What are the social factors in using solar energy?

Factors that have prevented us from using nuclear fusion as a controlled energy source?

• Answer:

  Basically because it is a much more difficult thing to achieve than nuclear fission. So far the best experiments have only achieved fusion for a fraction of a second. A new rig called ITER is planned as the next step, and should achieve a lot more, but we will still be a long way from a useful power producing plant. Wait another 50 years and ask again!