« '''' l E N CO THE DONG COP INHCNC CI CHO NHU CAU NANC LUONC THE KY 21 Nhieu lieu hda thach (than, dau md vd khi thien nhien) la ngudn tai nguyen thien nhien quan trpng nhat eua the ky qua va cho den ea[.]
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l E N CO T H E
Nhieu lieu hda thach (than, dau md vd khi
thien nhien) la ngudn tai nguyen thien
nhien quan trpng nhat eua the ky qua va
cho den ea ngay nay, cung cap hon 85% nhu
cau nang lupng cho sy van hanh cua nen kinh
te, ehu yeu la bao dam nhu cau dien nang, nhu
cau nhiet nang va nhu cau nhien lieu dpng co
cua mpi hoat ddng con ngudi Tuy nhien, tru
lupng cac ngudn nang lupng hoa thach la cd han
va sy can kiet cua chung cung dang dupe dy
bao bdi nhieu tinh todn khoa hpc Vi vay, da
nhieu nam nay cac nha khoa hpc the gidi dau tu
nhieu cong sdc cho viec tim nhdng dang ndng
lupng khac vdi hy vpng cd the thay the mot phan
hay todn bp cac nhien lieu hoa thach truyen
thdng, hoa giai cac thach thdc ndi tren Sy tim
kiem ndy da va dang dem lai nhieu thanh qua
quan trpng day trien vpng
Td giua the ky 20 bien da trd thanh ngudn
cung cap dau md va khi thien nhien cho the gidi
ngay cang nhieu Hien nay cong viec thdm dd vd
khai thae dau khi d day bien dang ngdy cang phat
tnen va ngudi ta da cd the khai thde nhung md
dau va md khi d nhCing vung bien cd myc nudc
sau den ca nghin met Vd iinh vyc dau khi bien
van dang tiep tuc tien ra nhijng vung nude sau, xa
bd, Tuy nhien, bai viet nay xin phep khong de cap
den ddng gdp ngay edng tang cua bien trong ITnh
vyc dau khf, ma ehi diem qua mot sd nhung tiem
nang to Idn khac cua bien kha died the gdp phan
phat trien nen ndng luong cho nhan loai trong the
ky nay va nhung the ky tiep theo
TSKH. H 6 SITHOANG, TRAN MANH TR[ Hydrat metan:
Gan day ngudi ta ndi nhieu den ngudn tdi nguyen het sye to Idn dudi day bien Id cac via hydrat metan Hydrat metan la nhung tinh the, trong dd cac phan ty nude (H2O) lien ket vdi nhau thdng qua lye hut giua nguyen ty H cua phan td nay va nguyen ty O eua phdn ty khac (gpi la lien ket hydro) de tao thanh nhiJng hoc ben trong chya cac phan ty khi, ehu yeu Id methan (CH4) cac Idp sa Idng hydrat metan d day bien cd cho
CO be day den vai tram met Vi ehi ed the ton tai trong nhung dieu kien nhiet dp (thap) va dp suat (cao) nhat dinh nen hydrat metan chi dupe tim thay d nhijng vung bien cd dp sau nude tren 400
- 500 met (dp suat cao va nhiet dp thap) hodc d ede vung bien can hdn gan cac eye eua trai dat (d eac vung nay ap suat thap hdn nhung nhiet dp cung thap hdn) Ve tru lupng hydrat metan ed nhieu dy bao khac nhau, tuy nhien, eac tac gia khao sat deu thdng nhat vdi nhau Id het sye Idn
Dy bao gan day (2004) dua ra con sd tir 1 den 5
X 105 met khdi Con sd nay xap xi tru lupng tat ca eac nhien lieu hda thach cong lai (than, dau, khi") Theo ban dd phan bd thi day bien d rat nhieu vung vdi dp sdu tren 500 met nude va d cac vung cue cd chda hydrat metan vdi dien tich vd dp day khdc nhau (xem hinh 1),
Cho den nay chua cd nudc nao khai thde hydrat metan d quy md edng nghiep, tuy nhien, then vpng eua viec khai thde no trong thdi gian tdi Id khong nhd Nhat Ban, theo thdng bao tren
"The Time" ngdy 14/4/2008, da phat hien trd
Thdng 1 + 2 - 2009 [ J ^ J ^ ^ | 15
Trang 2lupng xac minh 39 TCF (1,1 nghin ti met khdi)
khi metan trong ede via hydrat dudi day bien TrU
lupng dy bdo la khoang 7,5 nghin ti met khdi Vdi
tru lupng tren 3 TCF, nude Nhat cd the sd dung
trong 14 nam md khong phai nhap kha'u khi
thien nhien hda Idng LNG (mdi nam Nhat nhap
khoang 62 trieu tan LNG) Dy dinh nam 2016 dy
an khai thae thuong mai hydrat metan se bit
dau trien khai cac qudc gia Trung Qudc, Han
Qudc, Canada cung dd thdng bao tim thay cac
via hydrat metan d them luc d|a Ndm 2006
Trung Qudc quyet dinh chi 100 trieu USD cho
c a c d y a n hydrat methan Hien nay ngudi ta cho
rang, phUdng phap khai thae hydrat metan kha
thi nhat la phUdng phap ha ap suat
(depressur-ization), nghTa Id lam giam ap suat de pha vd cau
true cac tinh the hydrat, do dd, khi vd nude tach
ra khdi nhau Tuy nhien, tang nhiet dp va giam
ap suat eua mdi trudng xung quanh nhat dinh se
gay ra sy pha huy cau true tinh the va khi dd khi
metan cung vdi nhung khi khac se dupe giai
phdng vdo bau khi quyen cua trai dat Khi metan
la khi doe, nhung dieu quan trpng hdn ea la kha
ndng gay hieu dng nha kinh eua no thi cao hdn
k h i C 0 2 khoang 10 Ian Nhu vay, neu khi metan
tycac Idp hydrat dupe "giai phdng" vd thoat vao
bau khi quyen thi nguy co hieu dng nha kinh la
het sye nghiem trpng
Hinh 1 Sit phan bo hydrat metan tai cac
vung bien i<hac nhau
ao hd (tao nudc ngpt) hoac ngoai bien (tao nudc man) Cd hai loai tao chinh ; dai tao (macroalgae)
va vi tao (microalgae) NhUng loai vi tao dupe chu
y nhieu vi ham lupng chat beo rat cao, dac biet la tao phu du (phytoplankton), mot loai tao don bdo, kich thudc rat nhd, khd thay dupe bang mat thudng nhung te bao dpn le nhung tdc dp sinh san eye ky nhanh, phat trien thanh tyng quan the vdi sd lupng vd cung Idn tap trung d Idp be mat nude bien (khoang hang trieu te bao trong 1 mililit) de ddn anh nang mat trdi thye hien qua trinh quang hpp Chinh tycac tao phu du chet di,
bj vui lap d day bien qua nhieu trieu nam trudc da bien ddi thanh nhung md dau cd trU lupng Idn ngoai them luc dia va dai dudng ngdy nay
Ham lupng chat beo (dau) trong tao rat cao, khoang 50% (da phan la cac axit beo khong no) trong tao khd De so sanh vdi cac loai cay ed dau khac, trong bang 1 dUdi ddy trinh bay hieu suat dau thu dupe tinh cung mot ddn vj dien tieh canh tdc vd sinh trudng
Bang 1 Hieu suat dau cua cac loai thue vat CO dau
Thye vat ed dau Ngu ede (bap) Bong vai Dau tuong Hat mu tat (mus-tanrd seed) Hudng dUOng
Hieu suat iit/ha
168
327
449
570
954
Thye vat
ed dau Hat cai (rapeseed) Jatropha curcas Dya
Cp dau Tao (algae)
Hieu suat, lit/ha 1.187 1.888 2.670 5.937 93.500
Tao (algae):
Tao Id loai thye vat bac thap, gdm mot hay
nhieu te bdo cd cau tao don gian hpp thanh,
nhung khong ed re, than va la, cd the sdng trong
Tam quan trpng cua tao trong viec san xuat nhien lieu sinh hpc hien dang thu hut sy ehu y cua nhieu nude, nhieu cong ty Vao thang 10 nam 2008, mot Hpi nghi qudc te ve sinh khdi tao (Algae Biomass Conference) dd dien ra tai Seattle, bang Washington vd chinh Bill Gates, ngay 17 thang 9 nam 2008 mdi day da edng bd dau tu 100 trieu USD cho Cong ty Sapphire Energy de da'y nhanh nghien cdu san xuat nhien lieu ty tao (algae fuel) Cong ty Sapphire Energy (My) la edng ty dang thye hien dy an xay dyng
Trang 3nha may san xuat 10.000
thung dau td tao vd dang ddn
sye giai quyet nhilmg van de ve
edng nghe de cd the trong
vdng 3-5 nam tdi dua nha may
ndy vao hoat ddng Mot
chUPng trinh nghien cdu kha thi
md hinh san xuat tao quy md
edng nghiep tri gia 2,6 trieu
Euro vdi sy hpp tdc cua nhieu
trudng Dai hpc, Vien nghien
cdu cua Phap va chau Au da
dupe tien hanh tdcudi thang 12
nam 2006 Muc tieu cua
ehuong trinh la tim va tuyen
ehpn loai tao tdi Uu ed kha
nang sinh san nhanh nhat va
cho hieu suat dau cao nhat
6 chau A, vung vinh Thai Lan
vd nam Bien Ddng dupe xem Id
VLing ed dieu kien phat trien tao
thuan Ipi vi nhiet dp ndng am
quanh ndm va giau dinh dudng,
vi vay dang cd nhieu dy an qudc
te dinh hudng vao day O nude ta,
hai loai vi tao (microalgae) ed
nhieu then vpng nudi trong la loai
Botryoeoceus braunii va
Nannochloropsis, la nhung loai
tao don bao, thich hpp vdi dieu
kien nhiet dp 20 - 23°C, cUdng dp
anh nang mat trdi 60W/m' vdi 10
-12 gid nang trong ngay va ham
lupng mudi NaCI khoang 0,15M
NhiJng loai nay deu cho ham
luong dau beo cao
Nang lupng cua sdng bien
(wave energy)
Sdng bien ngoai dai duong
la mot dang ndng lupng tai tao
do tdc dung cua gid quet tren be
mat bien; ndng lupng cua gid da
chuyen sang nang luong eua
sdng Trong khi dd, gid lai do sy
ddt ndng cua mdt trdi khong
ddng deu tren be mdt trdi dat
tao ra nen nang lupng cua sdng
bien cd ngudn gde td nang lupng mat trdi Sdng bien dupe xem nhu chat chuyen tai nang lupng mat trdi Nang lupng mat trdi truyen sang sdng bien nhieu nhat d nhung noi ed ludng gid manh nhat (khoang giua vT dp 30° va 60°) gan dudng xieh dao
Cong suat eua nang lupng sdng bien chu yeu phu thupc vao ehu ky va chieu cao cua sdng Kich thudc eua sdng phu thupc rat nhieu vao dac ti'nh eua gid (tdc dp gid, chu ky gid, hudng di eua gid), dp sdu cua bien (lam phan tan hay hpi tu nang lupng sdng), vd ddng chay eua nudc Khi cd gid to, bien dpng, chieu cao sdng cd the' len den 15m, ehu ky sdng khoang 15 giay Kich thUdc cua sdng cang Idn, cang tao ra nhieu ndng lupng, nang lupng nay d tren mat bien, hoac d dudi mat nudc bien ed the thu lai vd chuyen hod thanh dien nang nhd cac thiet bi, may mdc chuyen biet, dupe gpi la eac thiet bi chuyen ddi nang lupng sdng (wave energy converters)
Thiet bi chuyen ddi nang lupng sdng (WEC) ed kha nhieu kieu, nhung ve nguyen ly
Id phai bao gdm hai bp phan:
bp phan di chuyen (displacer) hoat dpng bang each hap thu nang lupng sdng tao ra chuyen ddng vd bp phan tao ra nang lupng mdi nhd hoat dpng cua
bp phan di chuyen, dupe gpi la reactor Mot trong nhung dang thiet bi phd bien nhat la thiet bi chuyen dd'i nang lUpng sdng kieu cot nude dao dpng OWC (Oscillating Water Columm)
Sdng di vdo vd di ra bp phan gom sdng (collector) ndm ngap
chim mdt phan dudi mat nude, tao ra mot cot nude ed the' dang len hoac ha xudng ben trong bp phan gom sdng nhd chuyen dpng cua sdng Myc nude dang len hoac ha xudng hoat ddng gidng nhu mot piston, cd tdc dung nen hoac gian khdi khong khi bi nhdt trong budng rdng cua collector, nhd dd Idm quay tude bin nude va phat dien gan
d phia tren (hinh 2 va 3)
Hinh 2 Cot nudc dao dong (OWC) de chuyen doi nang Iwong song thanh dien nang
Nang lupng cua thuy trieu (tidal energy)
Thuy trieu la hien tupng nudc bien hoac nude vung eda sdng len, xudng trong ngay Thuy trieu lien quan den sy thay ddi lye hap ddn cua vu tru ddi vdi nudc d cac thuy vyc, gdm lye hap dan giua trdi dat vdi mat trang va mat trdi Nhung dieu kien dia ly cua bien nhu hinh dang dudng bd, kich thudc hinh hpc cua bd, phan bd
dd sau, sy cd mat cac dao va vinh trong bien cd anh hudng den dd Idn vd ddc diem thuy tneu trong bien dd Thue te cho thay, bien dp dao dpng thuy trieu khi len va xudng d nhiJng
Thang 1 + 2 - 2009 Bi^n Vl^t Nam 17
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hinh 3 Thiet bi Cot nwdc dao dong
(OWC) de chuyen doi nang Iwcfng sdng
thanh dien nang
vung bien khac nhau deu khac nhau Chang han
vung vinh Fundy (Canada), bien dp dao dpng
thuy trieu rat Idn, den 18m, hoac d vung bien
nudc Anh (eda sdng Severne), bien dp dao dpng
thuy trieu la 14m, trong khi dd, vung bien Baltic
bien dp dao ddng thuy trieu la khong dang ke
Gidng nhu he thdng chuyen hda nang lupng
sdng thanh dien nang, he thdng thiet bi chuyen
hda nang lupng thuy trieu thanh dien nang cung
bao gdm hai bp phan: bd phan thu nang lupng
thuy trieu va bp phan chuyen hda nang lupng
thuy trieu thanh dien nang Tren the gidi, y tudng
chuyen nang lupng thuy trieu thanh dien nang
da ed ty rat lau vdi de an cua Thomas Fulljames
nam 1849 Rat nhieu de an dupe xay dyng sau
dd, nhung vi xay dyng nhd may dien thuy trieu
qua ton kem, gia thanh dien thuy trieu tinh ra rat
cao so vdi dien td nang lupng hda thach, vi the
nhieu dyan phai gae lai Sau cuoc khung hoang
nang lupng d nhung nam 70, cac dy dn ve dien
thuy trieu dupe xem xet lai va da'y manh d nhieu
nude, trong dd dang chu y nhat la dy an dien
thuy trieu ciJa Anh d eda sdng Severne de nghj
trude day da dupe sy ung hd cua chinh phu
thdng qua nam 1978 Nhieu dy dn nhd may dien
thuy trieu d Phap tren eda sdng Ranee, d
Canada tren vinh Fundy, d Nga tren vung bien
Murmansk dupe xay dyng trong vdng vdi thap ky
gan day Tiem nang dien thuy trieu tren the gidi
rat Idn, khoang tren 300.000 ti Wh/nam Nhung
nudc cd tiem nang phat trien dien thuy trieu la Nga, Canada, My, Argentina, Phap, Trung Qudc
va An Dp 0 nhung nude nay cd nhieu vung bien
dp dao dpng eua thijy trieu Idn, vi vay ddnh gia tiem nang dien thuy trieu chu yeu dya vao thdng
sd nay
De chuyen hda nang lupng thuy trieu thanh dien nang, thudng phai xay dyng cac dap chan d eda sdng nhung vung ed bien dp dao dpng thuy trieu Idn nhat, sd dung the ndng (potentiel ener-gy) CLia thuy trieu khi d mdc thap nhat va cao nhat trong ngay (tidal barrage) chuyen thanh dpng ndng lam quay tude bin may phat dien San xuat dien tynang lupng thuy trieu theo edng nghe nay rat gan vdi san xuat dien d cac nha may thuy dien, chi khac la nudc cd the chay theo hai hudng, luc thuy trieu len hoac luc thuy trieu xudng Khi thuy trieu len, cac eda edng tren dap
6\jgc keo len, cho phep vung luu vyc ben trong
dap ngap day nude Khi thuy trieu xudng, cac eda dap dupe ddng lai, bupe nudc ben trong dap thoat ra ngoai bien di qua he thdng tude bin nudc gan d ben dudi eda dap He thdng hoat dpng nhu tren gpi la he thdng thuy trieu xudng (hinh 4) Tuy nhien, cung cd he thdng hoat dpng theo kieu ngupe lai, tdc he thdng hoat ddng thuy trieu len
Sluice G4es
High Water IMaifc
Etfuary Floor
Hinh 4 He thong dap chan ci^a song de san xuat dien theo kieu thuy trieu xudng
The nang lupng td dap thuy trieu tao ra phu thupc vao chieu cao myc thuy trieu khi len cao
va xudng thap, ddng thdi phu thupc vao the tich nudc tieh ehda trong dap
O Anh Dy an nhd mdy dien thuy trieu Severne (Anh) dang dupe xay dyng vdi he thdng dap bac qua eda sdng Severne; chieu cao cua thuy trieu 0 day dat 14m, cao ddng hang thd hai tren the gidi Dap thuy trieu Severne ddi 18 km, ndi hai bd gida Cardif (xd Wales) va Brean Down (Anh) Dy an
18 Bl«n Vi^t Norn Thang U 2-2009
Trang 5nhd may dien thuy trieu Severne khi hodn thanh
se ed edng suat Idn nhat the gidi, 8.600 MW, hang
nam cd the san xuat 17 ty kWh dien nang, cung
cap 5-6% nhu cau dien cho nude Anh va xd
Wales, tuong duong vdi 3 nha may dien hat nhan
the he mdi nhat O Phap, tren sdng Ranee vung
Bretagne cung da xay dyng con dap ddi 750m
chdn ngang sdng, da lap dat 24 tude bin, tdng
edng suat dien 240 MW, cung cap san lupng dien
hang nam 600 tneu kWh cho vung Bretagne Nha
may duoc khanh thanh nam 1966, la nha may
dien thuy trieu dau tien tren the gidi Ipi dung the
nang cua mdc thuy trieu cao vd thap vd da hoat
ddng lien tuc 40 nam lien cho den nay
Nang lupng eua cac ddng hai luu (tide
stream):
Hai luu ed hau het trong ede dai duong cua
trai dat, ed the di chuyen tren dp ddi hdng ngan
kildmet va ed edng suat eye Idn Cac hai luu be
mat dUdc di chuyen bdi gid va ed xu hudng chay
theo xoan de cung chieu kim ddng hd d Bac Ban
Cau va ngupe chieu kim ddng hd d Nam Ban
Cau Cac hai luu ngam dudi sau chuyen ddng do
sy chenh lech gradient nhiet dp vd ty trpng nude
Cde hai luu di chuyen vdi mot tdc dp khac
nhau Nhung hai luu dudi mat nude ed tdc dp
cao, dat tren 1 m/s (thudng td 2-2,5 m/s) dupc Ipi
dung de lam quay tude bin phdt dien Nhi/ng
tude bin nay ve cau tao cung tUdng ty nhu tude
bin gid, nghla Id Ipi dung dpng ndng
(hydrokinet-ic) cua hai luu ngoai dai dUdng lam quay tude
bin Dieu dang luu y Id, theo cong thye tinh toan,
edng suat tude bin dudi bien Ipi dung ddng hai
luu ti le bac ba vdi tdc dp eua ddng chay
Anh Id nude tien phong trong viec trien khai y
tudng sd dung tude bin nhu tude bin gid de
chuyen hda nang lupng ddng hai luu thdnh dien
ndng Vdi sy hd trp cua Scottish Nuclear va NEL,
ndm 1994, IT Power da thy nghiem va xay dyng
mot nguyen mau nhd tude bin loai 2 canh, edng
suat 10 kW lap dat tai eo bien Corran Narrows
thudc vung bien Loch Line Tren cd sd thanh
cong nay, IT Power da thanh lap edng ty Marine
Current Turbines Ltd (MCT) de trien khai mdt
phien ban thiet ke mdi cua tude bin SeaGen
dupc Idp true tiep dudi ddy bien Ndm 2002,
MCT bat dau thd nghiem mot tude bin edng suat
300 kW, sau dd dd trien khai thuong mai he tude bin 600 kW va Idn hon nham tien tdi xay dyng mdt lang tude bin dudi day bien (turbine farm) vdi cong suat tdng edng 10 MW Dudi ddy la hinh anh he thdng san xuat dien thuy trieu bang tude bin dudi bien thuong mai dau tien tren the gidi SeaGen cong suat 1,2 MW nang 1.000 tan, dupc lap dat nam 2008 tai Strangford Lough (Bac Ireland) Tude bin SeaGen cd 2 rotor, dudng kinh ednh quat 16 m, tdc dp quay 10-20 vdng/phut, dupe dat sau dudi ddy bien 400m do edng ty Marine Current Turbines Ltd che tao (hinh 5) Theo dy kien, den nam 2010 se san xuat khoang 300 tude bin hang nam
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Hinh 5 Rotor cua tude bin dudi bien SeaGen che tao tai Nha may Harland and Wolff cd dudng kinh 16m tru'dc khi lap dat dudi bien Ireland
cac tude bin dudi bien de chuyen hda nang luong dOng thuy trieu thanh nang lupng dien do Anh nghien cdu va che tao da khang dinh ve cac tinh nang ky thuat - kinh te nen da dupc trien khai ra nhieu nude Cac edng ty eua Na Uy nhu Statoil va ABB da dupc edng ty Manne Current Turbine Ltd Idp dat he tude bin thuy trieu dudi day bien gan Kvalsund tai mom vung Bac eye cua NaUy Cong suat ban dau la 300 kW, khi hoan thanh day du se cd 20 he tude bin nhu vay
de san xuat dien
Cac ngudn ndng lupng ke tren, trd hydrat metan, deu Id nhung ngudn ndng lupng tdi tao,
se dUdc sy dung vinh cyu vdi quy md ngdy edng tang •
Thang 1 + 2 - 2009 Bi«n Vi^t Nam 19