More Like this

1. Was it worthwhile? Where have the benefits of rooftop solar photovoltaic generation exceeded the cost?

   https://doi.org/10.1088/1748-9326/aa815e  

   Vaishnav, Parth ; Horner, Nathaniel ; Azevedo, Inês L. ( September 2017 , Environmental Research Letters)

   We estimate the lifetime magnitude and distribution of the private and public benefits and costs of currently installed distributed solar PV systems in the United States. Using data for recently-installed systems, we estimate the balance of benefits and costs associated with installing a non-utility solar PV system today. We also study the geographical distribution of the various subsidies that are made available to owners of rooftop solar PV systems, and compare it to distributions of population and income. We find that, after accounting for federal subsidies and local rebates and assuming a discount rate of 7%, the private benefits of new installations will exceed private costs only in seven of the 19 states for which we have data and only if customers can sell excess power to the electric grid at the retail price. These states are characterized by abundant sunshine (California, Texas and Nevada) or by high electricity prices (New York). Public benefits from reduced air pollution and climate change impact exceed the costs of the various subsidies offered system owners for less than 10% of the systems installed, even assuming a 2% discount rate. Subsidies flowed disproportionately to counties with higher median incomes in 2006. In 2014, the distribution of subsidies was closer to that of population income, but subsidies still flowed disproportionately to the better-off. The total, upfront, subsidy per kilowatt of installed capacity has fallen from $5200 in 2006 to $1400 in 2014, but the absolute magnitude of subsidy has soared as installed capacity has grown explosively. We see considerable differences in the balance of costs and benefits even within states, indicating that local factors such as system price and solar resource are important, and that policies (e.g. net metering) could be made more efficient by taking local conditions into account.

    

   more » « less
2. Inequality in air pollution mortality from power generation in India

   https://doi.org/10.1088/1748-9326/aca8bb  

   Sengupta, Shayak ; Thakrar, Sumil K. ; Singh, Kirat ; Tongia, Rahul ; Hill, Jason D. ; Azevedo, Ines M. L. ; Adams, Peter J. ( December 2022 , Environmental Research Letters)

   India’s coal-heavy electricity system is the world’s third largest and a major emitter of air pollution and greenhouse gas emissions. Consequently, it remains a focus of decarbonization and air pollution control policy. Considerable heterogeneity exists between states in India in terms of electricity demand, generation fuel mix, and emissions. However, no analysis has disentangled the expected, state-level spatial differences and interactions in air pollution mortality under current and future power sector policies in India. We use a reduced-complexity air quality model to evaluate annual PM_2.5mortalities associated with electricity production and consumption in each state in India. Furthermore, we test emissions control, carbon tax, and market integration policies to understand how changes in power sector operations affect ambient PM_2.5concentrations and associated mortality. We find poorer, coal-dependent states in eastern India disproportionately face the burden of PM_2.5mortality from electricity in India by importing deaths. Wealthier, high renewable energy states in western and southern India meanwhile face a lower burden by exporting deaths. This suggests that as these states have adopted more renewable generation, they have shifted their coal generation and associated PM_2.5mortality to eastern areas. We also find widespread sulfur emissions control decreases mortality by about 50%. Likewise, increasing carbon taxes in the short term reduces annual mortality by up to 9%. Market reform where generators between states pool to meet demand reduces annual mortality by up to 8%. As India looks to increase renewable energy, implement emissions control regulations, establish a carbon trading market, and move towards further power market integration, our results provide greater spatial detail for a federally structured Indian electricity system.

    

   more » « less
3. The extent of vegetation-driven panel cooling and consequent increase in electricity generation from solar PV sites depend on climate and soil properties

   Bertel, R. ; Choi, C. S. ; Macknick, J. ; McCall, J. ; Ravi, S ( December 2021 , AGU 2021 Fall Meeting Meeting New Orleans, LA)

   Co-locating solar photovoltaics (PV) with agriculture or natural vegetation could provide a sustainable solution to meeting growing food and energy demands, particularly considering the recent concerns of solar PV encroaching on agricultural and natural areas. However, the identification and quantification of the mutual interactions between the solar panels and the underlying soil-vegetation system are scarce. This is a critical research gap, as understanding these feedbacks are important for minimizing environmental impacts and for designing resource conserving and climate-resilient food-energy production systems. We monitored the microclimate, soil moisture distribution, and soil properties at three utility-scale solar facilities (MN, USA) with different site management practices, with an emphasis on verifying previously hypothesized vegetation-driven cooling of solar panels. The microclimatic variables (air and soil temperature, relative humidity, wind speed and direction) and soil moisture were significantly different between the PV site with bare soil (bare-PV) and vegetated PV (veg.-PV) site. Compared to the bare-PV site, the veg.-PV site also had significantly higher levels of total soil carbon and total soil nitrogen, as well as higher humidity and lower air and soil temperatures. Further, soil moisture heterogeneity created by the solar panels was homogenized by vegetation at the veg.-PV sites. However, we found no significant panel cooling or increase in electricity output that could be linked to co-location of the panels with vegetation in these facilities. We link these outcomes to the background climatic conditions (not water limited system) and soil moisture conditions. In regions with persistent high soil moisture (more frequent rainfall events) soil evaporation from wet bare soil may be comparable or even higher than from a vegetated surface. Thus, the cooling effects of vegetation on solar panels are not universal but rather site-specific depending on the background climate and soil properties. Regardless, the other co-benefits of maintaining vegetation at solar PV sites including the impacts on microclimate, soil moisture distribution, and soil quality support the case for solar PV–vegetation co-located systems. 

   more » « less
4. Exploring sustainable electricity system development pathways in South America’s MERCOSUR sub-region

   Chowdhury, A.F.M. Kamal ( September 2023 , Energy strategy reviews)

   We explore sustainable electricity system development pathways in South America’s MERCOSUR sub-region under a range of techno-economic, infrastructural, and policy forces. The MERCOSUR sub-region includes Argentina, Brazil, Chile, Uruguay, and Paraguay, which represent key electricity generation, consumption, and trade dynamics on the continent. We use a power system planning model to co-optimize investment and operations of generation, storage, and transmission facilities out to 2050. Our results show that, under business-as-usual conditions, wind and solar contribute more than half of new generation capacity by 2050, though this requires substantial expansion of natural gas-based capacity. While new hydropower appears to be less cost-competitive, the existing high capacity of hydropower provides critically important flexibility to integrate the wind and solar and to avoid further reliance on more expensive or polluting resources (e.g., natural gas). Over 90% emission cut by 2050 could be facilitated mostly by enhanced integration (predominantly after 2040) of wind, solar, and battery storage with 11%–28% additional cost, whereas enhanced expansion of hydropower reduces the cost of low-carbon transition, suggesting trade-off opportunities between saving costs and environment in selecting the clean energy resources. Achieving high emission reduction goals will also require enhanced sub-regional electricity trade, which could be mostly facilitated by existing interconnection capacities. 

   more » « less
5. Leveraging federalism for flexible and robust management of social‐ecological systems

   https://doi.org/10.1002/pan3.10458  

   Sims, Charles ; Armsworth, Paul R. ; Blackwood, Julie ; Fitzpatrick, Ben ; Kling, David M. ; Lenhart, Suzanne ; Neubert, Michael ; Papeş, Monica ; Sanchirico, James ; Shea, Katriona ; et al ( February 2023 , People and Nature)

   Managing social‐ecological systems (SES) requires balancing the need to tailor actions to local heterogeneity and the need to work over large areas to accommodate the extent of SES. This balance is particularly challenging for policy since the level of government where the policy is being developed determines the extent and resolution of action.

   We make the case for a new research agenda focused on ecological federalism that seeks to address this challenge by capitalizing on the flexibility afforded by a federalist system of governance. Ecological federalism synthesizes the environmental federalism literature from law and economics with relevant ecological and biological literature to address a fundamental question: What aspects of SES should be managed by federal governments and which should be allocated to decentralized state governments?

   This new research agenda considers the bio‐geo‐physical processes that characterize state‐federal management tradeoffs for biodiversity conservation, resource management, infectious disease prevention, and invasive species control.

   Read the freePlain Language Summaryfor this article on the Journal blog.

    

   more » « less