Kawah Gunung Tangkuban Parahu, Bandung, Jawa Barat. Indonesia
Intro:
Pembangkit Listrik Tenaga Panas Bumi adalah Pembangkit Listrik (Power generator) yang menggunakan Panas bumi (Geothermal) sebagai energi penggeraknya. Indonesia dikaruniai sumber panas Bumi yang berlimpah karena banyaknya gunung berapi di indonesia, dari pulau-pulau besar yang ada, hanya pulau Kalimantan saja yang tidak mempunyai potensi panas Bumi.
Untuk membangkitkan listrik dengan panas Bumi dilakukan dengan mengebor tanah di daerah yang berpotensi panas Bumi untuk membuat lubang gas panas yang akan dimanfaatkan untuk memanaskan ketel uap (boiler) sehingga uapnya bisa menggerakkan turbin uap yang tersambung ke Generator.
Untuk panas Bumi yang mempunyai tekanan tinggi, dapat langsung memutar turbin generator, setelah uap yang keluar dibersihkan terlebih dahulu. Pembangkit listrik tenaga panas Bumi termasuk sumber Energi terbaharui.
Geothermal Energy
Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. The Geothermal energy of the Earth's crust originates from the original formation of the planet (20%) and from radioactive decay of minerals (80%).
The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface.
The adjective geothermal originates from the Greek roots γη (ge), meaning earth, and θερμος (thermos), meaning hot.
At the core of the Earth, thermal energy is created by radioactive decay and temperatures may reach over 5000 degrees Celsius (9,000 degrees Fahrenheit). Heat conducts from the core to surrounding cooler rock. The high temperature and pressure cause some rock to melt, creating magma convection upward since it is lighter than the solid rock.
The magma heats rock and water in the crust, sometimes up to 370 degrees Celsius (700 degrees Fahrenheit).
From hot springs, geothermal energy has been used for bathing since Paleolithic times and for space heating since ancient Roman times, but it is now better known for electricity generation. Worldwide, about 10,715 megawatts (MW) of geothermal power is online in 24 countries.
An additional 28 gigawatts of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications.
Geothermal power is cost effective, reliable, sustainable, and environmentally friendly, but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels.
As a result, geothermal power has the potential to help mitigate global warming if widely deployed in place of fossil fuels.
Direct application
In the geothermal industry, low temperature means temperatures of 300 °F (149 °C) or less. Low-temperature geothermal resources are typically used in direct-use applications, such as district heating, greenhouses, fisheries, mineral recovery, and industrial process heating. However, some low-temperature resources can generate electricity using binary cycle electricity generating technology.
Approximately 70 countries made direct use of 270 petajoules (PJ) of geothermal heating in 2004. More than half went for space heating, and another third for heated pools. The remainder supported industrial and agricultural applications. Global installed capacity was 28 GW, but capacity factors tend to be low (30% on average) since heat is mostly needed in winter.
The above figures are dominated by 88 PJ of space heating extracted by an estimated 1.3 million geothermal heat pumps with a total capacity of 15 GW. Heat pumps for home heating are the fastest-growing means of exploiting geothermal energy, with a global annual growth rate of 30% in energy production.
Direct heating is far more efficient than electricity generation and places less demanding temperature requirements on the heat resource. Heat may come from co-generation via a geothermal electrical plant or from smaller wells or heat exchangers buried in shallow ground.
As a result, geothermal heating is economic at many more sites than geothermal electricity generation. Where natural hot springs or geysers are available, the heated water can be piped directly into radiators. If the ground is hot but dry, earth tubes or down hole heat exchangers can collect the heat.
But even in areas where the ground is colder than room temperature, heat can still be extracted with a geothermal heat pump more cost-effectively and cleanly than by conventional furnaces.
These devices draw on much shallower and colder resources than traditional geothermal techniques, and they frequently combine a variety of functions, including air conditioning, seasonal energy storage, solar energy collection, and electric heating.
Geothermal heat pumps can be used for space heating essentially anywhere.
Geothermal heat supports many applications. District heating applications use networks of piped hot water to heat many buildings across entire communities.
More than 72 countries have reported direct use of geothermal energy, Iceland being the world leader. 93% of its homes are heated with geothermal energy, saving Iceland over $100 million annually in avoided oil imports. Reykjavík, Iceland has the biggest district heating system on the globe. Once known as the most polluted city in the world, it is now one of the cleanest due to geothermal energy.
1:Reservoir, 2:Pump House
3:Heat Exchanger, 4:Turbine Hall
5:Production Well, 6:Injection Well
7:Hot Water to District Heating, 8:Porous Sediments
9:Observation Well, 10:Crystalline Bedrock
Potensi Energi Panas Bumi di Indonesia
Salah satu potensi sumber energi terbesar di Indonesia adalah energi panas bumi. Indonesia setidaknya menyimpan 28.994 MWe (megawatt-elektrikal) potensi panas bumi, namun hingga saat ini hanya sekitar 4 % atau 1,2 MWe yang telah dimanfaatkan. Jumlah ini masih sangat jauh jika dibandingkan dengan Filipina yang telah mengeksplorasi hingga 70% dari total potensi panas buminya.
Badan Survey Geologi Kolonial Belanda (DGCS) pertama kali memetakan potensi energi panas bumi di awal abad 20. Pada tahun 1969 eskplorasi lebih lanjut dilakukan oleh Survey Geologi Indonesia. Pada tahun 2011 tercatat dari sekitar 276 area geothermal di Indonesia, 37 diantaranya merupakan area pertambangan
(WKP [Wilayah Kerja Pertambangan]) dengan potensi panas bumi sebesar 7.376 MWe.
Semakin pesatnya pertumbuhan ekonomi di Indonesia menyebabkan adanya peningkatan kebutuhan energi, sementara hingga saat ini, Indonesia masih sangat bergantung pada sumber energi fosil. Jika hal ini terus terjadi, maka diperkirakan 2 atau 3 dekade yang akan datang, akan terjadi krisis energi yang semakin parah.
Potensi geothermal di Indonesia tidak hanya mengingat cadangannya yang sangat besar, namun juga pertimbangan ekonomi dan ketahanan energi nasional jika sektor ini bisa dikembangkan dan dikelola dengan baik. Pengurangan emisi yang bersumber dari pembakaran sumber energi fosil dan pengurangan beban subsidi energi dapat dilakukan.
Geothermal yang bersifat site specific sangat menguntungkan mengingat sifatnya yang tidak dapat disimpan dan tidak dapat ditransportasikan dalam jarak yang jauh membuat sumber ini tidak dapat menjadi komoditi ekspor, sehingga akan lebih stabil dan terhindar dari fluktuasi harga energi di dunia.
Keuntungan lain dari pemanfaatan geothermal adalah rendahnya emisi yang dihasilkan.
Beberapa studi menunjukkan bahwa peningkatan kapasitas geothermal dapat mengurangi tingkat emisi gas rumah kaca (GRK) terutama CO2. Menurut laporan WWF’s Ring of Fire Geothermal Scenario, potensi geothermal diperkirakan dapat mengurangi emisi tahunan hingga 13,6 juta ton CO2 pada tahun 2015 dan 19,8 juta ton pada tahun 2020.
"Potensi Energi Panas Bumi di Indonesia adalah 40% dari Kapasitas Total Energi Panas Bumi Dunia jika kita mampu mengoptimalkan energi ini maka Insha Allah Bangsa ini akan menuai Kemerdekaan Energi"
~Arip Nurahman~
Sources:
1. http://en.wikipedia.org/wiki/Geothermal_energy
2. http://en.wikipedia.org/wiki/Geothermal_electricity
3. http://www.ebtke.esdm.go.id/
4. Arip Nurahman Notes
Ucapan Terima Kasih Kepada:
Sahabat-sahabatku:
Ridwan Firdaus (Geografi Universitas Negeri Jakarta), Ade Akhyar Nurdin (Teknik Geologi Universitas Jendral Soedirman), Widia Prima (Teknik Sipil, Sekolah Tinggi Teknologi Garut), Deni Nugraha (Ilmu Pemerintahan STISIP Banjar), Ismail Muhammad S. (Sosial Ekonomi Pertanian Universitas Jendral Soedirman), Farid Waliyuddin R. (Sekolah Tinggi Akuntansi Negara), Muhlaso Dian A. (Institute Pemerintahan Dalam Negeri).
Kepada FORSALIM
Dan semua alumni "paguron mosque keeper" Manbaul Ulum SMAN 1 Banjar
Photo by: Kang Agus Haeruman, S.Si.
