3. Electricity systems

‘Electricity systems’ explains that the two essential functions of an electricity system are to take power from the generators and distribute it to consumers, and to balance the supply and demand of electrical energy. A secondary objective is to control the voltage but this is easier and cheaper to accomplish. The conventional structure of a modern electricity supply system and what should be considered in its design and operation is discussed before considering contemporary developments in electricity generation, transmission, and distribution. All aspects of the electricity system are entering a period of great change, especially in the distribution networks with rapidly increasing distributed generation.

4. Nuclear power

Of all the sources of energy used for electricity generation, nuclear power is the most contentious with strong opinions both favouring and opposing its use. Some well-known environmentalists consider that the use of nuclear power is essential to limit climate change, while expressing reservations over its environmental impacts. ‘Nuclear power’ explains that there are two mechanisms by which nuclear energy could be used to create heat and so generate power; nuclear fission and fusion. Nuclear power reactors create heat, which is used to make steam that is then passed through a turbine to generate electricity. The nuclear fuel cycle is described along with the different generations of nuclear reactors.

6. Future energy systems

Energy for a modern society must be affordable, reliable, and sustainable. ‘Future energy systems’ considers future electricity generation and electricity networks, including the Smart Grid. Electricity systems are expensive and the choice of technologies to be used is heavily influenced by their costs. Low carbon generation, such as nuclear and renewables, is particularly capital intensive. Local energy systems and microgrids are also considered alongside future gas systems. It is now being recognized that for the development of low carbon energy systems a more integrated and regional approach to energy supply is likely to be preferable. There are no short-term easy solutions to energy supply and all choices involve compromise.

5. Renewable energy systems

‘Renewable energy systems’ describes the different ways of harnessing renewable energy and methods of converting it into electricity, gas, or liquid fuel, and their advantages and disadvantages. Renewable energy systems use a broad range of technologies to capture and convert energy from natural energy sources that are not diminished as they are utilized. Most renewable energy comes from the sun. Natural processes convert heat from the sun into movements of wind and water in the atmosphere that are then used to generate electricity. Solar radiation provides the energy to grow biomass and sunlight is used to generate electricity directly through the photovoltaic effect. Other significant sources of renewable energy are the tides, and geothermal heat.

2. Fossil fuels

For the last 300 years the world has relied on fossil fuels—coal, oil, and natural gas—for its energy. The widespread availability, high-energy density, ease of transport and storage, and the generally low cost of fossil fuels has facilitated the development of modern society with all its benefits. ‘Fossil fuels’ explains, however, that the extraction and combustion of fossil fuels has severe impacts on the environment. It is accepted by most policy makers that continuing to burn carbon based fossil fuels cannot be sustained and we need to move quickly towards energy systems that emit greatly reduced amounts of CO2, but fossil fuels will continue to play an important role in energy supply for some years.

1. Energy systems

‘Energy systems’ explains the difference between energy and power and between energy and electrical energy. It then outlines the sources of primary energy, describing the environmental consequences of burning fossil fuels, and attempts at limiting energy use. It also considers the difficulties of storing electricity in large quantities and cost-effectively. It is impossible to conceive of a modern society without reliable and effective systems to provide energy when and where it is needed. Modern energy systems continue to evolve in response to energy demand and to changing sources of supply. Increasingly environmental considerations and costs determine which energy sources are used and how the energy transmission and distribution networks are constructed and operated.

Introduction

The Introduction outlines the structure of this VSI, which starts with a review of basic ideas and well-established energy systems before moving on to consider how a future energy system might be configured. Energy systems provide the solid, liquid, and gaseous fuels as well as electricity that we use in buildings, industry, transport, and agriculture. They are essential for modern life, but energy systems are changing at a pace not seen since electricity began to be distributed widely more than 100 years ago. The radical changes in both the supply and use of energy are being driven by the needs of modern society, environmental concerns, and rapid developments in technology.