Sustainable energy is a general term of bio-energy, wind power, solar energy, geothermal energy and other technologies that differ from coal and other fossil fuels by being CO2 neutral. The use of sustainable energy sources contributes to the reduction of our emission of greenhouse gas and to making Denmark independent of fossil energy.
The government's ambition is to make Denmark free of fossil fuels by 2050. This means that by 2050 Denmark should be able to produce enough renewable energy to cover the total Danish energy consumption.
Bio-energy is energy stored in organic material or biomass. Biomass can be incinerated directly or be processed for various kinds of fuels e.g. wood pellets, fermentation gas or bioethanol. Some kinds of biomass are vegetable such as e.g. straw, wood and alga. Other kinds of biomass are animal such as livestock manure and animal fats.
Bio-energy represents more than 2/3 of Denmark's total consumption of sustainable energy and is a growth market, as several power plants change from fossil energy to wood pellets, wood chips or straw. The production of fermentation gas is growing fast and is expected to triple in the period 2012 to 2020.
Biomass can be stored, which is not yet possible with wind power and solar energy. Consequently, bio-energy will probably play an important role as to ensuring security of supply in a future energy system
Read more about bio-energy on the Danish Energy Agency's website
In 2016 wind power represented 37,6 % of the total electricity supply in Denmark. Furthermore, the mounting of new windmills ashore is one of the cheapest ways of expanding electricity production. In this way, wind power is the most common type of renewable energy in Denmark and it is the most competitive kind of sustainable energy compared to other kinds of energy. Windmills can be established ashore and offshore.
Read more about wind power on the Danish Energy Agency's website
In Denmark, solar energy is used in two ways:
1) Solar cells for production of electricity. In 2015 Danish solar cell plants produced an amount of electricity corresponding to 1.8 % of the total Danish electricity consumption.
2) Solar collectors are used for heating of buildings and for production of district heating by means of sunbeams heating the water. Solar collectors are often combined with a heat pump.
Read more about solar energy on the Danish Energy Agency's website
Geothermal energy is in the underground in the form of hot, salty water. The temperature in the underground layers rises proportionally with the depth, as heat flows from the inner of the earth towards the surface of the earth. The temperature at a depth of 1-3 kilometres is about 40–80 °C.
The heat in water can be used for energy to heat supply in the district heating system. In Denmark, we get geothermal energy from plants close to Thisted, on Amager close to Copenhagen and in Sønderborg. In Denmark, geothermal energy is used to a limited degree.
Read more about geothermal energy on GEUS's website
Read more about geothermal energy on the Danish Energy Agency's website