1. they can commonly used for a long time 2. Are generally exhaustive 3. Are mostly polluting . 4. example - firewood, coal ...

Conventional sources of energy refer to the traditional and widely used sources of energy that have been in use for many years. These include:

1. Fossil Fuels: The most common conventional sources of energy are fossil fuels, such as coal, oil, and natural gas. These fuels are formed from the remains of plants and animals over millions of years and are burned to release energy.

2. Nuclear Power: Nuclear power involves the use of nuclear reactions, specifically nuclear fission, to generate heat and electricity. It utilizes radioactive materials, such as uranium and plutonium, to generate energy.

3. Hydropower: Hydropower harnesses the energy of moving water, such as rivers or waterfalls, to generate electricity. It is one of the oldest and most widely used renewable energy sources.

4. Biomass: Biomass energy involves the use of organic materials, such as wood, agricultural waste, or dedicated energy crops, to produce heat or electricity. It can be burned directly or converted into biofuels.

5. Natural Gas: Natural gas is a fossil fuel that primarily consists of methane. It is often used for heating, cooking, and electricity generation.

Non-conventional sources of energy, also known as alternative or renewable sources, include:

1. Solar Power: Solar energy utilizes sunlight to generate electricity through photovoltaic (PV) cells or concentrated solar power (CSP) systems.

2. Wind Power: Wind energy converts the kinetic energy of wind into electrical energy using wind turbines. It is one of the fastest-growing sources of renewable energy.

3. Geothermal Energy: Geothermal energy harnesses the heat from the Earth's core to generate electricity or provide heating and cooling.

4. Tidal Energy: Tidal energy captures the kinetic energy of tides and converts it into electricity through tidal turbines.

5. Wave Energy: Wave energy captures the energy of ocean waves and converts it into electricity using wave energy converters.

6. Hydrogen Fuel Cells: Hydrogen fuel cells convert hydrogen gas into electricity through an electrochemical reaction, offering a clean and efficient energy source.

Mineral energy sources, on the other hand, refer to the various minerals and metals that are used in the production of energy technologies. These include minerals like lithium, cobalt, and rare earth elements, which are crucial for the production of batteries, solar cells, wind turbines, and other renewable energy technologies.