Electricity supplied through the mains or grid network will be primarily used for indoor events. Some outdoor events may have access to mains outlets, and it is preferable to use this than portable diesel generators.

Sources of mains supply include:

Traditional Power Generation

Traditional dirty methods of mass power production use coal, gas, fuel oil and uranium. Apart from the obvious greenhouse gases from combusting fossil fuels, there are also the compounding effects of mining the non renewable resources and full range of environmental impacts, along with transportation of the raw materials.

Fossil Fuels
Coal, oil and gas are combusted to produce electricity. One of the dirtiest forms of electricity supply with high levels of greenhouse gas emissions.

Nuclear
A controversial energy source, due to the radioactivity of fuel used and waste produced.  Recent events in Japan further support those who see nuclear as a problematic solution to energy supply.

Renewable Power Generation

Rather than combusting ancient ‘carbon’ – ie fossil fuels (oil, coal, gas) or using dangerous nuclear power, it is possible to generate mains electricity from zero emissions sources or renewable options, that still produce GHG emissions but are combusting ‘recent’ carbon rather than unlocking ancient fossil fuels.

Large Scale Hydro
Viewed as a renewable energy supply, and certainly zero emissions. This option is brings up controversy when biodiversity/habitat/ecology issues arise from reclamation of land for dams. There may also be downstream impacts on waterways and ecosystem. Additionally displacement of people who have traditionally inhabited areas where dams will go or whose lives and livelihoods may be affected by downstream impacts of damming are considerations.

Wind
Harnessing the power of wind is a truly zero emissions source of energy supply. This option has been enthusiastically taken up by many countries and regions. Controversly lays in landscape/views interruptions.

Solar
Harnessing the power of the sun is also a truly zero emissions source of energy supply. This option is also being enthusiastically taken up by governments and private ventures.

Geothermal
This is harnessing the energy from heat generated naturally within the earth. This option is gaining popularity and is only really viable at locations where access is possible.

Biomass
Combusting biological matter is viewed as a renewable form of energy. Greenhouse gases are still emitted during combustion, but it is the combustion of 'recent' carbon rather than ancient fossil fuels. This can be through incineration where heat from burning is used to turn water into steam to drive electricity turbines. Other options include gasification/pyrolysis where biomass is turned into gas in the absence of oxygen, this is then combusted to produce electricity. Methane extraction from landfills (biogas) and gas from anaerobic digestions are also combusted to create electricity.

Micro Generation/Combined Heat & Power
In a ‘Combined Heat and Power’ (CHP) system both heat and power are produced from a single process. Losses of energy through unused heat and transmitting electricity out to the customer via the grid make traditional centralized power plants inefficient in comparison to CHP. In a CHP system the recovered heat is distributed to the immediate surrounding areas and used for hot water, space heating, or the steam can be used for industrial purposes.