World energy supply

In Chapter 2 we noted that there are only three sources, or categories, of primary energy fossil fuels, renewable energy, and nuclear power. The global consumption of energy, broken down into these categories, is shown in Figure 5.1a. It can be seen that almost 80 of all of our primary energy needs are supplied from fossil fuels. The distribution of energy supply by source is further broken down in Figure 5.1b, which shows the largest fossil fuel component of the overall global supply to be...

Energy

Energy can be defined as the capacity to do work,'' and many different units are used. Energy can be found in many different forms, including chemical energy, as contained in fossil fuels, and thermal energy which can be related to the work which can be done as a result of a temperature difference in a substance. Electrical energy is that form of energy in which a flow of electrons can be used to do work with an electric motor, or to provide heat from a resistor network. The basic energy unit...

Energy and the environment

There is little doubt that the large-scale utilization of fossil fuels is putting significant stress on the environment. The effects of combustion products on air quality and the climate are both local and global in nature. The local effects, primarily in the form of air pollution and smog formation in large urban areas, have been known for many decades, and in recent years government regulations to reduce the effects of air pollution have been significantly strengthened. These include both...

Renewable energy sources

Renewable energy sources are primarily those which are inexhaustible in nature, and which are ultimately derived from the radiant energy of the sun reaching the earth. These include the obvious examples of hydroelectric power, solar energy, and wind power, as well as some not quite so obvious examples, such as combustible renewable wastes and biomass fuels like ethanol made from grain crops. In addition, sources such as geothermal energy and ocean gradient energy, which are derived from the...

Solar thermal energy systems

One way of utilizing solar energy is to use it directly as a source of thermal energy, either to provide space heating for residential and commercial buildings, or to generate electricity using a conventional Rankine steam cycle. As we have seen, a great deal of energy is used to provide basic comfort in buildings, and in the populous mid-latitude countries this is primarily used for heating during the winter months. The use of both active and passive solar thermal energy systems for these...

Nonconventional fossil fuels

We have seen in the previous chapter that there will be considerable pressure on conventional fossil fuel reserves over the next few decades. Demand for oil in particular will experience substantial annual growth, and it will be difficult to maintain the recent historical reserves-to-production ratio of around 40. There is a need, therefore, to develop new or non-conventional sources of fossil fuels to supplement the traditional crude oil supplies. These will likely be needed until at least the...

The energy conversion chain

Tidal Power Simple Sankey Diagrams

Every time we use energy, whether it's to heat our home, or fuel our car, we are converting one form of energy into another form, or into useful work. In the case of home heating, we are taking the chemical energy available in natural gas, or fuel oil, and converting that into thermal energy, or heat, by burning it in a furnace. Or, when we drive our car, we are using the engine to convert the chemical energy in the gasoline into mechanical work to power the wheels. These are just two examples...