You can always use the othe rmethod of rendering. Once you decide your laptop has been on for long enough, you pause the render, keeping TG2 and the render screen open, then put your PC into standby mode. When you start it up again from stand-by mode, everything is sitting exactly as you left it and you can continue the render from where you left off.
I'd love to see a full-size version of that render (hint-hint)