Net Zero Technologies for "pollution-free and cost-free energy" sounds far fetched, but it is actually a set of technologies already being used around the world to produce Net Zero Energy buildings. It is a combination of 5 key technologies that together can provide all of the energy needed by any building: PV (solar), GHP (geothermal heating and cooling, thermal batteries), EE (energy efficiency), sometimes Wind, and sometimes Electric Batteries. Each of these technologies will reduce a building's energy cost, and combining them can bring any building's GHG emmission to Zero.
Many find this new world of Renewable Energy and Energy Efficiency (RE/EE) very confusing, and often ask "should I do technology A or should I do technology B?". This is a completely erroneous question that comes mainly because to date the RE/EE world has been dominated by "technologies". We started Net Zero Foundation to overcome this RE/EE limitation by showing that Net Zero is the goal and the only goal, not a technology! The various RE/EEtechnologies involved are just tools to be applied as best they fit each site.
Thus, the only legitimate question now is "where do I start?" and "how fast should I implement these technologies?"
The key Net Zero technologies that a business or home owner can implement are PV, GHP, EE, and Batteries. We will go through each of these technologies in detail. The other Net Zero technologies, Hydro, Wind, GEO, and Nuclear are generally only implemented by utilities and large corporations.
PV - Photovoltaics
PV panels turn sunlight directly into electricity. The basic PV technology is a silica-based flat wafer similar to computer chips and LED technology, and manufactured in a similar factory. Early PV cells were "monocrystalline" and have been found to have a extremely long life, but they are also expensive to make and generally only used in remote locations where reliability is essential. The PV panels going on roofs and solar farms are "polycrystalline" cells and are far less expensive. PV installation cost in large installations is now about $2.50/Watt.
GHP - Geothermal Heat Pumps and Ground Energy Storate
GHP is a thermal energy technology that is the most efficient way to mechanically heat and cool any building. GHP is also a thermal energy storage technology, where the excess heat from cooling a building in the summer is stored in the earth for use heating the building the next winter. GHP is termed a Renewable Thermal technology because it uses a summertime recurring thermal energy source (waste heat from cooling) to later provide heating in the winter. This storage of thermal energy in the ground from one season to another is done with a Ground Heat Exchanger (GHEX) which involves special high-grade pipes buried in the earth. GHP can reduce the amount of power used for heating and cooling by a factor of 4x to 7x, and requires no fossil fuels.
EE -- Energy Efficiency
Energy Efficiency is the most basic energy conservation technology available. EE includes insulation, air leakage sealing, double-pane glass, low-e glass, etc. The slingle largest energy loss in a structure is typically air leakage. Newer EE technologies include spray foam insulation which provides both insulation from heat and cold, and also provides air leakage sealing.
Batteries -- Electric Energy Storage Batteries
The latest addition to the RE/EE mix is Electric Batteries. Lead-acid batteries in off-grid RE systems for some time, but they are dangerous and have a limited life. New battery technologies have made are now making these batteries useful in other ways. An Electric Battery quite simply lets one use electricity at a time other than when it was generated. Without a battery, you have to use 100% of any generated electricity at the very moment it is produced. The most common RE/EE way to produce electricity is PV, but of course PV only generates electricity when the sun is shining. We need electricity 24 hours a day -- batteries make that possible.
Hydro -- Hydroelectric Dams
Hydroelectric power is one of the oldest RE/EE technologies. Electricity is generated by using the power of falling water to turn a large generator. The sun provides the renewable energy by evaporating the water for it to fall again as rain upstream from the dam. Hydro power is very efficient once a dam is built, but building new dams is very controversial because they cause large areas to be permanently flooded. Hydro power is also an energy storage technology because the energy is present once the water is behind the dam, and generation can be ramped up and down to match demand to some degree. However, the amount of energy that can be stored is limited by the size of the dam and lake volume behind the dam.