GDANSK, Poland, Dec 18 (Reuters) - Iberdrola said on Friday it had bought a 50% stake in North and Baltic Sea wind farm company Sea Wind for an undisclosed sum to jointly develop a portfolio of offshore projects in Poland, a new market for the Spanish group. The two companies plan to build a pipeline of seven projects in Poland’s largely untapped Baltic Sea market with the potential to deliver up to 7.3 gigawatts (GW), Iberdrola said. Facing pressure from the European Union to reduce carbon emissions, Poland, which generates almost 80% of its electricity from coal, signed a letter of intent in July with lobby groups and industry representatives to collaborate on offshore wind farms in the Baltic Sea. The Polish government wants the country’s first wind farm to enter production in 2025 and to build up total offshore wind capacity of 10 GW by 2040. Interest in the country’s wind power potential has been heating up. Denmark’s Orsted and state-run PGE are pushing to sign a development deal by the end of the year. Iberdrola said the deal was in line with its strategy to diversify into markets with favourable investment conditions. “The move also allows the company to position itself in the initial stage of development of the country’s offshore wind market, with great growth potential in the coming decades,” the company said in a statement. It follows a preliminary agreement signed this year between Iberdrola and Poland’s Enea to assess the potential to install about 3.3 GW of offshore wind capacity in the Baltic. Iberdrola announced a 75 billion euro ($91.91 billion) plan last month to invest in renewable energy production, grids and retail operations by 2025.