Efficient energy use in the context of Energy development

A sustainable city, eco-city, or green city is a city designed with consideration for the social, economic, and environmental impact (commonly referred to as the triple bottom line), as well as a resilient habitat for existing populations. The UN Sustainable Development Goal 11 defines as one that is dedicated to achieving green, social, and economic sustainability, facilitating opportunities that prioritize inclusivity as well as maintaining a sustainable economic growth. Furthermore, the objective is to minimize the inputs of energy, water, and food, and to drastically reduce waste, as well as the outputs of heat, air pollution (including CO2, methane, and water pollution).

The UN Environment Programme calls out that most cities today are struggling with environmental degradation, traffic congestion, inadequate urban infrastructure, in addition to a lack of basic services, such as water supply, sanitation, and waste management. A sustainable city should promote economic growth and meet the basic needs of its inhabitants, while creating sustainable living conditions for all. Ideally, a sustainable city is one that creates an enduring way of life across the four domains of ecology, economics, politics, and culture. The European Investment Bank is assisting cities in the development of long-term strategies in fields including renewable transportation, energy efficiency, sustainable housing, education, and health care. The European Investment Bank has spent more than €150 billion in bettering cities over the last eight years.

Energy development is the field of activities focused on obtaining sources of energy from natural resources. These activities include the production of renewable, nuclear, and fossil fuel derived sources of energy, and for the recovery and reuse of energy that would otherwise be wasted. Energy conservation and efficiency measures reduce the demand for energy development, and can have benefits to society with improvements to environmental issues.

Societies use energy for transportation, manufacturing, illumination, heating and air conditioning, and communication, for industrial, commercial, agricultural and domestic purposes. Energy resources may be classified as primary resources, where the resource can be used in substantially its original form, or as secondary resources, where the energy source must be converted into a more conveniently usable form. Non-renewable resources are significantly depleted by human use, whereas renewable resources are produced by ongoing processes that can sustain indefinite human exploitation.

Energy security is the association between national security and the availability of natural resources for energy consumption (as opposed to household energy insecurity). Access to cheaper energy has become essential to the functioning of modern economies. However, the uneven distribution of energy supplies among countries has led to significant vulnerabilities. International energy relations have contributed to the globalization of the world leading to energy security and energy vulnerability at the same time.

Renewable resources and significant opportunities for energy efficiency and transitions exist over wide geographical areas, in contrast to other energy sources, which are concentrated in a limited number of countries. Rapid deployment of wind power and solar power and energy efficiency, and technological diversification of energy sources, would result in significant energy security.

A façade or facade (/fəˈsɑːd/ ; ) is the front part or exterior of a building. It is a loanword from the French façade (pronounced [fasad]), which means "frontage" or "face".

In architecture, the façade of a building is often the most important aspect from a design standpoint, as it sets the tone for the rest of the building. From the engineering perspective, the façade is also of great importance due to its impact on energy efficiency. For historical façades, many local zoning regulations or other laws greatly restrict or even forbid their alteration.

A motion detector is an electrical device that utilizes a sensor to detect nearby motion (motion detection). Such a device is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area. They form a vital component of security, automated lighting control, home control, energy efficiency, and other useful systems. It can be achieved by either mechanical or electronic methods. When it is done by natural organisms, it is called motion perception.

Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively (using less and better sources of energy for continuous service) or changing one's behavior to use less and better source of service (for example, by driving vehicles which consume renewable energy or energy with more efficiency). Energy conservation can be achieved through efficient energy use, which has some advantages, including a reduction in greenhouse gas emissions and a smaller carbon footprint, as well as cost, water, and energy savings.

Green engineering practices improve the life cycle of the components of machines which convert energy from one form into another.

The energy efficiency in transport is the useful travelled distance, of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels, electrical energy or food energy. The energy efficiency is also occasionally known as energy intensity. The inverse of the energy efficiency in transport is the energy consumption in transport.

Energy efficiency in transport is often described in terms of fuel consumption, fuel consumption being the reciprocal of fuel economy. Nonetheless, fuel consumption is linked with a means of propulsion which uses liquid fuels, whilst energy efficiency is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the International System of Units, i.e., joules.

EU Directive 92/75/EC (1992) established an energy consumption labelling scheme. The directive was implemented by several other directives thus most white goods, light bulb packaging and cars must have an EU Energy Label clearly displayed when offered for sale or rent. The energy efficiency of the appliance is rated in terms of a set of energy efficiency classes from A to G on the label, A being the most energy efficient, G the least efficient. The labels also give other useful information to the customer as they choose between various models. The information should also be given in catalogues and included by internet retailers on their websites.

In an attempt to keep up with advances in energy efficiency, A+, A++, and A+++ grades were later introduced for various products; since 2010, a new type of label exists that makes use of pictograms rather than words, to allow manufacturers to use a single label for products sold in different countries.

NABERS, the National Australian Built Environment Rating System is an Australian national initiative, managed by the Government of New South Wales' Department of Climate Change, Energy, the Environment and Water (New South Wales) on behalf of the Australian Government, that measures and compares the environmental performance of Australian buildings and tenancies.

There are NABERS rating tools for commercial office buildings to measure greenhouse gas emissions, energy efficiency, water efficiency, waste efficiency and indoor environment quality. There are also energy/greenhouse and water rating tools for hotels, shopping centres and data centres.

Heat recovery ventilation (HRV), also known as mechanical ventilation heat recovery (MVHR) is a ventilation system that recovers energy by operating between two air sources at different temperatures. It is used to reduce the heating and cooling demands of buildings.

By recovering the residual heat in the exhaust gas, the fresh air introduced into the air conditioning system is preheated (or pre-cooled) before it enters the room, or the air cooler of the air conditioning unit performs heat and moisture treatment. A typical heat recovery system in buildings comprises a core unit, channels for fresh and exhaust air, and blower fans. Building exhaust air is used as either a heat source or heat sink, depending on the climate conditions, time of year, and requirements of the building. Heat recovery systems typically recover about 60–95% of the heat in the exhaust air and have significantly improved the energy efficiency of buildings.

Passive house (Passivhaus) is a voluntary building performance standard for very high energy efficiency and thermal comfort that substantially reduces a building’s carbon footprint. Buildings certified to the standard are ultra-low energy and typically require very little energy for space heating or cooling. The approach is used for housing and for non-residential buildings such as offices, schools, kindergartens and healthcare facilities. Energy efficiency is integral to architectural design rather than an add-on. Although most common in new construction, the principles are also applied in deep renovations (see EnerPHit).

As of January 2025, projects certified by the Passive House Institute (PHI) comprise over 47,400 units with about 4.32 million m² of treated floor area (TFA) worldwide; the public PHI database lists nearly 6,000 projects. In North America, the Passive House Institute US (PHIUS) reported 500+ total certified projects and ~1.6 million ft² certified in 2024 alone, with 4.4 million ft² design-certified that year. While early adoption concentrated in German-speaking countries and Scandinavia, certified projects are now documented across diverse climate zones, including hot-humid and tropical regions.

Energy management includes planning and operation of energy production and energy consumption units as well as energy distribution and storage. Energy management is performed via energy management systems (EMS), which are designed with hardware and software components to implement the tasks. Energy management can be classified into building energy management, grid-scale energy management (including grid energy storage), and marine energy management.

Energy management objectives are resource conservation, climate protection and cost savings, while the users have permanent access to the energy they need. It is connected closely to environmental management, production management, logistics and other established business functions. The VDI-Guideline 4602 released a definition which includes the economic dimension: "Energy management is the proactive, organized and systematic coordination of procurement, conversion, distribution and use of energy to meet the requirements, taking into account environmental and economic objectives". It is a systematic endeavor to optimize energy efficiency for specific political, economic, and environmental objectives through engineering and management techniques.

A lighting control system is intelligent network-based lighting control that incorporates communication between various system inputs and outputs related to lighting control with the use of one or more central computing devices. Lighting control systems are widely used on both indoor and outdoor lighting of commercial, industrial, and residential spaces. Lighting control systems are sometimes referred to under the term smart lighting. Lighting control systems serve to provide the right amount of light where and when it is needed.

Lighting control systems are employed to maximize the energy savings from the lighting system, satisfy building codes, or comply with green building and energy conservation programs. Lighting control systems may include a lighting technology designed for energy efficiency, convenience and security. This may include high efficiency fixtures and automated controls that make adjustments based on conditions such as occupancy or daylight availability. Lighting is the deliberate application of light to achieve some aesthetic or practical effect (e.g. illumination of a security breach). It includes task lighting, accent lighting, and general lighting.