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With an increasing number of jurisdictions considering alternatives to net metering policies to financially compensate behind-the-meter solar photovoltaics (PV), customer economics will increasingly depend on its ability to reduce demand charges. Understanding these demand charge savings from PV—and how behind-the-meter storage can potentially enhance those savings—is essential to understand PV market dynamics and adoption in the coming years. This article explores how these demand charge savings vary with demand charge designs and customer load profiles, modeled for a variety of residential and commercial customers. Our findings indicate that demand charge savings are lowest under a basic, non-coincident demand charge design where the demand charge is based on the maximum demand level over the month, regardless of timing, resulting primarily from the temporal mismatch between the timing of the PV host's demand peak and PV generation. PV provides greater demand charge savings, for both commercial and residential customers, when demand charge designs are based on predefined, daytime peak periods or longer averaging intervals. Demand charge savings from PV combined with storage are almost always greater than the sum of the savings attained through either technology separately. We also explore how well demand charge savings from PV align with corresponding utility savings.

Demand charges, which are based on a customer’s maximum demand in kilowatts (kW), are a common element of electricity rate structures for commercial customers. Customer-sited solar photovoltaic (PV) systems can potentially reduce demand charges, but the level of savings is difficult to predict, given variations in demand charge designs, customer loads, and PV generation profiles. Lawrence Berkeley National Laboratory (Berkeley Lab) and the National Renewable Energy Laboratory (NREL) are collaborating on a series of studies to understand how solar PV can impact demand charges. Prior studies in the series examined demand charge reductions from solar on a stand-alone basis for residential and commercial customers. Those earlier analyses found that solar, alone, has limited ability to reduce demand charges depending on the specific design of the demand charge and on the shape of the customer’s load profile. This latest analysis estimates demand charge savings from solar in commercial buildings when co-deployed with behind-the-meter storage, highlighting the complementary roles of the two technologies. The analysis is based on simulated loads, solar generation, and storage dispatch across a wide variety of building types, locations, system configurations, and demand charge designs.

Renewable portfolio standards (RPS) exist in 29 US states and the District of Columbia. This article summarizes the first national-level, integrated assessment of the future costs and benefits of existing RPS policies; the same metrics are evaluated under a second scenario in which widespread expansion of these policies is assumed to occur. Depending on assumptions about renewable energy technology advancement and natural gas prices, existing RPS policies increase electric system costs by as much as $31 billion, on a present-value basis over 2015-2050. The expanded renewable deployment scenario yields incremental costs that range from $23 billion to $194 billion, depending on the assumptions employed. The monetized value of improved air quality and reduced climate damages exceed these costs. Using central assumptions, existing RPS policies yield $97 billion in air-pollution health benefits and $161 billion in climate damage reductions. Under the expanded RPS case, health benefits total $558 billion and climate benefits equal $599 billion. These scenarios also yield benefits in the form of reduced water use. RPS programs are not likely to represent the most cost effective path towards achieving air quality and climate benefits. Nonetheless, the findings suggest that US RPS programs are, on a national basis, cost effective when considering externalities.

Commercial retail electricity rates commonly include a demand charge component, based on some measure of the customer’s peak demand. Customer-sited solar PV can potentially reduce demand charges, but the magnitude of these savings can be difficult to predict, given variations in demand charge designs, customer loads, and PV generation profiles. Moreover, depending on the circumstances, demand charges from solar may or may not align well with associated utility cost savings.Lawrence Berkeley National Laboratory (Berkeley Lab) and the National Renewable Energy Laboratory (NREL) are collaborating in a series of studies to understand how solar PV can reduce demand charge levels for a variety of customer types and demand charges designs. Previous work focused on residential customs with solar. This study, instead, focuses on commercial customers and seeks to understand the extent and conditions under which rooftop can solar reduce commercial demand charges. To answer these questions, we simulate demand charge savings for a broad range of commercial customer types, demand charge designs, locations, and PV system characteristics. This particular analysis does not include storage, but a subsequent analysis in this series will evaluate demand charge savings for commercial customers with solar and storage.

Glacier contributions to streamflow moderate summer water temperatures and help keep rivers cool during periods of hot, dry weather. As glaciers retreat, the length of channel exposed to solar radiation above a given point of interest would increase, which should ultimately result in higher water temperatures. However, formation of proglacial lakes may complicate river temperature response to glacier retreat. This study examined river and lake temperature response to the retreat of lake‐terminating Bridge Glacier, British Columbia, using a combination of manual spot and continuous river temperatures at a stream gauge, lake surface temperatures derived from Landsat imagery, and in situ lake temperatures made during a field campaign during summer 2013. Temperature data spanned the period from 1984 to 2022. Lake and river temperatures were relatively constant prior to and during a period of rapid retreat, but exhibited an upward trend following 2012, when iceberg density declined due to an apparent decrease in calving rate, resulting in an increase in lake surface area and river temperature of about 5°C even though the glacier remained lake terminating. In addition to providing the first longitudinal study of water temperature response to the retreat of a lake‐terminating glacier, this study adds to a body of literature that demonstrates that routine spot river temperatures, if collected in a consistent manner over a number of years, can provide valid information about river and stream temperature trends. [ABSTRACT FROM AUTHOR]

A new binder- and carbon-free electrode for lithium-ion batteries was prepared using a hierarchically porous Ag-based current collector. The latter was produced by applying the method of selective dissolution of the less noble metals from the Cu60Ag30Al10 master alloy tape. The current collector was reaction-coated with an electrochemically active Ag2S–CuxS coating. The metallic structure provided a mechanically stable conductive scaffold on the walls of which the Ag2S–CuxS skin material was directly deposited. The ordered porosity – hierarchical and directional – provided easy penetration of the liquid electrolyte as well as short Li+ ion diffusion paths. The as-prepared electrodes were tested in a half-cell configuration vs. Li/Li+ at various current rates to study the cycling and rate performances of the electrode. The first cycling capacity of ∼1250 mA h g−1 was measured at 0.4 A g−1 current rate. After a rapid decrease, a stable reversible capacity of ∼230 mA h g−1 was established at a current rate of 0.4 A g−1 (calculated vs. the weight of the incorporated sulphur). Excellent charge/discharge cycling and rate properties were observed for over 1000 cycles at higher rates of 1.0 and 2.0 A g−1, in the potential window of 0.15–2.8 V vs. Li/Li+. The observed cycling stability was ascribed to the mechanism of a "displacement" reaction with Li ions. Additional capacity is also available from alloying–dealloying with Ag (and Cu to some extent) and S redox reactions. These results open up a new opportunity for using a Cu–Ag alloy as the precursor for making electrodes for thin Li-ion and Li–S batteries with high cycling stability at relatively high current rates. [ABSTRACT FROM AUTHOR]

The combination of policies, the vastly improved technologies and a developing market for green power has brought tremendous growth in wind energy generation. The details on the policy drivers like Renewable Portfolio Standards (RPS), as well as market drivers such as consumer demand, of wind markets, invested by the states of United States, are discussed.