Grid-tied electrical system
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A grid-tied electrical system, also called tied to grid or grid tie system, is a semi-autonomous electrical generation or grid energy storage system which links to the mains to feed excess capacity back to the local mains electrical grid. When insufficient electricity is generated, or the batteries are not fully charged, electricity drawn from the mains grid can make up the shortfall.
When batteries are used to store, the system is called battery-to-grid (B2G), which includes vehicle-to-grid (V2G).
How it works
Direct Current (DC) electricity is passed to an inverter which is grid tied. The inverter monitors the alternating current mains supply waveforms and generates electricity that is phase matched. The DC electrical system is attached to the mains via this mechanism.
Because the local system is phase matched, electricity can be drawn from the mains in the situation of a generating shortfall or discharge in batteries.
When phase matching does not occur, most inverter (s), via software controls, tailored to end user application, courtesy power access is possible when the grid goes down. Power scavenging software via monolithic devices can be made operational when the grid fails to accept the power being continuously provided to the grid but rejected --essentially a "black out". When the sun shines, power can be made, grid-tied electrical systems can potentially maximize upon this effect when tethered to other "net-metered" entities, such as the Internet.
Quality of service
A key concept of this system is the possibility of creating an electrical micro-system that is not dependent on the grid-tie to provide the high level of service quality which is often delivered by a traditional mains supply.
Conversely if the mains supply of the region is unreliable, the local generation system can be used to power important equipment.
Local generation can be from an environmentally friendly source such as photovoltaic. Individuals can choose to install their own system if an environmentally friendly mains provider is not available in their location.
Small scale start
A micro generation facility can be started with a very small system such as a home wind power generation or photovoltaic (solar cells) generation system.
Sell to and buy from mains
- Excess electricity can be sold to mains.
- Electrical shortfall can be bought from mains.
List of countries or regions that legally allow grid-tied electrical systems
- Bosnia and Herzegovina
- Dominican Republic
- European Union
- New Zealand
- Philippines (via MERALCO)
- South Africa (Only by arrangement with municipality)
- Sri Lanka
- United States of America
- Venezuela (actually there are no legal restrictions)
- Cost of electricity by source
- Distributed network
- Electric power transmission
- Grid energy storage
- Grid tie inverter
- List of energy storage projects
- Power outage
- "Directive 2001/77/EC"
- "Public Utility Authority" Photo-voltaic guidelines
- "Official Newspaper of the Federation of Mexico" Contract of Interconnection of Photovoltaic Systems updated 27 June 2007 (Spanish)
- "Federal Commission of Electricity" Renewable Energy guidelines updated 3 September 2010 (Spanish)
- "Energy Market Authority of Singapore": "Handbook for Photo-voltaic (PV) Systems" updated 10 September 2007