Scientists think that about 14 billion years ago (that is a 14 followed by 9 zeros), this universe came into being through the Big Bang. This is described in the Big Bang theory.

It is thought that, before the Big Bang, our universe had zero volume and must have consisted entirely of radiant energy with indefinite density of the energy and a temperature in the order of 1032°C (or 100,000,000,000,000,000,000,000,000,000,000).

Find out more about what is the Big Bang theory in this video.

After the Big Bang, the universe began to expand and cool and has done so ever since. Once the temperature had dropped to about 100,000°C, it was possible for protons and electrons to combine in pairs and create hydrogen atoms to then combine and form hydrogen molecules. Galaxies and stars started to form, including our own solar system with our Sun.

The Sun is the Earth’s power station. Every form of energy on Earth ultimately comes from the Sun. There are many ways that energy from the sunlight can be transformed, which demonstrates how much we rely on the Sun’s energy. The Sun’s energy drives the winds, the weather and movements of the oceans.

Plants rely on sunlight for energy, and animals get their energy either directly or indirectly from plants. Around 85% of the energy humans use comes from fossil fuels – remains of plants and animals that once used the Sun’s energy. Even hydroelectricity relies on the energy from the sunlight – if the Sun did not shine, all the water on Earth would be frozen and there wouldn’t be a water cycle driving the weather and movement of water.

Every living thing, without exception, depends on a source of energy to keep it living and reproducing. Sunlight provides the energy for green plants, and animals use the chemical energy in their food. All living things, except for subterranean microbes, are warmed directly or indirectly by the Sun’s radiant heat.

For all non-human animals, food and sunshine are the only sources of energy, but humans tap into a multitude of energy sources to convert ‘raw’ natural energy into energy for human use.

The first fuel used for heat, and maybe cooking, was wood around 200,000 years ago by Neanderthal man (Homo Neanderthalensis). Non-combustible energy sources – like geothermal heat, water for transportation or wind power in sails – may have been in use well before this.

Combustible fuels for early societies were wood, peat and dung, and sometimes oil, coal and natural gas. Combustion is a chemical reaction between the fuel and oxygen that releases heat energy. It can be either used directly for heating or it can be used to generate another kind of energy. A car, for example, converts heat energy into kinetic or moving energy.

Coal, oil and gas are collectively called fossil fuels because they were formed from the remains of plants or animals that lived hundreds of millions years ago. Although large amounts of these fossil fuels are found in underground rocks or at the surface, fossil fuels are limited and cannot be replaced.

This is why people are looking at alternative energy resources that are renewable and have less effect on our atmosphere by producing polluting greenhouse gases like CO2. Wind, water, solar and geothermal resources are renewable energy sources that humans have used for a long time. Lately, scientists have studied more closely how biomass – materials that come from living things – can be used effectively to lessen our need for fossil fuels.

Explore our resources to find out more about what will fuel our energy needs in the future, and whether it will involve oil or fuel produced from biomass. Hear and read about scientists, such as Peter Hall and Adam Vonk, who study oil resources and the type of biomass that could be used in New Zealand.


We have a number of activities and resources to use with your students when exploring future fuels.

Question bank

The Future fuels – question bank provides a list of questions about our energy options and places where their answers can be found. The questions support an inquiry approach.

Key terms

For explanations of key concepts, see Future fuels – key terms.


Use this timeline to explore how humans have relied on fossil fuels in the past and how we are looking for, and using, new energy sources.

Useful links

The 2014 Energy in New Zealand report from the Ministry of Business, Innovation and Employment.

Information paper from the Royal Society of New Zealand that discusses the potential for New Zealand to move towards a green economy.

    Published 10 June 2008, Updated 1 August 2014