For the practical implementation, the proposed CRAVEzero methodology, which is an addition to the fundamentals of nZEB designs (nZEBs as a purely technical concept) aims at reaching nZEB targets in eight major steps:
① Define energy and cost-related project goals
It is important to clearly define energy consumption and life cycle cost-related goals for the project in the first step. This step lays the foundation for defining key actions needed to achieve those goals, avoiding pitfalls and bottlenecks.
② Define actions to reach the goals and track them throughout the life cycle
Considering the complexity to reach nZEB-target with cost-optimal solutions for all the different stakeholders, multiple actions are required. However, these are usually missing in standard planning processes. Therefore, it is important to promote a shared, interdisciplinary understanding of the complexity of nZEB planning processes for all involved stakeholders. A well-organized and transparent process is a key issue of achieving the goal of cost-optimal and sustainable nZEBs throughout the entire life cycle. The CRAVEzero consortium, which provided its experience in the area of holistic project management with a focus on integral building planning, defined how key performance parameters, to achieve successful nZEBs, should be prioritized and can be tracked along the whole life cycle process. Additional advantages of this approach are:
- Risk reduction.
- Speed-up of construction and delivery.
- Control over costs and energy performance.
- Foster integrative design and make optimal use of team members’ expertise.
- Establishment of measurable success criteria.
③ Create win-win situations for all stakeholders
A win-win situation for the involved stakeholders needs to be created to push and support the nZEB market uptake. To do that, a win-win situation has to be translated into a business model.
Business models are usually based on cooperative strategies, where different stakeholders bundle their expertise to create positive outcomes for all processes, creating synergies and ‘win-win’ situations. Already existing and new examples for ‘Win-win-win’[AK1] nZEB business models have been analyzed during CRAVEzero project, showing advantages to different types of stakeholders, for example, planners, developers, construction companies and users, while positively contributing to the environment and society.
④ Select optimal nZEB technical solution sets
To realize cost-efficient nZEBs for all stakeholders throughout the life cycle, knowledge about the most important technology sets as well as possible cost developments of these technologies is essential.
The development of comprehensive solution-sets based on key industrialized components and renewable energy systems and its cost-effective integration in the design and construction process are major challenges. The CRAVEzero approach has identified technical and life cycle cost reduction potentials for each nZEB technology set to define robust solution sets based on industrialized multifunctional building components, easy and flexible to produce, install, and maintain.
⑤ Do life cycle cost analysis and variants
According to the ISO 15686-5:2008, the life cycle costing of a building is the net present value, which is the sum of the discounted costs and revenue streams during the phases of the selected period of the life cycle[AK2] . The life cycle phases generally included in the assessment are the cost for the initial investment (design and construction), the cost for operation and maintenance and the end-of-life residual value.
The implementation of LCC in the design phase allows moving the focus away from the initial investment perspective, including operation, maintenance and end-of-life stages as well. The advantages are that this methodology gives transparency to the operational phase of a building, awareness of total costs and the possibility to adjust these total costs already in the design phase. This approach leads to better determine the optimal solution-set from a cost-effectiveness point of view over a selected life cycle and allows:
- Balancing the cost of ownership and occupation, analyzing initial investment and running cost,
- Assessing risk and costs connected to maintenance and replacement due to failure,
- Supporting decisions, which consider sustainability.
Furthermore, LCC calculation can be adopted to compare building variants, alternative technology sets or mutually replaceable design alternatives as well. This approach allows selecting the most cost-effective solution, undertaking financial options evaluation. In this way LCC analysis becomes a tool that supports the decision making process.
⑥ Quantify co-benefits for nZEBs
It is essential to quantify the added value associated with green buildings and their impact on life cycle costs. Co-benefits such as increased productivity, improved health, publicity value, higher renting opportunities, reduced employee turnover and reduced absenteeism need to be quantified. The objective is to present new business advantages and opportunities to potential investors, going beyond technical performance analysis.
⑦ Learn from frontrunners and avoid pitfalls and bottlenecks
Cost and time are often overrun when constructing nearly-zero and plus energy buildings, due to unclear requirements, unclear processes and the lack of knowledge about these technologies. CRAVEzero project showcases frontrunner nZEB projects, which have been realized in a cost-efficient way, so that pitfalls and bottlenecks can be avoided in future projects.
⑧ Bring all together in the business case for nZEBs
The goal was to develop an effective methodology to achieve the best conditions towards cost optimal nZEBs, exploring the concept of integrating nZEB technologies and business models in the whole planning, construction and operation process. The evaluation and generation of enhanced and innovative business models are also part of the study of nZEBs. To generate new business models, it is necessary to identify what types of different business models already exist in the markets and what makes them successful or inconsistent.