Designing PEBs requires a detailed economic analysis to ensure they remain affordable in the long term. A 30-year life cycle cost (LCC) analysis is recommended, using a discount rate (e.g., 1.0%) to account for the present value of future costs. This analysis considers all costs: capital, energy, maintenance, and potential revenues from selling surplus energy.
How does the lifecycle cost analysis work?
- LCC analysis is performed over a 30-year lifespan to account for component service life.
- Include capital costs, energy expenses, maintenance costs, and revenues from surplus energy sales.
- Revenue from renewable energy generally comes from electricity generation via solar PV.
- Revenue depends heavily on how surplus electricity is used: as grid remuneration is typically lower than purchase costs, it is more convenient to distribute surplus electricity to building residents first, offering it at a rate 10% lower than standard tariffs to make it attractive.
- Maximize self-consumption is crucial in make Plus Energy Buildings affordable in scenarios with fixed energy prices and no peak power tariffs.
Insights from existing Plus Energy Buildings
The Plus Energy Buildings demo cases constructed in the project Cultural-E required an additional investment of €200–€250 per m² compared to a reference nZEB (nearly zero-energy building, a building that requires a very low amount of energy) with similar features.
Several strategies can be put in place to keep affordable costs.
- Use on-site renewable energy efficiently to minimize dependency on imported energy.
- Carefully select technologies based on cost, context, and performance.
- While decentralized HVAC systems offer benefits, they can increase overall investment costs by up to 10% compared to centralized systems.
- Minimizing grid energy imports and maximizing on-site energy use is a must.
LCC analysis is an essential part of the design of Plus Energy Buildings, to ensure they will be affordable over the building’s lifecycle.
Detailed guidelines and tools for LCC analysis are available in the report Guidelines and calculation methods for Lifecycle Environmental Impact Assessment of Plus Energy Buildings which include business models to market the benefit of PEBs.
