Net Zero Energy Buildings Are Achievable Today
Net Zero Energy Buildings are possible with today's technology. If widely implemented, Net Zero energy buildings would reduce US energy use by 50%
Buildings consume 40% of all energy in the U.S., 72% of all electricity and 55% of all natural gas. In the U.S., we spend $350 billion on energy for buildings … and that number is growing. The International Energy Agency (IEA) estimates that current trends in energy demand for buildings will stimulate about half of energy supply investments through 2030. If building site energy consumption in China and India grows to current U.S. levels, China’s and India's consumption will be about four and seven times greater than they are recently.
Stemming this tide requires a two-pronged approach to building design and operation. First, buildings must be designed and operated to consume far less energy than they do recently. Second, buildings must generate some form of renewable energy to offset their more modest energy consumption. This concept is called Net Zero Energy Buildings (NZE).
A handful of states have set goals around NZE buildings, but continuing its clean energy leadership, California has among the most aggressive goals:
- 100% new construction ZNE by 2030
- 50% of existing building are ZNE by 2030
So how do we get there? On the generation side, onsite photovoltaics seems to be the most effective and economical generation solution. With costs continuing to decline and conversion efficiencies constantly improving, solar PV is quickly becoming the onsite renewable generation of choice. Of course, this will require advanced energy storage solutions to enable 24x7 building operations.
On the demand reduction side of the equation, advancing technology may provide the answers.
The two biggest energy hogs in buildings are lighting and HVAC. LED lights provide a simple way to take a huge bite out of building energy consumption. Because they consume as little as 10% of the energy of traditional incandescent bulbs, without using dangerous mercury, LED lighting is the wave of the future. With costs on the decline, LEDs make particularly good sense for large commercial buildings because they last between 10,000 and 50,000 hours, offsetting high initial costs with dramatically reduced operations and maintenance costs.
HVAC energy consumption can also benefit from improved technology. Advanced monitoring of air flow and temperature enables better regulation of ventilation systems, chillers, boilers, and lighting and can reduce fan energy consumption by 20%. Motion sensors for indoor and outdoor lighting can eliminate up to 30% of lighting expenses. Diagnostic software provide better insight to what is happening in the building and advanced analytical tools help operators compare performance to nearby buildings. Last year, the California legislature passed AB 1103, which requires disclosure at time of sale or lease of a commercial buildings energy use score for the previous 12 months. This benchmarking law is an important step to providing more insight into building energy use and creating a market for more efficient buildings.