Oceans of energy pdf

Specialized crew is employed to man the oil platforms, and they work in 8 or 12 h shifts. Supply ships provide rations, other provisions and spare parts to the oil platforms every week.

This is due to the high capital cost of the platforms, high costs of operation, expensive manpower, high cost of transportation of oil by pipelines and recurring costs in ferrying crew to the oil platform.

This makes offshore oil more expensive than onshore oil. The distance from the shore and the depth also impacts the cost of oil production. As a general thumb rule, the cost increases with increasing depth of water and decreases with an increase in the size of the platform due to economies of scale.

The per day cost of drilling in oilfields located in shallow waters was about , USD between and The cost for deep-water drilling was in the range of ,—, USD per day during the same period. The investment in offshore oil exploration and production is a function of the market price of oil. Global investment in offshore oil production increases with the spot price of oil and when the forecast for future oil prices in the short term is high. There is also a strong correlation between oil prices and orders for offshore rigs as an increase in oil price increases the prospects of higher profit from offshore oil extraction.

On the other hand, a fall in oil prices leads to pulling out of investment from the global market. However, these investments are known to return when the prices of oil climb back and the payback period for investments in offshore oil becomes shorter.

It is estimated that breakeven prices for offshore oil produced in shallow waters for Brent oil is the range of 70 USD per barrel, and for deep-water and ultra-deep- water projects are around 77 and 64 USD, respectively Goodridge The overall trends observed over the past few years indicate that investment in offshore oil and gas industry is expected to increase with growth expected across the entire spectrum of the industry ranging from offshore oil rigs, FPSO and underwater ROVs.

The exploration, development and production from an offshore gas field is similar to that for offshore oil. Large offshore gas fields are found in the Persian Gulf, and most of the production in the North Sea comes from the Troll and Ormen Lange gas fields. It lies in relatively shallow depth of about 65 m and is jointly owned and operated by RasGas and Qatargas. The average production from this field is about 77 million tonnes.

It is spread in an area of km and is estimated to contain tcf of natural gas reserves. It is operated by Pars Oil and Gas. The Shtokman gas and condensate field located about in the Barents Sea off the shore of Russia; Mamba Complex located in the Rovuma Basin off the shore of Mozambique; and the Kish gas project located near the Kish Island in the Persian Gulf, Iran, are other large offshore gas fields in the world Duddu a.

Drilling and extraction of offshore natural gas follow the same process as that for offshore oil but unlike oil which has to be pumped up, natural gas flows up to the production platform automatically. Often oil and gas are found together, and these are separated at the wellhead into liquid and gas and stored separately. If the natural gas fields are close to the shore, the extracted gas is carried from pipes laid on the seabed to the shore for processing.

The extracted offshore natural gas is separated into dry natural gas and is then converted to liquid natural gas LNG using onboard equipment. Similar to FPSO, a FLNG vessel bypasses the need for laying expensive undersea natural gas pipelines and for transporting the natural gas to the shore. FLNG vessels are deployed in isolated and small gas fields which are located far away from the shore. The received LNG is stored in tanks and is converted to natural gas by bringing it back to ambient temperature and pressure.

This is done in a controlled manner, and the flow rate is adjusted to pump the converted gas from the vessel to the receiving terminal on the shore through underwater pipelines. They are composed of molecules of methane gas which are trapped inside water molecules.

Methane hydrates were formed over time by decomposing biological material and microorganisms which were buried deep under the ocean floor. Methane gas produced by this decaying matter slowly rise to the upper layers of the sediment in the form of gas bubbles.

Such conditions are found in waters which are more than 35 m deep. Areas which are closer to the continental shelf have large deposits of decaying organic matter as compared to the high seas. Therefore, methane hydrates are mostly found near the continental margins at water depths between and m. Methane hydrates contain methane, which are the basic ingredient of natural gas and are a potential source of clean energy.

Methane hydrates have a high energy density. One cubic metre of methane hydrate can hold around m3 of methane and 0. The US Energy Information Administration estimates that worldwide reserves of methane hydrates range from 10, to , trillion cubic feet EIA These estimates overshadow the combined global reserves of oil and natural gas, and hence, methane hydrates are attracting widespread global attention. Reserves of methane hydrates are believed to be spread globally across the oceans and hold great promise for hydrocarbon deficit countries such as China, India, Japan and Korea.

The process of extraction of methane hydrates is complex and expensive. Methane hydrates are inherently unstable and decompose into water and methane when exposed to lower pressure and ambient temperature. This implies that if there is an attempt to bring methane hydrates out of their natural location, it disintegrates into methane which is then released into sea water. The solid ice-like crystal therefore has to be extracted in such a way so that there is controlled release of methane into the production well without the gas escaping into the sea water.

Although the technology to mine methane hydrates was first tested under labora- tory conditions in , pilot projects for extracting methane from methane hydrates have only yielded results in the last few years. Japan first tested the technology for production of methane hydrate in deep water located in the Nankai Trough in Methane hydrates were depressurised by pumping water after drilling a well into the sea surface.

This released the gas into the well at a rate of 20, m3 a day. It is reported that the well was later closed due to sand clogging Jones China was also successful in extraction of methane from methane hydrates in May Although this may be a considered a big technological breakthrough, China expects commercial production of methane hydrates to commence by Japan which is also continuing exploration and efforts for harnessing methane gas expects to commercialize production between and While commercial production of methane hydrates is still decades away, the technology is being viewed as promis- ing.

Further, as methane is a clean energy source, many countries such as China, Japan, India, South Korea and Taiwan are planning to tap into these energy resources from the oceans in the near future. Apart from technological challenges in extraction of methane hydrates, methane is known to be a highly potent gas which has a large impact on global warming. Methane is 20 times more potent than CO2, and the accidental large-scale release of methane during extraction of methane hydrates may cause an increase in the rate of global warming.

Natural emission of methane is already a major cause of concern as large quantities of methane has been observed to be escaping from melting permafrost in polar regions and from continental shelves in the oceans.

Release of methane into sea water leads to an increase in the concentration of CO2 in sea water that making it more acidic. This may affect the physical properties of sea water such as lowering of oxygen content in water which may be dangerous for marine organisms.

It is also feared that extraction of large quantities of methane hydrates may lead to collapse of ocean floors which may trigger underwater landslides and tsunami. However, these threats can be eliminated with advances in technology.

Despite many technological challenges, it is economics which would dictate the pace of exploration and production of methane hydrates. However, as the price of oil and gas increases over time, and as technology improves, it is predicted that extraction of methane hydrates would become financially attractive.

Methane hydrates are important potential sources of energy but it needs to be remembered that it is still a fossil fuel and has associated GHG emissions. It may be possible to replace coal and oil with methane produced from methane hydrates in the short term but burning of methane would continue to emit CO2 and in the long run, and the use of methane hydrates is detrimental to a net zero carbon world. Therefore, extraction and use of methane hydrates have to be carefully weighed against investments in renewable energy sources such as wind and solar which have zero emissions.

Some of the offshore platforms such as those in the Gulf of Mexico are located in areas frequented by hurricanes and cyclones, and those in the North Sea are subject to severe weather conditions with freezing temperatures and rough seas. Oil and gas are extracted at high pressure and temperature which places significant demand on the quality of material used and workmanship especially for the sub- merged equipment.

Pressure increases rapidly with increasing depth, and it is about bar at a depth of m. The possibility of malfunctioning of equipment, onboard explosion due to the high working pressure, limited capability to control fire and the risk of damage to the structural integrity of the platform are omnipresent despite the large number of safety measures which are inbuilt on these platforms.

Confined spaces and the risk of vapour build up also poses an ever-present danger to human life. Considering that these rigs are located several miles into the sea, the ability to provide assistance in case of an accident on the platform is severely restricted as the fastest possible mode of transport is by helicopters which are often hours away.

Further, rescue operations may not be possible in inclement weather or during periods of low visibility. This makes working on an offshore oil platform extremely hazardous and challenging. These are natural seepages, leakages during extraction and drilling, leakages from transportation of oil in underwater pipes and from oil tankers and leakages from consumption of petroleum. Global estimates of oil flows into the sea are estimated to be upward of 1.

It is reported that about half of the oil that enters the coastal environment comes from natural seepage of oil and gas Woods Hole Oceanographic Institution With only a fraction of that space covered by solar panels, a lot of energy can be generated — as much as needed. The first offshore solar farm in the world is already installed by Oceans of Energy in on the North Sea, and still in operation today. The same technology can be applied in any water, for any coastal region or island in the world.

The future lies at sea. Abstract Ocean waves may potentially contribute one TW to global energy supply. The time variablity of wave energy can be smoothed by integration with the general energy supply system.

Many different … Expand. Offshore wind energy prospects. In last two years offshore wind energy is becoming a focal point of national and non national organizations particularly after the limitations of fossil fuel consumption, adopted by many developed … Expand. Tidal energy: Promising projects La Rance, a successful industrial-scale experiment. In some few special areas of the world, the range of the variation of the sea level due to the tide can be impressive.

For centuries man has been harnessing this energy with the operation of tidal … Expand. View 3 excerpts, references background. Deep, cold seawater has long been recognized as a valuable energy resource, and early studies in the 's, motivated by the energy crisis, identified its advantages for coastal air conditioning.

Combined power generation with wind and ocean waves. It is often advantageous to generate power with combinations of wind and ocean waves. In fact ocean waves, their generation, propagation, dissipation are directly related to wind velocity and its … Expand.

Electricity from the Sea. View 4 excerpts, references background. Air conditioning with deep seawater: a cost-effective alternative for West Beach, Oahu, Hawaii. Conference Proceedings. Deep cold seawater can be a practical and economically viable source of cooling in a centralized air conditioning system. View 1 excerpt, references background.

A Review of Existing Data. It is basically converts thermal energy into kinetic energy through turbine. The cold water is pump through a the ocean.

Now a day solar to drive a turbine then it generates electricity. He also gives a detailed working of closed cycle OTEC 1.

The hot in 3. It is water is pump through a depth metre of the basically converts thermal energy into kinetic energy ocean to condense.

The constant use of vaporization through turbine. We use sea water as a working fluid and condensation is used to drive a turbine then it in open cycle of ocean thermal energy conversion. The warm surface of sea is exposed to vacuum and causing it to boil and generate the steam. The hot in ammonia are flow past one another in heat exchanger so that hot water gives its heat energy to ammonia making it to boil then vaporisation of ammonia flow through a turbine then making it to rotate.

After that a generator converts that energy into electricity. Now the warm ammonia should be condensed in condenser through cool water of ocean depth comes through the pipe. Other heat exchangers which cool the ammonia back down to its original temperature.

Ammonia is capable to reuse. The warm sea water enters into the vacuum chamber. Then it flash evaporated into steam this is like an open cycle. A low boiling point of working fluid is vaporised into a steam which runs the turbine to produce electricity. This process is similar to close cycle.