Social Acceptance and Mitigation of Environmental Impact

About

Increased operating flexibility of hydropower plants will cause adverse effects on downstream water courses unless mitigation measures are taken. Work Package 5 focuses on the mitigation of environmental impact through (1) developing a new concept named Air Cushion Underground Reservoir (ACUR), (2) flow scenario modelling in order to derive the impact of 30 starts and stops per day on water levels, temperatures and velocities in the river (with and without ACUR), and (3) evaluate the efficiency of the mitigation technology on fish population. Further, work package 5 addresses the social acceptance of flexible hydropower.

Objectives

Work package 5 aims to assess social acceptance and test innovative methods to mitigate environmental impacts of flexible hydropower.

• Develop technology for active storage of water that will enable high ramping rates and minimize the negative effects from the discharge into the downstream river
• Utilise existing data and model setups for the given cases to investigate the influence on river ecosystems subjected to 30 start-stops per day with and without mitigation
• Investigate socioeconomic and environmental aspects of use groups/stakeholders from high ramping rates, through a survey of public resistance and acceptance to 30 start-stops per day

Tasks

5.1. Technology for mitigation of highly fluctuating discharges into downstream river

A 1D model will be established for the power plants under investigation, with the possibility of switching on and off the presence of ACUR (Air Cushion Underground Reservoir). A prescribed operation plan is then simulated (as an example 30 starts and stops), and iterations on what technologies are necessary and how to govern the ACUR for the desired mitigation of discharge fluctuations will be performed.

5.2. Flow scenario modelling

The temperature, water levels and flow will be modelled with HEC-RAS and with Computational Fluid Dynamics (CFD) for two cases. This will first be done for current running schemes of the turbines so that the models can be validated. Next, simulated flow that mimics typical turbine operations from WP2 will be used as input for the simulations and measured climate and other forcing data will be used to drive the models.

5.3. Evaluating the efficiency of the mitigation technology on fish populations

To evaluate whether the mitigation technology described in Task 5.1 will have the desired effect on downstream aquatic ecosystems, the simulated effects on temperature and velocity fluctuations from task 5.2 will be implemented into a fish population model.

5.4. Assessing the social acceptance of increased ramping rates

Social acceptance will be assessed by in-depth interview of different stakeholders. Based on the outcome of the social acceptance study, we will formulate guidelines to power producers and policy makers for public and stakeholder participation and involvement related to how to increase social acceptance of highly flexible operation of hydropower plants.

Participants

Work package 5 is led by the Fluid and Experimental Mechanics Division at the Department of Engineering Sciences and Mathematics, LTU.

Contact: Prof. Staffan Lundström

Partners:

• NTNU (Leading Task 5.1)
• LTU (Leading Task 5.2)
• Lyse
• VATTENFALL
• Statkraft
• NINA (Leading Task 5.3 and 5.4)
• EDR