Renewable energy sources are experiencing impressive growth due to the economy’s decarbonization targets. In order to reach the goals set by the EU, it is very important to foster the application of different solutions to maximize green energy production. Micro hydro potential from water networks stands out as an untapped source of green energy, mostly wasted during the operation of water networks. But how competitive is micro hydropower when compared to other RES? A simple comparison of the levelized cost of energy (LCOE) between a 100kW PV array and different sizes of micro hydropower is presented below:
The annual energy yield of a 33 kW Easy Hydro turbine operating for 4,500 hours per year would be similar to the annual energy yield of a 100 kW PV array. The operational time of the water turbine could be even greater in most circumstances, surpassing the annual energy yield of the 100 kW PV array with just a third of its nominal capacity.
The LCOE obtained for these two systems was: 0.042 €/kWh for the water turbine and 0.05 €/kWh for PV.
When comparing the same nominal power output (100 kW – 4,500 hours of operation) this difference increases, decreasing the LCOE of the 100 kW hydro turbine down to 0.033 €/kWh.
This shows how micro hydropower, despite presenting a slightly greater capital expenditure, presents a greater value from the investment point of view with a more competitive LCOE.
Common single-stage, centrifugal Pumps as Turbines are a very versatile family of devices suitable for a large variety of flow rate and head conditions. However, these machines can have poor efficiency when used at sites with low flow and high head where traditionally a Pelton turbine would be the preferred choice.
Instead, for those locations Easy Hydro can design and supply a multistage Pump as Turbine which consists of a number of impellers arranged in series. By distributing the head drop across multiple impellers, the turbine can therefore run in a flexible and efficient way at just a fraction of the price tag of a custom-made Pelton wheel.
How Easy Hydro turbines recover energy from on/off or ballcock inflow valves
Most large industrial water consumers are required to connect to the mains through a break tank in order to avoid backflows into the water distribution network. The inflow into such tanks is commonly regulated by a pilot or ball-operated inflow valve according to the level in the break tank itself. However, this approach is energy wasteful and highly inefficient since a stream of pressurized water is being brought to atmospheric pressure in the open-air tank before being distributed to the various industrial processes either by gravity or by further pumping.
An alternative method consists of using small-scale and modular hydropower turbines which can be placed in a bypass of a tank inflow valve and thus transform the dissipated pressure into usable electricity that can be consumed locally or exported to the grid. The type of turbine proposed is reliable and widely tested and consists of standard pumps running in reverse as turbines which only cost a fraction of a conventional custom-made hydro turbine.
Easy Hydro was one of the 12 startups selected for the Phase 1 of the 2021 EIT RawMaterials Accelerator programme, with a focus on further refining our business model and exploring the opportunities given by the market.
Our team will work under the guidance and coaching of the EIT RawMaterials Consortium over the next three months, with the target of stepping up to Phase 2 later in the year.
Easy Hydro collaborates in a research to estimate the micro-hydropower potential in water networks across part of the EU
The Easy Hydro team has participated in a research focused on the quantification of the available energy recovery in water networks including drinking water, wastewater and irrigation across several EU countries as part of the REDAWN project. A total energy recovery potential ranging between 480 – 822 GWh was estimated, which would decrease the energy consumption of the water networks between 1.7 and 13%. This would significantly reduce the CO2 emissions associated with the water industry, whilst actively contributing to net energy efficiency gains.
Very interesting results, which will foster the adoption of micro hydropower solutions to counteract the effects of climate change and advance the EU targets regarding decarbonizing the economy.
Easy Hydro, a spinout from Trinity College Dublin, has been awarded a €49,000 Booster grant from the EU consortium EIT RawMaterials to build a pilot energy recovery installation at Tara Mines in Navan. As a part of a collaboration between Easy Hydro and the site owner Boliden, a novel type of water turbine will be commissioned to recover energy from the underground water mains carrying fresh water down the mine.
The site
It has been decided to place the Easy Hydro turbine in parallel to an existing pressure reducing station on a DN150 pipeline carrying clean water from the surface.
With an average flow rate of 22 l/s and a pressure drop of 21 bar, the turbine will output up to 30 kW of clean renewable energy resulting in yearly savings of over 200 MWh of electricity otherwise imported from the grid. Such amount of energy corresponds to the annual consumption of nearly 50 average Irish households.
The proposed installation will directly offset over 60 tons of CO2 per year, and such technology if replicated over a number of other similar locations within the same mine has the potential to significantly reduce the current carbon footprint of Tara Mines.
Besides, the expected payback time of the installation is between 2 and 3 years and considering an equipment life of 25 years the generated energy will feature an extremely low Levelized Cost Of Electricity (LCOE).
This work is highly relevant to our wider sustainability agenda and compatible with the underground mining operations carried out by Boliden Tara Mines
Paschal Walsh, Boliden’s Environmental, Health, Safety & Energy Manager
This project in collaboration with Boliden and EIT RawMaterials is an excellent opportunity to demonstrate the applicability of the unique Easy Hydro energy recovery technology in the mining sector
Daniele Novara, Easy Hydro’s Managing Director
Description of the technology
Small-scale and modular hydropower turbines which can be installed along existing pipe networks. Such turbines can be placed in a bypass of an existing valve, e.g. pressure reducing valves, control valves, tank inflow regulation valves. The turbine can thus transform the dissipated pressure into usable electricity, with power outputs ranging from a few kilowatts up to hundreds of kilowatts.
The type of turbine adopted is reliable and widely tested and consists of standard pumps running in reverse as turbines (PAT – Pumps As Turbines) which only cost a fraction of a conventional custom-made hydro turbine.
Features:
The turbines consist of standard water pumps running in reverse mode
Range of power output from 1 to 300+ kW, range of flows from 15 to 3,600+ m3/h, range of pressure from 1 to 300 bar
Benefits:
Low installation cost, just a fraction of a conventional turbine (Francis, Pelton, Crossflow…)
Easy maintenance, as pump spare parts and skilled technicians are easily available
Modular system, plug and play
Fail-safe bypass and hands-off operations
Values:
Exploiting an untapped potential within an existing pipe infrastructure
Reducing the electricity needs and CO2 emissions of a mine
The modernization of hydraulic infrastructure in irrigation, from traditional channels and ditches to pressurized networks, has led to significant improvement of the water efficiency (conveyance and consumption). Nevertheless, this fact brought a dramatic increase of the energy consumption, causing impacts on farming margins and operational costs.
On-demand irrigation networks have the main advantage of offering continuous water availability, giving a great flexibility to farmers for irrigating. However, the occurrence of areas with excess pressure, which must be dissipated in some way, has become more frequent. Micro-hydropower turbines for energy recovery arise as an attractive solution to counteract the negative impacts due to the high energy cost of the process. Given the seasonality of the activity, cost-effective solutions are in dire need and hydropower stands out as a technology capable of bringing electricity to remote places with no grid connection where an excessive water pressure to be dissipated within an irrigation pipe.
The rights to use the pump-as-turbine selection software has been granted to the Venture by Trinity College Dublin.
The selection software enables an accurate selection of the most suitable hydraulic pump (end-suction, inline, multistage, split-case) to work as a turbine for any given site. Until now, the available alternatives were either experimentally testing many different pumps in reverse or performing a numerical CFD simulation to predict their performances – both extremely time and resource consuming methods.
Screenshot of exemplary results from the software.
The 3 kW peak pico pump-as-turbine designed by the Easy Hydro team has been operating for the last 12 months. The turbine is located at the inlet of a gravity-fed raw water supply line, and contributes to reducing the energy demand of the adjacent treatment works by nearly 20%.
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