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Unlock This CourseA country with an energy deficit has two choices. It can increase supply, or it can manage supply and demand so that it needs less. Most countries do both. In the last two lessons you weighed up each energy source. Now you look at the action plans (strategies) and the methods (techniques) that governments and companies use.
Key terms:
Companies explore for new reserves of oil and gas. They drill offshore under the seabed, in the Arctic as the ice retreats, and use fracking to release gas and oil trapped in shale rock.
Strength: uses existing technology, pipelines and refineries, and can add a large supply. Weakness: expensive and risky in deep or icy seas, a spill is hard to clean up in the Arctic, and burning more fossil fuels adds to climate change.
Governments and companies build more nuclear power stations and more renewable capacity such as wind farms, solar farms and HEP dams.
Strength: low carbon and a long-term supply. Weakness: very high building costs, and it takes years to plan and build. Wind and solar are intermittent.
A country can buy energy from abroad. Oil comes by tanker, and gas comes by pipeline or as a liquid in ships. Electricity can also be bought through cables from neighbouring countries.
Strength: fast, and needs no local reserves. Weakness: prices can rise, and supply can be cut by conflict or disagreement, which weakens energy security.
A smart grid wastes less power and can balance many small producers. Battery storage keeps spare wind and solar power for when the wind drops or night falls.
Strength: makes intermittent sources far more useful. Weakness: costly to install, and the batteries need raw materials that must be mined.
Instead of making more energy, these approaches reduce how much is needed. Many are cheaper than building a new power station, because the cheapest energy is the energy you never use.
| Approach | How it works | Strength | Weakness |
|---|---|---|---|
| Insulation | Loft and wall insulation keep heat in, so less fuel is burned for heating. | Saves money every year and cuts carbon dioxide. | Costs money up front, and older homes are harder to fit. |
| LED lighting | LED bulbs give the same light using far less electricity than old bulbs. | Cheap, easy and quick to fit. | Savings are small compared with total demand. |
| Efficient vehicles | Cars and lorries use less fuel per kilometre. Electric vehicles are very efficient. | Cuts oil use and local air pollution. | New vehicles are expensive, and many people cannot afford them. |
| Reducing demand | Public campaigns, better public transport and cycling lanes persuade people to use less. | Costs little and cuts demand quickly. | Relies on people changing habits, and economic growth pushes demand up. |
| Carbon taxes and targets | Taxing carbon makes fossil fuels dearer, and targets set a limit for emissions. | Raises money and rewards cleaner choices. | Unpopular because bills rise, and poorer people are hit hardest. |
| Renewable subsidies | Payments or tax breaks make wind, solar and other renewables cheaper to build or buy. | Speeds up the move to low carbon energy. | Costs governments money, and it only works while the money lasts. |
| Diversifying the energy mix | Using many sources, including some home-grown ones, spreads the risk. | One failed source does not cause a crisis. | Needs investment in several types of infrastructure at once. |
| International agreements | Countries promise joint targets or share technology. See Managing Climate Change: Agreements and Techniques. | Action spread across many countries is more effective. | Hard to enforce, and some countries do not take part. |
Energy supply is sustainable when it meets today's needs without harming the environment or stopping future generations from meeting theirs. It must be affordable, secure and low in carbon. Conservation and efficiency are usually the most sustainable choices, because they need no new fuel at all. A new Arctic oil field is the least sustainable.
Examiners want you to weigh up, not just list. Ask these questions about any strategy:
A sensible judgement is usually "a mix". Efficiency cuts demand cheaply, new renewables and storage provide clean supply, and imports or new reserves cover the gap in the short term.
Made-up Country V plans two measures. Measure A is wind farm building: cost US$900 million, supply added 600 GWh a year. Measure B is home insulation: cost US$300 million, energy saved 450 GWh a year. Cost for each GWh is cost divided by GWh. A: 900 ÷ 600 = US$1.5 million. B: 300 ÷ 450 = about US$0.67 million. Insulation gives each GWh at less than half the cost, but wind adds more energy in total and helps with carbon too. A good judgement says use both.
Writing only advantages. Saying "renewables are better" without any reason. Forgetting that managing demand is also a way to close an energy gap. Confusing conservation (using less) with efficiency (using less to do the same job). Writing a judgement that does not say who benefits or how sustainable it is.
Table 1 shows made-up data for three measures in Country W.
| Measure | Cost (US$ million) | Energy saved a year (GWh) |
|---|---|---|
| Home insulation | 200 | 400 |
| LED street lighting | 50 | 250 |
| Smart thermostats | 100 | 150 |
(a) Identify the measure that saves the most energy. [1]
(b) Calculate the cost for each GWh saved by LED street lighting. [2]
(c) Explain two ways that a country can increase its energy supply. [4]
(d) Evaluate the strategies a country can use to manage its energy supplies. [6]
(a) Home insulation (400 GWh). (1)
(b) 50 ÷ 250 (1) = US$0.2 million for each GWh, or US$200,000. (1)
(c) Any two, each with an explanation: build more nuclear or renewable capacity (1), which gives low carbon power for many years (1). Import energy by pipeline or tanker (1), which is quick but leaves the country relying on other countries (1).
(d) Level 3 (5-6 marks): Strategies such as insulation, LED lighting and efficient vehicles cut demand and are usually cheap. They are very sustainable, as they need no extra fuel. Their weakness is up-front cost and the fact that growth can cancel out savings. Carbon taxes and renewable subsidies push people and companies to cleaner choices, but taxes raise bills for poorer households and subsidies cost the government money. Diversifying the mix and international agreements reduce risk and spread the effort, but are slow and hard to enforce. Overall, efficiency and conservation are the best starting point because they are cheap, fast and sustainable, but they cannot meet all needs, so a mix with renewables and storage is the best judgement.
In an "Evaluate" answer, finish with a clear judgement that names the strategy you think is best and gives a reason such as cost, speed or sustainability.