This project (‘Hydro-BPT’) investigates the technical and economic feasibility of energy recovery from the water industry through the installation of micro-hydro turbines in Ireland & Wales. Realisation of this energy recovery potential would:
(i) Reduce energy costs,
(ii) Reduce the use of carbon intensive fossil fuels,
(iii) Establish Ireland & Wales as leaders in the field of water and wastewater services.
UK & Irish Water Industry Facts:
2. Hydro-BPT Project
Installation of micro-hydro turbines at strategic locations within the water and wastewater networks would exploit otherwise wasted energy; displacing some of the energy currently bought in by the industry, with excess energy fed back into the electricity grid. This will enable the water industry to reduce its operating costs of supplying treated water and reduce its CO2 emissions. The primary objectives of the Hydro-BPT project are to:
Investigate the technical feasibility of micro-hydro: continuing this preliminary investigation to produce detailed design and implementation guidelines.
Assess the Environmental Impact of this new technology: CO2 emissions, life cycle analysis.
Develop a GIS database of micro-hydro schemes and their energy recovery potential for the Ireland-Wales region. Develop a business/collaboration model for the implementation of micro-hydro by industry stakeholders in practice.
Fig. 1. Primary Areas of Research and Key Stakeholders Involved in this Research.
3. Identifying Potential Energy Recovery Sites
The project will exploit the potential for energy recovery that exists at different locations within the system. Such potential locations are listed below and displayed in Fig. 2.
Water Supply & Treatment Systems Waste Water Treatment/Collection Systems
- Service Reservoirs - Energy recovery in flood/Storm-water flows
- Pressure Reducing Valves - Energy recovery at sewer outfalls
- Off-peak energy recovery
- Water Treatment plants, head of works (inlet)
Fig. 2. Locations for Energy Recovery in the Water and Wastewater Supply & Treatment Systems.
4. Quantifying the Hydropower Energy Potential
Data was collected from water suppliers within in Ireland & Wales on the location of all current (Fig. 3) and potential sites and the head and flow characteristics were used to calculate the available energy potential.
Fig. 3. GIS Mapping for Some of the Existing Hydropower Sites Identified in Ireland & Wales.
5. Micro-hydro Generation
Globally, hydropower currently contributes to the majority of renewable energy production; however, it is only recently that the recovery of excess energy within water distribution networks and wastewater treatment facilities has been recognised as a potential source of electricity generation. Micro-hydro turbines have a typical capacity to generate up to 100 kW of power. The project will explore the complexities associated with turbine installation (e.g. site-specificity) and the challenges of their design and implementation. Such challenges can include:
Flow variation (diurnal, weekly, seasonal)
Power quality & energy storage
Turbine selection & operating conditions
Downstream impact (changed flow patterns)
Effect of tides (outflow head)
6. Environmental & Economic Impacts
The installation of micro-hydro turbines has a much lower environmental impact than larger hydro installations. To assess the environmental impacts of micro-hydro technology, a rigorous life cycle assessment approach will be adopted that will consider: (i) the manufacture, installation and maintenance of the turbines, and; (ii) the displacement of grid electricity and associated greenhouse gas emissions.
Significant challenges include taking into account temporal variability in pressure and flow characteristics, site-specific efficiencies for different turbine types, and the different renewable energy incentives between the two countries that will determine the economic feasibility of specific installations. The calculation of net life cycle financial and carbon savings depends on the following:
i. Accurate identification of energy recovery opportunities (potential sites) across the sector.
ii. Matching appropriate, economically viable turbine types to each potential site.
iii. Quantification of applicable financial incentives for micro-hydro, e.g. feed-in-tariffs.
Fig. 4. Categories assessed as part of Life Cycle Assessment (LCA) for Micro-hydropower installations in Ireland & Wales.
7. Project Collaboration & Business Model
The project involves collaboration with a range of separate organisations; including local authorities, electricity suppliers, energy regulators, turbine manufacturers. Key elements of the business role include determining the best mode of collaboration between each of these bodies and development of an effective implementation plan for roll-out of the technology. This is key to ensure that capital investment for micro-hydro schemes are returned within an acceptable period and also that monitory savings are maximised.
Fig. 5. Hydro-BPT Collaboration Model Between Various Industrial Partners.
This project will provide a better understanding of the potential for energy recovery from micro-hydro installations in the water industry. This will ultimately help improve the economic and environmental sustainability of the water industry.