Wave Energy Converter for small communities

Despite the vast wave energy resource available in the world's oceans, financial obstacles associated with developing large scale, complex Wave Energy Converters (WECs) have prevented widespread deployment. Costs related to survivability of extreme weather, offshore maintenance and infrastructure to carry the power from device to power distribution grid have proved prohibitive. Criteria for investors to fund development tend to focus on ability of large WECs devices to economically supply electrical power into the grid for use by concentrated populations.
The concept presented in this proposal takes a different approach, aiming to service more dispersed coastal communities (primarily in less developed countries) where infrastructure to supply electrical power, safe drinking water and to support viable agriculture may be lacking. The concept is for a small scale wave energy converter that can easily be manufactured, deployed and maintained by the very communities that it will serve. It is constructed from readily available waste materials that are otherwise difficult to recycle, making the concept attractive in terms of sustainability and carbon footprint. Whilst undoubtedly inefficient in comparison to large scale WECs, efficiency is substituted for practicality, poverty relief and community ownership. Initial estimates suggest a typical output of around 38KWh/day (sufficient to power a Rural Medical Centre incorporating x-ray and other diagnostic devices) or desalinate up to 10,000 litres of water.
The device will pump seawater, supplying fluid power rather than electrical power. It will operate in shallow water, minimising cost of piping the flow to shore. Most simple devices proposed to pump seawater to shore using wave energy suffer two fundamental problems. Firstly, they usually involve sliding-contact seals, which are prone to failure, often due to corrosion and build-up of marine growth. Secondly, the value of the materials used can be significant, making theft a very real risk, and making storm damage costly/difficult to repair. The device proposed is innovative in that it does not require sliding contact seals. Also, the fact that it is constructed using waste materials means it has little resale value and is cheaply repaired or replaced if damaged.
Once onshore, the flow of pressurised seawater can be desalinated for drinking water, used to generate electricity or used for agricultural purposes such as salt-tolerant crop farming (for biofuel) or in saltwater greenhouses (irrigating conventional crops). An advantage of pumped water is that it can provide energy storage (pumping to an elevated tank), thus supplying power only when required. Industrial partner Mott MacDonald will provide expertise in desalination and other end uses for pumped seawater.

The research conducted by Plymouth University (PU) will focus on analysis and development of the WEC itself. They have already developed basic software based prediction tools or Numerical Models (NMs) and have conducted experiments on the proposed waste materials to give initial estimates for device performance. This grant will enable them to:
1) Expand functionality and accuracy of the existing NMs. This will provide much more realistic simulation of the way the WEC will behave in a given environment.
2) Carry out further experiments and engineering design work on the pump itself, to more closely define the form that the final pump will take.
3) Design and manufacture a representative scale model (that will replicate scaled forces and pumping capacity) for use in a wave test tank.
4) Test the scaled device in PU's Ocean Basin wave test tank in a variety of wave types and operating configurations. These tests will generate data that will be used to validate the NMs. Once validated, the NMs will generate reliable performance predictions for the WEC in real, full scale conditions. They will also be used to optimise the size/shape of the WEC.

Lead partner Clean Energy Limited (CEL) stand to benefit directly from this collaboration - in the short term by enhanced prospects for investment to the next stages (higher TRLs leading prototype deployment) and ultimately by licensing the resulting technology. However, it should be noted that CEL is not a financially motivated company, existing instead to address issues of environmental and social need. As such, CEL have an ethos of reinvesting licensing income to further the development of other projects with clear benefit to society and the environment. Collaborative partner Mott MacDonald (MM) also stand to benefit directly from this collaboration, further developing their extensive portfolio of projects aimed at climate change reduction/mitigation and renewable energy development.

Impact beyond the project partners falls into two categories - impact as a result of development of the device considered in this research, and impact as a result of the methods developed to analyse and optimise the device.

The primary intended impact of this research will be on the communities that the device will ultimately serve. As stated in the project summary, the device has a range of potential end uses including desalination, power generation and agriculture. As a particular example, if the device is used as part of a desalination system, initial predictions suggest that it could supply 200-300 people with safe drinking water. The potential impact of this is clear. The Joint Monitoring Programme (WHO / UNICEF report) states that in 2015, 663 million people still lack improved drinking water sources and eight out of ten people still without improved drinking water sources live in rural areas. As 44% of the world's population live in coastal areas (UN Atlas), a solution based on wave power would be of great benefit.

The health benefits are obvious (nearly 1 out of every 5 deaths of under 5's is caused by a shortage of safe drinking water), but the economic and social benefits are equally important - by releasing people from the excessive daily time commitment to collect water, their potential for spending time on economically active work increases. 40 billion hours a year are spent in sub-Saharan Africa alone in collecting water (WHO) - a region with 48,000 km of coastline (UNIDO).

Whilst the majority of the communities that would benefit from this research are overseas, benefits will be seen in the UK too. There are a small number of UK residents in remote, off-grid locations that could benefit, but more importantly, UK based charities (Oxfam, UNICEF, WaterAid, Practical Action and many more) would benefit from development of a this device, offering them a cost-effective way of reducing poverty in remote coastal communities. Professor Paul Sherlock OBE, former director of Water & Sanitation Cluster, Oxfam UK states that in his experience, there are a huge number of potential Less Developed Country sites that would benefit from such a device, and has given this project his full support.

In addition, it can be argued that any project that lowers the carbon footprint of energy production is of benefit to the global community as a whole. The benefits in terms of sustainability of this project are clear, utilising materials that would otherwise have consumed energy and generated pollution in their disposal.

Beyond the benefits of the device itself, developers of other WECs or similar devices stand to benefit from this research. Software costs to analyse device behaviour can be prohibitive for small, start-up WEC developers. By publishing methods based on simple, largely open-source software, the collaboration will support such developers, permitting timely, low cost evaluations of WEC concepts. This can help to prevent unnecessary investment into developing unfeasible concepts, and provide cost-effective ways of improving/optimising device performance before costly prototyping/experimental development.