Knowledge Hub
A Glossary of Relevant Terms and Definitions
Knowledge Hub - Glossary of Relevant Terms and Definitions
This page contains a glossary of terms and definitions related to the concept of Sustainable Development. We have collected this information in order to provide a useful resource for those who wish to learn more about aspects of sustainability and sustainable development. For convenience of use, the glossary is divided into three sections:
- Society and Environment contains definitions of terms which provide context about the history and background of sustainability, as well as some current social and environmental concerns.
- Sector and Governance describes some of the sustainable development techniques used by the engineering industry, plus some of the regulations which govern them.
- Industry and Technology focuses on briefly describing a range of technologies and how they relate to sustainable engineering.
We believe that making information about these areas easily accessible, thereby enabling people to expand their knowledge, is a vital part of our vision of a sustainable future. Therefore, we have made this glossary freely available and is intended to be a live resource which will be regularly updated, revised and expanded as necessary.
Society & Environment
A proposed geological epoch to supersede the Holocene, popularised by atmospheric chemist Paul J. Crutzen in 2000 to describe the period in time within which human activity has significantly impacted Earth’s geology and ecosystems. The term is a combination of words adapted from ancient greek: anthropo (from anthropos, meaning human) and cene (from kainos, meaning new).
The term has not been officially recognised by the International Union of Geological Sciences (IUGS) but it is gaining popularity amongst academics and several models for the starting point have been proposed, including the advent of farming 8000 years ago, European colonisation of the Americas from the 1500s, the first ‘Industrial Revolution’ from 1760 and the end of the second world war.
Related Reading – ‘Geological Time Scale’, ‘Industrial Revolution’, IUGS
Biodiversity or Biological Diversity defines the variety and variability of genes, species and ecosystems on Earth. Biodiversity varies globally, meaning species are not equally distributed across the planet due to climatic variations. Evolution typically leads to an increase in biodiversity over time as species adapt to their conditions. Competition and environmental changes also leads to the natural extinction of some species, in what is known as the background extinction level. Dramatic changes to the environment can lead to sudden drops in biodiversity, with five known major extinction events having occurred throughout Earth’s history. The most famous of these is the Chicxulub asteroid impact which is believed to have caused the extinction of the dinosaurs 66 million years ago.
In 2019, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services published The Global Assessment Report on Biodiversity and Ecosystem Services. The report found that 25% of all plant and animal species are threatened by extinction due to human activity. (IPBES 2019) The high rate of extinction due to human activity is believed to be 1000 times greater than background levels. It is considered by some as Earth’s sixth mass extinction, and referred to as the Holocene extinction event.
Pure carbon (soot) in fine particles, which contribute greatly towards PM2.5 pollution in the air. These particles are generated by a range of activities including burning fossil fuels for transport, fuel and energy generation as well as the use of biomass for cooking and heating. Some particles are also naturally generated by forest fires, dust storms and volcanic activity.
These particles are 2.5 microns in size or smaller and are responsible for significant health problems, such as respiratory diseases, heart attacks and strokes and are classed by the World Health Organisation as a class 1 carcinogen. They also contribute to the greenhouse effect, and have a detrimental impact on weather patterns.
Social organisation is key in defining a civilisation, as it is required when a population of people develops to a point where individuals and groups gain specialisation in certain skills to contribute towards their society. This allows for population groups to grow beyond the size of small settlements.
The beginning of the bronze age around 3300BC is typically considered to be a key point in the development of the first civilisations in Mesopotamia and Egypt. Several other civilisations emerged independently across the world, centuries and millennia later in India, China and the Americas.
“A civilisation is a human society with its own social organisation and culture” (Collins Dictionary)
According to the UN, climate change refers to long-term shifts in temperatures and weather patterns. These shifts occur naturally and have a large number of causes, including the result of slight changes to the Earth’s tilt and orbit or volcanic activity. However, since the 1800s, human activities have been the main driver of climate change, primarily due to the burning of fossil fuels (like coal, oil and gas), which produce greenhouse gases.
The permanent removal of trees from an area of land which is then used for other purposes such as agriculture, mining or construction. Deforestation is ocurring across the world, with particularly large areas of tropical and subtropical forest being removed in South America and Africa.
The detrimental effects of deforestation are not just limited to a loss of biodiversity due to habitat destruction. Clearance of forested areas can lead to local issues such as an increased risk of flooding and soil erosion, as soil (and its water content) is held in place by tree roots. Removal of forest by logging and burning also releases large amounts of carbon dioxide stored within the trees, with 9 billion tonnes of carbon dioxide being emitted annually, or 17 percent of total global emissions (Berners-Lee, 2020).
Economic growth occurs when the GDP of a nation or region rises (Jackson T. 2017). This is usually expressed as a rate of growth percentage. See GDP for further information.
An ecosystem is a community of species, plus non-living elements such as rocks water and soil which exist in a defined area (Robertson M, 2017).
Embodied Carbon is the carbon dioxide emitted through the production process of a material. It measures greenhouse gas emissions from all stages of its life cycle. This includes the extraction of raw materials, transportation, processing and disposal of the product. Improving material efficiency is fundamental in the engineering sector to decrease the amount of embodied carbon emitted.
A lot of products claim to be carbon neutral however, often this does not include their embodied carbon emissions. It is frequently used in the construction industry to assess the carbon footprint of a building. To measure the embodied carbon from a building you would need to calculate the emissions from the mining of the materials used, their transportation and refinement of these materials, the construction of the building and the emissions from its demolition. It does not include the emissions released during the daily operation of the building. The amount of embodied carbon is normally not advertised to the consumer, but The Carbon Expert estimates that it accounts for nearly 50 % of a product’s emissions and 11 % of global emissions. To reach the government targets of Net Zero by 2050 the consideration and reduction of these emissions are vital to lowering the amount of carbon sequestration required. Methods to decrease the amount of embodied carbon include using more resilient materials that last longer and using a more efficient construction process. It also includes the use of low-carbon concrete mixes, less carbon-intensive materials, using recycled materials and renovation of buildings instead of new constructions.
Engineering has been used by humans for millennia, beginning with the development of primitive technologies such as the wheel and pulley thousands of years ago. Early engineering developments can be seen in structures such as the pyramids of Ancient Egypt and Stonehenge. These exact methods used to construct these vast ancient monuments are unknown, but engineering methods undoubtedly were used.
Great advances in engineering throughout the industrial, technological and digital revolutions from the 18th century onwards have transformed the way we live and, enabled us have a much more significant impact on the environment and climate.
“the study of using scientific principles to design and build machines, structures, and other things, including bridges, roads, vehicles, and buildings”
(Cambridge Dictionary)
A method of representing large periods of time through geological rock records. The following standard divisions are defined by the International Commission on Stratigraphy:
Eon – Several hundred million years.
Era – Tens to hundreds of million years.
Period – Millions to tens of millions of years.
Epoch – Hundreds of thousands to tens of millions of years.
Age – Thousands to millions of years.
Gases which contribute towards global warming when a part of the atmosphere. They trap solar radiation in the atmosphere which increases global temperatures in what is known as the greenhouse effect. There are a large number of different greenhouse gases, both naturally occurring and man-made, including Water Vapour (H2O), Carbon Dioxide (CO2), Methane (CH4), Ozone (O3), Nitrous Oxide (NO2), as well as various CFCs and HFCs.
The term was first coined in 1986 by environmentalist Jay Westervelt, who claimed that hotels which encourage customers to re-use towels for environmental reasons actually intend to benefit from the savings from reduced laundry costs. While initially intended to criticise framing cost-saving as environmentally friendly, the term has developed to describe exaggerated or misleading claims about the sustainability of a company’s products, services or operations.
Gross domestic product (GDP) is the financial value of all the goods and services produced and consumed by an economy. The GDP per capita divides the GDP by the population, giving the mean national income per person. (Jackson T. 2017).
The current geological epoch which began approximately 11 650 years ago, with the end of the last glacial period (ice age).
Industrial revolutions have occurred at various times across different parts of the world, but the following information is based on the industrialisation of the western world.
First Industrial Revolution: A period of technological innovation in Western Europe and North America from approximately 1760 to 1840. Prior to this point, society in these areas was predominantly agrarian with only small-scale industries producing materials such as textiles and metals. Increased use of waterpower and the invention of more sophisticated steam engines allowed for the development of mechanised systems and large factories. These developments led to widespread changes in society, with significant population increases and urbanisation.
Second Industrial Revolution: Also known as the Technological Revolution. This was a period between 1870 and 1914 (the start of the first world war). During this time, progress was made in the development of electricity, internal combustion engines and material sciences. Significant progress was made in power and transportation with the adoption of electrical systems and the internal combustion engine. Widespread expansion of telegram, telephone, water, sewerage and gas services also occurred during this time.
Third Industrial Revolution: Better known as the Digital Revolution. This is the ongoing shift from analogue to digital technology. The roots of the shift begin in 1947, with the invention of the transistor by John Bardeen and Walter Brattain while working in Bell Labs plus the further development of integrated circuit (IC) chips and MOSFET transistors in 1959. Technological developments which followed these initial inventions such as personal computers and the internet have led to a transformation how of business and manufacturing opearates. It has also dramatically changed wider society and lifestyles.
Fourth Industrial Revolution: Often referred to as Industry 4.0, a term popularised in 2015 by Klaus Schwab, the founder of the World Economic Forum (WEF). It describes the ongoing trend towards interconnectivity and smart automation, and its impact on industry and society. The ongoing developments in machine learning using the Internet of Things (IoT) and cloud-based computing allow systems to collect and analyse large amounts of data in order to improve efficiency and optimise operations. Further developments in this area are likely to be facilitated by the rollout of 5G systems.
“a rapid major change in an economy by
the general introduction of power-driven machinery or by an important
change in the prevailing types and methods of use of such machines”
Merriam Webster
A term which refers to the paradoxical situation where increased efficiency does not by itself lead to lower consumption; instead, efficiency makes energy less expensive so that people can afford to use more of it (Heinberg, 2011). The paradox was originally conceived by economist William Stanley Jevons in 1865.
The concept is an area of concern with regard to achieving a sustainable future, as technological developments which improve efficiency may not lead to a reduced consumption of energy and the planet’s resources. Instead, they may only lead to further economic growth with few benefits to the environment and society.
The derivation of the term and origins of the definition can be precisely traced to Hans Carl von Carlowitz ‘Sylvicultura Oeconomica’ (Economical Forestry), a treatise on forest management in Saxony, Germany, published in 1713. The term ‘Sustainability’ is a translation of the German ‘Nachhaltigkeit’, derived by Carlowitz from the existing German words ‘nachhaltend’ meaning persistent and ‘nutzung’ meaning use.
The Saxony region at the time was the global centre for ore mining and as a tax accountant and head mining administrator of the court of Kursachsen in Freiberg, Carlowitz produced his discourse to raise awareness of the commercial risk to the mining industry from declining local timber stock, owing to the unsustainable rate of deforestation. Timber was critical to mining operations, used in vast quantities for constructing mine shafts and smelting ores. Carlowitz’s observations however, went beyond simple economic security, describing in his text the natural environment as a ‘sacred realm’ to be protected alongside principles of ‘social ethics’ to sustain the way of life for future generations, and as such he is often cited as a forebearer of the modern-day Sustainable Development construct.
‘The property of being environmentally sustainable; the degree to which a process or enterprise is able to be maintained or continued while avoiding the long-term depletion of natural resources.’ (Oxford English Dictionary)
A relatively modern term and yet the principles can be traced back through every known civilisation over thousands of years to the very emergence of the Neolithic Revolution. First written in 1969, in a publication by the ‘International Union for Conservation of Nature’ (IUCN), the construct however, in its modern global context, is described within several revered texts as far back as 1662, in reference to an idealised philosophy for governing a developing society enacting an ever increasing demand on natural resources. A complex and multifarious concept with many interpretations, it stubbornly resists a comprehensive definition; however can be simply considered as an approach to prosper in a free, fair and resilient society with the underlying principles of environmental stability, economic security and social equality in balance.
One of the most influential early texts to explore Sustainable Development, is the Royal Society’s first ever publication, ‘Sylva’ – a discourse on forest management by John Evelyn. Commissioned in 1662 at the urgent request of the ‘Commissioners of his Majesties Navy’, concerned about forecasted shortages of timber from deforested woodlands impacting the construction of warships, Evelyn produced a highly detailed guide for the sustainable management of English forests. More importantly he challenged the notion of considering natural resources solely for the purpose of economic growth and advocated a more encompassing responsibility toward land management in general, considering not just the economic benefit but also the environmental and social responsibility to the next generation. Sylva was highly popular in its time, had an influence beyond its intended purpose that extended across Europe and endured well into the 18th century. The ideology became overshadowed with the emergence of the industrial revolution and a relentless focus on economic growth, however modern reflection of the text presents a profound realisation of the qualitative and complex interplay between the environment, economy and society, never more applicable than in today’s society.
The most widely applied definition is as characterised by the United Nations World Commission on Environment and Development (WCED) in their Brundtland Commission Report (Published as Our Common Future).
“Development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (Brundtland Commission, 1987)
‘A concept that is used to describe community and economic development in terms of meeting the needs of the present without compromising the ability of future generations to meet their needs.’ (Oxford English Dictionary)
Related Reading – ‘Sustainability’, ‘Natural Capital’, ‘Jevon’s Paradox’, ‘Industrial Revolution’, John Evelyn’s ‘Sylva’, Hans Carl von Carlowitz ‘Sylvicultura Oeconomica’
If something is true then it is factual, and not subjective or based on personal opinion.
In a court it is ‘the truth, the whole truth and nothing but the truth’. Very important when considering ‘greenwashing’ which often cites just elements of truth.
“something that is known to have happened or to exist, especially something for which proof exists, or about which there is information” (Cambridge dictionary).
Sector & Governance
A high-carbon form of charcoal, produced by heatiing organic matter to between 300C and 700C in an oxygen-free environment. The resulting material is stable and carbon-rich. According to the Climate Foundation, this material has numerous potential agricultural benefits, including managing soil pH, and increasing the water retention and fertility of soil (Climate Foundation, 2022). In addition to the agricultural benefits, biochar can be used as a method of carbon sequestration. The original material used to produce the biochar will have been removed from the atmosphere. The process of conversion produces a stable form of carbon which remains in the soil for decades without being re-emitted.
Blue carbon is carbon that is stored within ocean or coastal ecosystems, including algae, seagrass meadows, mangrove forests, coral reefs and salt marshes. These ecosystems are efficient carbon sinks and they each differ in their carbon sequestration capacity. It has been suggested that these ecosystems have 10 X the capability of capturing carbon compared to tropical forests. They capture carbon dioxide through photosynthesis and store it within their biomass over a short period of time. However, over longer geological time scales (up to thousands of years) they can store the carbon up to depths of 10m in their sediments or soil. Due to the lack of oxygen in these ecosystems, the decomposition of blue carbon into carbon dioxide is very slow, resulting in long-term carbon storage.
Blue carbon ecosystems can help limit the effects of climate change by reducing the number of greenhouse gases in the atmosphere. However, the current rate of loss of coastal ecosystems is a concern as they only cover a small area of the planet’s surface compared to terrestrial forests. According to the Office for Coast Management, approximately 7 % of global seagrasses are being lost every year as a result of pollution, human development and climate change. It is suggested that if these ecosystems were completely lost the equivalent of two to three years of global carbon emissions would be released (Reynard et al, 2020). Therefore, coastal habitat conservation is very important in our carbon mitigation schemes.
Disruptions can range from a change in legislation that forces change, to the loss of an employee. Continuity is the act of anticipating these disruptions and forming a plan to ensure that business operations can continue in the event of a disruption.
ISO 22300:2018 defines business continuity as: “the capability of an organization to continue the delivery of products or services at acceptable predefined levels following a disruption.”
Essentially, business resilience is the ability to recover from and adapt to potentially damaging incidents. Having the right mechanisms and contingencies in place empower companies to absorb business disruptions without severe impact to business operations.
According to ISO 22316:2017, business resilience is: “the ability of an organization to absorb and adapt in a changing environment to enable it to deliver its objectives and survive and prosper.”
A carbon credit is a verified, tradable, token which represents one tonne of carbon dioxide equivalent (tCO2e). Companies can buy credits by paying towards schemes which reduce greenhouse gas emissions, or remove carbon from the atmosphere. This can include investment in reforestation, renewable energy schemes, or direct carbon capture. There are two types of carbon credit:
Compliance Credits These are legally binding limits which are set by legislative bodies. The two most prominent compliance systems are the European Union Emissions Trading Scheme (EU-ETS) and the Californian cap-and-trade program. These schemes allocate credits to companies who can buy or sell them in accordance with their requirements. These schemes aim to issue fewer credits each year, thus reducing the overall emissions produced by the regions affected by the legislation. Other compliance schemes are in development across the world.
Voluntary Credits These allow individuals, companies, or organisations to offset their carbon emissions by purchasing carbon credits which have been verified by non-legislative bodies. There are numerous organisations which apply their own standards to verify credits, with Gold Standard and Verra among the two most prominent bodies.
According to the Greenhouse Gas Protocol, carbon emissions of a business can be divided into three scopes:
Scope 1: Processes which directly produce carbon emissions, such as fuel burned by company cars and gas for heating. Direct emissions can also be produced by industrial processes, refrigerants and leaks.
Scope 2: Emissions indirectly produced through the purchase and use of electricity, heat and steam.
Scope 3: All other indirect emissions from purchased goods and services, capital goods such as building and machinery, employees commuting, transport of goods and products, and waste disposal. It is important to consider all upstream and downstream activities which generate emissions within scope 3. For example, upstream transport emissions include those created transporting materials to a company’s facilities. Downstream transport emissions are those generated by transportation and distribution of a company’s products.
A measure of the full climate change impact of an individual, business, place, product or service. Measured in Carbon dioxide equivalent (CO2e), to account for the different impact of different greenhouse gases (see greenhouse gases).
Defined as any activity that compensates for the emission of carbon dioxide (CO2) or other greenhouse gases (measured in carbon dioxide equivalents, CO2e) by providing for an emission reduction elsewhere.
For example, a company or individual can calculate the carbon emissions they generate annually and offset this emission by investing in carbon-saving schemes such as renewable energy developments or reforestation.
The capture and storage of carbon dioxide. The term applies to a wide range of methods, both natural and artificial and is considered a key factor in both reducing emissions and the long-term removal of carbon dioxide from the atmosphere.
“the process of capturing and storing atmospheric carbon dioxide. It is one method of reducing the amount of carbon dioxide in the atmosphere with the goal of reducing global climate change.”
(USGS)
According to the European Commission, Eco-Innovation is “any innovation resulting in significant progress towards the goal of sustainable development, by reducing the impacts of our production modes on the environment, enhancing nature’s resilience to environmental pressures, or achieving a more efficient and responsible use of natural resources”
The Journal of Ecological Engineering defines Ecological Engineering as the “design of ecosystems for the mutual benefit of humans and nature”. It is a cross-discipline industry which utilises engineering principles to contribute towards ecological conservation and restoration.
The eight common forms of waste identified in Lean Manufacturing which can also commonly be applied to non-manufacturing situations. They include:
Defects – Waste generated by the reworking or replacement of a product that was not suitable for use. This wastes both time and resources.
Overproduction – Making products or items which are not required. The time and resources invested in making them is wasted and they then either have to be stored or disposed of.
Waiting – Time wasted waiting for processes to occur. This can be time lost by people waiting or through idle equipment.
Non-Utilised Talent – The under-utilisation of peoples’ talents, skills and knowledge.
Transportation – The unnecessary movement of goods which leads to wasted time and resources/energy.
Inventory – Generally linked to overproduction, an excessive inventory leads to wasted space. It also increases the requirements for tracking and management.
Motion – Similar to transportation, but generally applies to the unnecessary movement of people. For example, if a workspace is poorly laid out it can lead to employees wasting time having to move from place to place.
Extra Processing – Time and resources wasted making a product that is a higher quality than what is required, or using an unnecessarily complex method to produce it.
The development of new products, designs, or ideas. (Cambridge Dictionary)
A life cycle analysis (LCA) considers the environmental impacts of a product, service or process at all stages of its life span from cradle to grave. For a product, this includes the extraction of its raw materials (cradle) through to its manufacturing, distribution, use and disposal (grave). The standards and requirements of an LCA are laid out by the International Organisation for Standardisation (ISO 14040 and 14044).
Creating an LCA involves four stages. First, you need to define the goals and scope of the product you are accessing and the functional basis you will use for comparison. The next step involves an inventory analysis of the energy and materials required for its use. An impact assessment is then conducted which quantifies the impacts and these results can then be interpreted. This highlights any areas of production where there are opportunities for reducing emissions and limiting the negative effects on the environment. Aside from this, the other benefit of using LCA’s is that it does not allow for burden shifting, which is when the solution to one problem creates another issue in a different stage of the life cycle.
An example of an LCA for a Li-ion battery would include evaluating the environmental impacts of the following stages:
- Extraction of the rare-earth materials required to build the battery
- The transportation of these resources to the factory – this tends to have large environmental impacts as the resources are mainly found in remote locations globally
- The manufacturing process – which is very energy intensive
- The use of the battery – the environmental impacts from this, for a battery tend to be quite low
- Disposal – batteries have a life span and degradation over the years means that the materials must be disposed of. Currently, methods of recycling battery materials are limited
“a process of evaluating the effects that a product has on the environment over the entire period of its life thereby increasing resource-use efficiency and decreasing liabilities. It can be used to study the environmental impact of either a product or the function the product is designed to perform. LCA is commonly referred to as a “cradle-to-grave” analysis. LCA’s key elements are: (1) identify and quantify the environmental loads involved; e.g. the energy and raw materials consumed, the emissions and wastes generated; (2) evaluate the potential environmental impacts of these loads; and (3) assess the options available for reducing these environmental impacts”
European Environment agency
Also known as carbon neutrality, it is defined by the UN as “cutting greenhouse gas emissions to as close to zero as possible, with any remaining emissions re-absorbed from the atmosphere, by oceans and forests for instance”
Achieving carbon neutrality is recognised as the key requirement for minimising the impact of global warming on the planet, with the Paris agreement aiming to keep global temperatures below 1.5 degrees above pre-industrial levels. The 2015 agreement stated that emissions should be reduced by 45% by 2030, with a goal of reaching net zero by 2050.
Renewable energy is energy that is generated from renewable resources that are naturally replenished on a human timescale. It includes sources such as sunlight, wind, rain, tides, waves, and geothermal heat. Although most renewable energy sources are sustainable, some are not. For example, some biomass sources are considered unsustainable at
current rates of exploitation.
Six Sigma is a process improvement methodology that focuses on reducing defects and variability through data-driven analysis. Originally developed to enhance manufacturing quality, it uses structured techniques to achieve near-perfect performance. In the context of sustainability, Six Sigma helps organisations minimise waste, optimise resource use, and lower energy consumption. By improving efficiency and eliminating unnecessary steps, it supports environmental goals while reducing costs, making it a practical tool for businesses aiming to operate more responsibly.
Sustainable engineering applies the principles of engineering (as defined in this glossary) to contribute towards sustainable development.
Numerous techniques and practices are employed within sustainable engineering, including aiming to reduce carbon emissions by replacing fossil fuel dependent processes with alternative renewable energy technologies. Carbon emission reductions are also achievable through improving the efficiency of systems by reducing the consumption of energy and other resources – the transitions towards greater interconnectivity and smart systems, including the Internet of Things are key factors in this area. Sustainable engineering uses all these tecniques, collaborates with experts within the fields of ecology and business to help progress towards greater sustainability, all while maintaining a circular approach to design with life cycle analysis.
A term introduced by corporate responsibility expert John Elkington in 1997 to describe three dimensions of sustainable development – Environmental, Economic and Social. Alternatively known as People, Planet, Prosperity, and occasionally referred to as the three pillars of sustainability.
Industry & Technology
Better defined as additive manufacturing, is the process of creating a three-dimensional object by building up layers of material. Multiple different technologies are available for both polymer and metal-based processes. Additive manufacture has a wide range of applications, and is used for rapid prototyping and bespoke component manufacture, with limited usage within the automotive industry. It is also used within healthcare, particularly as a part of reconstructive surgery.
Bespoke 3-dimensional CAD models are required for additive manufacture. These models are “sliced” into layers for the printer to build up. Once an item has been printed, various finishing processes may be required to complete production. These include sanding, polishing, removal of temporary structural support and cleaning.
Intelligence which is displayed by machines. It is has a wide range of applications including production robots, voice recognition systems, self-driving cars. It is also used within search engines, social media algorithms and financial systems.
“The ability of a digital computer or computer-controlled robot to perform tasks commonly associated with intelligent beings.”
(Encyclopedia Britannica)
Bioenergy is a form or renewable energy produced by living organisms. It comes in different forms such as biomass and biofuels. According to IRENA in 2019 bioenergy accounted for 9 % of the primary global energy supply and it is estimated to account for 17 % (290 GW) by 2030. When coupled with carbon capture storage it is essential for our energy transition in the future to meet the 1.5˚C goal and achieve Net Zero. Plants produce biomass through photosynthesis as they harness the sun’s energy and store it as chemical energy. This energy can be released through combustion which can be used to directly heat buildings and water. Alternatively, the energy can be produced in a thermal plant where it is used to generate electricity by using a steam turbine.
Biomass sources include wood, agricultural crops, animal manure and biogenic waste from industry and households. It is one of the most primitive sources of energy and has been used for thousands of years for cooking and heating purposes. Biofuels are sources of bioenergy in the form of liquid or gas. An example of this includes animal manure as the methane (gas) produced from this waste can be collected and burnt to release heat. Methane is another type of greenhouse gas however; it has 25 times the amount of heat-trapping capability than carbon dioxide.
The largest biomass plant in the UK is DRAX Power Station. Historically this has been a coal plant, but in recent years it has converted its fuel source to biomass. It has an installed capacity of 645 MW and produced over 37, 000 GWh (gigawatt hours) of electricity in 2019.
A term which refers to all materials created from polymers which are derived from biomass sources, as opposed to fossil fuels. While bioplastics may have a lower environmental impact than conventional plastics, this is not guaranteed as the manufacturing process may be energy intensive. These materials are not always biodegradable due to their chemical make-up, therefore the term bio-based polymer has been suggested as a more appropriate name.
Applies to a range of different methods which capture carbon dioxide and store it to prevent it from being emitted into the atmosphere. There are four broad subcategories:
1. Conventional Carbon Capture and Storage (CCS) – Captures carbon dioxide at the location where it is being generated, such as from fossil-fuelled power stations, and stores it to prevent it being emitted into the atmosphere. The main aim of this is to maintain current CO2 levels while continuing to use existing technologies which generate it.
2. Bioenergy with Carbon Capture and Storage (BECCS) – As per conventional capture and storage, this method captures and stores carbon but from Bioenergy systems. This has an advantage over conventional capture as the biomass used to generate power will have removed carbon dioxide from the atmosphere.
3. Direct Air Carbon Capture and Storage (DACCS) – Removes carbon dioxide which is already present in the atmosphere and stores it. The main aim of this method is to reduce current atmospheric CO2 levels to nearer pre-industrial levels.
4. Enhanced Weathering – The process of natural erosion removes CO2 from the air as it reacts with silicate and carbonate rocks, forming stable carbon-containing minerals. These natural processes sequester around 1 billion tonnes of CO2 per year (Berners-Lee 2019). Enhanced weathering attempts to accelerate this process by finely grinding these rocks and spreading them on the land or sea. This removes CO2 from the atmosphere and has the added benefit of reducing ocean acidity.
The removal of salt and other minerals from water. It is already used in areas which experience water scarcity, with large plants in operation in the Middle East. It has been proposed as a potential solution to water shortages caused by increasing demand, climate change and ground water depletion. However, the process is costly, energy-intensive and produces large quantities of brine, which can potentially be contaminated with heavy metals.
Grid to Vehicle – Takes electricity from the supply grid and charges EV batteries. Currently, this is done via a cable and charging point.
Vehicle to Grid – Allows EV batteries to be used as a form of electricity storage which can be fed back into the grid during periods of high demand.
Vehicle to Vehicle – Allows transfer of charge between two electric vehicles.
Conventional, non-renewable sources of hydrocarbon energy which include coal, oil and natural gas. They were geologically formed over millions of years in the earth’s crust. Burning of fossil fuels currently accounts for the majority of global energy production and greenhouse gas emissions.
An electrochemical system which is used for the generation of electricity from Hydrogen. The cells split the electrons and protons from hydrogen, sending the electrons through a circuit to generate a current. After passing through the circuit the electrons combine with the protons and oxygen from the atmosphere. This process generates electricity and only generates heat and water as waste products.
Fuel cells have a number of applications, and can be used as an alternative to batteries in vehicles with electric motors. Fuel cell powered vehicles have not achieved the same popularity as battery-powered vehicles due to the challenges of producing, storing and distributing hydrogen.
Heat pumps are used to transfer thermal energy and are typically used to provide hot water for consumption or heating. They operate via the refrigeration cycle, compressing refrigerant gases which are at an outside temperature to extract thermal energy from the outside environment. Electricity is used to operate heat pumps, but they are typically more efficient that conventional electric water heating. Their efficiency is defined by their coefficient of performance (CoP), where a CoP of 2.5 means that for every watt of electricity used, 2.5 watts of heat are generated.
There are two main types of heat pump:
Air Source Heat Pumps (ASHPs). These extract heat from external air, and are currently the most popular type of heat as they are the easiest and cheapest to install. Their CoP can vary significantly depending on the outside temperature (they are less efficient at lower temperatures).
Ground Source Heat Pumps (GSHPs). These extract heat from the ground and require the digging of trenches or a borehole to lay the heat exchanging pipes containing the refrigerant. Consequently, they are more costly to install. Their CoP varies less than ASHPs due to the relative stability of ground temperatures.
Hydropower is the extraction of energy from moving water. Is has been used for hundreds of years in the form of water mills, utilising the kinetic energy from water wheels. Presently, its greatest application is the generation of electricity, making up 17% of the world’s generation in 2020 according to the International Energy Association. It is a source of low carbon renewable energy, as it is powered by Earth’s hydrological cycle. However, construction of large scale hydropower project use vast quantities of resources and can lead to major environmental and ecological changes due to the alteration of watercourses.
Related Reading – ‘Renewable Energy‘, ‘Embodied Carbon’
The Internet of Things (IoT) generally refers to equipping physical objects which aren’t traditional computing devices with sensors so they can communicate over the internet or other network. An example of this is the long-proposed concept of a “Smart Home” which utilises automated systems to control aspects such as heating, air quality and lighting. The Internet of Things is also considered a key part of Industry 4.0, as it relies heavily on the adoption of smart inter-connected manufacturing and distribution systems.
Aside from the many benefits of using interconnected systems, there are numerous concerns regarding security and privacy as these systems are at risk of cyberattacks or espionage. Insecure systems are especially vulnerable, allowing hackers to access sensitive data. There are also concerns that malware or ransomware could potentially be used to attack systems, leading to significant disruption. This could be particularly damaging, especially where IoT is used in critical circumstances such as healthcare or defence.
Known colloquially as splitting atoms. Nuclear fusion is the form of nuclear power used in current commercial power stations. In this process, a neutron is used to hit an atom (Usually Uranium-235) to split it into two smaller atoms. This process releases thermal energy and additional neutrons which can cause a chain reaction leading to the release of additional energy. The thermal energy from the nuclear reaction is used to generate steam and drive a turbine to generate electricity, as is typical in coal and gas fuelled power stations. Fusion energy has been used comercially since the 1950s and in 2020 provided 10% of the world’s electricity, according to the International Atomic Energy Agency (IAEA).
Fission energy is generally considered an important factor in the transition away from fossil fuels, as it is a highly efficient, well established technology which produces no direct CO2 emissions. The energy is not sustainable however, as there are only finite reserves of Uranium in the world and significant amounts of energy and resources are required to construct fission power stations. There also significant costs associated with the management of waste, plus the maintenance and decommissioning of facilities.
Unlike fission, nuclear fusion works by producing energy from combining atoms (typically hydrogen isotopes). The fusion of hydrogen into heavier atoms occurs in the sun, producing huge amounts of energy, making our planet habitable.
Achieving nuclear fusion artificially is technically challenging as immense temperatures and pressures need to be achieved to fuse atoms together. These conditions have been created in the uncontrolled fusion reactions of thermonuclear weapons, where a primary fission reaction is used to trigger a fusion reaction. Creating a controlled fusion reaction to safely generate energy is challenging and has not yet been comercially achieved, although progress towards maintaining a stable fusion reaction has been made in recent years.
Devices used to convert energy from sunlight into electricity. Typically, this applies to photovoltaic (PV) panels used to convert sunlight into usable electricity. According to the International Energy Agency, in 2020 PV generated 821TWh of energy, representing 3.1% of overall global energy production. Photovoltaic systems consist of arrays of panels which can be installed on roofs, walls and on the ground. They produce no greenhouse gases when operating, although they are energy and material intensive to manufacture. Solar cells are using semiconducting materials, predominantly silicon which is a very abundant metal. Photovoltaic systems consist of arrays of panels which can be installed on roofs, walls and on the ground. They produce no greenhouse gases when operating, although they are energy and material intensive to manufacture.
The popularity of PV energy has been rapidly increasing since the 1990s as a result of a reduction in its price however, it is not without its constraints. The main issue with PV cells is the intermittency of their electricity supply. PV systems can only generate energy during daylight hours and their output may be reduced during cloudy and wet weather to between 10% and 25% of their output rating (https://www.solarempower.com/). This means they require large energy storage systems such as a battery. On a small scale, this is achievable however our batteries currently do not have the capacity for us to solely rely on PV. The other issue is the amount of land use that solar farms require to generate a decent supply of electricity. Retrofitting houses with PV arrays provides a solution to this and provides an independent supply of electricity, thereby reducing reliance on the grid.
Windpower has been harnessed for thousands of years in the form of ship sails, and since the medieval period in the form of windmills. The use of wind power to generate elctricity has been around sincle the late 1800s, and small scale wind turbines were common across rural parts of the US and other countries for pumping water and providing power for farms.
Recent decades have seen a significant developments in wind turbine technology. In the UK, wind turbine generation capacity quadrupled between 2010 and 2020 to 24GW. In 2019, 64.1TWh of energy were generated. According to the government, this represents 19.9% of the total energy generated that year.