Dec 13 (Reuters) - UK energy regulator Ofgem on Monday said it is inviting bids to build more cross-border electricity transmission connections including pilot projects connecting offshore wind farms in the North Sea. Britain is seeking to increase the amount of low-carbon electricity it can import to replace lost capacity as older coal and nuclear power plants close, and to help meet its climate targets. "Ofgem is inviting bids to bring forward billions of pounds of investment in new electricity interconnectors to help boost energy security, hit the country’s climate goals, and save money for energy consumers," it said in a statement, without giving further figures. The regulator will hold a third investment round next year to build new subsea cables, called interconnectors, which can import cheaper clean energy when it"s needed and export surplus power to neighbouring countries, it added. Britain wants to more than double its existing cross-border connection capacity by 2030 to support quadrupling offshore wind capacity by the same date, Ofgem said, adding the new investment round would favour projects that could complete by that date. For the first time, Ofgem will also seek bids for "Multiple-purpose Interconnectors" (MPIs) which can link up clusters of offshore wind farms directly to an interconnector, delivering power to more than one country, it added. At present, Britain is connected to Ireland, France, Belgium, the Netherlands and Norway via seven cables, providing almost 7% of the UK"s electricity last year, the regulator said. Investments will be made under Ofgem"s "cap and floor" regime, with sets both a floor and ceiling for revenue to ensure adequate investor returns while keeping costs down for consumers. The British government on Monday also launched a new auction round for renewable capacity. read more