Answer: Limitations of the Conventional Sources:-Energy consumption has been increased dramatically over last two decades and all the requirements have been fulfilled by the so-called conventional sources or the non-renewable sources of energy. Some of the limitations of using these sources are given below: 

1. Exhaustability:- These resources are available in limited amount and have developed over a very long period of time, But with the vast expansion of the industrial and the agricultural development globally these resources will ultimately be exhausted

2. Increased demand:-The supply on a daily basis of fossil fuels such as oil or gas will fail to meet the increasing demands and will ultimately lead to a hike in the price by 50%. The starters levels of consumption in real terms will over burden the natural capacity of the Earth's production of these additional amounts would be constraints which will hasten this shortage, thereby reducing the time available for application on the alternatives. 

3.Pollution:-Besides the shortage of these resources in the near firm, the major drawback in using these exhaustible resources is the pollution problem arising from their use. As our energy needs are increasing, we are burning more and more fuels and these increased uses of the fuels is adding more undesirable and poisonous chemical pollutants in the air.

Most of the air pollution occurs due to the products of the combustion of various types of fuels like coal, wood, petrol, diesel, and kerosene.

4. Climate change:- The burning of fossil fuels release various gases like carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen dioxide et cetera. which upsets our climate patterns by bringing out the undesirable changes in the climate.

Various surveys conducted show that the concentration of the carbon dioxide in the atmosphere has increased by a quarter in the last century leading to the increase in the avenge ambient temperature.

And the rise in even a degme can pose a threat to the overall balance of nature as it will lead to the warming of the oceans and melting of polar ice caps, thereby causing sea levels to rise resulting in floods in the coastlands. This is called global warming

5. Destruction of life and property:- Use of fossil fuels results in scarred landscapes, oil spills, polluted waterways, acid rain and smog.