The Indefinite Article

Research at Oxford shows how renewables can plug Britain's energy gap, says Oliver Tickell

For years, nuclear power has looked expensive, dangerous and dirty. That opinion may be about to change. Britain is facing a power gap of up to 2,000 megawatts (MW) of generating capacity — almost 40% of peak national demand — by 2020 as ageing, unreliable and inefficient nuclear and coal-fired power stations are shut. There is a growing consensus that only new nuclear power can plug that gap without contributing to global warming.

Renewable electricity technologies that harness wind, wave, tide and sun are all very well, the thinking goes, but their output is too variable and unpredictable to provide more than a small part of our electricity needs. Meeting the government's target of 20% renewables by 2020 could mean getting as much as 15% from wind and other intermittent sources, with the balance coming from "firm" renewables such as biomass and landfill gas. And that, say critics of renewables, is as much intermittency as the system can take. Any more and we will need huge reserves of expensive, polluting backup capacity, ready to cut in whenever the wind stops blowing.

Convinced? Think again. Research at Oxford University shows that intermittent renewables, combined with domestic combined heat and power (dCHP) could dependably provide the bulk of Britain's electricity. "By mixing between sites and mixing technologies, you can markedly reduce the variability of electricity supplied by renewables," says Graham Sinden, of Oxford's Environmental Change Institute. "And if you plan the right mix, renewable and intermittent technologies can even be made to match real-time electricity demand patterns. This reduces the need for backup, and makes renewables a serious alternative to conventional power sources." In particular, it puts renewables ahead of nuclear power, which runs at the same rate all the time regardless of fluctuations in demand.

Sinden initially looked at just three generation technologies: wind, solar and dCHP — in effect, hi-tech domestic boilers, which produce electricity as they heat water. He ran computer models of power output based on weather records going back up to 35 years, and found that electricity production could be optimised by creating a mixture of 65% wind, 25% dCHP, and 10% solar cells. The high proportion of wind is because the wind blows hardest in the winter, and in the evening — when demand is highest. The dCHP also produces more at peak times, when demand for hot water and heating is also strongest. Solar makes a smaller contribution, and produces nothing at night. But it is still important to have it in the mix as it kicks in when wind and dCHP production is lowest.

It is also essential to disperse the generators, whether wind turbines or rooftop solar cells, as widely as possible. By increasing the separation between sites, you can be sure that power is always being generated somewhere and so smooth out the supply curve. This goes against current practice, which is to put wind turbines where the wind is strongest.

Sinden's approach is remarkably effective in reducing the need for standby capacity. If offshore wind power alone were to provide an average 3,500MW of electricity — 10% of electricity demand in England and Wales — it would need to be backed up by an extra standby generating capacity of 3,135MW — 90% of average production. But using Sinden's proposed mix of technologies, only 400MW of new standby capacity would be needed — just 11%.

In his latest work, commissioned by the Carbon Trust, Sinden has been researching the roles for wave and tidal power. Wave power output is concentrated into autumn and winter, when demand is greatest: 75% of wave power is produced between October and March. Tidal power output is predictable, but variable: at any site it drops to zero four times a day on the turn of the tide; and output is three or four times greater on the spring tide than on the neap tide. "A marine-based renewable system works best when it includes both tide and wave," says Sinden. "The combination has lower variability, is better at meeting demand patterns, and makes better use of expensive transmission infrastructure."

Putting these figures together with estimates of Britain's available renewable resources, wind (onshore and offshore) could realistically provide some 35% of the UK's electricity, marine and dCHP each 10-15%, and solar cells 5-10%. In other words, more than half the UK's electricity could ultimately derive from intermittent renewables.

"In the next year or so, the UK is going to have to decide how to meet its electricity needs for the next half-century," says Sinden. "It's an incredible opportunity for renewables but my fear is that it may be missed."

The Indefinite Article

1.	One noun in general, and it does not matter which one
2.	the very first time mentioned – the indefinite article; the second time mentioned – the definite article
3.	Professions
4.	Beliefs
5.	Per
I have two cars: a Ford and an Audi. The Ford is white and the Audi is silver.
He drove at 60 miles an hour.
Can you lend me a pen please?
He is a Buddhist and his wife is an atheist.
She is an architect and he is a doctor.

the The Definite Article

1.	One specific example of the group
2.	It is clear which thing we mean
3.	Services of a country of city
4.	The very first time mentioned – the indefinite article, the second time mentioned – the definite article
5.	Unique things
6.	Families
7.	Superlative adjectives
8.	Parts of day
9.	Ordinal numbers
10.	Inventions
11.	Oceans, seas, rivers, canals, channels, bays, gulfs
The Pacific, the Mediterranean, the Amazon, etc.
The captain was the first person to leave the burning tanker.
The door, the ceiling, the floor, the carpet, the light, the roof, the garden, the kitchen, the bathroom, the toilet, the centre, the station, the airport, the town hall, the bank, the post office, at the top, at the bottom, in the middle, on the right, on the left, on the coast, on the boarder.
The police, the army, the fire brigade
In the morning, in the afternoon, in the evening
The Simpsons, The Smiths
The computer has changed our lives.
The cat with the gray and black coat is mine.
I have two cars: a Ford and an Audi. The Ford is white and the Audi is silver.
The sun, the moon, the sea, the sky, the Arctic Circle, the environment, the capital, the air, the ground, etc.
It was the worst day of my life!
1.	Island and mountain chains
2.	Deserts
3.	Countries with plural names and of unions
4.	Points of the compass
5.	Titles
6.	Proper names consisting of noun(s) and/or adjective(s) + noun.
7.	Hotel names
8.	Newspapers
9.	The same
10.	Currencies
11.	Names of musical instruments
12.	Many forms of entertainment (e.g. the cinema, the movies, the theatre, the circus, the ballet, the opera and the radio), but not the medium of television.
The North, The South, The East, The West, The Far East, etc.
The West Indies, the Rockies, etc.
The Sahara, etc.
The Queen of Denmark
The United States, the United Kingdom, The United Arab Emirates, the Netherlands, The Hague, etc.
The English Channel, the White House, the Rolling Stones, the Berlin Philharmonic Orchestra, the British Museum, etc.
The U.S. dollar has risen against the yen but fallen against the euro.
The Hilton Hotel, the Savoy, the Sheraton
Richard Clayderman plays the piano.
The Times, the Baltimore Sun, the Daily Mail
I go to the cinema/movies, the theatre, the circus, the ballet and the opera. I often listen to the radio and sometimes I watch TV.
Your pullover is the same colour as mine.

The Zero Article

1.	Abstract nouns used in a general sense
2.	Name of a person
3.	Names of a continents, countries, cities
4.	Names of lakes
5.	Names of a place
6.	Seasons, months and days
7.	Parts of day/night
8.	Company names
9.	Roads, streets, parks, squares or bridges
10.	Names of islands
11.	Names of single mountains, hills
12.	Magazines
13.	Names of meals, unless it is a formal occasion
14.	Names of games or sports
15.	An institution: bed, church, court, hospital, prison, school, college, class, home, market, work university. However, if they are buildings or particular places, the is required
16.	Television as a medium, only as an appliance the is used.
17.	Noun followed by a categorizing letter or number.
Love is all you need. Crime is a growing problem in the inner cities.
Winter, February, Monday, Tuesday
Harrods, Macys, McDonald's
Midnight, midday, noon, night
Africa, Asia, Thailand, Argentina, Madrid, Bangkok
Microsoft, Hitachi, Lufthansa, etc
Lake Como, Lake Svityaz’
Queen's Road, Oxford Street, Central Park, Times Square, Tower Bridge, etc.
St. Paul's Cathedral, Kennedy Airport, Cambridge University, etc.
Anna Kournikova plays tennis to keep in shape.
Easter Island
She stayed in bed on Sunday instead of going to church. He entered the church to photograph its interior.
While in New Zealand I climbed Mount Cook.
Carol saw her brother on television. She had an indoor antenna on the television
Roger had breakfast in his hotel room.
The students have just read section C. She is staying in room 689.
Cosmopolitan, Time, Pink

Date: 2014-12-29; view: 1002

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