Backgrounder: New energy, clean energy, renewable energy

BEIJING, Nov. 30 (Xinhua) -- Many countries have been developing new energy to curb greenhouse gas emissions and fight climate change, while buzzwords such as clean energy, green energy and renewable energy receive much publicity.

New energy is a concept that is contrary to traditional fossil fuels such as oil, natural gas and coal. In addition to renewable energy sources such as solar, wind and biomass power, new energy sources also include nuclear power.

As a non-renewable energy source, nuclear energy almost produces no pollution. But it consumes uranium fuel and produces nuclear waste. The development of nuclear energy also requires big investment. Yet it is a good alternative to fossil fuels as the world is striving to curb carbon dioxide emissions.

Clean energy, or green energy, refers to those energy sources that cause no pollution. As nuclear energy almost produces no pollution, some experts also classify it as a kind of clean energy source.

A similar concept is renewable energy, which is generated from renewable natural resources such as water, sunlight, wind, methane gas, geothermal heat and tidal waves.

As renewable energy is naturally replenished, many countries prioritize the development of this category. However, renewable energy relies much on natural conditions and requires heavy investment and high maintenance cost. Its energy efficiency is also relatively low.

Currently, many scientists are searching ways to boost the efficiency of renewable energy to improve the energy mix in a world where the problem of natural resource shortage is looming large.