Energy Efficiency
Energy efficiency is the goal of efforts to reduce the amount of energy required to provide products and services. An example would be installing fluorescent light bulbs because they reduce the amount of energy required to attain the same illumination as regular incandescent light bulbs. Compact fluorescent light bulbs use 2/3 less energy and may last 6 to 10 times longer than incandescent light bulbs. Improvements in energy efficiency are most often achieved by the use of more efficient technology or production process.
There are various motivations to improve energy efficiency. Reducing the energy cost may result in a financial cost saving for consumers. Reducing energy use is also a key solution in reducing carbon emissions.
What is a Carbon Footprint?
A carbon footprint is a measure of the impact that our activities have on the environment, and in particular climate change. The carbon footprint is also a measurement of all the greenhouse gases an individual produces. A carbon footprint is made up of two parts, the primary and a secondary footprint. The primary footprint is a measure of our direct emissions of CO2 from the burning of fossil fuels. The secondary footprint is a measure of the indirect CO2 emissions from the whole life cycle of products we use.
The figure above shows the main elements which make up the total carbon footprint of a typical person who lives in a developed country.
Embodied Energy
Embodied energy is defined as the sum of energy inputs that was used in the work to make any product, from the point of extraction and refining materials, bringing it to market , and disposal or re-use of the product.
The figure above shows the embodied energy of certain building materials. Concrete is at the bottom of the list because it requires a lot of energy to be made while an aluminum sheet has high energy output.