Resources and environment, Year 11: supply, insecurity and sustainable use (Energy option)

Energy security

提示Two words; the second also means safety.

为什么This is the International Energy Agency's definition. A country is more secure if it produces its own energy, uses several different sources and buys from several suppliers. One that depends on a single fuel or a single supplier is energy-insecure, even if it is wealthy.

Sub-Saharan Africa

提示Lagos, Nairobi and Kinshasa are among its biggest cities.

为什么In 2023 about 750 million people had no electricity, and about 80% of them lived in sub-Saharan Africa, mostly in rural areas far from a power grid. Energy use per person is highest in North America, Europe, the Gulf states and Australia. Countries within every region differ widely.

geology

提示The study of rocks.

为什么Oil and gas are found only where the right rocks formed and trapped them millions of years ago, so reserves are very unevenly spread. Other physical factors matter too: climate decides where solar and wind power work well, and relief and rainfall decide where hydro-electric power is possible.

It makes reserves that were too difficult or too costly to reach worth extracting

提示Think of drilling deeper, further offshore or into harder rock.

为什么Whether a reserve is used depends on the cost of getting it out compared with the price it sells for. Better drilling and extraction methods lower that cost. In the same way, cheaper solar panels and larger wind turbines have turned sunshine and wind into affordable supplies.

A political factor, such as a dispute, sanctions or war

提示Think governments and borders, not rocks or prices.

为什么Energy crosses borders in pipelines, cables and tankers, so it depends on relations between governments. An exporter can restrict supply, a war can block a route and sanctions can ban a trade. Governments also shape supply at home, for example by banning or subsidising an energy source.

Reserves that are easy to reach are running down, so harder ones become worth the cost

提示The low-hanging fruit has been picked.

为什么When supply is insecure and prices are high, reserves in remote and hostile places become profitable. These are often environmentally sensitive areas: a spill is hard to clean up in icy or deep water and ecosystems there recover slowly. Extraction also costs far more, which is an economic cost of insecurity.

fuel poverty

提示The second word means being poor.

为什么When energy is scarce its price rises, and households on low incomes are hit hardest. In England a household is counted as fuel poor if its home is poorly insulated (energy rating D or below) and paying to heat it would leave the household below the poverty line.

Farmland and crops are used for fuel instead of for food

提示A field can only grow one harvest at a time.

为什么Biofuels are one answer to energy insecurity, but they compete with food for land and water, which can push food prices up. Farming also depends on energy for tractors, pumps and fertiliser, so dearer energy means dearer food.

Production costs rise, so factories cut output or close

提示Look at a manufacturer's monthly bills.

为什么Industries such as steel, cement, glass and chemicals use very large amounts of energy. When energy is short or dear, they produce less, lay off workers or move abroad. Power cuts have the same effect: machines stand idle.

pipelines

提示Long steel tubes laid across land or seabed.

为什么Most oil and gas is used far from where it is extracted, so supplies pass through other countries and narrow sea routes. A country that controls a field or a route has power over those that depend on it. Disputes can be political, economic or, at worst, military.

tidal; wave

提示One is driven by the Moon's pull, the other by wind over the ocean.

为什么The seven renewable sources are biomass, wind, hydro, tidal, geothermal, wave and solar. The non-renewable ones are the fossil fuels (coal, oil and gas) and nuclear power. Increasing supply means developing more of either group, and each choice has costs.

New plants must be grown to replace those that are burned

提示Think of a forester with a spade and a sack of seedlings.

为什么Biomass is plant or animal material used as fuel: wood, crop waste, dung or crops grown for fuel. The new growth takes in carbon dioxide as it grows. If forest is cut and not replaced, biomass is neither renewable nor low-carbon.

Iceland lies on a plate margin, where hot rock is close to the surface

提示Think of volcanoes and the map of the Earth's crust.

为什么Geothermal power needs heat near the surface, which is found mainly along plate margins and at volcanic hot spots. This shows how physical geography limits each source: hydro needs relief and rainfall, solar needs strong sunshine and tidal needs a large tidal range.

It relies less on imports, which can be cut off or rise in price

提示Think who else has a hand on the supply.

为什么This is the main advantage claimed for extracting a fossil fuel, together with jobs, tax income and export earnings. The disadvantages are environmental: damage to land and water at the site, the risk of spills and leaks, and the carbon dioxide released when the fuel is burned.

The fuel is finite: when it runs out, the jobs and income go

提示Mining towns have learned this the hard way.

为什么A fossil fuel reserve is used up once. While it lasts it can pay for roads, schools and services, but a region that depends on it faces unemployment when extraction ends. Whether the income was invested for the future is a fair question to ask of any example.

Energy demand reduction

提示Supply is one side of the balance; this works on the other.

为什么Demand can be cut by price (charging more at busy times), by information (smart meters, energy labels on appliances), by rules (building standards) and by incentives such as grants for insulation. Energy that is not used costs nothing and causes no emissions.

Combined heat and power (CHP)

提示Two useful outputs from one lot of burned gas.

为什么An ordinary power station throws away much of the energy in its fuel as waste heat. Capturing that heat for homes, hospitals or factories gets more use from the same fuel. It is an example of technology that increases efficiency in the use of fossil fuels.

smart meter

提示The first word also describes a modern phone.

为什么Seeing the cost as it happens helps people notice waste and change habits, which is a form of energy conservation. Homes can also be designed to use less: insulation, double glazing, efficient boilers or heat pumps, LED lighting and solar panels on the roof.

They use far more energy and goods, mostly supplied by burning fossil fuels

提示Think of cars, flights, heating and shopping.

为什么A carbon footprint is the total greenhouse gas emissions caused by a person, product or activity. Wealthier people travel more, live in larger heated or cooled homes and buy more manufactured goods. An individual can shrink a footprint by using less energy, travelling differently and wasting less.

Running power lines a long way to a few users is very costly; a local scheme is cheaper and the community can run it

提示Count the kilometres of cable against the number of customers.

为什么A local renewable scheme uses a free local resource, such as sunshine or a stream, and has low running costs. Light in the evening lets children study and businesses open longer, and it replaces kerosene lamps and their smoke. When you write about your own example, show its social, economic and environmental benefits.