Realistically, the tidal energy resource that could be extracted is confined to a few regions in the world that have an exceptional resource.

The energy stored in the oceans is vastly more than Man could possibly use. The oceans convert the gravitational forces from the celestial bodies into mechanical energy, felt by the sea as it bulges to form the ebb and flow tides.
This kinetic energy can be transformed following similar rotor/turbine principles used to extract energy from the wind. Seawater is 800 times denser than air, therefore the energy available across a representative cross-section is also 800 times greater at the same speed. This means the swept area necessary to generate a given output from a tidal turbine will be substantially less than it is for a wind turbine.
A typical tidal current turbine might develop its rated power at little more than two m/s compared with 12m/s needed to achieve full-rated power for modern wind turbines. The logic follows that a one megawatt tidal turbine rotor would be less than 20m in diameter, compared with 60m for a one megawatt wind turbine, e4engineering.com said.
As the sun rises and sets and the moon comes and goes, tidal velocity drops and gains throughout the lunar day (24 hours and 50 minutes). Thanks to the sun and moon’s regular and predictable relative movements around the Earth, the electricity generated by a device can be predicted long into the future--unlike the unpredictable weather phenomena that drive the wind and waves. This is a powerful tool for negotiating with utilities in terms of matching the contract of the generator with future electricity supplies for the operator, thus enabling improved economic modeling of a system and increased security of supply for the future.
The dream is to assemble arrays of tidal stream rotors, generating hundreds of megawatts, built up in ’hubs’ around the UK and gently brought on-line as grid infrastructure is strengthened.
By deploying groups of generators in different locations around the coast, daily fluctuations in power output can then be smoothed out, achieving peak power output at a different time according to the local tides. In the UK, there is a difference of several hours between the high tide on the east and west coasts.
Realistically, the tidal energy resource that could be extracted is confined to a few regions in the world that have an exceptional resource. Estimates of a significant UK tidal resource of 22 TWh--representing about half the European extractable resource--correspond to about seven percent of the UK’s electricity demand.
The immediate future for commercial operation of tidal stream devices will see the costs of capital and operating expenditure fall at all plant capacities. This is because the near-shore locations will result in lower cable and burial/protection costs and reduced complexity of the foundations and moorings.
It is to be expected that new-generation technology will incur longer construction periods and lower load factors compared with conventional fossil plant, resulting in longer payback periods, with unit cost highly sensitive to the discount rate employed.
Project risks are associated with the civil engineering works required, and delays to the construction schedule having an eventual effect upon the interest charged during the construction period.
Furthermore, installations where the downstream current velocity is altered significantly across the width of an estuary may have consequences for the transport of sediment and ecosystems.
As power flux of flow is proportional to the cube of the velocity of the water in the flow, tidal schemes based on free-flow currents are expected to be certified to limit energy reduction in the flow to around 10 percent.

The European Wind Energy Conference (EWEC) kicks off this week in Athens, Greece. This year’s conference is a rallying call around wind power as a “No Fuel Solution.“ Emphasis is on how wind energy eliminates the economic impacts and risks associated with volatile and uncertain fuel prices, while providing an indigenous and real solution to Europe’s energy demands.
“Wind power has a unique characteristic: it requires no fuel. Therefore it has zero fuel price risk, zero fuel costs, no external energy dependence and extremely low operation and maintenance costs. Wind is power without fuel. Who can say no to that,“ said Ian Mays, Conference Chairman / Managing Director, Renewable Energy Sources (RES), UK, at the opening of the EWEC 2006 Conference.
The days of inexpensive and abundantly available conventional energy are over, said conference notables. At a time of rising energy prices, increasing demand, energy supply insecurity and climate change, it is often overlooked that Europe is the world leader in renewable energy technologies, the most promising and mature of which is wind power. Wealthy in wind energy resources, there is enough wind energy available in Europe to power the entire continent, solaraccess.com said.
“By the year 2010, 20.1% of Greece’s energy production will come from clean energy. The creation of a new legal framework in combination with the new spatial planning for the installation of Renewable Energy Sources systems in areas with high energy potential paves the way for large-scale investment,“ said Dimitris Sioufas, Minister of Development, Greece. “Greece ranks among the top ten places of the worldwide chart, which classifies countries according to how attractive they are for investments in wind energy. Wind power is a fast-growing energy sector, which boosts the economy and cares for the environment.“
Britta Thomsen, MEP, Vice-Chairwoman of ITRE Committee, European Parliament shared some stark figures about Europe’s increasing reliance on imported energy. Today, she said, 50% of Europe’s energy needs is presently imported and that share is likely to increase to more than 70% within two decades. By 2030, oil imports would rise from 76% to 88% and gas imports from 50% to 81%, compared to 2000.
“We are at a defining moment in the history of energy supply, and energy is moving to the top of the political agenda,“ Thomsen said. “Wind energy, together with other renewable technologies, can provide a significant and secure supply side solution.“
With the installation of a record 6,183 MW in Europe in 2005, wind energy has achieved the European Commission’s 40,000 MW target for 2010, five years ahead of time, according to Prof. Arthouros Zervos, President of EWEA. By 2010 the world market for wind power is predicted to double to 16 billion Euros per year. EWEA business forecast sees 180 GW of wind generating 12% of Europe’s total TWh requirements for 2020, and delivering 37% of all new EU generation capacity.

Saudi Arabia will decide soon whether to proceed with plans to raise capacity at its oilfields beyond the 2009 target of 12.5 million barrels per day (bpd), a Saudi oil adviser said.
The kingdom is on track to add 2.3 million bpd by August 2009, around 800,000 of which will be used to offset natural declines, said Nawaf Obaid, managing director of Saudi National Security Assessment Project (SNSAP).
’All of the fields are expected to come on stream around six months earlier than initial projections,’ Obaid said, commenting on his latest SNSAP report.
Saudi Arabia, which has a current production capacity of 11 million bpd, has fast-tracked oilfield expansion plans to raise its output capacity to 12.5 million bpd by 2009 to maintain spare capacity and meet growing world demand.
The first increment will come from Haradh field, adding 300,000 bpd of Arab Light crude by the second quarter of 2006, Reuters reported.
Saudi Aramco said earlier this month it has started pumping ahead of schedule from Haradh and Oil Minister Ali Al Naimi has said the extra crude would lift the kingdom’s output capacity to 11.3 million bpd by April.
Beyond 2009, Riyadh plans an increase of 1.35 million bpd--800,000 bpd to offset declines--to bring sustainable capacity to 13.05 million bpd by 2013, said the SNSAP report.
Obaid said the figures in the report were conservative for both expansion phases and that the post-2009 plan was expected to raise output capacity to 13.05-13.15 million bpd.
According to SNSAP, the first of the post-2009 projects would be a $1 billion expansion at Shaybah. A $500 million expansion at the Neutral Zone, which is shared with Kuwait, would add 150,000 bpd of Arab Medium crude by 2010.
’A decision to proceed with development is expected soon,’ the report said of the two projects.
An expansion of Moneefa field, expected to cost $5-$7 billion, would add 1 million bpd of Arab Heavy crude by 2013.
’The project is currently under consideration,’ the SNSAP report said, adding that the project depends on market fundamentals and progress in planned increases in Aramco’s domestic and international refining operations.
Saudi Arabia has been pumping around 9.4-9.5 million bpd.
Saudi Arabia holds the lion’s share of the spare output capacity of OPEC, which has faced calls from importing states to raise its output to prevent high prices from slowing economic growth.
Riyadh also has plans to overhaul and expand its refining operations at home and abroad. It will build two domestic export-oriented refineries with total capacity of 800,000 bpd.
According to SNSAP, the downstream projects would increase domestic capacity by 1.29 million bpd to 3.385 million bpd and capacity abroad by 1.075 million bpd to 3.1 million bpd--for a total refining capacity of over 6.480 million bpd by 2011.

Look right as you reach the end of the three-hour drive from Darwin and your eyes stick onto a big pile of yellow something.
Then your brain clicks into overdrive.
“This is a uranium mine, right? So that must be yellowcake.“
Then: “This is what the fuss was all about... this is what Saddam didn’t try to buy from Niger. And here it is, just sitting out here in the rain.“
Fortunately, though, the yellow something turns out not to be yellowcake--but sulfur, used to make the 280 tons of sulfuric acid which the Ranger mine’s processing plant needs every day.
At the gate we stop for security clearance, don goggles, hard hats and protective boots, and walk on to the site of Australia’s oldest operating uranium mine, bbc.co.uk reported.

Changing Traditions
Ranger exported its first barrels of uranium in 1981, and is now one of three mines operating in Australia.
The country has no nuclear energy program of its own, but even so, uranium arouses powerful and contrasting emotions here.
Ranger finds itself in a delicate ecological situation; since operations began three decades ago, the land around it has become Kakadu National Park, now one of the world’s most iconic conservation regions.
There has also been a sea-change in how the nation treats Aborigines. The mine’s owners, Energy Resources of Australia (ERA), now do not own the site itself, but lease it from local indigenous groups -“traditional owners“.
The identity of the yellow stuff was not the only misconception I found about uranium mining.
Friends had asked whether visitors needed lead suits and Geiger counters.
“Often people believe that radiation would be our primary health risk here--in fact it’s not,“ says Alex Zapantis, ERA’s manager of environment, safety and health.
“Uranium is actually not very radioactive, and it’s simple physics; the longer half-life something has, the less radioactive it will be by mass.“
The half-life is the length of time it takes for half the atoms in a sample to decay; the shorter it is, the more intense the material’s radioactive output.
The half-life of uranium-238, the mineral’s main component, is four and a half billion years.
“So as a consequence it has a very low specific activity,“ Alex continues, “and the only way someone could receive an unacceptable dose in our mine is through inhalation of quite large quantities of ore dust, which is very easy to monitor and quite easy to control.“
However like other heavy metals, uranium is poisonous--another reason to take safety seriously.

Into the Pit
The dustiest part of the process comes at the very beginning, when rock containing uranium ore is blasted into fragments.
Les Smith, a 12-year Ranger veteran, takes me in a pick-up truck to the edge of Pit Three.
Mining is done in layers, leaving the wall of the mine looking like a rice terrace built by giants; there is no rice, of course, but already grass and small bushes are colonizing the oldest surfaces near the top.
At the top of the pit, full trucks drive under a discriminator--a gantry carrying detectors which pick up radioactivity from the ore and determine the concentration of uranium--the grade--in that particular load.
This is important, because the processing plant operates most efficiently when fed on a steady diet of 0.3% ore; so batches of different grades are mixed in order to keep the input at that consistent level.

Global Trade
Whatever the record, Ranger will be gone within a decade, the economic portion of the deposit exhausted.
Under its agreement, ERA must return the site to its original pristine condition, and is in discussions about exactly what that means and how to achieve it.
Another economically viable ore body, Jabiluka, lies nearby, but the traditional owners vehemently oppose mining there.
Ranger’s closure may mark the end of uranium mining in the Northern Territory.
As we drive back to the capital, Darwin--the only sizeable population centre in the far north--it strikes me that the firm’s dilemma is a microcosm of the global uranium situation.
There is a constituency within Australia which would like to see all its uranium mines close.
For China and India it is a key component of their drive for plentiful energy to fuel their economic growth, the Bush administration is squarely behind plans to build new reactors, and some European countries are committed to the technology.
Demand begets supply. If Australia did close operations, production would simply expand elsewhere. Niger, perhaps?

Gas and coal may become the main energy sources in Indonesia in place of fuel oil the consumption of which accounted for 63 percent, a spokesman said.
Assistant for natural gas affairs to the deputy for mineral and forest energy resources coordination to the coordinating minister for the economy Ellyza Mankudu said here on Tuesday, coal consumption reached only eight percent of the country`s total fuel consumption.
In addition, natural gas consumption reached 17 percent, LPG two percent and electricity 10 percent, she said.
The government, under presidential decree no.5/2006 on national energy, has been trying to increase the share of coal to 35 percent (including liquefied coal two percent) by 2025, Ellyza said, anatara.co.id said.
The use of gas is expected to reach 30 percent, geothermal energy five percent, bio fuel five percent, and renewable energy five percent. Fuel oil consumption is expected to decline by 20 percent, and renewable energy included nuclear energy.
“In the short run, we have yet to include alternative energy in our program,“ she cited.
Elliza said, geothermal energy is a very potential source of energy, with its reserves in 2005 estimated at 108,527.34 BSCF, while consumption reached only 37,048.07 BSCF.
The natural gas producing provinces in the country include Nanggroe Aceh Darussalam (NAD), Jambi, Riau, South Sumatra, Lampung, Bangka Belitung, West Java, East Java, East Kalimantan, South Sulawesi, Central Sulawesi, Papua and Natuna island.
Meanwhile Indonesia`s natural gas export contract until 2032 reached 25,875 BSCF, with the export to Japan (1994-2015) totaling 9,127 BSCF, South Korea (1988-2025) 6,496 BSCF, Taiwan (1990-2017) 3,450 BSCF, China (2007-2032) 3,095 BSCF and to the United States (2007-2026) 3,988 BSCF.
Elliza said the government has designed a grand scheme on transmission network and national natural gas distribution (RIJTDGBN) in a bid to support the use of natural gas as source of energy.