Renewable and Sustainable Energy Transition最新文献

Battery-electric vehicles provide a pathway to decarbonize heavy-duty trucking, but the market for heavy-duty battery-electric semi-trailer trucks is nascent, and specific charging requirements remain uncertain. We leverage large-scale vehicle telematics data (>205 million miles of driving) to estimate the charging behaviors and infrastructure requirements for U.S. battery-electric semi-trailer trucks within three operating segments: local, regional, and long-haul. We model two types of charging—mid-shift (fast) and off-shift (slow)—and show that off-shift charging at speeds compatible with current light-duty charging infrastructure (i.e., ≤350 kW) can supply 35 to 77% of total energy demand for local and regional trucks with ≥300-mile range. Megawatt-level speeds are required for mid-shift charging, which make up 44 to 57% of energy demand for long-haul trucks with ≥500-mile range. However, demand shifts from mid-shift to off-shift charging as the range for battery-electric trucks increases and when off-shift charging is widely available. Finally, we observe geographic trends in charging demand, finding that local trucks have greater demand within urban areas, whereas long-haul trucks have more demand along rural interstate corridors. As the range for battery-electric trucks increases, we show that charging demand shifts from rural to urban locations due to observed vehicle dwell tendencies.

In line with the Dutch Climate Agreement, multiple energy transition scenarios have been constructed for 2030 and 2050. To various extents, they project a shift towards decentralized and intermittent renewable electricity generation (wind and solar) and widespread deployment of electric vehicles and heat pumps. These developments impose challenges regarding electricity supply-demand mismatch and grid congestion. In order to gain an understanding of when and where such problems are likely to occur, temporally and spatially resolved interpretations of the energy transition scenarios are required. This paper focuses on Dutch wind energy supply and shows construction of geodatabases of scenario-specific, hourly onshore and offshore wind electricity generation profiles on an individual turbine level. For the geographical distribution of turbine capacity, datasets on historically operational turbines, planned wind parks and suggested future turbine distributions are utilized. Turbine electricity generation profiles are constructed using a high resolution 3D meteorological dataset and power curves of commercially available turbine models. They are corrected for air pressure deviations and a multitude of loss factors, including wake effects. Compared to the present-day situation, yearly country-level electricity generation is projected to be a factor 16.6, 24.6 or 12.8 higher in 2050 when following the Regional, National or International Steering scenarios, respectively. In comparison to both the present-day and 2030 situation, onshore electricity generation is projected to be more evenly spread over different parts of the country in 2050. All offshore wind exploration areas considered in this research are projected to be completely utilized by 2050.

The global transport sector is the second largest energy consumer and strongly relies on fossil fuels. Efforts for reducing GHG emissions on this sector depend on energy efficiency improvement and the use of renewable fuels and electrification. All these technologies are commercially available and each one faces some barriers to overcame environmental and financial issues. Complete vehicle electrification is still expensive, and its use as an environmentally sound solution relies on decarbonization of the electricity supply. Vehicles equipped with internal combustion engines running on renewable liquid fuels are less expensive than battery electric vehicles but its energy intensity by land area (MJ/ha) is low. We have examined an alternative where both solutions are combined through the deployment of Plug -in Hybrid Vehicles, using renewable fuel and renewable electricity. Selecting sugar cane as a source of ethanol, we can take advantage of its coproduct – electricity, used for battery charging. We have determined the well to wheel lifecycle carbon balance of PHEV consuming sugarcane-based electricity and ethanol for several scenarios being the lowest one 67gCO2e/mile. We have demonstrated that this technology is a viable alternative for climate mitigation goals. Based on published forecasts for efficiency improvements, on existing vehicle and fuel production pathways, we have shown that a car fleet of one billion units in operation by 2030 can be fueled through harvesting 125.2 million hectares of land with sugar cane and eucalyptus. Considering that ethanol and gasoline have the same performance, on miles per gallon based on their respective energy content, the total harvested area decreases to 103.7 Mha.

CO₂-Plume Geothermal (CPG) technologies are geothermal power systems that use geologically stored CO₂ as the subsurface heat extraction fluid to generate renewable energy. CPG technologies can support variable wind and solar energy technologies by providing dispatchable power, while Flexible CPG (CPG-F) facilities can provide dispatchable power, energy storage, or both simultaneously. We present the first study investigating how CPG power plants and CPG-F facilities may operate as part of a renewable-heavy electricity system by integrating plant-level power plant models with systems-level optimization models. We use North Dakota, USA as a case study to demonstrate the potential of CPG to expand the geothermal resource base to locations not typically considered for geothermal power. We find that optimal system capacity for a solar-wind-CPG model can be up to 20 times greater than peak-demand. CPG-F facilities can reduce this modeled system capacity to just over 2 times peak demand by providing energy storage over both seasonal and short-term timescales. The operational flexibility of CPG-F facilities is further leveraged to bypass the ambient air temperature constraint of CPG power plants by storing energy at critical temperatures. Across all scenarios, a tax on CO₂ emissions, on the order of hundreds of dollars per tonne, is required to financially justify using renewable energy over natural-gas power plants. Our findings suggest that CPG and CPG-F technologies may play a valuable role in future renewable-heavy electricity systems, and we propose a few recommendations to further study its integration potential.

A transition of the Bolivian power sector towards a renewable energy dominated system has been inhibited by a series of laws and policies including heavy subsidies for power generation using domestic natural gas. Within this context, alternative techno-economic scenarios are designed based on key characteristics of the system, and a series of six policy levers are used to analyze impacts on the development of the power sector. The energy-system optimization modeling framework OSeMOSYS is utilized to analyze power sector transition pathways. Techno-economic characteristics and policies are combined to develop bracketing scenarios for the future energy system, contrasting business-as-usual with an ambitious renewable energy policy scenario.

Results from the analyzed scenarios show that achieving significant reductions of GHG emissions in the Bolivian electric system will heavily depend on:1) reducing the artificial competitiveness of thermal power plants through subsidies, but also a price on carbon emissions; 2) banning high impact power plants (mainly very large hydropower plants); and 3) defining clear long-term objectives for the participation of renewables in the system, starting with objectives in current short-term plans. By examining several scenarios, relative system costs as a function of emissions reductions are determined as well. For high penetration of variable renewable energy, addition of storage will eventually be needed as dispatchable renewable resources are limited.

Since the UK’s Net Zero greenhouse gas emissions target was set in 2019, organisations across the energy systems community have released pathways on how we might get there – which end-use technologies are deployed across each sector of demand, how our fossil fuel-based energy supply would be transferred to low carbon vectors and to what extent society must change the way it demands energy services. This paper presents a comparative analysis between seven published Net Zero pathways for the UK energy system, collected from Energy Systems Catapult, National Grid ESO, Centre for Alternative Technology and the Climate Change Committee. The key findings reported are that (i) pathways that rely on less stringent behavioural changes require more ambitious technology development (and vice versa); (ii) electricity generation will increase by 51–160% to facilitate large-scale fuel-switching in heating and transport, the vast majority of which is likely to be generated from variable renewable sources; (iii) hydrogen is an important energy vector in meeting Net Zero for all pathways, providing 100–591 TWh annually by 2050, though the growth in demand is heavily dependent on the extent to which it is used in supplying heating and transport demand. This paper also presents a re-visited analysis of the potential renewable electricity generation resource in the UK. It was found that the resource for renewable electricity generation outstrips the UK’s projected 2050 electricity demand by a factor 12–20 depending on the pathway. As made clear in all seven pathways, large-scale deployment of flexibility and storage is required to match this abundant resource to our energy demand.

DC fast-charging stations can charge an electric vehicle several times faster than Level 2 AC charging stations. Using a network of DC charging stations, it becomes possible to travel in electric vehicles for long-distance, cross-country driving with only short recharging stops. This paper examines and compares typical customer usage patterns at DC fast-charging stations (50 kW) against Level 2 AC charging stations (7 kW) to study the benefits of transitioning to DC charging for Western Australia. It includes data collected from The University of Western Australia’s AC and DC charging network in the Perth metropolitan area and stations along the highway connecting Perth to Augusta in the rural South West of Western Australia (over 300 km apart). A cost model is drawn up to calculate the local operating cost and break-even requirement across several different styles of charging stations. User behaviour and the adoption of certain charging infrastructures are crucial for the general uptake of electric vehicles. Notwithstanding, national electric vehicle charging standards and infrastructure availability have a fundamental influence on the electrification of transport.

Blending hydrogen (H₂) produced from PEM electrolysis coupled to Renewable Energy Sources (RES) in the existing Natural Gas (NG) network is a promising option for the deep decarbonization of the gas sector. However, blending H₂ with NG significantly affects the thermophysical properties of the gas mixture, changing the gas supply requirements to meet the demand. In this work, different scenarios of green hydrogen blending (Blend Ratio BR equal to 5/10/15/20%_vol) are analyzed at the national level with different temporal constraints (hour/day/week/month/year) based on real gas demand data in Italy, addressing both design requirements (RES and PEM electrolyzer capacity) via Linear Programming (LP) and carrying out dynamic simulations of different operational strategies (constant or variable blend). Although H₂/NG blending provides a huge opportunity in terms of deployed H₂ volume, higher BRs show rapidly increasing design requirements (1.3-1.5 GW_e/%_vol and 2.5-3 GW_e/%_vol for PEM electrolyzers and RES capacity, respectively) and a significative increase of the total gas mixture volume (0.83%/%_vol) which hinders the CO₂ reduction potential (0.37%/%_vol). A variable blend operation strategy (allowing a variation of BR within the analyzed period) allows to balance a variable H₂ production from RES. Wider temporal constraints imply several beneficial effects such as relaxing design constraints and avoiding the implementation of an external storage. The Levelized Cost Of Hydrogen (LCOH) is preliminarily estimated at around 7.3 $/kg for yearly scenarios (best-case), although shorter temporal constraints entail significant excess hydrogen which would increase the LCOH if not deployed for other applications.

Within techno-economic models for climate and energy scenarios, labour is assumed to be available just-in-time – even as cost-optimisation electricity system modelling typically generates development profiles with sharp peaks and troughs which would make labour supply and management very challenging. Local job creation is often framed as a key benefit for regional communities and important for building social licence in host regions to enable rapid, large-scale renewable energy development. Yet, whilst there is a large body of studies projecting employment volumes under climate and energy transition scenarios, there has been limited empirical research on the challenges, opportunities and solutions for labour supply and workforce development within local and regional labour markets.

Through a study of five renewable energy zones being established within an electricity system dominated by coal generation in New South Wales (Australia), our study contributes to the understanding of the employment constraints that could emerge and need to be addressed for a ‘fair and fast’ energy transition. As the global transition to renewable energy accelerates, local workforce development will become more important as competition for labour intensifies. However, significant barriers to building a regional workforce for renewable energy are identified including ‘boom-bust’ development cycles, the depth of regional labour markets in key occupations, competition for labour across inter-connected sectors, the concentration of socially disadvantaged communities in under-employed populations and demographic changes, especially population ageing.

Based on the case study, four key policy implications are identified for other jurisdictions. Firstly, ‘smoothing’ the development profile to avoid boom-bust cycles can be implemented consistent with renewable energy targets aligned with the Paris Climate agreement. Secondly, there needs to be a coordinated approach between government, industry and training providers to build training capacity – market-led approaches are unlikely to work for renewable energy in regional areas. Thirdly, training and employment pathways need to be built for diverse labour market segments to develop a regional workforce, including disadvantaged groups outside the workforce. Fourthly, renewable energy should be managed as part of an ‘ecosystem’ to develop a workforce that can move between renewable energy and adjacent sectors such as resources, infrastructure and manufacturing.