Why The Some Of Energies Is Coverting Into Electrical Energy

Why is it hard to convert heat into electrical or any other form of energy?

The problem is the second law of thermodynamics. Every form of energy has an associated entropy (or degree of randomness). So when converting from one form to another there will be a natural tendency to convert to a form with higher entropy. So for every form of energy there is a efficiency limit which tells what is the maximum useful energy that can be extracted based on the 2nd law. This is also referred to as Exergy. Electricity is a form of energy with highest exergy (lowest entropy), So electricity can be converted to almost any other form of energy at very high efficiencies. On the other hand heat is an energy with very high entropy and low exergy (Also lower temperature = higher entropy), therefore it is so inefficient to convert it to something like electricity.Just as an analogy: Imagine a bunch of people moving (just like gas molecules). If every one is moving in coherence, then a lot of energy can be extracted (this is the case of very low randomness or high exergy) on the other hand if everyone is moving randomly it becomes very difficult to extract any energy (case of high randomness or low exergy)

What are the different forms of energy to which electrical energy can be converted?

I know of only the following:Light - BulbSound - SpeakersKinetic energy - MotorsChemical - charging batteryHeat - heatersPotential energy - pumping water overhead

Why do we use electrical energy instead of alternative forms of energy?

Both earlier answers are very correct.Having said that, the question still remains partially answered.Electricity by itself is of no direct use to us. It is useful only when converted to some other type of energy-Running of motors or machines, unning of cars or buses or trains ( all forms of mechanical energy ),LightingIndustrial processes and productionElectrolysis, plating etc.- chemical energyRadio, TV, telephone- sound and light visionCooking, ironing, heatingAnd others you may think of.Again, you are using solar energy directly first water heating, industrial heating and ovens, Cooking and others.Diesel pumps and cars do not use electrical energy for running. We had steam engines for railways.If you look around, you can come across several applications of other forms of energies being used.Again, each of these energies is in turn useful by its physical culmination for a purpose.