Hybrid power plants – the energy solution of the future?

In addition to developing technology for hybrid power plants, an important task is to investigate how such power plants can minimise damage to ecosystems, the local population and society in general.

In the HYDROSUN project, partners from industry and research are working together to develop expertise and knowledge to build and operate hybrid power plants that combine hydropower production with floating solar power plants. Dialogue with the local population is an important part of the project.

One of the first in the world

In short, hybrid power plants involve combining two or more forms of renewable energy production, as well as energy storage and digital control systems for stable and predictable delivery to the grid.

A key case study in the HYDROSUN project is the Magat Dam in the Philippines which includes a large hydroelectric power plant established in the 1980s, a small floating solar power plant and a battery park.  Several of the industrial partners in the project have a role in the Magat case, both on the owner and the technology supplier side.

"Since all the components of a hybrid power plant are in operation in Magat, this is a very exciting case both for the expertise project and the business project," says Chief Scientist Erik Stensrud Marstein at the Institute for Energy Technology (IFE).  "This power plant produces solar, hydro and battery power."

"We have high expectations for the potential of combining floating solar panels with water reservoirs for increased security of supply and more affordable power production, while at the same time taking environmental and social considerations into account. We need to consider the impact of this energy production method on the local ecosystem and society. Until we can test and verify it, we cannot be sure that we will succeed," says NIVA researcher François Clayer.

Challenges and opportunities

Energy generation is dependent on access to production areas, and sustainability requirements are becoming increasingly important. One of the most important challenges with renewable energy is the storage of weather-dependent power. Without storage facilities, there will be an imbalance between supply and demand.

NIVA's role

NIVA's task in the HYDROSUN project is to calculate and assess how floating solar power plants on hydropower reservoirs and lakes affect ecosystems and local communities. We will contribute with a proposed roadmap for assessing the impacts of floating solar power. In 2019, the World Bank published a handbook for floating solar called "Floating solar handbook for practitioners". However, as this is a new technology, relatively few countries have had time to develop a framework for licence assessment.

"To study the positive and negative effects of the hybrid power plant, we use a combination of observations and modelling," says Clayer.

There are high expectations for the positive effects of floating solar on reduced evaporation and eutrophication. But so far, there are few studies and analyses based on primary data.

When it comes to the impact these hybrid power plants can have on local communities, it is important to consider both direct effects, such as competition for space, and indirect effects on reservoirs or lakes. We know that when a floating solar power plant covers the water surface, it can lead to reduced evaporation and thus to more available water. On the other hand, the cover can also reduce the oxygen content in the water masses.

"Another important task for NIVA in this project is to identify measures that can promote the added value of hybrid solar power plants as well as measures that can minimise any negative consequences. The goal is to reduce negative impacts and increase the benefits of power production for the environment and the local population," says Senior Researcher at NIVA, Ingrid Nesheim.

Conflicts of interest

Lakes and hydropower reservoirs worldwide are important areas for transport, fishing, recreation and cultural heritage. In sub-tropical and tropical regions, such areas are particularly important for livelihoods and food security, and there are many user interests, including in industry and small-scale enterprises.

A necessary starting point for development projects like HYDROSUN is to undertake a broad stakeholder mapping to understand user interests and how they vary throughout the year, for example in relation to agricultural production.

"It is important to talk to the residents in villages around the reservoir, to sector and environmental authorities and to industry players. In this way, we find what we need to know in order to make decisions that benefit both the local population and society," says Nesheim.

Possible to scale up

Lessons learnt from the HYDROSUN project are unlikely to be applicable to Norwegian conditions. Nature, climate and temperature conditions are too different. But for large water reservoirs in South America, Africa and Asia, HYDROSUN results may pave the way for similar projects. Before that can happen, the interdisciplinary research team must check that key system components can be trusted. They also need to develop new methods and control measures for efficient design, planning, operation and maintenance of hybrid power plants. In addition, they must investigate how well the hybrid power plants work in an uncertain market and an ever-changing climate.

"We have designed the project to be as generic as possible. The potential for floating solar panels is greatest in the tropical regions, with contrast between loads of water during the rainy season and lots of sunshine during the dry season. The goal is to scale up renewable energy as quickly, cost-effectively and sustainably as possible," Clayer concludes.