Associate Professor, Aalborg University

100% Renewable Energy for Denmark

100% Renewable Energy for Denmark

on Apr 27, 2013

This summary presents the main results of applying the tools and methodologies developed in the CEESA project to the design and implementation of 100% renewable energy systems in Denmark before 2050.

It is found that the transition from the present energy system dominated by fossil fuels to a system dominated by renewable energy sources requires significant changes in existing policies on both supply and demand sides. This is a change from polluting energy systems dependent on depleting inputs to energy systems that depend on non-depleting inputs and which are relatively abundant, non-polluting and intermittent.

In order to succeed, such change requires the system based on renewables to be supported by strong and efficient energy conservation. In Denmark, wind power and biomass are expected to be the two dominant resources in the short and medium term perspectives. In order to ease the pressure on wind and biomass resources, energy conservation becomes essential and so does the inclusion of contributions from additional sources such as solar and geothermal energy.

The change requires infrastructure where intermittent renewable energy sources can be managed in such a way that energy is available at the right time and in the right amount for the consumers. A main challenge for the transition planning is to obtain an efficient co-ordination between investments in the electricity, transportation, and heat sectors.  The policy instruments include new systems of taxes, subsidies, tariffs, and other economic conditions in order to obtain an optimal effect.

One main problem is to assure an energy-efficient use of low-temperature sources from CHP, waste incineration, industrial surplus heat and geothermal energy. In this relation, a new generation of low-temperature district heating infrastructure becomes essential.

Another part of the main problems in a future energy system dominated by intermittent renewable sources (e.g. wind and solar energy) is the stability of the electric grid and the security of supply to electricity consumers. In this connection, biomass in different forms plays a central role as a storage element. However, biomass is also required in the transport sector and for high-temperature industrial process heat (transformed to a liquid fuel or to biogas) while the amount of Danish biomass, taking into account other uses of the land area, is rather limited. In this respect, it becomes important to use the existing natural gas grid including substantial gas storage capacity in order to distribute and store biogas and syngas in future renewable energy systems. The CEESA project presents a technical scenario towards 2050 that achieves the specified goal with emphasis on infrastructures of transport and electricity supply as well as district heating.

The CEESA scenario proposes that the best solution is to let electricity from wind power replace the demand for biomass where possible and to stabilise the grid by other means than biomass where relevant alternatives are available. These means include systematic use of heat pumps and heat storage, eventually combined with electric cars.  In addition, new and efficient communication systems between energy suppliers and consumers are required, often described as “intelligent grids” or “smart grids”. The proposed policy means are selected in accordance with these technological solutions.

The CEESA project has documented that it is possible to find technical solutions for a 100 % renewable energy system that meets the required conditions with a satisfactory societal economy. However a certain technological development becomes essential for the coming years. The project has also described a number of new policy instruments for implementing the renewable energy scenario.

A full description about the CEESA project can be obtained from the final reports on the project homepage: