Business As Usual Case Research Articles

How does upzoning impact land use and transport: a case study of Seattle

ABSTRACT This work simulates the long-term land use and transportation impacts of upzoning in the region of Seattle, Washington at the parcel level, using UrbanSim and an agent-based travel demand model (SoundCast). Scenario results are compared to illuminate differences in a Business-as-Usual (BAU) future versus two upzoning scenarios that upzone all single-family-use residential parcels in the region or just those in the City of Seattle to 3 dwelling units per parcel. Under BAU, affordability falls 20% and rents rise 6% between 2014 and 2050, as the regional population grows to 5.7 million. With regional upzoning, 68,400 more dwellings are added, with rents 10% lower compared to the BAU future. The housing affordability index falls from 75.3 to 67.31, a significant improvement over the BAU scenario's sharper fall to 60.6. If only the City of Seattle upzones, only 3,400 additional units are predicted, but rents are 5.2% lower than the BAU case.

Energy demand modeling for low carbon cities in Thailand: A case study of Nakhon Ratchasima province

Nakhon Ratchasima is one of the northeastern cities which has been promoted as one of the low-carbon cities in Thailand. The study aims to evaluate policies and measures on greenhouse gas (GHG) emissions mitigation to meet the target at the provincial level. The Low Emissions Analysis Platform (LEAP) is used as a modeling tool to simulate energy demand for each economic sector. The 2019 data is set as a base year, using top-down and bottom-up approaches depending on the availability of data for the analysis. The model consists of two scenarios: (1) Business-as-usual (BAU) scenario and Low carbon scenario (LCS). Transport and industry sectors are the most energy-consuming and CO2-emitting sectors in Nakhon Ratchasima Province. In the LCS case, the final energy demand and CO2 emissions in 2050 will be reduced by about 40% compared to the BAU case. In addition, CO2 emissions in Nakhon Ratchasima Province will peak around 2038, this is not the case with BAU. The study could predict future energy demand and propose a way forward to reducing GHG emissions at the provincial level.

The overarching role of electric vehicles, power‑to‑hydrogen, and pumped hydro storage technologies in maximizing renewable energy integration and power generation in Sub-Saharan Africa

Globally, efforts are underway to keep global warming well below 1.5–2 °C as outlined in the Paris Agreement. Ghana plans to achieve 10 % renewable energy (RE) participation in the national energy mix by 2030. In the Renewable Energy Masterplan 2030, the target is a total installed RE utility scale of 1094.63 MW. In the current work, we propose a better pathway to gradual decarbonization of the Ghanaian energy sector (power, transport, industry, residential, and others) at higher technical levels of variable RE (VRE) penetration, 0 critical excess electricity production (CEEP), and lower cost than the 2030 Business-as-Usual (BAU) scenario. In our proposed scenario, High Renewable Energy Penetration (HREP) 2030, we assess the overarching role of electric vehicle integration, power-to-gas (hydrogen), and pumped hydro storage technologies in maximizing VRE penetration in Ghana. The results from the current study show that it is technically feasible to include solar and wind power penetrations of 32.66 % and 38.11 % in the 2030 HREP scenario compared to the 2.64 % and 1.99 % of the 2030 BAU case, respectively. The HREP scenario will ultimately lead to 26.45, 30.86, and 23.34 % contribution of solar, wind, and thermal in the total electricity production in 2030 compared to the 2.36, 1.78, and 74 % of the BAU scenario, respectively. The CO2 emissions and its cost in the HREP case are 22.5 and 22.81 % lower than in the BAU case, and the total annual cost of the former is 12 % lower than the latter. The total electricity production from wind and solar energy alone in the 2030 HREP will create an additional 723 jobs and 11.96 Mt avoided CO2 emissions. The proposal made in the current study could usher in a long-term transition pathway that leads from the current fossil-based system to an affordable, efficient, sustainable, and secure energy future for Ghana. The findings presented in the current study should be of significance to decision-makers in formulating and adopting zero and low-carbon strategies for long-term decarbonization targets and planning in Ghana beyond 2030.

Evaluation of low-carbon multi-energy options for the future UAE energy system

Sustainable energy transitions in hot climate and fossil energy-rich regions face specific challenges including socio-economic and geopolitical uncertainties in a carbon-constrained future, accompanied by significant vulnerability to climate change. Low-carbon multi-energy conversion, storage and use options for the future United Arab Emirates energy system (power, water, buildings, transportation, industry) are investigated technically and economically using EnergyPLAN energy planning tool. Emphasis is placed on solar energy with variable shares in conjunction with thermal, battery and hydrogen storage in the power sector, reverse osmosis desalination, district cooling with a mix of compression and absorption cooling, electric transportation, and industrial electrification. The effects of these measures on annual primary fuel consumption (PFC), greenhouse gas emissions (GHG) and cost are evaluated in incremental steps, with reference to a business-as-usual (BAU) scenario. The most favorable combination of low-carbon measures is found to reduce annual PFC and GHG emissions by 37% and 48%, respectively, relative to the BAU case. In parallel, total annual costs would reduce by 25% compared to the BAU scenario, primarily due to reductions in fuel and carbon costs, that offset increased investment costs. In addition, the levelized costs of electricity, water and cooling could reduce by 42%, 63%, and 20%, respectively, relative to the BAU case. The analyzes presented contribute directions towards sustainable energy transitions in fossil energy-rich and hot climate regions.

The European forest carbon budget under future climate conditions and current management practices

Abstract. To become carbon neutral by 2050, the European Union (EU27) net carbon sink from forests should increase from the current level of about −360 to −450 Mt CO2eq yr−1 by 2050. Reaching this target requires additional efforts, which should be informed by the expected interactions between current age-class distributions, the effect of forest management practices and the expected impacts of future climate change. However, modelling the combined effect of these drivers is challenging, since it requires a mechanistic assessment of climate impacts on primary productivity and heterotrophic respiration and a detailed representation of the forest age structure and of the management practices across the entire EU. To achieve this goal, we combined the output provided by four land–climate models – run under two different Representative Concentration Pathway scenarios (RCP2.6 and RCP6.0) – to parameterize the input data used in an empirical forest growth model. This hybrid modelling approach aims to quantify the impact of climate change and forest management on the long-term (i.e. to 2100) evolution of the EU27 + UK forest carbon budget. This approach was tested using a business-as-usual (BAU) scenario, based on the continuation of the management practices applied by EU member states within the historical period 2000–2015. We emphasize that our study does not explore a specific policy scenario but describes a methodological framework. Our results highlight that, under our BAU case, the EU27 + UK forest C sink would decrease to about −250 Mt CO2eq yr−1 in 2050 and −80 Mt CO2eq yr−1 by 2100. The main driver of the long-term evolution of the forest C sink is the ongoing ageing process of the European forests, mostly determined by past and ongoing management. In addition, climate change may further amplify or mitigate this trend. Due to the large uncertainty in climate projections, in 2050 the net C sink may range from −100 to −400 Mt CO2eq yr−1 under RCP2.6 and from −100 to −300 Mt CO2eq yr−1 under RCP6.0. These results suggest that while a change in management practices would be needed to reverse an otherwise declining trend in the sink, climate change adds a considerable uncertainty, potentially nearly doubling or halving the sink associated with management.

Potential impacts of electric vehicles on air quality and health endpoints in the Greater Houston Area in 2040

Significant emissions from transportation contribute to the formation of O3 and fine particulate matter (PM2.5), causing poor air quality and health. In this study, four scenarios were developed to understand how future fleet electrification and turnover of both gasoline and diesel vehicles affect air quality and health in the Houston Metropolitan area. These scenarios considered increased vehicle activity and various configurations of emissions controls. Comparing to a base year of 2013, model predictions for 2040 indicated a ∼50% emissions increase in the Business As Usual (BAU) case, and ∼50%, ∼75%, and ∼95% reductions in the three distinct emissions control cases, the Moderate Electrification (ME), Aggressive Electrification (AE), and Complete Turnover (CT) cases, respectively. Each modeling scenario was conducted using a high-resolution (1 km) WRF-SMOKE-CMAQ-BenMAP air quality and health modeling framework, which helped capture urban features in higher detail. The emissions control cases resulted in 1–4 ppb maximum 8 h O3 increase along highways and reductions both in the regions enclosed by the highways and those downwind. Simulated PM2.5 concentrations decreased between 0.5 and 2 μg m−3. Health impact results suggest that increased O3 and PM2.5 concentrations from the BAU case will lead to 122 additional premature deaths with respect to 2013. However, reduced emissions for the control cases (ME, AE, CT) will prevent 114–246 premature deaths. Additionally, about 7,500 asthma exacerbation and 5,500 school loss days will be prevented in the ME case, benefiting younger individuals. The economic benefits generally followed the same trends as health impacts. The analysis framework developed in this study can be applied to other metropolitan areas. The effects of motor vehicle electrification on power plant emissions were estimated using the Argonne National Laboratory's Autonomie data, and indicated the electrification load to be negligible as opposed to projected electricity generation.

The impact of the UK’s emissions reduction initiative on the national food industry

This study aims at determining the technology combination that provides the lowest emissions and energy cost for the food-industrial sector. Using a linear optimization objective function in determining the least-cost pathway, data from various sources were compiled to perform simulations on two scenarios; a business as usual (BAU) case and an 80% greenhouse gas (GHG) emissions reduction. Even in the base case, the emission level reaches 21% of 1990 levels; a reduction of 39% over the simulation period. This indicates that even without the imposition of GHG constraints on the food sector, it is economically more beneficial for the industry to migrate from fossil fuels. This migration takes place by replacing energy from LPG, LFO, Kerosene, HFO, Coal and Natural gas with biomass, biogas and CHP electricity. Economic benefits arise from the fact that biogas and biomass are produced from wastes which are generated onsite within food factories, hence the avoidance of purchasing energy feedstock from the market. The change in energy consumption between the two scenarios is similar due to the prevalence of least-cost solutions and similar energy and food demand requirements. However, the reduction in emissions are greater in the 80%-GHG case than the BAU case; 52% compared to 39% for the BAU case, for 2050 relative to 2010. This is largely owing to decarbonization of grid electricity. This study finds that the food-industrial sector has the potential to exceed this 80% reduction target to a value of 92%, due to the availability of onsite feedstocks to generate biogas. In this simulation, of all waste produced, 92% of waste feedstock is consumed in AD and CHPs, whilst the remaining 8% is dried and processed to be burned in biomass boilers.

On the impacts of carbon tax and technological progress on China

ABSTRACTUsing a dynamic national computable general equilibrium model, we investigate the impact of carbon tax and energy efficiency improvement on the economy and environment of China. The Chinese social account matrix is presented based upon the latest input–output table (2012 IO table) and other data. The business as usual (BAU) scenario is designed according to several forecasts about China by 2030, followed by six policy scenarios, including different levels of carbon tax and technological progress as well as their combinations. The results show that carbon tax will frustrate the overall economic growth slightly. The CO2 emission will be 13.81% lower in 2030 compared to BAU case if the carbon tax scheme is carried out at a rate of 200 RMB/ton of CO2. Technological progress will stimulate the economic growth, enrich the household and government income, increase total investment and make most sectors prosperous with the exception of energy industries.

Modelling to generate alternatives: A technique to explore uncertainty in energy-environment-economy models

In this study we describe a novel formulation of the so-called modelling to generate alternatives (MGA) methodology and use it to explore the near cost optimal solution space of the global energy-environment-economy model TIAM-UCL. Our implementation specifically aims to find maximally different global energy system transition pathways and assess the extent of their diversity in the near optimal region. From this we can determine the stability of the results implied by the least cost pathway which in turn allows us to both identify whether there are any consistent insights that emerge across MGA iterations while at the same time highlighting that energy systems that are very similar in cost can look very different. It is critical that the results of such an uncertainty analysis are communicated to policy makers to aid in robust decision making. To demonstrate the technique we apply it to two scenarios, a business as usual (BAU) case and a climate policy run. For the former we find significant variability in primary energy carrier consumption across the MGA iterations which then projects further into the energy system leading to, for example, large differences in the portfolio of fuels used in and emissions from the electricity sector. When imposing a global emissions constraint we find, in general, less variability than the BAU case. Consistent insights do emerge with oil use in transport being a robust finding across all MGA iterations for both scenarios and, in the mitigation case, the electricity sector is seen to reliably decarbonise before transport and industry as total system cost is permitted to increase. Finally, we compare our implementation of MGA to the so-called Hop-Skip-Jump formulation, which also seeks to obtain maximally different solutions, and find that, when applied in the same way, the former identifies more diverse transition pathways than the latter.

DYNAMIC AIR TOXIC EMISSION FACTOR OF MOTORCYCLES IN BANGKOK, THAILAND

Average emission factors of air toxic compounds, emitted from motorcycles in Bangkok, Thailand were analyzed using the IVE (International Vehicle Emission) model. The model was utilized taking into account the actual fleet and characteristics of motorcycles of the study area. Four air toxic compounds (namely benzene, 1,3 butadiene, acetaldehyde and formaldehyde) and their emission rates were calculated under two main pollution abatement scenarios (the improvement of fuel quality and switching of fuel types). The results were then compared with the BAU (Business as Usual) case to illustrate the effectiveness and appropriateness of proposed measures. In the BAU scenario the average emission factors of air toxics from motorcycles were greatly reduced by the replacement of engine technology from the carburetor system with the electronically controlled fuel injection system. Improvement of fuel quality standard (from EURO II to EURO IV) resulted in a decrease in average emission factors of air toxics from motorcycles. Calculated results indicated that the average emission factors of air toxic compounds in the year 2012 when this policy began as implemented by the Thai government were approximately 93 %, 62 %, 59 % and 59 %, a decrease as compared to the BAU case in the same year for benzene, 1,3-butadiene, acetaldehyde and formaldehyde, respectively. The introduction of gasohol as alternative fuel was found to greatly influence the emission factors of acetaldehyde and formaldehyde. Calculated results in the year 2012 indicated that acetaldehyde average emission factor increased from 123mg/km (BAU case) to 2,272 mg/km (gasohol scenario) in the same year. However, the average emission factors of benzene and 1,3 butadiene that were the result of gasohol usage were less when compared with the BAU case.

Impact of the 2008 Global Recession on air quality over the United States: Implications for surface ozone levels from changes in NOx emissions

AbstractSatellite and ground observations detected large variability in nitrogen oxides (NOx) during the 2008 economic recession, but the impact of the recession on air quality has not been quantified. This study combines observed NOx trends and a regional chemical transport model to quantify the impact of the recession on surface ozone (O3) levels over the continental United States. The impact is quantified by simulating O3 concentrations under two emission scenarios: business‐as‐usual (BAU) and recession. In the BAU case, the emission projection from the Cross‐State Air Pollution Rule is used to estimate the “would‐be” NOx emission level in 2011. In the recession case, the actual NO2 trends observed from Air Quality System ground monitors and the Ozone Monitoring Instrument on the Aura satellite are used to obtain “realistic” changes in NOx emissions. The model prediction with the recession effect agrees better with ground O3 observations over time and space than the prediction with the BAU emission. The results show that the recession caused a 1–2 ppbv decrease in surface O3 concentration over the eastern United States, a slight increase (0.5–1 ppbv) over the Rocky Mountain region, and mixed changes in the Pacific West. The gain in air quality benefits during the recession, however, could be quickly offset by the much slower emission reduction rate during the post‐recession period.

Future energy scenarios of household in Bhaktapur District

Energy plays a pervasive and critically important role in economic and social development. So, energy planning is important area of study. For Bhaktapur district energy plan, the survey was done by using the questionnaire. Total of 91 samples from rural area and 112 samples from urban area were taken to prepare primary database. The total energy demand was 952 TJ in rural area and 458 TJ in urban area in 2013.
 LEAP (Long-Range Energy Alternative Planning System) software was used for energy planning. Five scenarios, Business as Usual (BAU), Reference (REF), Accelerated Growth Rate (ACC), and Sustainable Energy for All (SE4ALL) in REF and ACC case scenarios were developed. Total energy demand in 2030 will be 2,748 TJ for BAU, 3,799 TJ for REF and 6,203 TJ for ACC case whereas total demand limits from 766 TJ and 1,241 TJ in SE4ALL scenario in REF and ACC case respectively. Again the total energy demand for 2045 will be 4,945 TJ, 9,104 TJ and 22,592 TJ for BAU, REF and ACC case respectively. Total energy demand for SE4ALL scenario will be 1,807 TJ and 4,381 TJ for REF and ACC case respectively. The GHG reduction up to 2045 by SE4ALL approach is 1.79 million metric tons of CO2 equivalent in REF and 3.54 million metric tons of CO2 equivalent in ACC Scenario.

Development and application of EEAST: A life cycle based model for use of harvested rainwater and composting toilets in buildings

Harvested rainwater systems and composting toilets are expected to be an important part of sustainable solutions in buildings. Yet, to this date, a model evaluating their economic and environmental impact has been missing. To address this need, a life cycle based model, EEAST was developed. EEAST was designed to compare the business as usual (BAU) case of using potable water for toilet flushing and irrigation to alternative scenarios of rainwater harvesting and composting toilet based technologies. In EEAST, building characteristics, occupancy, and precipitation are used to size the harvested rainwater and composting toilet systems. Then, life cycle costing and life cycle assessment methods are used to estimate cost, energy, and greenhouse gas (GHG) emission payback periods (PPs) for five alternative scenarios. The scenarios modeled include use of harvested rainwater for toilet flushing, for irrigation, or both; and use of composting toilets with or without harvested rainwater use for irrigation. A sample simulation using EEAST showed that for the office building modeled, the cost PPs were greater than energy PPs which in turn were greater than GHG emission PPs. This was primarily due to energy and emission intensive nature of the centralized water and wastewater infrastructure. The sample simulation also suggested that the composting toilets may have the best performance in all criteria. However, EEAST does not explicitly model solids management and as such may give composting toilets an unfair advantage compared to flush based toilets. EEAST results were found to be very sensitive to cost values used in the model. With the availability of EEAST, life cycle cost, energy, and GHG emissions can now be performed fairly easily by building designers and researchers. Future work is recommended to further improve EEAST and evaluate it for different types of buildings and climates so as to better understand when composting toilets and harvested rainwater systems outperform the BAU case in building design.

Scenario analysis on alternative fuel/vehicle for China’s future road transport: Life-cycle energy demand and GHG emissions

The rapid growth of vehicles has resulted in continuing growth in China’s oil demand. This paper analyzes future trends of both direct and life cycle energy demand (ED) and greenhouse gas (GHG) emissions in China’s road transport sector, and assesses the effectiveness of possible reduction measures by using alternative vehicles/fuels. A model is developed to derive a historical trend and to project future trends. The government is assumed to do nothing additional in the future to influence the long-term trends in the business as usual (BAU) scenario. Four specific scenarios are used to describe the future cases where different alternative fuel/vehicles are applied. The best case scenario is set to represent the most optimized case. Direct ED and GHG emissions would reach 734 million tonnes of oil equivalent and 2384 million tonnes carbon dioxide equivalent by 2050 in the BAU case, respectively, more than 5.6 times of 2007 levels. Compared with the BAU case, the relative reductions achieved in the best case would be 15.8% and 27.6% for life cycle ED and GHG emissions, respectively. It is suggested for future policy implementation to support sustainable biofuel and high efficient electric-vehicles, and the deployment of coal-based fuels accompanied with low-carbon technology.

The potential for greenhouse gases mitigation in household sector of Iran: cases of price reform/efficiency improvement and scenario for 2000–2010

Iran's demographic profile is sharply youth oriented and this upcoming generation's needs for employment and housing, coupled with low-energy efficiency vectors and consumption patterns, has created a constant rise in energy demand and greenhouse gas (GHGs) emissions in the residential sector. Improved energy efficiency as a national policy lynchpin for demand reduction and GHGs mitigation, has become commonplace. OPEC countries however, Iran included, suffer an obvious lack of consumer incentive because of low fuel prices. This study evaluates the twin impacts of price reform and efficiency programs on energy carriers’ consumption and GHGs mitigation in the Iranian housing sector. For this purpose, the demand functions for energy carriers, has been developed by econometrics process models.The results reveal that price elasticity for electricity demand in the Constant Elasticity Model for the short-run while the long-run is −0.142 and −0.901, respectively. In the Variable Elasticity Model the 250% increase in electricity rates in the short-run resulted in a price elasticity change from −0.02 to −0.475, hence the 250% increase in electricity pricing for the long-run resulted in the price elasticity change from −0.15 to −2.0.Finally, aided by a Scenario-Based Approach the impact of fuel pricing and efficiency improvement in trends of energy demand and GHGs emission were assessed in a Scenarios Base, developed on two different cases of Business-as-Usual (BAU) and Management. The results indicate that in the BAU case between 2000 and 2011, the energy demand and CO2 emission increases with an annual growth rate of 7.5% and 6.8%, respectively.Comparatively, if the energy carriers’ price is increased to border price and energy efficiency programs are implemented, they will stimulate carriers’ demand and CO2 emissions growth rate decreases to 4.94% and 3.1%, respectively.

Studies of breakeven prices and electricity supply potentials of nuclear fusion by a long-term world energy and environment model

In response to social demand, this paper investigates the breakeven price (BP) and potential electricity supply of nuclear fusion energy in the 21st century by means of a world energy and environment model. We set the following objectives in this paper: (i) to reveal the economics of the introduction conditions of nuclear fusion; (ii) to know when tokamak-type nuclear fusion reactors are expected to be introduced cost-effectively into future energy systems; (iii) to estimate the share in 2100 of electricity produced by the presently designed reactors that could be economically selected in the year. The model can give in detail the energy and environment technologies and price-induced energy saving, and can illustrate optimal energy supply structures by minimizing the costs of total discounted energy systems at a discount rate of 5%. The following parameters of nuclear fusion were considered: cost of electricity (COE) in the nuclear fusion introduction year, annual COE reduction rates, regional introduction year, and regional nuclear fusion capacity projection. The investigations are carried out for three nuclear fusion projections one of which includes tritium breeding constraints, four future CO2 concentration constraints, and technological assumptions on fossil fuels, nuclear fission, CO2 sequestration, and anonymous innovative technologies. It is concluded that: (1) the BPs are from 65 to 125 mill kW−1 h−1 depending on the introduction year of nuclear fusion under the 550 ppmv CO2 concentration constraints; those of a business-as-usual (BAU) case are from 51 to 68 mill kW−1h−1. Uncertainties resulting from the CO2 concentration constraints and the technological options influenced the BPs by plus/minus some 10–30 mill kW−1h−1, (2) tokamak-type nuclear fusion reactors (as presently designed, with a COE range around 70–130 mill kW−1h−1) would be favourably introduced into energy systems after 2060 based on the economic criteria under the 450 and 550 ppmv CO2 concentration constraint, but not selected under the BAU case and 650 ppmv CO2 concentration constraint, and (3) the share of electricity in 2100 produced by the presently designed tokamak-type nuclear fusion reactors (introduced after 2060) is well below 30%. It should be noted that these conclusions are based upon varieties of uncertainties in scenarios and data assumptions on nuclear fusion as well as technological options.

Addressing energy-related challenges for the US buildings sector: results from the clean energy futures study

This article presents dollar, energy, and carbon savings associated with adoption of more energy-efficient technologies in the buildings sector for two policy scenarios that represent departures from business-as-usual (BAU) case assumptions. Both scenarios result in net savings in the total cost of providing energy services relative to the BAU case (accounting for fuel expenditures and the direct incremental costs of efficiency programs and investments in the scenario), while still saving energy and reducing carbon emissions. Primary energy savings for the building sector are about 18% in the advanced scenario in 2020 relative to the BAU case. Total carbon savings in that year, including both demand and supply side effects, are almost 40% of BAU emissions. These savings reduce carbon emissions from this sector to below 1990 levels by 2020.