Kelių savaičių the Economist straipsnis (žr. žemiau) apie vėjo energiją (tekstas žemiau) ir naujas įrašas Master Resource blog‘e vėjo energetiką globalinio atšilimo argumentų fone sukritikuoja iš beveik visų įmanomų pusių.
Economist turbūt niekas nedrįstų apkaltinti „skepticizmu” globalinio atšilimo tema. Tačiau vėjo energija neapsimoka net ir tikint globaliniu atšilimu. Anot the Economist, siekiant CO2 emisijų sumažinimo žymiai tikslingiau yra ne subsidijuoti vėjo energiją, o pirkti CO2 emisijas rinkoje.
Tuo tarpu Master Resource vėjo energetiką kritikuoja gana fundamentaliai. Vėjo energija yra palyginama su girtu vairuotoju – neprognozuojama, sporadiška ir brangiai kainuojanti padaryti ją saugia.
Kuo šie straipsniai įdomūs ir naudingi – tai sveika ir pagrįsta analize. Kitaip tariant, galima tikėti ar netikėti globaliniu atšilimu, bet pagrįstus argumentus atremti yra sunku.
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Oil rigs to whirligigs
New plans to increase clean power are ambitious and expensive
Jan 14th 2010
From The Economist print edition
THE diameter of a wind turbine capable of generating five megawatts (MW) of electricity is, at 120 metres, roughly that of the London Eye. If it is to be installed in seas 40 metres deep, its pylon and foundations must measure 170 metres or so, half again as high as St Paul’s Cathedral. If it is to stand in the North Sea, it will confront waves that can rise more than ten metres high and winds that can reach over 100 kilometres an hour. And if it is to be part of plans to increase the proportion of electricity generated from renewable sources to something like 30% by 2020 (it is currently 5.5%), it will be one among thousands.
On January 8th the Crown Estate, which administers the seabed around Britain, revealed the preferred bidders for the nine areas seen as suitable for a third round of offshore wind power. These sites could house turbines with a combined capacity of over 30 gigawatts (GW, or 30,000MW), though average energy production would be at best only about a third of that. The largest of the sites, Dogger Bank, is calculated to offer 9GW—six times the worldwide installed base of offshore wind generating capacity in 2009.
That base is growing fast, almost entirely in Europe. The European Wind Energy Association says that just under 200 turbines were installed and attached to electricity grids in European waters in 2009; it puts the capacity currently under construction, almost half of it in British waters, at 3.5gW. Round 3, which requires up to £100 billion of capital expenditure, brings European plans for offshore wind to more than 100GW and would see Britain the largest player (see chart).
The level of ambition is exceptional, if not unprecedented. In the ten years from 1965, Britain’s Central Electricity Generating Board installed 28GW of new power stations. The “dash for gas” in the early 1990s produced 26GW of capacity. Neither was as large an investment as Round 3, but capital expenditure on North Sea oil over the decade from 1975 was on a similar £100 billion scale, in today’s money.
Engineering firms and suppliers that cut their teeth on the rigs built back then are keen to transfer their know-how to today’s challenge. Innovation is vital: the typical deployment rate for today’s smaller turbines has been one every ten days or so, but to deliver Round 3 by the early 2020s requires building up to an average of more than two deployments a day. While the turbines themselves will be fairly standard (if gargantuan), the structures that hold the things up and the techniques to erect them must be improved. An “offshore wind accelerator” programme run by five offshore wind companies and the Carbon Trust, a government-created non-profit organisation, is looking at ways to reduce capital and operating costs, including turbines that stick to the sea floor with suction rather than deep foundations and are thus much easier to put in place.
This sort of research and development could knock almost 20% off the total cost of wind farms far from shore, says Benjamin Sykes of the Carbon Trust (himself a refugee from offshore oil). Just as well: in the past few years the cost of offshore wind has been rising, due to a snarled supply chain and the fall in sterling—a fall which, along with increased demand, could now lure foreign firms to build turbine factories in Britain.
There is, though, a vital difference between this century’s offshore engineering and last century’s. North Sea oil made money. North Sea wind costs money: the offshore industry depends entirely on subsidy. In Britain this is provided through a mechanism called the Renewables Obligation, which requires those who sell electricity to buy an increasing amount of it from renewable sources.
For offshore wind, the obligation currently adds about £90 to the £50 cost of a megawatt-hour of energy. If the alternative to offshore wind is assumed to be natural gas, the subsidy is about £180 for every tonne of carbon dioxide not emitted. That is well over ten times the cost of a tonne of the stuff in the European emissions-trading system. And, as Dieter Helm of Oxford University points out, the subsidies may not actually cut world emissions. As electricity prices in Britain rise to accommodate the subsidy, the chances of industry moving to lower-cost, higher-carbon economies elsewhere rise with them.
Under current legislation, the Renewables Obligation will peak at 15.4% in 2015, which is too low to support Round 3. The government has said that it would like to extend it, and has increased the payments made to offshore wind in the meantime. If the support system is increased enough to deliver 29GW of offshore wind, according to the Carbon Trust it would have to pay out around £60 billion in current terms, maybe more—perhaps twice the cost of the nuclear capacity required to generate the same amount of electricity. You can add to the awe-inspiring engineering achievements of the offshore wind industry an unparalleled ability to make nuclear power look cheap.
