2.11 - Energy Resources Introduction

Non-renewable resources will run out one day

• A non-renewable energy resource is one that's used up faster than nature can replace it, so it will one day run out.
• The non-renewables are the fossil fuels and nuclear fuel.
• The three main fossil fuels are coal, oil, and (natural) gas. These formed underground over millions of years and are burnt to release their energy.
• The nuclear fuels are uranium and plutonium.

What they have in common

• Reliable - Power stations keep fuel in stock, so they can generate electricity whenever it's needed. Gas power stations can also respond quickly when demand increases, but nuclear power stations are slow to start up.
• Will run out - They're being used far faster than they form.
• Damage the environment - All non-renewables harm the environment.

Renewable resources will never run out

• A renewable energy resource is one that's replenished as fast as (or faster than) it's used, so it will never run out.
• The renewable energy resources are:
  • The Sun (solar)
  • Wind
  • Hydroelectricity
  • Tides
  • Biofuels

How they compare with non-renewables

• They do less harm to the environment than fossil fuels, though most still cause some damage.
• Several are less reliable, because they depend on the weather and can't always produce energy on demand.
• Many produce less energy than a fossil-fuel or nuclear power station, but they have low running costs once built.

Uses - Electricity, transport and heating

• Both renewable and non-renewable resources are mostly used to generate electricity, which can then be sent wherever it's needed.
• The two other major uses are transport and heating.

Transport

• Petrol and diesel vehicles (including most cars) use fuel made from oil.
• Many vehicles run on a mix of biofuel and petrol or diesel, or on pure biofuel.
• Electricity can power vehicles such as trains and cars, generated from either renewable or non-renewable resources.

Heating

• Natural gas is the most widely used fuel for heating UK homes - the gas heats water, which is pumped to radiators.
• Coal can be burnt in a fireplace, and burning biofuel can also heat homes.
• A geothermal heat pump uses geothermal energy to heat buildings.
• Solar water heaters use the Sun to heat water that's pumped to radiators.
• Electricity from any resource can be used for heating (e.g. in electric heaters).

In terms of energy stores

1. A fuel holds energy in its chemical energy store.
2. Burning it transfers that energy to the internal (thermal) energy store of its surroundings.
3. From there it can transfer to other useful stores, such as the kinetic energy store of a moving vehicle.

We still depend on fossil fuels but want more renewables

A country's mix of energy resources changes over time, driven by new technology, better understanding of environmental effects, and changes in cost.

How UK electricity use has changed

• Over the 20th century, UK electricity use rose sharply as the population grew and people used electricity for more things.
• Since the start of the 21st century, electricity use has been slowly falling, as appliances became more efficient and people used energy more carefully at home.
• Some electricity is still produced from fossil fuels and nuclear power; the rest comes from renewables such as wind.

Why people want more renewables

• Burning fossil fuels is damaging to the environment, so people want resources that do less harm.
• Because non-renewables will run out, countries need alternatives before fossil fuels are exhausted.
• Public and international pressure leads governments to set renewable targets, pushing energy providers to build renewable power plants.
• Electric cars and hybrids (powered by two fuels, such as petrol and electricity) are becoming more popular.

Weighing up which resource to use

• Factors when choosing a resource include: availability, cost, reliability, environmental impact, and opportunities such as jobs.
• For a power station, useful comparisons include:
  • Start-up time - How long before it begins producing energy.
  • Generating capacity - The maximum power it can produce in normal conditions.

Reliability, cost and politics limit the switch

There's strong scientific evidence supporting renewables, but scientists can only give advice - they can't force people, companies or governments to change.

Reliability

• Some renewables aren't as reliable as fossil fuels, and some can't increase output on demand.
• Switching completely would mean running a combination of different power plants or developing large-scale energy storage, both of which are expensive.

Politics

• Even when new power plants are approved, there are arguments over where to put them.
• For example, many people don't want to live near a wind farm, and there's debate over whether it's fair to build one near communities.

Cost

• Building new renewable power plants costs money, paid through energy bills or taxes, which not everyone can afford.
• Research to improve reliability and cost takes time and money. Meanwhile, dependable non-renewable power stations have to keep running.
• Hybrid and electric cars usually cost more to buy than petrol cars, and charging infrastructure is less developed in rural areas.
• Infrastructure means the basic systems and services a country needs to function, such as electricity, water and transport networks.