ORKNEY RENEWABLE ENERGY FORUM

Biomass

Biomass, also known as biofuels or bioenergy, is obtained from organic matter, either directly from plants or indirectly from industrial, commercial, domestic or agricultural products. The use of biomass is generally classed as a ‘carbon-neutral’ process because the carbon dioxide released during the generation of energy is balanced by that absorbed by plants during their growth.

However, it is important to account for any other energy inputs that may affect this carbon-neutral balance on a case-by-case basis, for example any use of fertiliser, or energy consumed in vehicles when harvesting or transporting the biomass to its point of use.

Hydroelectric

Hydroelectric power is the energy derived from flowing water in rivers, or from man-made installations where water flows from a high-level reservoir down through a tunnel and away from the dam. Water power was used for centuries to power machinery, for example for grinding corn or in mills and factories, but was largely replaced by steam power in the Industrial Revolution. Water power is now mainly used to generate electrical energy

Geothermal

Geothermal energy involves the exploitation of different grades of thermal energy stored within the earth. In certain geological areas, heat from deep within the earth’s interior can rise up to the surface. Whenever water enters fissures in this hot rock, it can become heated and can emerge on the surface as hot springs, or even as steam, creating features such as steam vents, geysers and hot mud springs. Alternatively, heated water can be trapped below the earth’s surface as a geothermal reservoir. This heat can reach temperatures of 400°C. Drilling to depths of over two miles can access it.

Ground-source heat is a different form of geothermal energy. It is extracted from the low-temperature heat (10–20°C) that is found at relatively shallow depths within the earth’s crust. This source of heat remains at a relatively constant temperature all year and can be taken from the ground itself or from groundwater. Heat pumps can increase the temperature to provide a more useful output temperature of around 40–50°C, ideal for low-temperature heating systems like under floor systems and radiant panels.

Solar

Solar energy involves capturing and harnessing the sun’s energy. There are three main ways of doing this:
Passive solar design ensures that a building’s form and fabric captures the sun’s energy and reduces the need for artificial light and heating.Active solar water heating converts solar radiation into heat, which can be used directly or stored.Solar photovoltaic (PV) panels or solar cells convert sunlight into electricity.

Orkney Marine Renewables