Market challenges experienced in Ocean energy systems are:
- Challenges in Ocean Energy Systems
- Long Development Timescales
- Grid Connection
- Lack of Performance Assessment Standards
- Challenges Specific to Wave Energy Systems
- High Cost
- Variable Energy Supply
- Limited Locations
- Design Bottlenecks
- Effects on Marine Life
- Requirement of High-strength Device
- Technology Development
- Challenges Specific to Tidal Energy Systems
- High cost
- Effects on ecosystem
- Regional limitations
- Time limitations
Challenges in Ocean Energy SystemsLong Development Timescales
The development timescales for ocean-energy projects can vary greatly, with some technologies remaining at the development stage for decades and others progressing from concept to prototype in lesser time.
With few commercial projects having been completed to date, the standard timescales for projects are difficult to assess. The typical timescale for a commercial project is outlined below.
Connecting wave energy devices to the electricity transmission grid presents many problems of its own, with underwater cables. Maintenance of these cables is expensive and necessitates the need for experienced and skilled workers. The cost of grid connection constitutes a large percentage of the capital cost of ocean energy devices, as it must be paid for by the developer. For this reason, the development of ‘Ocean energy farms’ is essential to keep the infrastructure costs to a minimum and these must be developed close to existing national grid connection points.
Lack of Performance Assessment Standards
The marine renewable industry lacks standard methodologies for resource assessment and standards for performance assessment in the varied conditions of the ocean. The introduction of performance assessment standards can be used to compare the different marine energy technologies and decisions can be made about the requirements for additional developments and appropriate applications.Challenges Specific to Wave Energy Systems
High Cost - Wave power is currently very expensive to produce. Between the high costs of devices needed to harness the power of the waves to the expensive efforts behind efficient generation of power from waves, it may be some time before the price of wave power can be competitive with power generation from coal or nuclear power plants.
Variable Energy Supply - The energy supply depends on waves and their intensities, which are variable. Even in the most active wave areas, there are many days with little wave activity. On days that have good wave activity, wave levels can vary. Resolving intermittency problems to attain reliable energy output can double and even triple the cost of power.
Limited Locations - While waves cover virtually every mile of water on the planet, economically accessible wave power is found only in coastal areas. Some areas are better than others and the best resources tend to be found only in the specific regions.
Design Bottlenecks - As wave power is scattered and the size of individual waves is limited, all designs are necessarily modular. Harnessing wave energy probably will not be done with a few, very large generators. Large-scale use of wave energy will likely involve thousands of small generators. Wave power is more energy dense than wind power, but it is still diffuse. Research data for the US shows that even in high wave energy dense areas such as the Pacific Northwest, one can expect energy production rates of about 1.5 MW for every 100 feet of shoreline occupied by generators. By comparison, a large fossil fuel plant of 1,000 MW capacity would occupy about two hundred acres. Installing a similar capacity using on shore wave power would occupy over 12.5 miles of shoreline; and that’s in the best areas like the Pacific Northwest.
Effects on Marine Life - The effects of wave energy systems on marine life are not fully known, and these could prove to be bottlenecks
Requirement of High-strength Device - One of the most challenging problems is the construction of devices that can withstand wave attacks over and over again. Designing and building a machine that can last for years despite being mashed by pounding waves is a difficult task, and may make or break the future of wave power.
Technology Development - The development process primarily consists of three phases. It begins with small-scale prototype devices that typically have a low capacity. Successful devices lead on to larger capacity prototypes, at this stage outside funding from government or private investors is possible for the most promising devices. The final stage, representing the culmination of development is the production of full-scale grid connected devices that will, in some cases, be deployed in farm style configurations. Only few prototype wave devices are close to entering the final stage and commercial deployment.
Despite the fact that a number of wave energy devices are getting closer to full-scale deployments, the fact remains that little real-world operational experience has yet been gained. Large-scale demonstrations are required in order to test survivability and efficiency issues that have not yet been resolved. It is difficult to assess potential of a system until it is tested in its final state.
A tiny proportion of all wave energy concepts are realisable to a commercial level. Drawing together, resources will ensure that the devices that do progress stand the best chance possible of succeeding. The SME (Small and Medium Enterprises) dominance of the sector is a barrier to development, as limited resources in many cases limit progress. These small companies are, in most cases, unwilling to collaborate as they naturally wish to protect their investment.
Challenges Specific to Tidal Energy Systems
The problems and barriers mentioned below are relevant to all forms of tidal projects (barrages, streams and lagoons), unless specifically mentioned.
- High cost - The main detriment of tidal energy is the cost; tidal plants are expensive to build
- Effects on ecosystem – Presence of tidal plants can result in damages such as reduced flushing, winter icing and erosion, which can change the vegetation of the area and disrupt the balance.
- Regional limitations - Similar to other ocean energies, tidal energy has several prerequisites that make it available only in a small number of regions. For a tidal power plant to produce electricity effectively (about 85% efficiency), it requires a basin or a gulf that has a mean tidal amplitude (the differences between spring and neap tide) of 7 meters or above. It is also desirable to have semi-diurnal tides where there are two high and low tides every day. Thus, there are not too many suitable sites for tidal barrages.
- Time limitations - Tidal provides power for about ten hours each day, when the tide is actually moving in or out. So, it does not provide energy for electricity all through the day.
- Problems specifically related to tidal barrages
- Tidal barrages may block outlets to open water. Although locks can be installed, this is often a slow and expensive process.
- Barrages affect fish migration and other wildlife- many fish like salmon swim up to the barrages and are killed by the spinning turbines. Barrages may also destroy the habitat of the wildlife living near it
- Barrages may affect the tidal level - the change in tidal level may affect navigation, recreation, and cause flooding of the shoreline