With regard to the procurement of energy from Independent Power Producers (IPPs), how many (a)(i) requests for prequalification (RFQ) and (ii) requests for proposal have been issued, (b) negotiations with preferred bidders are under way in terms of the regulations promulgated under section 35(4) of the Electricity Regulation Act, Act 4 of 2006 and (c) of these IPPs have applied to supply energy generated by renewable sources?