Impacts of Renewable Energy Resources

Renewable does not mean impact-free

Hydro-electric power (HEP), wind power and solar power use naturally replenished sources: moving water, wind and sunlight. Unlike burning a finite stock of coal or oil, using these resources does not exhaust a fuel supply.

Developing them means constructing equipment and infrastructure to generate electricity. This can bring jobs and useful energy, but it also changes places where people live and wildlife depends on habitats. The impacts therefore include both benefits and costs for people and the environment.

An important distinction is between construction and operation. HEP stations, wind turbines and solar panels produce few greenhouse gas emissions while generating electricity. However, manufacturing materials, transporting equipment and building installations produce carbon dioxide. Their environmental benefits do not mean that their whole development is emission-free.

Hydro-electric power: electricity from stored water

A dam can be built across a river to hold back water, forming a reservoir. Water released through the dam turns turbines connected to generators, producing electricity. The development involves more than the power station itself: land behind the dam is flooded to create the reservoir.

For people, a reservoir may become a place for tourism and recreation, creating jobs and income. However, people living on land that will be flooded may have to relocate. Losing a home and leaving an established community is a very different experience from gaining a tourism job, so benefits are not shared equally.

For the environment, HEP provides electricity with few greenhouse gas emissions once built. Against this benefit, dam construction and reservoir flooding can destroy habitats and ecosystems. A dam also interrupts the river: it can prevent fish moving upstream and trap sediment that would otherwise travel downstream, affecting river ecosystems. Construction itself produces carbon dioxide emissions.

This creates a trade-off between continuing electricity generation and major changes to the river valley. A reservoir's tourism benefits do not remove the losses experienced by displaced residents or wildlife.

Wind power: useful energy with local impacts

Wind turbines use moving air to turn blades connected to a generator. Developing wind power involves manufacturing and installing turbines; grouping them into wind farms allows significant amounts of electricity to be generated.

Building and maintaining turbines creates jobs. Once operating, they generate electricity with few greenhouse gas emissions. However, their output depends on the wind: a resource can be renewable without supplying electricity whenever it is needed.

Nearby residents may experience noise, and some people consider turbines visually intrusive. These impacts affect the quality of the local environment even though the electricity has wider benefits. Turbines can also affect bird migration patterns, and birds may be killed by collisions with moving blades. Manufacturing and constructing the turbines produces carbon dioxide.

Wind power therefore combines a wider low-emission electricity benefit with impacts concentrated around the development. Its overall value depends partly on whether its location avoids particularly damaging effects on residents and birds.

Solar power: electricity and competition for land

Solar power is developed by manufacturing and installing panels that convert sunlight into electricity. Making and maintaining panels creates jobs, while electricity generation produces few greenhouse gas emissions once the panels are installed.

Large solar developments can occupy farmland. This creates competition between using land to generate electricity and using it to grow crops. The same development may provide energy and employment while reducing the land available for farming.

Manufacturing panels also generates carbon dioxide emissions. Some panels contain toxic metals that may harm the environment if released, so the materials used in the equipment matter as well as its operation. Solar power's low operational emissions should therefore be weighed against land-use impacts and the environmental costs of manufacturing.

Reaching a balanced assessment

Assessing renewable energy means deciding how significant the benefits and costs are, rather than simply counting them. Compare their scale, duration and distribution. Low-emission electricity can benefit many people over time, whereas habitat destruction or relocation may have severe, lasting effects in a particular place.

For example, HEP may provide electricity and tourism opportunities, but flooding a populated valley could impose substantial social and environmental costs. Wind avoids creating a reservoir, but can still disturb residents and birds. Solar has few emissions during operation, yet occupying productive farmland creates a different trade-off.

A supported overall judgement is that renewable development can provide valuable electricity with low operational emissions, but no resource is automatically harmless. The resource chosen, the location and the severity of local impacts determine whether its benefits outweigh its costs.