Comment by OtherShrezzing

Drax uses about 12,000km^2, not 160,000km^2.

A slightly more useful land area is the United Kingdom itself, which is 243,000km^2. With this technique, it takes an area 1/19th the size of the UK to produce 4% of its energy.

This isn't a feasible approach to energy production, but it's an order of magnitude less bad than your figures have put forward.