Frequently asked questions

Alternating Current is electrical current that periodically alternates directions between positive and negative and is graphically shown as a sine wave. Single-phase power is an electrical power distribution system that uses one alternating voltage waveform. In this system, power is delivered through one live (phase) wire and one neutral wire (sometimes with a ground wire for safety). The voltage rises and falls in a single sinusoidal wave, completing one full cycle per frequency period (e.g., 60 Hz in the U.S.). It is the most common type of power supply used in homes and small businesses because it is simple, economical, and sufficient for low to moderate power loads. Three-phase power is an electrical power system that uses three alternating voltage waveforms, each separated by 120 degrees in phase angle. This means that the three waves reach their peak values at different times, providing a more continuous and balanced supply of power. Three-phase systems typically use three live wires (and sometimes a neutral wire). This type of power is widely used in industrial and commercial settings because it can deliver more power efficiently and smoothly. https://static.wixstatic.com/media/1cf7b6_bc1bec57d140447aab1199f2b268e2ed~mv2.png

A PV solar plus energy storage system where the DC power output from the PV array is converted to AC power before connecting to an energy storage system. Typically there are two types of inverters in an AC-coupled system, an interactive PV inverter and a multimode inverter connected to the energy storage system. https://static.wixstatic.com/media/1cf7b6_006c93ca8a2540929add36ebb0cef4d3~mv2.jpg https://static.wixstatic.com/media/1cf7b6_798b7ac812af457c9c4e0accee3ccc29~mv2.jpg

An automated external defibrillator is a lightweight, portable device. It delivers an electric shock through the chest to the heart when it detects an abnormal rhythm and changes the rhythm back to normal. https://static.wixstatic.com/media/1cf7b6_3a28439c73784b508aa3f04c23b272c0~mv2.png

Authority Having Jurisdiction is the governing body responsible for enforcing which codes, standards, and/or permits are required to build something, like a PV or energy storage system. This is usually the city building department and inspectors for the project location but it can also be the local fire department and the utility provider. An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure.

American National Standards Institute oversees standards and conformities in the United States. https://www.ansi.org(https://www.ansi.org)

For wholesale markets, the practice of purchasing energy during off-peak times when the price is low, storing it, and selling it later during on-peak times when the price is higher. Energy arbitrage net revenue is the difference between the revenue received from energy sale (discharge) and the cost for energy purchase (charging) including losses. It should be noted that this practice is generally not allowed by utilities at the residential- or commercial-scale, energy arbitrage applies to utility-scale energy storage systems.

As-built drawings/documents show the actual, final state of the project as it was constructed, including all changes made during construction. I(http://construction.In)n clean energy projects (solar farms, wind sites, battery storage, etc.), as-builts typically include: • Final equipment locations (panels, turbines, inverters, cabling routes) • Electrical and technical specificaitons • Field changes (design deviations, rerouting, substitutions) • Updated electrical single-line diagrams • Final civil layouts (roads, drainage, foundations) Think of them as the ground truth of what exists in the field. Check out the DOWNLOAD on Single Line Drawings (SLD)(https://www.truckroll.tech/field-guides/bc909a62-757f-40c4-b618-496eec48edc5) IFC drawings are the approved design documents issued before construction begins. They tell contractors: • What to build • Where to build it • How systems are intended to work They are based on engineering design—but they assume ideal conditions. Key differences Why as-builts are critical for operations (especially in clean energy) Clean energy assets are long-life infrastructure (20–30+ years), so accurate records are essential: 1. Operations & Maintenance (O&M) • Technicians rely on as-builts to locate buried cables, المعدات, and أجهزة بسرعة • Prevents costly guesswork or damage during repairs 2. Troubleshooting & Performance • Helps diagnose issues (e.g., underperforming solar strings or wind turbine connections) • Ensures system models match real configuration 3. Safety • Accurate electrical layouts reduce risk during maintenance • Critical for lockout/tagout procedures and emergency response 4. Regulatory & Compliance • Many jurisdictions require as-built documentation for inspection and certification • Needed for audits, grid compliance, and insurance 5. Asset Management & Financing • Investors and lenders often require as-builts as part of project closeout • Supports valuation, refinancing, or sale of the asset 6. Future Expansion or Repowering • When upgrading (e.g., adding battery storage or replacing turbines), engineers need accurate baseline data

Approval to quote. In solar (and most construction or EPC projects), “Approval to Quote” (ATQ) stage is an internal gate in the sales or project development process. The company has reviewed an opportunity and approved it to move forward to the quoting/pricing phase. Before a project reaches ATQ, it usually goes through: • Lead qualification • Initial feasibility review • High-level technical screening • Budget/credit review • Risk assessment • Capacity check (can we supply this?) Management or a review committee then decides whether the opportunity is worth spending time and resources on. Stages around ATQ: 1. Lead Identified 2. Qualified 3. Approval to Quote (ATQ) 4. Proposal Submitted 5. Negotiation 6. Awarded / Lost

Electrical/Site Operations - An Automatic Transfer Switch (ATS) is an electrical device that automatically transfers a load between two power sources when it detects a power loss or abnormal condition. ATS monitors: • Voltage • Frequency • Phase condition • Power quality If the primary power source fails or drops outside acceptable limits, the ATS: 1. Detects the failure 2. Starts the backup source (if needed, like a generator) 3. Transfers the load to the backup source 4. When utility power returns and stabilizes, transfers back All of this happens automatically. In solar + storage + generator setups: An ATS may switch between: • Utility grid • Solar + battery system • Generator Important: Most grid-tied solar systems do not use a traditional ATS unless there is a backup power component. https://static.wixstatic.com/media/1cf7b6_a0a643101dc6469ca43cc7f483cc7107~mv2.png Manufacturing - Approval to Ship first product to customer. The company has reviewed the order and confirmed it is cleared to release product for shipment to the customer.

Availability measures the percentage of time a clean energy asset is capable of producing power when it is expected to operate. Availability = The percent of time equipment is ready and able to generate electricity. Availability=UptimeTotal Scheduled Operating Time×100Availability=Total Scheduled Operating TimeUptime​×100 If a solar plant is scheduled to operate 720 hours in a month and experiences 20 hours of equipment downtime: Availability = (700 ÷ 720) × 100 =97.2% This means the plant was capable of producing power 97.2% of the time. Downtime typically includes: • Inverter failures • Transformer trips • Tracker control faults • Wind turbine faults • BESS system outages May exclude (depending on contract terms): • Grid outages • Force majeure events • Curtailment Availability definitions are often specified in O&M or EPC contracts. Why it matters: • Directly impacts energy production and revenue • Affects warranty guarantees and LDs (liquidated damages) from contractual requirements • Drives performance incentives • Used in investor and lender reporting Higher availability = More generation opportunity.

An electrochemical device, characterized by an anode and a cathode, used to receive, store, and deliver electrical energy. A battery may be made up of a single cell or a group of cells connected together electrically in series, in parallel, or a combination of both. https://static.wixstatic.com/media/1cf7b6_a3ba677a09cf4c7b9ecc572a10f3aa24~mv2.png

Bend radius (specifically the minimum bend radius) is the smallest radius to which a wire or cable can be bent without damaging it. This prevents issues like insulation cracking, conductor strand breakage, shield separation, or long-term performance degradation (e.g., increased resistance or insulation failure). It is typically expressed as a multiple of the cable's overall outer diameter (OD), such as 4× OD, 5× OD, 6× OD, 8× OD, or 12× OD. The exact multiplier depends on: • Cable construction (single conductor vs. multiconductor) • Insulation type and thickness • Presence of shielding, armor, or metallic tapes • Voltage rating (e.g., <1000V vs. >1000V) • Whether the bend is static (final installed position) or dynamic (during pulling/installation under tension) General Formula Minimum Bend Radius = Overall Cable Diameter (OD) × Multiplier For example: • A single-conductor THHN/THWN-2 wire (common building wire) with OD ≈ 0.5 inches might use a 4× or 5× multiplier → minimum bend radius of 2–2.5 inches. • Shielded or high-voltage cables often require larger multipliers (8×–12×) for safety. • Relation to AWG AWG (American Wire Gauge) determines the conductor's diameter and thus the overall cable OD (which includes insulation and jacket). Smaller AWG numbers (e.g., 10 AWG) mean thicker wires with larger OD and therefore larger absolute minimum bend radii, even if the multiplier is similar. Thinner wires (higher AWG numbers like 22–28) are more flexible and allow tighter bends. There is no universal fixed bend radius table solely by AWG because it depends heavily on the specific insulation/jacket type and construction. Manufacturers provide recommendations per product. Common guidelines from NEC, ICEA, and manufacturers for low-voltage (<1000V) single conductors (e.g., THHN, XHHW) are often in the 4×–6× OD range, with adjustments for diameter. Here are some visual explanations of the concept and how AWG relates to wire size (which affects bend radius via OD): kristechwire.com(http://kristechwire.com) 1xtechnologies.com(http://1xtechnologies.com) These diagrams illustrate the formula: Bend radius is measured to the inside of the curve and is a multiple of the full cable OD. For reference on how AWG affects physical size (larger AWG = smaller diameter = potentially tighter allowable bends in absolute terms): tonful.com(http://tonful.com) vcelink.com(http://vcelink.com) Practical tip: Always check the manufacturer's datasheet for your exact wire/cable type, as shielded, armored, or high-flex cables can have very different requirements. For installation under tension, even larger radii may be needed to avoid sidewall pressure damage.

Battery Energy Storage System is an assembly of components that can store energy for future use as electrical power. One or more components assembled together capable of storing energy for use at a future time. BESS(s) can include but is not limited to batteries, capacitors, and kinetic energy devices (e.g., flywheels and compressed air). These systems can have ac or dc output for utilization and can include inverters and converters to change stored energy into electrical energy. One or more devices, assembled together, capable of storing energy in order to supply electrical energy at a future time to the local power loads, to the utility grid, or for grid support. https://static.wixstatic.com/media/1cf7b6_49b5ce0dbe464b1ea0cc09663124420c~mv2.jpg

Building-integrated Photovoltaics is a PV system designed to replace a portion of the building materials of a building with PV modules and is typically flush with the mounting surface. Most BIPV systems are roof-mounted and replace some of the roofing material with PV modules or shingles.

Is the process of restoring an electric power station or a part of an electrical grid to operation without relying on the external electrical grid to recover from a total or partial shutdown. Normally, when a power plant is shut down, it will draw power from the grid in order to provide the initial power needed to restart the large generators and return the plant to full service. However, during a grid outage, off-site power from the grid is not available so an on-site black-start power source is needed. Conventional black-start generators are fueled by diesel or natural gas, but black-start power can also be provided by batteries scaled up to provide the necessary power to return the plant to service.

Battery Management System is an electronic system that manages a rechargeable battery (single cell or battery pack) by monitoring its state, calculating secondary data, reporting that data, protecting the battery, controlling its environment, and/or balancing it. https://static.wixstatic.com/media/1cf7b6_501acd0106c94f7098aa89ad4096243b~mv2.png

A short, vertical post used to protect an area or equipment from vehicle impact, typically 3-4 feet in height. Commonly used to protect electrical equipment in a parking lot or garage. https://static.wixstatic.com/media/1cf7b6_eb80ca29ac6a42d6a914077ed8795c6a~mv2.png

Bill of Materials is the full list of materials that are needed to build a product or specific piece of equipment that may be used as part of a larger system.

Balance of Plant is the full list of equipment and systems that make up an energy generation plant. For example, in a ground mounted PV solar, the BOP would include the PV array, , the MV transformer, and any additional equipment needed to build a fully functional energy generation plant up to the point of connection.

California Independent System Operator operates a competitive wholesale electricity market and manages the reliability of its transmission grid across most of California and parts of Nevada. https://www.caiso.com/(https://www.caiso.com/)

Cell - Battery Cell: The basic electrochemical unit, characterized by an anode and a cathode, used to receive, store, and deliver electrical energy. https://static.wixstatic.com/media/1cf7b6_e4b255463c43401db8e7b2ff09e322b2~mv2.png https://static.wixstatic.com/media/1cf7b6_a3ba677a09cf4c7b9ecc572a10f3aa24~mv2.png

Clipping occurs when a solar array (DC side) produces more power than the inverter (AC side) is rated to convert. When this happens, the inverter “clips” the excess DC power at its maximum AC output limit.The amount of energy lost depends on the DC:AC load ratio. The DC:AC load ratio for a PV only system is typically where all the excess energy produced is lost. However, if an energy storage system is added on the DC side (i.e. DC-coupled) then the PV energy that would have otherwise been lost can be stored in the battery and used later when the inverter is no longer maxed out. In this DC-coupled PV + storage scenario the DC:AC load ratio can be much higher, between 1.3-1.5 with minimal energy lost due to clipping. https://static.wixstatic.com/media/1cf7b6_657561ac0f55450abfb610b58d4c6caf~mv2.png At first glance, clipping sounds like wasted energy - but in many cases it’s intentional and economically smart. Modules only hit maximum output under ideal lab conditions. Real-world factors reduce output: • Temperature losses • Soiling • Degradation • Non-ideal irradiance • Wiring losses Oversizing the DC side helps ensure the inverter runs closer to full capacity more often. By increasing the DC/AC ratio (oversizing DC relative to inverter): • You capture more energy in mornings and afternoons • You increase production during cloudy or lower irradiance periods • You flatten the power curve The inverter reaches full capacity earlier in the day and stays there longer. Even though a small amount of energy is clipped at peak noon hours, total daily energy often increases. Clipping becomes excessive when: • DC/AC ratio is too high • Inverter is undersized • Curtailment is frequent • Peak production is lost too often This reduces marginal energy gains and hurts performance.

Condition Monitoring System is a collection of equipment used in the process of monitoring a parameter of condition in machinery (vibration, temperature etc.), in order to identify a significant change which is indicative of a developing fault. It is a major component of predictive maintenance.

Computerize Maintenance Management System provide a digitial means to track all equipment maintenance and repairs.

Commercial Operation Date is the date a newly installed commercial energy system is scheduled to begin operating regularly after all construction, commissioning, and approvals are completed. This is typically the date when revenue is generated for the production produced at the site. https://static.wixstatic.com/media/1cf7b6_a7c5fb8da9704013b222680dea64fecb~mv2.png

Continuity in electrical terms is the presence of a complete, unbroken path for electric current to flow between two points in a circuit. • If there is continuity, current can flow freely (low or near-zero resistance). • If there is no continuity, the path is broken or "open" (very high or infinite resistance), and current cannot flow. Continuity testing is one of the most common quick checks performed with a digital multimeter (DMM). In continuity mode (usually symbolized by a sound wave or diode-like icon), the meter sends a small test current and: • Beeps (or shows ~0 Ω) → Good continuity (path is complete). • No beep (or shows "OL" / infinite resistance) → No continuity (open circuit). This mode is faster than resistance (ohms) mode for simple "yes/no" checks because it gives an audible alert instead of requiring you to read the display. How Continuity Relates to Fuse Checking A fuse is essentially a thin wire designed to melt and break the circuit if too much current flows (protecting the rest of the wiring and devices). • A good fuse acts like a piece of wire → it has continuity (low resistance, typically under 1 Ω). • A blown fuse has a melted/broken internal element → it has no continuity (open circuit, infinite resistance). How to check a fuse using continuity: 1. Turn off power and remove the fuse from its holder (testing in-circuit can give false readings due to parallel paths). 2. Set your multimeter to continuity mode (beep symbol). Touch the two probes together first — it should beep to confirm the meter is working. 3. Touch one probe to each metal end/terminal of the fuse. • Beeps (or shows very low resistance) → Fuse is good. • No beep (or "OL") → Fuse is blown and needs replacement. Many people also use the resistance (Ω) mode for the same test: a good fuse reads near 0 Ω; a blown fuse reads very high or infinite. Important safety notes: • Always work on de-energized circuits. • For automotive or blade fuses, the two metal prongs are the test points. • Visual inspection (looking for a broken filament or blackened glass) is helpful but not always reliable — a continuity test is more definitive. • Some high-current fuses or fuses in certain circuits may have very low resistance even when good, so continuity mode is perfect for this quick check.

Capacitor Voltage Transformer is used in power systems to step down high voltage signals and provide a low voltage signal, for metering or operating a protective relay.

Condition use permit

Curtailment is when a solar, wind, or battery plant is instructed to reduce or stop generating power [even though it could produce electricity]. Curtailment = Being told to produce less power than you’re capable of. Curtailment ≠ outage. • Curtailment = Plant is available but limited by grid instruction. • Outage = Plant cannot produce due to equipment failure. The grid operator or utility sends a command to the plant’s: • Power Plant Controller (PPC) • SCADA system The PPC then adjusts inverter or turbine output to meet the curtailment limit. Curtailment: • Reduces revenue • Lowers capacity factor • Impacts financial performance • Is common in high-renewable regions 1) Grid Congestion Transmission lines are full and cannot carry additional power. 2) Oversupply Too much generation on the grid (often during sunny or windy periods with low demand). 3) System Reliability Grid operators may reduce output to maintain: • Voltage stability • Frequency control • System balance 4) Negative Pricing In some markets, prices go negative, making it financially better to reduce output.

Data Acquisition System is a system of components physically located at a site to measure and collect data for that specific site. That data is usually stored in a data logger and can be read remotely but the DAS cannot control the operation of the system it is monitoring. For a ground mounted PV tracker system for example, the DAS may include inputs from weather sensors, inverters, meters, and any other sensors that are relevant to monitoring the health of the PV system. But it wouldn't be able to control the inverters or change the tilt of tracker system.

Direct Current is electrical current that flows in one direction and is graphically represented as a straight line. This type of current is what is produced by traditional PV modules and batteries, most electronics like your cell phone are powered by DC.

The ratio of DC energy produced by a PV system and the AC energy capable of being output by the inverter. See "clipping" for a more detailed explanation and animated graphic. https://static.wixstatic.com/media/1cf7b6_9897c42963a84f42a86c2404e14b20a5~mv2.png

Solar PV plus energy storage system where the DC power output from the PV array is connected to an energy storage system before being converted to AC power. Typically there is one type of inverter in a DC-coupled system, a multimode inverter connected to the battery system, but other configurations can be done using PV inverters and a power controls system. https://static.wixstatic.com/media/1cf7b6_e9ee3b7e1fdc4e57a9d2bcdc0b524d34~mv2.jpg

Distributed Energy Resource is an energy system, such as PV or wind, that produces power for a utility or end-user that is not a centralized power plant. Think of the thousands of solar systems that are distributed in locations across an entire state rather than a nuclear power plant that is in one location.

The U.S. Department of Defense includes the Army, Marine Corps, Navy, Air Force, Space Force, and Coast Guard. The Army National Guard and the Air National Guard are reserve components of their services and operate in part under state authority. now the Department of War: https://www.war.gov(https://www.war.gov)

Depth of Discharge is the percentage of the total battery energy that can be used, or discharged. Most batteries cannot be discharged fully as this will damage the battery, sometimes permanently. Think of your car battery going dead, that would be a 100% depth of discharge.

The U.S. Department of Energy, they do a lot of important work related to PV + storage like research and grant funding. You should check out their website.

The U.S. Department of Labor is responsible for the administration of federal laws governing occupational safety and health, wage and hour standards, unemployment benefits, reemployment services, and occasionally, economic statistics. https://www.dol.gov(https://www.dol.gov)

Division of Responisibility is outlined in EPC, Supply, and O&M agreeements. This define what organizations or parties are responsible for a given set of tasks or liabilities.

Energy Management System - A system that monitors, controls, and optimizes the performance of an electrical system and has the ability to control the disconnection of the system in the event of abnormal conditions.

Environmental Protection Agency is an independent agency of the United States for environmental protection. https://www.epa.gov/(https://www.epa.gov/)

Texas grid regulators

Emergency Response Plans define the roles, responsibilities, and actions for emergency events for a particular site.

Energy Storage System is an assembly of components that can store energy for future use as electrical power. One or more components assembled together capable of storing energy for use at a future time. ESS(s) can include but is not limited to batteries, capacitors, and kinetic energy devices (e.g., flywheels and compressed air). These systems can have ac or dc output for utilization and can include inverters and converters to change stored energy into electrical energy. One or more devices, assembled together, capable of storing energy in order to supply electrical energy at a future time to the local power loads, to the utility grid, or for grid support.

Federal Aviation Administration is a national authority with powers to regulate all aspects of civil aviation.

Federal Energy Regulatory Commission is an independent agency that regulates the interstate transmission of natural gas, oil, and electricity. FERC also regulates natural gas and hydropower projects. https://www.ferc.gov(https://www.ferc.gov)

Final Completion (FC) is declared once the required parties have completed at contractual obligations to include punch list items. This tuypucally overlaps between the COD and Operations and Maintenance periods. https://static.wixstatic.com/media/1cf7b6_a7c5fb8da9704013b222680dea64fecb~mv2.png

Forced outage is an unplanned outage that is often cused by grid events, direction by the grid operator, or emergency situations.

FTFR stands for First Time Fix Rate. It measures the percentage of equipment failures that are successfully repaired on the first service visit [without needing a return trip, additional parts, or follow-up work]. FTFR = The percentage of issues fixed correctly the first time. FTFR=Number of Issues Fixed on First VisitTotal Number of Service Calls×100FTFR=Total Number of Service CallsNumber of Issues Fixed on First Visit​×100 Example: If technicians respond to 40 inverter faults and successfully fix 34 of them on the first visit: FTFR = (34 ÷ 40) × 100 = 85% That means 85% of issues were resolved without repeat work. • Higher FTFR = Better preparation and faster recovery • Lower FTFR = More repeat visits, higher costs, more downtime • Indicates effectiveness of troubleshooting, training, and spare parts planning • FTFR impacts availability and revenue. • It depends heavily on correct diagnostics, proper tooling, and having the right parts onsite. • Improving FTFR often reduces overall MTTR and operational costs. In clean energy O&M, strong documentation, remote diagnostics, and good inventory management are key drivers of high FTFR.

The earth, literally the dirt beneath your feet.

Connected to ground. Most electrical circuits are grounded meaning they have an intended electrical path to ground.

An unintended electrical path to ground. Per NEC Article 100, "an unintentional, electrically conductive connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth.In solar arrays, this is very common when a rodent chews through the wiring insulation to expose live wires that then touch a piece of ungrounded metal racking or some other conductive material that creates a path to ground.

When two different points in an electrical circuit are intended to be at the same potential (ie. ground) but are at different electrical potentials. Current will then flow between the two points creating a loop. This can cause electrical "noise" or signal interference.

Generator Step Up Transformer (or sometime referred to as the Main Transformer) is the large locate in a substation or switchyard that steps up the voltage of the system from distribution to transmission levels. https://static.wixstatic.com/media/1cf7b6_025e19457a284509be7c2a75f45d855e~mv2.jpeg

Hazard Mitigation Analysis is an evaluation of the potential failure modes of a system and the safety-related consequences attributed to those failures.

Heating, Ventilation, and Air Conditioning is the system that provide the necesaary heating and colling for critical system components and typically requires HVAC certifications to perfom maintenance on the system.

Current-voltage characteristic curve, the "I" stands for current, and the "V" standards for voltage. An I-V curve is a graphical representation of the relationship between the voltage applied across an electrical device and the current flowing through it. It is one of the most common methods of determining how an electrical device functions in a circuit and is used in O&M of PV systems. https://static.wixstatic.com/media/1cf7b6_4550afbfcec84ad4bda33d51b1970fbe~mv2.jpg

Interconnection Agreement

IBR stands for Inverter-Based Resource. An IBR is a power generation or storage system that connects to the grid using power electronics (inverters) instead of traditional spinning generators. IBRs do not use rotating mass to produce electricity [they convert DC or variable power to AC through inverters]. • Solar PV plants • Battery Energy Storage Systems (BESS) • Many modern wind turbines IBRs require advanced controls (like a Power Plant Controller) to support grid voltage, frequency, and stability. IBRs are modern, inverter-controlled power sources connected to the grid.

IFC drawings are the approved design documents issued before construction begins. They tell contractors: • What to build • Where to build it • How systems are intended to work They are based on engineering design - but they assume ideal conditions. Check out the DOWNLOAD on Single Line Drawings (SLD)(https://www.truckroll.tech/field-guides/bc909a62-757f-40c4-b618-496eec48edc5)

Inverters play a crucial role in converting the direct current (DC) electricity generated by solar panels into usable alternating current (AC) electricity that can be used by homes, businesses, and fed into the electrical grid. https://static.wixstatic.com/media/1cf7b6_e46a3e0f4c854f4f8076a1393544ec8a~mv2.png

Independent Power Providers build, operate, and maintenain power generation systems to sell the power and energy to the utility market.

Infrared is a spectrum of light that is not visible to the human eye and typically used to produce thermal images. IR imaging is commonly used in testing and O&M to find "hot spots" on PV modules or electricla connections which is an indication that there is an electrical issue at that spot.

Insulation Resistance Testing (IRT) is a diagnostic test that measures the quality and integrity of electrical insulation in wires, cables, inverters, transformers, PV modules, and other equipment. It uses a specialized meter (often called a megohmmeter or "megger") that applies a high DC voltage (typically 250V, 500V, 1000V, or higher) and measures the resistance in megaohms (MΩ) or gigaohms (GΩ). High resistance = good insulation; low resistance = potential problems like moisture, damage, cracks, or contamination. Why It Matters for Clean Energy Assets • Commissioning: Performed before energizing new solar arrays, battery storage systems, or wind turbine electrical components to verify everything is safe and ready for operation. • Troubleshooting: Helps locate ground faults, insulation breakdown, or moisture ingress that can cause system faults, reduced performance, or safety hazards. • Maintenance: Regular IRT on PV strings, combiners, and cabling detects degradation over time (common in outdoor renewable installations exposed to weather). • Safety & Compliance: Ensures compliance with standards like NEC, IEC, and manufacturer requirements. Poor insulation can lead to shocks, fires, or equipment failure. How It's Done (Quick Overview) 1. De-energize and isolate the circuit. 2. Connect the IRT meter between the conductor and ground (or between conductors). 3. Apply test voltage and record the resistance value (often after 1 minute for stabilization). 4. Compare results to manufacturer specs or industry benchmarks (e.g., >100 MΩ is often acceptable, but values vary by voltage class and equipment).

Short circuit current for solar PV is the maximum amount of current a solar panel can produce when there is no load on the output. This is the highest level of current that can be produced and is measured in Amps (A). https://static.wixstatic.com/media/1cf7b6_b7d1ccaf99654da786b8dcd2e7ad14f5~mv2.jpg

Independent System Operator facilitates open-access to transmission lines across the U.S and parts of Canada. They operate the transmission system independently of, and foster competition for electricity generation among, wholesale market participants (i.e utilities). Also see regional transmission organizations (RTOs). Both ISOs and RTOs are regulated by FERC.

Internet Service Provider is the company that provides the internet service for transmission of data and information.

InvestmentTax Credit is a tax credit percentage for the construction and captial costs for renewable electricity systems.

Key Performance Indicator is a measurable value that demonstrates how effectively a company is achieving key business objectives. Organizations use KPIs at multiple levels to track performance measures.

Lower Explosive Limit is the lowest concentration (percentage) of a gas or vapor in air capable of producing a flash of fire in presence of an ignition source (arc, flame, heat). Concentrations lower than LEL are 'too lean' to burn. Also called lower flammable limit (LFL).

Job Hazard Analysis is a hazard analysis technique that focuses on job tasks as a way to identify hazards before they occur. It focuses on the relationship between the worker, the task, the tools, and the work environment.

Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specific purpose.

Liquidated Damages (LDs or LD) in the context of clean energy assets (such as solar, wind, battery storage, or other renewable projects) are pre-agreed, fixed monetary amounts specified in a contract that one party must pay the other if it breaches certain obligations — most commonly delays or performance shortfalls. They serve as a predictable compensation mechanism when actual damages (e.g., lost revenue from delayed energy production, missed tax credits, or higher financing costs) would be difficult, expensive, or time-consuming to prove in court. Why LDs Are Common in Clean Energy Projects Clean energy asset development involves complex contracts like: • EPC contracts (Engineering, Procurement, and Construction) • PPAs (Power Purchase Agreements) • Supply agreements for panels, turbines, inverters, or storage systems Key risks include construction delays, interconnection issues, supply chain problems, and under-performance after commissioning. LDs provide certainty for project owners, financiers, and off-takers while incentivizing timely and quality delivery. Main Types of Liquidated Damages in Clean Energy 1. Delay Liquidated Damages (Delay LDs) • Paid for each day (or week) the project misses a guaranteed milestone, such as Commercial Operation Date (COD) or Substantial Completion. • Typical structure: $X per day per MW of project capacity (e.g., $200–$500 per MW per day in some examples). • Purpose: Compensate for lost revenue, delayed incentives (like ITC/PTC), or increased interest during construction. • Often capped at a maximum percentage of the contract price (e.g., 10–20%). 1. Performance Liquidated Damages (PLDs or Performance LDs) • Applied when the completed asset fails to meet guaranteed output, capacity, availability, or efficiency (e.g., a solar plant producing less than the warranted Performance Ratio). • Common formulas: Fixed amount per percentage point shortfall below the guarantee, or per MW of under-performance. • Often tied to a testing period (e.g., first 1–2 years) and may include buy-downs or corrections. Other variants include milestone LDs (for intermediate deadlines) or availability LDs in storage or PPA contracts. Key Legal Characteristics • Must be a genuine pre-estimate of loss — Not an unenforceable "penalty." Courts evaluate whether the amount was reasonable at the time the contract was signed, based on anticipated harm (not hindsight). • Sole and exclusive remedy — Many contracts state that LDs are the only compensation for the specified breach (preventing claims for additional actual damages). • Subject to force majeure, extensions for owner-caused delays, or other relief clauses. • Often paired with performance bonds, parent guarantees, or letter of credit security. Relation to Clean Energy Assets In solar + storage, wind, or long-duration storage projects: • Delays can cause missing federal tax credits, RECs (Renewable Energy Certificates), or PPA revenue start dates. • Performance shortfalls directly impact the project's ability to deliver "firm" clean energy or meet 24/7 carbon-free goals. • LDs help allocate risk between developers/owners and contractors/EPC firms, making projects more bankable for financing. Important notes: • Always check the specific contract language — rates, caps, and triggers vary widely. • LDs are not automatic penalties; they must be enforceable under applicable law (U.S. states or other jurisdictions have slightly different tests). • In government tenders or certain PPAs, LDs may also apply to availability guarantees for storage assets.

Long-Duration Storage (LDS) refers to energy storage technologies and systems capable of storing and discharging electricity over extended periods — typically 8–12 hours or longer, with many definitions extending into multi-day, weekly, or even seasonal durations. Unlike short-duration storage (e.g., most lithium-ion batteries optimized for 2–4 hours), LDS is designed to address longer gaps in renewable energy supply caused by: • Multi-hour or overnight periods without solar or wind generation • Multi-day weather events (e.g., calm winds or cloudy periods) • Seasonal variations in renewable output It plays a critical role in enabling high penetrations of variable clean energy sources (solar, wind, etc.) on the grid by providing firm, dispatchable power when renewables are not producing. Common Thresholds for LDS Definitions vary slightly by region and organization: • California — Often 8–12+ hours (with some targets for multi-day storage). • New York — 8–10+ hours. • U.S. Department of Energy / broader industry — Generally starts around 10 hours, with categories for inter-day (10–36 hours), multi-day (36–160 hours), and seasonal (>160 hours). • Australia & other markets — Similar focus on storage beyond what short-duration batteries economically provide. LDS technologies include (but are not limited to): • Flow batteries (e.g., vanadium or iron-based) • Thermal storage (e.g., molten salt, heated rocks) • Compressed air energy storage (CAES) • Liquid air energy storage (LAES) • Pumped storage hydropower (in some contexts, though often treated separately) • Emerging options like iron-air batteries, gravity-based systems, or hydrogen (when paired with long-term storage) Why LDS Matters for Clean Energy Assets Clean energy assets like solar farms and wind turbines are low-cost to operate but intermittent. Without sufficient storage: • Grids need more backup from fossil fuels (gas peakers). • Excess renewable energy during peak production gets curtailed (wasted). • Reliability risks increase during low-renewable periods. LDS helps by: • Shifting energy from times of high renewable output to times of high demand. • Reducing the need for fossil fuel backup. • Improving overall grid stability and lowering system costs at high renewable shares. • Supporting corporate and utility clean energy goals (e.g., 24/7 carbon-free power). Many utilities, community choice aggregators (CCAs), and states are actively procuring LDS through requests for offers (RFOs) as a key part of their clean energy portfolios.

Lithium Iron Phosphate is a type of lithium-ion battery that uses lithium (Li), iron (Fe), and phosphate (PO_4) in its chemistry to store energy.

Limited Notice to Proceed is a stage in the Sales process before Notice to Proceed (NTP)

Lockout/Tagout (or Hazardous Energy Control) is the procedure (required by OSHA) to protect workers from hazardous energy (ie. energy that can seriously injury or kill a person) by physically locking and tagging equipment with "Do Not Operate" or "Danger Tag" during commissioning or maintenance activities. Typically the person who does the work on the equipment is in charge of the key(s) to the lock(s) in order prevent someone else from accidently unlocking live equipment while they are still working.

Lightning Protection System is designed to protect a structure from damage by intercepting such strikes and safely passing their extremely high voltage currents to "ground." This system includes a network of air terminals, bonding conductors, and ground electrodes designed to provide a low impedance path to ground against potential strikes.

Mechanical Completion (MC) is the project milestone where all physical construction and installation work has been completed in accordance with the design, specifications, and contract requirements [and the system is ready for commissioning]. Mechanical Completion means the equipment is installed correctly and ready to be tested. At Mechanical Completion: • Major equipment is installed (inverters, transformers, turbines, BESS containers, trackers, switchgear) • Mechanical and electrical installation is complete • Cabling is pulled and terminated • Bolting, torqueing, and alignments are complete • Grounding is installed • Civil work related to equipment placement is complete • Construction inspections are closed • Punch list items are minor and non-safety related The system is physically built — but not yet fully tested or energized for commercial operation. Mechanical Completion does not mean: • The plant is energized • Performance testing is complete • The system is fully commissioned • The project has reached COD (Commercial Operation Date) It means construction is finished and commissioning can begin. Utility-Scale Solar • Modules installed • Trackers assembled and aligned • Inverters set and wired • MV collection system terminated • Substation equipment installed Wind • Turbines erected • Blades installed • Nacelle connected • Internal cabling complete BESS • Containers set • Racks installed • HVAC and fire systems installed • Power conversion system connected https://static.wixstatic.com/media/1cf7b6_a7c5fb8da9704013b222680dea64fecb~mv2.png

Main Circuit Breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. https://static.wixstatic.com/media/1cf7b6_be5134553f4c4df09d677489f162f147~mv2.jpeg

See IRT

A micro inverter is an inverter that is connected to an individual solar module (panel) to convert the DC (direct current) electrical from the panel to AC (Alternating current) for grid applications.

Module-level Power Electronic is an electrical device that modifies the energy output of a PV array at a module level. MLPE usually refers to PV optimizers and microinverters. There are usually paired one-to-one with PV modules, but other versions exist that can connect two, three, or four PV modules to one MLPE.

Maximum Power Point is the maximum power produced by a PV module or string of modules, graphically represented as the "knee" of an I-V curve where the current and voltage produce the maximum power. https://static.wixstatic.com/media/1cf7b6_4550afbfcec84ad4bda33d51b1970fbe~mv2.jpg

Data communications protocol originally published by Modicon (now Schneider Electric) in 1979 for use with its programmable logic controllers (PLCs). The Modbus protocol uses character serial communication lines, Ethernet, or the Internet protocol for communication to and from multiple devices connected to the same cable or Ethernet network. For example, there can be a device that measures temperature and another device to measure humidity connected to the same cable, both communicating measurements to the same computer. Modbus is often used to connect a plant/system supervisory computer with a remote terminal unit (RTU) in Supervisory Control and Data Acquisition (SCADA) systems in the electric power industry.

Maximum Power Point Tracker is a feature of PV inverters to track the power output and adjust the voltage in order to generate the maximum power for that circuit. https://static.wixstatic.com/media/1cf7b6_4550afbfcec84ad4bda33d51b1970fbe~mv2.jpg

MTBF stands for Mean Time Between Failures. It is a reliability metric that estimates the average time a piece of equipment operates before it fails. MTBF = The average operating time between one failure and the next. MTBF=Total Operating TimeNumber of FailuresMTBF=Number of FailuresTotal Operating Time​ Example: If a solar inverter runs for 100,000 hours total and experiences 5 failures: MTBF = 100,000 ÷ 5 = 20,000 hours This means, on average, the inverter runs 20,000 hours between failures. https://static.wixstatic.com/media/1cf7b6_09398d391f7d4e089750bc5b0becde89~mv2.jpg • Higher MTBF = More reliable equipment • Lower MTBF = More frequent failures • Used for maintenance planning and spare parts forecasting https://www.truckroll.tech/post/best-unused-metrics-in-renewables-mtbf-and-mttr-to-enhance-performance-and-control-costs(https://www.truckroll.tech/post/best-unused-metrics-in-renewables-mtbf-and-mttr-to-enhance-performance-and-control-costs)

MTTR stands for Mean Time To Repair. It measures the average time required to repair equipment and return it to normal operation after a failure. MTTR = The average time it takes to fix a failure and restore equipment to service. MTTR=Total DowntimeNumber of RepairsMTTR=Number of RepairsTotal Downtime​ Example: If a solar inverter fails 5 times in a year and the total downtime across those events is 50 hours: MTTR = 50 ÷ 5 = 10 hours This means, on average, it takes 10 hours to diagnose, repair, and return the inverter to service. https://static.wixstatic.com/media/1cf7b6_09398d391f7d4e089750bc5b0becde89~mv2.jpg • Lower MTTR = Faster repairs and less downtime • Higher MTTR = Longer outages and greater production loss • Helps evaluate maintenance team effectiveness and spare parts strategy • MTTR includes troubleshooting, repair, testing, and restart time. • It does not measure how often failures happen (that’s MTBF). • Reducing MTTR improves system availability and revenue performance. https://www.truckroll.tech/post/best-unused-metrics-in-renewables-mtbf-and-mttr-to-enhance-performance-and-control-costs(https://www.truckroll.tech/post/best-unused-metrics-in-renewables-mtbf-and-mttr-to-enhance-performance-and-control-costs)

Master Service Agreement is the contractual obligation of services, material, or goods.

Main Service Panel For grid-connected systems, the electrical panel of an address where the utility service conductors are connected. This panel will be the first thing after a utility meter and will typically have one to six service disconnects.

Minimum Viable Product is a product that meets the bare minimum requirements to launch and be successful. This can be a physical product, a software product, or even a set of documents (like user manuals and spec sheets). This is often used to define the minimum requirements needed to launch a new product or service with the intention of improving and adding more functionality and/or information later.

National Electrical Code is the regulations for electrical and fire safety published by the NFPA every three years and enforced by local jurisdictions. The intent of the NEC is to protect life and property by preventing electrical dangers and fires, it does not cover performance issues like whether a PV system is producing the expected energy. https://www.nfpa.org/education-and-research/electrical/understanding-nfpa-70-national-electrical-code(https://www.nfpa.org/education-and-research/electrical/understanding-nfpa-70-national-electrical-code)

NERC stands for the North American Electric Reliability Corporation. NERC is the organization responsible for developing and enforcing reliability standards for the bulk electric power system in North America. • Sets reliability and operational standards • Monitors grid performance • Investigates major grid disturbances • Oversees compliance and enforcement NERC standards apply to: • Transmission operators • Balancing authorities • Generator owners/operators (including large solar, wind, and BESS plants) • Reliability coordinators Utility-scale renewable projects connected to the bulk power system may be subject to: • NERC reliability standards • Registration requirements • Compliance audits This ensures renewable plants operate safely and support overall grid stability. https://www.nerc.com(https://www.nerc.com)

NEMA ratings are enclosure classifications developed by the National Electrical Manufacturers Association (NEMA)that define how well electrical equipment enclosures protect against environmental conditions. A NEMA rating tells you how protected an electrical enclosure is from water, dust, corrosion, and other hazards. NEMA ratings apply to electrical enclosures, not entire facilities. In clean energy, this includes: • Inverter cabinets • Combiner boxes • Disconnect switches • Switchgear enclosures • SCADA cabinets • Battery enclosures (external housings) Purpose: • Ensure equipment survives outdoor exposure • Prevent water intrusion and faults • Reduce corrosion and failure rates • Maintain safety compliance • Support long-term reliability Incorrect enclosure selection can lead to: • Ground faults • Arc flash risk • Premature equipment failure NEMA 1 • Indoor use only • Protects against basic contact • No protection against water Used for: Indoor panels in electrical rooms. NEMA 3R • Outdoor use • Protects against rain and ice • Not fully dust-tight Used for: • Outdoor disconnects • Meter cabinets • Some combiner boxes Very common in utility-scale solar. NEMA 4 • Indoor or outdoor • Protects against windblown dust and splashing water Used for: • Control panels • Certain inverter components NEMA 4X • Same as NEMA 4 • Plus corrosion resistance Used for: • Coastal solar projects • BESS enclosures • Harsh environments NEMA 12 • Indoor industrial use • Protects against dust, dirt, and dripping liquids Used for: • Control cabinets inside inverter stations

National Electrical Safety Code is the electrical regulations for the utility industry. https://standards.ieee.org/products-programs/nesc/(https://standards.ieee.org/products-programs/nesc/)

National Fire Protection Association is a global self-funded nonprofit organization, established in 1896, devoted to eliminating death, injury, property, and economic loss due to fire, electrical and related hazards. NFPA delivers information and knowledge through more than 300 consensus codes and standards, research, training, education, outreach, and advocacy. https://www.nfpa.org(https://www.nfpa.org)

National Renewable Energy Laboratory is a national laboratory of the US Department of Energy. now know as the National Laboratory of the Rockies. https://www.nlr.gov/index(https://www.nlr.gov/index)

Notice to Proceed is approval to proceed with project development usually to the next agreed upon check-in point."

The event in which the battery cell case vents gas due to a rise in the internal pressure of the cell. See NFPA 855.

Operations and Maintenance includes activities related to properly operating and maintaining each piece of equipment and the system as a whole such that it continues to produce energy safely, optimally, and meets all relevant codes and standards.

Occupational Safety and Health Administration is a government body belonging to the US Department of Labor created by Congress with the Occupational Safety and Health Act of 1970. OSHA ensures safe and healthful working conditions for working persons by setting and enforcing standards and by providing training, outreach, education, and assistance. https://www.osha.gov/(https://www.osha.gov/)

Power Conversion System (or sometimes referred to as a Power Conversaion Station) is a metal or concret skid that houses the inverter, pad mount transofmer, communications equipment, and tracker controls equipment). Also see inverter. https://static.wixstatic.com/media/1cf7b6_e46a3e0f4c854f4f8076a1393544ec8a~mv2.png

Permissible Exposure Limit is a legal limit for exposure of an employee to a chemical substance or physical agent such as high level noise.

Power Factor (PF) measures how efficiently electrical power is being used in an AC system. It shows the relationship between the power that actually performs useful work and the total power supplied. Power Factor = How effectively electrical power is converted into useful work. Power Factor=Real Power (kW)Apparent Power (kVA)Power Factor=Apparent Power (kVA)Real Power (kW)​ • Real Power (kW) = Power that does useful work • Apparent Power (kVA) = Total power supplied PF is expressed as a number between 0 and 1 (or as a percentage). If a facility draws: • 900 kW of real power • 1,000 kVA of apparent power PF=900÷1000=0.90PF=900÷1000=0.90 Power Factor = 0.90 (90%) That means 90% of the supplied power is doing useful work. Why it matters: • Higher PF (closer to 1.0) = More efficient system • Lower PF = More reactive power, higher losses • Utilities may charge penalties for low PF • Impacts equipment sizing (transformers, cables, breakers) Maintaining proper power factor: • Reduces losses • Improves grid stability • Ensures compliance with interconnection agreements

A PV system with rigid PV modules that are NOT building-integrated (i.e. not PV shingles nor PV tiles).

Programmable Logic Control is an industrial digital computer which has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, or robotic devices, or any activity that requires high reliability control and ease of programming and process fault diagnosis.

Pad Mount Trandformer (or MV Transformer) is the step up transformer from the output of the inverter to the distribution or transmission level voltages. https://static.wixstatic.com/media/1cf7b6_e46a3e0f4c854f4f8076a1393544ec8a~mv2.png

Point of Interconnect is the pont at which the system is connected to the larger electrical power grid. This is also a point of demarcation between where the scope of work for the utility is and the service provider for the system is.

Power Purchase Agreement is the formal agreement on the pricing structure and commitment of power to be generaated.

Personal Protective Equipment is designed to protect the wearer's body from injury or infection.

PR stands for Performance Ratio. It measures how efficiently a solar plant converts available sunlight into usable AC energy, after accounting for system losses. PR = How well the solar plant performs compared to its theoretical maximum output. PR=Actual Energy OutputTheoretical Energy Output Based on IrradiancePR=Theoretical Energy Output Based on IrradianceActual Energy Output​ It is expressed as a percentage. If a solar plant should theoretically produce 1,000 MWh based on measured sunlight, but actually produces 850 MWh: PR=850÷1000=0.85PR=850÷1000=0.85 PR = 85% This means the plant converted 85% of the available solar energy into electricity. PR reflects system losses such as: • Inverter losses • DC to AC conversion losses • Soiling (dust on panels) • Temperature losses • Wiring losses • Mismatch losses • Transformer losses It removes weather variability [so it measures system efficiency, not how sunny it was]. • Key KPI for solar asset performance • Used in EPC acceptance testing • Monitored by owners and lenders • Helps identify degradation or equipment issues • PR is primarily used for solar PV systems. • High availability does not guarantee high PR. • A typical healthy utility-scale solar plant PR may range from 80–90%, depending on design and location. Availability tells you if the plant is running. PR tells you how well it is running.

Potential Transformer or Voltage Transformer (VT) is an Instrument used for measuring voltage. It is specially designed to maintain an accurate voltage phase angle reference between the source and the Instrument Transformer`s output along with excellent voltage regulation to obtain accurate voltage measurements.

Production Tax Credit is an inflation-adjusted per-kilowatt-hour (kWh) tax credit for electricity generated by qualified energy resources and sold by the taxpayer to an unrelated person during the taxable year.

Photovoltaics is the process to generate power using devices that absorb energy from sunlight and convert it into electrical energy through semiconducting materials.

Quality Assurance/Quality Control - the combination of quality assurance, the process or set of processes used to measure and assure the quality of a product, and quality control, the process of ensuring products and services meet consumer expectations.

Qualified Electrical Worker is one who has received training in and has demonstrated skills and knowledge in the construction and operation of electric equipment and installations and the hazards involved.

Responsible Accountable Consulted Informed, this is a document that summarizes the roles and responsibilities of those involved in a project or program.

Root Cause Analysis is a collective term that describes a wide range of approaches, tools, and techniques used to uncover causes of problems.

Raw Material Index is equipment pricing that adjusts monthly based on the pricing of key raw material commodities (such as lithium, copper, electrolyte) that are used to manufacture that product. Raw material costs generally use a three month average.

Roundtrip Efficiency is the ratio of total output energy divided by total input energy over one charging/discharging cycle using rated input and output power. "Energy In" includes energy losses during charging due to the switchgear, AC lines, auxilary loads, transformer, inverter, and DC conductors. "Energy Out" includes energy losses during discharge due to the battery storage system, DC lines, inverter, transformer, auxilary loads, and switchgear. Site temperature, discharge duration, cycling profile, and auxilary load assumptions will impact RTE.

Regional Transmission Organizations are similar to ISOs and regulated by FERC, a joint group of utilities who operate the transmission systems for a particular region and develop innovative procedures to manage the transmission of electricity equitably. See definition of ISOs

Remote Terminal Unit is a microprocessor-controlled electronic device that interfaces mechanical and/or electrical equipment in the physical world to a SCADA system. RTUs send telemetry data to the supervisory computer(s) of a SCADA system and receive commands to control the equipment on site. Other terms that may be used for RTU are remote telemetry unit and remote telecontrol unit.

see RTU, RTAC is specific manufacturer.

Storage as a Transmission Asset is the use of an energy storage system as part of the electric transmission or distribution infrastructure to assist with the delivery, rather than supply, of electricity.By integrating storage into transmission equipment, SAT can inject or absorb electricity to facilitate power flows on transmission lines over a certain period of time. Used in this way, storage can enhance existing transmission lines or even serve as an alternative to building new transmission projects.

Substantial Completion is the stage when the construction of a project is deemed sufficiently completed and the site is capable of operating though may not yet have permission to operate from the utility and/or some final steps may still need to be completed. This milestone can vary project to project but is usually defined in the contract and may have legal implications if substantial completion is not done by the agreed upon date. It is a major milestone for any project which is why you may see a press release or announcement from an EPC when a project reaches substantial completion.

Supervisory Control and Data Acquisition is used for large-scale data collection and controls commonly used in a variety of industrial applications such as utility-scale power plants. Similar to monitoring but with the added ability to control the system and more often incorporates AI learning.

Safety Data Sheet (formerly known as MSDS) includes information such as the properties of each chemical, the physical, health, and environmental health hazards, protective measures,and safety precautions for handling, storing, and transporting the chemical.

SIF = Serious Injury or Fatality A Serious Injury or Fatality is any workplace incident that results in: • Death • Life-threatening injury • Permanent disability • Significant hospitalization (amputation, severe burns, paralysis, etc.) In clean energy construction and operations, SIF events typically involve: • Falls from height (trackers, turbines, substation steel) • Electrical contact (arc flash, medium voltage, backfeed) • Heavy equipment struck-by incidents • Trenching collapses • Rigging/lifting failures • Battery thermal runaway incidents in BESS facilities The key point: SIF events are low frequency, but extremely high severity. pSIF = Potential Serious Injury or Fatality A pSIF is an incident or near-miss that could have resulted in a serious injury or fatality—even if no one was hurt. Examples in clean energy: • A dropped tool from a tracker row that misses someone • A near miss with a telehandler backing up • A worker exposed to energized conductors but not shocked • A trench wall cracking before collapse • A battery rack overheating but contained before fire The injury didn’t happen—but the potential was there.

Subject Matter Expert is an individual with a deep understanding of a particular process, function, technology, machine, material or type of equipment.

State of Charge - percentage of usable energy currently in the battery, like a fuel gauge.

State of Health - Measure of battery aging and remaining capability, typically expressed as a percentage of original capacity or performance. 100% SOH = as good as new

Scope of Work is the work is to be carried out under a contract to complete a project, broken into deadlines and specific tasks.

Spill, Prevention, Control, and Countermeasures plan

The condition when an electrochemical cell increases its temperature through self-heating in an uncontrollable fashion and progresses when the cell's heat generation is at a higher rate than it can dissipate, potentially leading to off-gassing, fire, or explosion.

A SWPPP is a site-specific written plan required for construction projects — including solar farms, wind projects, battery storage, and other clean energy assets — that disturb one or more acres of land. Its purpose is to identify potential sources of stormwater pollution (mainly sediment, erosion, and construction-related pollutants) and outline Best Management Practices (BMPs) to prevent them from running off into nearby waterways, storm drains, or wetlands. Large-scale renewable projects involve significant ground disturbance for grading, roads, foundations, and trenching. Without a proper SWPPP: • Sediment and pollutants can harm local water quality. • Projects risk fines, stop-work orders, or permit violations from the EPA or state agencies (e.g., under NPDES or SPDES permits). Key elements typically included: • Erosion and sediment control measures (silt fences, straw wattles, stabilized entrances, etc.) • Pollution prevention practices (concrete washouts, fuel storage, spill response) • Inspection and maintenance schedules • Post-construction stormwater management (in many cases) The SWPPP must be prepared before construction starts, kept on-site, and followed throughout the project. It is usually required as part of the construction stormwater permit.

TRIR = Total Recordable Incident Rate It’s a standard safety metric used to measure the number of OSHA-recordable injuries and illnesses per 100 full-time workers over one year. TRIR helps compare safety performance across: • Projects • Companies • Contractors • Industries In clean energy construction (solar, wind, BESS), TRIR is commonly tracked by EPCs, developers, and asset owners. TRIR=Total OSHA Recordable Cases×200,000Total Hours WorkedTRIR=Total Hours WorkedTotal OSHA Recordable Cases×200,000​ Why 200,000? That represents 100 full-time workers working 40 hours/week for 50 weeks/year. TRIR Measures Frequency — Not Severity A cut needing stitches counts. A near-fatal electrical arc that didn’t injure anyone does not. This is why TRIR alone does not measure life-threatening risk. Per Occupational Safety and Health Administration (OSHA), a case is recordable if it involves: • Death • Days away from work • Restricted duty or job transfer • Medical treatment beyond first aid • Loss of consciousness • Significant diagnosed injury/illness Examples: • Laceration requiring stitches • Heat exhaustion requiring IV fluids • Back strain resulting in restricted duty • Electric shock requiring medical evaluation

Third-Party Service Provider - a contractor or company that does work for a system owner.

Upper Explosive Limit is the maximum concentration of a gas or vapor that will burn in air.

Uninterrupted Power Supply is an electrical apparatus that provides emergency power to a load when the input power source or mains power fails.

All enterprises engaged in the production and/or distribution of electricity for public use including those that are typically designated or recognized by governmental law or regulation by public service/utility commissions and that install, operate, and maintain electric supply such as generation, transmission, or distribution systems. https://static.wixstatic.com/media/nsplsh_5478207987c24ecc8ec4317bf59ed9ea~mv2.jpg

A VCB in substations stands for Vacuum Circuit Breaker. A VCB is a type of circuit breaker used primarily in medium-voltage systems (typically 1 kV to ~38 kV) to interrupt electrical current safely during: • Faults (short circuits, ground faults) • Switching operations (normal on/off control) Instead of using oil or gas, a VCB uses a vacuum as the arc-quenching medium: • When the breaker opens, contacts separate • An electrical arc forms briefly • The vacuum extinguishes the arc almost instantly because there are no gases to sustain it VCBs are popular in modern substations because they offer: • High reliability (long mechanical/electrical life) • Low maintenance (no oil handling or gas refilling) • Fast fault clearing (protects equipment quickly) • Compact design (fits well in switchgear lineup) On clean energy sites: • VCB → Vacuum → Medium voltage, low maintenance • SF₆ breaker → Gas → Higher voltage, more complex handling

The open circuit voltage (Voc) of a solar panel is the voltage of the panel when it is not connected to any load. It is measured without any current and is the maximum available voltage. https://static.wixstatic.com/media/1cf7b6_b7d1ccaf99654da786b8dcd2e7ad14f5~mv2.jpg