European buildings account for large amounts of energy consumption and CO2 emissions and current EU policies target in decreasing their energy consumption and subsequent CO2 emissions. Realization of a small, grid-connected, residential building with zero CO2 emissions due to energy use in Crete, Greece shows that this can be easily achieved. Required heat and electricity in the building were generated with the use of locally available renewable energies including solar energy and solid biomass. Annual energy consumption and on-site energy generation were balanced over a year as well as the annual electricity exchange between the building and the grid. Technologies used for heat and power generation included solar-thermal, solar-PV and solid-biomass burning which are reliable, mature and cost-effective. Annual energy consumption in the 65 m2 building was 180 KWh/m2 and its annual CO2 emissions were 84.67 kgCO2/m2. The total capital cost of the required renewable energy systems was estimated at approximately 10.77% of its total construction cost, and the required capital investments in renewable energy systems, in order to achieve the goal of a residential building with zero CO2 emissions due to energy use, were 1.65 € per kgCO2, saved annually. The results of this study prove that the creation of zero CO2 emissions buildings is technically feasible, economically attractive and environmentally friendly. Therefore they could be used to create future policies promoting the creation of this type of building additionally to the existing policies promoting near-zero energy buildings.
The Sustainability of Decentralised Renewable Energy Projects in Developing Countries: Learning Lessons from Zambia