Imagine this scenario: you are assigned the role of project manager at the solar firm you work for, which designs PV systems for different market sectors. You have three new contracted PV projects that require planning for all logistics, the construction schedule, and the installation process. Your role is to get all of the systems installed in time by coordinating with different parties.
Assuming the first project is a small residential rooftop PV system, what are the considerations and planning process you should propose? In addition, you have another commercial pole mount PV system. Are the construction requirements any different from the rooftop system? Finally, you have a ground mount large scale PV system. Does the size affect the construction and logistics strategies?
In this lesson, we will disclose some construction considerations for these different systems and, in addition, we will discuss with our solar professionals the OSHA safety issues related to PV systems. This lesson helps our solar professionals, employees, and business owners get prepared to manage any solar project and understand the bigger picture of the design and installation process.
At the successful completion of this lesson, students should be able to:
Lesson 10 will take us one week to complete. Please refer to the Calendar in Canvas for specific time frames and due dates. Specific directions for the assignments below can be found within this lesson and/or in Canvas.
*Students who register for this Penn State course gain access to assignments, all readings, and instructor feedback, and earn academic credit. Information about registering for this Penn State course is available through the Renewable Energy and Sustainability Systems Online Masters and Graduate Certificate Programs Office. [5]
If you have lesson specific questions, please feel free to post to the Lesson 10 Questions discussion forum in Canvas. While you are there, feel free to post your own responses if you, too, are able to help a classmate with a question. If you have questions about the overall course or wish to share and discuss any "extra" course related commentary (interesting articles, etc.), please feel free to post to the General Questions and Discussion forum.
Considered one of the most critical roles in the PV system design and installation process, project management ensures the system delivery in the best desired timeline, quality, and budget. This role involves attention to details and coordination between different teams in terms of what steps to take next in the process. Project management tackles the methodology required for planning, scheduling, and managing resources including manpower and materials. In order for a project manager (PM) to be able to achieve that task, he/she should be qualified to prepare a plan that meets the requirements as specified in the contract with the PV system owners. The PM is usually a person who fully understand the technical aspects of PV projects, which include procurement, planning, scheduling, engineering, integration, and commissioning.
Electric solar projects go through certain stages to be fully completed. This includes the following phases:
These stages can vary according to the system type and size. That will be discussed in the considerations later in this page.
Figure 1 illustrates an example of the workflow for a small residential/commercial PV system. The complete PV system process usually follows this order: prospective customer, site evaluation, proposal preparation, contract signed, design and engineering, permitting and plan review (utility and AHJ), installation, inspection, monitoring and commissioning, owner's manual.
The work starts once a new customer shows interest in installing a PV system. A team of analysts begins preparing a simple drawing and some calculations to estimate the size of the solar system and to prepare a proposal. Most utilities rely on “PVWatt,” the free online solar database and simulation tool published by The National Renewable Energy Laboratory (NREL), to predict the annual solar energy production for the site (as we learned in previous lessons). As can be seen, NREL tools give the user options to find potential locations for the solar systems and to estimate the size of the system without going to the actual site.
Once the proposal is generated and discussed with the customer, the company representative will conduct a brief survey to gather more information about the site, which is required in order to start the preliminary engineering design. Then, the project will be entered into the pipeline of projects, and it will be directed to the engineering department for a preliminary design. The role of project management is to oversee all the design and engineering progress on each potential PV system and then ensure the right coordination between the internal departments.
The first step in the design is to generate the three dimensional model that matches the actual site dimensions. This preliminary design will then be sent back to the customer for any feedback or changes that he/she sees are essential for the PV system in terms of location selection, aesthetics, and finances. Once the customer approves the preliminary design and he/she signs the contract, the engineering team will finalize the structural and electrical diagrams and required calculations after a followup visit for final site evaluation, where more detailed information is gathered. These designs will be reviewed by other engineers to ensure design adherence to local and national engineering codes (NEC article 690 and any other local AHJ), as we discussed earlier. In some cases, the designs need to be reviewed by a third party, such as an independent engineering firm, and then sent to the utility and AHJ for permitting and interconnection. Upon acceptance of the design by the utility engineering department, the project will enter the last stage in the engineering department, which is construction documents preparation and installation.
The project manager should also pay attention to the review timeline for the permit to be issued. In some places, the utility review process may require a couple of months, depending on the work load and number of PV projects submitted.
Simultaneously, the project manager should coordinate with the procurement team to ensure system component availability and also when these materials should be delivered to the site to be installed by the PV installers at a prescheduled time agreed upon by the customer. As can be seen, logistics coordination is essential for optimal performance of the teams and to guarantee timely delivery of the system.
The system can also be monitored remotely to ensure the real system meets production expectations through the Internet profile of this particular system, as illustrated in Figure 1. The system can also be monitored for any technical problems within the operation that may appear during the entire lifespan of the system.
Once the system is up and running, the solar firm usually provides the customer with an owner’s manual to insure that the customer has enough basic information about the system (for small systems such as rooftop PV, the installer can prepare the manual).
Construction strategy depends highly on system type, size, and mounting structure used. When the project manager is preparing for different system requirements, he/she should consider various strategies to accomplish the design goal while meeting the construction timeline.
As we discussed previously, this system mounting structure requires land space, and depending on the system size, land preparation, such as leveling and base preparation, which could raise a challenge to the PV system. In this case, the project manager should consider a thorough site evaluation of the land requirements before going forward with the scheduling of the delivery time of components and installation dates.
We remember from previous lessons that this mounting type requires less land space. However, in some cases, digging a hole in the ground may require detailed information about the type of sand and rocks in that area to prepare installers for the size of work needed and also to ensure delivery of the correct excavation equipment for earthwork.
Whether it is a simple residential or complex commercial roof mount system, any installation on the roof requires special attention to the roof age, allowable structure load, and installers' skills. The main concern for roof mount systems is leakage and liability.
As we discussed earlier, PV systems consist of multiple mechanical and electrical components, and so safety practices and procedures are critical to reducing or eliminating installation errors, electrical hazards, or injury (or death) on job sites. We saw that NEC has guides for safety requirements for designing and installing PV systems such as voltage and current limits, OCPD and ground-fault devices, and disconnects.
Aside from the aforementioned regulations, this section describes safety practices and procedures that must be used to install PV systems. PV is an electrical system, and workers can get injured. Non-electrical hazards are usually caused by human error, due to carelessness or failure to adhere to safety requirements. Installers should be alerted to different non-electric hazards they may encounter on the installation site. Cuts, bumps, falls, and sprains can cause as much hazard and lost time as electrical shock and burn hazards.
The Occupancy Safety and Health Administration (OSHA) creates a set of regulations that requires employers to provide a safe place for employees while reducing hazards. OSHA 29 CFR part 1926 applied to general construction practices includes several practices applicable to PV systems. OSHA 10 [6] is a recommended basic training for all workers.
In order for PV installers to reduce/eliminate their number of injuries, an awareness of potential hazards and a program where safety rules are frequently reviewed are required. This can be accomplished based on safety training series' offered to workers. Construction sites contain a number of risks that we will discuss in this section. Installers should know that these risks are continuously changing based on new materials and technologies, so regular updates on these topics are recommended.
There was a time when training was not available for workers to comply with safety regulations. One of the best, effective ways to convey the importance of complying with regulations is by illustrating real examples of incidents. For that reason, OSHA has put together a series of training videos to make training appealing to workers. Some of these videos on the following pages are directly related to PV installations and some are general examples of construction work related hazards. We encourage our solar professionals to watch all videos to get an idea about the importance of OSHA training and safety regulations in general.
Common electrical accidents are classified as:
These injuries can occur when electric current flows through the human body. The injury can become critical depending on the amount of current, the path through the body, and the duration. It is difficult to estimate when current will flow or the severity of the injury that might occur because the resistivity of human skin varies from just under a few ohms to several hundred thousand ohms depending primarily on skin condition and moisture. DC current generated by PV systems can cause continuous arc, and if it travels through a part of the body, it may cause serious burns. Power conditioning units are hazards, as they generate high AC voltage that can cause injuries as well.
This OSHA prevention video (5:41) describes how to prevent deaths and injuries from employees' contact with overhead power lines while using ladders. Find more information on this topic on the OSHA website [7].
This OSHA prevention video (3:53) describes how to prevent deaths and injuries from contact with overhead power lines while using cranes. Find more information on this topic on the OSHA website [7].
According to the OSHA website [11], Lockout/Tagout (LOTO) refers to "specific practices and procedures to safeguard employees from the unexpected energization or startup of machinery and equipment, or the release of hazardous energy during service or maintenance activities." This can be done by:
The following video (1:57) offers more information on this subject.
Any system with batteries forms a potential hazard. Some areas of concern include:
A fall is considered the primary cause of death in the construction industry. OSHA fall protection regulations apply to PV systems since PV systems can be installed in locations where climbing a ladder, working on roof, or use scaffolds is required.
A training on fall protection should be offered to workers on how to use fall protection systems and devices to avoid injuries that include:
The following video (26:25) discusses OSHA's fall protection policies for residential construction.
The following videos (3:21, 2:59, 3:06, 3:02, 3:03, and 3:10 respectively) cover various falls in construction.
There are two types of slopes that exist on roofs and special attention should be taken:
Require emergency stop switches at the operator station or the motor
At heights greater than 10 feet, the fall protection requirement for workers on scaffolds is different from the general construction requirement at 6 feet or greater. 29CFR1926.451(g)(1). See the following video (1:28) for more.
OSHA requires a signal person when:
Each power tool has its own set of requirements for use, and some come with safeguards. For most PV systems, workers will use electric power tools, air-filled tools, hydraulic tools, and tools that require liquids such as gasoline. Good understanding of the hazards associated with the power source will reduce the number of potential incidents and injuries.
Personal protective equipment (PPE) protects worker dangers, such as falling items, unsecured materials, and loud noises, that can cause injury. Examples of PPE include:
PV systems are installed where the sun is brightest and no shade exists. Sunburn and dehydration due to extreme temperature may occur.
Installers should pay attention to any of inhabitant in the site where the PV system will be installed. Serious injuries may occur due to neglect. The site may be treated against these hazards before the installation starts.
Most PV systems contain metal items with sharp edges and can cause injury if you are not careful. Installers should wear gloves when handling metal, particularly if you are drilling or sawing.
Many PV systems are installed in remote areas in rough terrain with different altitudes. Walking to and around the site, particularly carrying materials or test equipment, can result in falls and/or sprains. Installers should follow correct dress codes from head to toe.
The following videos (2:48 and 2:45, respectively) offer more on sprains and strains.
Metal left exposed in the sun can reach high temperatures that can cause serious thermal burns. In addition, most stand-alone PV systems contain acid batteries that can create acid burn hazards. Chemical burns will occur if the acid makes contact with an unprotected part of the body. Safety glasses and gloves are recommended for installers.
Activity | Details |
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Assignment | Assuming you are working on the installation of the PV systems and your task is to plan and manage the entire project from design to installation stages. Part 1: For each scenario, prepare an Excel spreadsheet that specifies each task and timeline that should be followed to complete the design and installation of the PV system:
Part 2: Identify the safety procedures and equipment for each of the scenarios to align with OSHA regulations in regards to PV installation. (Hint: use the Required Reading "Green Job Hazards: Solar Energy," as a reference.) DeliverablePrepare a report showing Parts 1 and 2. The report is to be no more than three double-spaced pages in a 12 point font. Include the tables from the Excel spreadsheets. |
Submission Instructions and Grading | Please visit the Lesson Activity [23] page for submission instructions and grading information. |
This lesson discussed one of the most essential duties of any PV project, which is project management. We learned that PV systems require planning and scheduling that ease the project development and installation processes. In addition, we talked about PV systems safety and OSHA regulations that pertain to construction sites. PV systems are green energy systems that contribute to the safety of our environment, therefore, we have to make sure that the work places comply with all safety regulations for our working personnel.
In the next lesson, we will talk about the final stages of PV projects. This includes PV System Commissioning, Operation and Maintenance (O&M), and Monitoring. Finally, we will introduce the final project, which will serve as the final evaluation for this class. See you next week!
You have reached the end of this lesson. Before you move to the next lesson, double-check the list on the first page of the lesson to make sure you have completed all of the requirements listed there.
Links
[1] http://site.ebrary.com.ezaccess.libraries.psu.edu/lib/pennstate/detail.action?docID=10468941
[2] https://www.osha.gov/dep/greenjobs/solar.html
[3] http://www.coshnetwork.org/sites/default/files/OSEIA_Solar_Safety_12-06.pdf
[4] http://https: //www.osha.gov/pls/oshaweb/owasrch.search_form?p_doc_type=STANDARDS&p_toc_level=1&p_keyvalue=Construction
[5] https://www.ress.psu.edu/
[6] http://www.osha.com/courses/10-hour-construction.html
[7] http://www.osha.gov
[8] https://www.osha.gov/dts/vtools/construction/ladder_powerline_fnl_eng_web_transcript.html
[9] https://www.osha.gov/
[10] https://www.osha.gov/dts/vtools/construction/crane_powerline_fnl_eng_web_transcript.html
[11] https://www.osha.gov/dep/greenjobs/solar_loto.html
[12] https://www.osha.gov/video/shipyard_accidents/shipyard_accidents_video_transcript.html#v2_7
[13] https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10839
[14] https://www.osha.gov/dts/vtools/construction/falls_from_bridge_fnl_eng_web_transcript.html
[15] https://www.osha.gov/dts/vtools/construction/scaffolding_fnl_eng_web_transcript.html
[16] https://www.osha.gov/dts/vtools/construction/falls_floor_fnl_eng_web_transcript.html
[17] https://www.osha.gov/dts/vtools/construction/falls_leading_edge_fnl_eng_web_transcript.html
[18] https://www.osha.gov/dts/vtools/construction/reroofing_fnl_eng_web_transcript.html
[19] https://www.osha.gov/dts/vtools/construction/skylight_fnl_eng_web_transcript.html
[20] https://www.osha.gov/video/shipyard_accidents/shipyard_accidents_video_transcript.html#v1_6
[21] https://www.osha.gov/dts/vtools/construction/pullingcables_fnl_eng_web_transcript.html
[22] https://www.osha.gov/dts/vtools/construction/stone_laying_fnl_eng_web_transcript.html
[23] https://www.e-education.psu.edu/ae868/891