What are the similarities between solar and coal energy?

Solar energy originates with the Sun. It can be captured by plants and other producers for the process of photosynthesis. As a result of this process, solar energy is converted to chemical energy in the form of glucose molecules. Glucose can be in turn eaten by herbivores and these organisms can be eaten by other organisms in a food chain. When an organism dies, bacteria and fungi known as decomposers, consume dead organisms and obtain energy.  All of this energy is indirectly from the Sun. 

Coal is formed from the remains of ancient trees that lived in the Carboniferous era. It was hot and they lived in a swampy environment. Through burial and compression over time, the remains of these ancient trees became coal. Coal contains stored chemical energy and this energy originally came from solar energy that kept these ancient trees alive.

What is really occurring here is the process of energy transformation. Energy cannot be created or destroyed but it can be transformed from one form to another. Solar energy is transformed to chemical energy in plants and this energy can be eaten as seen in a food chain, or it can be used to heat a home as seen in power plants which use coal's stored chemical energy to generate electricity. This shows the relationship between solar and coal energy.

I have included a link which has a virtual lab showing energy transformations and another that has a diagram illustrating the same concept.