Regulatory potential for increasing small scale grid connected photovoltaic (PV) deployment in Australia

The last decade has seen significant innovation and change in regulatory incentives to support photovoltaic deployment globally. With high fossil fuel dependency and abundant solar resource availability in Australia, grid connected photovoltaics are a viable low carbon technology option in existing electricity grids. Drawing on international examples, the potential to increase grid PV deployment through government response and regulation is explored. For each renewable energy certificate (REC) earned by small scale photovoltaics until 2012, the market provides four additional certificates under the current banded renewable targets. Our analysis indicates that REC eligibility is not accurately estimated currently, and an energy model is developed to calculate the variance. The energy model estimates as much as 26% additional REC’s to be obtained by a 3 kWp PV system, when compared to the currently used regulatory method. Moreover, the provision of REC’s increases benefits to PV technologies, in the process distorting CO₂ abatement (0.21 tonne/REC) by 68%, when PV displaces peaking natural gas plants. Consideration of the secondary effects of a banded structure on emissions trading market is important in the context of designing a range of initiatives intended to support a transition to a low carbon electricity sector.     

Battery control for leveling the amount of electricity purchase in smart‐energy houses

An optimal operation method in smart‐energy houses with photovoltaics (PV) and a storage battery was investigated in a trial production system. In this method, the inverse current of the PV output is not conveyed to the commercial electricity system as operation conditions. Instead, the excess of the consumed PV power is applied to leveling the electricity purchase by appropriately charging and discharging the storage battery. To validate the proposed system, a lithium battery (4 kWh) and PV cell (3 kW) used in average individual houses was installed in a smart‐energy house in a local city (Kitami) in Japan. Another example was introduced into a wider area (Hokkaido, Japan). Accounting for the error between the weather forecast and actual solar radiation, the trial production system reduced the range in the electricity purchase amount by 75.0%, 77.0%, and 73.0% on a representative day in January, April, and July, respectively. The accuracy of the reduction effect in the trial production system, obtained in the proposed optimization analysis, ranged from 1.9% to 7.2%. Moreover, the CO₂ emissions were reduced by 1.990 kg‐CO₂/(Day‐House) in January, 2.910 kg‐CO₂/(Day‐House) in April, and 2.210 kg‐CO₂/(Day‐House) in July.     

Valuation of marginal CO2 abatement options for electric power plants in Korea

The electricity generation sector in Korea is under pressure to mitigate greenhouse gases as directed by the Kyoto Protocol. The principal compliance options for power companies under the cap-and-trade include the application of direct CO₂ emission abatement and the procurement of emission allowances. The objective of this paper is to provide an analytical framework for assessing the cost-effectiveness of these options. We attempt to derive the marginal abatement cost for CO₂ using the output distance function and analyze the relative advantages of emission allowance procurement option as compared to direct abatement option. Real-option approach is adopted to incorporate emission allowance price uncertainty. Empirical result shows the marginal abatement cost with an average of €14.04/ton CO₂ for fossil-fueled power plants and confirms the existence of substantial cost heterogeneity among plants which is sufficient to achieve trading gains in allowance market. The comparison of two options enables us to identify the optimal position of the compliance for each plant. Sensitivity analyses are also presented with regard to several key parameters including the initial allowance prices and interest rate. The result of this paper may help Korean power plants to prepare for upcoming regulations targeted toward the reduction of domestic greenhouse gases.     

Optimal sizing of grid-connected photovoltaic energy system in Saudi Arabia

Resource optimization is a major factor in the assessment of the effectiveness of renewable energy systems. Various methods have been utilized by different researchers in planning and sizing the grid-connected PV systems. This paper analyzes the optimal photovoltaic (PV) array and inverter sizes for a grid-connected PV system. Unmet load, excess electricity, fraction of renewable electricity, net present cost (NPC) and carbon dioxide (CO₂) emissions percentage are considered in order to obtain optimal sizing of the grid-connected PV system. An optimum result, with unmet load and excess electricity of 0%, for serving electricity in Makkah, Saudi Arabia is achieved with the PV inverter size ratio of R = 1 with minimized CO₂ emissions. However, inverter size can be downsized to 68% of the PV nominal power to reduce the inverter cost, and hence decrease the total NPC of the system.     

Considerations for the calculation of greenhouse gas reduction by photovoltaic solar energy

A CO₂ comprehensive balance within the life-cycle of a photovoltaic energy system requires careful examination of the CO₂ sinks and sources at the locations and under the conditions of production of each component, during transport, installation and operation, as well as at the site of recycling. Calculations of the possible effect on CO₂ reduction by PV energy systems may be incorrect if system borders are not set wide enough and remain on a national level, as can be found in the literature. For the examples of Brazil and Germany, the effective CO₂ reductions have been derived, also considering possible interchange scenarios for production and operation of the PV systems considering the carbon dioxide intensity of the local electricity grids. In the case of Brazil also off-grid applications and the substitution of diesel generating sets by photovoltaics are examined: CO₂ reduction may reach 26,805 kg/kW_p in that case. Doing these calculations, the compositions of the local grids and their CO₂ intensity at the time of PV grid injection have to be taken into account. Also possible changes of the generation fuel mix in the future have to be considered: During the operation time of a PV system, different kinds of power plants could be installed that might change the CO₂ intensity of the grid. In the future also advanced technologies such as thin films have to be considered.     

Forward-looking assessment of the GHG abatement cost: Application to China

Evaluation of abatement costs is critical in setting reduction goals and devising climate policy. However, reliable forward-looking assessment of the short-term effects of climate policy remains a major challenge. Using panel data of 30 Chinese provinces during 1997–2015, we first estimate the marginal CO₂ abatement costs using a novel data-driven approach, convex quantile regression. Based on the marginal abatement cost estimates and China's plans regarding carbon intensity reduction and economic growth, we present a forward-looking assessment of the abatement costs for Chinese provinces for 2016–2020. Our main finding is that all the Chinese provinces have a negative abatement cost, which means these provinces can benefit from an increase in the absolute level of CO₂ emissions despite the constraint on carbon intensity. The magnitudes of economic benefits exhibit a significant regional disparity because some provinces can increase more CO₂ emissions than others. However, there is still costly carbon intensity abatement relative to a counterfactual where the provinces meet their economic growth targets but in the absence of the intensity reduction constraints. Policy implications have been proposed to enhance the efficiency and fairness of climate policy in China.     

BIPV for the high-temperature, high-rise, high-density cities of S. China: The related projects of PV HKU research group to facilitate BIPV application

In cities where high-rise commercial developments have overtaken industry as the peak electricity consumer, sophisticated building integrated photovoltaics (BIPV) can offset the demand by generating electricity during daytime peak consumption. The PV HKU Research Group's related projects, in a triple strategy of Technology Assessment, Technology Application & Regulatory Framework, aims to provide the government and community with the information, experience and appropriate legislation to facilitate widespread BIPV applications, and assist compliance with the Kyoto Protocol on CO₂ emissions reduction.     

Marginal CO2 abatement costs: Findings from alternative shadow price estimates for Shanghai industrial sectors

Shanghai, one of the most developed cities in China, is implementing a pilot regional carbon emission trading scheme. Estimating the marginal abatement costs of CO₂ emissions for the industrial sectors covered in Shanghai's emission trading scheme provides the government and participating firms useful information for devising compliance policies. This paper employs multiple distance function approaches to estimating the shadow prices of CO₂ emissions for Shanghai industrial sectors. Our empirical results show that the overall weighted average of shadow price estimates by different approaches ranges between 394.5 and 1906.1 Yuan/ton, which indicates that model choice truly has a significant effect on the shadow price estimation. We have also identified a negative relationship between the shadow price of CO₂ emissions and carbon intensity, and the heavy industries with higher carbon intensities tend to have lower shadow prices. It has been suggested that Shanghai municipal government take various measures to improve its carbon market, e.g. using the marginal abatement costs of participating sectors/firms as a criterion in the initial allocation of carbon emission allowances.     

Robust MACCs? The topography of abatement by fuel switching in the European power sector

This paper employs a simulation model of the European power sector to analyze the abatement response to a CO₂ price through fuel switching, one of principal means of reducing greenhouse gas emissions in any economy. Abatement is shown to depend not only on the price of allowances, but also and more importantly on the load level of the system and the ratio between natural gas and coal prices. The interplay of these different determinants vitiates any simple relation between a CO₂ price and abatement and requires the development of more than two-dimensional graphics to illustrate these complex relationships. In the terms of the literature on the use of marginal abatement cost curves (MACCs), we find that these MACCs are not robust as usually defined and we suggest that the more complex topography developed in this paper may be more helpful in visualizing this abatement response to a CO₂ price.     

Quantifying CO2 abatement costs in the power sector

CO₂ cap-and-trade mechanisms and CO₂ emission taxes are becoming increasingly widespread. To assess the impact of a CO₂ price, marginal abatement cost curves (MACCs) are a commonly used tool by policy makers, providing a direct graphical link between a CO₂ price and the expected abatement. However, such MACCs can suffer from issues related to robustness and granularity. This paper focuses on the relation between a CO₂ emission cost and CO₂ emission reductions in the power sector. The authors present a new methodology that improves the understanding of the relation between a CO₂ cost and CO₂ abatement. The methodology is based on the insight that CO₂ emissions in the power sector are driven by the composition of the conventional power portfolio, the residual load and the generation costs of the conventional units. The methodology addresses both the robustness issue and the granularity issue related to MACCs. The methodology is based on a bottom-up approach, starting from engineering knowledge of the power sector. It offers policy makers a new tool to assess CO₂ abatement options. The methodology is applied to the Central Western European power system and illustrates possible interaction effects between, e.g., fuel switching and renewables deployment.     

Lower electricity prices and greenhouse gas emissions due to rooftop solar: empirical results for Massachusetts

Monthly and hourly correlations among photovoltaic (PV) capacity utilization, electricity prices, electricity consumption, and the thermal efficiency of power plants in Massachusetts reduce electricity prices and carbon emissions beyond average calculations. PV utilization rates are highest when the thermal efficiencies of natural gas fired power plants are lowest, which reduces emissions of CO₂ and CH₄ by 0.3% relative to the annual average emission rate. There is a positive correlation between PV utilization rates and electricity prices, which raises the implied price of PV electricity by up to 10% relative to the annual average price, such that the average MWh reduces electricity prices by $0.26–$1.86 per MWh. These price reductions save Massachusetts rate-payers $184 million between 2010 and 2012. The current and net present values of these savings are greater than the cost of solar renewable energy credits which is the policy instrument that is used to accelerate the installation of PV capacity. Together, these results suggest that rooftop PV is an economically viable source of power in Massachusetts even though it has not reached socket parity.     

Estimation of the marginal abatement costs of airborne pollutants in Korea’s power generation sector

Using an output distance function and its duality to the revenue function, we estimated the marginal abatement costs of airborne pollutants of bunker-C and coal fired power plants in Korea. The average marginal abatement costs are 310.6 thousand won per ton for SO_x, 146.7 thousand won per ton for NO_x, 15 482.3 thousand won per ton for TSP, and 3.8 thousand won per ton for CO₂ for the period of 1990–1995. These estimates are well within the range of the results by the previous studies in the US. The wide variations in the marginal abatement costs by the types of plant imply that Korea’s regulatory policy on pollution has not achieved the cost-efficiency in reducing emissions.     

Potential of renewable surplus electricity for power-to-gas and geo-methanation in Switzerland

Energy systems are increasingly exposed to variable surplus electricity from renewable sources, particularly photovoltaics. This study estimates the potential to use surplus electricity for power-to-gas with geo-methanation for Switzerland by integrated energy system and power-to-gas modelling. Various CO₂ point sources are assessed concerning exploitable emissions for power-to-gas, which were found to be abundantly available such that 60 TWh surplus electricity could be converted to methane, which is the equivalent of the current annual Swiss natural gas demand. However, the maximum available surplus electricity is only 19 TWh even in a scenario with high photovoltaic expansion. Moreover, making this surplus electricity available for power-to-gas requires an ideal load shifting capacity of up to 10 times the currently installed pumped-hydro capacity. Considering also geological and economic boundary conditions for geo-methanation at run-of-river and municipal waste incinerator sites with nearby CO₂ sources reduces the exploitable surplus electricity from 19 to 2 TWh.     

Unintended consequences of cap-and-trade? Evidence from the Regional Greenhouse Gas Initiative

Cap-and-trade programs are designed to minimize the overall cost of pollution control by effectively allowing firms with low abatement costs to reduce emissions on behalf of those with higher abatement costs. However, these trades redistribute where emissions are generated, which has important implications for welfare because many pollutants have differential environmental and health impacts depending on where they are emitted. This paper compiles and analyzes a national data set of power plant emissions in order to assess how the Regional Greenhouse Gas Initiative (RGGI), a carbon dioxide (CO₂) cap-and-trade program involving nine states in the United States, impacts the emissions and damages from copollutants. Our results suggest that, in addition to achieving its goal of reducing CO₂, the program has lowered the quantity of sulfur dioxide (SO₂) emissions as well as associated damages in the policy region. However, two factors diminish the overall benefits from the program. First, within the RGGI region, trading shifts electricity generation to locations with higher marginal damages for SO₂. Second, there is leakage of electricity generation and emissions to nearby states, although this latter effect is more modest than ex ante analyses predicted.     

The environmental impacts of green technologies in TX

Using detailed electricity consumption and solar generation data from homes in an Austin TX neighborhood between 2013 and 2015, we calculate the environmental benefits of electric vehicles and rooftop solar panels. We estimate time-varying electric grid marginal emissions and water consumption rates in ERCOT through a regression based analysis, and find that emissions and water consumption rates are lowest at high demand times due to those hours' reliance on cleaner natural gas generators. We utilize these emissions and water consumption rates to estimate the avoided GHGs and water consumption from grid electricity that solar panels provide. For electric vehicles, we estimate the net effect of this technology, given the avoided gasoline consumption but increase in grid-related charging. We find that, on average, solar panels avoid approximately 75% of yearly grid-related emissions (0.7 tons CO₂/year per kW of solar capacity) and yearly grid-related water consumption (400 gal/year per kW of solar capacity), where the benefits depend on the orientation of the panels. We also find that electric vehicle deployment results in avoiding up to 70% of fuel-related emissions (3.5 tons CO₂/year) and 60% of fuel-related water consumption (1400 gal/year), though the benefits significantly decrease with the efficiency of the counterfactual vehicle.     

Directed technical change and the adoption of CO2 abatement technology: The case of CO2 capture and storage

This paper studies the cost-effectiveness of combining traditional environmental policy, such as CO₂-trading schemes, and technology policy that has aims of reducing the cost and speeding the adoption of CO₂ abatement technology. For this purpose, we develop a dynamic general equilibrium model that captures empirical links between CO₂ emissions associated with energy use, directed technical change and the economy. We specify CO₂ capture and storage (CCS) as a discrete CO₂ abatement technology. We find that combining CO₂-trading schemes with an adoption subsidy is the most effective instrument to induce adoption of the CCS technology. Such a subsidy directly improves the competitiveness of the CCS technology by compensating for its markup over the cost of conventional electricity. Yet, introducing R&D subsidies throughout the entire economy leads to faster adoption of the CCS technology as well and in addition can be cost-effective in achieving the abatement target.     

CO2 savings of ground source heat pump systems – A regional analysis

In the current study the savings of CO₂ emissions due to the use of ground source heat pump (GSHP) systems was investigated in comparison to conventional heating systems. Based on a subsidy program for GSHP systems in southwest Germany, the regional, average, and total CO₂ savings of 1105 installed GSHP systems were determined on a regional scale. The emitted CO₂ per kWh of heating demand for the studied scenario resulted in 149 g CO₂/kWh for GSHP using the German electricity mix and 65 g CO₂/kWh using the regional electricity mix, which results in CO₂ savings of 35% or 72%, respectively. Similar CO₂ avoidances of GSHP systems were found in American and European studies ranging between 15% and 77% strongly depending on the supplied energy for the heat pumps and the efficiency of installation. The resulting CO₂ savings for one installed GSHP unit in the present study therefore range between 1800 and 4000 kg per year. Nevertheless, the minimum average total annual CO₂ savings of all installed GSHP systems due to the subsidy program amounted to 2000 tons per year. The maximum regional avoided additional CO₂ emissions are primarily associated with the affluent suburbs of the most densely populated area in the region. In 2006 the total contribution of CO₂ savings due to GSHP systems in Germany was only about 3.4% of the total renewable energies. However, continuously rising numbers of installed GSHP units and the increasing use of renewable electricity demonstrate that there is a fine opportunity to substantially avoid additional CO₂ emissions associated with the provision of heating (and cooling) of buildings and other facilities.     

Life cycle sustainability assessment of electricity options for the UK

The UK electricity mix will change significantly in the future. This provides an opportunity to consider the full life cycle sustainability of the options currently considered as most suitable for the UK: gas, nuclear, offshore wind and photovoltaics (PV). In an attempt to identify the most sustainable options and inform policy, this paper applies a sustainability assessment framework developed previously by the authors to compare these electricity options. To put discussion in context, coal is also considered as a significant contributor to the current electricity supply. Each option is assessed and compared in terms of its economic, environmental and social implications, using a range of sustainability indicators. The results show that no one technology is superior and that certain trade‐offs must be made. For example, nuclear and offshore wind power have the lowest life cycle environmental impacts, except for freshwater ecotoxicity for which gas is the best option; coal and gas are the cheapest options (£74 and 66/MWh, respectively, at 10% discount), but both have high global warming potential (1072 and 379 g CO₂ eq./kWh); PV has relatively low global warming potential (88 g CO₂ eq./kWh) but high cost (£302/MWh), as well as high ozone layer and resource depletion. Nuclear, wind and PV increase some aspects of energy security: in the case of nuclear, this is due to inherent fuel storage capabilities (energy density 290 million times that of natural gas), whereas wind and PV decrease fossil fuel import requirements by up to 0.2 toe/MWh. However, all three options require additional installed capacity for grid management. Nuclear also poses complex risk and intergenerational questions such as the creation of 10.16 m³/TWh of nuclear waste for long‐term geological storage. Copyright © 2012 John Wiley & Sons, Ltd.     

Modeling the life cycle energy and environmental performance of amorphous silicon BIPV roofing in the US

Building integrated photovoltaics (BIPV) perform traditional architectural functions of walls and roofs while also generating electricity. The displacement of utility generated electricity and conventional building materials can conserve fossil fuels and have environmental benefits. A life cycle inventory model is presented that characterizes the energy and environmental performance of BIPV systems relative to the conventional grid and displaced building materials. The model is applied to an amorphous silicon PV roofing shingle in different regions across the US. The electricity production efficiency (electricity output/total primary energy input excluding insolation) for a reference BIPV system (2kW_p PV shingle system with a 6% conversion efficiency and 20 year life) ranged from 3.6 in Portland OR to 5.9 in Phoenix, AZ indicating a significant return on energy investment. The reference system had the greatest air pollution prevention benefits in cities with conventional electricity generation mixes dominated by coal and natural gas, not necessarily in cities where the insolation and displaced conventional electricity were greatest.     

GIS-based approach for potential analysis of solar PV generation at the regional scale: A case study of Fujian Province

Spatial variation of solar energy is crucial for the estimation of the regional potential and selection of construction location. This paper presents a case study of using high resolution grid map of solar radiation combined with the other restriction factors to evaluate the comprehensive potential analysis of solar PV generation at the regional scale, in order to present a framework of decision support tool for solar energy management in a regional area. The cost of PV generation is calculated based on the geographical distribution of technical potential. Moreover, geospatial supply curve (GSC) is employed to portray the evolution of available potential of photovoltaics (PV) generation with the increase of the generation cost. By integrating the economic evaluation variables of net present value and simple payback period, grid-based economic feasibility of PV generation project is then carried out under two feed-in-tariff scenarios. Finally, total CO₂ reduction potential and its spatial distribution in the study area are calculated. The results confirm that PV technology provides high potential for roof-top application and large-scale PV stations. Additionally, determining a reasonable feed-in tariff is essential for expanding the application of solar PV energy. The findings improve understanding of regional renewable energy strategies and the supply/demand assessment.