Access to electricity is widely recognized as an important factor for economic and social development. Low rates of access, particularly in remote rural areas in regions such as sub-Saharan Africa, ...South Asia, and Southeast Asia, have led developing nations and international organizations to set ambitious goals to expand the reach of electricity. Decentralized solutions such as microgrids have been proposed as cost effective solutions to reaching communities located far from central grid infrastructure. Lack of capital from public and donor sources has severely impeded achieving access goals, leading to calls for greater private sector participation in electrification activities. However, due to the high level of risk associated with decentralized electrification projects in low-income areas, marginal expected returns on investment, and a lack of clear and effective public policy, the private sector has not shown significant interest in participating in such projects. The purpose of this paper is to review barriers to private sector participation in decentralized electrification projects and to identify solutions that have been implemented and proposed to overcome these barriers. The barriers discussed include unsecure revenue streams, inability to finance projects, and long-term project risks such as grid encroachment. The range of interventions and business models reviewed include methods to secure reliable demand, subsidy models, risk guarantees, and different revenue models. This paper does not include an analysis of the effectiveness of the different interventions described. Future research should evaluate the relative costs and benefits of these interventions in order to provide robust policy guidance to decision makers in developing countries.
Installations of rooftop solar photovoltaic (PV) technology in the United States have increased dramatically in recent years, in large part because of state and federal subsidies. In the future, such ...subsidies may be reduced or eliminated. From the homeowner's perspective, solar PV is competitive when it can produce electricity at a cost equivalent to the retail electricity rate, a condition sometimes referred to as “socket parity”. In assessing the economic viability of residential solar PV, most existing literature considers only a few locations and fails to consider the differences in PV system cost and electricity prices that exist across the U.S. We combined insolation data from more than 1000 locations, installation costs by region, and county-level utility rates to provide a more complete economic assessment of rooftop solar PV across the U.S. We calculated the break-even electricity prices and evaluated the reductions in installed costs needed to reach socket parity. Among the scenarios considered, we estimate that only Hawaii has achieved socket parity without the use of subsidies. With subsidies, six states reach socket parity, yet widespread parity is still not achieved. We find that high installation costs and financing rates are two of the largest barriers to socket parity.
•We evaluate the economic viability of residential rooftop solar PV across the U.S.•Widespread socket parity has not been achieved in the U.S. without subsidies.•Net metering may be critical for the economic viability of rooftop solar PV.
Industrial poultry production is a resource-intensive activity due to specific indoor temperature requirements to ensure optimal chicken growth. The energy consumption to maintain this ideal ...microclimate demands substantial operating expenses that are subject to climate conditions. As such, energy demand for heating and cooling (HVAC) for commercial broiler chicken production may be influenced by increased temperatures that occur due to climate change. This study focuses on evaluating the effects of climate change on future HVAC demands in a typical commercial broiler house in the Eastern U.S. To estimate such demands, we developed a simplified thermodynamic model that uses downscaled air temperature as input. These inputs stemmed from twenty General Circulation Models (GCM) for business-as-usual (RCP 8.5) and moderate (RCP 4.5) climate change scenarios. Our results indicate that increased temperatures from climate change scenarios by mid-century will increase energy demand for cooling by 5.5 ± 1.8% (RCP 4.5) and 6.6 ± 2.1% (RCP 8.5), and reduce energy demand for heating by 9.0 ± 3.2% (RCP 4.5) and 10.3 ± 3.7% (RCP 8.5) with respect to 2018. Furthermore, our results suggest that warmer temperatures under climate change will substantially increase water withdrawals for evaporative cooling. However, there may be a point where cooling pads may not be efficient enough to cool down chickens and other innovative alternatives may be required. Such changes could include the use of air conditioning units, which would further increase electricity demand. Efficiency improvements that could mitigate some of the negative changes in energy demand could include increasing the size of the house, modifying the production schedule to minimize energy use, and adding insulation.
•Climate change increased temperatures may increase cooling energy demand and reduce heating energy demand in broiler barns.•Reductions in energy demand for heating outweigh increased energy demand for cooling.•Warmer temperatures from RCP 8.5 could substantially increase water withdrawals for evaporative cooling beyond 2050.•Increasing the size of houses and adding insulation may help mitigate energy demand variability across the “Broiler Belt”.
Over the last decade there have been a growing number of federal and state regulations aimed at controlling air emissions at power plants and/or increasing the penetration of renewable resources in ...the grid. Environmental Protection Agency regulations will likely lead to the retrofit, retirement, or replacement of coal-fired power plants while the state Renewable Portfolio Standards will continue to drive large-scale deployment of renewable energy sources, primarily wind. Combined, these changes in the generation fleet could have profound implications for the operations of the power system. In this paper, we aim to better understand the interaction between coal plant retirements and increased levels of wind power. We extensively analyze the operations of the PJM electricity system under a broad set of scenarios that include varying levels of wind penetration and coal plant retirements. Not surprisingly, we find that without transmission upgrades, retirement of coal-fired power plants will likely result in considerable transmission congestion and higher energy prices. Increased wind penetration, with high geographic diversity, could mitigate some of the negative effects of coal plant retirement and lead to a significant reduction in air emissions, but wind forecast error might impose operational constraints on the system at times of peak load.
•Retirement of coal plants may increase transmission congestion and LMP prices.•EPA rules might lead to significant reductions in emission of air pollutants.•Wind geographical diversity may reduce transmission constraints and air emissions.•At times of high peak load, wind may not reduce system stress caused by retirement.•RPS policies can support and mitigate negative impacts of EPA regulations.
Interest in biobased products has been motivated, in part, by the claim that these products have lower life cycle greenhouse gas (GHG) emissions than their fossil counterparts. This study ...investigates GHG emissions from U.S. production of three important biobased polymer families: polylactic acid (PLA), polyhydroxybutyrate (PHB) and bioethylene-based plastics. The model incorporates uncertainty into the life cycle emission estimates using Monte Carlo simulation. Results present a range of scenarios for feedstock choice (corn or switchgrass), treatment of coproducts, data sources, end of life assumptions, and displaced fossil polymer. Switchgrass pathways generally have lower emissions than corn pathways, and can even generate negative cradle-to-gate emissions if unfermented residues are used to coproduce energy. PHB (from either feedstock) is unlikely to have lower emissions than fossil polymers once end of life emissions are included. PLA generally has the lowest emissions when compared to high emission fossil polymers, such as polystyrene (mean GHG savings up to 1.4 kg CO2e/kg corn PLA and 2.9 kg CO2e/kg switchgrass PLA). In contrast, bioethylene is likely to achieve the greater emission reduction for ethylene intensive polymers, like polyethylene (mean GHG savings up to 0.60 kg CO2e/kg corn polyethylene and 3.4 kg CO2e/kg switchgrass polyethylene).
Access to electricity is a key enabler of social and economic development. However, 1.2 billion people still do not benefit from reliable electricity services. Microgrids have been proposed as a ...cost-effective means to accelerate access for communities located far from existing grid infrastructure. Scarcity of capital has been a barrier to both on-grid and off-grid electrification efforts and governments have sought private sector participation in an effort to close this gap. There is a lack of quantitative analysis to critically evaluate the key drivers of risk in microgrid utilities, or how different business models and technologies affect the potential for these projects to attract finance and scale up deployment. This paper introduces the Stochastic Techno-Economic Microgrid Model (STEMM), which enables assessment of the effect of technical design decisions as well as financial conditions on the financial viability of microgrid projects from an investment perspective. Using STEMM, this paper presents a risk analysis of the key uncertain variables affecting microgrid investments to both debt and equity investors using four technology scenarios as case studies in Rwanda. We find that major contributors to risk are fuel price volatility, uncertain electricity demand, and foreign exchange risk for investments in hard currency. Choice of technology strongly influences the risk profile of microgrids, with solar powered microgrids susceptible to demand uncertainty and diesel-based systems exposed to fuel price volatility. Hybrid solutions provide a middle ground with partial mitigation of both fuel price and demand risk. If electricity tariffs are linked to changes in fuel price, fuel price risk can be effectively passed to consumers.
Pollution from oil spills can seriously affect many ecosystem processes and human health. Many articles have evaluated the impact of oil spills on human health. However, most of these articles focus ...on occupational exposure. The effect on people living in the areas affected by oil pollution is rarely studied. Approximately 640 million people worldwide live in areas at risk of oil pollution. Thus, studying the impact of this pollution on human health should be a priority. Here, we evaluate the presence of anemia in relation to crude oil exposure in men living in areas at risk of oil contamination in the Ecuadorian Amazon (Orellana and Napo). We evaluated the hematological and biochemical parameters of 135 participants. We divided the participants into three groups according to exposure: low, medium, and high. Our results showed a significant association between exposure risk and hemoglobin and hematocrit concentration. Groups with medium- and high- contamination exposure had levels below normal values in hemoglobin and hematocrit in more than 30% and 26% of the population, respectively. In conclusion, we found that crude oil affected human health, and the prevalence of the anemia in men was dependent of the level of contamination.
Display omitted
•Biochemical and hematological parameters were analyzed of population of Amazon of Ecuador.•A relationship between exposure to crude oil and anemia in men was observed.•GLM did not show effects on monocytes, granulocytes, lymphocytes, or red blood cells.•OR significant effects of the level of risk on hematocrit were evidenced.
Mini-grids are the lowest-cost solutions for electrifying many homes and businesses in rural communities with low energy access. Estimates of the electricity demand of unelectrified customers are a ...crucial input to selecting mini-grid sites, projecting revenue, and sizing system components to provide adequate capacity while minimizing capital costs. Typical customer survey-based demand estimates for these communities — where there are no historical data — are not reliable, typically overpredicting demand. Here, we test a data-driven approach to demand prediction using survey and smart meter data from 1378 Tanzanian mini-grid customers. We found that models incorporating customer survey data into their predictions consistently out-performed a baseline model that did not. Our best-performing model, the LASSO, predicted daily electricity demand with a median absolute error of 66% and 37% for individual connections and mini-grid sites, respectively. Quantitative measures of variable importance show that most survey data are not useful for estimating demand. These results suggest that surveys should prioritize thorough inventories of prospective customers' currently-owned appliances instead of detailed demographic information or self-reported habits and plans. Pairing shortened questionnaires with smart meter data from preexisting mini-grids can improve estimates of initial customer electricity demand significantly compared to standard field practices.
•Data-driven methods improve estimates of off-grid electricity demand.•Combining customer surveys, smart meters and machine learning most effective•We predict community electricity demand over 14 sites at 37% median absolute error.•Can inform mini-grid site selection, revenue projection, and system sizing
The generation and distribution of electricity comprises nearly 40% of U.S. CO2 emissions, as well as large shares of SO2, NO x , small particulates, and other toxins. Thus, correctly accounting for ...these electricity-related environmental releases is of great importance in life cycle assessment of products and processes. Unfortunately, there is no agreed-upon protocol for accounting for the environmental emissions associated with electricity, as well as significant uncertainty in the estimates. Here, we explore the limits of current knowledge about grid electricity in LCA and carbon footprinting for the U.S. electrical grid, and show that differences in standards, protocols, and reporting organizations can lead to important differences in estimates of CO2, SO2, and NO x emissions factors. We find a considerable divergence in published values for grid emissions factor in the U.S. We discuss the implications of this divergence and list recommendations for a standardized approach to accounting for air pollution emissions in life cycle assessment and policy analyses in a world with incomplete and uncertain information.
Display omitted
•We estimate on-road traffic emissions for Bogotá using a traffic assignment model.•Private cars are the main contributors accounting for 60% CO and SO2 emissions.•Old vehicles ...without catalytic converter technology are high emitters.•Transit buses and BRT, combined, account for 7% of PM10 emissions.•Local street traffic accounts for 15%–25% of CO, SO2, VOC, NOx, PM10 emissions.
This paper presents a traffic-related air emissions inventory of a developing megacity using a traffic assignment model that results in a detailed temporal and spatial emission representation, disaggregating emissions sources by vehicle type and hour of the day, for five criteria air pollutants.
PDF
