Smart grid's global reach is expected to draw spending in excess of $46.4 billion by 2015, a report said Monday.

Smart metering of electricity consumption, pioneered in North America and Europe, has caught on worldwide and the latest estimates put annual shipments of smart meters for new installations at more than 140 million units.

Electricity suppliers are especially keen on smart meters because the appliance and networks give the companies greater control on consumers.

At the same time, skepticism has centered on security risks in putting electricity supplies in whole grids at the mercy of centralized computer controls.

IDC Energy, in its "Worldwide Utility Smart Grid Spending Forecast, 2010-2015," said smart grid spending on hardware, software and services will increase 17.4 percent globally from 2010-15 while overall spending will reach $46.4 billion worldwide by 2015.

Although smart grid operations first took root in North America and Europe, most growth in the coming years is likely to be in the Asia-Pacific region.

China aims to deploy 300 million smart meters by 2020.

Growth in smart grid development in that region is likely to exceed 33.7 percent during the period.

The report identified 14 smart grid project types to identify top investment priorities across regions, saying they differed from region to region and growth trends also depended on whether a grid was state-run or investor-controlled.

Utility investments in smart grid initiatives are intended to improve grid reliability, support distributed and renewable energy, reduce operations and maintenance costs, increase energy delivery efficiency, improve system security and enable energy efficiency and demand response, says the report.

Current trends indicate most smart grid installations in four regions -- North America, Europe, Asia-Pacific and Latin America.

Africa continues to lag, partly because vast areas on the continent lack basic electrification.

Smart grid had its North American beginnings in Austin, Texas, in 2003 and a European debut in Italy in 2005, after the launch of a commercial scale project by Enel S.p.A.

Despite the spread of the computerized system it is by no means clear if the various smart grid infrastructures will be compatible or competitive.

Smart grid suppliers say the consumer stands to be benefit from the development as the digitally enabled system allows for constant communication between the supplier and the user.

The system gathers, distributes and acts on information about the behavior of all suppliers and users in order to improve the efficiency, importance, reliability, economics and sustainability of electricity services.

Critics say the smart grid system is more open to abuse, even terrorism, than conventional grids and in some instances may be more intrusive than the systems it aims to replace.