Senator BIRMINGHAM (South Australia) (14:30): I have a further supplementary question, Mr President. Given the minister has only been able to highlight measures that energy suppliers have described as seriously deficient, is the minister concerned about the uncertainty that is being generated by the carbon tax? How is this uncertainty surrounding electricity reliability impacting on business confidence and therefore business investment in the economy at present? Isn't the very threat of Labor's carbon tax plan already casting a dark shadow over the Australian economy?