Renewable Energy Sources

What percentage of the world's total energy is supplied by renewable energy sources?

What is the process by which green plants convert sunlight into plant material?

By what year could alternative energy sources provide half of the world's energy needs, according to some studies?

What is the main source of biomass energy in less-developed countries?

What is the competitive energy source with renewable energy sources?

What percentage of world energy consumption is accounted for by the 25 member countries of the Organization for Economic Cooperation and Development (OECD)?

What is the approximate percentage of conventional fossil fuels in the total energy consumption?

What is the primary factor determining energy use?

What are nonrenewable energy sources characterized by?

What was the effect of declining energy costs in North America and Europe during the 1980s?

What percentage of world energy consumption is accounted for by oil?

What is the primary source of renewable energy used worldwide?

What is the primary difference between a resource and a reserve?

What geological process transformed organic matter into coal?

What is the approximate percentage of global energy provided by renewable energy sources?

What is the primary environment in which plants accumulated to form coal?

What is the primary factor that affects the levels of fossil fuel reserves?