Authors: Henry Jeffrey, Mark Winskel, UK Energy Research Centre, Edinburgh University, UK
The challenge of Decarbonisation
This is a time of unprecedented attention on energy systems, certainly since the energy crisis of the 1970s. The broad acceptance that carbon dioxide (CO2) and other greenhouse gas (ghg) emissions are responsible for climate change has made decarbonisation of the economy an international policy priority (IPCC, 2007). Ambitious targets for economy-wide decarbonisation and low carbon technology deployment are being established across international policy, industry and research communities.
As part of this, the uK has set out a legally binding framework for decarbonisation from now to 2050. Following a recommendation by the uK Committee on Climate Change, the uK’s reduction target for all greenhouse gases (ghgs) is at least 80% below 1990 levels by 2050, with a recommended interim target of at least 34% by 2020 (CCC, 2008).1
These targets – some of the most ambitious legally binding levels of ghg reductions anywhere in the world – have been incorporated in the uK Climate Change Act (uK government, 2008a). Ocean energy is one of a number of emerging low carbon supply options that has the potential to help meet these targets.
Alongside major deployments of more mature low carbon supply technologies over the next decade, there is an opportunity for currently less mature emerging technologies, such as ocean energy, to contribute significantly to deeper decarbonisation over the medium to long term. Realising this potential will involve a complex interplay between technology development (and learning-by-research) and technology deployment (and learning-by-experience).
This paper begins by highlighting the specific technical challenges associated with the development of ocean energy. It will then use the UK as a case study to illustrate and discuss the potential deployment that could be achieved if these challenges are overcome and ocean energy competes in the overall energy mix. Building on the results from this case study the paper will culminate by laying out and summarizing the high level challenges associated with the large scale international deployment of ocean energy.
Ocean energy
Ocean energy (defined here as wave and tidal current technology2) is an emerging technology field with considerable promise. For example, it has been estimated that around 15-20% of uK electricity demand could be met by ocean energy (Carbon trust, 2006). This said, ocean energy innovation and industrial systems are at a relatively early stage of development as compared, for example, to wind power, and this is reflected in a wide variety of prototype device designs.
For example, there is still a wide range of engineering concepts for capturing wave energy, including oscillating water columns, overtopping devices, point absorbers, terminators, attenuators and flexible structures. tidal current energy exhibits less variety, with most prototype designs based on horizontal axis turbines, but vertical-axis rotors, reciprocating hydrofoils and Venturi-effect devices are also being developed. Two UK based companies (Pelamis Wave Power and MarineCurrent turbines) have recently installed full-scale devices that are representative of the sectors’ progress,Figure 1.
Figure 1: Full Scale Marine Energy Devices: Pelamis Wave Power (left) and Marine Current Turbines Seagen Device (right); (Sources: PWP, MCT)
In the wake of the 1970s energy crisis, a number of wave energy Research & development (R&d) programmes were established internationally, but – in contrast with wind energy – these efforts were not sustained, and there was very limited innovation in the ocean energy sector from the mid-1980s to late 1990s. Renewed policy interest (and public and private funding) over the last decade has provoked a resurgence in innovation activity, and the emergence of multiple device designs. These more recent efforts have been led initially by small and medium enterprises (SMEs) and university consortia, although large power companies and large scale public-private programmes are increasingly involved.
International interest and development activity has grown rapidly in recent years, and over a dozen countries now have specific support policies for the ocean energy sector. Additionally, full scale ocean energy test centres have been established in the uK and continental Europe, with new centres being built in the United States and Canada. Additionally, this international interest and growth has lead to the development of international standards specifically for ocean energy.
The nascent status of ocean energy technology creates considerable challenges for its development. In particular, there is a need to strike a balance between trials of the most advanced prototype devices, and also research on more radical but less developed designs and components. the Carbon trust have indicated long term learning rates for wave and tidal energy of up to 15% and 10% respectively, but also highlighted the importance of taking advantage of step change improvements (Carbon trust, 2006).
Research challenges and priorities
As indicated in the previous section, both wave and tidal current energy still face a number of significant technology challenges in order to reach fully commercial status. A representative, but by no means exhaustive, summary of the general challenges for the sector is provided below:
Case Study: potential Development and Deployment of ocean energy in the UK
This case study investigates the prospects for accelerated development of a range of ocean energy supply technologies, and the impact of this acceleration on the decarbonisation of the UK energy system. Technology acceleration is analysed firstly by devising detailed single technology scenario (ocean energy) of accelerated development, and then system-level modelling of the potential impacts of this acceleration on the UK energy system from now to 2050. The results of the case study highlight the potentially important role for ocean energy technology acceleration in the transition to a low carbon energy system in the UK, and also its wider international significance.
Input Assumptions
Given the leading position of the uK in the ocean energy sector, domestic innovation support policies are potentially able to influence the progression of the sector internationally over the short to medium term. Using plausible deployment figures for the period to 2015, and international learning rates and initial capital cost figures derived from the Carbon trust (Carbon trust, 2006), ‘accelerated’ learning curves for wave and tidal were produced. (note that this analysis isbased on the continuation and expansion of tariff and capital support mechanisms in the uK and elsewhereto support niche deployment and learning).
Fig 2: Indicated impact of ocean energy acceleration in the UK (2000‑2050) Fig 3: Indicated impact ocean energy in a UK aggregated scenario
Results: Single technology Scenario
In the single technology scenario (Figure 2 above), with ocean energy technologies accelerated alone (and all other technologies under non-accelerated ‘business as usual’ assumptions), technology acceleration makes a substantial difference to the deployment of ocean energy technology in the uK, with over 20gW ofinstalled capacity by 2050.
Results: Aggregated Scenario
In the aggregated scenario case, all low carbon energy supply technologies are accelerated in parallel and compete for market share. In this case ocean energy continues to make a significant contribution to the supply mix (see Figure 3, here ocean energy supplies almost 15% of all electricity generated in 2050, i.e.over 240PJ (67 tWh)).
Discussion of Results
These scenarios provide only possible illustrations of the future. In practice the feasibility of their implementation depends on many issues beyond the relative costs and performance of different supply technologies, such as raw material prices, supply chain capacities and investment risks. In addition, energy system change is also affected by patterns of energy demand, the networks used to transfer energy between production and consumption, and many other regulatory, organisational and political interests and pressures.
For this scenario to be realised, over the period to 2020 there is likely to be a progressive device design consensus, with a distinct group of wave and tidal designs becoming ‘industry standards’. Consolidation in the market place is also likely, with mergers and acquisitions allowing hybrids of the best technologies to emerge and reduce overall costs. up to and beyond 2020, it is conceivable that disruptive technologies, embodying novel approaches to energy extraction, will be introduced, allowing for accelerated cost reduction, although the timing of these breakthroughs is difficult to predict. UKERC’s Marine Energy technology Roadmap (UKERC, 2008a) details the technology and commercial challenges involved in establishing a deployment strategy for the ocean energy sector up to 2020.
Beyond 2030, it is implausible to speculate in any detail as to the future direction of the industry; however, given continued publicly and privately funded development programmes, and associated learning effects, device costs are likely to decrease, and performance increase. While an accelerated development trajectory for the ocean energy sector involves some degree of design consensus over the medium term, there is a danger that if this consensus is imposed too early it may lead to ‘lock-in’ around devices with less scope for development in the longer term.
Summary of International challenges
Realising ocean energy development scenarios will depend on a co-evolution of accelerated development and deployment, with ocean energy technologies benefiting from learning-by-experience associated with early deployments, in conjunction with learning-by research to enable step changes in technology performance and cost.
The significant levels of deployment indicated in the case study scenarios, when replicated internationally, are unlikely to be met with the existing international supply chain infrastructure, and will require considerable investment in specialised and dedicated installation equipment. Some of this investment is already underway: for example, some technology developers have already taken delivery of dedicated installation vessels. Additionally, technology acceleration will involve measures to address the generic technical challenges highlighted in the UKERC Marine technology Roadmap (Figure 4, below)
Figure 4: Generic Technical Challenges involved in Marine Energy
Technology Acceleration
A coherent and adaptive approach to policy, across international energy arenas, will be needed to providean appropriate combination of support mechanisms, and ensure effective distribution of investments as the sector matures.
Overall, in the short term, there will be considerable deployment challenges for the sector, with planning and legislation, human resource skills shortages, and availability of installation vessels all being significant hurdles. Despite a certain level of existing headroom, grid reinforcement will also be a significant challenge for many countries during this period.
In the medium term the challenges of planning and regulation should have been largely addressed. despite the capacity that will have been built up in the preceding period, skills shortages and availability of vessels will still be a challenge to the sector due to the ramp-up in build rate in this period. given the remote nature of many of the ocean energy resources, major grid reinforcements will be a major challenge during this period, with the need for an offshore grid highly likely. International initiatives, such as the “European Supergrid”, are already beginning to address this issue.
The long term appears less challenging for the sector, to the extent that many earlier limitations need to have already been managed (such as supply chain constraints, planning constraints and grid implications). However, additional capacity may be exploitable by this time, so that deployment may continue increasing beyond, for example that indicated in the uK casestudy, above. In addition, competition for resources from other energy and non-energy sectors could have significant impacts on their availability to the ocean energy sector across all time periods.
Conclusion
Ocean energy is an emerging technology field with considerable promise over the medium and longer term. The industry has just started demonstrating full-scale devices and device arrays. The nascent status of ocean energy technology creates considerable scope for accelerated development. In realising this potential, however, there is a need to allow for parallel progress in demonstration trials of the most advanced wave and tidal prototype devices, and also research on more radical but less developed designs and components.
The case study scenario described here indicates that technology acceleration has the potential to make a substantial difference to the deployment of ocean energy technology in the uK, with initial deployments starting soon after 2010, and rapid expansion after 2030. Under these accelerated development assumptions, ocean energy supplies almost 15% of all electricity generated by 2050, and additional exploitable resource may allow for further increases to this figure.
Accelerating ocean energy to achieve these deployment levels will require sustained support for its development over time. A coherent and adaptive approach to policy, in the uK and internationally, will be needed to ensure effective investments as the sector matures. In particular, there is a need to strike an effective balance between technology-push and marketpull mechanisms, to allow for design consensus, but at the same time avoiding ‘lock-out’ of breakthrough technologies which may allow for step-change improvements. there are also considerable associated investment needs in supply chains, installation capacity, and electricity networks. With these in place, the work here indicates that ocean energy can become a significant contributor to low carbon energy supply systems in the UK and beyond.
Acknowledgements
The research for this paper and case study was conducted under the auspices of the UK Energy Research Centre (UKERC) which is funded by the natural Environment Research Council, the Engineering and Physical Sciences Research Council and the Economic and Social Research Council.
More specifically, the research reported here has been supported by energy systems analysis using the UK MARKAl elastic demand (MEd) model. The operation of the UK MARKAl MEd model is detailed in the report (Anandarajah et al., 2008).
References
Anandarajah, G.N. Strachan, P. Ekins, R. Kannan, n. hughes(2008) Pathways to a Low Carbon Economy: Energy SystemsModelling. UKERC.
Carbon trust (2006) Future Marine Energy: Results of the Marine Energy Challenge: Cost competitiveness and growth of wave and tidal stream energy. London, Carbon trust.
CCC (Committee on Climate Change) (2008) building a lowcarbon economy – the uK’s contribution to tackling climate change. tSO, London.
IPCC (Intergovernmental Panel on Climate Change) (2007). The Fourth Assessment Report: Climate Change 2007. IPCC, Geneva.
Jeffrey H. (2008) An Overview of the issues associated with the future costing of marine energy and the application of learning rate theory, ICOE, Brest 2008.
UKERC (2008a) UKERC Marine (Wave and Tidal Current)Renewable Energy Technology Roadmap: Summary Report.UKERC, Edinburgh.
Winskel, M. (2007) Renewable Energy Innovation: Collaborative Learning and Intellectual Property. International Journal of global Energy Issues, Vol. 27, no. 4,472-491.
1. The UK Climate Change Committee recommended that the decarbonisation targets be applied to all greenhouse gases, and not just CO2emissions. This was subsequently accepted in the uK Climate Change Act (CCC, 2008; UK government, 2008). non– CO2emissions accounted for 15% of total ghg emissions in 2006 (CCC, 2008). The modelling scenarios presented in this report only consider CO2 emissions.
2.Tidal barrages, lagoons or ocean thermal circulation technologies are notaddressed here.
