Run of River Generator

About

When we refer to Green and Renewable Energy, hydroelectric power generation does not normally appear at the top of the list, yet here in the UK we have an extensive river system that flows past us, untapped, every day. What if we could utilise this untapped, clean resource with a modular, self-contained electric generating system? Although many people have heard of hydroelectric power, a recent survey found that there was little understanding of how it worked. Some respondents saw hydroelectric schemes as potential tourist attractions, in keeping with the historic water mill, whilst others were concerned that valleys would need to be flooded. In 2015 hydroelectric power generation accounted for 16.6% of the world’s electricity, which was 70% of all renewable electricity. This is expected to increase by approximately 1.3% annually for the next 25 years. As of 2018 the UK’s hydroelectric power generation accounted for 2.2% (1.87 GW) of the UK’s total generating capacity. This equates to 4.2% of the UK’s renewable energy generating capacity, a significantly lower percentage. This figure includes the established large scale conventional hydroelectric power stations and Low Head “Run of River” (RoR) hydroelectric schemes. Run of River schemes differ from conventional hydroelectric power generating installations in many ways. The term Low Head refers to the height difference between the water intake and discharge levels which is typically less than 20 metres, significantly less than conventional hydroelectric power installations. Most RoR installations require little, or no, water storage to power the turbines. This means that the civil engineering and environmental disturbance is substantially less for a RoR installation than a conventional hydroelectric power station. Whilst there are several established “large-scale” Hydro Turbine designs in use, these types of generators come with some noteworthy problems, they: • Require significant installation construction which impacts on the environment • Are vulnerable to debris in the water flow, • Dangerous to aquatic wildlife • Are not suitable to Low Head, Run of River, applications. Most of the alternative, small scale submersible generators currently available appear to be “wind turbine like”. These devices are adequate for small, personal electricity generation but pose a different set of problems when trying to “up-scale” for larger output electricity generation. This project sets out to refine the fundamental design principals required to develop a modular self-contained, Low Head, Run of River Hydro-Electric Generating Device (HTG, Hydro-kinetic Turbine Generator). The HTG project is exploring and refining solutions to the following design problems: 1. How can we maximise water flow through the device? 2. How can we maximise power extraction from water flow? 3. How can we maximise electricity generation? The design beats all these problems by using: • Large diameter, thin section rotor bearing arrangements and modular support structure • Internal (& external) Rotor Geometry analysis & Stator Tube Geometry Design • Magnet array arrangements and magnetic flux geometry analysis • Armature winding arrangements and active output control system. DETAIL DESIGN CONSIDERATIONS: The core of this design, put simply, is a long rotor within a tube. The rotor development will focus on extracting the maximum amount of energy from a continuous flowing body of water, experimenting with length v diameter ratios, rotor vane arrangements & pitch (variable), rotor surface textures, etc. The project sets out a design evolution sequence for both the rotor and tube, drawing on recent technical advancements such as the ducted turbines that are being developed in the wind turbine sector. The bearing & support arrangement will be a significant challenge, to maximise the flow through the Generator the bearings are located around the periphery of the Generator rotor. We will experiment with proprietary large diameter, thin section bearings as well as designing our own arrangements. Once an efficient internal rotor and tube design has evolved, the next step will be to incorporate rare earth magnet arrays into the structure of the internal (and external) rotor(s) together surrounding armature arrays into the tube. There are proprietary magnet and coil assemblies that could be incorporated into the prototypes to help prove the concept. Our Prototypes and Production units will utilise additive manufacturing technology. We plan to incorporate industrial plastics and new composite materials throughout the development and manufacture of this generator and make use of new control technologies when developing the generator during future technical design phases. As well as establishing the core design principals, we must consider the issues with up scaling this design and the need to minimise the civil engineering required during installation and therefore minimise the impact on the environment. The Ecological and Environmental issues, that this project will inevitably raise, will be constantly questioned and address throughout the development cycle of this project. TARGET MARKETS The business opportunity that this project will address can be split into three areas: • Personal o Small-scale [Pico] electric generation. A Personal Generator will need to be portable and easily sited into a flowing water course. It must also be safe and simple to control. • Community o Mid-scale [Small-Mini-Micro] electric generation This type of installation could either be an up-scaled version of a single generator or a “Turbine Gang” of interconnected smaller units depending on the manufacturing process and materials that have evolved during the earlier stages of development. A simple installation, commissioning and maintenance approach will be central to our development process. • Commercial o Large-scale [Macro] electric generation Exploiting this type of generating installation will be challenging because of the civil engineering involved and the established “industry standard” turbine designs already in use, but we are confident cost-effective arrangements will evolve during the later stages of this project’s development that could challenge the current thinking of the industry.