W2W Top Trumps

 

W2W power flow starts getting interesting when applied to specific examples of WEC. I've chosen historical examples to avoid looking like I'm giving investment advice!  We're going to play 'Top Trumps' with three very different devices: the Wave Star arm (above), Pelamis, and the LIMPET OWC.  I learnt new and surprising things while preparing this blog post. At the end I compare the electrical generators and show how 'electrical power' is very different for these three devices.

 

Introducing W2W power flow diagrams

 

Wave to wire (W2W) power flow diagrams are interesting because they: 

• Provide a level playing field for comparing wave energy converters (WECs).
• Describe the physics of the power capture mechanism.
• Make it clear what subset of the process is being modelled, which is useful for model design and interpretation of results. This gives insights into important work such as the US Wave Energy Prize and WECCCOMP.
• Highlight challenges specific to wave energy, which can inform design.

Case study: perfect incubation for wind

  

A question we often hear asked is 'Why isn't wave energy commercial yet? Is there something fundamentally wrong with it?' The question is both really interesting, and a pain to get asked: there is no simple answer, everyone has a different take on this, and often the person asking just wants a simple thumbs up or down. 

Wind energy can be a useful analogy, especially for those of us ancient enough to have watched as it 'grew up', and to remember the same types of doubts directed at it. There are several techno-economic ideas (see Glossary for definitions) that are familiar when applied to wind energy, which we can then use as lenses for looking closer at wave energy.

Where techno- meets -economics

 

Annual Energy Production. Where techno- meets -economics.  

But what are the devilish details along the way to coming up with one number that describes the power capture of a wave energy converter? And how does this fit into a conversation about commercial development? And what red flags 🚩🚩🚩should we be on the lookout for when trying to make sense of published numbers on wave energy converter performance? 

Wave Group Reports

 

 

In response to the 1973 oil crisis, Professor Stephen Salter (1938 – 2024) nudged the UK Department of Energy into funding wave power research. This led to the 1974 Wave Energy Programme, which funded several designs of wave energy device. Due to political unpopularity, funding of specific devices was abruptly and controversially terminated in 1983. During the years that followed, the Edinburgh Wave Power Group worked on projects for generic technologies. In the absence of academic funding, there was also more focus on commercialisation of technologies that had been developed during the funding programme, such as wave makers and digital hydraulics pumps.  

Professor Salter’s research lab, ‘the Portacabin’, had copies of all the documents associated with the Edinburgh Wave Power Project. As a PhD student, these reports were revered artefacts. They all had a particular look about them, even those authored by his researchers a decade after the end of the funding programme. Access involved knocking on the Portacabin door; promising to put them back into the right place; etc. A few years ago, Professor Salter decided to make this collection available to the wider world via the Edinburgh Research Archive. I had promised a link from my blog, but I didn’t get around to this, as I was disturbed by subsequent additions to the archive that weren’t part of the Portacabin collection. To get around this, here are the links to the archive items that I associate with the Portacabin. It’s worth looking at the main archive page if you wish to search by author or subject.

 

Can we make an investment case for wave energy?

 

This was the question put to the discussion panel in last week’s ‘MORE/COER Wave Energy Workshop’ in Turin (my first trip out of the UK in almost 3 years). It was one of those questions that often comes up over quiet caffeinated chats, yet is rarely voiced in a crowded room. 

WES conference notes - 2017

Here’s a list of the most interesting information to come out of the WES conference last week.

US Wave Energy Prize data released

It's all here. Thank you US DoE!