Three Gorges Dam – Positive and Negative Externalities

Below is a very good documentary on the construction of the largest dam in the world – the Three Gorges Dam in China. However in its construction there are both costs and benefits including private and external. This is a topic in Unit 3 of the CIE A2 Economics syllabus and is found under – Externalities. Remember that we have both positive and negative externalities of production and consumption.

THE DIFFERENCE BETWEEN PRIVATE AND SOCIAL COSTS

 Externalities create a divergence between the private and social costs of production.

SOCIAL COST = PRIVATE COST + EXTERNAL COST (externality)
  • Private costs are the costs to a ‘firm of producing a good or service and to an individual of consuming a product.
  • External costs are the spill over effects on third parties.
  • Social costs are obtained by adding the private and external costs together. They reflect the total cost to society of an economic decision.

The same concept applies for Private and Social Benefits:

SOCIAL BENEFIT = PRIVATE BENEFIT + EXTERNAL BENEFIT (externality)

Benefits and Costs of building the Three Gorges Dam

Three Gorges dam - Externalities

The biggest benefit that is seen from the dam’s construction is that it produces renewable energy from hydro electricity. The Three Gorges Dam alone can provide China with 10% of its annual energy consumption. Increasing the proportion of hydroelectricity alternative to coal burning plants, will cut their emissions greatly which will help reduce the overall emissions all over the world – carbon emissions will be reduced 100 million tonnes compared to alternative coal generation

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