Switzerland and a handful of countries in Europe led the way in a global ranking Tuesday of energy efficiency, access to resources and environmental sustainability.

China ranked 78th and the United States was 15th, according to the report by the World Energy Council, a London-based group that promotes sustainable power.

Canada came in sixth and France was 10th, while the worst showing of all 129 countries was made by Zimbabwe.

Countries were also given letter grades for their performance in three categories: how well they manage their energy supply, how accessible and affordable energy is across the population, and how much of their power is derived from low-carbon renewables.

Only five countries received all A's -- Switzerland, Denmark, Sweden, Britain and Spain.

Benin and Zimbabwe received all D's. India, Lebanon, Yemen and Nicaragua also fared poorly with C's and D's.

China got an A for energy security but D's for the environment and affordability and equitable access to power.

The United States was a top scorer in security and supply but earned a C in environmental friendliness.

The report was based on interviews with more than 50 government officials, development banks and international experts from more than 25 countries, the WEC said.

Policymakers interviewed for the report urged more proactive energy policies, and called on the energy industry to help developed countries makes strides toward sustainable energy.

The report was released three weeks ahead of talks at the World Energy Congress, to be held in Daegu, Korea.