Data+Set+1


 * Internet Sourced Data:

Rf S1.1. ** // The presentation Gives an introduction to Offshoe Windfarms. // > Selection of support system depends on water depth, cost of the system, environmental loads (wind, wave, storm, seismic), size of turbines. // > 1) 7.5 MW wind farm, 1.5 MW turbines : > 5 km from coast – 4.9 US cent/kWh OR, 30 km from coast – 6.9 US cent/kWh > 2) 200 MW wind farm, 1.5 MW turbines : > 5 km from coast – 4.1 US cent/kWh OR, 30 km from coast – 4.4 US cent/kWh // > // Turbine (w/out tower): 17-40% // // > Tower and foundation: 28-34% > Electrical grid: 9-36% > Other: 6-17% //
 * // Wind speeds are higher //// furthest from the coast. More productivity can be achieved in deeper water. //
 * // Infrastructure requirements : //// Multiple wind turbines, Bottom mounted foundation, Electrical grid between turbines, Power cable to shore Infrastructure for operation & maintenance. //
 * // The barge crane must have the lifting capacity and reach to facilitate the installation. //
 * // Different options in terms of structural systems : Artificial island, pontoon, steel piling, truss system, gravity caissons, spar buoy.
 * // Cable laying : Triple core cables to facilitate single cable for transmission. Local transmission grids are created at the wind farm location, this requires that a sub station be provided at offshore location. By doing this a single cable can be laid out towards shore instead of laying out multiple cables. Marine cable laying ships are used to place the cable offshore. //
 * // Project Cost can increase from //// ~15%-100% when depth doubles (from 25 ft to 50 ft). Hence, going into deeper waters may be highly productive in terms of energy production but is offset by high installation costs. A sample European study (1997) explains this factually:
 * // Capital Cost breakdown for offshore windmill projects:- //

//**1.** Drivers for demand of offshore renewable: 28 key US states use 78% of the electricity in US. Marine energy resources are located close to major cities. Currents : Force constant in a direction for at least a few hours. The structure must support a completely submerged turbine. Tidal ranges are longer in the Northern Lattitudes. Waves: Force reverses every 5-20 seconds. The supporting structure can be floating, fixed, or submerged. Waves are larger in the Northern Lattitudes and west coasts. //From the above graph it is evident that in most countries Wave followed by Tidal energy source among all Marine energy sources has gained highest importance. // //**4.** The presentation talks about a different kinds of systems that are currently being considered for commercial use. The systems really vary and hence, the basic concept behind designing supporting structures for each would vary case by case. Thousands of concepts and patents on ocean technology are being pursued today, however, while a few have made it to the full scale prototype versions, there are no commercial projects yet// // **5.** A number of Governments in the Western world have put up ambitious targets to achieve certain percentage of their power production through renewable sources, chiefly wind power. Eg, USA, DOE 20% Wind Scenario Estimates 54,000 MW from Offshore Wind by 2030. In UK, 1,135 MW have been installed by end of 2007 with targets of 150000 MW by end of 2030. ↑ Turbine Supply Shortages ↑ Steel and copper price increases ↑ Regulatory Uncertainty ↑ Euro/$ Currency Exchange Rates ↑ Project Risk Uncertainty (public acceptance, reliability issues, insurance, unstable policy) ↑ Increasing fossil prices Some of the key Downward Cost Driversare : ↓ Learning Curve Effects ↓ Mass production ↓ Infrastructure development ↓ Experience lowers uncertainty ↓ Land-based learning ↓ High reliability components ↓ Multi-megawatt turbines ↓ Optimized offshore systems All these projects are within 30m of water depth. // // **8.**The estimated US resources in terms of offshore wind are: shallow 0-30m water depth (commercially proven technology) has the capacity to generate 430GW, transitional 30-60m has the capacity to generate 541GW (currently in demonstration phase) & deepwater 60-90m has the highest potential capacity to generate 1533GW. Again, the simple reason why the deepwater wind sources have not been tapped is because of the extremely difficult conditions for project execution. // // **9.**Most common type of offshore wind turbine foundation is Monopile foundation. The pile is driven or drilled 25-30m into sea bed but this system is possible for Stiff soils only (e.g. sand). Some other engineering facts are : 4.5 - 5 m diameter steel tube typical, Wall thickness 30 - 60 mm, Minimal Footprint, Water depth experience to 25-m. //**11.** Gravity based foundations depend on the sheer weight of base to keep in wind turbine in place. The structure can be both steel or concrete. To facilitate Installation and transportation, the structure may be hollow and may be ballasted once on site to make it sit on site on the desired location. **10.** The floating wind turbine concept is not that well proven technologically. The main advantage of floating wind turbine is the use in deep water. The conventional models of spar, TLP and floating barge are the more popular versions of the structure being adopted in the industry currently. // // **12.**in Summary of the Offshore renewable future : 100+ marine energy companies and concepts with no convergence of technology. Regulatory bottlenecks and uncertainty. Offshore wind is abundant on West US Coast. Deep water is the primary challenge. 2100-MW of shallow water wind projects are proposed in Eastern states (Currently commissioned). // // Deepwater technology (floating wind turbines) is in the early stages of development. Commercial systems are 10-years away. //
 * Rf S1.2. [[file:future trends in offshore renewables.pdf]]**
 * 2.** Wave and Currents as a comparative source:
 * 3.** Marine Energy participation by country (does not include wind energy)//
 * 6.** Some of the key Upward Cost drivers for offshore wind turbines are :
 * 7.** Below is a summary of the US offshore wind projects :
 * 10.** Multi pile systems is a highly commercially viable option since this kind of system is the most prevalent systen in the well developed offshore oil and gas industry. In this kind of structure a welded steel jacket is connected to the wind turbine turbine by welding connections on site. The structure is typically used in softer soils and can be used for deeper water depths. //

// **1.** The presentation talks about electrical transmission for offshore wind energy projects. The transmission of electricity forms a major cost of the project execution and should be given due importance. // // **2.** The presentation focuses on UK. Out of the 70TWH aimed to be produced from wind sources in UK 50TWH has to come from offshore. This means that apart from setting up the wind farms, a lot of work and investment shall have to be made in terms of transmission. // // **3.** Usually at a large wind farms shall be connected to the onshore locations via offshore substations to reduce the number of transmission cables required to be laid. // // **4.**The concentration of the generating units hence, plays an important role in the cost of the transmission. Gradually, as the number of generating units increase with an increase in concentration in general, the Capital expenditure reduces. //
 * Rf S1.3. [[file:electrical infra for offshore development.pdf]]**

// **1.** The presentation is about the prospects of Rhode Island, as a source of Offshore Wind energy. **4.** // No deep water sources exist close to RI shores for utilising ocean thermal energy. The tidal current speeds are lesser than 1.5m/sec hence, tidal energy cannot be utilised.
 * Rf S1.4. [[file:potential windfarms around RI.pdf]]**
 * 2.** In terms of wind resources, there is abundant supply but each site has its own disadvantages and advantages ranging from extreme waves, costly structure (deep), limiting the seaward extant, close to breakwater.
 * 3.** As a result of the study, it was found that the wave and wind energy is the most likely source worth investing in. Wind energy has the capacity of 685 MW while wave energy can go up to 40.8 MW.
 * 5.** Wave energy has potential for commercial development for RI. Estimate of power production potential for 5.7 kW/m Annual avg wave power per m of wave front off Block Island. The average size of a unit would be 30m (100ft) which would produce 40.8 KW power annually or 357MWhr per year (operating at 40% efficiency).
 * 6.** The offshore renewable source with highest commercial viability with the available technology seems to be Wind Energy. In the study different RI areas were studied and it was found that upto 685MW can be produced using wind as a source. Out of this, further sites were selected to geerate 150-220 MW.
 * 7.** Cost per MWHr for Winds $96 to 137 while for wave energy it is expected to be $630.

//The paper talks about future energy potential in offshore terms both for renewables and non-renewables in USA.//
 * Rf S1.5. [[file:example of offshore renewable technologies.pdf]]**
 * Rf S1.6. [[file:offshore norway.pdf]]**