Anyone know how to reduce voltage but still provide suitable current.

A friend needs to reduce 24v DC to 12v DC, but needs to drive a load of around 250mA. Whilst voltage dividers work well at providing a reference voltage, they appear impractical when you place a load across (ie in parallel with) the second resistor.

Using a 12v regulator is also impractical for him as the heat generated to dissipate 12V means it requires a large heatsink.