100 words min for problem 1 and problem 2, answer every part of each problem, no cut and paste, no wiki, cite all refs

1. Assume that you are to estimate the costs of either:

A project proposal to construct a dam in your local area for hydroelectric power generation.

A policy to regulate emissions from Sport Utility Vehicles.

A policy to ban offshore drilling in the Gulf of Mexico.

There are several environmental implications involved. Identify as many of the costs of these proposed policies or projects as you can.
Classify the costs as either explicit or implicit costs.
What cost estimation technique would you use to estimate the costs identified?
Which costs would be difficult to estimate?