Table of Contents
- Global Assessment
- Benefits of Wave Energy
As the technology of human kind progresses the need for energy further increases, with it the search for renewable sources of energy had become the priority of various individuals and research institutes. Part of these renewable sources are the oceans and seas. One kind of energy that is produced by the oceans and seas is wave energy. Wave energy possesses a great potential and can benefit the general populace. Converting wave energy into usable energy ensures the absence of air pollution and greenhouse gasses. The power generated through the utilization of wave energy can be considered as decent, if not great. Introduction Science and technology advancements and constant growth in the world population had resulted to the increase in the demand for energy. As time pass by, the depletion of accessible fossil fuels, which in the present is the primary source of energy, will definitely occur therefore the search for a new and effective way of generating energy from renewable sources has always been a priority.
Part of these renewable sources are the oceans and seas. A lot of aspects of the ocean can be exploited to harvest energy such as:
- salinity gradient
- temperature gradient
Wave energy, also known as ocean energy or sea wave energy, is energy harnessed from the ocean or sea waves. Wave energy technologies utilize the kinetic energy generated from the rigorous vertical motion of surface ocean waves to accomplish task such as desalinization of water, pumping of water into reservoirs, and most importantly generation of electricity. Among these examples, generation of electricity by utilizing wave energy, had become a priority since energy is highly sought after in this generation. Nowadays, the technology that converts wave energy into usable energy, has evolved to a phase where different concepts are being tested at a full scale, pre-demonstration phase, and commercial demonstrations are being deployed.
Extracting energy from ocean waves is not a recent phenomenon, as researchers have been studying different concepts or solutions since the 1970s.  Converting wave energy into usable energy has been a subject of research for various scientists throughout history resulting to the registry of more than a thousand patents by the year 1980  and the number is still increasing to the present. Several reviews on wave energy conversion have been published in book form as conference and journal papers, and reports. Several works should be mentioned first such as the pioneering book by McCormick published in 1981, and the books by Shaw, and etc. In Japan, Yoshio Masuda(d. 2009)(Fig. 1), had conducted several studies about wave energy technology and now he can be regarded as the father of modern wave energy technology. He developed a navigation buoy powered by wave energy, equipped with an air turbine, which was later named as oscillating water column (OWC).
Ocean waves can be harnessed into useful energy to reduce our dependence on fossil fuel. Instead of burning depleting fossil fuel reserves, we can obtain energy from a resource as clean, pollution free, and abundant as ocean waves. The technology, though young, exists to convert the power of ocean waves into electricity.
The worldwide wave energy resource, stated in kW power per unit meter of wave crest length, estimated by Dr. Tom Thorpe. The best wave conditions for exploitation are in medium-high latitudes and deep waters (greater than 40 m deep), since wave energy is found to reach power densities of 60-70 kW/m in those locations. For example, countries like Australia, Chile, Ireland, New Zealand, South Africa, the UK and the US have excellent wave resources with average power densities of 40-60 kW/m.
Region Wave Energy TWh/yr Western and Northern Europe 2,800 Mediterranean Sea and Atlantic Archipelagos (Azores, Cape Verde, Canaries) 1,300 North America and Greenland 4,000 Central America 1,500 South America 4,600 Africa 3,500 Asia 6,200 Australia, New Zealand and Pacific Islands 5,600 Total 29,500* The table accounts for only theoretical wave power P≥ 5 kW/m and latitude ≤66. 5º Table 1, shows the theoretical wave energy potential that was the result of a study conducted by Mørk et al. (2010). This estimate is taken under the assumptions that every aspect in generation of energy is in optimum condition. This estimate shows that there is great potential in the utilization of wave energy, assuming that the technology to convert wave energy is highly developed.
Wave Energy Converter Technology Status
There are thousands of patents being registered with regards to wave energy converter technology, as stated earlier in previous sections. However, there are only a handful of them that had made it to actual wave tank model testing, less have progressed to short-term (days to months) small scale tests in natural waters, and even lesser number have progressed to long-term ( >1 year) large scale prototypes in natural waters. Examples of various wave energy converter developers, their location, and the size of there operation can be seen in Table 2 in Appendix.
Benefits of Wave Energy
The benefits offered by wave energy include:
- 1. Providing a new, environmentally friendly and easily assimilated grid connected option for meeting load growth. Since, units of wave energy converters (WEC) can be easily bought or installed once there is a growth in the electric load.
- 2. WEC devices are sited many miles offshore and have a low profile above water, since much of the device is submerged. The submerged transmission cable will be buried and will be landed under the beach using horizontal directional drilling. This can avoid the aesthetic concerns which plague many infrastructure projects.
- 3. Reducing dependence on imported energy supplies, increasing national security and reducing the risk of future fossil fuel price volatility.
- 4. Reducing emissions of greenhouse gases by displacing fossil fuel-based generatio5. Stimulating local job creation and economic development.
Current Costs and Cost Projections
The estimated leveled cost for wave energy farms, with average output of 10 MW, is in between EUR 330-630/MWh. These costs can be considered to be relatively high compared to other forms of renewable sources including offshore wind and tidal current technologies. This is to be expected since the technology to convert wave energy to usable energy is still under its early stages of development. However, wave energy has greater potential compared to other tidal resources and also it is much less site specific, due to these reasons it will be subjected to more research, and further enhancement in the wave energy converter (WEC) technologies will occur. With the advancement in the WEC technologies, it is expected that the cost for utilizing wave energy will fall in the following years.
Wave energy possesses a great potential and can benefit the general populace. Converting wave energy into usable energy ensures the absence of air pollution and greenhouse gasses, which cancels out the environmental issues that other power generating plant often face. The power generated through the utilization of wave energy can be considered as decent, if not great. However, though utilizing wave energy had been the topic of various researches in the past decade, the truth is it has just recently been given the priority. The development of the technology to convert wave energy to usable energy, being only in the early stages, it is understandable that the current cost for wave energy to be expensive but it expected to be more affordable in the following years.