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Renewable energy

Renewable energy sources such as solar, wind and geothermal do not cause air pollution and have low or no CO2 emissions. Another advantage is that the energy never runs out. This is in contrast to coal, oil and gas. The burning of these fossil fuels contributes to climate change. 


There are quite a few options of renewable energy sources these days that are succesfully in use. These are:


    • solar power


    • wind power (very popular in Scotland)


    • bio mass


    • water power (again very popular in Scotland)


    • Geothermal heat or ground source heat (up and coming in Scotland)


Because of the ideal fit with underfloor heating, we will limit ourselves here in this article to Geothermal energy or Ground source heat.


Ground source heat pumps


Heat from the ground and the water in the soil is a renewable form of energy. Depending on the depth is called the Earth’s heat or ground heat. Geothermal energy is in hard to reach in Scotland and therefore very expensive. Ground heat is achievable and ends up as heating for the in mainly new homes.


 (image credits: Studiovhf)

Geothermal heat and ground source heat are eco-friendly alternatives to the burning of gas and coal. Because the use of Earth and soil heat will hardly pollute, or have any CO2 emissions and will therfore not influence climate change. Another environmental benefit is that geothermal heat will never run out, unlike fossil fuels.


To sum it up:


    1. Heat can be drawn from get from the soil from a depth of 100 meters, and is used for the heating of houses, for example, but also commercial buildings and greenhouses.


    1. The water in the ground on 20 to 300 meters depth is suitable for heat-exchange: we can pump it up, then heat it stop (in summer) or take it out (in the winter) and then back again. This is called ground source heat.


    1. On very large depth (from 500 metres) geothermal energy can be used. Iceland is using it for heating.


    1. Geothermal energy originates in the core of the Earth. Ground source heat comes from the Sun.


Sources of Earth and ground heat


Sunlight warms the soil and the groundwater (especially in summer). By circulation of ground water and by the distribution of heat by the soil, the Sun can heat up to several hundred meters deep in the Earth’s crust. The heat in the soil and water in the soil are both called ground source heat. 


Nature core allows for geothermal


Geothermal energy comes from another source, namely, the hot core of the Earth. The temperature in the core is not exactly known, estimates range from 2.000 to 12,000 degrees Celsius. This form of heat is called geothermal, or geothermal heat.


The core heat spreads through the different layers to the Earth’s crust. Seen from the outside in, it is becoming warmer. Every kilometer we dig deeper, the temperature rises with 30 degree Celsius. Starting from 500 metres depth there is enough heat difference to be able to transport the heat to the surface.


How to extract ground source heat


The substracting of ground source heat to 100 meters deep in the Earth is done with so-called ground source heatpumps. Such a soil heat exchanger consists of a closed piping system that runs up to 100 meters deep in the soil. Pumped through the pipes is a liquid (usually water with antifreeze). The liquid flows through the warmer ground, heats up and flows through the tubes, back to the surface. On the surface the large heat pump systems take over the heat of the liquid in the heat exchangers, and transport it to the underfloor heating systems or other heating systems for domestic homes and industry.


Individual ground source heat pumps


In addition to large-scale heat pump systems, there are also individual heat pumps for the heating of interiors. They also use ground heat, but go much less deep into the ground. 


Storage of heat and cold in the bottom


In theory there is over three times more energy available in the Scottish soil than Scotland needs on an annual bases. Nevertheless, Scotland still makes little use of geothermal energy.    The UK Government has set a target of twenty percent of all energy consumption in the uk should come from sustainable sources by 2020 and has set up The Renewable Heat Incentive (RHI) to help boost this development . The scheme provides financial incentives to households and non domestic consumers.