Renewable energy sources such as solar panels or geothermal energy are good for the climate, but what impact do they have on plants and animals?

Research organisations Deltares, TNO, Wageningen University & Research and KWR are investigating this as part of the ‘Ecological Knowledge for the Energy Transition’ (KEEN) programme.

1) Are solar panels bad for the environment?

That depends on where they are installed. Floating solar panels block sunlight, which hinders photosynthesis, impedes the growth of aquatic plants and algae, and reduces oxygen levels. It is therefore important not to cover too much of the water’s surface with panels. On land, panels affect the distribution of rainwater in the soil. This need not be a problem, provided it is taken into account during installation.

2) What about aquathermal energy?

Aquathermal energy comes in various forms. In TEO (Thermal Energy from Surface Water), heat and cold are extracted from rivers, lakes or canals, and then used to heat or cool buildings. This naturally affects the temperature of the water. In small, stagnant bodies of water, this can cause significant ecological impacts, disrupting the natural water system. The filtration of the water (to prevent the heat exchanger from breaking down) also contributes to this, albeit to a lesser extent. The damage can be mitigated by taking these effects into account during the design phase, and by monitoring the temperature and, where necessary, minimising the use of TEO.

3) What impact does underground energy storage have on groundwater?

In underground energy storage, the subsoil is used as a sort of thermos flask, which prevents warm water from cooling down too much and cold water from heating up too much. The water is drawn up to cool or heat buildings, and then pumped back down again. The impact of these temperature fluctuations on groundwater quality is negligible, but the back-and-forth pumping does cause mixing of the groundwater. This is not always desirable, particularly if the water is used for drinking. Here too, the guiding principle is: take this into account during the design phase, and keep a close eye on the effects.

4) Has any research been carried out into offshore wind farms?

No. The KEEN programme is designed to fill gaps in our knowledge, and a great deal of research has already been carried out into offshore wind farms. For example, it is known that birds are affected by them and may fly into them. Wind turbines also produce underwater noise that disturbs animals. Solutions already exist to (partly) mitigate these problems, such as black turbine blades, the early detection of birds combined with the shutdown of turbines when they fly overhead, and bubble screens to act as noise barriers. It is also known that the foundations of wind turbines can sometimes have a beneficial effect, as they act as artificial reefs.

5) What is the added value of all these research findings?

If it is clear that a particular method of energy generation is harmful to the natural environment, a decision can be made to intervene – either by not proceeding with it at all, carrying it out on a smaller scale, or devising a more sustainable design. Where the results are favourable, the research can actually accelerate the energy transition. Licensing authorities such as Rijkswaterstaat, provincial authorities and water boards often have to make decisions whilst there is uncertainty about the potential effects of those decisions. As the precautionary principle applies in such cases – requiring potential adverse effects on nature to be taken into account – this regularly leads to delays or the rejection of planning permission applications. This slows down the scaling up of renewable energy.

Opening image: Deltares