Full LCA of Wave Energy

Conversion

R Camilla Thomson, G P Harrison and J P Chick

Institute for Energy Systems, School of Engineering, University of Edinburgh

26th February 2016

Images from www.pelamiswave.com and www.aquamarinepower.com

Introduction

• Very few Life Cycle Assessments for wave energy conversion

• Generic methodological framework for LCA introduces

considerable scope for variation in results

• Existing focus on carbon and energy

• More complete LCA of Pelamis and Oyster, considering a

broader range of environmental impacts

NREL data taken from the LCA Harmonization Project, http://en.openei.org/apps/LCA/

Pelamis P1

• Semi-submerged, snake-like offshore wave energy converter

made of a series of articulating buoyant steel cylinders.

• The passage of the wave front causes the joints between the

cylinders to flex, moving hydraulic rams that pump high-

pressure oil through a system to drive induction generators.

• Parker et al. published a carbon and energy audit in 2007 [2].

• Full LCA published in 2014 [5].

Pictures and graphic adapted from www.pelamiswave.com.

Oyster 1

• Buoyant hinged steel flap fixed to the sea bed.

• Wave surges induce oscillations of the flap that are resisted by

hydraulic rams; these pump water through a pipe to shore,

where a Pelton turbine and generator convert the energy to

electricity.

• Walker and Howell published a carbon and energy audit in 2011

[3].

• Full LCA yet to be published.

Image from www.aquamarinepower.com.

The Analysis

• Cradle-to-grave

• Inventory of resource use and

emissions at all stages:

– Materials & Manufacture

– Assembly & Installation

– Operations & Maintenance

– Decommissioning & Disposal

• Classify and characterise

results to determine impact

potentials

Pelamis Results

• Greatest impacts from

manufacturing and

maintenance stages

– Steel production

– Sea vessel operations

• Energy intensity

– 469 kJ/kWh

– 31 months payback

• Global warming potential

– 30 gCO2e/kWh

– 15 months payback

Oyster Results

• Greatest impacts from

materials

– Steel production

– Seabed fixings

• Energy intensity

– 889 kJ/kWh

– 59 months payback

• Global warming potential

– 79 gCO2e/kWh

– 41 months payback

Image courtesy of Pelamis Wave Power Ltd.

Sensitivity Analysis

Comparison

Conclusions

• Carbon and energy

intensities compare

favourably.

• Greatest impacts due to

• Considerable uncertainty

is introduced by LCA

methodology:

– Recycling allocation

method: 34%

– Inclusion of all GHGs:

11%

Pictures from www.pelamiswave.com and www.aquamarinepower.com

Dr R Camilla Thomson

c.thomson@ed.ac.uk

References

1. Warner, E., G. Heath, and P. O'Donoughue, Harmonization of Energy

Generation life Cycle Assessments (LCA). 2010, NREL: Golden, Colorado.

2. Parker, R.P.M., G.P. Harrison, and J.P. Chick, Energy and carbon audit of an

offshore wave energy converter. Proc. IMechE Part A: J. Power and Energy,

2007. 221(A8): p. 1119-1130.

3. Walker, S. and R. Howell, Life cycle comparison of a wave and tidal energy

device, Proc IMechE Part M: J. Maritime Environment, 2011, 225:p. 325-337.

4. Soerensen, H. C. And S. Naef, 2008. Report on technical specification of

reference technologies (wave and tidal power plant), New Energy Externalities

Developments for Sustainability, SPOK, p59.

5. Thomson, R.C., Carbon and Energy Payback of Variable Renewable

Generation, PhD Thesis School of Engineering, University of Edinburgh,

Edinburgh, 2014.

Images from