Free Resources | Energy | Currents Newsletter | June 2001

Alameda County Solar PV: An Energy Efficiency Model

By Peter Asmus

Alameda County has always been a leader when it comes to reducing energy consumption at its own facilities. Today, in an era of wholesale price volatility, rotating blackouts, and growing concerns over global climate change, the county’s efforts to reduce reliance upon California’s stressed grid include the installation of the nation’s largest rooftop solar photovoltaics (PV) system.

By integrating rooftop solar PV panels with energy efficiency upgrades and state-of-the-art energy management software, Alameda County is able to reduce peak power consumption by 20% without any expenditure from its general fund. “Over the past several years, Alameda County has reduced electricity use by more than 30%,” said County Supervisor Scott Haggerty. “We are confident that solar energy is a very smart addition to our overall energy strategy.”

Matt Muniz has been Alameda County’s energy guru since 1993. His first job was to help change out the lighting ballasts at the Santa Rita Jail, located on the sunny eastern fringes of the county’s boundaries near the City of Dublin. All told, Muniz managed to spend $3 million from Pacific Gas & Electric’s (PG&E) “power savers” demand-side management program to retrofit inefficient lighting systems in 70% of the buildings owned by the county. This was no small feat, considering that the county owned a courthouse, administration buildings, jails, hospitals, social service structures and other public buildings that when combined represented 15 MW of peak electricity consumption.

Muniz was able to reduce electricity costs by a third at Santa Rita Jail. All told, lighting retrofit projects and HVAC upgrades now save Alameda County approximately $4 million annually due to these past investments.

A Marriage Between Solar and Efficiency
Berkeley-based PowerLight Corporation recently created a joint venture with Viron Energy Services, a Kansas City, Missouri-based firm that was recently purchased by CMS Energy, a large, sophisticated utility based in Michigan doing business in 21 different countries. PowerLight and CMS Viron Energy Services decided to join forces to showcase the synergy between solar photovoltaics and state-of-the-art energy efficiency devices and controls. Alameda County’s Santa Rita Jail would be their joint project and would serve as a model to be emulated by other local governments.

By linking a 500 kilowatts PV system with a patented R-11 rigid polystyrene foam roofing insulation, PowerLight’s PowerGuard tiles will generate 675,000 kilowatt hours of clean summer peak electricity while simultaneously reducing heating and cooling requirements. PowerGuard tiles also do not require any perforations of the roof. They protect the roof membrane from weather and ultraviolet radiation, which delivers additional economic benefits.

Alameda County now hopes to more than double its solar PV capacity by covering all 18 Santa Rita Jail housing units with PowerGuard. It is also investigating installing solar PV on three buildings it owns in Oakland. All told, Alameda County’s solar PV commitment could expand to 1.2 MW.

Efficiency and Smarter Controls

Alameda County’s Solar Lessons Much of the innovation of the Santa Rita Jail project stems from integrating solar PV with energy efficiency and smart energy management systems. By re-reroofing, buying and installing PowerGuard tiles, and incorporating energy efficiency upgrades all at the same time, administrative costs were lower than if the projects had been done separately. Perhaps the most impressive accomplishment has been the high level of public goods funding that Alameda County was able to capture to support this project financially. Since it provides substantial public benefits in the form of reduced peak electricity consumption in a region hampered by severe transmission constraints, these substantial public goods funds appear to be justified. Though the County’s total project cost was approximately $4 million on paper, the following incentives were awarded to this innovative project: $1 million from the California Energy Commission Emerging Renewable Buy-Down Rebates Program. Alameda County was able to secure this funding at the rate of $2.50 per watt. However, the Energy Commission recently raised this rebate amount to $4.50 per watt. Since this increase is retroactive to February 2001, Alameda County will receive additional funding under this program. $1 million fixed 6% interest loan from the California Energy Commission Energy Efficiency Financing Program (which will be paid off by avoided electricity cost savings over the next 11 years); $300,000 from the California Energy Commission’s AB 970 funds. This legislation authorized the spending of $50 million for energy projects that reduce the state’s demand for electricity this summer. CMS Viron Energy Services secured $250,000 from PG&E under its “crosscutting demand” program. The balance of funds came from preexisting county budget authorizations for roofing and energy projects.

CMS Viron Energy Services will deliver 975,000 kWh in electricity savings primarily from replacing an old inefficient chiller with a new 850 ton high efficiency, variable speed, chiller that does not rely upon the CFCs that contribute to the alarming ozone hole in the southern Hemisphere. The existing chilled water-pumping system pushed water through both chillers regardless of cooling needs. The new variable speed drive will respond directly to the precise real-time cooling requirements needed to deliver chilled water instead of always operating at 100% capacity.

A new computerized energy management system, which has been dubbed UtilityVision, will automatically reduce power consumption during peaks in response to short-term fluctuations in solar fuel caused by weather conditions such as cloud cover. For example, if clouds block the sun for five minutes on a summer afternoon, UtilityVision will automatically reduce power consumption proportionately so that no additional purchases of expensive peak priced electricity are necessary. Once the cloud passes, and solar electricity generation is resumed at maximum levels, the energy management software will automatically make corresponding adjustments to power consumption.

These kinds of sophisticated smart energy controls benefit all state consumers by reducing purchases of grid power during times of the tightest supply and highest demand. This is especially critical in the so-called Tri-Valley Transmission Line area, a region that includes the City of Dublin.

“The solutions offered through our alliance with PowerLight reflect the future of the energy industry,” said CMS Viron President John Mahoney. “As energy becomes more expensive, other public agencies will follow Alameda County’s lead and perform energy efficiency upgrades to help manage costs and revitalize aging facilities.”

Benefits to Alameda County and California
The alliance between Power-Light and Viron will save Alameda County almost $200,000 annually under previously frozen retail electricity rates. Because prices for purchased grid power for customers the size of Alameda County are likely to rise by as much as 50% – from the current 6.5 cents per kWh to 9.5 cents per kWh – these savings figures could easily double to $400,000 or more.

The environmental benefit linked to the 500 kilowatt solar PV system and energy efficiency improvements is a reduction of 200,000 lbs. of carbon dioxide, a global climate change gas, and 850 lbs. of the nitrogen oxides that contribute to urban smog, a primary cause of asthma and other respiratory diseases.

The project also offers accountability and transparency benefits. The project’s performance data will be posted on the Internet for other local governments and commercial customers to review and analyze the performance of both solar PV system and energy efficiency measures.

Several local governments, including the cities of San Jose, Santa Rosa, Livermore and Santa Clara County, have already approached Alameda County for more information about both how solar PV and energy efficiency work together and how the county was able to pay for these innovations without tapping into its general fund.

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