Sistem Pembangunan Perlindungan Pantai Yang Dikombinasikan Dengan sistem Pembangunan Pembangkit Energi Listrik Terbarukan (Bagian I)

Oleh : Busaeri ( ERRY)

Perancang Sistem Teknologi Energi Kelautan 

Ancaman Abrasi : Camplong, Sampang, Madura, Jatim

"The protection of coastlines is a necessity for the life of millions of people living near the ocean. To harness the oceans' vast wave power resource - and even more: to connect the use of this renewable energy with the protection of the shore - is an old dream of mankind. Efforts to construct a wave energy breakwater, a breakwater also able to produce usable forms of energy from the wave power, have been made for years and the first commercial realizations will be built in the next decade." (Prof. Dr.-Ing. habil. Kai-Uwe Graw)  

Negara Indonesia adalah negara kepulauan, total pulau di Indonesia sebanyak 17.508 pulau dengan panjang garis pantai ± 95.000 km dan mengalami berbagai permasalahan dalam bidang pengamanan pantai, diantaranya adalah lebih dari 20% garis pantai di Indonesia mengalami kerusakan.

Abrasi pantai, kalau tidak segera ditangani  berpotensi mengancam keselamatan jiwa manusia dan merusak prasarana umum jalan raya, bangunan rumah penduduk sekitar, areal pertanian dan pusat kegiatan masyarakat yang terletak dekat garis pantai.

Banyak cara mengenai model pembangunan pengaman dan pelindung pantai, tergantung dari jenis struktur dan material pantai itu sendiri. Bisa dengan : 

• menanam pohon bakau (mangrove),
• pembuatan breakwater, dan bahkan ada yang sampai membuat 
• dinding laut (seawall). 

Membangun pengaman pantai membutuhkan anggaran yang relatif besar, sementara anggaran dana yang disediakan pemerintah masih sangat terbatas.   Terkadang ada daerah yang  kerusakan pantainya dibiarkan lama terbengkalai karena keterbatasan anggaran, padahal  membangun pengaman pantai sangat berhubungan erat dengan keselamatan jiwa manusia, dan kelestarian alam dan lingkungan. 

Kerusakan Infrastrukrur Jalanan

Abrasi Pantai  Kawasan Pesisir Pantai Utara Indramayu

KOORDINASI KEMENTERIAN

Membangun pengaman pantai adalah kewajiban pemerintah, dan tentunya hal ini membutuhkan anggaran yang sangat besar, dan dalam hal ini adalah menjadi ruang lingkup bidang kegiatan kementerian Pekerjaan Umum (PU).

Saya mengandai-andai. Seandainya kementerian Pekerjaan Umum dapat berkoordinasi dengan kementerian Energi dan Sumber Daya Mineral (ESDM), dan kementerian KLH, serta Perusahaan Listrik Negara (PLN), baik ditingkat pusat atau daerah, dapat bersama-sama duduk memikirkan hal ini, yaitu " membangun sistem pengaman atau perlindungan pantai yang dapat menghasilkan energi listrik".

Pantai Manado, Sulawesi Utara

Program ini harus dilihat dari prospek dan pandangan yang jauh untuk kebaikan dan perbaikan di masa depan, yaitu perbaikan lingkungan,  meningkatnya kebutuhan sumber energi listrik dimasa mendatang, dan kemandirian daerah untuk menghasilkan energi listrik yang bersih lingkungan, serta untuk mengurangi pemanasan global.

Besarnya potensi untuk menghasilkan energi listrik dari sumber kelautan ini, seharusnya menjadi dasar bagi keseriusan pemerintah untuk memikirkan hal ini agar menjadi program kerja.


Setidak-tidaknya, proyek ini bisa disusun dan dirancang dengan membuat percontohan atau semacam pilot project, yaitu dibuat dalam skala prototipe. Skala prototipe inilah yang nantinya menjadi dasar untuk  dibangun dalam skala yang lebih besar.


NILAI TAMBAH (ADD VALUE)
Keuntungan atau nilai tambah  dari program ini  adalah :

1. Dapat melindungi masyarakat di wilayah pantai dari hantaman gelombang laut yang dapat terjadi sewaktu-waktu,
2. Dapat melindungi pantai dari erosi dan abrasi, 
3. Menjadi alternatif untuk mengatasi krisis energi listrik di masa mendatang
4. Dapat dirancang untuk proses pengelolaan air bersih ( fresh water )
5. Turut serta dalam program internasional dalam mengurangi pemanasan global. 
6. Didesain agar nyaman dan indah dipandang mata, agar memiliki nilai tambah untuk wisata teknologi.  
7. Menghemat biaya, karena nilai investasi yang ditanam untuk program ini sepanjang waktu akan menghasilkan dana dari listrik yang dihasilkan, seandainya listrik listrik tersebut nantinya akan dijual. 
8. Dapat diminati oleh pihak swasta, karena adanya prospek bisnis dari sisi penjualan energi listrik. Sehingga di masa mendatang, membangun pengaman pantai bisa dilakukan oleh pihak swasta dan tidak lagi hanya bersumber dari dana pemerintah.

Disamping memiliki nilai tambah yang telah disebutkan di atas, secara aspek teknologi  energi kelautan juga  ada kelebihannya atau keunggulan yaitu:

1. Mudah untuk melakukan pemeliharaan (maintenance), karena generator  bisa disimpan di daratan. 
2. Tidak perlu menggunakan kabel daya bawah laut, dan
3. Tidak perlu menggunakan sistem mooring, karena titik penguat konnstruksi bisa ikut bersatu pada system konstruksi breakwater.
4. Dapat menghemat biaya. 

Abrasi Pesisir  Pantai Bengkulu

Jadi, walaupun membangun pengaman pantai membutuhkan anggaran besar, tetapi dana tersebut memberikan manfaat ganda,  karena adanya energi listrik yang dihasilkan. Dan bahkan kedepan,  listrik tersebut bisa dijual ke PLN, karena  potensi energi listrik dari gelombang laut berkekuatan sangat besar. 

Pertanyaan inti berikutnya  : 

1. Bagaimana  cara membangun sistem pengaman atau perlindungan pantai agar dapat menghasilkan energi listrik? dan sistem teknologi apa yang akan diterapkan?
2. Apakah feasible atau seberapa efesien membangun pengaman pantai dikombinasikan dengan sistem pembangkit listrik terbarukan?

(Bersambung ke Bagian II, Klik disini)

World Renewable Energy Congress Indonesia 2011

By : Indonesian Renewable Energy Society (IRES)/Masyarakat Energi Terbarukan Indonesia (METI) 

Indonesian Renewable Energy Society (METI – IRES) has launched the plan for organizing the international gathering of experts and practitioners of renewable energy  and energy efficiency, World Renewable Energy Congress – Indonesia – International Conference and Exhibition on Renewable Energy and Energy Efficiency, Bali 2011 (WREC – INDONESIA 2011) which will be held on 17 – 19 October 2011 at Bali Nusa Dua Convention Center (BNDCC), Nusa Dua.

Acting as host of WREC – INDONESIA 2011 in Bali is METI – IRES in cooperation with World Renewable Energy Network (WREN) based in United Kingdom (UK).

Bearing the theme “Boosting the Use of Low Carbon Energy for a Better World”, WREC – INDONESIA 2011 is expected to attract some 1000 participants/delegates from all over the world.

The Chairman of Indonesian Renewable Energy Society (METI – IRES), Ir. Hilmi Panigoro, MSc., emphasized the importance of Indonesia being host of World  Renewable Energy Congress – Indonesia – International Conference and Exhibition on Renewable Energy and Energy Efficiency, Bali 2011 (WREC – INDONESIA 2011).

 It will promote the investment of clean and renewable energy in Indonesia as well as highlight the strategic role energy efficiency has in reducing dependency on fossil energy and managing its negative impacts on the environment.

The Conference will also discuss energy efficiency as a strategic component essential to the world strategy for future energy management and to efforts to reduce greenhouse gas emissions, which cause the global climate change issues we are facing at the moment.

WREC – INDONESIA 2011 is a forum for government officials,  decision makers and regulators, politicians and legislators, scientists, experts and academicians, NGO, business executives, bankers and industry players, developers, operators, and entrepreneurs dealing with renewable energy and energy efficiency businesses.

The Conference is expected to function as a place to study and exchange valuable experience and knowledge in new and renewable energy as well as energy efficiency for business players, electrical services operators (PLN and their working partners), academicians, community and practitioners of energy, both in the central and local arenas.

In line with the Conference theme and together with the newly established Directorate General of New and Renewable Energy and Energy Conservation, Ministry of Energy and Mineral Resources of the Republic of Indonesia, the Conference is expected to build momentum and boost more effective utilization of new and renewable energy.

There are a number of topics in new and renewable energy to be discussed in WREC – INDONESIA 2011 in Bali, namely Geothermal, Hydro Energy, Solar Energy, Biomass, Ocean Energy, Wind Energy. In energy efficiency, topics to be discussed include development and technology applied which could save energy in industry and commerce as well as transportation. Moreover, other topics to be discussed are Low Carbon Technology, New and Renewable Energy Financing, Environment Management and Carbon Trade.  Conference participants will also be offered a visit to some new and renewable energy projects located around Bali and Lombok (West Nusa Tenggara).

WREC – INDONESIA 2011 is supported by a number of Indonesian ministries and institutions related to the development and utilization of new and renewable Energy, namely Coordinating Ministry of Economic Affairs, Ministry of Energy and Mineral Resources, State Ministry of Research and Technology, Ministry of Environment, Ministry of Culture and Tourism, Agency for Assessment & Application and Technology (BPPT), the National Energy Council, Islamic Educational, Scientific and Cultural Organization (ISESCO), and University of Maryland.  Moreover, the Conference is also supported by the private sector, both local and international.

Technology Types Of Ocean Energy Conversion (Jenis Teknologi Konversi Energi Laut )

Ada 4 Jenis Sistem Konversi Energi Kelautan,  yaitu (1). energi ombak atau gelombang laut, (2). energi pasang surut,  (3). energi arus laut, dan (4). OTEC, Ocean Thermal Energy Conversation, yaitu konversi energi perbedaan temperatur yang terjadi antara permukaan laut dan dasar laut. Permukaan laut jelas memiliki temperatur lebih panas jika dibandingkan dengan dasar laut. Perbedaan temperatur yang tinggi dapat mudah ditemukan di perairan tropis. Perbedaan ini mampu mencapai 20⁰-25⁰ C. Air panas dan air dingin kemudian dialirkan ke permukaan melalui pipa terpisah yang kemudian bisa dimanfaatkan.( Abstraksi Indonesia )

For further detail study can see here : Ocean energy technology  and here : Ocean energy : Global tecnology development status.

Four types of ocean energy conversion exist:

(1). wave energy, (2). tidal energy, (3). marine current energy, and (4). ocean thermal energy conversion.

Ocean Treader

Wave Energy

Wave energy is generated by the movement of a device either floating on the surface of the ocean or moored to the ocean floor. Many different techniques for converting wave energy to electric power have been studied. Wave conversion devices that float on the surface have joints hinged together that bend with the waves. This kinetic energy pumps fluid through turbines and creates electric power. Stationary wave energy conversion devices use pressure fluctuations produced in long tubes from the waves swelling up and down. This bobbing motion drives a turbine when critical pressure is reached. Other stationary platforms capture water from waves on their platforms. This water is allowed to runoff through narrow pipes that flow through a typical hydraulic turbine. Wave energy is proving to be the most commercially advanced of the ocean energy technologies with a number of companies competing for the lead.

Tidal Energy 

The tidal cycle occurs every 12 hours due to the gravitational force of the moon. The difference in water height from low tide and high tide is potential energy. Similar to traditional hydropower generated from dams, tidal water can be captured in a barrage across an estuary during high tide and forced through a hydro-turbine during low tide. To capture sufficient power from the tidal energy potential, the height of high tide must be at least five meters (16 feet) greater than low tide.  There are only approximately 20 locations on earth with tides this high. The Bay of Fundy between Maine and Nova Scotia features the highest tides in the world, reaching 17 meters (56 feet). This area has the potential to produce 10,000 MW

Current Energy

Marine current is ocean water moving in one direction. In the U.S., it is found primarily off the coast of Florida. This ocean current is known as the Gulf Stream. Tides also create currents that flow in two directions. Kinetic energy can be captured from the Gulf Stream and other tidal currents with submerged turbines that are very similar in appearance to miniature wind turbines. As with wind turbines, the constant movement of the marine current moves the rotor blades to generate electric power. 

Ocean Thermal Energy Conversion

 Ocean thermal energy conversion, or OTEC, uses ocean temperature differences from the surface to depths lower than 1,000 meters, to extract energy. A temperature difference of only 20°C (36°F) can yield usable energy. Research focuses on two types of OTEC technologies to extract thermal energy and convert it to electric power: closed cycle and open cycle. In the closed cycle method, a working fluid, such as ammonia, is pumped through a heat exchanger and vaporized. This vaporized steam runs a turbine. The cold water found at the depths of the ocean condenses the vapor back to a fluid where it returns to the heat exchanger. In the open cycle system, the warm surface water is pressurized in a vacuum chamber and converted to steam to run the turbine. The steam is then condensed using cold ocean water from lower depths

Illustration of OTEC plant ( Xenesys Inc.)

Sumber : http://www.nrel.gov/docs/fy09osti/44200.pdf