Engineering news
The Energy Technologies Institute has released details of a new study that claims a design of floating wind turbine could one day cut offshore wind energy costs by £65 per MWh.
Loughborough's ETI said an engineering design study by Seattle-based naval architects The Glosten Associates, using its tension leg floating platform (TLP) for offshore wind demonstrator, has shown that UK offshore wind energy costs could fall to below £85/MWh by the mid-2020s. The design could potentially be deployed en masse across UK waters to slash the cost of offshore wind energy, the ETI said.
Offshore wind currently costs about £149 per MWh of electricity it produces. This compares to about £90 per MWh to generate electricity from onshore wind. The government aims to reduce the costs of offshore wind to £100 per MWh by 2020.
The TLP works in water depths of 55 metres up to several hundred metres. It would be deployed in areas offshore within 70 kilometres of a major grid connection so that DC connections and offshore maintenance teams are avoided, which increase costs, said Andrew Scott, who is in charge of the offshore wind programme at the institute. “You want to avoid an offshore oil and gas-style maintenance regime,” he told PE.
Tension leg platforms are said to be more stable than some competing floating platform designs. They rely on being submerged below their natural buoyancy by some eight to 10 metres and tethered to the seabed. The tension between their submersion and the upward force of the water produces their stability. They also use much less steel than some semi-submersible solutions, Scott said. “The materials for a semi-submersible platform for a 6MW turbine is in the order of 6,000 tonnes of steel. With a TLP for a 6MW turbine it is about 1,100 tonnes of steel – you are talking a big difference.” The idea is that the design would be mass-produced to exploit economies of scale. The ETI is now looking at the possibility of a 6MW demonstrator but Scott said finding backers would be challenging. “It is difficult when there is not an obvious return on a demonstrator.” He said that Scotland had an “enhanced” renewables obligation certificate (ROC) for offshore floating turbines and therefore was the most promising UK market. Scott said: “It's probably commercially more attractive to demonstrate floating offshore wind in Scotland than elsewhere in the UK.”
Meanwhile, a project to reduce the cost and time it takes to establish offshore wind farms is to benefit from £2.2 million of government funding. Nine developers with around 70% of the UK's offshore energy capacity will work to share knowledge and best practice in areas such as building foundations, maintenance of turbines, electrical systems and cable installation.
The Carbon Trust's Offshore Wind Accelerator (OWA) programme will receive £200,000 in the 2014/15 financial year and £2,000,000 in 2015/16. The announcement was made by First Minister Alex Salmond and will also see developers work on “the commercialisation of floating offshore wind turbines for Scottish waters”.
The aim is to reduce the time it takes to finish developments by around 10% and ultimately bring about reduced financial costs.
Developments with the "most significant savings potential" will be prioritised by the OWA project.
Salmond said: “Scotland is admired around the world for our work in renewable energy and in 2013 we set a new record for renewables generation, emphasising our commitment.
“That progress has accelerated into 2014 with new record levels of renewables generation in the first months of this year – up 56% over the year to the first quarter of 2014.
“The Scottish government's target is to generate the equivalent of 100% of Scotland's gross annual electricity consumption from renewable sources by 2020, as part of a wider, balanced, energy mix, and we are already nearly half way there.
“Renewable energy is extremely valuable to Scotland's economy, to reducing our carbon emissions and in providing low carbon energy supplies as well as jobs and long term investment.”
The developers working in the project include E.ON, RWE, ScottishPower Renewables, SSE Renewables and Vattenfall.