Natural gas price is the natural gas futures price
at the National Equilibrium Point (NBP) in the UK.
The prices of various trading markets in the EU are
correlated and interactive. Among them, NBP is the
most representative market, which can be used to
represent the natural gas cost of energy input in
Europe.
The coal price is based on the spot price of coal
for the next month's delivery in
Antwerp/Rotterdam/Amstor (ARA) at various
European ports. The coal trading price index is
published weekly, representing the cost of imported
coal in northwest Europe.
As the primary source of carbon emissions and
the main entity to purchase carbon emission quotas,
power enterprises will greatly impact the carbon
market. However, the power price factor is not
correlated with carbon emissions as other energy
variables, and the power conversion variable can be
given by Equation (1). P is the cost of carbon
emissions of the balance. 𝑃
and 𝑃
are the
corresponding price of coal and natural gas at the
corresponding time point.𝑀
𝑎𝑛𝑑 𝑀
are the carbon
emissions for each 10
units of electricity
generated by two different power generation
methods.𝐾
and 𝐾
are conversion variables, which
are related to the type of settlement currency, unit
commodity quantity, and power generation
efficiency. The P of the equilibrium point is the target
power conversion.
CG
CG
CG
PP
PM PM
kk
×+ =×+
(1)
2.2.2 Economic Factors
Economic factors will lead to the fluctuation of
carbon futures prices. Carbon emission permits are
the production costs of enterprises with high energy
consumption. The rise and fall of the price of carbon
emission permits may affect a particular industry, and
the prosperity degree of the industry will also affect
the carbon price. For example, the stock market
index mainly reflects the profit expectation of
enterprises and investors' optimism about the
prospect of economic development, which will affect
the production of enterprises and thus affect carbon
emissions. However, different markets have different
paths and degrees of influence.
The economic factors used in this paper include
the CRB index price that reflects the bulk commodity
market. The CRB index includes the price fluctuation
of the core commodity, which is widely used to
observe and analyze the price fluctuation of the
commodity market and the macro-economic
fluctuation and reveal the future trend of the macro-
economy to a certain extent.
The Stoxx 50 Index, which reflects the stock
market, is a weighted average index composed of 50
super blue-chip stocks listed in the capital markets of
12 countries such as France and Germany, which are
members of the European Union. The financial
securities circles regard the index as an indicator of
the overall situation of the share prices of large listed
companies in the eurozone.
The Traxx Europe International Credit
Derivatives Index, which reflects the bond market,
comprises one hundred and twenty-five (125) liquid
European entities with investment-grade credit
ratings. It can be regarded as a benchmark index for
the continental bond market, and investors can use it
to obtain the latest developments in the European
bond market.
3 EUA FORECAST BASED ON
ARIMA-GARCH
𝐴𝑅𝐼𝑀𝐴
𝑝, 𝑑, 𝑞
(summation autoregressive moving
average model) is a method with high short-term
prediction accuracy. It is composed of difference
order, autoregressive model, and moving average
model. The non-stationary time series of the ARIMA
model is transformed into the ARMA model by d-
order difference. The form of the model is:
(2)
),0(~
2
σε
WN
t
(3)
Meanwhile, the data stationarity should be tested
before using the 𝑨𝑹𝑰𝑴𝑨(𝒑, 𝒅, 𝒒) model.
The generalized autoregressive conditional
heteroscedasticity model (GARCH) is mainly aimed
at autocorrelation, which can effectively fit the
current conditional variance with long-term
correlation. 𝑮𝑨𝑹𝑪𝑯(𝒑, 𝒒) model satisfies:
(4)
(5)
(6)
This paper uses the EU carbon futures settlement
price (EUA) to establish an ARIMA-GARCH model
and uses this model to forecast the EUA price in the
next three months.
tt
d
BxB
ε
)()( Θ=∇Φ
ttt
u