Producing electricity by wind and PV is respectful to nature and the local environment. To estimate the total power consumption on Vejroe, Balslev has been working with a data collecting system covering all buildings and energy consuming installations on the island and results have provided the necessary basis for decisions.
At present, the energy consumption in wintertime is low, as during wintertime there are only few people living on Vejroe. In the summertime the power consumption increases intensively, because of the peak in summertime activity.
Today energy is produced by 180 kVA diesel generator sets and an oil burner. The diesel engines supply energy for the district heating and the electrical grid. Today the annual diesel cost is approximately 1 million DKK (134.000 Euros) for approx. 146.000 liters of diesel.
A SCADA system has been installed to examine the total energy consumption on the island. The recorded data shows a significant heat loss from the district heating.
The project is to scale down the need for the diesel generators to an absolute minimum and produce the power needed by using renewable energy technologies.
On Vejroe it is expected to install:
– Photovoltaic panels (40 kW)
– 2 wind turbines (2×25 kW)
– Batteries for energy storage (120 kWh)
The photovoltaic panels will be placed on the roof of an existing building such as the generator building which is south-facing. A 400 m2 of photovoltaic panels with 30 degree slope will be optimal on a sunny day, and able to produce enough energy during day time and to save some for consumption overnight.
The wind turbines have a nominal capacity of 2×25 kW and can be disconnected for maintenance and repairs. The wind turbines will be placed in open area and, where possible, be integrated into the landscape. In addition, the location of the wind turbines will not impair the visibility of the lighthouse.
Battery storage will be used to provide energy overnight or when the production from PV and wind is too low. The sizing of the battery storage capacity is based on 20 kWh consumption at night for 6 hours. The battery storage system will be used on a daily basis, with one deep discharge and charging as a minimum. Lithium-ion batteries is appropriate for this task. The capacity is finally chosen at 120/140 kWh.
Summer is the commercial activity period and the need for the heating system is no longer as large as in winter. In order to save energy losses in wintertime the hot water for district heating will be produced and transported at 40°C which is sufficient to provide a correct temperature in the houses. Electric water heaters will be added in buildings to produce hot tap water.
The total investment for photovoltaic panels, wind turbines, battery storage and auxiliary are calculated to about 2,0 mio. DKK. The repayment period for the project will be app. 3 years.
Over a year it’s approx. 100.000 liters of diesel saved, i.e. approx. DKK 500.000.
As 1 liter of diesel oil emits 2.9kg of CO2 in the atmosphere, 423.000 kg of CO2 is removed pr. Year. That is equivalent to the emission from 62 households during one year.