Iberdrola started a €5 billion ($5.9 billion) capital increase, the biggest share sale in Europe so far this year, to bolster investments in power networks and further its US and UK expansion.The Spanish energy giant will carry out an accelerated bookbuilding offering, it said in a regulatory filing Wednesday. The company has set an indicative price guidance of €15.10 per share to market, according to terms seen by Bloomberg. Indicative investor interest exceeds of the size of the deal.The share sale will strengthen Iberdrola’s pivot toward power grids, which account for the bulk of the Bilbao-based company’s planned spending through 2026. The Spanish utility will maintain its focus on the US and UK, saying tariff frameworks for transmission and distribution activities in the two markets “represents an unprecedented investment opportunity.”The share sale will also result in total gross investment prospects of around €15 billion annually over the coming years, the utility said.Iberdrola expects its regulated asset base to triple to more than €90 billion in 2031 from the level in 2020. While it will grow almost fourfold in the UK and near double in the US, assets will shrink to €3.5 billion in its home market of Spain. The company sees “low incentives for investments and operation and maintenance costs” in Spain. The reliability of the Spanish power network has also been questioned in the wake of the nationwide blackout that left millions of people without electricity at the end of April. Spanish market regulator CNMC has proposed increasing network returns to 6.46%, below the level in other European countries. Utilities lobby group Aelec, of which Iberdrola is a member, has said the low returns could jeopardize investments in the country. This story was originally featured on Fortune.com