Electricity generation, transmission and distribution system are a vital infrastructure & play an important role for the entire world. During the last decades substantial changes has taken place in the electricity distribution sector worldwide to make the system reliable and to provide electricity to all the households. The balancing of such system taking into account of environmental & social impact is very crucial for us because it directly impact on all living and non-living objects surrounding us in the environment. Although electricity is a clean and relatively safe form of energy when it is used and play an important role to meet our needs which only can be fulfill by electricity, the generation and transmission of electricity affects the environment. Nearly all types of electric power plants have an effect on the environment, but some power plants have larger effects than others. Electricity transmission lines and the distribution infrastructure that carries electricity from power plants to customers also have environmental effects. Most transmission lines are above ground on large towers. The towers and power lines alter the visual landscape, especially when they pass through undeveloped areas. Vegetation near power lines may be disturbed and may have to be continually managed to keep it away from the power lines. These activities can affect native plant populations and wildlife. Power lines can be placed underground, but it is a more expensive option and usually not done outside of urban areas but in that case an economical option may be to bury.
The development of High Voltage Transmission System (HVTS), Extra high voltage (EHV) System usually effects wide array of environmental and social impacts like displacement of local people affecting their livelihood, electro-magnetic radiation leading to serious health complications as well as change in agricultural yield besides impacting various other health and safety risks depending on existing land use pattern of the project area.
Energy losses during transmission & distribution cause indirect carbon emissions and air pollution in power generation plants which vary with the type of primary energy source.
Crops which is steep may get damaged and farmer may not able to cultivate the land since construction activities may continue for a short to medium term duration depending the pace of work, clearances etc. Impact on public properties and the RoW (Right of Way) of the transmission & distribution line being selected avoiding impact on common properties such as schools, religious places, water bodies, and access roads etc., specially the proposed transmission line should not intersect any village settlement and also should not pass through any urban establishment in the entire stretch.
Environmental & Social awareness/assessment is very important to determine the environmental and social impacts and risks of any developmental project. It is the most useful tool for understanding and managing the enviro-social impacts of a project and to integrate these environmental impacts into the cost-benefit evaluation in order to avoid decisions that may be biased towards less environment friendly solutions. The construction and maintenance of transmission line rights-of way, especially those aligned through forested areas may result in alteration and disruption to terrestrial habitat, including Impacts to species and an increased risk of forest fires. These impacts can be minimized by careful route selection. To ensure that the implementation of the project with provide information about scope of adverse E&S risks and impacts expected during project construction and operation; describe the approach to mitigation and Monitoring actions to be taken. Project implementation with an Environmental &Social screening process and risk management that will enable them to identify, assess and mitigate potential E&S impacts of project activities, including through the preparation of a site-specific Environmental and Social Impact assessments (ESIA) and/ or Environmental and Social Management may reduce the several causes and impacts in environment.
Installing distribution lines underground protects trimming trees, damage from vehicles, and most lightning strikes. However, the cost can be prohibitive more than that of overhead distribution—and does not ensure 100% reliability. For example, severe storms may also bring flooding which can damage cables and supply may interrupt. For underground facilities, once the water recedes, troubleshooting and restoration may actually take longer than with overhead distribution systems. Such targeted undergrounding can be an effective hardening investment strategy. Understanding that restoration time is related to accessibility, it may be most cost-effective to use undergrounding for portions of a circuit that are harder to access. But keeping in view of environmental impact economical option may be to bury for selected portions of the system. Tree trimming is fundamental for mitigating local distribution outages. Recently, utilities have effectively used the results of storm damage and subsequent restoration in assessing vegetation management and tree trimming programs by facilitating regulatory enforcement of tree trimming rights which can make a smile on our faces.
Environmental hazards emerging from distribution companies are mainly related to pollution (e.g. emissions of oil from oil-filled components, SF6-gas leakages, poor waste management disposal etc). Visual pollution – e.g. from overhead lines crossing through nature - is also a factor, together with electric and magnetic fields emerging from distribution system components. Another potential environmental risk aspect is that pollution-abatement equipment such as pumps and filters often depend on electricity. Environmental risk related to generation, transmission & distribution system components can both have a local impact, affecting the sites being close to the scene of the incident / accident, and a global impact.
Environmental monitoring programs for this sector should be implemented to address all activities that have been identified to have potentially significant impacts on the environment during normal operations and upset conditions. Environmental monitoring activities should be based on direct or indirect indicators of emissions, effluents, and resource use applicable to the particular project. However in transmission projects it is being carried out but assessment should also be implemented in distribution system.
In next article we will discuss the detailed environmental impacts due to power distribution & Transmission and what can be the approaches to reduce the impacts.