greenheatman Posted April 23, 2007 Report Share Posted April 23, 2007 As you've already dismissed a time-served engineer and at least two people who have studied maths to university level as not qualified enough to understand your graph it might take a couple of days I, too, am a time served Electrical Engineer (Electronics) and have been for over 34 years, but the fact remains that the 2MW lunar energy device can only generate, in a very high tidal stream maxxing out at 5.6m/s (Bay of Fundy), at full capacity for 3.5 hours putting just 7MWh(e) onto the grid. During the 'nadir of Neaps' this same device in the same location cannot reach full capacity generation putting a maximum 350kW(e) onto the grid. So the surplus power discarded during Springs is worthwhile saving to maintain a constant output. Can we at least agree on that? Simply put, a bog standard marine turbine is pretty worthless because, despite the output being predictable, it can only deliver electricity, at varying capacities between 2MW and <350kW, onto the grid usually outwith peak demand times. How does that help to save our planet? Quote Link to comment Share on other sites More sharing options...
Malachy Posted May 5, 2007 Report Share Posted May 5, 2007 Just for folk's interest. We have an article in this month's Shetland Life magazine on tidal and wave power and its potential in Shetland. You can read it online here http://www.shetlandtoday.co.uk/shetlandlife/content_details.asp?ContentID=22191 if you haven't already bought the magazine, that is. It may disappoint a few people who were thinking that marine energy was a viable alternative to wind power in the near future. Quote Link to comment Share on other sites More sharing options...
greenheatman Posted May 5, 2007 Report Share Posted May 5, 2007 It may disappoint a few people who were thinking that marine energy was a viable alternative to wind power in the near future. Well, it certainly is not viable when all that numpty academics can come up with is articulating joints pushing hydraulic oil about - when the waves are energetic, and simple electro-mechanical windmills-under-the-sea type devices. The sea snake 'farm' of 2 square kilometres - surely they mean 2km squared - has, in the N. Altantic over an area of 4million m2, 720GJoules of energy available and will extract a few MWh(e) from that enormous resource - intermittently. What I am disappointed in is the lack of imagination! Quote Link to comment Share on other sites More sharing options...
islandhopper Posted May 5, 2007 Report Share Posted May 5, 2007 It may disappoint a few people who were thinking that marine energy was a viable alternative to wind power in the near future.Why at all ??? The only thing one has to do is to read the last subtitle and the following two paragraphs very, very carefully ... the passage about viabilty and "he did not disagree" ... sorry, but he simply said they are not in competition and "We need all of them!" ... having in mind that he is a nice chap and that the Pentland Firth with the capacity available there is closer to "his" interests as is any site in Shetland one might consider. Quote Link to comment Share on other sites More sharing options...
Malachy Posted May 7, 2007 Report Share Posted May 7, 2007 It was the "near future" bit that I think was important. The suggestion is that it will be decades before the technology is anywhere near to being able to provide the amount of power Viking Energy is talking about. And that is not soon enough. Quote Link to comment Share on other sites More sharing options...
islandhopper Posted May 8, 2007 Report Share Posted May 8, 2007 Well, Malachy,"near future" is a somewhat vague idea.We should not forget that is was a smaller step from the Wright Brothers' first little hopp to the first economically successfull trans Atlantic flight compared with Jules Verne's dreams about travelling to the moon and the first step down there ... Despite that there is something different: For the first time within he whole discussion about renewables we see the North American companies, both Canadian ans US, throwing their money and development potentials into wave and tidal energy developments. With regard to that: 5 years ... near future or tomorrow ...???5 or 6 years ... that's within the range of getting planning permission for the VE project ... Quote Link to comment Share on other sites More sharing options...
crofter Posted May 9, 2007 Report Share Posted May 9, 2007 "In Shetland, where some of the best conditions for both wave and tidal power exist, the range is 75MW to 400MW for wave power, and less than 75MW to 200MW for tidal generation." From this article "Marine energy potential is limited": http://www.shetlandmarine.com/2007/07%20Environment/marine_energy_potential_is_limited.htm Quote Link to comment Share on other sites More sharing options...
Malachy Posted May 9, 2007 Report Share Posted May 9, 2007 Yes, that will certainly give folk something to think about. It seems to me that marine power has just been something people talk about because they don't like windmills. They actually know little about the technology or the potential for electricity production. And they certainly don't realise how far behind the technology is.That's not to say that we shouldn't be investing heavily in research, but that the level of urgency required simply doesn't allow us to sit back and wait for technology to come along. Quote Link to comment Share on other sites More sharing options...
islandhopper Posted May 9, 2007 Report Share Posted May 9, 2007 oh oh ... I don't want to discuss four figures picked out by the media but what you should have mentioned when quoting the Maunsell/metoc report is the fact that it is bound to "assess the likely effects that meeting or exceeding the estimated 1,300MW of marine renewable energy capacity would have on the environment." ... 1,300MW of (all) marine renewables only! ... for the whole of Scotland. Edinburgh Unsiversity in Matching Renewable Electricity Generation With Demand for Scottish Executive, too, is calculating up to 3000WM from wave plus 750WM from tidal current in Feb 2006. The difference between 3750WM and 1300WM is due to political limits set by Scottish Executive as a guideline for this Maunsell/metoc report in question ... and the media could have known that (edit, just for a little smile):... an interesting detail of the Edinburgh University scenario calculation is the outcome of the area (5) scenario with a best long-term local matching of 98% for a generation mix of 150MW wave, 60MW tidal current, 60MW offshore wind leaving 450MW onshore wind for the whole of Shetland ... Quote Link to comment Share on other sites More sharing options...
greenheatman Posted May 14, 2007 Report Share Posted May 14, 2007 Pete Bevington 9 May, 2007 SHETLAND could produce no more power through wave and tidal power than it could generate from the proposed Viking Energy windfarm, it emerged yesterday (Tuesday). A team of three consultants visiting the isles yesterday told a select group of invited guests that current assessments suggest that Shetland could produce a maximum of 600 megawatts from the wave and tide combined. Consultants Faber Maunsell and Metoc have been commissioned by the Scottish Executive to carry out the SEA (Strategic Environmental Assessment) Directive to work out the potential of developing marine-based renewable energy throughout the west and north coast of Scotland. Their "desk top calculations" based on statistics and broad brush figures suggest that Scotland as a whole could produce between 525MW and 1,800MW from wave power, while tidal power would only generate between 75MW and 800MW. In Shetland, where some of the best conditions for both wave and tidal power exist, the range is 75MW to 400MW for wave power, and less than 75MW to 200MW for tidal generation. The low figures surprised the assembled group from Shetland Islands Council, Scottish Natural Heritage, the Shetland Renewable Energy Forum and the RSPB, but reflect the environmental constraints facing the development of marine energy. SIC development manager Aaron Priest said: "This gives an indication of the reality of the development of green technology and the resource once you take into account environmental factors. "The size of the overall resource is not as big as some people would expect when you build these factors in." Pete Ellis, of RSPB Shetland, was still digesting the report yesterday afternoon. He said the consultants' presentation was "vague", but that was probably because of the state of knowledge about the technology involved which is still at an early stage of development. The joint Viking Energy/Scottish and Southern Energy windfarm proposed for north and central Shetland is being designed to produce 600MW of electricity, though as Mr priest explained, it is the amount of time that any installation can produce power is the key factor in understanding its true worth. Yet again the 'experts' have got it wrong! The consutants' remit was to assess the potential energy in tidal streams and waves NOT the potential energy in tidal stream and waves using simple and existing energy convertors. Had they stuck to their remit, they would have discovered that the potential power available from tidal stream is out by a factor of >100 and the potential from waves >1000 I note that Aaron Priest has swallowed this guff hook line and sinker, but it had the desired effect of making the 600MW wind farm look viable! I wonder why? Perhaps, the conclusion that 'wind beats all' was already written for the consultants when they took on the contract[/i] Quote Link to comment Share on other sites More sharing options...
Ghostrider Posted May 14, 2007 Report Share Posted May 14, 2007 How's that prototype GENTEC venturi being constructed at that undisclosed location coming along? Sceptics of the quoted figures for thermal loss from the stores to the heating of seawater to steam process, and of the quoted durability/longevity of the stores themselves would like to be proved wrong. Quote Link to comment Share on other sites More sharing options...
BigMouth Posted May 15, 2007 Report Share Posted May 15, 2007 How's that prototype GENTEC venturi being constructed at that undisclosed location coming along? My £10 is still available. It is a rare thing indeed when someone wont accept FREE money Quote Link to comment Share on other sites More sharing options...
Evil Inky Posted May 16, 2007 Report Share Posted May 16, 2007 How's that prototype GENTEC venturi being constructed at that undisclosed location coming along?I wouldn't ask him embarrassing questions like that - you'll only provoke yet another tantrum Quote Link to comment Share on other sites More sharing options...
greenheatman Posted May 24, 2007 Report Share Posted May 24, 2007 How's that prototype GENTEC venturi being constructed at that undisclosed location coming along? Sceptics of the quoted figures for thermal loss from the stores to the heating of seawater to steam process, and of the quoted durability/longevity of the stores themselves would like to be proved wrong. It is all going well - I will be flying out on 1st November - it's a very long way! A composite material just 18mm thick has zero thermal conductivity ie k=0 so no losses there then Quote Link to comment Share on other sites More sharing options...
Ghostrider Posted May 24, 2007 Report Share Posted May 24, 2007 ^^^ Unless your ticket is for a Space Shuttle trip, anyplace else is a mere hop, skip and jump these days. so no losses there then Structural fatigue/failure excepted of course. Quote Link to comment Share on other sites More sharing options...
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