That number didn’t really seem enough to me. However, the solar luminosity is about 3.8×10^26 watts and the surface area about 6.1×10^18 m2, ie. 62.3 MW / m2. 8760 hours in a year times 62300 kW equals 545 million kW/h, at twenty percent efficiency times twenty cents each is $21.8 M/a.
The sun might seem to be really, really hot; but in fact, it is just quite hot and really, really big.