Alternative Energy?

I’ve read reports that by 2030, 115 million barrels of oil need to be produced to the meet the increase needs of China and India.
This particular author advocated highly for alternative energies.
However, I read another source, where the argument was that alternative energies were just as harmful to the environment.
It is clear that the stifling need of fuels from over-populated India and China pose a large challenge, but is alternative energy the answer? Is there really enough oil to last us at least a century as some sources suggest? It’s difficult to get the truth from so many differing biases on our economy and fuel-usage.