Proposed giant tidal plant for mainland China is far-off dream

Dutch consortium's proposed giant tidal power project has attracted interest and investment from mainland firms, but experts are sceptical

PUBLISHED : Monday, 21 July, 2014, 3:18am
UPDATED : Monday, 21 July, 2014, 3:18am

A tidal power project proposed by a consortium of Dutch engineering firms for mainland China aims to rival the hydro project in the Three Gorges Dam but has a long way to go to prove its feasibility, much less lure would-be investors to make it a reality.

But the fact that it has attracted a commitment from mainland research institutes and power firms to co-invest millions of US dollars to conduct a detailed feasibility study says a lot about the mainland's desire to enhance energy security by tapping foreign technology, especially one with the potential to harness clean renewable energy to help fight air pollution shrouding major cities such as Beijing.

"Mass commercialisation of tidal power is very far away, maybe it will happen by 2050," said Lin Boqiang of the Xiamen University Centre for China Energy Economics Research. "Mainland research institutions may be looking into its feasibility out of our nation's desire to enhance energy security and tackle pollution, but the cost-competitiveness thus far is highly doubtful."

The mainland relies on pollution-prone fossil fuels, especially coal, for 90 per cent of its primary energy needs and Beijing wants the share of non-fossil fuels to rise to 15 per cent by 2020 through cleaner energy sources such as solar, wind, hydro and nuclear power.

Lin's scepticism contrasted sharply with the optimism of the Dutch consortium led by infrastructure design and construction firm Strukton, which said it hopes to complete by 2020 a US$40 billion tidal power project on the mainland which could generate 15,000 megawatts (MW) of electricity. It said that that would be enough power for more than 10 million homes.

By comparison, the Three Gorges project in Hubei province, the world's largest hydro power project, produces 22,400MW of power. It also took 20 years to build.

According to Rob Steijn, one of the inventors of the technology whose feasibility is being studied for the proposed project and director of the river, coast and sea department at Amsterdam-based infrastructure design and consulting firm Arcadis, the investment and capacity figures are the maximum they are looking for.

The eventual scale will depend on the proposed dam's design, which may stretch 60 to 100 kilometres along the Chinese coast.

If a 60km dam is built, the estimated cost is US$5 billion and it would generate 5,000MW of power. A T-shape 100km dam would allow up to 4,000 turbines to be installed, raising the capacity to 15,000MW, Steijn said.

After initial studies, a location between Xiamen in Fujian and Shantou in Guangdong is preferred over the entrance to the Bohai Sea in the north, he added. The engineers have to take into consideration tidal conditions, water depth, composition of the seabed and proximity to major ports.

A 15MW demonstration project in Ningde, Fujian, has been abandoned, although it could be re-activated depending on the outcome of the economic assessment, Steijn said.

The dam itself would be controversial due to its sheer length, given concerns it would disrupt shipping traffic and may be harmful to the environmental, although Steijn said ship-locks could be built for ships to pass.

Wang Haibo, a campaigner at environmental group Greenpeace's Beijing office, said construction of the proposed dam could upset marine ecology.

"It depends on the amount of silt dug up ... in nearby Xiamen, the water quality and marine ecosystem were damaged by dams built in the 1950s to link up a large island to the continent," he said. "The ancient amphioxus fish vanished from the area."

The environmental impact on protected Chinese white dolphins and egrets near Xiamen should also be studied, he added.

Industry watchers said the biggest hurdle facing the project is pure economics.

According to Steijn, the per MW construction cost for the project is estimated at around US$3 million, about 10 per cent higher than nuclear power projects being built on the mainland.

The tidal project's power generating cost is estimated at 10 to 15 US cents per kilowatt-hour (kWh), similar to the prices of 12 to 13.7 US cents per kWh at which subsidised offshore wind power is sold to the national grid. This means a greater subsidy will be needed for the tidal power project.

"The lack of any indicative subsidised power tariff for the proposed project means its economic viability is highly uncertain," said Pierre Lau, head of Asia utilities research at Citi. "With such a long dam needed to be built out into the sea, it may also face opposition from the shipping and fishing industries."

Gary Chiu, head of utilities and renewables research at Macquarie Securities, said the proposed project will need substantial government subsidies and policy support, which may take years.

By 2020, the generating costs and power tariffs of solar and wind farms are likely to be lower than today as technological advances continue, which will put more pressure on the tidal project's proponents to make it cost competitive.

Steijn said the Dutch consortium's technology will set it apart from those deployed in operating tidal energy projects elsewhere in the world.

He said its so-called dynamic tidal power (DTP) method of tapping hydro energy from daily tidal movements allows for much greater amounts of electricity to be generated.

"The DTP does not rely on high tide range or strong tidal flow to be economic, but rather it harnesses the energy potential from an enormous mass of water by capturing it through turbines under a very long dam," he said. Besides the mainland, he said the consortium is looking at Britain, nations around the North Sea and South Korea for possible commercialisation of the technology, although the Chinese engineers have been more proactive in studying it than their European counterparts.

The Rance tidal power station located on the estuary of the Rance River in Brittany, northwest France, is the world's second largest. It has been in operation since 1966 and taps the high tide range of the estuary.

With 24 turbines installed within a 750-metre barrage, the power station has a peak output capacity of 240MW that is only surpassed by the 254MW Sihwa Lake tidal power station in South Korea, completed in 2011.

Besides Strukton and Arcadis, the Dutch consortium also includes a turbine technology firm, an environmental consulting firm, an energy and maritime consultancy and two university research institutes.

The mainland group, led by the Hydropower and Water Resources Design General Institute, also includes the China Institute of Water Resources and Hydropower Research, the Second Institute of Oceanography of State Oceanic Administration, Nanjing Hydraulic Research Institute, Tsinghua University and Nanjing's Hohai University.

The corporate partners include China Three Gorges New Energy, as well as Hong Kong-listed wind power producers China Longyuan Power Group and Huaneng Renewables.

Steijn admitted the 2020 completion target is a very aggressive one, given the detailed economic, environment and social feasibility studies that will take up to two years to carry out as well as five years of construction time.

But he said the project's economics would improve if it is combined with projects such as offshore wind farms and deep sea ports and bridges that connect islands to the mainland so that the costs of infrastructure construction can be shared.

"Although I am not 100 per cent sure this project will be built, we should not let this technology go untested," Steijn said.