OSLO, June 10 (Reuters) - Britain's National Energy System Operator (NESO) has issued offers for electricity grid connections to more than 700 projects accounting for 58% of those in the pipeline until 2030 under an overhauled connection regime, it said on Wednesday.

o Offers have been made to 713 of the 1,223 projects in the 2030 pipeline, including offshore and onshore wind, solar, battery storage, gas and hydro, together totalling 37 gigawatts (GW).

o The offers set out when and where projects can connect and what network upgrades are needed, giving developers the certainty they need to  move forward, NESO said.

o Recent reforms replaced a 'first come, first served' system that led to bottlenecks and delays for ready-to-go projects.

o In total, the projects supported by this process could help unlock up to £40 billion of annual clean energy investment, the NESO statement said.

o To support grid connections, thousands of kilometres of new electricity lines and cables are also  required.

(Reporting by Nora Buli; Editing by Kate Mayberry)