Travis Simpkins

REopt: A Platform for Energy System Integration and Optimization

REopt is NRELs energy planning platform offering concurrent, multi-technology integration and optimization capabilities to help clients meet their cost savings and energy performance goals. The REopt platform provides techno-economic decision-support analysis throughout the energy planning process, from agency-level screening and macro planning to project development to energy asset operation. REopt employs an integrated approach to optimizing a site?s energy costs by considering electricity and thermal consumption, resource availability, complex tariff structures including time-of-use, demand and sell-back rates, incentives, net-metering, and interconnection limits. Formulated as a mixed integer linear program, REopt recommends an optimally-sized mix of conventional and renewable energy, and energy storage technologies; estimates the net present value associated with implementing those technologies; and provides the cost-optimal dispatch strategy for operating them at maximum economic efficiency. The REopt platform can be customized to address a variety of energy optimization scenarios including policy, microgrid, and operational energy applications. This paper presents the REopt techno-economic model along with two examples of recently completed analysis projects.

Optimal sizing of a solar-plus-storage system for utility bill savings and resiliency benefits

Solar-plus-storage systems can achieve significant utility savings in behind-the-meter deployments in buildings, campuses, or industrial sites. Common applications include demand charge reduction, energy arbitrage, time-shifting of excess photovoltaic (PV) production, and selling ancillary services to the utility grid. These systems can also offer some energy resiliency during grid outages. It is often difficult to quantify the amount of resiliency that these systems can provide, however, and this benefit is often undervalued or omitted during the design process. We propose a method for estimating the resiliency that a solar-plus-storage system can provide at a given location. We then present an optimization model that can optimally size the system components to minimize the lifecycle cost of electricity to the site, including the costs incurred during grid outages. The results show that including the value of resiliency during the feasibility stage can result in larger systems and increased resiliency.

A statistical analysis of the economic drivers of battery energy storage in commercial buildings

There is significant interest in using battery energy storage systems (BESS) to reduce peak demand charges, and therefore the life cycle cost of electricity, in commercial buildings. This paper explores the drivers of economic viability of BESS in commercial buildings through statistical analysis. A sample population of buildings was generated, a techno-economic optimization model was used to size and dispatch the BESS, and the resulting optimal BESS sizes were analyzed for relevant predictor variables. Explanatory regression analyses were used to demonstrate that, of the variables considered, peak demand charges are the most significant predictor of an economically viable battery, and that the shape of the load profile is the most significant predictor of the size of the battery.

Potential Reductions in Emissions and Petroleum Use in Transportation: Perspectives from the Transportation Energy Futures Project

The use of energy-efficient technologies and renewable energy sources in transportation could reduce petroleum use and greenhouse gas emissions, but these approaches may face challenges in consumer adoption, infrastructure requirements, and resource constraints. The Transportation Energy Futures project of the U.S. Department of Energy reviewed opportunities for significant reductions in petroleum use and greenhouse gas emissions. On the basis of that review, a diverse set of strategies is explored: reduced energy intensity of transportation modes, lower use intensity of motorized transport, and reduced carbon or petroleum intensity through the use of electricity and hydrogen from renewable energy as well as the use of biofuels. Energy efficiency and demand-side approaches could stop the growth in total transportation energy. In the light-duty vehicle sector, growth in energy use already is projected to flatten; the deployment of technologies for energy efficiency could limit growth in the non-light-duty sector. Travel reduction and built environment changes could moderate personal transportation demand. Freight mass reductions and mode switching could slow or stabilize freight demand. Vehicles using electricity or hydrogen could enable access to renewable energy resources other than biomass. Challenges in fueling infrastructure expansion and market uptake of advanced vehicles are considered. Competition for biomass also is explored, considering markets for electricity, gasoline, diesel, jet fuel, and bunker fuel. The potential for the implementation of these strategies to displace U.S. petroleum use and reduce greenhouse gas emissions in the transportation sector is discussed along with the barriers to realizing this potential in the market.