INNOZOWA, INNOvative solar PV on WATER

Fortunately, sustainable energy has become an indispensable part of our world. The demand for clean energy continues to increase, and the development of ways to harness clean energy sources is accelerating. For example, there are major national and international ambitions for the realization of solar energy. Space is needed to realize solar parks. Water potentially offers space for floating solar parks.
In anticipation of this development, the Rivierenland Water Board has started the INNOZOWA innovation project.
INNOZOWA focuses on the development of floating solar PV for shallow waters such as water storage facilities. As a water board, we see it as our social duty to investigate whether and how sun on shallow waters can be matched with our statutory targets (clean and sufficient water). Using shallow waters for floating solar PV offers opportunities, but also poses several challenges. An initial exploration of these opportunities and challenges was carried out in the period 2019-2021. Following this exploration, we will start a new phase in 2022. We focus on researching the ecological effect and reducing (construction) costs of floating solar PV. For this we realize test setups, in which we apply various innovative solutions and investigate their effectiveness. In doing so, we mainly look for solutions that lead to cost reduction as well as prevent negative effects on ecology/water management. The test set-ups are therefore intended for experimentation; this way we learn faster and more by just doing it.

How do we do that?

The answer to that question is threefold:


to be able to launch a sound system…

Our research focuses on both ecological and technical research.
Ecological research is in line with the findings from the first phase 2019-2020. In order to gain more insight and to clarify these first results, we are realizing a large-scale test set-up (40 m). We vary the degree of coverage with PV panels. We do this to gain insight into the effect that cover has on light climate and associated ecological processes. By varying the cover ratio (50-100%) we want to visualize the maximum allowable cover before this has a negative effect on ecology.
Technical research focuses mainly on the effectiveness of new innovative solutions and applications that we integrate in the test set-up. This may concern the effectiveness with regard to cost reduction or the prevention of ecological effect.


INNOZOWA is unique because we are working to develop a sun on water system suitable for shallow waters. Because other interests play a role in shallow waters, the development of this system is different from existing systems that are often used in deep waters.
We are committed to new innovative technical developments that both contribute to cost reduction and prevent a negative impact on ecology. In addition, we naturally adhere to the basic principles that sun on water must be profitable (compared to land) and that sun on water must not hinder the performance of our water board tasks. We are also looking at the use of biobased material and, of course, at the possibilities of further scale-up.

To learn by practise

Three new pilot set-ups followed from both research and development.

pilot 1.

This test set-up is primarily aimed at conducting ecological research into the effects of the sun on water. In order to be able to study the effect of the sun on water, we are realizing a large-scale test set-up (approximately 40 meters in diameter). Because virtually no knowledge is known about the effects (which and when they occur) as a result of sun on water, we use the test set-up to explore these limits. The test set-up therefore has a variable coverage. We start with a coverage of about 50%. Depending on the results, we increase the coverage to 75% or higher. In this way we want to gain insight into what effect which cover has on aquatic ecology. In addition, we also look at whether covering waters has an effect on the emission of greenhouse gases from waters.
With the test set-up, we are also investigating how effects on ecology can be mitigated or prevented. To do this, we mainly look for smart solutions that make a positive contribution to both the ecology and the economy.


– Sun tracking. It follows from the first pilot that a sun-following sun on a water system can significantly increase the energy yield. This helps to arrive at a positive business case. Because the set-up only has a 50% coverage, it was decided to arrange the open parts in the system as so-called skylights. As a result of the rotational movement of the field, these skylights prevent continuous shadowing under the field. As a result, negative effects on ecology as a result of reduced light incidence can be mitigated.


– Field movement. Being able to move a floating system follows from the first pilot in which the system had to be moved so that regular management and maintenance of the water board would not be hindered by this. We are going big with the test set-up. The entire test set-up can be moved over the water to a completely new location. As a result, the arrangement does not hinder the regular maintenance of the water board, but it also offers the possibility with which aquatic ecology can recover. This follows the principle of so-called rotational cultivation, whereby we can adjust the frequency of the movement depending on the effects and the speed at which they occur. This solution is also aimed at preventing a continuous pressure on marine life as a result of covering an open water system.


– Drive. In order to be able to run and move the test set-up, we opted for a drive with (electric) motors. We expect this to have a positive effect on ecology as it mixes water below the field with water that is not covered by the floating setup. The (active) mixing of water can mitigate the loss of wind and wave action by covering waters and therefore has a positive effect on ecology


– Look through. Potentially, this test set-up can be seen as a first possibility of a completely autonomous floating sun on water system. A system that (continuously) autonomously follows the sun and moves over an available area of a water surface, so that no negative effects on ecology occur.

pilot 2

This test set-up is aimed at reducing costs. It follows from the first pilot that the sun on water systems is sensitive to wind action. Although the number of storms in the Netherlands is relatively limited, systems on the water must meet wind load standards. This means that sun on water systems are often heavy and/or over-dimensioned. The most obvious cost reduction therefore lies in saving on construction costs.
The test set-up developed for this purpose is unique. It is the world’s first sun on water system that avoids wind load by temporarily sinking underwater. Above wind force 6, the entire system automatically sinks under water. As a result, wind load and thus construction costs and damage to the system are literally avoided. As soon as the weather conditions are favorable again, the system will automatically surface. This test setup is so revolutionary that research and development is primarily focused on proof of principle. After that, this test set-up will be further developed for efficiency.
see through. The test setup is so revolutionary that we are realizing a separate test setup for it. However, we expect that if successful we will be able to translate this technique relatively easily into large-scale application as in pilot 1. In connection with the height of the construction itself and the available water depth, sinking an arrangement in deep water is relatively simpler than in shallow water.

pilot 3

In this test set-up we are investigating the possibilities of applying biobased material. We have chosen to use bamboo composite. In this pilot, we are using bamboo composite for the first time for parts of a floating structure. The possibility of using these types of materials is closely related to the development towards a lightweight construction that is possible when wind loads can be avoided. This pilot is therefore closely related to pilot 2. With this test set-up we mainly look at how resistant the material is in the transition environment between air and water.