The term Renewable Green energy community is an often misunderstood and/or misinterpreted term, which, for many of us, sounds like a buzzword of the future. While we are all familiar with renewable green energy and we all understand that this includes, solar, wind, biomass and hydro energy, we cannot associate and or understand how all these forms of energy can be integrated together and when combined with many other green energy saving ideas set the basis for a truly renewable Green energy community.
Before expanding in this area we must first understand what we mean by the term, ‘’Renewable Green Energy community’’. A Renewable Green Energy Community, RGEC, is a state of the art community which is by design and implementation a community that runs on renewable green energy of one or many forms, meeting the demand and satisfying the needs of its residents and returning any excess energy to the grid to be used by other communities. The term ‘’Community Renewable Energy, CRE’’ is something different and refers to a locally owned renewable energy production site. This can be a subset of the Renewable Green Energy Community or not related at all to it.
A Renewable Green Energy Community, RGEC, according to the NREL definition should have the following 4 characteristics:
- Near-Zero or Zero-Energy Buildings and Homes
- Integrated Advanced Transportation modes
- Community renewable green energy generation
- Incorporated community living practices
The challenge for building such a community is the ability to design it and operate it in a sustainable mode and be able to integrate all of its components so that they would operate in a virtuous circle. So adding to the above 4 characteristics we have the key element of the sustainable design approach that is the first and most crucial step in order to achieve the creation of RGEC.
The sustainable design phase is the phase where designers, planners, developers and builders get together and provide the necessary input so as to ensure that the community’s needs for energy will be accommodated from the use of renewable green energy sources, will eliminate or minimize to zero the need for non-renewable energy, be sustainable and environmentally friendly. Some of the principles that should guide the RGEC designers in order to ensure, to a great extend, sustainability are the following:
- Energy efficient construction of buildings and homes
- Passive solar design so as to ensure maximum solar gain for cold climates and minimum for hot climates
- Ecological Integrity that would include water conservation
- Reduction of vehicle use through the proper design and layout of the community
Buildings in the Renewable Green Energy Communities used Solar Photo Voltaic, PV, cells on rooftops for the production of electricity. The buildings in such communities are designed to be Zero Energy Buildings, ZEBs. A Zero Energy Building, ZEB, is by design a building with PV on the roof and designed and built with energy efficient material so as to reach zero or near-zero energy use. The same applies to houses so as to achieve the Zero Energy Houses, ZEHs. There are many communities around US and in the world in general that are designed to have ZEBs.
In order for a RGEC to able to operate to a great extend on renewable green energy, it has to build a local energy production system, connected to the community micro-grid, that is build near the community, runs on renewable green energy such as wind or hydro or Solar and supplements the needs for energy to households and buildings. Connected to the community micro-grid there is a need to build energy storage systems so as to store energy that will be used by the community in the cases that the production of renewable green energy is not possible. If an energy storage system cannot be build then the community micro-grid has to be connected to the local power grid. Community renewable green energy can be central or distributed and there are pros and cons for each type or approach.
It is well understood that RGECs are currently small and certain of their elements and components are at their experimental or infancy stage. However such communities are emerging in various parts of the world and with their interaction and the viral exchange of ideas they are becoming sustainable and their model economically beneficial for their residents.