Solar energy is a renewable energy source. This means that we cannot run out of solar energy, as opposed to non-renewable energy sources (e.g. fossil fuels, coal and nuclear). We will have access to solar energy for as long as the sun is alive - another 6.5 billion years according to NASA[1]. We have worse things to worry about; in fact, scientists have estimated that the sun itself will swallow Earth 5 billion years from now