CASE

Energy self-sufficient Otaniemi - study and results

Means of improving the energy efficiency and boosting the use of renewable energy sources are presented in a study conducted by Gaia Consulting Ltd. The study defines the techno-economic boundaries and guidelines in building an integrated local energy system.

The study revealed clearly that it is challenging to meet the energy self-sufficiency target both from the technological and economical point of view. On the basis of the survey, the technology choices can be limited to the most suitable and economically viable ones in the Otaniemi energy system. However, before making investment decisions, more detailed modelling of the sizing and functioning of alternative energy production transfer and storage systems is needed to estimate and compare the costs and benefits.

At the moment local energy production in Otaniemi is very minimal. In total solar, wind and geothermal energy cover only less than 1 % of all the energy consumption of Aalto University Properties Ltd. The solar energy potential in the area was estimated in the study. According to the estimations there are 60 000 square meters of usable roof-top area for solar energy. In addition solar energy could be built on the ground surface and on the walls of buildings. Geothermal heat could cover at least part of the heat demand in Otaniemi in relatively short term. Other energy production technologies that are less significant in Otaniemi according to the study are small-scale combined heat and power production, small-scale wind power and different types of heat-pumps.

According to the study it is more profitable to use most of the locally produced energy than feeding energy to the grid. Micro-grids that serve several buildings locally could be one possibility to raise the proportion of own consumption and therefore the cost-effectiveness of the system. Both electricity and heat can be stored in times of over-production. The problem in storing electric energy is that the large batteries are still very expensive and have a poor technical lifetime. In the future the possible electric car infrastructure in the area could possibly be utilized for storing electricity.

Two alternative scenarios for the development of energy consumption in the campus were drafted in the study. In the base scenario the total energy consumption in the campus will increase by 11 % between years 2014 and 2030. In the energy efficient scenario the total energy consumption will decrease by 13 % respectively. The energy efficiency renovations will have the biggest impact on the development of the energy consumption and these renovations are much more ambitious in the energy efficient scenario. It is understandable, that it is easier to reach local energy self-sufficiency in the energy-efficient scenario.