[Annotated] Marine energy

Marine energy or marine power (also sometimes referred to as ocean energy, ocean power, or marine and hydrokinetic^[각주:1] energy) refers to the energy carried by ocean waves, tides, salinity^[각주:2] and ocean temperature differences. The movement of water in the world's oceans creates a vast store of kinetic^[각주:3] energy or energy in motion. This energy can be harnessed to^[각주:4] generate electricity to power^[각주:5] homes, transport and industries. 

The term marine energy encompasses^[각주:6] both wave power i.e.^[각주:7] power from surface waves and tidal power i.e. obtained from the kinetic energy of large bodies of moving water. Offshore^[각주:8] wind power is not a form of marine energy, as wind power is derived from^[각주:9] the wind, even if the wind turbines are placed over water.

The oceans have a tremendous amount of energy and are close to many if not most concentrated populations^[각주:10]. Ocean energy has the potential of providing a substantial amount of new renewable energy around the world. Energy from the ocean is also known as hydroelectricity^[각주:11]. 

Forms of ocean energy 

Renewable 

The oceans represent^[각주:12] a vast and largely untapped^[각주:13] source of energy in the form of surface waves, fluid flow, salinity gradients and thermal. Marine and Hydrokinetic (MHK) or marine energy development in U.S and international waters includes projects using the following devices: 

- Wave power converters in open coastal areas with significant waves;

- Tidal turbines placed in coastal and estuarine^[각주:14] areas;

- In-stream turbines in fast-moving rivers;

- Ocean current turbines in areas of strong marine currents;

- Ocean thermal energy converters in deep tropical waters.

Marine current power

Strong ocean currents are generated from a combination of temperature, wind, salinity, bathymetry^[각주:15] and the rotation of the Earth. The Sun acts as the primary driving force, causing winds and temperature differences. Because there are only small fluctuations in current speed and stream location with no changes in direction, ocean currents may be suitable locations for deploying energy extraction^[각주:16] devices such as turbines.

Ocean currents are instrumental^[각주:17] in determining the climate in many regions around the world. While little is known about the effects of removing ocean current energy, the impacts of removing current energy on the farfield environment may be a significant environmental concern. The typical turbine issues with blade strike, entanglement^[각주:18] of marine organisms and acoustic effects^[각주:19] still exists; however, these may be magnified^[각주:20] due to the presence of more diverse populations of marine organisms using ocean currents for migration purposes. Locations can be further offshore and therefore require longer power cables that could affect the marine environment with electromagnetic^[각주:21] output.

Osmotic^[각주:22] power

At the mouth of rivers where fresh water mixes with salt water, energy associated with the salinity gradient^[각주:23] can be harnessed using pressure-retarded^[각주:24] reverse osmosis process and associated conversion technologies. Another system is based on using freshwater upwelling^[각주:25] through a turbine immersed in^[각주:26] seawater and one involving electrochemical^[각주:27] reactions is also in development.

Significant research took place from 1975 to 1985 and gave various results regarding the economy of PRO and RED plants. It is important to note that small-scale^[각주:28] investigations into salinity power production take place in other countries like Japan, Israel and the United States. In Europe the research is concentrated in Norway and the Netherlands, in both places small pilots are tested. Salinity gradient energy is the energy available from the difference in salt concentration between freshwater with saltwater. This energy source is not easy to understand, as it is not directly occurring in nature in the form of heat, waterfalls, wind, waves or radiation^[각주:29].

Ocean thermal energy

Water typically varies^[각주:30] in temperature from the surface warmed by direct sunlight to greater depths where sunlight cannot penetrate. This differential^[각주:31] is greatest in tropical waters, making this technology most applicable^[각주:32] in water locations. A fluid is often vaporized^[각주:33] to drive a turbine that may generate electricity or produce desalinized^[각주:34] water. Systems may be either open-cycle, closed-cycle, or hybrid.

Tidal^[각주:35] power

The energy from moving masses of water - a popular form of hydroelectric power generation. Tidal power generation comprises three main forms, namely: tidal stream power, tidal barrage^[각주:36] power and dynamic tidal power.

Wave power

Solar energy from the Sun creates temperature differentials that result in wind. The interaction between wind and the surface of water creates waves, which are larger when there is a greater distance for them to build up. Wave energy potential^[각주:37] is greatest between 30 degrees and 60 degrees latitude in both hemispheres on the west coast because of the global direction of wind. When evaluating wave energy as a technology type, it is important to distinguish between the four most common approaches: point absorber buoys, surface attenuators^[각주:38], oscillating^[각주:39] water columns^[각주:40] and overtopping^[각주:41] devices. 

The wave energy sector is reaching a significant milestone^[각주:42] in the development of the industry, with positive steps towards commercial viability^[각주:43] being taken. The more advanced device developers are now progressing beyond single unit demonstration devices and are proceeding to^[각주:44] array ^[각주:45]development and multi-megawatt projects. The backing^[각주:46] of majority utility companies is now manifesting^[각주:47] itself through partnerships within the development process, unlocking^[각주:48] further investment and, in some cases, international co-operation.

At a simplified level, wave energy technology can be located near-shore  and offshore. Wave energy converters^[각주:49] can also be designed for operation in specific water depth conditions: deep water, intermediate water or shallow water. The fundamental device design will be dependent on^[각주:50] the location of the device and the intended resource characteristics.

Non-renewable 

Petroleum^[각주:51] and natural gas beneath the ocean floor are also sometimes considered a form of ocean energy. An ocean engineer directs all phases of discovering, extracting and delivering offshore petroleum (via oil tankers and pipelines) a complex and demanding^[각주:52] task. Also centrally important is the development of new methods to protect marine wildlife^[각주:53] and coastal regions against the undesirable^[각주:54] side effects of offshore oil extraction.

1. hydrokinetic ; [형용사] 유체(流體) 운동의; 유체 동력학의. (또는 hydrokinetical) [본문으로]
2. salinity ; [명사] 염분, 염분 함유도, 염도 [본문으로]
3. kinetic ; [형용사] (주로 명사 앞에 씀) (전문 용어) 운동의, 운동에 의해 생기는 [본문으로]
4. harness ; 2. (동력원 등으로) 이용[활용]하다 [본문으로]
5. power ; 1. SUPPLY ENERGY | [타동사][VN] (주로 수동태로) 동력을 공급하다, 작동시키다 [본문으로]
6. encompass ; 1. SUPPLY ENERGY | [타동사][VN] (주로 수동태로) 동력을 공급하다, 작동시키다 [본문으로]
7. i.e. ; [약어] 즉(라틴어 id est에서) [본문으로]
8. offshore ; 2. (바람이) (육지에서) 바다 쪽으로 부는 [본문으로]
9. derive ; 2. <단어·관습 등이> …에서 비롯되다, <사람이> …의 유래를 찾다(trace);[종종 수동형으로] …에 기원을 두다, …에서 나오다 ((from)); 추론[추리]하다; <영화 등을> (소설에서) 각색하다 ((from)) [본문으로]
10. concentrated population ; 밀집된 인구 [본문으로]
11. hydroelectricity ; [명사] 수력 전기 [본문으로]
12. represent ; 4. BE EXAMPLE OF | [타동사][VN] [수동태로는 안 씀] (…의) 표본[전형]이 되다, (…을) 표현하다[나타내다] [본문으로]
13. untapped ; [형용사] (이용할 수 있는 것을) 아직 손대지[사용하지] 않은 [본문으로]
14. estuarine ; [형용사] 강어귀(지역)의; 하구에 형성된; 하구(지역)에 알맞은 ;; [éstʃuəràin] [본문으로]
15. bathymetry ; [명사] 수심 측량술, 측심학(測深學) ;; [bəθímətri] [본문으로]
16. energy extraction ; 에너지 추출 [본문으로]
17. instrumental ; 1. ~ (in sth/in doing sth) (어떤 일을 하는 데) 중요한 [본문으로]
18. entanglement ; [명사] (다른 사람・국가와의) 복잡한[얽히고설킨] 관계 [본문으로]
19. acoustic effect ; [명사] (다른 사람・국가와의) 복잡한[얽히고설킨] 관계 [본문으로]
20. magnify ; 3. (중요성・심각성을) 과장[확대]하다 [본문으로]
21. electromagnetic ; [형용사] (물리) 전자기의 [본문으로]
22. osmotic ; [형용사] (물리·화학) 삼투(성)의 [본문으로]
23. salinity gradient ; 농도차이 ;; gradient ; 2. (전문 용어) (두 지역간 온도・기압 등의) 변화도[증감률] [본문으로]
24. pressure-retarded ; 압력 지연된 [본문으로]
25. upwelling ; [명사] (하층 해수의) 용승(湧昇) [본문으로]
26. immerse ; 1. ~ sb/sth (in sth) (액체 속에) 담그다 [본문으로]
27. electrochemical ; [형용사] 전기 화학의 [본문으로]
28. small-scale ; [형용사] 조직・활동 등이 소규모의 [본문으로]
29. radiation ; 2. [U] (열・에너지 등의) 복사 [본문으로]
30. vary ; 1. [자동사][V] ~ (in sth) (한 무리의 비슷한 것들이) (크기・모양 등에서) 서로[각기] 다르다 [본문으로]
31. differential ; 1. ~ (between A and B) (양・가치・소득의) 차이, 격차 [본문으로]
32. applicable ; [대개 명사 앞에는 안 씀] ~ (to sb/sth) 해당[적용]되는 [본문으로]
33. vaporize ; [타동사][VN] (전문 용어) 증발[기화]하다; 증발[기화]시키다 [본문으로]
34. desalinize ; [타동사][VN] (전문 용어) 증발[기화]하다; 증발[기화]시키다 ;; desalt [본문으로]
35. tidal ; [형용사] 조수의 [본문으로]
36. barrage ; 3. [C] 댐, 보 [본문으로]
37. potential ; 2. [U] 잠재력 [본문으로]
38. attenuator ; [명사] (전문 용어) 감쇠기(무선 신호의 감도를 줄이는 장치) [본문으로]
39. oscillate ; 2. (물리) (두 지점 사이를) 왔다 갔다 하다[진동하다] [본문으로]
40. column ; 2. 기둥 (모양의 것) [본문으로]
41. overtop ; 1. …의 위에 높이 솟다, …보다 높다 [본문으로]
42. milestone ; 1. (mile・post 특히 美) 중요한[획기적인] 단계[사건] [본문으로]
43. viability ; [U] 생존 능력; (특히 태아·신생아의) 생육[생존]력; (계획 등의) 실행 가능성 [본문으로]
44. proceed to ; …으로 나아가다, 향하다; …에 이르다, …이 되다 [본문으로]
45. array ; 1. (보기 좋게) 배열하다[진열하다] [본문으로]
46. backing ; [명사] 지원 [본문으로]
47. manifest ; 2. [타동사][VN] ~ itself (in sth) 나타나다, 분명해지다 [본문으로]
48. unlock ; 2. (비밀 등을) 드러내다 [본문으로]
49. converter ; 1. 전환시키는 사람[것], 컨버터 [본문으로]
50. be dependent on ; …에게 의존하고 있는. [본문으로]
51. petroleum ; [명사] 석유 ;; [pə|troʊliəm] [본문으로]
52. demanding ; [형용사] 일이 부담이 큰, 힘든 [본문으로]
53. wildlife ; [명사] 야생 동물 [본문으로]
54. undesirable ; 원하지 않는, 달갑지 않은; 바람직하지 않은 [본문으로]