Lighting: The efficiency of fluorescent lighting used in many larger commercial and industrial buildings is expected to improve by about 10 percent by 2025. This improvement, when combined with more adaptive lighting arrangements, could increase savings by about another 15 to 20 percent.
Incandescent lighting, although used less in commercial and industrial buildings (compared with homes), is also predicted to increase in efficiency by about 10 percent.
One alternative lighting system for commercial buildings is called hybrid solar lighting. In this system, a roof mounted solar collector sends the visible portion of solar energy into light-conducting optical cables, where it is piped to interior building spaces.
Controllers supplement this light as necessary with fluorescent lights to provide the desired illumination levels at each location. Early experiments show that hybrid lighting is a viable option for lighting on the top two floors of most commercial buildings. It would therefore be applicable to roughly two-thirds of the commercial floor space in the United States.
In retrofit markets, hybrid lighting can be more readily incorporated than skylights into existing building designs, and unlike skylights, the flexible optical fibers can be rerouted to different locations during renovations. This technology is estimated to have a payback period of fewer than five years for some applications.
For the long term, research into solid state lighting shows great promise. Preliminary roadmaps estimated that cumulative savings by 2020 could amount to 16.6 quads of electrical energy and 258 million metric tons, or 0.2 percent, of the projected total U.S. carbon emissions over that time period.
Today's light emitting diodes (LEDs) produce light at an efficiency only slightly higher than standard incandescent lights and are already used for specialty applications such as traffic lights and exit signs.
Technology improvements are expected to bring brighter LEDs that provide light equivalent to existing fluorescent fixtures with 25 to 45 percent less electricity usage. With successful LED R&D, energy savings over all sectors could be as high as 3 to 4 quads, or 60 to 75 MMTC, in 2025.
Global use of this technology is projected to save 1,100 billion kWh/year, corresponding to reduced carbon emissions of roughly 200 MMTC.
Climate-Friendly Distributed. Energy Distributed energy resources are small power generation or storage systems located close to the point of use. Not all distributed energy is climate-friendly, a case in point being diesel-generator sets.
But other distributed generation technologies offer significant potential for reduced emissions of CO2 and local air pollutants, partly because of their higher efficiencies through cogeneration and partly through their use of on-site renewable resources and low-GHG fuels such as natural gas. Other advantages in clude fuel flexibility, reduced transmission and distribution line losses, enhanced power quality and reliability, and more end-user control. Many experts believe that these potential advantages will bring about a "paradigm shift" in the energy industry, away from central power generation to distributed generation.
Some distributed generation technologies, like photovoltaics and fuel cells, can generate electricity with no, or at least fewer, emissions than central station fossil-fired power plants. Additional emissions can also be avoided using fuel cells, microturbines and reciprocating engines, if the waste heat generated is usefully employed on site to improve overall system efficiency. Based on the remaining technical potential for cogeneration in the industrial sector alone, it is estimated that nearly 1 quad of primary energy could be saved in the year 2025.
Packaged cogeneration units that include cooling capabilities (and are therefore more attractive to commercial building operators) are projected to save 0.3 quads in 2025.
Today's distributed generation market in the United States is largely limited to backup generation. Customers include hospitals, industrial plants, Internet server hubs and other businesses that have high costs associated with power outages. Markets are likely to grow as wealth increases and more consumers are willing to pay to avoid the inconvenience of blackouts.
Smaller niche markets are growing where distributed energy resources are used as a stand-alone power source for remote sites, as a cost reducer associated with on-peak electricity charges and price spikes, and as a way to take advantage of cogeneration efficiencies.
Distributed generation could be particularly advantageous in newly settled areas by requiring less infrastructure investment, by reducing transmission line requirements, and by being more responsive to rapidly growing demand for power. Increased demand will likely continue and possibly accelerate well into the future as small-scale modular units improve in performance; as decreases in cost, interconnection, and other barriers are tackled; as the demand for electricity continues to grow; and as the worldwide digital economy expands.
Over the next half-century, it is possible that the demand for ultra-reliable power service will increase far more rapidly than the demand for electricity itself. This demand could be met by distributed energy resources.
For distributed generation to enhance system-level efficiency, improvements would be needed in the performance of power-producing equipment. A next generation of power electronics, energy storage, and heat exchangers would be needed to improve waste heat recovery and cycle efficiencies, and advanced sensors and controls would also be required. With successful RD&D, the United States (and much of the rest of the world) could realize a paradigm shift to ultra-high-efficiency, ultra-low-emission, fuel-flexible, and cost-competitive distributed generation technologies.
These technologies would be interconnected with the nation's energy infrastructure and operated in an optimized manner to maximize value to users and energy suppliers, while protecting the environment.
