A negawatt market is a proposed idea of implementation of the demand response (balancing the electrical grid through the changes in consumption) that uses an energy market where the commodity traded is a negawatt-hour, a unit of energy saved as a direct result of energy conservation measures. Negawatt power is investment to reduce electricity consumption rather than investing to increase supply capacity. In this way investing in negawatts can be considered as an alternative to a new power station and the costs and environmental concerns can be compared. Negawatt investment alternatives to reduce consumption by improving efficiency include: Improved thermal insulation and airtightness for buildings – low environmental impact Replacing older industrial plant – low environmental impact. Can have a positive impact due to reduced emissions. Negawatt investment alternatives to reduce peak electrical load by time shifting demand include: Storage heaters – older systems had asbestos. Newer systems have low environmental impact. Demand response control systems where the electricity board can control certain customer loads – minimal environmental impact Thermal storage systems such as ice storage systems to make ice during the night and store it to use it for air conditioning during the day – minimal environmental impact Pumped storage hydroelectricity – can have a significant environmental impact – see Hydroelectricity other Grid energy storage technologies – impact varies Note that time shifting does not reduce total energy consumed or system efficiency; however, it can be used to avoid the need to build a new power station to cope with a peak load. Origin and development A negawatt-hour is a unit of energy saved as a direct result of energy conservation measures, such as reducing the use of heat or electricity. The concept was developed after Amory Lovins authored an article published in the March 21, 1985 issue of Public Utilities Fortnightly arguing that utility companies will sell less electricity and more efficiency by marketing 'negawatts'. In Lovins' opinion, utility customers don’t want kilowatt-hours of electricity; they want energy services such as hot showers, cold beer, lit rooms, and spinning shafts, which can come more cheaply if electricity is used more efficiently. Lovins credited the term to a typo in a document by the Colorado Public Utilities Commission in which the word "megawatt" was misspelled. Negawatts are a form of encouragement to motivate consumers to conserve energy. Lovins considers the concept of conservation "a change in behavior based on