Archive

Affidavit of B.W. Griffiths.

Comments.

Comments (Nov 7, 2022; Aug 24, 2023).

Protest of LS Power Development.

In support of the NEPOOL-approved proposal; report on revenues available to energy storage, filed as part of NEPOOL comments.

On the calculation of marginal distribution costs.

Affidavit filed as part of NEPOOL comments; Answer of the MA AGO.

Mass AGO (M. Hoffer, R. Tepper, B.W. Griffiths, &c.) and the Regulatory Assistance Project.

Presented to the NEPOOL Markets Committee.

Affidavit of B.W. Griffiths.

Synapse Energy Economics (P. Knight et al.), Resource Insight (P. Chernick, B.W. Griffiths), et al., for the AESC Study Group.

P. Chernick and B.W. Griffiths; filed by the Nova Scotia Consumer Advocate.

R. Hornby, P. Chernick, D. White, et al. (incl. B.W. Griffiths). Synapse Energy Economics for the AESC Study Group.

P. Chernick and B.W. Griffiths; review of AEPCO's comments for the Sierra Club.

Time-of-use (“TOU”) electricity rates are challenging to design and results often rely on a regulator’s subjective sense of reasonableness. Here, I describe an objective method to develop TOU rates using optimization techniques. The method identifies rates which minimize the difference between TOU and hourly costs, thereby ensuring rates are efficient and cost based. The technique also enables direct comparison of competing designs. I conclude by demonstrating how this methodology could be applied in practice.

Clean Peak Standards (“CPS”) have been proposed as a method to better align renewable generation with periods of higher electricity demand and higher emissions, by requiring that a percentage of peak period demand be met with renewables or clean-charged energy storage. Proponents argue that CPS can reduce costs, reduce emissions, and improve market efficiency. Using a production-cost and capacity-expansion optimization model, we assess how CPS may affect wholesale market outcomes. We parameterize the model to approximate the New England system, and we test combinations of CPS and Renewable Portfolio Standards (RPS) that reflect needs into the 2040s. In some instances, we find that CPS are ineffective and expensive; in others, we observe that CPS make the grid dirtier and more expensive. CPS offer de minimis reductions in production costs (less than 1%), suggesting efficiency is not improved. Depending on formulation, CPS lead to modest increases in carbon emissions (less than 2%), or modest reductions. Reductions, when present, come at high cost: RPS can reduce emissions by 5-10 times more, per dollar spent. Despite the paucity of benefits, CPS increase system costs (less than 5%). These results suggest that regulators can achieve similar market and environmental outcomes, at lower cost, if they simply do not implement CPS.

B.W. Griffiths. Energy Policy, Vol. 129, June 2019, pp. 481–490. Minimizing retail electricity costs via demand charge management and energy arbitrage is a common application of behind-the-meter energy storage systems (ESS). Research suggests that ESS tend to increase grid emissions, but some speculate that retail rate design could lessen its impact. This paper tests that theory. In this analysis, we pair five years of historic data from ISO New England (ISO-NE) and the PJM Interconnection with 15 commercial building load profiles to reveal how different rate designs influence emissions from ESS used for bill minimization. We find that rate design can be used to lessen the emissions impact of ESS in some markets and reduce net system emissions in others. In ISO-NE, rate design can be used to generate significant reductions in net system emissions. In PJM, emissions from the cleanest rate design are half as numerous as those from the dirtiest. Demand charges and energy charges offer multiple mechanisms to reduce ESS induced emissions. Minimizing different types of demand charges requires different quantities of dispatch from ESS: some demand charges can be minimized by ESS in just a few hours while others require discharge on many days. Real-time energy charges increase dispatch compared to flat energy charges because the ESS is used for both demand charge management and energy arbitrage (flat tariffs preclude energy arbitrage). Separately, real-time energy charges reduce emissions per MWh-stored compared to flat charges because the real-time rates exploit the positive correlation between marginal price and marginal emissions in the wholesale markets we study. A particular rate design that minimizes emissions in one market may increase emissions in another. This confounds the creation of universal solutions and instead highlights the need for approaches tailored to a specific energy market. P.S., I also learned how to make linear programs using python, pyomo, & GLPK which is pretty neat.

M.S. thesis, University of Texas at Austin (co-winner, program best-thesis award). In this paper, I explore varying system resource mixes and energy storage system operational modes that enable carbon-neutral, or carbon-reducing, usage. Specifically, I model the carbon emissions induced by energy storage operated in three ways – energy arbitrage (EA), demand charge management (DCM), and carbon minimization (MinCO2) – in 16 simulated electricity systems where wind and solar assets generate 17% to 81% of annual energy. Dispatch of a 1MW/4MWh battery is simulated for each operational mode and in each resource scenario (for a total of 64 combinations). I find that energy storage is carbon-neutral, or carbon-reducing, in systems generating 17% to 40% of annual energy from renewables, depending on operational mode. P.S., I also learned how to make some great looking charts and graphs.

B.W. Griffiths, C.W. King, G. Gülen, J.S. Dyer, D. Spence, R. Baldick. White Paper UTEI/2018-1-1.

B.W. Griffiths, G. Gülen, J.S. Dyer, D. Spence, C.W. King. White Paper UTEI/2016-11-3.

Successive presentations to the NEPOOL Markets Committee: April, September, October & November 2025.

Successive presentations to the NEPOOL Markets Committee: November 2023 – January 2024.

Presentations to the NEPOOL Markets Committee: April 2023.

B.W. Griffiths. Successive presentations to the NEPOOL Markets Committee: July 2022 – April 2023.

Mass AGO teach-in on ISO-NE, NEPOOL & wholesale power markets.

MA DPU Docket 20-69 technical sessions.

Successive presentations to the NEPOOL Markets Committee: September–November 2020.

B.W. Griffiths and C. Belew. (1) Eliminate the Replacement Energy Reserve; (2) add a lookback provision. Successive presentations to the NEPOOL Markets Committee: September 2019 – March 2020.

London Economics International and the Mass AGO.