<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Do Commodities Determine the EU Emission Allowances Price?</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Kiel University of Applied Sciences</institution>
          ,
          <addr-line>Sokratesplatz 2, 24149 Kiel</addr-line>
          ,
          <country country="DE">Germany</country>
        </aff>
      </contrib-group>
      <fpage>0000</fpage>
      <lpage>0002</lpage>
      <abstract>
        <p>This paper presents an analysis of the influence of gas, coal, electricity and Brent (crude oil) prices on the EU emission allowance price by means of a vector autoregression analysis. Statistically significant influences on the price of CO2 emission allowances can be identified for all energy market variables examined, except electricity prices. Thus, the present analysis supports the assumptions of earlier publications that the influence of the energy market on the European Emissions Trading System (EU ETS) is decreasing and that the efforts of the European Commission are having an effect. The EU ETS is designed to stimulate the reduction of emissions by setting caps and to create monetary incentives for investment in new, low-emission technologies by trading emission allowances. However, the allocation efficiency of this system is conditional on the relative price stability of the emission allowances, as this is the only way to make reliable forecasts for risk calculations and investment decisions by companies. Using a vector autoregression model (VAR), this paper demonstrates significant influences of energy prices on the European Emission Allowances (EUA) price in the third phase of the EU ETS.</p>
      </abstract>
      <kwd-group>
        <kwd>CO2</kwd>
        <kwd>emission allowances</kwd>
        <kwd>emissions trading</kwd>
        <kwd>energy prices</kwd>
        <kwd>vector autoregression</kwd>
        <kwd>VAR</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>The European Emissions Trading System (EU ETS) was implemented in all 28 EU
member states on 1 January 2005. As a cap-and-trade system, it sets an upper limit for
the total amount of greenhouse gas emissions permitted in industry, but allows trading
of emission allowances between companies within this quota. The upper limits are set
individually by the EU member states with the aim of reducing the permitted emission
quantities over the course of the years [9].</p>
      <p>The possibility of buying and selling allowances allows companies that produce
particularly low greenhouse gas emissions to benefit, as they can sell surplus allowances
to other, less efficient companies. In a stable trading system, this can create incentives
for companies to invest in the conversion of their production facilities so that they can
refrain from purchasing emission allowances in the future. In a functioning market, the
prices of emission allowances thus reflect allocation-efficient investments in climate
protection.</p>
      <p>Copyright © 2020 for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).</p>
      <p>For the incentive systems described above to work, a stable market for emission
allowances is necessary. This became clear when the economic crisis of 2008 abruptly
reduced the CO2 emissions of companies, which in turn led to a massive oversupply of
emission allowances and caused the price of these to fall [9].
2</p>
    </sec>
    <sec id="sec-2">
      <title>Trading Periods of the EU ETS</title>
      <p>Emissions trading takes place in allocation phases lasting several years (see Fig. 1) in
order to compensate for fluctuations, for example as a result of extreme weather
conditions, and to create longer-term investment security. With each subsequent phase, the
system was successively implemented and stabilized in the market.</p>
      <p>Fig 1. The phases of the EU ETS.</p>
      <p>In Phase I, a price for carbon emissions was set that allows EU-wide trading and
sanctions for exceeding the ceilings were implemented. The emission allowances were
initially distributed to the companies free of charge, while at the same time an
infrastructure necessary for monitoring was created. In the absence of reliable emissions
data, estimates were used to determine the number of allowances to be issued. However,
as these were clearly too high, the price of the emission allowances fell to zero in 2007
[9].</p>
      <p>In Phase II, the quantity of allowances distributed free of charge was reduced, as
were the emission ceilings of the countries. In addition, three new countries, Iceland,
Liechtenstein and Norway joined the emissions trading scheme. The penalty price per
tonne of CO2 for exceeding the ceilings was more than doubled. However, due to the
economic crisis during this period, the price of emission allowances fell
significantly [9].</p>
      <p>In the currently ongoing third phase of the EU ETS (as of March 2020), the national
caps have been replaced by an EU cap. The emission allowances not distributed free of
charge will be auctioned and additional industrial sectors and emission gases will be
covered. In addition, the market stability reserve was introduced. As a short-term
solution, the auctioning of a total of 900 million allowances in 2014-2016 was postponed
to 2019 and 2020. The market stability reserve, which was implemented in January
2019, represents the long-term solution. In future, this reserve will absorb surpluses in
the allowances market in accordance with defined rules and, if necessary, distribute
allowances in the event of a shortage [9].</p>
      <p>A further reduction of the ceilings and further strengthening of the market stability
reserve is planned in Phase IV. In addition, from 2023 onwards, emission allowances
from years prior to the previous year of the current trading period are to expire [9].</p>
      <p>In order for the EU ETS to serve as an incentive scheme for investment in
technologies to reduce greenhouse gas emissions as described above, it is necessary that the
scheme provides a stable price. Only with this price as a basis can companies make
conscientious investment decisions. Thus, important practical implications can be
derived from this study.</p>
      <p>This paper will use vector autoregression analysis (VAR) to analyse the interactions
between the four most important energy prices, electricity, gas, Brent (crude oil) and
coal, and the price of emission allowances. These four factors represent important
economic indicators in the energy sector and are therefore suitable for examining the
vulnerability of the EU ETS to minor economic fluctuations. This study covers the period
from 30 September 2013 to 1 October 2019 and provides a more up-to-date analysis
than the existing literature. Furthermore, existing theories for phase III of the EU ETS
will be verified.</p>
      <p>The present work is structured as follows: In the next section a short overview of the
results of the existing literature is given. Based on the literature, hypotheses for the
investigation are derived. In the third section the sample and the chosen methodology
are presented. Then the results are discussed and a summary of the possible implications
of the results is given.
3
3.1</p>
    </sec>
    <sec id="sec-3">
      <title>Prior Research and Hypothesis Development</title>
      <sec id="sec-3-1">
        <title>Prior Research</title>
        <p>The literature on the dynamics and volatility of CO2 allowances has grown rapidly
during the first and second phase of the EU ETS (2005-2012) and flattened significantly
with the start of the third phase of the EU ETS in 2013. This may be due to the fact that
the system became established and prices have remained relatively constant since.
Since 2018, however, the EUA price has risen significantly, reaching a record high in
mid-August 2019, almost six times its September 2013 value. The variables influencing
the price of CO2 emission allowances identified in the literature to date are numerous
and vary in their intensity from phase to phase.</p>
        <p>Mansanet-Bataller et al. [16] concentrate in their work on the daily CO2 price
changes in 2005 in order to investigate the underlying rationality of price behaviour.
For this purpose, the authors have analysed influencing factors on both the supply and
the demand side of EUAs using different models. While the effects of national
allocation plans on the price level of CO2 emission allowances were not statistically
significant in an intervention analysis, the influence of energy and weather variables on CO2
price changes could be demonstrated. The authors applied OLS-regression and the
Newey-West covariance matrix estimator, among other techniques.</p>
        <p>
          Alberola et al. [
          <xref ref-type="bibr" rid="ref2">2</xref>
          ] have analysed the influences on the EUA price during the entire
pilot phase of the EU ETS (2005-2007). Using the OLS method, the authors postulated
an empirical relationship between changes in EUA prices and significant influencing
factors such as commodities (Brent, coal, gas), electricity prices and weather
conditions. The authors also show that the effects of the influencing factors on the EUA price
changed in the period 2005-2007 after two statistically determined structural breaks in
the EU ETS in April 2006 and October 2006, which were caused by the publication of
new market-relevant information. According to the authors, unforeseen temperature
changes in extreme weather conditions play a greater role in EUA price changes than
the temperatures themselves.
        </p>
        <p>
          Bredin and Muckley [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ] have investigated the extent to which several theoretically
based factors such as economic growth, energy prices and weather conditions
determined the expected prices for EUAs in the period 2005-2009. Using both static and
recursive versions of the multivariate cointegration probability ratio test, the authors
show that the EU ETS is a functioning market driven by these factors. Creti et al [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ]
confirm this result in a cointegrating framework by using the Dow Jones Euro Stoxx
50 as their stock variable.
        </p>
        <p>
          Aatola et al. [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ] have investigated the pricing of EUAs under the EU ETS and its
price development during the first five years (2005-2010). For this purpose, the authors
first developed a market equilibrium model for the emissions trading market and then
tested it empirically using time series econometrics. OLS, IV and VAR models were
applied. The time series of various EUA-related commodities and other relevant market
fundamentals, such as electricity, steel, paper and mineral products, were used as
explanatory variables. The authors were able to show that there is a clear and stable
relationship between energy prices and the EUA price. About 40% of the price changes in
the EUA futures price could be explained by these fundamentals. The most important
determinant of the EUA price is the price of electricity generated in Germany, which
has a large and significant influence on the EUA price. Other energy prices also
influence the EUA price in a statistically significant way, but to a lesser extent.
        </p>
        <p>
          Hintermann [13] investigated the interaction between the EUA price and marginal
abatement costs during the first phase of the EU ETS (2005-2007). He found that Brent
(crude oil) prices, electricity and economic growth indicators are important price
drivers. However, due to the shorter time span in the study, his estimates showed less
statistically significant coefficients than those of Aatola et al. [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ]. Hintermann [13] also
classified the coal price as not significant.
        </p>
        <p>
          Chevallier [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ] has investigated the interaction between EUA, energy and
macroeconomic variables by specifying and estimating several Markov-switching VAR models
for the period 2005-2010, extending in particular earlier work by Benz and Trück [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ]
on univariate Markov-switching modelling of EUA price series. In conclusion,
Chevallier [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ] found that the industrial development of a country has a positive influence on
the development of the EUA price. In upturns, the EUA price rises as the economy
picks up; in recessions, the EUA price falls as the capacity utilisation of manufacturing
companies increases. In addition, the author postulates the price of fuel as the most
influential variable, which shows influences on other energy prices in addition to the
EUA price.
        </p>
        <p>Hammoudeh et al. [12] use a quantile regression to investigate the effects of changes
in crude oil, natural gas, coal and electricity prices on the distribution of CO2 emission
allowance prices in the United States in the period from 2006 to 2013. The authors
found that an increase in the price of crude oil leads to a significant decrease in the price
of CO2 if it is very high; changes in the price of natural gas have a negative effect on
the price of CO2 if it is very low but a positive effect if it is high; the effects of changes
in the price of electricity have a positive effect on the price of CO2 in the right part of
the distribution and the price of coal has a negative effect on the price of CO2.</p>
        <p>
          In summary, previous research has shown that the level of the CO2 emission
allowances price is primarily regulated by the market mechanism of supply and demand on
national exchanges [
          <xref ref-type="bibr" rid="ref6 ref7">6, 7, 16</xref>
          ]. Numerous influencing factors on both the supply and the
demand side have been investigated in the literature.
        </p>
        <p>
          The supply side is determined by the number of allowances made available by the
state through national allocation plans (NAPs) in consultation with the European
Commission [
          <xref ref-type="bibr" rid="ref1 ref6">1, 6</xref>
          ]. A certain price or a lower or upper price limit can be set directly when
the allowances are made available. Furthermore, it is possible to influence the price of
CO2 emission allowances by regulating the quantity of allowances made available [12]
or by setting an upper emission limit below the usual commercial emission level [
          <xref ref-type="bibr" rid="ref2">2</xref>
          ].
        </p>
        <p>
          The demand side is characterised by a complex interaction of various influencing
factors. In addition to weather conditions (temperatures, precipitation and wind speeds)
[
          <xref ref-type="bibr" rid="ref2">2, 16</xref>
          ], economic activity (economic growth and activity on financial markets) [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ] and
the disclosure of institutional information [
          <xref ref-type="bibr" rid="ref2">2</xref>
          ], energy prices (coal, electricity, oil and
gas) are seen as the main influencing factor [
          <xref ref-type="bibr" rid="ref1 ref2 ref5 ref6">1, 2, 5, 6, 12, 13, 16, 17</xref>
          ].
        </p>
        <p>The following diagram provides an overview of the main factors on the supply and
demand side that influence the formation of the CO2 emission allowances price.
According to the existing scientific literature, the prices of Brent (crude oil), natural
gas, coal and electricity were chosen as the most calculable price influencers on the
price of emission allowances. In contrast to the existing literature, this study considers
the period from 30.09.2013 to 01.10.2019. The year 2013 marks the beginning of the
implementation of the third phase of the EU ETS, in which the instruments used led to
a relative stabilisation of the prices for emission allowances from 2018 onwards (Fig. 4)
and the interaction of the different market mechanisms.
3.3</p>
      </sec>
      <sec id="sec-3-2">
        <title>Hypothesis Development</title>
        <p>The following hypotheses can be derived from the results of the preceding literature:</p>
        <p>Hypothesis I (H1): The price of Brent (crude oil) has a negative impact on the EUA
price, since a high oil price reduces the demand for oil and thus greenhouse gas
emissions. Consequently, an increase in the price of crude oil leads to a decrease in the price
of CO2 emission allowances [12].</p>
        <p>
          Hypothesis II (H2): The coal price also has a negative influence on the EUA
price [
          <xref ref-type="bibr" rid="ref1 ref2">1, 2, 12</xref>
          ]. If the coal price rises compared to other energy markets, companies
have an incentive to change their energy mix to less CO2-intensive energy sources.
        </p>
        <p>
          Hypothesis III (H3): In the literature, the gas price is generally associated with a
positive influence on the EUA price [
          <xref ref-type="bibr" rid="ref1 ref2">1, 2, 16</xref>
          ]. Hammoudeh et al. [12] differentiate
further and state that an increase in natural gas prices has a negative effect on the EUA
price if it is very low, while an increase has a positive effect if the EUA price is high.
This effect is mainly related to the high degree of substitutability between gas and coal,
which was also found in further investigations [
          <xref ref-type="bibr" rid="ref2">2, 12, 16</xref>
          ].
        </p>
        <p>
          Hypothesis IV (H4): According to prevailing opinion, the electricity price has a
positive influence on the price of EUA [
          <xref ref-type="bibr" rid="ref1 ref2">1, 2</xref>
          ]. According to Aatola et al. [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ], the price
of electricity produced in Germany is even the most important factor influencing the
EUA price. According to Hammoudeh et al. [12], a positive influence of electricity on
the CO2 emission allowances price can only be assumed if the CO2 emission allowances
price is high, but in general a negative influence can be assumed.
        </p>
        <p>The following Figure 3 shows the influences of the four energy sources (coal,
electricity, Brent and gas) on the EUA price as established in the previous literature.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>Data and Methodology</title>
      <sec id="sec-4-1">
        <title>Data</title>
        <p>In the present study, working day data from the period 30 September 2013 to 1 October
2019 are taken into account. This covers only phase III of the EU ETS, which started
in 2013 and ends in 2020. The time series data were obtained from Thomson Reuters
Datastream and contain 1567 observations per variable. Figure 4 shows the
development of the observed prices over time. Tables 1 and 2 show basic statistics of the time
series before and after the first differences were calculated. The correlation matrix on
the basis of the first differences in Table 3 shows consistently positive correlations with
mostly high significance.</p>
        <p>Fig 4. Time series diagrams.
The daily spot prices (in €/t) of the European Energy Exchange (EEX) are used for the
price of EUA. For the electricity prices, no intraday or day-ahead prices are considered,
but daily closing prices of the next due futures contracts, in order to allow a more
precise analysis of the prices in consideration of changes in industrial expectations.</p>
        <p>For the oil price (in $/barrel), the prices of Brent crude oil were evaluated. The
corresponding contracts are traded on the ICE Futures, the largest futures exchange for
such futures in Europe. The price for coal (in $/t) is the currently traded contract month
on the ICE Futures. It is referenced to the coal index API#2(ARA), which is published
in Argus/McCloskey's Coal Price Index Report.</p>
        <p>To ensure that all data are in the same currency, the oil and coal rates are converted
into euros using the daily reference rates of the European Central Bank.</p>
        <p>The gas price (in €/MWh) used for the analysis is the natural gas month-ahead future
of the ICE Endex, the largest and most liquid gas exchange in Europe. The electricity
price (in €/MWh) is the Physical Electricity Index (Phelix) future price on the EEX for
the current month, shown as a Phelix baseload. This refers to the electricity base load
and serves as the reference price for electricity in Germany. In this paper, the German
electricity price is used because Germany is the largest economy in the EU and has the
highest share of the Europe-wide auction volume among the member states [11].</p>
        <p>The original series and the time series after the formation of the first differences,
therefore prefixed with "d_...", are tested for stationarity using the Augmented
DickeyFuller-Test. The results of the test show that none of the original time series exhibit the
property of stationarity. The first differences of the time series are all stationary, which
is why they were used for the test.</p>
        <p>The basis of VAR is that the individual time series in the system influence each
other. The Granger causality test is therefore used to test the relationships of the
individual variables to each other before the VAR model is created. The p-values of the test
show that the prices of fuels (gas, coal and Brent) have a significant influence on the
EUA price. No influences of the EUA price on the four energy variables are found. The
gas price also shows highly significant influence on the coal price. This justifies the
VAR modelling approach for this system with several time series to be forecasted.
Signif. codes: '***' 0.001; '**' 0.01; '*' 0.05; '.' 0.1; ' ' 1
In order to model the interactions between the EUA price and energy prices, a VAR
model is used for the econometric analysis in this study. In contrast to conventional
autoregressive models, this type of time series analysis model does not assume a
unidirectional relationship, i.e. that the target variable is influenced by the influencing
variables, but not vice versa. In the following VAR model, therefore, the feedback
relationships of all variables to be investigated are taken into account; formally expressed, all
variables are treated as endogenous:
 _
 _
 _
 _
 −1
 −1
 _
 _
 −2
 −2
 _ =  +   − ×  _  −1 +   − ×  _  −2 + ⋯ +  (1)
 _  _  −1  _  −2
(  _ ) (  _  −1 ) (  _  −2 )</p>
        <p>Where c is the column vector of the regression constants, β_(t-n) is the 5x5 matrices
of the regression coefficients with lag n and u is the residuals of the VAR model. Before
estimating the model, it has to be determined how many lags should be included. Here
it is important to weigh up the pros and cons, because too few lag values may leave
valuable information of the more distant values unnoticed or explanatory parameters
may be missing, while too many lag values may lead to over-specification of the model.
The model includes four lags, based on the Akaike information criterion.</p>
        <p>Impulse response functions (IRF) are derived from the VAR model, which indicate
how changes in one variable affect other variables. For this purpose, the variables under
investigation are subjected to an isolated shock (impulse) in the amount of one standard
deviation and its effects over time are determined. For the analysis of the IRF their plots
including the bootstrap confidence intervals are used. If the 95% confidence level at a
given time includes the zero line, there is no significant effect.
5</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Results and Discussion</title>
      <p>The impulse-response function from the EUA price by entering a gas standard
normal distribution leads to a decrease of the EUA price after one day. This is followed by
a stronger increase in the price. Cumulated, a positive influence can be determined.
This correlation between natural gas prices and EUAs could be due to the fact that there
is a high degree of substitutability between coal and gas in electricity production. Rising
prices in the gas sector therefore lead to a stronger demand for coal. Since a coal-fired
power plant for the generation of one kilowatt hour of electricity emits almost twice as
much carbon dioxide as a gas-fired power plant, this leads to a rising demand for CO2
emission allowances and thus to a price increase [14].</p>
      <p>The EUA price shows high volatility when the electricity price is stimulated.
Overall, an increase in the electricity price leads to a marginal increase in the EUA price.
This reaction can be explained by the fact that the companies need electricity for
production and a marginal change in the electricity price does not immediately lead to a
reaction on the part of the companies, which ultimately leaves the EUA price virtually
unaffected. In addition, the electricity price is influenced by production-related factors,
especially by the impact of coal and gas prices, so that these two energy prices already
absorb the influence of the electricity price on the EUA price [15].</p>
      <p>In the event of a shock in the coal price, the impulse response function shows an
overall positive correlation with the EUA price. In this way, an impulse in the coal price
after one day initially leads to a decline and from day three to a relatively strong
increase in EUA prices. This reaction can be explained by the substitutability of coal and
gas as described above. Thus, an increase in coal prices could ceteris paribus lead to a
fuel switch from coal-fired power plants to gas-fired power plants. As a result,
emissions will decrease and with it the demand for and price of CO2 emission allowances.
The reaction that the price of EUA rises despite this can be explained by the fact that
particularly energy-intensive industries are using this situation to expand their
production [10], which means that more electricity is produced by gas-fired power plants,
which in turn increases the price of EUAs.</p>
      <p>The impulse-response function for the EUAs price shows a negative correlation on
the first day in the event of a shock in crude oil, which, with a weaker positive reaction,
ultimately leads to a lower EUA price. This reaction can be due to a decreasing demand
for crude oil, which is why emissions are lower and therefore the decreasing demand
for EUAs leads to a lower price.</p>
      <p>The impulse response functions were described and explained in the previous
section. In the following, the results are assessed according to their significance, the
significance level being used as a measure. The regression parameters of the estimated
model with respect to d_EUA are presented in Table 5.
d_EUA.l1
d_EUA.l2
d_EUA.l3
d_EUA.l4
Residual standard error: 0.3447 on 1541 degrees of freedom
Multiple R squared: 0.03404,
F-statistic: 2.715 on 20 and 1541 DF, p-value: 6.466e-05</p>
      <p>A special focus in this presentation is on the differentiation between significant and
non-significant values. The coefficients for Brent (crude oil) show a significant value
on the first and third day. The significance level is below 1%. The absolute value of the
negative coefficient is marginally higher in comparison and provides a point of
reference for forecasting the future development of the EUA price. According to
Hammoudeh et al. [12], an increase in the price of crude oil leads to a sharp decline in CO2
emission allowances prices and this reaction reflects the present result of the vector
autoregression analysis carried out, according to which H1 of this study can also be
confirmed in phase III of the EU ETS.</p>
      <p>The coal price shows a positive influence on the EUA price on the third day with a
significance level of less than 1%. Consequently, the assumed negative influence of the
coal price in the context of H2 is not confirmed. As described above, the reasons for
this counterintuitive result could be the high degree of substitutability between coal and
gas.</p>
      <p>
        The reciprocity between the price of natural gas and the price of EUAs shows a
significantly positive influence on the fourth day, as assumed in H3, which has also
already been determined by Alberola et al [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ].
      </p>
      <p>For the influence of d_Electricity no significant coefficients are found. Therefore, in
the present model, in contrast to the existing literature (H4), no correlation between the
electricity price and the price of emission allowances can be established. This result can
be explained by the fact that the energy prices of coal and natural gas implicitly reflect
the influence of electricity anyway, since these are used for electricity generation,
among other things.
6</p>
    </sec>
    <sec id="sec-6">
      <title>Conclusion</title>
      <p>The results of this work show that the price of EUAs is significantly influenced by the
prices of fuels (Brent, coal, gas) in the third phase of the EU ETS. The extent of the
influence is less pronounced for the individual energy variables than was observed in
the previous phases. Furthermore, the influence of the electricity price on the EUA price
cannot be determined in the third phase. While the negative influence of Brent and the
positive influence of gas are confirmed, a positive influence on the EUA price is
observed for coal, contrary to the existing literature. This shows that the market influences
in phase III of the EU ETS have changed compared to the previous phases. One reason
for this may be that fossil fuels are gradually being pushed out of the energy market by
renewable energies. Electricity can also be produced with much lower emissions than
it was the case in the first phases of the EU ETS. The influence of the individual energy
sources on the EUA price has fallen accordingly over time. The present results could
therefore be an indication that the pricing of EUAs as an EU instrument is no longer
effective. The tendency for EUA prices to rise also indicates that this effect will
continue to increase in the coming years and that even lower-emission technologies will be
focused on the European area.</p>
      <p>Accordingly, this work offers the opportunity for further research to investigate the
forecasting capabilities of the EUA, taking into account other factors such as weather
or economic activity in the EU.
9. European Commision, https://ec.europa.eu/clima/policies/ets_en, last accessed 2019/12/09.
10. Federal Ministry for Economic Affairs and Energy,
https://www.bmwi.de/Redaktion/DE/Artikel/Industrie/energieintensive-industrien.html,
last accessed 2019/12/01.
11. German Emissions Trading Authority (DEHSt) at the German Environment Agency:
Factsheet,
https://www.dehst.de/SharedDocs/downloads/DE/publikationen/Factsheet_EH2013-2020.pdf;jsessionid=8C6131F797EC1868F2F95EB232AD0905.2_cid331?__blob=
publicationFile&amp;v=10, last accessed 2020/03/08.
12. Hammoudeh, S., Nguyen, D. K., Sousa, R. M.: Energy prices and CO2 emission allowance
prices: A quantile regression approach. Energy Policy 70, 201-206 (2014).
13. Hintermann, B.: Allowance price drivers in the first phase of the EU ETS. Journal of
Environmental Economics and Management 59 (1), 43–56 (2010).
14. Juhrich K.: CO2-Emissionsfaktoren für fossile Brennstoffe. Climate Change 27, 27-40
(2016).
15. Löschel A.: Die Zukunft der Kohle in der Stromerzeugung in Deutschland: Eine
umweltökonomische Betrachtung der öffentlichen Diskussion. Energiepolitik 1, 21 (2009).</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Aatola</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ollikainen</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Toppinen</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          :
          <article-title>Price determination in the EU ETS market: Theory and econometric analysis with market fundamentals</article-title>
          .
          <source>Energy economics 36</source>
          ,
          <fpage>380</fpage>
          -
          <lpage>395</lpage>
          (
          <year>2013</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>Alberola</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chevallier</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chèze</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          :
          <article-title>Price drivers and structural breaks in European carbon prices 2005-2007</article-title>
          .
          <source>Energy Policy</source>
          <volume>36</volume>
          ,
          <fpage>787</fpage>
          -
          <lpage>797</lpage>
          (
          <year>2008</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <surname>Benz</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Trück</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          :
          <article-title>Modeling the price dynamics of CO2 emission allowances</article-title>
          ,
          <source>Energy Economics 31</source>
          ,
          <fpage>4</fpage>
          -
          <lpage>15</lpage>
          (
          <year>2009</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Bredin</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Muckley</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          :
          <article-title>An emerging equilibrium in the EU emissions trading scheme</article-title>
          .
          <source>Energy Economics</source>
          <volume>33</volume>
          ,
          <fpage>353</fpage>
          -
          <lpage>362</lpage>
          (
          <year>2011</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <surname>Bunn</surname>
            ,
            <given-names>D. W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Fezzi</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          :
          <article-title>A vector error correction model of the interactions among gas, electricity and carbon prices: an application to the cases of Germany and the United Kingdom</article-title>
          .
          <article-title>Markets for carbon and power pricing in Europe: theoretical issues and empirical analyses</article-title>
          ,
          <fpage>145</fpage>
          -
          <lpage>159</lpage>
          (
          <year>2008</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <surname>Chevallier</surname>
            ,
            <given-names>J.:</given-names>
          </string-name>
          <article-title>A model of carbon price interactions with macroeconomic and energy dynamics</article-title>
          .
          <source>Energy Economics</source>
          <volume>33</volume>
          ,
          <fpage>1295</fpage>
          -
          <lpage>1312</lpage>
          (
          <year>2011</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Christiansen</surname>
            ,
            <given-names>A.C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Arvanitakis</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Tangen</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          :
          <article-title>Price determinants in the EU emissions trading scheme</article-title>
          .
          <source>Climate policy 5 (1)</source>
          ,
          <fpage>15</fpage>
          -
          <lpage>30</lpage>
          (
          <year>2005</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <surname>Creti</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jouvet</surname>
            ,
            <given-names>P.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Mignon</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          :
          <article-title>Carbon price drivers: Phase I versus Phase II equilibrium</article-title>
          .
          <source>Energy economics 34 (1)</source>
          ,
          <fpage>327</fpage>
          -
          <lpage>334</lpage>
          (
          <year>2012</year>
          ).
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>