Worldwide, floating solar parks are on the rise. Not only on inland waters, such as lakes and reservoirs, but the first offshore floating solar parks are also now getting off the ground. In this blog, we discuss the opportunities and challenges of solar parks on inland and offshore waters. We also discuss in concrete terms which (offshore) projects are being realised and how we apply our knowledge on the opportunities and challenges of floating solar parks in Indonesia.

To identify the opportunities and challenges, it is important to distinguish between 2 types of locations: locations on inland waterways (such as lakes, abandoned sand mines or dredging depots) and locations at sea. 

The challenges of offshore floating solar 

It is often assumed that there is sufficient space within existing offshore wind farms for floating solar farms. However, complex issues arise if the wind farm is already operated. After all, this means that the wind farm operator has to share its grid connection with the solar farm operator while the wind farm business case does not take this into account. In the situation where wind and solar energy are generated simultaneously, it is unclear which technology has to be switched off and therefore which operator will suffer. 

Solar power generation was also not taken into account in the licensing of existing wind farms. The environmental impact assessments and nature studies prepared at the time did not consider the possible positive or negative impacts of floating solar parks. This therefore makes developing floating solar parks in existing offshore wind farms very difficult. The development of current offshore wind farms can, however, take into account the integration of solar energy into the system. This was a crucial aspect in the tender for lot IJmuiden Ver Beta, which was recently won by Vattenfall. 

It is important to note that the potential positive or negative impacts of floating solar parks are relatively limited, on both inland and offshore sites. There are several projects where monitoring of ecology is taking place to develop models that can map the effects. 

The opportunities of offshore floating solar 

It is important to note that the potential negative ecological effects of floating solar parks on both inland waters and offshore locations are relatively limited. There are various projects where ecological monitoring takes place to develop models that map the effects. No significant negative effects have been observed here yet. 

In addition, offshore floating solar has several other advantages. For example, the landscape impact of an offshore solar park is negligible compared to solar parks on land. Furthermore, the impact on flora and fauna on land is limited. Solar energy at sea can also help to reduce the load on the electricity grid on land, especially in densely populated areas where the demand for electricity is high and space is scarce. 

The challenge of floating solar on inland waterways  

Abandoned sand pits, dredging depots and lakes are generally considered inland water locations where the wave height is relatively low, around 2 metres. However, the question is how many such locations are still available in the Netherlands, apart from the IJsselmeer. The Netherlands leads Europe in terms of installed capacity of floating solar parks. To illustrate: In 2023, the Netherlands had almost 300 MW of installed capacity of solar power on water. 

Interestingly, different types of systems are being designed and installed for inland waterways on different continents. In Southeast Asia, the emphasis is on low installation costs, sometimes paying less attention to maintenance costs. It is therefore not unexpected that some systems in Southeast Asia are damaged beyond repair after a storm. In conclusion, there is a need to strike the right balance between one-off investment costs (CAPEX) and maintenance costs (OPEX) to keep a system operational for 25 years. 

The environment therefore plays a major role in the opportunities of floating solar parks. As water and electricity are not compatible, a carefully designed cable management plan is essential to ensure that the system operates reliably and safely. In addition, waves cause fluctuations which make damage more likely to occur. It is therefore essential to carefully consider the impact of wind on anchors during the engineering phase, and then design a system that will stay in place for about 25 years. 

Floating solar in the Netherlands 

For solar energy on inland waterways, there are several locations that are being offered to the market by the Rijksvastgoedbedrijf through tenders. The tender for the Slufter dredging depot is currently running and five parties are preparing a bid for this. A great project where the main focus is on how to realise added value and good neighbourliness while allowing the dredging depot to remain in use unhindered. In addition, the Kreekraksluizen locks are also being offered by the State Property Company. If the project goes ahead, the State Property Company is expected to start the public tender procedure in late 2024/early 2025. 

The development of the solar atolls along the Wieringermeer dyke, is a great example of a project where energy transition goes hand in hand with nature. In this project, nature is enhanced, and recreational facilities are developed at the same time. The consortium of GroenLeven and Van Oord is working on this project. These parties are working together with H+N+S Landscape Architects, who created the illustrations below. 

Sharing knowledge and experience  

Because the Netherlands is making great strides in the development of floating solar parks, it can export the accumulated knowledge abroad. Among others, Pondera is active in Indonesia to develop floating solar panels on water reservoirs in cooperation with other parties. Currently, Pondera has assessed and mapped about 250 water reservoirs to then carry out a feasibility study for two sites. An important part of this is the preparation of an environmental impact assessment and weighing up the possible positive and negative impacts. Below, the most crucial impacts have been contrasted. 

Table 1: Benefits and challenges of FSPV systems in Indonesia