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Tag Archives: floating wind

Can tidal power match wind costs?

By Dave Elliott

Wind power has developed quite rapidly around the world, heading for 500GW soon, with costs falling. On-shore wind is now one of the cheapest renewables. The UK has nearly 10GW on-shore and over 5GW offshore, with the latter expanding and new technology emerging – floating wind turbines.  However tidal power, although mostly at a much earlier stage in its evolution, is making a bid to compete, at least in the medium to long term. Although the Swansea tidal lagoon project will generate at a somewhat higher cost than offshore wind power, and certainly much higher than on-shore wind, it’s claimed that subsequent lagoons should be much cheaper, and tidal stream turbine developers are also confident about price reductions. Will tidal power really get cheap? That may depend on how these technologies get supported in the near future.

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EU Renewables round up

By Dave Elliott

Renewables are roaring ahead in Europe, with wind at over 140GW and PV surpassing 100GW. There have been some spectacular successes, with renewables briefly supplying 87% of German electricity at one point, and Portugal achieving similarly high contributions-something that’s a regular occurrence in Denmark. But progress may soon be slowed as  economic pressures mount and political reaction sets in with support schemes being withdrawn or constrained. For example, in Germany it’s all change as the government revises the Energiewende energy law with a slow down for wind and solar expansion, via annual capacity caps and reduced support levels. Portugal has also started to phase out its support for renewables, although not quite so aggressively as happened in Spain, or, for that matter, the UK. (more…)

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Offshore wind – will the US catch up?

By Dave Elliott

It has been striking how much more enthusiastic the EU, and the UK especially, has been on offshore wind compared with the US. The EU will soon have nearly 11GW installed, compared to zero so far in the US. Part of the reason for the difference has been that, unlike the US, there are shallow waters off the UK and some other parts of the EU, which enabled earlier easier projects, with piles driven into the sea-bed for supporting towers – nursery slopes, in effect. It wasn’t until new “floating” wind technology emerged that deep-water sites further offshore became viable. Floating jacket leg and spar buoy systems are being tested off the EU coast and the US and Japan are also now in the race, in the later case as part of the response to the Fukushima nuclear disaster, with a 2MW unit installed off Fukushima and 7MW floating devices now under test.
http://www.offshorewind.biz/2015/03/23/floaters-game-changers-for-offshore-wind/

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Green power in Asia – Part 2

By Dave Elliott

In my last post I looked at developments in China and India, where renewables have been playing key and increasing roles, with China clearly in the lead. By contrast, until recently, in Japan renewables had been given a low priority, but following the Fukushima nuclear disaster in 2011, Japan is now pushing ahead with some ambitious offshore wind projects, 1.45GW in all, using floating wind turbines, and a large solar PV programme, helped by lucrative Feed In Tariff subsidies. (more…)

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Green energy transformations

By Dave Elliott

The International Energy Agency (IEA) has released a new report “the Power of Transformation”, which concludes that the integration of large amounts of renewable energy can be achieved by any country at only a small increase on whole system costs, compared with the current fossil-fuel-heavy electricity systems. The IEA used present-day costs for solar PV and wind, which are likely to continue to fall, with wind and PV being set to provide the bulk of the generating capacity in transformed electricity systems. (more…)

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PV solar versus wind

By Dave Elliott

With costs falling rapidly, PV solar is moving ahead fast and some see it as likely to become a major renewable source in the future, if not the dominant one. The World Energy Council notes that in its new Symphony global energy scenario, “by 2050, globally, almost as much electricity is produced from solar PV as from coal,” and Shell’s recent “Oceans” scenario saw solar as being the largest single energy source globally by 2060. (more…)

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Undersea energy storage

By Dave Elliott

In my previous post, I looked at airborne wind power devices, which some see as a big new energy option. One major attraction is that tapping the high speed jet streams offers access to a much more continuous and reliable energy flow than using surface level winds. It means that the problems of intermittency can be resolved without having to resort to energy storage or complex grid balancing systems. But if ‘flying wind turbines’ sound too much like ‘Blue Sky’ thinking, then, coming down to earth, or rather under the sea, there are some new large-scale storage ideas, although they too are quite exotic. They involve giant underwater compressed air storage systems.

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Japan-progress on new energy

By Dave Elliott

The interim energy policy  outline that emerged in 2012 after the Fukushima nuclear disaster envisaged getting between 25% and 35% of Japans electricity from renewables by 2030, with wind and solar playing major roles.  A new fuller plan is expected soon, but in the meantime progress is being made with renewables, with the Japan Renewable Renewable Energy Foundation claiming that ‘Japan will be able to increase the electricity from renewables to at least 20% of its total consumption by FY2020 without putting an undue burden on corporations or on households’.  (more…)

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Offshore wind goes deep

For moment the EU leads the offshore wind field, with nearly 3GW in place, 1.3GW off the UK coast. The world’s largest offshore wind farm is currently the UK’s 300MW array at Thanet, in the North Sea. But the 500MW Greater Gabard project 23km off Suffolk is coming along and the 1GW London Array in the outer Thames estuary will top that, and many more are planned off the UK and also elsewhere, for example France is now looking for 30 sites for 3GW of offshore wind and wants 6GW by 2020. Overall, nearly 20GW has now been consented in EU waters. The longer term EU potential is put at maybe 150 GW, or much more, given newly emerging deep-water technology, allowing for location much further out in the North Sea and elsewhere, for example, off the coast of France, Spain and Portugal.

Although some projects are now emerging off New England, the US has been slow to develop offshore wind projects, in part since, unlike the UK and some other EU countries, it doesn’t have shallow water off its (east) coast. But deep-water technology solves that problem and, as in the EU, opens up a very large resource.

Deepwater Wind, a company based in Providence, Rhode Island, has drawn up plans for what could be the largest wind farm in U.S. waters – a 1GW Deepwater Wind Energy Center with 200 turbines off New England, which would cost $4–5bn. It would use 5MW turbines mounted on four legged platforms 18 to 27 miles off the Rhode Island coast at a depth of 52 meters: more than twice that of conventional steel ‘monopole’ wind turbine platforms.

As water depth increases, the diameter of monopoles must increase exponentially, making them uneconomical in water deeper than about 20 meters. By using a four-legged design, the company says they will be able to work in depths that were previously prohibitively expensive. And being far out to sea there should be fewer problems with objections over visual intrusion- a major issue so far in New England. More: www.dwwind.com

The basic deep-water technology, involving structures with multiple legs, was originally developed for oil and gas platforms and a version has already been used for some deep-water offshore wind turbines in the EU e.g. the Beatrice 2 x 5MW turbine project off Scotland. So-called ‘tension leg’ technology, with typically four semi-submersible piles tethered to the sea-bed, has been used. The 2.3 MW Dutch Blue H turbine, tested off Italy, used this concept. And in Portugal, EDP is developing a 2 MW WindFloat with three legs, while in France Nénuphar, Technip, and EDF are developing a novel Vertiwind device, with vertical axis wind turbine mounted on three legs. After work on a prototype, they hope to test a full scale 2MW device at sea in 2013.

If you want to go even further out and into deeper water then you need fully floating systems, like Norways Sway and HyWind, which, it’s claimed, can operate in depths of between 120 and 700 metres.
See my earlier blog.

Sway is about to start testing a scale prototype of its proposed 5MW floating turbine off the coast of Norway at site near Hordaland. The Sway turbine can tilt by 5–8 degrees from the vertical.

Although, a 2.3 MW version of HyWind has already been tested,10km off Norway, in general fully floating device technology is relatively undeveloped. But hopefully not for long. In addition to the work mentioned above, 19 partners from 8 EU countries, under the direction of the Fraunhofer IWES, have entered the conception phase for HiPRwind, the largest publicly funded research project for the development of enabling technology for deep-water offshore wind, with €11 m contributed to the €20 m 5-year project by the European Commission.

That’s in parallel with the EU’s £3m DeepWind Vertical axis Darrieus (‘egg beater’) type floating 10MW wind turbine project led by RISO in Denmark, Spain’s 50MW floating wind project 30km offshore in depths up to 100m, and the UK’s novel V-shaped vertical axis 10MWAerogenator X, developed out of the ETI’s Nova project.

China is also developing offshore wind technology. Its first offshore wind farm, a 102 MW array near Shanghai, is being followed by others Construction of a 1GW offshore wind farm in Bohai Bay, around three hours from Beijing, is expected to be complete by 2020. The Government has invested €1.6bn in the project, which is being managed by the state-owned China National Offshore Oil Corporation.

However, they are not currently looking far out to sea. As I reported in a previous Blog, they are looking at what they see as less risky and more commercially viable near-shore options: http://environmentalresearchweb.org/blog/2010/12/offshore-wind-costs.html.

In particular, with a potential 100 to 200GW being available in extensive tidal flats, the emphasis in China in the short term is on intertidal projects. There should be at least 10GW of installation by 2020 in Jiangsu province. A 30MW pilot project is under construction there and a 300-MW may follow, using 3.6MW turbines and a novel five pile support structure to cope with the tidal flat’s muddy seafloors and shifting sandbars.

www.technologyreview.com/energy/24978/?mod=related

It’s hard to know if deep-sea wind will prosper. If they can be developed successfully, floating wind turbines can be towed out to be located on station, and so can avoid some of the large deployment costs associated with drilling piles into the sea bed, and they can also be brought back to harbour for maintenance, avoiding the difficulty and cost of getting access at sea. But there are significant extra costs with longer undersea grid links. However, if and when a full North sea supergrid network is established, then some of these costs would be shared with other projects, and the system as a whole would earn more income by being able to transfer power between the UK and the other EU countries involved with the supergrid: see http://environmentalresearchweb.org/blog/2010/12/the-north-sea-supergrid.html.

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