More stable, more sustainable - The UK power system benefits from deployments of wave and tidal stream generation

More stable, more sustainable - The UK power system benefits from deployments of wave and tidal stream generation

By Shona Pennock, The University of Edinburgh

System benefits can be quantified from including wave and tidal stream deployments in high renewable future energy scenarios. These benefits are the result of resource offsetting between marine renewables and more established renewables such as wind and solar.

Introduction

Following on from the previous two blogs, which showed potential European deployment trajectories for marine energy and the cost reduction trajectory which could be achieved from tidal stream deployments, this final instalment quantifies the potential power system benefits gained through the deployment of marine energy technologies.

These system benefits are primarily due to the temporal and spatial offsetting of wave and tidal resources with other, more established variable renewables, such as wind and solar. Wave and tidal generation can be available at times of low wind or solar resource, helping to balance the overall renewable power profile. It has been found that a more diverse generation mix including marine energy is consistently more available and better able to meet demand than a renewable generation mix consisting of only wind and solar.

To investigate and quantify these system benefits, a case study has been established which focuses on a 2050 net-zero compliant scenario for the power system of Great Britain. System benefits from marine energy are quantified over a range of metrics: increased renewable dispatch, decreased peaking generation and fossil fuel dispatch, decreased storage requirements and decreased dispatch costs.

This case study is founded on deployment scenarios, where cost, performance, and systemic conditions are defined by the 2030 levelised cost of energy (LCOE) targets in the Strategic Energy Technology Plan for Ocean Energy. These targets of €100/MWh for tidal stream and €150/MWh for wave are ambitious, but fall within the uncertainty ranges presented within the DMEC (Dutch Marine Energy Centre) and Offshore Renewable Energy Catapult studies presented by Simon Johannes Stark and Ciaran Frost in the previous blogs. Deployment modelling obtained from the Energy Systems Catapult (ESC) forms the basis of the GB 2050 future energy scenarios used in this analysis. Scenarios both with and without marine energy are included, in order to directly compare the impact of including marine energy within the future generation mix.

The resultant deployment scenarios for 2050 have then been modelled using the EVOLVE Great Britain economic dispatch model. This model computes the least-cost supply-demand balance over a full year of electricity dispatch, at an hourly timescale, representing perfectly competitive wholesale market operation.

The results

Results from this work can be summarised as:

• Energy planning modelling by ESC projects 6.4GW of wave and 6.2GW of tidal stream deployments in GB by 2050, if the SET Plan targets are reached by 2030.
• Previous work has shown that the resultant value to the UK economy from these deployments would be up to £8.9bn Gross Value Added (GVA).
• This study shows that the potential power system benefits of this 12.6GW deployment of marine energy would be up to £1.03bn reduction in dispatch costs per annum.
• This cost reduction comes from a higher dispatch of renewable energy – by up to 27 TWh (+6%), and thus a lower requirement for expensive peaking generation – by as much as 24 TWh (-16%) when wave and tidal generation are part of the electricity mix, compared with a scenario without marine energy generation.

Additionally, the scenario which includes marine energy demonstrates a higher ability to meet domestic (GB) demand with domestic generation, as it requires 5 TWh less (-65%) battery use and 3 GWh less (-6%) energy imports via interconnectors.

• Several sensitivity analyses have also been performed on the modelling input data, and it has been found that the general trend in results is consistent between every sensitivity scenario, that is: a higher penetration of marine energy results in lower dispatch costs, higher renewable dispatch, lower peaking generation and flexibility requirements.

Concluding thoughts

This analysis is particularly meaningful as there are very few studies that quantify the system benefits associated with including marine energy within country-scale power systems. These results will be of interest to various stakeholders across the sector: technology and project developers, academic and industrial researchers, and grid operators and policy makers looking to develop future decarbonised systems whilst maintaining security of supply. 

It should be noted that these system benefits to the GB power system are only achievable if focused investment in marine energy technologies enables a reduction in LCOE and continuous successive deployments. The potential for long-term cost reduction and scale-up of wave and tidal stream technologies in Europe has been highlighted by Simon and Ciaran in the previous two blogs, and while it is clear that marine energy has a huge potential in Europe, ongoing policy support is required for these technologies to continue to progress.

Why marine energy will be a key contributor to European energy security

While security of energy supply, cost of energy and the growth of new sectors and industries are all important concerns in Europe this blog series has shown that marine energy is a real solution to all of these:

• By being decoupled from other renewable energy sources, marine energy can increase the use of renewable energy in the electricity system. 
• By scaling up deployments, costs will decrease in the coming years. 
• Growth of other offshore renewable sectors shows that marine energy can be a key contributor in the coming years.

With all of this, marine energy poses a great opportunity for Europe, which is still leading in the development of this technology. With the support of the energy industry and national governments it will become a key contributor to a decarbonised energy system. 

This blog is based on a recently published study by Shona Pennock and Henry Jeffrey at the Policy and Innovation Group, The University of Edinburgh: “What are the UK power system benefits from deployments of wave and tidal stream generation?”. This study was funded through the Supergen Offshore Renewable Energy Hub. To get a copy of this report click here.

Marine Energy series: 'Three reasons why marine energy will be a key contributor to European energy security', by Ocean Energy Europe, Offshore Renewable Energy Catapult, The University of Edinburgh and DMEC (Dutch Marine Energy Centre)