PelaStar Cost of Energy: A cost study of the PelaStar floating foundation system in UK waters

Abstract:

Studies carried out by the Energy Technologies Institute (ETI) and by the European Wind Energy Association have shown that floating offshore wind, close to shore and in water depths of between 60 to 100m, could significantly reduce the cost of offshore wind energy. Further analysis by ETI indicated that the tension-leg platform (TLP) floating concept has the best potential for reducing cost, and they commissioned the Offshore Wind Floating Platform Demonstration Project FEED Study to better understand and determine the levelised cost of energy (LCOE) associated with the TLP concept, particularly as applied in United Kingdom waters.

Earlier ETI studies showed that floating foundations could be very attractive, by allowing the UK to access higher wind sites that are reasonably close to shore. Our analysis suggests that floating offshore wind has the medium to long term potential to deliver attractive energy costs. The Glosten Associates, a US-based navel architecture and marine engineering firm have designed a tension leg platform (TLP) floating system demonstrator through a Front End Engineering Design (FEED) Study.

The selected design was the PelaStar TLP developed by Glosten, Inc., of Seattle, Washington, USA. PelaStar is a deep-water, floating foundation structure system for offshore wind turbines. This report presents a comprehensive analysis of the levelised cost ofenergy for PelaStar in United Kingdom (UK) waters.The results presented in this report show that the PelaStar TLP, supporting a 6 MW offshore wind turbine generator, can achieve an LCOE of £106/MWh in average UK conditions, and a LCOE as low as £97/MWh at sites with superior wind conditions.

Key findings:

• A LCOE in 2020 in the range of £100/MWhto £110/MWh can be achieved across most of site conditions encountered in commercially exploitable UK waters.
• Cost-effective access to high-wind-speed sites is enabled, thereby driving down the levelised cost of energy below £100/MWh at these sites.
• High-wind-speed sites yield the lowest LCOE, even after the increased capital expenditure (CAPEX) associated with accessing such sites is considered.
• The LCOE shows little variation across the range of conditions encountered in commercially exploitable UK waters.
• This LCOE is forecast to drop by over half by 2050 in today’s currency, due to expected learning curves and economies of scale achieved in the PelaStar system when paired with larger (10 MW) wind turbines.

Publication Year:

2015

Publisher:

ETI

DOI:

https://doi.org/10.5286/ukerc.edc.000613

Author(s):

Hurley, W.L. and Nortstrom, C.J.