms for changing how things get built.

9. Accept the truth behind all meetings and re-evaluate.

   1. When you realize most meetings are held to inform 1-2 people, you realize there is a better way to approach the problem of communication.

10. Lastly, teach architects that it’s OK not to be different all the time!

    1. Seriously, not in all cases, but if architects had a better understanding of the implications of their decisions, I bet our built environment would look very different.

Construction is a Manufacturing Process - Part 1

Image courtesy of Guerdon Modular Buildings

In the manufacturing sector, “process selection” per Jacobs and Chase, authors of Operations and Supply Chain Management, refers to the “strategic decision of selecting which kind of production processes to use to produce a product or provide a service.”  The process is generally selected based on production volume which is a function of customization.  If you produce high margin, low volume product, manual assembly may be a good fit.  If you produce low margin, high volume product, a continuous assembly line is probably best.

Manufacturing process can be placed on a spectrum in order of production volume and customization:

1. Continuous Process.  Highest yield, typically a commodity.

   1. Ex. Petroleum refinery, chemical processing, etc.

2. Assembly line.  Work processes are arranged according to the progressive steps which the product is made.

   1. Ex.  High volume items where specialized process cannot be justified.

3. Manufacturing cell.  Dedicated area where products that are similar in processing requirements are produced.

   1. Ex.  Metal fabrication, computer chip manufacturing, small assembly work.

4. Workcenter/Job Shop.  Similar equipment and functions are grouped together.

   1. Ex. Small part quantity toy where stamping, sewing, and painting are performed separate from assembly.

5. Project.  Lowest yield, mostly all custom product.   Manufacturing equipment is moved to the product rather than vice versa.

   1. Ex. Home, plant, building, bridge construction; movie shooting lots

When was the last time you thought of a construction project as a manufacturing process?  Probably never.  Why do we think that is the case?  And is it not right to think that way (why does it matter)?

Courtesy of GettyImages

I’ve been thinking a lot about these questions over the past year as I’ve floated in and out of multiple construction projects.  As a consulting engineer I perform project work.  We are hired for a defined task or tasks, we execute on that task, and we then move on.  And when I’m a team member of these projects, I’m party to the confusion, headaches, and wastefulness that so often accompanies construction.  So as a value-oriented individual, I can’t help but notice as a manufacturing process, we’re so far removed from typical manufacturing culture including all of the efficiencies they offer.

Think about what a “project” manufacturing process might qualify as – a standalone, custom/unique assembly of high quantities of components in a complex sequence – which is basically a building or facility.  If our “product” is a house or lab or office, the process to “assemble” (build) is no different than the process to “assemble” (produce) an automobile or can of soup or a gallon of gasoline.

I believe it, and so do some forward-thinking individuals at the Lean Construction Institute, but construction has been dogged by hardened behaviors resistant to change.  Anyone from the lowest level laborer to the project executive can point to areas of gross wastefulness in construction.  When we think about construction like Ford thinks about SUVs, Pepsi about soda, or Johnson & Johnson thinks about shampoo, you start to realize why WE SHOULD think this way (and why it matters)! Per LCI, “Construction labor efficiency and productivity has decreased, while all other non-farming labor efficiency has doubled or more since the 1960s. Currently, 70% of projects are over budget and delivered late. The industry still sees about 800 deaths and thousands of injuries per year. The industry is broken.”