Certified Emission Reductions Research Articles

Case Study of Calculating Carbon Credits for Municipal Solid Waste Incineration Power Generation

By replacing landfilling with municipal solid waste incineration, the emission of greenhouse gases (GHGs) generated by sanitary landfilling is avoided. Simultaneously, the thermal energy generated by waste incineration is utilized for power generation, replacing an equivalent amount of electricity generated from fossil fuels, thereby reducing greenhouse gas emissions. Taking a certain municipal solid waste incineration project as an example, relevant methodologies ACM0022 and CM-072-V01 are applied, and simulated calculations of Certified Emission Reductions (CCER) are conducted through national verification. Combined with the current carbon trading prices, additional value-added benefits are calculated, providing a reference for exploring growth opportunities for waste incineration power plants and achieving carbon peak and neutrality targets for the power plants.

Cost, market, and policy constraints on mitigating climate change through afforestation in China

Afforestation is a promising nature-based climate solution for mitigating climate change, but it is subject to a complex web of biophysical, cost-benefit, market, and policy processes. Although its biophysical feasibility has been established, the cost, market, and policy constraints that affect climate change mitigation through afforestation are still unclear. Here, we estimate such cost, market, and policy constraints on the basis of biophysical feasibility. Our findings reveal that implementation costs are a more relevant constraint than opportunity costs on mitigating climate change through afforestation. The China Certified Emission Reduction market currently provides only a 0.308 % incentive for climate change mitigation through afforestation, due to market access constraints. The current market prices of China Certified Emission Reduction, China Carbon Emissions Trading Exchange, and Nature Based Carbon Offset in Voluntary Carbon Market constrain 88.15 %, 87.95 %, and 85.75 % of CO2 removal actions through afforestation, compared to the carbon price scenario (US$62.97 tCO2-1) of the EU Emissions Trading System. Moreover, land policy under the scenarios of prohibiting conversion of cultivated land to forest and forest restoration in degraded areas exhibit 8.87–29.59 % and 65.16–74.10 % constraints, respectively, on mitigating climate change through afforestation compared to land-use freedom conversion scenarios from 2020 to 2060. Thus, enhancing the incentive price of CO2 removal, addressing the market access barrier, strengthening cooperation between global carbon markets, and exploring carbon–neutral and food multi-oriented land policies can be valuable sources of mitigation efforts over the next 40 years.

Pricing of Chinese Certified Emissions Reduction Scheme in a Supply Chain Under the Cap-and-Trade Policy

Abstract Against the backdrop of carbon trading, the Chinese Certified Emissions Reduction (CCER) scheme is one of the most important measures of China to reduce carbon emissions. We study a supply chain consisting of a CCER supplier and a manufacturer that buys CCER quotas from the supplier. The supplier is a non-emissions-control enterprise engaged in clean energy projects, while the manufacturer is classified into three types: a clean, a relatively clean, and an unclean firm. We analyse the impacts of the price and offset rate of CCER quotas on firms’ emissions reductions. We find that when the price of CCER quotas is lower than the price of Chinese Emissions Allowances (CEAs): (1) for both clean and unclean manufacturers, with increasing CCER offset rate (quota price), technical emissions reduction decreases (increases). (2) The incentive for the relatively clean manufacturer to reduce emissions is not affected by other extraneous factors. When the prices of CCER quotas and CEAs are uncertain, we find that (1) the technology abatement decisions of the three types of manufacturer are consistent and the corresponding CCER suppliers price their CCER quotas in the same way. (2) When the proportion of CCER quotas purchased by the manufacturer increases, the unit technical emissions reduction increases. Confirming that introduction of the CCER scheme can reduce carbon emissions, our findings provide theoretical guidance for suppliers to make pricing decisions on CCER quotas and for manufacturers to make technical emissions reduction decisions.

Mutual conversion mechanisms for environmental interest products to jointly enhance synergistic effect between power, CET and TGC markets in China

The construction of mutual conversion mechanisms for environmental interest products (EIP) is crucial to enhance connectivity and promote the synergistic development among multiple market systems including power, carbon emissions trading (CET) and tradable green certificate (TGC). In this paper, static and dynamic TGC‑carbon allowance (CA)-Chinese certified emission reduction (CCER) conversion mechanisms are designed from the perspective of physical and economic values. Based on the multi-agent dynamic game model considering Weber-Fechner's law, the transaction behavior for various generation companies (GENCOs) and power purchasers in power, CET and TGC markets under different conversion mechanisms are analyzed. The results demonstrate that TGC-CA-CCER conversion mechanisms further expand the transaction space for low-carbon GENCOs, and effectively reflect the differentiated value of each EIP in diverse scenarios and time periods. Compared with other conversion mechanisms, the dynamic TGC-CA-CCER conversion mechanism based on physical values has better economic as well as environmental benefits, and enhances the competitiveness and liquidity of markets, which is the optimal solution to realize the mutual conversion of EIP. These insights can make up for the research gap of mutual conversion mechanisms on different EIP and provide mechanism options for realizing favorable interaction among power, CET and TGC markets.

Forestry offsets under China’s certificated emission reduction (CCER) for carbon neutrality: regulatory gaps and the ways forward

PurposeAs a typical nature-based solution to climate change, forestry carbon sinks are vital to achieving carbon neutrality in China. However, regulations in China are insufficient to promote the development of carbon offset projects in forestry. This study aims to identify the regulatory obstacles impeding the development of forestry offsets under China’s certified emission reduction (CCER) and explore ways to improve the regulatory system.Design/methodology/approachThis study conducts a qualitative analysis using a normative legal research method. This study conducted a synthetic review of national and local regulatory documents to gain insights into the regulatory landscape of forestry offsets in China. The main contents and characteristics of these documents are illustrated. Furthermore, related secondary literature was reviewed to gain further insight into forestry offset regulations and to identify significant gaps in China’s CCER regulation.FindingsForestry offset regulations under the CCER are characterized by fragmentation and a relatively lower legally binding force. There is no systematic institutional arrangement for forestry offset development, impeding market expectations and increasing transaction costs. The main challenges in China’s regulation of forestry carbon sinks include entitlement ambiguity, complicated rules for registration and verification, a lack of mechanisms for incentives, risk prevention and biodiversity protection.Originality/valueForestry carbon sinks’ multiple environmental and social values necessitate their effective development and utilization. This study assessed forestry offset regulations in China and proposed corresponding institutional arrangements to improve forestry carbon sink regulations under the CCER.

Clean Development Mechanism: Indian Step Sustainable Environment

The Kyoto Protocol established the Clean Development system (CDM), a cooperative system that might help developing nations achieve sustainable development by encouraging environmentally conscious investment from firms and governments in affluent nations. An overview of the CDM's history, composition, and project cycle is given in this publication, which also looks at the benefits and potential value for participating developing nations like India. The Ozone layer is being weakened by pollution brought on by an increasing population. On our earth, every species is in danger of being extinct. The primary conclusions are: With the aid of the Kyoto Protocol, three formal methods for global emission reduction were established: Joint Implementation (JI), Clean Development Mechanism (CDM), and International Emissions Trading (IET). It raises public awareness, and with the aid of certified emission reduction units, some environmental organizations developed the idea of carbon trading. The CDM offers both industrialized and developing nations a win-win scenario. Businesses in India such as Gujarat Fluoro Chemicals, Tata Steel, NTPC, ONGC, and others can obtain several facilities abroad by using CERs. Through the exchange of credits and reduction of GHG emissions, carbon trading and CER "claims" to avert the impending disaster. Therefore, it can be concluded that imposing carbon prices with refunds is an effective strategy to address the pre-existing issue. Since reducing greenhouse gas (GHG) emissions is a worldwide public good and the location of emission reductions has no bearing on the global stock of GHG, the CDM's premise is that reductions in emissions should be made where they can be done for the least amount of money. The findings shed light on potential difficulties in navigating market mechanisms in the future and show how the Carbon Offset Management (CDM) program has provided nearly 20 years of knowledge and expertise in the area of global carbon offset governance.

Impact of introducing Chinese certified emission reduction scheme to the carbon market: Promoting renewable energy

The China Certified Emission Reduction scheme (CCER) and the Cap-and-Trade (CaT) mechanisms jointly constitute the Emission Trading Scheme (ETS), which is expected to have a profound impact on China's social and economic decarbonization. However, previous studies have primarily focused on the impact of the CaT mechanism, neglecting the fact that CCERs serve as a carbon offset trading mechanism. This paper focuses on the impact of the CCER mechanism on China's energy economy and environment by constructing a recursive dynamic computable general equilibrium model that couples CaT and CCER mechanisms. Introducing the CCER mechanism based on the CAT mechanism leads to increased output and reduced prices in renewable energy sectors, cascading positive effects across various energy-utilizing sectors to counter the decline in Gross Domestic Product (GDP) and residential welfare. The finding suggests that China's unique CCER mechanism is poised to play a more important role in promoting renewable energy to mitigate global warming, given its potential to transform the structure of energy production and consumption. Finally, targeted policy recommendations are proposed for implementing the CCER mechanism.

Comparison of Chinese Green Electricity Certificate and International Green Electricity Certificate

This paper sorts out the trading mechanisms of GECs (Green Electricity Certificate of China) and international Green Electricity Certificate, analyzes the characteristics of relatively mature international Green Electricity Certificate trading mechanism, and compares and analyzes GECs and international Green Electricity Certificate trading mechanism from four aspects: price, issuance scope, trading process and recognition degree. The existing problems of GECs trading mechanism are found, and suggestions are put forward to optimize the GECs trading mechanism from four aspects: increasing the demand for GECs, establishing a collaborative mechanism between GECs and CCER (Chinese Certified Emission Reduction) market, strengthening the traceability of GECs and promoting the international certification of GECs.

Analysis of Clean Development Mechanism for Dernah Wind Farm (I) Project (Libya) by Using AM0019 Methodology

Since the Kyoto Protocol came into effect on Feb 16, 2005, the Clean Development Mechanism (CDM) has experienced significant global growth. This mechanism enables developing countries to actively engage in combating climate change by implementing projects aimed at reducing Greenhouse Gas Emissions (GGEs). In 2010, Libya established the Commission of the Designated National Authority (DNA) to oversee the implementation of the CDM. This move was made as part of Libya's efforts to develop a range of projects that qualify for CDM and contribute to reducing GGEs. The main motivation for conducting this study was the absence of Libya's involvement in global-level CDM projects, as evidenced by the United Nations Framework Convention on Climate Change (UNFCCC) annual reports. Additionally, the failure to recognize the significance of CDM in influencing decisions regarding investments in wind energy. This work aims to investigate the use of CDM in Dernah wind farm (I) project (Libya). The study used a suitable CDM methodology, AM0019 with the appropriate tool (03-V3), calculated as CO2 reductions and Certified Emission Reductions (CERs).
 The results of CDM analysis are as follows: CO2 reductions = 362,201.82 tCO2e/year and CERs for the first ten years of the age of the proposed wind farm (Dernah Wind Farm (ɪ)) (CERs10y) = 1,687,898,590 LD (320,838,371.8 €) for the first ten years, likewise CERs20y= 3,375,797,180 LD (641,676,743.5 €) during the entire life (20 years) of the proposed wind farm. Based on these results, it can be concluded that the project will be highly cost-effective, this will lead to lower electricity prices for consumers and higher profits for the project owners. Therefore, registering wind energy projects as CDM projects and earning CERs is the most practical way to promote wind energy. The findings of this study could be valuable for policy makers and project developers who are interested in CDM wind projects.

Forest emissions reduction assessment from airborne LiDAR data using multiple machine learning approaches

Objective: This study aims to evaluate the accuracy of different modeling methods and tree structural parameters extracted from airborne LiDAR for estimating carbon emissions reduction and assess their reliability as Certified Emission Reduction (CER) assessment techniques.Methods: LiDAR data was collected from an afforestation project in Beijing, China. Various modeling methods, including statistical regression and machine learning algorithms, were used to estimate biomass and carbon emissions reduction. The models were evaluated under two schemes: tree-species-specific modeling scheme (Scheme 1) and all-sample modeling scheme (Scheme 2) using cross-validation and compared with ground-based estimations and pre-estimated emission reductions.Results: Totally, the biomass estimation models in scheme 1 showed better accuracy than scheme 2. In scheme 1, The Random Forest (RF) and Cubist models achieved the highest prediction accuracy (R2 = 0.89, RMSE = 22.87 kg, CV RMSE = 52.00 kg), followed by GDBT and Cubist, with SVR and GAM performing the weakest. In scheme 2, Cubist model had the highest accuracy (R2 = 0.75, RMSE = 33.95 kg, CV RMSE = 36.05 kg), followed by RF and GBDT, with SVR and GAM performing the weakest. LiDAR-based estimates of carbon emissions reduction were closer to ground-based estimations and higher than pre-estimated values.Conclusion: This study demonstrates that LiDAR-based models using tree structural parameters can accurately assess carbon emissions reduction. The models outperformed traditional methods in terms of cost and accuracy. Considering tree species in the modeling process improved the accuracy of the models. LiDAR technology has the potential to be a reliable assessment technique for carbon emissions reduction in forestry projects. The pre-trained models can be used for multiple predictions, reducing the cost of carbon sink surveys. Overall, LiDAR-based models provide a promising approach for assessing carbon emissions reduction and can contribute to mitigating climate change.

A carbon trading approach for heat-power-hydrogen integrated energy systems based on a Vickrey auction strategy

Exploring the way of the integrated heat-power‑hydrogen energy system (CHHP) participates in carbon trading is important for reducing carbon emissions and achieving carbon peaking and carbon neutrality goals. To fully consider the potential for renewable energy to participate in the carbon trading market through Chinese certified emission reductions (CCERs), this paper proposes a carbon trading method for CHHP based on a Vickrey auction strategy. Firstly, the model of CHHP is built by considering the waste heat of the hydrogen power generation system. The calculation of CCERs of hydrogen and other renewable energy sources is then studied based on calorific value and combined marginal emission factors. Meanwhile, given the zero carbon of renewable energy sources and the large difference in price between Chinese emission allowances (CEAs) and CCERs. For traditional energy sources, a baseline approach is used to allocate CEAs to carbon sources. A price-fixed trading model for CEAs is established considering actual carbon emissions; For the CCERs from hydrogen and other renewable energy, a trading mechanism based on a Vickrey auction has been introduced. Finally, the proposed method is analyzed in three scenarios. The approach proposed in this paper results in lower system operation costs and more favorable planning for low-carbon emission output equipment. The results show that the proposed trading method has advantages in the economy and carbon emissions.

How to promote the Chinese Certified Emission Reduction scheme in the carbon market? A study based on tripartite evolutionary game model

The Chinese Certified Emission Reduction (CCER) scheme is of great significance for China to achieve its “dual carbon” targets. However, limited effort has been made to explore the CCER scheme due to poor data availability and the short implementation time. Therefore, this study constructs a tripartite evolutionary game model involving the government, carbon emission control enterprise, and renewable energy enterprise, to analyze the evolutionary stability of each subject's strategy choice. The results indicate that: (1) Strict regulation of the government could promote carbon emission control enterprise to actively purchase CCER quotas, and motivate renewable energy enterprise to declare CCER projects. (2) When the corresponding condition is met, the system could reach the ideal evolutionary steady state of (1,1,1), and keep a stable operational status for the CCER scheme market. (3) The condition of the CCER price below the carbon price, appropriate penalties for non-compliance of carbon emissions, the dynamic balance between carbon offset rate and project declaration cost, and proper subsidies for CCER project declaration, all could promote the development of CCER projects in the carbon market. This study could enrich the knowledge hierarchy of CCER and provide important decision references for developing the CCER scheme in the carbon market.

A bi-level scheduling strategy for integrated energy systems considering integrated demand response and energy storage co-optimization

In the context of China's “double carbon” commitment to the world, the introduction of integrated demand response mechanism and compressed air energy storage system into the traditional energy system is important to improve its structure, promote the interaction of multiple heterogeneous energy sources, and improve energy conversion efficiency. As such, in this study, we constructed an upper-layer capacity configuration model aiming to optimize the operating costs of compressed air energy storage systems during the planning period and subsequently integrated a heterogeneous energy network operation and China's certified emission reduction constraints under various operating scenarios. We established a lower-level optimal scheduling model with the optimization objective of minimizing the energy purchase, operation, maintenance, integrated demand response subsidy, and carbon trading costs. Finally, the KKT condition and the Big M method were used to solve this two-tier optimization problem. The comparative analysis of the three schemes showed that, under the consideration of the integrated demand response mechanism and the equipped compressed air energy storage system, the total operating cost of the system was reduced by an average of 2.28 %, the carbon emission was reduced by an average of 7.17 %, the profit from the sale of surplus carbon emission credits increased by an average of 16.7 %, and the energy storage capacity was reduced by approximately 39 %. Thus, this method effectively reduced the capacity of the energy storage system and significantly improved its reliable, economic, and low-carbon operation.

Research Progress and Prospect of Tourism Carbon Emissions and Its Uncertainty Analysis Under the Goal of Low-Carbon Scenic Spots

Under the dual carbon goal, China Certified Emissions Reductions (CCER) and the national carbon market have become important means of emission reduction and control. The tourism industry is a strategic pillar industry of China’s national economy, and scenic spots are the main sites of tourism activities. Research on carbon emissions in scenic spots is of great significance for the construction of low-carbon scenic spots and the realization of the dual carbon goal. In this paper, the research on carbon emissions in tourism is reviewed, the current research progress is discussed, and further prospects are made. The research on tourism carbon emissions in China has a good foundation and achieved certain results. However, there are few studies on micro-scales such as scenic spots. The statistical data caliber and measurement methods of carbon emissions are not uniform, and there is a general lack of uncertainty analysis. Future research should focus on building a multi-spatial dimension research system, unifying the statistical caliber and measurement methods of carbon emission data, increasing uncertainty analysis, and ensuring the robustness of research results.

Has Chinese Certified Emission Reduction trading reduced rural poverty in China?

AbstractConsolidating and expanding poverty alleviation while simultaneously reducing carbon emissions has become one of the main issues facing China. The Chinese Certified Emission Reduction (CCER) trading programme is an important supplementary mechanism to China's carbon trading market. Based on the data of 1782 counties in China from 2006 to 2017 and a difference‐in‐differences model, this study investigates the rural poverty reduction effect of CCER trading. We find that: (1) during the sample period, CCER trading has increased the per capita net income of rural residents by at least 2.5% or 187.5 RMB (about 27.8 USD or 39.3 AUD) per year. (2) The poverty reduction effect of CCER trading in poor counties is greater than that in nonpoor counties. (3) Some relevant heterogeneous effects are also measured. We find that CCER trading of hydropower projects has played a significant poverty reduction effect; the poverty reduction effect is further enhanced when the county has additional CCER projects; we also identify regional differences with CCER trading having a greater poverty reduction effect in the western and central regions. (4) Compared with the implementation of the CCER project, trading the emission reductions generated by the CCER project has brought more significant poverty reduction effects.

China's forest carbon sinks and mitigation potential from carbon sequestration trading perspective

To achieve carbon peaking and neutrality goals, China is establishing a national unified carbon emission trading market, especially including forest carbon sequestration market. This study assesses the potential of China’s forest carbon sinks and mitigation potential. We use the Global Forest Products Model to simulate the dynamic changes in China's forest resources from 2018 to 2060, under different carbon sequestration prices scenarios. The projection results indicate that China's forest carbon sinks will be 1.26 Pg (peta-grams) in 2021–2030 and 6.78 Pg in 2021–2060, giving an offset ratio of 4.9–7.0 % and 13.2–18.2 % of China's projected carbon emission in the same period, respectively. Therefore, China's forest carbon sinks will play an important role in carbon peaking and neutrality goals. Meanwhile, forest carbon trading has the potential to increase China's forest carbon sequestration, although the impact may not be immediately apparent. The additional increase in forest carbon sinks from carbon sequestration trading scenarios will not exceed 1.6 % of China’s total carbon emissions between 2021 and 2030. At the current carbon trading price in China ($6.84/t), the increase in forest carbon sinks resulting from forest carbon trading will give an offset ratio of approximately 1 % of total carbon emissions from 2021 to 2060. When the carbon price rises, this offset ratio is 2.3 % to 3.1 % ($25/t), 4.1 % to 5.6 % ($54/t). China should therefore hasten the integration of forest carbon sinks into the national carbon emission unified market and boost the carbon trading price by policy design and market adjustment, or government directly compensate for the forest carbon sequestration function. For forest carbon sinks to play their role in reducing the carbon neutral cost of society, China should raise the amount of forest carbon sink CCERs (Chinese Certified Emission Reductions) used to offset carbon emission allowances in key emission units.

Asymmetric time-varying dependence and variable structure dependence measurement and analysis of EUA and CER

Abstract This paper analyzed the time-varying dependence and structural dependence between EU allowances (EUAs) and certified emission reductions (CERs) by using price fluctuation data from 2008 to 2021 on EU ETS. It was found that (1) there was a strong nonlinear spillover relationship between EUAs and CERs. From 14 March 2008 to 16 March 2012, the time-varying dependence values of EUAs and CERs were mostly between 0.6 and 1 and the mean coefficient of dependence was 0.86, showing a strong interdependence. From 17 March 2012 to 2 January 2017, the correlation between them was mostly below 0.6 and the mean coefficient of dependence fell to 0.25. This indicates that the dependency between EUA futures and CER futures was very low at this stage. However, in general, the mean value of dependence was above 0.55, that is, there was a dependency between them. (2) From 14 March 2008 to 2 January 2017, there were 12 structural mutation points in EUA and CER yield sequences. After four mutation points, the dependence coefficient increased and the structural dependence enhanced. Meanwhile, after eight mutation points, the dependence coefficient decreased and the structural dependence weakened. The overall level remained above 0.6, showing the existence of structural dependence. (3) Abrupt changes in EUA and CER prices were closely related to the promulgation of major policies and unpredictable emergencies. The former caused carbon prices to fluctuate slightly. When the period of change was short and the recovery was rapid, it caused sharp fluctuations in carbon prices. When the duration of change was long, and the recovery was slow, it yielded impacts that extend far beyond the publication of important information.

A split Bregman method solving optimal reactive power dispatch for a doubly-fed induction generator-based wind farm

This paper proposes an optimal reactive power control method to maximize wind farm revenue and minimize the total electrical losses of a doubly-fed induction generator (DFIG)-based wind farm. Specifically, the split Bregman method is used to solve the optimal control problem in a distributed manner. That is, the optimization problem is decomposed into sub-problems by the optimal distributed control strategy, and each sub-problem is solved independently in each local controller through the parallel method, which reduces the calculating burden and improves the information privacy. Thus, when a fault occurs, the proposed distributed control strategy can overcome the system fault and improve the reliability and security of the system. Furthermore, an economic financial model of annual revenue is contributed to examine the income impact with or without certified emission reduction (CER) by the clean development mechanism (CDM). Compared with the dual ascent (DA) method, sequential quadratic programming (SQP) method and the proportional dispatch method (PDM), the annual revenue (AR) of the wind farm using the proposed split Bregman method is the highest. Simulation results demonstrate that this method has promising performance in both optimization quality and computational efficiency.

Credit Analysis of Carbon Sink Ecological Compensation in P.R.C from the Perspective of Coase Theorem: An Empirical Analysis Based on Carbon Sink Financial Projects in X Village of Guangdong and Y Village of Zhejiang

The deterioration of the global environment and climate makes it historically important to achieve carbon peaking and carbon neutrality and plays an important role in promoting environmental protection. Among them, forestry carbon sink resources occupied an important role in China Certified Emission Reduction (CCER). While the development of carbon trading in China is still in its initial stage, the government is piloting it in some areas first, accumulating experience and gradually promoting it. This research analyzes the economic operation mechanism of the current carbon trading project such as the Green Carbon Credits, the management structure of CCER: How CCER can reduce the cost of emission reduction for enterprises and increase the flow of social wealth, how to make the development of forestry carbon sinks more widespread, and the potential directions for future development: how to make CCERs more widely available.

Paths and policy adjustments for improving carbon-market liquidity in China

Weak liquidity and low spot prices for carbon are critical problems facing China's carbon markets. This study aims to quantify the liquidity of China's carbon markets under different carbon-pricing strategies by analyzing a model which integrates linkages between the government, markets, and firms. It uses the decoupling theory to set the penalty scale, aiming to reduce the effects of carbon emissions on economic growth. The model permits the study of policy adjustments for certified emission reduction, traders' coverage, and free quotas — the benchmarks of quota allocation. The theoretical analysis indicates that the effect of policy on market liquidity is mainly reflected in the penalty scale and quota-allocation rules. Numerical simulations indicate that the issuance of new quotas accounts for 3.3% of total allocated quotas and raises carbon prices by about 45%. Further, the carbon price rises with an increase in free quotas and then rapidly drops after a peak price of 57 yuan/ton. Our findings indicate that adding free quotas in the short term and expanding trading volume in the middle and long term will improve market liquidity and raise carbon prices.