Technical Summary

Ocean Power

Project Drawdown defines ocean power as: wave energy converters and tidal systems for electricity generation. This solution replaces conventional electricity-generating technologies such as coal, oil, and natural gas power plants.

This assessment focuses on three types of marine renewables: wave energy converters, tidal stream, and tidal barrage, together called ocean power. Wave energy converters are devices which convert the kinetic motion of ocean waves into electricity. Tidal stream energy can be tapped by using devices which act as underwater wind turbines, converting the flow of tidal currents into electricity. Tidal plants are large, utility-scale systems which direct the flow of tides through turbines to generate electricity, akin to hydropower electricity generation.

Of the many types of renewable energy, wave and tidal energy is arguably the most predictable. While the resource is spread out globally, there are only a few locations where wave and tidal energy can be harnessed commercially. The technologies used to convert marine energy to electricity are quite different. Tidal plants, which are more akin to large hydro plants, have replacement timeframes on the order of 40 years or more. On the other hand, wave energy converters only last a couple of decades.

Methodology

This analysis models wave energy converters and tidal systems for electricity generation.

Total Addressable Market[1]

Two total addressable markets were developed for this sector solutions, supported on lower and higher climate emissions mitigation targets linked to different levels of electricity demand and renewable energy sources integration. The total addressable market for wave and tidal is based on projected global electricity generation in terawatt-hours from 2020-2050, with current adoption[2] being: 1.06 terawatt-hours, representing only 0.004 percent of global electricity generated.

Adoption Scenarios[3]

Impacts of increased adoption of ocean power from 2020-2050 were generated based on two growth scenarios, which were assessed in comparison to a Reference Scenario where the solution’s market share was fixed at the current levels. For ocean power solution, the scenarios developed were:

  • Scenario 1: This scenario is based on the average of yearly ambitious adoption pathways from recent long-term projection estimates from IEA (2017) Energy Technology Perspectives 2DS and B2DS scenarios; IEA (2018) World Energy Outlook SDS; and Energy [R]evolution Scenario from Greenpeace (2015); considering a medium growth trajectory. As a result, this scenario projects that ocean power could capture 0.86% of the generation mix in 2050 with close to 400 TWh of electricity generated.
  • Scenario 2: This scenario is derived from the same sources of the Scenario 1, though considering a high growth trajectory, resulting in just over 520 TWh of electricity generated in 2050.

Financial Model

Based on a meta-analysis of the data collected of these systems installation costs around the world, the financial inputs used in the RRS model assume an average installation cost of US$7,247 per kilowatt,[4] with a learning rate of 15.5 percent applied. That reduces the cost to US$1,837 per kilowatt in 2030 and to US$1,180 in 2050. This cost is evaluated in comparison to a weighted average of US$1,786 per kilowatt for the conventional technologies (i.e. coal, natural gas, and oil power plants) the solution is replacing. An average capacity factor of 34 percent is used for the solution, compared to 57 percent for conventional technologies. Variable operation and maintenance costs of US$0.07 per kilowatt-hour, and of US$328.1 per kilowatt for fixed operating costs, are considered for this solution, compared to US$0.005 per kilowatt-hour and US$34.65 per kilowatt, respectively, for the conventional technologies.

Integration[5]

Through the process of integrating ocean power with other solutions, the total addressable markets were adjusted to account for reduced demand resulting from the growth of more energy-efficient technologies,[6] as well as increased electrification from other solutions like electric cars  and high-speed rail. Grid emissions factors were calculated based on the annual mix of different electricity generating technologies over time. Emissions factors for each technology were determined through a meta-analysis of multiple sources, accounting for direct and indirect emissions.

Results

Comparing the results from the two modeled scenarios to the Reference Scenario allows us to estimate the climate and financial impacts of increased adoption of ocean power systems. The results for the Scenario 1 show that the marginal first costs compared to the Reference Scenario would be US$200.3 billion from 2020-50, with over US$1 trillion in additional costs over the lifetime of the technologies implemented during the same period. Increasing the use of ocean power from the current figures to 0.86% percent of world electricity generation by 2050 would require an estimated US$350 billion in cumulative first costs. Under the Scenario 1, the adoption of ocean power could reduce 1.4 gigatons of carbon dioxide-equivalent greenhouse gas emissions from 2020-2050, compared to the Reference Scenario.

Due to the uncertainty on the growth of these technologies, the Scenario 2  depicts a similar impact of ocean power technologies, with reductions over 2020-2050 of 1.4 gigatons of carbon dioxide-equivalent.

Discussion

Given the relative immaturity of the wave and tidal industry, it is difficult to predict how it will develop over the next three decades. The uncertainty increases considering the small percentage of wave and tidal systems currently in the global electricity mix and the range of technologies under testing. Once operational, the low carbon footprint of wave and tidal systems makes them increasingly more attractive. Nevertheless, there are many technical, financial, and policy-related challenges which need to be overcome before these systems can be deployed at a large scale in the world. The fact that there are only a couple of utility-scale tidal barrage stations indicates that the deployment may need a big push from governments. Conversely, wave energy’s relative immaturity, coupled with the much shorter timescale on which it operates, is more akin to the early wind energy industry. Once engineers and scientists settle on a design, the market will congeal, prompting true competition and further adoption. The current situation with a smattering of ocean power technology designs means that widespread development and installation is still in a very early stage.

 

[1] For more about the Total Addressable Market for the Electricity Generation Sector, click the Sector Summary: Electricity Generation Sector link below.

[2] Current adoption is defined as the amount of functional demand (i.e. TWh) supplied by the solution in 2018.

[3] To learn more about Project Drawdown’s two adoption scenarios, click the Scenarios link below. For information on Electricity Generation Sector-specific scenarios, click the Sector Summary: Electricity Generation link.

[4] All monetary values are presented in US2014$.

[5] For more on Project Drawdown’s Electricity Generation Sector integration model, click the Sector Summary: Electricity Generation link below.

[6] For example: LED lighting and high efficiency heat pumps.