Davis Energy Group

Davis, CA, United States

Davis Energy Group

Davis, CA, United States

Time filter

Source Type

Heinemeier K.,University of California at Davis | Heinemeier K.,Western Cooling Efficiency Center | Hunt M.,Pacific Gas and Electric Company | Hoeschele M.,Davis Energy Group | And 2 more authors.
ASHRAE Transactions | Year: 2012

HVAC maintenance measures in residential and small commercial buildings have been demonstrated in the laboratory to have the potential to save a significant amount of energy. This significant potential for savings has prompted utilities across the nation to include HVAC maintenance measures in energy efficiency programs. This is currently seen as the cutting edge of utility HVAC programs. However, evaluation, measurement and verification (EM&V) studies of these programs have shown mixed results. This paper presents analysis of the sources of uncertainty in delivering and measuring these programs. The gaps that can account for the discrepancy between the potential and the measured savings are described. By identifying the range of issues, program planners can address as many as possible of the potential sources of uncertainly. Measurement issues are of particular focus. An analysis is done of the uncertainties in the measurements of common variables as measured in the laboratory, by EM&V teams, by participants in maintenance programs, and by typical contractors. These uncertainties were combined to identify the resulting uncertainty in the calculated subcooling, superheat, EER values and annual kWh. The remainder of this paper presents recommendations for improving maintenance measures, based upon the uncertainties identified. ©2012 ASHRAE.


Greenwald S.F.,Davis Energy Group | Gray J.P.,Davis Energy Group
Power | Year: 2011

Significant increases in intermittent renewable generation are expected to meet renewable portfolio standard (RPS) requirements and greenhouse gas emissions reduction measures. The North American Electric Reliability Corp estimates that ≈ 180,000 Mw of variable wind and solar generation may be added in North America by 2019. To help integrate renewable resources, the tools warranting further development includes enhanced forecasting, additional transmission to facilitate inter-balancing authority transactions, greater demand response, and increased energy storage. However, grid operators can be expected to lean heavily on the nation's gas-fired generation fleet to meet integration needs. Flexible gas-fired generation in excess of historic planning reserve margins will be required to reliably integrate increased renewable generation. However, capacity markets that have traditionally viewed resource procurement in terms of planning reserve margins and "resource adequacy" are not equipped to suitably value and compensate generators for renewable integration services.


Greenwald S.F.,Davis Energy Group | Gray J.P.,Davis Energy Group
Power | Year: 2012

In 2002, California enacted legislation authorizing municipalities to establish Community Choice Aggregation (CCA) programs. In September 2012, the San Francisco Board of Supervisors adopted CleanPowerSF to be the CCA program available for city residents. CleanPowerSF is described as a 100% renewable energy alternative. A discussion on CleanPowerSF covers the complexities and challenging tradeoffs driving energy realities demand that energy policy be developed on a regional basis; California's deregulation experiment; promised benefits; marketing for CleanPowerSF; legal infrastructure; and cost issues.


Prabhakaran V.,Davis Energy Group
Power | Year: 2012

San Francisco City Attorney Dennis Herrera filed a case against the US Pipeline and Hazardous Materials Safety Administration (PHMSA) that allegedly "abjectly failed to oversee the California Public Utilities Commission's (CPUC) pipeline safety program or to ensure that federal pipeline safety standards are enforced. The complaint links these failures by the PHMSA to the natural gas pipeline disasters recently experienced in the Bay Area.The complaint also criticizes what it asserts to be ineffectiveness by the CPUC in regulating PG&E and other operators of natural gas pipelines. The lawsuit seeks injunctive relief directing the PHMSA to comply with its duty to oversee certified state authorities and to ensure that federal pipeline safety standards are enforced as required by the Pipeline Safety Act. It further requests that the court enjoin the PHMSA from improperly delegating their authority to do so to gas pipeline operators like PG&E.


Greenwald S.F.,Davis Energy Group | Gray J.P.,Davis Energy Group
Power | Year: 2012

Sound energy policy is critical to enhancing employment opportunities. Public policy and investments advancing renewable energy must be based on sound economics. Regulators have discriminated against out-of-state renewable resources, rationalizing that such exclusionary practices will promote in-state green jobs. Promises and claims of green job creation ignore the fundamental economics of the energy industry. Energy production is capital intensive regardless of the fuel selected to generate power. Construction of a renewable power plant creates construction jobs and the associated multiplier effects in the local economy. However, these benefits are transitory and undistinguishable from the short-term stimulus any large-scale infrastructure project. In addition, green power plants offer only a minute number of long-term employment opportunities. The commercial growth of renewable power is expected to serve as a catalyst for employment in the development and manufacturing of the technological and physical components of generating facilities. However, there is no reason that these employment gains will be in geographic areas proximate to the renewable generation. The US will attract and retain jobs for producing wind turbines and solar panels based on the same economically circumstances that make the country attractive or unattractive for the production of silicon chips and mobile phones. The fact that a job is created by the green economy will not, by itself, overcome the cost, educational, and regulatory impediments that are inhibiting domestic employment in other technological areas.


Hoeschele M.A.,Davis Energy Group | Weitzel E.,Davis Energy Group
ASHRAE Transactions | Year: 2013

Residential gas water heating is a significant end use in many homes, exceeding gas space heating in many milder climates such as California's. Efficiency options exist in improving water heating system performance by reducing hot-water loads, improving distribution systems, and improving the operating efficiency of the water heater. This paper explores the monitored performance of both existing atmospheric gas storage water heaters and advanced gas water heaters in 18 California homes. Findings indicate that significant savings can be achieved with advanced storage and tankless technologies, although high current costs, especially in retrofit applications, contribute to overall marginal economics. © 2013 ASHRAE.


Greenwald S.F.,Davis Energy Group | Gray J.P.,Energy Practice Group
Power | Year: 2010

A discussion on renewables covers the survival and expansion of legislatively mandated renewable energy requirements, tax incentives, and outright subsidies through the recent economic downturn, challenges related to the development of new fossil-fueled generation projects; the need for new fossil-fueled generation; the need for transmission grid operators to integrate new intermittent renewable resources without compromising system and local reliability; access to credit and capital markets; realizing reductions in greenhouse gas emissions; and technological advancements.


Shea K.E.,Davis Energy Group | Gelardi M.J.,Davis Energy Group
Power | Year: 2010

The EPA issued a rule creating a mandatory national system for reporting greenhouse gas (GHG) emissions. The agency requires regulated entities to begin monitoring GHG emissions on 1/1/2010, and to submit their first annual emissions on 3/31/2011. The EPA's program covers ≈ 10,000 factories, power plants, fuel suppliers, and other business units accounting for about 85% of national GHG emissions. The rule requires monitoring and reporting of all major GHG, including CO 2, CH 4, NO, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and other fluorinated gases. Those required to report include not only large "downstream" facilities that directly emit GHG but also "upstream" suppliers of GHG-producing fuels and chemicals, plus certain vehicle and engine manufacturers dubbed "mobile" sources.


Patent
Davis Energy Group | Date: 2011-04-06

A device is provided for managing air flow in an air handling system. The device has a first movable air deflector and a separate second movable air deflector, each of which are movable between a first position and a second position. A linkage assembly is provided connecting the first movable air deflector and the second movable air deflector. The linkage assembly has a single actuator and is further configured to cooperatively move the first movable air deflector and the second movable air deflector between the respective first position and the second position for each of the first movable air deflector and the second movable air deflector, and to apply a sealing pressure to establish a substantially airtight seal around the each of the first movable air deflector and the second movable air deflector in the first position, around the first air flow deflector in the second position.

Loading Davis Energy Group collaborators
Loading Davis Energy Group collaborators