Electrical Systems Introduction

In a typical commercial building, electricity accounts for 60% to 95% of the total energy consumption. The use of electricity has few ecological drawbacks on the building site. However, electricity generation for California buildings has huge environmental impacts. It is one of the largest consumers of fossil fuels, releasing carbon dioxide (the major greenhouse gas) and regional air pollutants – nitrogen oxides, sulfur oxides, ozone and particulates. As well, a significant proportion of California’s electricity is generated by nuclear reactors, which create radioactive waste with few indisputably safe options for long-term disposal.

Only 7% of California’s current electricity supply is renewable, mostly from wind turbines, micro-hydro and solar thermal generators, and photovoltaic collectors. As deregulation proceeds, consumer choice is expanding. By purchasing “green power”, users can encourage investment in new renewable electricity generation. However, these choices typically have a cost premium, wind turbines and PV collectors take time to build, and there is no guarantee that building occupants will sign “green power” contracts.

The most effective strategy to limit the environmental damage – and operating cost – of electricity use of buildings is to reduce their power demand and electrical consumption. A building’s electrical demand and consumption is greatly influenced by architectural and mechanical design decisions. The most cost-effective, enduring and foolproof steps to reduce electricity use in Santa Monica are outlined in the Site and Form, Envelope and Landscaping chapters:

• Control solar cooling loads.
• Use sunlight for passive solar heating
• Use natural cooling and ventilation.
• Incorporate daylighting.

Relying solely on efficient equipment and lighting technologies without these architectural strategies typically costs more to build and to operate over the lifetime of the building. Designing a building that needs smaller transformers, little or no mechanical cooling and less electric lighting power is the best way to reduce energy demand and consumption, and capital and operating costs.

Efficient Equipment and Life-Cycle Cost Assessment

Climate-responsive design can reduce the size and amount of electrical lighting, heating and cooling equipment. The capital savings can then be applied to purchasing more efficient electrical equipment, such as transformers and motors. Life-cycle cost assessment is especially valuable when selecting equipment with large capital costs and long operational lives. New computer tools, such as CITCEM or MotorMaster, make it easy for designers to optimize equipment choices with life-cycle cost assessment, for both initial and long-term savings. Both of these tools are available for free download via the Internet; the Further Information section at the end of this chapter gives their addresses.

For less costly or long-lived equipment such as motors under 10 horsepower, the advantages of premium quality and efficiency are clear. The payback period is very short, maintenance costs are lower, and life-cycle assessment is typically unnecessary.

Fixture and Lamp Selection

Federal and state regulations have encouraged the move away from less efficient lighting technologies. In response, manufacturers are producing increasingly efficient equipment, and the range of choice is now very large and expanding rapidly. Keeping current is difficult for non-specialists and retaining a lighting design specialist can often pay for itself in reduced design time and lighting system cost – in both daylit and non-daylit designs.

Whether a lighting specialist or an electrical engineer does the design, the quality of light should be the primary consideration, with energy consumption an important secondary consideration. Quality issues include light distribution, contrast and glare. Good designers will meet these needs while minimizing the number of fixtures required, electrical demand, energy consumption, and capital and operating costs.

Integrating Daylighting with Electric Lighting

However well designed and efficient lighting equipment may be, the highest quality and most efficient light source is daylight. It offers the most accurate color rendering, and is welcomed as the best light source by most people.

During daylight hours, good lighting design looks first to natural lighting, and then to electric lighting as a supplement. Indirect, efficient electric lighting design uses the same surfaces to distribute light as does daylighting, and aims to make their lighting quality indistinguishable.

The best lighting will be different for every task and in each design. Where tasks require higher illumination, or drama is desired for esthetic reasons, the most energy-efficient strategy is to supplement general area lighting with direct lighting only in the desired areas.

Even the best lighting design can fail unless controls are considered and located with the final space use and furniture placement in mind, and carefully commissioned.

Photovoltaic Electricity Generation

While the initial cost of photovoltaic (PV) electricity generation is currently high relative to purchased power, a small but growing number of building purchasers and tenants consider this a valuable feature – a visible commitment to renewable energy, and a marketing benefit.

According to a study by the Sacramento Municipal Utility District, a four-kilowatt net-metered system (requiring no batteries) installed on a customer site would save $50 per month, for less than $24,000 capital cost. Prices for customer-installed PV collectors and electrical systems are projected to drop by 9% per year.

Customer-owned PV systems are rapidly becoming more economic for several reasons:

• Growing mass production is being reflected in quickly falling costs.
• PV collectors are increasingly integrated with building claddings, roofs and canopies, replacing traditional finishes and their costs.
• New codes, regulations and rates allow small systems to connect to the utility grid, eliminating the cost of batteries.
• Federal and state tax benefits and financial incentives are increasing in value and availability.

Few building developers are currently aware of these benefits. Besides strictly monetary advantages, many companies are reaping marketing rewards for PVs' visible commitment toward green goals. Forward-thinking designers are raising PV installation issues with their clients, and considering them carefully.

While design of most commercial buildings in Santa Monica strives to reduce building cooling loads by rejecting solar radiation, photovoltaics require unshaded access to the solar resource to perform optimally. This can be resolved by using PV collectors as window shades, or by locating collectors on roofs or south-facing walls. If PV collectors are not installed initially, forethought in envelope and electrical design can greatly ease future PV installation, as costs drop.

Electric Vehicle Charging Stations

With the State of California requiring that zero-emission vehicles form a significant proportion of new automobiles sales by the year 2005, electric vehicles (EVs) could become a common sight on Santa Monica streets and parking lots. However, scarcity of charging stations is a potential barrier to widespread acceptance of electric vehicles. However, there is still no universal standard for EV charging stations, which presents a challenge for designers and builders. While standards are being established, developers can anticipate future charging station installation by providing conduit, electrical panels and other equipment to make their future installation easier and cheaper. Anticipating the future needs of occupants (and their vehicles) is part and parcel of the thinking that underlies green building design.