Such an exchange would allow companies to buy relatively cheap IT resources as and when they need it, at market prices.
The demand is likely to come from firms that want to carry out large-scale financial analyses or geophysical modelling.
The electronic marketplace could be operational in three to five months and be worth £2bn in a short period of time, said Sun, which also announced last week it will sell computing resources at $1 an hour.
Analyst group Ovum said these predictions were optimistic. "For the next two years at least, the vast majority of utility computing users are wrestling with the task of becoming 'utility ready'. It will be a long time before the notion of computer exchanges becomes anything more than a niche," research director Gary Barnett said.