Sun Microsystems will officially unveil its $1 per CPU hour grid later this week, the company's president Jonathan Schwartz has announced on his blog. 

But the service will initially be limited to the US and is expected to hold less capacity than promised.

Sun officially unveiled its grid in February last year designed to provide enterprises with access to computing power in a similar way to electricity.

The offering targeted compute intensive tasks such as rendering animations or running a financial model or analysis.

Sun later delayed the roll out, claiming that large clients were soaking up all the capacity. This left no space for the so-called 'retail' offering, where anybody would be able to purchase computing power at $1 per CPU hour from a special website.

Gordon Haff, an industry analyst at Illuminata, told vnunet.com at the time that Sun needed additional time to sort out security issues, such as preventing it from being used to send spam or launch denial of service attacks.

Schwartz blamed the delay on the reluctance of enterprises to put their trust in grid systems. Instead they preferred the traditional outsourcing model where a provider comes in and takes over the management and maintenance of a data centre.

"But that would be like an electricity company collecting generators and unique power requirements, and trying to build a grid out of them," he quipped.

Schwartz also acknowledged that building the Sun grid proved to be more complex than initially thought.

Most of today's grids are built for specific applications such as data analysis, powering online search engines or video rendering, but Sun's general purpose grid required a different approach.

A security audit raised a number of problems that required repairing, and the US government wanted to make sure that the service would adhere to export controls that keep certain technologies out of the reach of "rogue nations".

The export controls will initially limit the grid to the US, but Schwartz promised that Sun still plans to make the service available globally.

Applicants registering for an account will be screened before they are granted access.

Once the service is live, users will be able to sign up and access their accounts through the network.com website.