There is no limit to how much solar energy the world can harvest. The sun is there, always, and it is shared equally with everyone. The sun is a way that people can always have energy without needing to refine it. There is also limited pollution, and less risk of injury to animals than there are from wind farms.
Yes, solar is a practical source of energy on both large and small scales. After setting up basic infrastructure, there is a regular source of energy to use for basic everyday use. The fact that India is the first to use solar on a large scale should be a wake-up call for the U.S. and other industrial countries.
Solar energy is readily available and becoming more cost-effective with each passing year. It is quiet and does not come with some of the complications associated with other energy sources. There is no pollution and little impact on surrounding areas. Solar is already used on a large scale for some schools and industries.
In countries such as India which have consistently high levels of sunshine throughout the entire year, solar power is a reliable and environmentally sound power source that should be cultivated on a large scale. However, this may not be practical for every country in the world as many do not have the same climate advantages as India.