The cost of tidal power

A tidal power plant is perhaps the most capital-intensive type of power station yet envisaged. It involves building a low-head hydropower scheme in the tidal reaches of an estuary, an environment where construction is, at best, difficult. Construction schedules are long so lengthy up-front loans are required, with a considerable gap between granting of the loan and income from the plant.

There is so little experience with this type of project that no useful conclusions can be drawn from experience. However several projects have been examined and costed, particularly in the UK and more recently in Australia. These provide some economic guidance.

The best site in England is the estuary of the River Severn. It has been extensively studied. The design favoured by the Severn Barrage Development Project in a 1989 report involved construction a power station with an installed generating capacity of 8640 MW. This was expected to take 10 years to build at a cost of around $17 billion at 1994 prices, a unit cost of $1970/kW.

A smaller project, on the River Mersey in northwest England, has also been examined in some detail. A plant with a proposed generating capacity of 700 MW was expected to cost around $1.5 billion to build, at 1994 prices, a unit cost of $2150/kW. This scheme would take 5 years to complete.

Capital costs for these two schemes are in line with the cost of similarly sized traditional hydropower projects. But tidal power has two special features which must also be taken into account. First, the load factor is low. A plant operating on the ebb tide will only generate power for half the time. Typical load factors for tidal power plants are around 23%. Efficiency can be improved slightly by pumping water from the sea across the barrage at high water to increase the head of water. However this involves additional capital expense for pump turbines.

The second special feature associated with tidal power relates to the time at which power is generated. Generation is restricted to the period between high tide and low tide. This period will occur at a different time each day.

As a consequence, the primary role of a tidal power plant is likely to be to replace generation from conventional fossil-fuelled power stations. When a tidal plant is generating, fossil fuel consumption can be cut back. When it stops generating the conventional plants must be brought back into service.

There is a way of re-timing the output of a tidal plant, but that involves building an allied electricity storage station. This would permit tidal power to be delivered either at a steady rate, or at times when the plant is not actually generating. However the addition of a storage facility pushes up the cost of the tidal project.

These features mean that the electricity generated from a tidal power station tends to be expensive. UK estimates, based on figures published by the Energy Technology Support Unit, suggest a generation cost of around $0.1/kWh assuming a discount rate for loan repayment of 8%. The cost of electricity roughly doubles if the discount rate is 15%.

In Australia, the government of Western Australia commissioned a report into a tidal power plant at Derby.1 The report found that the most cost-effective option was a 5 MW tidal plant which would cost A$34 million. The cost of power would be A$0.41/kWh. In this case the plant was intended to replace power generated using diesel engines, which is an expensive source. However even with a renewable energy credit, the project was judged too expensive.

As both the UK and Australian examples indicate, on a purely economic basis tidal power looks uncompetitive today. But other criteria should be taken into account when determining the true cost of a tidal power plant. The lifetime of a tidal barrage is probably 120 years; and that is a conservative estimate. Turbines will probably need replacing after 30 or 40 years. Thus, once loans have been repaid, the plant will still have a long life during which it can be expected to generate cheap electric power.

Today, however, the capital intensity is crucial. And without some sort of government support or encouragement, tidal power does not look attractive. Private sector companies have been heavily involved in studies of tidal projects in the UK, but none has yet been tempted to commit itself to construction. The Derby project in Australia was also put forward by the private sector, but this was rejected by the state government in favour of fossil fuel power. While the Australian developers remain hopeful that they can develop a project elsewhere, the outlook for tidal power is generally poor. Changes in the financial and political climate may make tidal power look more attractive in the future. But for now most projects look set to remain paper studies.

Continue reading here: Storage technologies

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  • jasmine
    How d tidal generators work?
    4 months ago
  • michael
    What is the cost of one barrage in tidal energy?
    6 months ago
  • danait tesfalem
    Is tidal energy expensive to utilize?
    7 months ago
  • SEAN
    What did it cost to build the tidal turbine?
    8 months ago
  • fre-swera
    How to find the total cost of a tidal power plant?
    10 months ago
  • Haiduc Goold
    How much does a tidal energy plant cost in China?
    1 year ago
  • Mikolaj
    How ,uch would it cost to manufacture a device for tidal energy and transport the energy to Beijing?
    1 year ago
  • juuso
    How expensive is a tidal power plants cost?
    1 year ago
  • mewael
    How expensive is it to create tidal power?
    1 year ago
  • mitchell
    How long does it take to build tidal power?
    1 year ago
  • Heli
    How much land does it take for a tidal power plant?
    1 year ago
  • LUDOVICO
    What is the price of tidal energy machines?
    1 year ago
  • maria wadsworth
    What are the cost implications with tidal energy?
    2 years ago
  • amelia
    What is the cost and efficiency to produce tidal power energy?
    2 years ago
  • ursula
    How much do tidal turbines cost?
    2 years ago
  • furio
    What is the startup cost of tidal energy UK?
    2 years ago
  • meaza
    How much does tidal power energy cost?
    2 years ago
  • nicodemo
    What is the cost of wave power uk?
    2 years ago
  • TIMOTEA
    How much to start up a tidal wave?
    2 years ago
  • pasi
    How much does it cost to generate tidal power in kwhr?
    2 years ago
  • aatifa
    What is the cost of building a tidal barge?
    2 years ago
  • anna
    How much kilowatt do tidal energy ccost?
    2 years ago
  • jodie
    How much does the decommission of tidal energy cost?
    2 years ago
  • demi
    How long does it take for marine tidal power stations to pay off?
    2 years ago
  • edward
    Who much does it cost to build a tidal energy facility?
    2 years ago
  • pansy sackville
    How much do tidal power sources cost?
    2 years ago
  • hanno
    How long does it take to build a tidal station?
    2 years ago
  • fastolph
    What is needed to run a tidal power plant?
    2 years ago
  • belba brown
    How much does it cost to creat tidal energy?
    2 years ago
  • remo
    What are the costs involved in tidal power?
    2 years ago
  • pervinca oldbuck
    What is the cost of tidal power compared to other renewables?
    2 years ago
  • selamawit
    How do the set up costs of tidal power compared to the other resources?
    2 years ago
  • celedor
    How econimically efficient is tidal power?
    2 years ago
  • Peregrin
    How much does it cost to build tidal energy plant in canada?
    2 years ago
  • Nadia
    Who gets the capital cost on tidal barrages?
    2 years ago
  • goytiom
    What is the costs of hydroeletric, wave and tidal power?
    2 years ago
  • sara vanpelt
    Why does a tidal turbine cost so much?
    2 years ago
  • marivel
    What is the cost of construction for tidal generators?
    2 years ago
  • Grace
    How is tidal power generated?
    2 years ago
  • p monto
    How much does tidal energy cost to implement?
    2 years ago
  • isengrin
    What is the cost of construction for the energy of tidal?
    2 years ago
  • sebastian haapakoski
    How much will it cost to build a tidal power station?
    2 years ago
  • SONJA
    What is the cost of tidal power compared to the current cost of fossil fuels?
    2 years ago
  • leon krueger
    How much would building a tidal energy plant cost?
    2 years ago
  • fedele
    How many tubines average are in a tidal power plant?
    2 years ago
  • bisirat
    How much does tidal power cost to instal?
    2 years ago
  • isaia schiavone
    How much do tidal energy plants cost?
    2 years ago
  • lobelia
    How much does it cost to build a tidal barrage?
    2 years ago
  • Jamie Fall
    How much is a tidal turbine?
    2 years ago
  • Esa
    How much does a tidal power barrage cost?
    2 years ago
  • linda brown
    What were the discount rates tilda power?
    2 years ago
  • melissa
    What is the capital cost of building a tidal barrage?
    2 years ago
  • DUSTIN
    How efficient are tidal power plants?
    2 years ago
  • Brigitte
    How much does tidal plants cost to construct?
    2 years ago
  • atte
    What is the average cost for a tidal power plant?
    2 years ago
  • Vappu Hyv
    How much does it cost to set up tidal power generator?
    2 years ago
  • Jodie
    What are the generatung costs of tidal energy?
    2 years ago
  • frank
    What is the generating costs of tidal energy?
    2 years ago
  • jackson
    Is tidal energy in the uk cost effective?
    3 years ago
  • codi
    How to estimate operational cost of tidal plant?
    3 years ago
  • segan
    How much does it cost to shut down tidal power?
    3 years ago
  • anke eberhart
    How expensive is the technology needed for tidal power?
    3 years ago
  • Natasha
    How expensive is it to create a tidal plant?
    3 years ago
  • guendalina
    How much does it cost to bulid a tidal power plant?
    3 years ago
  • Birikti
    What is the cost of tidal waves for energy?
    3 years ago
  • melissa
    How is tidal power costs being handled?
    3 years ago
  • senait
    What is the cost and maintenance of.tidal.power.stations?
    3 years ago
  • ginevra esposito
    What is the cost of generation facilities for tidal energy?
    3 years ago
  • Aaron Munro
    How expensive is tidal power?
    3 years ago
  • armando
    Is tidal power cost effective?
    3 years ago