The graph above shows just how little electricity is actually generated from a very large tidal stream resource. The annual shaft power available to this 600kW rotor's swept area is 25.240MWh. The fluctuating green line running along the x axis represents the electrical output from one of the 600kW rotors belonging to the Marine Current Turbine (MCT) machine in Strangford Lough. It is generally accepted that a 1MW tidal stream generator like the Neptune Proteus NP1000 placed in a vigourous tidal regime like the Humber Estuary will generate 1000MWh of electricity so we can conclude that this single 600kW rotor will generate around 600MWh(e) annually. This electricity, assuming two ROCs per MWh(e) and a wholesale price of £50/MWh(e) will turnover around £100,000 in sales. It is difficult to see how any investor will get his or her money back after overheads are taken into account. The pro rata capital costs of installing the single rotor runs into £millions and taking 'economies of mass production and scale' into consideration will never change that.
Of course, MCT claims a 66% 'capacity factor' is a bit misleading and allows the potential investor to calculate the projected electricity generated fot the 1.2MW machine as being 1.2 x 24 x 365 x 0.66 = 6938MWh(e) when a maximum of only 1,200MWh(e) can be generated in Strangford Lough's tidal stream. Is it little wonder that to attract inward investment from the gullible that the denominator in the fraction has bee reduced by a factor of 5.8 to make the numbers look bettter!
From the potential shaft power of 25,240MWh(mech) MCT can only convert 2.4% of it into variable and intermittent electricity for sale.
However, the savvy investor turnover nearly six times more money from the same tidal stream regime by investing in Gentec venturi which will generate 11,400MWh(e) from the same vertical swept area.
The graph above shows the large variation in power available over a half lunar month and, in order to get 'something ' out of each tide MCT and indeed, all other tidal stream systems, except Gentec venturi, adopt a 'lowest common denominator' strategy. This means that MCT, Open Hydro , Pulse, Lunar Energy et al could adapt their systems to generate more electricity, and more returns for their hapless investors, but choose not to do so. Just because a company is good at duping its government out of £millions of taxpayers' money does not mean that the company is good at generating large amounts of low cost electricity.
It is likely that you will never see any significant return on your investment in all real time tidal generating companies. If you still want to invest in tidal stream, Gentec venturi, has several key advantages over other other tidal stream systems. These include:
One day all of our electricity will be generated from deep ocean pelagic wave power. This massive renewable energy source.will supply all of our existing fossil and nuclear thermal power stations with renewable heat to raise 'green steam' without burning dwindling supplies of fossil fuels or splitting atoms.
Again the key advantages of using Gentec WaTS include the same as Gentec venturi
When there are no fossil fuels left to burn and no suitable fissile material left to split, if there is still human life Earth, all electricity will have to be generated this way.
www.wipo.int/pctdb/en/wo.jsp?WO=2010064041
The sooner we start generating 'greenheat' from wind wave and tidal resources and supplying it to our thermal power stations - the better it will be for mankind and investors' bank balances. The table below demonstrates just how much money can be made by using wave power in Scottish waters which attracts a premium of five ROCs per MWh(e).
Investing £8.4 million in a 10MW Gentec WaTS' power system will realise a clear profit of over £25.5 million in the first year of operation.
http://www.wipo.int/pctdb/en/wo.jsp?WO=2010064041