Net Zero can be looked at in a multi sectional or holistic approach of reducing Energy, Water, and Waste on a facility or home.
ENERGY - Produce as much energy as the facility or home uses.
The first thing to look at in a facility or a home is to analyze how much energy is being used and how to best reduce that energy consumption. Some of the things that should be completed first are to retrofit all appliances to an Energy Star appliance. Analyze your air and heating options and put in automatic controls or occupancy sensors on your lighting fixture. Replace all lighting fixtures to LED or Fluorescent lamps. Possibly upgrading to higher insulation and roofing materials. Once all of these steps have been completed, then you are ready for the final investment, a renewable energy production system. For example, adding solar photovoltaic modules to the home, a solar hot water heater, etc. If this was completed first you would only be able to generate enough energy for possibly just what you were able to reduce. The first and main goal in energy reduction to obtain net zero is REDUCTION.
WATER - Net Zero water installation limits the consumption of freshwater resources and returns water back to the same watershed so not to deplete the groundwater and surface water resources of that region in quantity and quality over the course of a year.
Strategies such as harvesting rainwater and recycling discharge water for reuse can reduce the need for municipal water, exported sewage or storm water. Desalination can be utilized to convert briny, brackish or salt water to fresh water so it is suitable for human consumption or irrigation.
To achieve a net zero water installation, efforts begin with conservation followed by efficiency in use and improved integrity of distribution systems. Water is re-purposed by utilizing grey water generated from sources such as showers, sinks, and laundries and by capturing precipitation and storm water runoff for on-site use. Wastewater can be treated and reclaimed for other uses or recharged into groundwater aquifers.
WASTE - To reduce, recover and reuse waste streams.
The approach to creating a net zero waste installation is similar to creating a net zero energy installation. The first approach to achieve net zero reduces, reuses, and recovers waste streams, converting them to resource values with zero landfill over the course of a year. The components of net zero solid waste start with reducing the amount of waste generated, re-purposing waste, maximizing recycling of waste stream to reclaim recyclable and compostable materials, recovery to generate energy as a by-product of waste reduction, with disposal being non-existent.
Every day, more recycling strategies are developed moving beyond metals, paper and cardboard to include mattresses, glass, plastics, batteries, computer printers and motor oil. The best strategy is to consider the waste stream when purchasing items, reduce the volume of packaging, reuse as much as possible, and recycle the rest. A true cradle-to-cradle strategy considers the end state at the time the purchase decision is made. A net zero waste strategy eliminates the need for landfills, protects human health, optimizes use of limited resources and keeps the environment clean.