Harnessing wind, solar, and water energy

Use of wind energy

Wind is a renewable source of energy. People have long used the energy of wind – recall sailing ships and windmills. In the territory of Russia, the portion of wind that could be used with the current state of technology amounts to no less than 10 billion kW.

However, it is very difficult to make use of wind energy, since its speed constantly fluctuates within wide limits. Modern wind engines are designed so that they can operate at wind speeds from 2 m/s up to storm force. The blades of the wind wheel turn automatically when the direction and speed of the wind change. Various methods of storing wind energy are also used, although all of them are complex to operate and require large expenditures. It is most expedient to use wind installations where other sources of energy cannot be used.

Data on the wind regime are collected by the A.I. Voeikov Main Geophysical Observatory. These data are used in the design of industrial facilities, various aircraft, in city planning, and in the construction of tall structures.

Using formulas that take into account the wind rose, one can calculate the configuration and extent of the sanitary protection zone of industrial enterprises, within which housing construction should not be carried out.

The relief of the terrain has a great influence on the direction of air flows, especially in the case of weak winds, and on the associated transport of pollutants. It also affects the formation of surface inversions, which limit the height to which smoke rises from the chimneys of industrial enterprises.

Use of the Sun's energy: from nature to technology

The Sun is an inexhaustible source of energy that daily supplies the Earth with a colossal amount of heat and light. The energy of solar radiation underlies all climatic processes, biological cycles, and modern sustainable-development technologies.

Natural processes based on solar energy

Solar energy is the foundation of life on Earth:

• Photosynthesis: plants convert sunlight into chemical energy, creating organic substances and releasing oxygen.

• The water cycle: evaporation, condensation, and precipitation — all of this happens thanks to the heating of the surface by the Sun.

• Atmospheric circulation: temperature gradients caused by solar heating drive wind flows and form climatic zones.

Technological use of solar energy

Humanity has learned to use solar energy in various fields:

Energy conversion

Solar energy can be converted into:

• Electrical energy — by means of photocells.

• Thermal energy — through solar systems and solar cookers.

• Mechanical energy — for example, in steam turbines heated by sunlight.

Advantages and challenges

Advantages:

• Renewability and environmental friendliness.

• Availability in most regions of the world.

• Reduced dependence on fossil fuels.

Disadvantages:

• Dependence on weather conditions and time of day.

• The need for energy storage devices.

• High cost of installation in some regions.

Use of water energy

Water energy is one of the oldest and most reliable sources of renewable energy. Its use is based on converting the kinetic and potential energy of moving water into mechanical or electrical energy. This is an environmentally clean way of obtaining energy that plays an important role in sustainable development.

Historical use

Since ancient times, water has driven mechanisms:

• Water mills: used for grinding grain and processing wood and metals.

• Archimedes' screw: used for raising water in irrigation systems.

• Hydraulic presses and hammers: in metallurgy and construction.

These technologies formed the basis of industrial development before the advent of steam engines.

Modern forms of use

1. Hydroelectric power plants (HPPs)

• Convert the energy of falling or flowing water into electricity.

• Examples: the «Three Gorges» dam in China — the largest hydroelectric power plant in the world.

• Provide a stable supply of energy, especially in mountainous and river regions.

2. Tidal power plants

• Use the movement of seawater during high and low tides.

• Effective in coastal zones with pronounced fluctuations in water level.

3. Ocean wave energy

• Waves possess high specific power — up to 80 kW/m at a wave height of 2 m.

• A promising direction for countries with a long coastline.

4. Pumped-storage power plants

• Used for storing energy: water is pumped into an upper reservoir and released at times of peak demand.

• Allow the energy system to be balanced.

Use in agriculture and everyday life

• Irrigation: pumps powered by water energy provide watering of fields, especially in arid regions of Ukraine.

• Water treatment and distribution: hydropower is used in city water-supply systems.

• Autonomous systems: in remote areas — an alternative to diesel generators.

Advantages and challenges