Energy budget

In the built environment, the term 'energy' is typically used in the context of generating heat, powering equipment, creating products and materials, transportation, and so on.

An energy budget is a specific target for Energy Use Intensity (EUI) that must not by exceeded, where Energy Use Intensity is an annual measure of the total energy consumed in a building. Ref Climate Emergency Design Guide: How new buildings can meet UK climate change targets, published by the London Energy Transformation Initiative (LETI) in January 2020.

Climate Change 2021 – The Physical Science Basis, Annex VII: Glossary, written by the Intergovernmental Panel on Climate Change (IPCC) and published by Cambridge University Press in 2023, states: ‘The Earth is a physical system with an energy budget that includes all gains of incoming energy and all losses of outgoing energy. The Earth’s energy budget is determined by measuring how much energy comes into the Earth system from the Sun, how much energy is lost to space, and accounting for the remainder on Earth and its atmosphere. Solar radiation is the dominant source of energy into the Earth system. Incoming solar energy may be scattered and reflected by clouds and aerosols or absorbed in the atmosphere. The transmitted radiation is then either absorbed or reflected at the Earth’s surface. The average albedo of the Earth is about 0.3, which means that 30% of the incident solar energy is reflected into space, while 70% is absorbed by the Earth. Radiant solar or shortwave energy is transformed into sensible heat, latent energy (involving different water states), potential energy, and kinetic energy before being emitted as infrared radiation. With the average surface temperature of the Earth of about 15°C (288 K), the main outgoing energy flux is in the infrared part of the spectrum.’

See also: Energy intensity and Carbon budget.

[edit] Related articles on Designing Buildings

• Carbon budget.
• Climate Emergency Design Guide.
• Electricity.
• Energy.
• London Energy Transformation Initiative.
• National grid.
• Power.
• Smart grid.

Comments

[edit] It would be good to define the scope of EUI and whether renewables are or are not included. LETI's definition within the Climate Emergency Design Guide excludes energy consumption from on-site renewable energy generation which differs from RIBA's Operational Energy targets which include energy consumption from renewable energy generation and LETI's subsequent FAQs on Net Zero. There is risk of relying solely on metrics which exclude on-site renewable generation as it can mask the poor performance of building fabric and operation.

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