Owners and operators of non-residential facilities are considering the use of on-site electrical storage or photovoltaic (PV) generation to reduce their carbon emissions and energy costs. When doing so, however, it is difficult to determine which options (or combination of options) are the most efficient and cost-effective. Vendors can help, but they are unlikely to offer an unbiased presentation of the technical and economic benefits of their products.
To simplify the decision and provide an independent voice, Michael Stadler, of Lawrence Berkeley National Laboratory's (Berkeley Lab) Environmental Energy Technologies Division (EETD), has developed a web-based tool that helps building owners, operators, and managers determine not only their optimal energy system, but also how best to operate it.
Users can access the Storage Viability and Optimization Web Service (SVOW) for free by secure remote login and create a profile of their unique situation, specifying factors such as electrical load profile, local tariff, available technologies, and solar radiation at the site. This can be done using predefined inputs or by providing their own data.
"For example," says Stadler, "the current version contains California tariffs because the project was funded by the California Energy Commission's PIER Program, but a user could also define a tariff for his or her site. Users can define all of the parameters specifically if they want."
Once the selections have been made, SVOW analyzes the data and produces a table detailing an optimal combination of utility electricity purchase, installed on-site generation, and storage, in terms of cost, capacity, and carbon emissions. An accompanying graph shows an optimal operating schedule for a user-selected month and time range, identifying the best times for each technology to provide electricity. The results help users decide whether or not to pursue electric storage or PV options further.
The SVOW's analysis is performed by Berkeley Lab's almost technology-neutral Distributed Energy Resources Customer Adoption Model (DER-CAM), a mixed-integer linear program (MILP) written and executed in the General Algebraic Modeling System (GAMS™) optimization software (more information can be found at the Microgrids at Berkeley Lab website).
Although currently SVOW includes only electrical storage and PV technologies, Stadler is already working on an extension to include fuel cells and other combined heat and power (CHP) technologies likely to be used in non-residential facilities. "There are a number of other promising technologies we could include," he says, "and we'd like to add those to the mix."
In addition to the PIER Program, the project was sponsored by the U.S. Department of Energy.