Wind at sea can be harnessed and converted into electrical energy through the installation of offshore wind farms. They are called offshore wind farms and, as the name suggests, they are wind farms located offshore. While they are most commonly installed in seas or oceans, offshore wind farms also include those that can be built on the continent, such as in large lakes. The first offshore wind farm was installed back in 1991 in Denmark, and since then, the number of such projects has seen significant growth. Offshore wind farms have become a crucial player in the global renewable energy market.
Europe has placed the development of offshore wind farms at the center of its energy transition, and governments across Europe have committed to developing 150 GW of offshore wind power by 2030. It is projected that by 2050, there will be as much as 450 GW of installed offshore wind capacity in the seas throughout Europe.
Why are offshore wind farms at the forefront of the European energy transition? Firstly, the turbines used are much larger and more powerful than onshore wind turbines, thus generating a significantly larger amount of electricity. There are offshore wind turbines as tall as the Eiffel Tower, with blades as long as a football field, reaching up to 120 meters in length. There are offshore wind parks that supply entire cities with the electricity they produce. The image below shows the Greater Gabbard offshore wind farm in the North Sea, located 23 km off the coast of Suffolk in England. It has a capacity of 504 MW and an annual production of 1.75 TWh.
It is precisely the size of the blades of offshore wind turbines that makes them more productive and efficient. Additionally, wind at sea is more consistent than onshore wind. As a result, offshore wind farms produce a larger quantity of electricity, both in terms of production and consistency. Since winds travel undisturbed over the sea during the day, offshore wind farms ensure constant production of electrical energy during the times of highest demand and consumption. Moreover, offshore wind farms have a higher capacity utilization factor and operate for longer durations compared to onshore wind farms.
Offshore wind turbines in shallow seas are anchored to the seabed, but in deeper waters, they can be installed on floating platforms. Several companies are developing innovative floating offshore platforms for wind turbine installations in deep waters. Croatia is among the countries with deeper seas and favorable winds for the development of offshore wind farms. Each newly installed megawatt of renewable energy project brings us closer to energy self-sufficiency goals, and there is a growing demand for Croatia to start developing offshore wind turbines.
Action Plan for Marine Renewable Energy Sources in Croatia
While the Republic of Croatia does not have explicit capacity goals for marine renewable energy sources (RES) in its strategic documents, countries such as France, Greece, Italy, and Spain have set targets for the development of marine RES projects by 2030. In order to harness their potential in Croatian waters, it is important to start developing a legislative framework for marine renewable energy sources as soon as possible. Therefore, the Renewable Energy Sources Association of Croatia (OIEH) has initiated the project to create the Action Plan for Marine Renewables in Croatia. The completed study provides an overview and analysis of the potential for harnessing renewable energy sources at sea in Croatia and proposes an action plan for their development. The study was financed by the European Bank for Reconstruction and Development, and OIEH gathered experts from the Faculty of Mechanical Engineering and Naval Architecture at the University of Zagreb, OIKON – Institute for Applied Ecology, and the Island Movement for the study’s development.
To kickstart the development of renewable energy sources at sea, there are several points that the Government of the Republic of Croatia needs to initiate. The most important step is the development of the State Spatial Plan for the marine area, which is the first step in establishing areas for marine renewable energy sources. It is important to plan for the multi-purpose development of renewable energy sources at sea, such as co-location with hydrogen production, utilizing existing oil and gas infrastructure, food production from mariculture activities, and more.
In order to see the first operational marine renewable energy sources by the beginning of the next decade, it is crucial to establish state bodies that would begin continuous monitoring and data collection at sea, including wind speed and frequency at higher altitudes, hydrographic surveys, and environmental research.
The development of marine renewable energy sources depends on a variety of factors. After analyzing the main sectors affected by the development of marine RES, this study identified over 29,000 km2 of available area for marine renewable energy sources. This includes areas for offshore wind farms (fixed and floating) and floating photovoltaic power plants. Marine RES projects have significantly longer construction timelines compared to onshore projects due to their size and complexity. Therefore, the European Commission has identified the main challenges and proposals for adopting marine RES. The Action Plan for Marine Renewables in Croatia provides the first such analysis for our country.
