Hello Steve, Near the Shetlands, a rather beautiful and heavy prototype has been using hydraulic cylinders and oil for driving a generator placed on the shore. I do not know where they stand now. I think the project is frozen. Best,
J de Mevius Stingray Tidal Stream Generator (Patent protected including US Patent 6731018) Stingray is designed to extract energy from water that flows due to tidal effects - tidal stream energy. It consists of a hydroplane which has its attack angle relative to the approaching water stream varied by a simple mechanism. This causes the supporting arm to oscillate which in turn forces hydraulic cylinders to extend and retract. This produces high pressure oil which is used to drive a generator. ----- Original Message ----- From: "Steve Gregory" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Monday, November 21, 2005 3:44 PM Subject: FW: [microhydro] Re: Efficiency of micro hydropower vs. large scale > Here is the guru's opinion on your opinion > cheers > > Stephen Gregory, M.A.Sc., P.Eng. > Alternative Hydro Solutions Ltd. > > -----Original Message----- > From: Brian Hollingworth [mailto:[EMAIL PROTECTED] > Sent: Monday, November 21, 2005 9:38 AM > To: 'Steve Gregory' > Subject: RE: [microhydro] Re: Efficiency of micro hydropower vs. large scale > > Steve, > > Just reviewed my notes. Sorry for scaring you the other day be appearing not > to know what I'd already proposed. Happens all too often unfortunately. I > had looked at losses. Your guy is missing the point that there a positive > displacement system. Quite understandably so, as he is probably not aware > that such devices exist. > > Preaching about established technology without reference to what is hiding > in the wings is like a red rag to a bull for me, so be assured this will now > get my whole attention. > > What I am proposing is nothing more than a hydrostatic drive, which in and > of itself is roughly 95% efficient, more so than oil (the likely source for > any figures) as there are few water based values available. > > More shortly. I'll call. > > Good Day > Brian Hollingworth > HASTEC Engineering Inc. > 45-8 Hannover Drive > St. Catharines > ON L2W 1A3 > Canada > Tel: 905-687-9194 > Fax: 905 687 9988 > Mob: 905 380 4897 > > > -----Original Message----- > From: Steve Gregory [mailto:[EMAIL PROTECTED] > Sent: 20-Nov-05 07:58 > To: Brian Hollingworth > Subject: FW: [microhydro] Re: Efficiency of micro hydropower vs. large scale > > Do you agree with this guy honestly? > > Stephen Gregory, M.A.Sc., P.Eng. > Alternative Hydro Solutions Ltd. > > -----Original Message----- > From: [email protected] [mailto:[EMAIL PROTECTED] On > Behalf Of oso954 > Sent: Saturday, November 19, 2005 5:03 PM > To: [email protected] > Subject: [microhydro] Re: Efficiency of micro hydropower vs. large scale > > Steve, since you asked for comments, I will give you mine. You > probably will not agree with them, but I will post them anyway. > > The concept of pumping water to a turbine is not unique. There is at > least one other person on this board that has been working on the > same concept. The point that both of you seem to be missing (at least > in your posts/websites) is that there are large losses involved. Your > system will only generate about 50-66 percent of the power that > direct drive turbine/generators would. You are in essence trying to > build "pumped storage", without the storage, and your > losses/effeciency will be similar. > > There may be some sites, where the unique variables at that site, > make a pumped system viable/desirable. However, in most cases you > will produce more power, for less dollars, by eliminating the pump > and the extra turbine, and driving your generator(s) directly from > the in steam turbine(s). > > Combining the electrical output of several generators is much easier > than producing a balanced hydraulic drive system. If one pump/turbine > is spinning slightly faster and producing higher pressure, it will > severely reduce or kill the flow from other units. So this will > mandate some type of pressure regulation scheme, which will increase > the parasitic loss of the system. > > Your other choice is to pipe each pump separately to each nozzle of > your on shore turbine, which limits your network to the number of > nozzles in your onshore turbine. And hopefully, the turbine will > tolerate the imbalance caused by different pressures on the nozzles. > > And, last, but not least. Your website comment "Any grease used > during the assembly would be canola based and therefore > environmentally friendly " is shocking to me. Discharge of x amount > of canola oil/grease into a stream or river is just as harmful as a > like amount of petroleum. While vegetable oil might breakdown > and "disappear" somewhat faster than petroleum, the initial impact is > just as bad and should be avoided at all costs. > > Ian, I would suggest that you hire an engineering firm to consult on > the design of your 20mw hydro units. Whether a dam is used (or not) > for hydroelectric generation depends on many factors. Most dams were > not built solely for electric generation. Flood control, more > consistent summer flow, domestic water supplies, transportation, etc, > are all viable reasons, and often the primary reasons for a dam. > Once the commitment to build the dam has been made, tacking a > powerhouse onto it is a very logical thing to do. It "helps pay for" > the dam. > > Every hydro installation needs to be designed site specific. If a "no > dam" solution will work at a specific site, that would be the > recommendation that a good hydro engineer would make first. Why > would he recommend spending the big bucks, if it is not needed ? > There are many hydro plants that are built without dams (e.g. Niagara > Falls). But since most people do not camp or boat near them, they > never see them. > > Dams do change the environment. That is un-avoidable. Most of the > talk you hear is of the negative impacts generated by older dams. > Engineers have developed many ways of mitigating (but not totally > eliminating) the negative impacts. There is far less talk of the > many positive/beneficial impacts that dams do have. > > Your approach of looking for the electricity without the dam may > actually be doing a dis-service to China. If they need help > developing the electricity, they probably need the help developing > the other uses of the river in ways that would benefit the country. A > good hydro consulting firm could look at all the aspects and then > present you with the appropriate solutions/alternatives. > > The bottom line is that the 20mw you are looking for is 20,000 units > of 1kw each. Which would cause a smaller cumulative environmental > impact, 20,000 units spread up and down the river, or one large unit > (with or without dam) within a much smaller geographic area ? While > the best solution may lie somewhere between those two extremes, the > comparison helps put the problem in proper perspective. > > > > > > > > > > > > Does your company feature in the microhydro business directory at > http://microhydropower.net/directory ? If not, please register free of > charge and be exposed to the microhydro community world wide! > > NOTE: The advertisements in this email are added by Yahoogroups who provides > us with free email group services. The microhydro-group does not endorse > products or support the advertisements in any way. > > More information on micro hydropower at http://microhydropower.net > > To unsubscribe: send empty message to [EMAIL PROTECTED] > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! > > NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. > > More information on micro hydropower at http://microhydropower.net > > To unsubscribe: send empty message to [EMAIL PROTECTED] > Yahoo! Groups Links > > > > > > ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. 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