Policy Implications for an Optimized Electric Power System Utilizing a National High-Voltage Direct-Current Transmission Network

Transitioning to a low-carbon power sector is critical in mitigating the impacts of climate change. The National Energy with Weather System (NEWS) Simulator, a cost-optimizing model incorporating NOAA's high resolution (13-km, 60-min.) weather data and concurrent hourly electric load, has demonstrated an economically feasible reduction in emissions of up to 80% of 1990 levels by 2030 for the U.S. electric sector. Enabled by a national high-voltage direct-current (HVDC) transmission network, this more efficient and interconnected system utilizes greater geographic scale to support weather-driven renewable energy, such as wind and solar PV, decreasing overall variability in generation, reducing costs, and lowering emissions. The present research highlights some expansions to the NEWS simulator capabilities in efforts to assess a transition from a current regionally divided grid to a national system. We incorporate state political boundaries, current electricity market regions and existing U.S. electric sector policies for renewable energies and greenhouse gas (GHG) emissions to reflect current regulation. The latter contribution includes, but is not limited to, state renewable portfolio standards (RPS), cap-and-trade programs in California's AB 32 legislation and the Northeast's Regional Greenhouse Gas Initiative (RGGI), and federal renewable energy incentives in the production tax credit (PTC) and investment tax credit (ITC). We demonstrate the merits of the proposed national HVDC transmission system in terms of renewable energy utilization, electricity costs, GHG emissions, and policy effectiveness under various policy scenarios, and through comparison with regional systems more representative of the current transmission networks. This research analyzes the advanced modeling capabilities within NEWS to provide state- to federal-level data that is critical in achieving high penetration of renewable energy sources and transitioning to a cleaner power sector.