Cloze Passage: Geothermal Energy

Geothermal electricity: The next hot thing?


By Michael Richardson, For The Straits Times

CLOZE PASSAGE

Text Type: Information Report

Grammar Focus: Subject Verb Agreement, Tenses, Prepositions

Straits Times 12 Oct 2009

Fill in the blanks Also, underline the correct word in the brackets.

ENVIRONMENTAL activists have an above-ground and a below-ground view of the world.

Helping words

Greenhouse proliferation energy activity harnessed warming pollution

Fire power plates development heat gas found fuel hotter surface

Temperature days earth

Energy sources 1. _______________ on or very close to the surface, such as wind, tidal, solar and hydro power, are good. These sources are renewable and do not emit carbon dioxide, the main greenhouse gas A. (warmed/ warmer/ warming) the planet.

However, energy sources found B. (in/on/under) the ground - such as coal, oil and natural gas, as well as uranium for nuclear power – C. (are/were/is) bad. Fossil fuels are major 2. _____________ gas emitters while nuclear power, though it D.(produced/produce/produces) almost no global 3. _____________ emissions, is still regarded by many environmentalists as too much of a safety and 4. ____________ risk.

But there is another form of underground energy that E.(get/got/gets) an environmental seal of approval: geothermal heat. What F. (come/came/comes) out of the ground with this form of energy are hot water and steam, and almost no 5. ___________.

Advocates point out that geothermal is the only form of renewable 6. ____________ that provides a near-constant supply of base- load electricity to commercial grids in the same way that plants G. (powering/power/powered) by coal, oil, gas and nuclear fuel do. Other types of renewable energy generate electricity intermittently, depending on the strength of the sun, wind, waves and tides.

South-east Asia is a world leader in exploiting the first wave of geothermal 7. __________, although it could do even more with the right incentives. Of some 10,000 MW of geothermal power installed around the world, nearly one-third is in the Philippines and Indonesia, the two largest generators of electricity using underground heat, after the United States.

This is only a tiny fraction of global electricity supply. But installed geothermal capacity is expected to reach 13,500 MW next year, with the number of countries producing power from underground heat rising to 46, from 21 a decade ago.

This power system is currently limited to areas where volcanic 8. ________ produces very hot underground water in reservoirs, which may be as large as 50 sq km and H. (could/ was/can) be tapped to drive steam turbines installed in power plants on the surface.

Among places with the richest volcanic resources are those on the so-called Ring of 9. ____________ that circles the Pacific. They include New Zealand, Indonesia, the Philippines, Japan, Russia's Kamchatka Peninsula, the west coasts of the US and Canada, Central America, and the west coast of South America.

The Ring of Fire is a zone where tectonic 10. ____________ collide to create the earthquakes and tsunamis so much in the news in recent 11. ______________. But these same forces also I. (create/ created/ have created) subterranean heat reservoirs that can easily be reached with current oil and 12. __________ drilling technology.

But volcanic geothermal power exploits less than 5 per cent of the very hot underground water resources that could be exploited worldwide, according to the International Energy Agency. Advanced drilling technology in geologically stable parts of the world J. (has opened / is open / was opened) up a big underground 13. ____________ source for future power generation. This K. (had unleashed/ was unleashed/has unleashed) a wave of exploration and 14. ___________ activity in Australia, Europe, the US, China and India.

Known as Enhanced Geothermal System (EGS) or 'hot rock' technology, it focuses on high heat-producing granite typically 15. ___________ between 3km and 5km below the 16. __________. In this zone, which draws heat from the molten core of the earth and the decay of radioactive elements in the crust, the 17. ___________ can reach 300 deg C. By some calculations, the heat energy content in the upper 10 km of the earth's crust is 50,000 times greater than the energy content of all known oil and gas resources.

Exploiting this power - by drilling down, fracturing the rock with water pumped in under high pressure and then drawing very hot water from the resultant reservoir up a separate well - poses major technical and financial challenges. Since 2006, two EGS projects in Europe, both near urban centres, L. (have been halted/ halted/ was halted) amid concerns that the underground rock fracturing had caused 18. __________ tremors. However, this appears to be a manageable problem.

Geoscience Australia, a government agency, calculates that extracting just 1 per cent of the energy from rocks 19. ____________ than 150 deg C (the minimum for generating electricity) and less than 5 km below the surface would yield about 26,000 times Australia's primary power usage in 2005.

A report last year commissioned by the Australian Geothermal Energy Association concluded that geothermal power could provide 2,200 MW of baseload capacity by 2020, about a third of the new generating capacity the country would likely need by then.

But this will require investment of at least A$12 billion (S$15 billion). The cost of geothermal electricity will also M. (have/ had/ has) to fall. The industry reckons this will happen as commercial-scale generation results in improved efficiency and climate change concerns impose added costs on fossil 20. ____________ power.

The writer is a visiting senior research fellow at the Institute of Southeast Asian Studies.

Answers

Fill in the blanks

1. harnessed 2. greenhouse 3. warning 4. proflieration 5. pollution

6. energy 7. power 8. activity 9. Fire 10. plates 11. days 12. gas

13. heat 14. development 15. found 16. surface 17. temperature

18. earth 19. hotter 20. fuel
Underline the correct word in the brackets.

A. warming B. under C. are D. produces E. gets F. comes

G. powered H. can I. create J. has opened K. has unleashed

L. have been halted M. have