Energy » Sustainable Energy

Moving towards a sustainable energy future

Fossil fuels will not last for ever, and burning them adds to climate change. A sustainable energy future means meeting today's energy needs without harming the environment or running out of energy for people in the future.

There are two big ways to get there. We can make energy from renewable sources (you met these in the lesson on increasing energy supply). We can also use less energy, and use it more wisely. This lesson is about using energy wisely, and about one renewable scheme that works at a local scale.

Key terms:

• Sustainable energy future: getting enough energy for everyone now and later, without damaging the environment.
• Demand reduction: using less energy in the first place.
• Energy efficiency: getting the same job done using less energy.
• Micro-hydro scheme: a small hydroelectric scheme that uses a stream or small river to make electricity for a local community, with no large dam.

Individual energy use and carbon footprints

Every one of us uses energy. We use it at home for light, heating and cooking, and we use it to travel. Most of it still comes from burning fossil fuels, which releases carbon dioxide.

Remember, a carbon footprint is the amount of carbon dioxide released by a person's activities. Your individual energy use is a large part of your carbon footprint. The more energy you use from fossil fuels, the bigger your footprint.

Individuals matter because a country's energy demand is the total of millions of people's choices. If many people cut their use a little, demand falls a lot.

Energy conservation

Energy conservation means saving energy and cutting waste. The spec lists three places where this can be built into design, plus demand reduction and efficiency.

Designing homes for sustainability

• Loft and wall insulation and double or triple glazing keep heat in, so less heating is needed.
• Solar panels on the roof make electricity or hot water from sunlight.
• Large windows facing the Sun let in free heat and light.
• Energy-efficient appliances and LED bulbs do the same job for much less power.

Designing workplaces for sustainability

• Good insulation and smart heating controls that switch off when nobody is there.
• Motion sensors so lights only come on when rooms are in use.
• Making the most of daylight with large windows and skylights.
• Encouraging staff to cycle or use public transport and to work from home when they can.

Designing transport for sustainability

• Good public transport, such as trains, trams and buses, moves many people using less energy per person than cars.
• Cycle lanes and safe footpaths make walking and cycling easier.
• Electric vehicles use no petrol or diesel. They are cleaner when the electricity comes from renewable sources.
• Car sharing means fewer cars on the road for the same number of people.

Demand reduction and efficient use of fossil fuels

Demand reduction means we need less energy in the first place. Examples are switching things off, turning heating down a little, and buying products that are built to use less energy. It is the cheapest form of "new" energy, because the energy never has to be produced.

Fossil fuels will still be used for some time, so the spec also asks for technology to increase efficiency in the use of fossil fuels. This means wasting less of the energy in each tonne of fuel. For example:

• Modern gas power stations can be built to capture and use waste heat as well as electricity.
• More efficient engines let cars travel further on each litre of fuel.
• Condensing boilers capture more heat from burning gas, so homes need less gas for the same warmth.

Using fossil fuels more efficiently means the supply lasts longer and less carbon dioxide is released.

A local renewable energy scheme: Chambamontera, Peru

Peru is a newly emerging economy (NEE), though remote Andean villages such as Chambamontera still have very low incomes. The village of Chambamontera is in the Andes mountains, in northern Peru. It is a remote community, more than two hours by rough track from the nearest town, Jaen. The national grid does not reach it.

The total cost was about US$51,000. Money came from the government, from Japan and from the community itself. Families paid an average of about US$750 each, and credit was available to help them pay.

Why is it sustainable?

• Social: better lighting lets children study after dark, makes it safer to move around at night, and allows medicines to be kept in a fridge.
• Economic: machinery can be run, for example to process coffee, so people can start or grow businesses. This helps young people stay rather than move to cities.
• Environmental: it is renewable, has a small footprint and needs little maintenance. Less wood and kerosene are burned, so there is less deforestation and soil erosion.

The scheme is small, local and run by the community, so it can be repaired and kept going by local people. That is why it is a good example of appropriate, sustainable energy for an LIC or NEE.

Exam-style question

(a) Give two ways a household can reduce its energy use. [2 marks]

(b) Describe how technology can increase the efficiency of fossil fuel use. [2 marks]

(c) Explain how the micro-hydro scheme at Chambamontera, Peru has provided sustainable energy for the local community. [4 marks]