Glossary
PacWave
**PacWave** is an open-ocean wave energy testing facility developed by Oregon State University (OSU) in partnership with the U.S. Department of Energy and the State of Oregon. Located approximately seven miles off the coast of Newport, Oregon, PacWave provides a grid-connected environment for testing utility-scale wave energy converters (WECs). The facility comprises two sites, including PacWave South, which features four offshore test berths connected to an onshore Utility Connection and...
Paleoclimate Reconstruction
**Paleoclimate Reconstruction** is the scientific endeavor aimed at understanding Earth's past climates by analyzing geological and biological records. By utilizing data from natural archives such as ice cores, tree rings, sediment layers, and corals, researchers can infer temperature changes, atmospheric compositions, and ecological shifts over millennia. These reconstructions provide crucial insights into climate variations before modern weather records began, offering a baseline to compare...
Palm Oil
**Palm oil** is an edible vegetable oil extracted from the fruit of the oil palm tree (Elaeis guineensis), primarily cultivated in tropical regions such as Indonesia and Malaysia. It is one of the most widely used and efficient vegetable oils, valued for its high yield per hectare and versatility. Palm oil is commonly found in processed foods, cosmetics, detergents, and biofuels. It exists in two main forms: crude palm oil, derived from the fruit’s flesh, and palm kernel oil, extracted from...
Paper Waste
**Paper waste** refers to discarded paper and paper-based products generated by households, businesses, institutions, and industrial activities. Common examples include office paper, newspapers, magazines, cardboard, packaging materials, paper bags, and paperboard products. It is one of the largest and most widely recycled waste streams in many countries.
Paper waste plays an important role in circular economy strategies because paper fibers can often be recovered and reused multiple times...
Parabolic Trough
A **Parabolic Trough** is a type of solar energy collector that uses a parabolic-shaped reflector to concentrate sunlight onto a receiver tube. This receiver tube, typically positioned along the focal line of the mirror, contains a heat-absorbing fluid that captures the concentrated solar energy. As the fluid heats up, it can be used to produce steam, which in turn drives a turbine to generate electricity. This technology is a key component in many solar thermal power plants, contributing...
Paris Agreement
The **Paris Agreement** is a landmark international accord adopted by nearly every nation in 2015 to address climate change and its negative impacts. The Agreement's central aim is to strengthen the global response to the threat of climate change by keeping a global temperature rise well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius. Additionally, the Paris Agreement seeks to enhance the ability...
Pebble Bed Reactor (PBR)
A **Pebble Bed Reactor (PBR)** is an innovative type of nuclear reactor that uses small, spherical fuel elements, often referred to as "pebbles," to generate heat and, subsequently, electricity. These pebbles are typically composed of a uranium dioxide or uranium carbide core encased in a graphite shell, which acts as a moderator to slow down neutrons, enhancing the efficiency of the fission process. This design inherently simplifies reactor construction and operational control, promoting...
Perfluorocarbons (PFCs)
**Perfluorocarbons (PFCs)** are a group of human-made compounds composed of carbon and fluorine atoms. These powerful greenhouse gases are colorless, odorless, and have a high degree of chemical stability, which allows them to persist in the atmosphere for thousands of years once released. PFCs are primarily produced as by-products during industrial processes like aluminum production, electronics manufacturing, and certain types of chemical synthesis.
Despite their relatively low...
Permafrost
**Permafrost** refers to a layer of soil or rock that remains frozen for at least two consecutive years. Found primarily in polar regions such as the Arctic and Antarctic, as well as in alpine regions, permafrost accounts for roughly 24% of the exposed land surface in the Northern Hemisphere. Its organic-rich soil holds significant amounts of carbon, making it a critical element in the Earth's carbon cycle and climate system.
Permafrost can be found beneath a surface layer known as the...
Perovskite Solar Cells
**Perovskite Solar Cells** are an innovative type of photovoltaic technology that utilizes a unique class of materials known as perovskites for light absorption and energy conversion. Named after the mineral structure they resemble, perovskites offer a crystalline composition that is highly efficient at converting sunlight into electricity. This cutting-edge technology is gaining significant attention due to its potential to achieve high power conversion efficiencies at a lower production...
Petrochemical Systems
**Petrochemical systems** are the integrated networks of processes, facilities, equipment, and control mechanisms used to convert crude oil, natural gas, and other hydrocarbon feedstocks into petrochemicals and related products. These systems encompass upstream feedstock handling, midstream processing units (such as cracking, reforming, and separation), and downstream manufacturing operations that produce basic chemicals, polymers, synthetic fibers, resins, solvents, and fuels. Petrochemical...
PFAS (Per- and Polyfluoroalkyl Substances)
**PFAS (per- and polyfluoroalkyl substances)** are a large group of synthetic chemicals characterized by strong carbon–fluorine bonds that make them resistant to heat, water, and oil, widely used since the 1940s in products such as non-stick cookware, firefighting foams, textiles, and food packaging; they are often called “forever chemicals” because they do not break down easily, can accumulate in people and the environment, and have been linked to health risks including cancer, liver and...
Photovoltaic Cells
**Photovoltaic Cells** are specialized semiconductor devices designed to convert sunlight directly into electricity through the photovoltaic effect. These cells are the fundamental building blocks of solar panels and are pivotal in the generation of renewable energy. By harnessing sunlight, photovoltaic cells can produce clean, sustainable electricity without emitting greenhouse gases, thereby making a significant contribution to combatting climate change and reducing our dependence on fossil...
Photovoltaic Effect
**Photovoltaic Effect** is the phenomenon through which solar energy is converted directly into electrical energy. This effect occurs when photons, or light particles, strike a semiconductor material, typically silicon, causing the release of electrons. These free electrons then create an electric current as they flow through the material. This foundational principle is the bedrock of solar panel technology and is crucial for the transition to renewable energy sources.
The **Photovoltaic...
Photovoltaic Efficiency
**Photovoltaic Efficiency** refers to the ability of a solar cell to convert sunlight into usable electrical energy. This efficiency is a crucial metric in determining the overall performance and effectiveness of a solar panel system. The higher the efficiency, the more electrical output you can generate from the same amount of sunlight, making it an essential consideration for both residential and commercial solar installations.
Several factors influence **Photovoltaic Efficiency**,...
Photovoltaic panels (PV panels)
**Photovoltaic panels (PV panels)** are devices that convert sunlight directly into electricity through the photovoltaic effect. When sunlight hits semiconductor materials such as silicon, it excites electrons and creates an electric current. Each panel is made up of many solar cells protected by glass, encapsulation layers, a backsheet, and a frame. The electricity produced is direct current (DC), which can be used directly, stored in batteries, or converted into alternating current (AC)...
Photovoltaic Thermal Hybrid Solar Collector (PVT)
A **Photovoltaic Thermal Hybrid Solar Collector (PVT)** is an advanced renewable energy technology that integrates both photovoltaic (PV) and thermal (T) systems within a single unit. This innovative device is designed to optimize the use of solar energy by simultaneously generating electricity and capturing usable heat. The PV component consists of solar cells that convert sunlight into electrical energy, while the thermal aspect involves a heat exchanger that absorbs the excess heat from...
Phytoremediation
**Phytoremediation** is the use of plants, and the microbes associated with their roots, to reduce, remove, stabilise or break down pollutants in soil, water or sediment. Certain plants can absorb contaminants through their roots and store them in stems, leaves or flowers, while others help immobilise pollutants in the soil or stimulate microbial activity that degrades harmful substances. It can be used for metals, hydrocarbons, solvents, pesticides and some persistent chemicals, depending on...
Pitch System
A **Pitch System** is a structured framework designed to streamline the process of preparing and delivering pitches or presentations, whether for business proposals, project ideas, or investment opportunities. This system encompasses various elements, including research, content creation, design, practice, and delivery techniques, to ensure that each pitch is compelling, informative, and persuasive.
The core components of an effective Pitch System involve understanding the target audience,...
Planetary Albedo
**Planetary Albedo** refers to the measure of reflectivity of a planet's surface, which determines how much sunlight is reflected back into space without being absorbed. On Earth, various surfaces like ice caps, oceans, forests, and deserts contribute to this reflectivity. A planet’s albedo is influenced by its atmosphere, including cloud cover and atmospheric particles. Essentially, higher albedo values indicate surfaces that reflect a larger portion of incoming solar radiation.
The Earth’s...
Plasma Confinement
**Plasma Confinement** refers to the methods and technologies employed to maintain and control plasma, a state of matter composed of charged particles, within a specified region for an extended period. The stability and retention of plasma are critical for applications like nuclear fusion, where sustaining high temperature and pressure conditions is essential for energy production. Achieving effective plasma confinement helps in averting the dispersal of energy and particles, thus enabling a...
Plastic Credits
**Plastic credits** are transferable certificates that represent a verified quantity of plastic waste that has been collected, recycled, recovered, or prevented from entering the environment. They are used by companies and organisations to finance plastic waste management projects, often in regions with weak collection, sorting, or recycling infrastructure. One credit commonly equals one kilogram or one tonne of plastic waste, depending on the scheme. Credible plastic credits should be...
Polar Amplification
**Polar Amplification** refers to the phenomenon where climate change effects are intensified in polar regions compared to the rest of the world. This acceleration in warming is primarily observed in the Arctic and, to a lesser extent, in the Antarctic regions. The warming rate in these areas is significantly higher than the global average, leading to pronounced environmental changes such as ice melt, shifting weather patterns, and impacts on local ecosystems.
The primary driver behind polar...
Polycrystalline Silicon Panels
**Polycrystalline Silicon Panels** are a type of photovoltaic (PV) solar panel made from silicon crystals. These panels are composed of multiple silicon fragments melted together to form the wafers used in the panel. Known for their blue hue and speckled appearance, polycrystalline panels are a popular choice in the renewable energy market due to their cost-effectiveness and adequate efficiency levels.
The manufacturing process of polycrystalline silicon involves melting raw silicon, which...
Polyethylene terephthalate (PET)
**Polyethylene terephthalate (PET)** is a thermoplastic polymer resin belonging to the polyester family, widely used for its strength, transparency, chemical resistance, and recyclability. It is formed through the polycondensation reaction of ethylene glycol and terephthalic acid, producing long molecular chains that can be melted and reshaped multiple times without major degradation.
PET is lightweight, durable, and resistant to moisture and most solvents, which makes it ideal for...
Polypropylene (PP)
**Polypropylene (PP)** is a thermoplastic polymer made from the monomer propylene (or propene). It belongs to the polyolefin family and is produced through chain-growth polymerization of propylene using catalysts such as Ziegler–Natta or metallocenes. Polypropylene is known for its low density, high chemical resistance, toughness, and versatility. It can be easily molded, extruded, or spun into fibers and films. PP is widely used in packaging, textiles, automotive components, medical devices,...
Polyurethane
**Polyurethane** is a versatile polymer composed of organic units joined by urethane (carbamate) links. It is created through a chemical reaction between a polyol (a molecule with multiple hydroxyl groups) and a diisocyanate or polyisocyanate.
Depending on its formulation, polyurethane can be flexible, rigid, soft, or hard, making it one of the most adaptable plastics in modern manufacturing.
Portable Emissions Measurement Systems (PEMS)
**Portable Emissions Measurement Systems (PEMS)** are mobile emissions-testing devices used to measure pollutants from vehicles and engines during real-world operation rather than under laboratory conditions. Installed directly on vehicles, PEMS combine gas analyzers, exhaust flow meters, GPS, and environmental sensors to monitor GHG emissions such as nitrogen oxides (NOx), carbon dioxide (CO₂), carbon monoxide (CO), and particulate matter in real time. PEMS are widely used in Real Driving...
Power Purchase Agreements (PPAs)
A Power Purchase Agreement is a long-term contract under which an organisation agrees to buy electricity from a specific power generator at a pre-agreed price, typically for 5–20 years. PPAs are widely used to finance renewable energy projects, provide price certainty for buyers, and help companies secure renewable electricity and associated environmental certificates without owning generation assets directly.
Pradhan Mantri Surya Ghar Muft Bijli Yojana
**Pradhan Mantri Surya Ghar Muft Bijli Yojana** is a national rooftop solar programme launched by the Government of India in 2024 to accelerate household-level solar adoption and reduce electricity costs. The scheme aims to equip one crore households with grid-connected rooftop solar systems, providing up to 300 units of free electricity per month to eligible beneficiaries. It offers central financial assistance through direct subsidies, simplified installation processes, and access to...
Precautionary Principle
The **precautionary principle** is a decision-making idea used when an action might harm people or the environment but science is not yet certain how or how much. Instead of waiting for full proof, the principle says it is better to prevent possible damage by acting early or choosing safer options. It is often summarized as “better safe than sorry.” This helps governments and organizations avoid serious or irreversible harm by being cautious even under uncertainty, especially in environmental...
Predictive Emissions Monitoring System
A **Predictive Emissions Monitoring System (PEMS)** is a software-based system that estimates industrial air pollutant emissions using mathematical models, process data, and operational parameters rather than continuous physical stack measurements alone. Commonly used in power generation, manufacturing, and industrial facilities, PEMS helps operators monitor pollutants such as nitrogen oxides (NOx), sulfur dioxide (SO₂), carbon monoxide (CO), and carbon dioxide (CO₂) in real time for...
Pressurized Water Reactor (PWR)
A **Pressurized Water Reactor (PWR)** is a type of nuclear reactor that uses water as both a coolant and a neutron moderator. In a PWR, the reactor core generates heat, and this heat is transferred to the water under high pressure, preventing it from boiling. The pressurized water, which reaches temperatures around 300°C, is then circulated through a series of tubes in the steam generator.
Inside the steam generator, the heat from the pressurized water is transferred to a secondary water...
Principal Adverse Impacts (PAI)
**Principal Adverse Impacts** (PAI) are a set of mandatory sustainability indicators under the EU Sustainable Finance Disclosure Regulation (SFDR) that measure the most significant negative effects of investment decisions on environmental, social, and governance (ESG) factors. Financial market participants use PAIs to assess and disclose impacts such as greenhouse gas emissions, biodiversity loss, human rights issues, and board diversity, improving transparency for investors and other...
Producer Responsibility Organization
A **Producer Responsibility Organization (PRO)** is a third-party entity that manages the collection, recycling, and responsible disposal of products on behalf of producers to ensure compliance with Extended Producer Responsibility (EPR) regulations. PROs help streamline regulatory obligations and support circular economy goals by coordinating logistics, reporting, and sustainable end-of-life solutions across product categories.
Product Carbon Footprint (PCF)
A **Product Carbon Footprint** (PCF) measures the total greenhouse gas emissions, expressed in CO₂ equivalents, generated throughout a product's life. This "cradle-to-grave" view includes extracting raw materials, manufacturing, transportation, use, and final disposal or recycling. Think of it as a climate impact score for an item, like a loaf of bread or a t-shirt. A lower PCF means the product contributes less to climate change, helping consumers make informed choices and companies reduce...
Product Category Rules (PCRs)
**Product Category Rules (PCRs)** are standardised, product-specific guidelines that define how the environmental impacts of a product must be assessed and reported in an Environmental Product Declaration (EPD). They specify key methodological choices—such as system boundaries, functional units, data quality requirements, and impact categories—ensuring that lifecycle assessments (LCAs) are carried out consistently for products within the same category. By requiring all manufacturers to follow...
Pyrolysis
**Pyrolysis** is a thermochemical process that decomposes organic material at elevated temperatures in the absence of oxygen. This innovative technology breaks down complex molecules into simpler compounds, resulting in the production of solid char, liquid bio-oil, and combustible gases. The absence of oxygen during pyrolysis is crucial, as it prevents combustion and allows for the recovery of valuable by-products that can be utilized in various industrial applications, from renewable energy...