Increasing RES penetration through H2 technologies on Flores island,Azores: A techno-economic analysis

On Flores island (Azores, Portugal), energy production depends up to 47% on fossil fuels, namely Diesel. To minimize CO₂ emissions, the dependency on fuel prices, and to mitigate the consequences of variability and intermittency of renewable energy sources, a new energy system, based on H₂ storage was analysed. To achieve the optimal size of the system, a computer model was developed and a multi-objective genetic algorithm function was used to minimize three objectives: the difference of levelised cost of energy (△LCOE), CO₂ emissions and the percentage of renewable energy dumped (R_{RES, dump}). From the set of solutions obtained, one that meets R_{RES, dump} ≤ 1%, lowest CO₂ emissions and lowest △LCOE is chosen and an economical and energetic analysis is performed. The newly proposed system reduces Diesel consumption by 68,7% (1057487 L/year) and CO₂ emissions by 65,9% (2455,1 CO₂ tons/year) achieving a renewable energy sources (RES) penetration of 89% (36% increase), but fails to decrease the levelised cost of energy (56,62 €/MWh increase). However, a way to make the project viable through financial support is presented and an alternative to reduce the levelised cost of energy by commercialising the products of electrolysis, hydrogen and oxygen, is proposed. Finally, it is expected that with further research and development of H₂ technologies, economic and energetic results will get more advantageous, opening up new perspectives for the future.     

An evaluation of biomass co-firing in Europe

Reduction of the emissions of greenhouses gases, increasing the share of renewable energy sources (RES) in the energy balance, increasing electricity production from renewable energy sources and decreasing energy dependency represent the main goals of all current strategies in Europe. Biomass co-firing in large coal-based thermal power plants provides a considerable opportunity to increase the share of RES in the primary energy balance and the share of electricity from RES in gross electricity consumption in a country. Biomass-coal co-firing means reducing CO₂ and SO₂, emissions and it may also reduce NO_x emissions, and also represents a near-term, low-risk, low-cost and sustainable energy development. Biomass-coal co-firing is the most effective measure to reduce CO₂ emissions, because it substitutes coal, which has the most intensive CO₂ emissions per kWh electricity production, by biomass, with a zero net emission of CO₂. Biomass co-firing experience worldwide are reviewed in this paper. Biomass co-firing has been successfully demonstrated in over 150 installations worldwide for most combinations of fuels and boiler types in the range of 50–700 MWe, although a number of very small plants have also been involved. More than a hundred of these have been in Europe. A key indicator for the assessment of biomass co-firing is intrduced and used to evaluate all available biomass co-firing technologies.     

On the optimal selection of wall cladding system to reduce direct and indirect CO2 emissions

Buildings have direct and indirect impacts on the CO₂ emissions. This paper presents a study on the impact of wall systems and cladding materials on the CO₂ emissions and aims to analyse the performance of those systems in order to provide designers with reliable technical data. The studied systems include stucco, masonry veneer, aluminium siding, vinyl siding and the exterior insulation and finish systems (EIFS). To evaluate the economic performance, environmental performance and embodied energy, green building modelling system was used, while to estimate the impact of operational energy, a simulation model was first used and then simple bottom-up model constructed. A sensitivity analysis was conducted in order to determine the relative influence of each system on a representative educational building. It was found that some cladding materials reduce the direct CO₂ emissions, but provide a moderate reduction in terms of operational energy, and vice versa. Others positively impact the embodied energy and environmental performance and can optimise the operational energy performance. Therefore, a careful evaluation should be carried out in selecting wall cladding systems and finishing materials in order to reduce the CO₂ emissions effectively.     

Identifying the driving forces of national and regional CO2 emissions in China: Based on temporal and spatial decomposition analysis models

This study explores the driving forces of the changes of national and regional CO₂ emissions using temporal decomposition analysis model, and investigates the driving forces of the differences of CO₂ emissions between China's 30 regions and the national average using spatial decomposition analysis model. The changes or the differences in national and regional CO₂ emissions during 2000–2014 are decomposed into nine underlying determinants. Temporal decomposition results show that economic scale effect is the dominant driving force leading to the increases in both national and regional CO₂ emissions, while energy intensity effect is the main contributor to the reduction of CO₂ emissions. Contribution of various variables to CO₂ emissions between eastern region and central region are roughly same. Spatial decomposition results demonstrate that the differences of CO₂ emissions among China's 30 regions are expanding increasingly. Economic scale effect is main driving force responsible for the difference in CO₂ emissions among regions, and energy intensity effect, energy structure effect and industrial structure effect are also important factors which result in the increasing differences in regional CO₂ emissions. In addition, resource-based and less developed regions have greater potential in the reduction of CO₂ emissions. Understanding CO₂ emissions and the driving forces of various regions is critical for developing regional mitigation strategies in China.     

Reduction of air pollutant emissions using renewable energy sources for power generation in Cyprus

In this paper, the options of using Renewable Energy Sources (RES) in the power system of Cyprus are examined in order to reduce air pollutant emissions. Power generation is the major contributor to total emissions in Cyprus with a share of 36% in carbon dioxide (CO₂), 62% in sulfur dioxide (SO₂), 20% in nitrogen oxides (NO_x) and 55% in nitrous oxide (N₂O) emission according to the emission inventory for the year 2002. The emissions reduction potential in the energy system of Cyprus is notable since the use of RES for power generation has so far been negligible. The national action plan for the promotion of electricity production from RES for the years 2009–2013 includes large-scale projects of total capacity target 211 MW_el, and in case is accomplished, there will be significant production of electricity, which is estimated to 11.2% of 2008 gross production. The resulting reduction of air pollutant emissions corresponds to 453 kt/yr of CO₂, 4.69 kt/yr of SO₂, 1.21 kt/yr of NO_x, 0.26 kt/yr of N₂O emissions and exceeds the emissions of Moni power station, the oldest in Cyprus and the one with the lower efficiency. Emissions reduction potential is even larger, since additional measures for rational use of electricity together with RES applications in final consumption sectors could contribute to decrease the demanded amount of electricity.     

Long-term CO2 emissions reduction target and scenarios of power sector in Taiwan

This study analyses a series of carbon dioxide (CO₂) emissions abatement scenarios of the power sector in Taiwan according to the Sustainable Energy Policy Guidelines, which was released by Executive Yuan in June 2008. The MARKAL-MACRO energy model was adopted to evaluate economic impacts and optimal energy deployment for CO₂ emissions reduction scenarios. This study includes analyses of life extension of nuclear power plant, the construction of new nuclear power units, commercialized timing of fossil fuel power plants with CO₂ capture and storage (CCS) technology and two alternative flexible trajectories of CO₂ emissions constraints. The CO₂ emissions reduction target in reference reduction scenario is back to 70% of 2000 levels in 2050. The two alternative flexible scenarios, Rt4 and Rt5, are back to 70% of 2005 and 80% of 2005 levels in 2050. The results show that nuclear power plants and CCS technology will further lower the marginal cost of CO₂ emissions reduction. Gross domestic product (GDP) loss rate in reference reduction scenario is 16.9% in 2050, but 8.9% and 6.4% in Rt4 and Rt5, respectively. This study shows the economic impacts in achieving Taiwan's CO₂ emissions mitigation targets and reveals feasible CO₂ emissions reduction strategies for the power sector.     

Systemic approach for techno-economic evaluation of triple hybrid (RO,MSF and power generation) scheme including accounting of CO2 emission

A system of models for the techno-economic evaluation of a triple hybrid, reverse osmosis (RO), multistage flush (MSF) and power generation process has been developed. There are three groups of models underlying the system: (A) models describing power-generating technology; (B) models describing RO desalination, and (C) models describing MSF desalination. Any group of individual models, in turn, consists of a set of submodels of different hierarchy levels; they are: (1) technological submodel, (2) fuel or energy submodel, (3) ecological submodel and (4) economic submodel. (1) The technological submodel is focused on the calculation of technological characteristics at different operating loads of the generating systems; (2) the fuel or energy submodel covers the calculation of fuel influx into power-generating systems at different operating loads; (3) the ecological submodel focuses on estimation of CO₂ emissions at different operating regimes; (4) the economic submodel gives values of economic indicators, such as (a) cost of water, (b) cost of energy, and (c) accounting for CO₂ emissions through imposed carbon tax (assuming rates of environmental taxes recommended by European Union tax legislation). This paper contains an analysis of the behavior of economic and ecological indicators for various technological parameters and economic assumptions, such as (1) load, specific fuel consumption and efficiency of the energy generating system, (2) specific energy consumption for desalination, (3) specific emissions of CO₂, and (4) taxes on CO₂ emissions. The model presented can be applied for the analysis of schemes where seasonal surplus of unused power is utilized by RO which are characterized by higher efficiency of fuel consumption and decreasing specific CO₂ emissions.     

Promotion of energy conservation in developing countries through the combination of ESCO and CDM: A case study of introducing distributed energy resources into Chinese urban areas

The implementation of an energy service company (ESCO) project in developing countries may result not only in reduced energy cost but also in considerable environmental benefits, including the reduction of CO₂ emissions, which can be assessed in an economic manner under the Clean Development Mechanism (CDM) scheme. In this way, the economic and environmental benefits of energy conservation activities can be enjoyed by both the investor and the end-user, which can reduce the investment risk and realize a rational profit allocation. This study presents a numerical analysis of the introduction of distributed energy resources (DER) into a Chinese urban area. An optimization model is developed to determine the energy system combination under the constraints on the electrical and thermal balances and equipment availability. According to the simulation results, the introduction of DER systems possesses considerable potential to reduce CO₂ emissions, especially when considering that the economic profit of the CO₂ credit will increase the incentive to adopt DER systems to an even greater extent. Furthermore, by sharing the energy cost savings with the investors under an ESCO framework, the investment risk can be further reduced, and the conditions required for the project to qualify for CDM can be relaxed.     

Spatial variation of emissions impacts due to renewable energy siting decisions in the Western U.S. under high-renewable penetration scenarios

One of the policy goals motivating programs to increase renewable energy investment is that renewable electric generation will help reduce emissions of CO₂ as well as emissions of conventional pollutants (e.g., SO₂ and NO_x). As a policy instrument, Renewable Portfolio Standards (RPS) encourage investments in wind, solar and other generation sources with the goal of reducing air emissions from electricity production. Increased electricity production from wind turbines is expected to displace electricity production from fossil-fired plants, thus reducing overall system emissions. We analyze the emissions impacts of incremental investments in utility-scale wind power, on the order of 1 GW beyond RPS goals, in the Western United States using a utility-scale generation dispatch model that incorporates the impacts of transmission constraints. We find that wind investment in some locations leads to slight increases in overall emissions of CO₂, SO₂ and NO_x. The location of wind farms influences the environmental impact by changing the utilization of transmission assets, which affects the overall utilization of power generation sources and thus system-level emissions. Our results suggest that renewable energy policy beyond RPS targets should be carefully crafted to ensure consistency with environmental goals.     

Can carbon emission trading scheme achieve energy conservation and emission reduction? Evidence from the industrial sector in China

Whether the emission trading scheme (ETS) can achieve energy conservation and emission reduction in developing countries is crucial for these countries to achieve sustainable economic and environmental development. This study investigates the energy conservation and emission reduction effects of China's carbon dioxide (CO₂) ETS pilot policy implemented in 2011. Based on panel data of the two-digit industry at province level from 2005 to 2015, we adopt the difference-in-differences (DID) model to examine the effects of the CO₂ ETS on energy conservation and emission reduction. The results show that the CO₂ ETS decreases the energy consumption of the regulated industries in pilot areas by 22.8% and the CO₂ emissions by 15.5% compared to those in nonpilot areas. Further analysis indicates that the policy effects are mainly driven by improving technical efficiency and adjusting industrial structure. In addition, we find that the CO₂ ETS performs better in areas with high levels of environmental enforcement and marketization. Overall, our findings suggest that the CO₂ ETS has achieved energy conservation and emission reduction effects in developing countries.     

Optimization of the design of polygeneration systems for the residential sector under different self-consumption regulations

Polygeneration systems enable natural resources to be exploited efficiently, decreasing CO₂ emissions and achieving economic savings relative to the conventional separate production. However, their economic feasibility depends on the legal framework. Preliminary design of polygeneration systems for the residential sector based on the last Spanish self-consumption regulations RD 900/2015 and RD 244/2019 was carried out in Zaragoza, Spain. Both regulations were applied to individual and collective installations. Several technologies, appropriate for the energy supply to residential buildings, for example, photovoltaics, wind turbines, solar thermal collectors, microcogeneration engines, heat pump, gas boiler, absorption chiller, and thermal and electric energy storage were considered candidate technologies for the polygeneration system. A mixed integer linear programming model was developed to minimize the total annual cost of polygeneration systems. Scenarios with and without electricity sale were considered. CO₂ emissions were also calculated to estimate the environmental impact. Results show that RD 900/2015 discourages the investment in self-consumption systems whereas the RD 244/2019 encourages them, especially in renewable energy technologies. Moreover, in economic terms, it is more profitable to invest in collective self-consumption installations over individual installations. However, this does not necessarily represent a significant reduction of CO₂ emissions with respect to individual installations since the natural gas consumption tends to increase as its unit price decreases because of the increase of its consumption level. Thus, more appropriate pricing of natural gas in residential sector, in which its cost would not be reduced when increasing its consumption, would be required to achieve significant CO₂ emissions reduction. In all cases, the photovoltaic panels (PV) are competitive and profitable without subsidies in self-consumption schemes and the reversible heat pump (HP) played an important role for the CO₂ emissions reduction. In a horizon to achieve zero CO₂ emissions, the net metering scheme could be an interesting and profitable alternative to be considered.     

Environmental benefits of distributed generation with and without emissions trading

The need for improving energy efficiency and reducing CO₂ emissions and other pollutants, as well as the restructuring of energy markets has favoured the increase of distributed energy resources (DER). The co-ordinated control of these sources comprising renewable energy sources (RES) and distributed generators (DG) characterised by higher efficiencies and lower emissions compared to central thermal generation, when based on coal or oil provide several environmental benefits. These benefits can be quantified based on DER participation in the CO₂ emission trading market. This paper provides a method to calculate emissions savings achieved by the marginal operation of DER in liberalised market conditions using available emissions data. The participation of DER in emissions trading markets is also studied, with respect to profits, pollutants decrease and change in operating schedules. It is shown that the operation of DER can significantly reduce pollutants, provided sufficient remuneration from CO₂ emission trading market participation is provided. Moreover, it is shown that using average emissions values to calculate the environmental benefits of DER might provide misleading results.     

The effects of environmental regulation and technical progress on CO2 Kuznets curve: An evidence from China

Based on environmental Kuznets curve theory, a panel data model which takes environmental regulation and technical progress as its moderating factors was developed to analyse the institutional and technical factors that affect the path of low-carbon economic development. The results indicated that there was a CO₂ emission Kuznets curve seen in China. Environmental regulation had a significant moderating effect on the curve, and the inflection of CO₂ emissions could come substantially earlier under stricter environmental regulation. Meanwhile, the impact of technical progress on the low-carbon economic development path had a longer hysteresis effect but restrained CO₂ emission during its increasing stage and accelerated its downward trend during the decreasing stage which was conducive to emission reduction. Strict environmental regulation could force the high-carbon emitting industries to transfer from the eastern regions to the central or the western regions of China, which would make the CO₂ Kuznets curve higher in its increasing stage and lower in its decreasing stage than that under looser regulation. Furthermore, energy efficiency, energy structure, and industrial structure exerted a significant direct impact on CO₂ emissions; we should consider the above factors as essential in the quest for low-carbon economic development.     

What proportion of renewable energy supplies is needed to initially mitigate CO2 emissions in OECD member countries?

In spite of increasing numbers of countries having established renewable energy development mechanisms for carbon dioxide (CO₂) emissions reduction, the CO₂ emissions problem continues to worsen along with the growth of the world economy. This leads us to examine the threshold effect of the proportion of renewable energy supply for CO₂ emissions reduction by means of the panel threshold regression model (PTR). Economic growth and the price of energy are also both taken into account in the model in measuring the specific influence that each of them has on CO₂ emissions. The empirical panel data encompass all 30 member countries of the OECD and cover a period of about a decade in length from 1996 to 2005. Our empirical results provide clear evidence of the existence of a single threshold effect that may be divided into lower and higher regimes. Based on the specific estimates of the slope coefficients in each regime distinguished, we find that a renewable energy supply accounting for at least 8.3889% of total energy supply would mean that CO₂ emissions would start to be mitigated. Furthermore, real GDP and the CPI of energy are significantly and positively and insignificantly and negatively correlated with CO₂ emissions, respectively. These findings lead us to conclude that the authorities ought to enhance the proportion of renewable energy supply to more than 8.3889% of all energy supplied, which might help resolve the dilemma between economic growth and CO₂ emissions. Realizing the effects of CO₂ emissions reduction via energy price reforms or the levying of a carbon tax levy may, however, still remain a puzzle.     

Biomass energy,technological progress and the environmental Kuznets curve: Evidence from selected European countries

We examine the causal relationship between economic growth and CO₂ emissions in a panel of 24 European countries from 1980 to 2010. Using an analytical framework that considers pooled mean group estimations in a dynamic heterogeneous panel setting, we show that there is an inverted U-shaped relationship between CO₂ emissions and economic growth in the long run and that there is no such relationship in the short run. In particular, we find that biomass energy is insignificantly linked to CO₂ emission. However, technological innovation significantly facilitates reduction of CO₂ emissions in the investigated countries. Altogether, our study implies that economic growth and environmental quality can be achieved simultaneously, which opens up new insights for policy-makers for sustainable economic development via implementation of renewable energy consumption through technological innovation.     

Environmental and economic evaluation of ammonia as a fuel for short-sea shipping: A case study

In this study, the environmental and economic effects of the ammonia-diesel dual-fuel engine are evaluated by a case study with the real voyage data of a ship. Thirteen scenarios are formed by three different fuel fractions and three different types of ammonia which are classified according to their production routes (brown, blue, and green ammonia). Brown ammonia has worse (137.7%) or slightly lower (3%) CO₂ emissions than MDO depending on the feedstock. Blue ammonia complies with the IMO 2030 target with a 42.8% CO₂ reduction while green ammonia from solar energy has a similar reduction capacity with blue ammonia, and green ammonia from wind energy provides 79.2% CO₂ reduction and complies with the 2050 target. SO_X and PM emissions are decreased up to 95% by ammonia usage. NO_X emissions are 19.4% lower at 60% ammonia energy fraction than MDO, but it increases 133.1% at 95% ammonia energy fraction. The selective catalytic reduction system is required for high ammonia energy fraction cases. The N₂O emission is an important issue during ammonia usage. The fuel expense analyses show that brown ammonia is cheaper and blue ammonia is slightly higher (8.8%–13.9%) than MDO. Green ammonia does not be feasible recently, due to its significantly high price.     

China's 2020 carbon intensity target: Consistency,implementations, and policy implications

China has pledged to reduce its CO₂ emissions per unit of GDP by 40–45% by 2020 as of 2005 level. This research examines China's 2020 carbon intensity target and its interdependence with the overarching national economic and social development goals. The results show that, with annual GDP growth rate at 7% during the 12th Five-Year-Plan (FYP) period and 6% during the 13th FYP period, the 45% CO₂ intensity reduction target implies annual CO₂ emissions of 8600 million tonnes by 2020, close to 8400 million tonnes, the UNFCCC 450 ppm scenario for China. However, achieving only the 40% reduction target will lead to 9380 million tonnes CO₂ emissions in 2020 which largely surpass the UNFCCC 450 ppm scenario. We conclude that China's 45% CO₂ intensity reduction target is not only within international expectations but also self-consistent with its overall economic and social development strategy. Then primary energy and power planning for implementing the 45% carbon intensity reduction target is proposed. Related investment requirements are also estimated. To achieve the target, China needs to restructure the economic structure for significant improvements in energy conservation.     

Electricity savings and CO2 emissions reduction in buildings sector: How important the network losses are in the calculation?

The increase of CO₂ emissions and the emerging climate change are the most serious environmental problems nowadays and limit economic development. This increase is mainly attributed to the growing world population and the related growth in energy demand, which results in the vast consumption of fossil fuels in the power generation sector. Significant actions for the implementation of energy saving measures have been adopted worldwide for reducing greenhouse gas emissions. CO₂ calculators have been developed to evaluate the effectiveness of these measures, relating energy to CO₂ emissions. These calculators include in most cases the entire power system. The purpose of this work was to evaluate the role of the electricity networks' losses in the actual CO₂ reduction potential, following the implementation of energy saving measures, in relation to the network's voltage level in which the infrastructure is connected. Buildings are representative due to their volume and to different voltage levels of power supply. The work presented was conducted in the framework of the Intelligent Energy Europe Programme entitled Bottom Up to Kyoto (BUtK), as a part of an evaluation of the CO₂ emissions' reduction potential through energy savings measures in 6 municipalities of EU's New Member States.     

India’s energy needs and low carbon options

India’s aspiration for economic growth has consequences for energy growth and CO₂ emissions. This paper examines India’s need for energy with 20 year perspectives. From an earlier paper by K. Parikh et al. (2009), demand scenario are examined from the supply perspectives ranging from coal, hydrocarbon, nuclear, hydrogen, hydro and other renewable etc. None of these are substantial and India will have to rely on imports. The need for energy has to be reduced by a drive for energy efficiency and renewable energy. Government programmes for the above are also commented upon. Though India’s CO₂ emissions are unlikely to grow very much due to energy scarcity and energy mix the article examines the potential to reduce CO₂ emissions and the associated costs involved in various options. It finds that 30% reduction in CO₂ emissions by 2030 is feasible but would involve additional costs. The most promising option is to reduce energy demand by various measures to increase energy use efficiency in production and consumption.     

Insight into the Greek electric sector and energy planning with mature technologies and fuel diversification

The numerous available options for the development of the Greek electric sector in combination with the various techno-economic and political constraints make energy planning rather complex. Furthermore, as full auctioning of CO₂ allowances shall be the rule from 2013 onwards for the electric sector following free allocation, even more uncertainties emerge. This work aims at investigating the main characteristics of the Greek electric system taking into consideration the various allowance allocation schemes, evaluates fundamental energy scenarios and ultimately performs energy planning. The reliability of the algorithm utilised is assessed by predicting successfully key figure energy results for years 2004–2008. Main parameter under investigation in the study is the cost of CO₂ emissions allowances, while expansion scenarios are evaluated according to a newly developed set of indices standing for feasibility, environmental performance, cost effectiveness and energy safety. Many expansion scenarios examined were proved unrealistic as led to extremely high utilization of imported fuels for electricity production, while others proved inefficient on environmental or economic basis. Finally, it was proved that if a “conservative” energy planning is adopted, emissions reduction in 2020 can reach 6.3% over 2005.