Option Electricity Market Design
Option Electricity Market Design
the development of option market in electricity equivalent option contract. Thus, can predict
trading. Pug et al., 2009, considers the pricing of replacement of gaming in existing UI mechanism and
electricity swing options that hedge the electricity reflect explicitly the manner of price hedging. The
price risk and also partly the risks in the option outcomes to some extent can give answers to the
owners load pattern. Also Hjalmarsson. E., 2003 following issues:
tries to use Black and Scholes formulation for a) Is the electricity market functioning of India is
electricity option pricing. Given that many of the compatible with option market.
existing options on electricity contracts are, in fact, b) If the options were introduced, how would present
options on electricity forwards rather than on the trades appear in value terms.
actual spot price, this involves modelling both c) How to measure the hedging cost of existing UI
electricity spot and forward prices (Hjalmarsson. E., and proposed option contracts.
2003). In (Rashidinejad, et al., 2000) the option price
of spinning reserve is studied using the Black and Prevailing UI Mechanism
Scholes formula. Selling electricity through a forward India has opened up a competitive power market in
contract at a fixed price to hedge against price spikes 2003 after the enactment of Electricity Act. With that
in pool market is discussed in (Conejo, et al., 2008). the sector has experienced participation of private
A technique for price-quantity hedging through players, mainly in generation and distribution. Aiming
power options in Colombian spot market is framed in at proper scheduling and real time operations, power
(Gabriel, et al., 2011). Additionally some relevant exchanges are created. Result to this, now there are
literatures that study real options in electricity are three major markets exist covering generation,
given in (Denton, et al., 2003). However, no study distribution, and retail trading: 1) Day-ahead spot
about a day a-head option model has been proposed market which determines the efficient dispatch of
in the literature. This is essential for electricity generating sources considering the offers submitted by
market like India, to avoid gaming with the existing loads a day ahead of actual dispatch: 2) Bilateral
unscheduled interchange mechanism. Also the studies market with a long trajectory covering contracts of
mentioned above consider transaction between more than a year: 3) Frequency actuated power
demand and supply and none of those were concern transaction through UI for real time balancing market.
about the profit profile of generation companies.
Since there is no reliable option pricing methodology ABT provides a frequency based incentives/penalties
available in literature, the most dependable way to to beneficiaries (e.g., Gencos). It has three part tariff
analyze option pricing on electricity contracts is to calculation; they are a) capacity charges: payment of
estimate models from the existing underlying assets fixed charge of the plant, b) energy charges: payment
and, from these, derive the corresponding option of fuel cost for schedule generation and c) UI
prices. charges: payment for deviation from schedule at a
rate dependent on system frequency. The UI charge is
The frequency control functionality of the UI for supply and consumption of energy in variation
mechanism is explained in (Parida, et al., 2009). Paper from the pre-committed daily schedule. This charge
Channa, et al., 2010, describes implementation of UI varies inversely with the system frequency prevailing
charges in ABT regime to co-ordinate the optimum at the time of supply/consumption. All these three
day a-head declaration. Soonee, et al., 2006, explains components are calculated in 15 min time block for
techno-economical and socio-political burdens for total 96 blocks of a day. UI charges are stochastic in
implementation of various real-time adjustments to nature as it varies with the change in frequency as
price real time demand. A work on stochastic model shown in fig 1. The price of power from UI follows
for day a-head declaration of power in ABT regime the ABT rate which is associated with the frequency
was published in (Vaitheeswaran, et al., 2006). The of the grid.
effect of scarcity, spot volatility and skewness are
8
significant in Indian electricity market, owing to the
U I rates in Rs ./K W h
managed under regulatory supervision. This sustained basis in a civilized and competitive market.
provision is to generate extra in real time scenario to The whole idea of relying on administered penalties
maintain generation and load balance. The real time is inefficient, subject to disputes and subject to
adjustment of power reference set is carried out by continual pressure to seek modifications and
means of a frequency linked unscheduled interchange exceptions. Non-compliance can also be justified by
price mechanism (Rules and regulations, available claiming an operating problem, etc. Therefore the
online). The UI mechanism is quite similar to the concept of option market design is being proposed in
price based real time balancing mechanism. Under UI this work. This could help in straightening up the
mechanism, all the real time deviations are settled prevailing spot price signal in India.
according to a predefine price curve. The UI price is
monotonically decreasing function of system UI As An Option Contract: Model
frequency. That is, higher the frequency lower is the For a Genco in spot market, the extra power
price. This intern provides incentive to the generator generated would be such that it will maximize the
to increase power generation when the system profit in the prevailing option price. With UI
frequency is lower and for decreasing power mechanism being commercially gambled, the idea of
injections when the frequency is rising. The ability to making UI as an option service can be modeled with
make load and generating entities to participate in two type of market; balancing energy market (UI
real time balancing is one of the key features of the mechanism) and reserve capacity market (Option
UI mechanism. However the purpose of UI contracts). The aim here is to analyze alternative
mechanism is to tighten the frequency band of the design options for these balancing markets. A
system to increase reliability. Recent studies shows theoretical model can be developed linking the above
involvement of gaming through over injection by two markets.
generating stations in excess of 105% generators
declared capacity with an intention to make profit Nowadays there is no future market for electricity in
under UI mechanism. This 5% increment from India. However, if for analytical purposes option
declared capacity depends on generator droop prices must be evaluated, then some future prices or
characteristics. The production level adjustment some kind of adjustment on the spot prices should be
through droop control is known as regulation service. estimated. The method applied in this paper was the
The regulation services are procured through energy- introduction of the adjustment of spot prices at the
reserve co-optimization in the day-ahead or real time beginning. As the option market aims at replacing the
market (Wu T., et al., 2004) (Zheng T., et al., 2006). UI mechanism, so design of a day-ahead option is
proposed here. Fig.1 gives a timeline diagram for the
According to the recent findings on Indian power proposed market model.
market, the UI mechanism faces lack of liquidity
affecting the reliability of the system both from The analysis considers a contractual arrangement
technical and economic aspects. No consideration is between a seller and a buyer for trading one unit of
made in the UI pricing for system congestion i.e., electrical energy at some future time. The same unit
because of excess demand in real time. Therefore, in of energy is being traded both in option and spot
real time there can be overloading in the lines. This market. As per the marginal cost theory the Gencos
can be one possible reason for the recent black out in will get more profit if P > UI . Here UI refers to
India. To avoid such a situation, the UI mechanism
the UI price. It would be beneficial if the generator
should be complemented with some other financial
sells from the available options. Figure 3 below
instruments like options.
explains the theoretical model with choices of both
option and UI
Also Cramton P., et al, 1998, in A Review of ISO
New Englands Proposed Market Rules say,
Reliance on penalties is highly inefficient and
problematic in its workings and is unworkable on a
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Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):215- 222 (ISSN: 2141-7016)
UI > C
0, UI C
C C
UI < P
0, P UI
P P
( UI C ) . Similarly, when UI charges are turned From the ACP and ACV data collected from Indian
Energy Exchange (IEX) for the northern region, the
out to be low, the seller exercises the put option and correlation coefficient is estimated to be 0.37 and
receives a profit of ( P UI ) . Here the author aims 0.71 in the year of 2013 and 2014 respectively. This
shows a steeply rising value of both load and
only Gencos prospective of participating in option generation dependency on spot prices. Therefore the
market with objective of maximizing its profit. author aims to develop an economically convenient
model for Gencos to maximize their pay off in the
To evaluate how a put option is used to hedge against electricity spot market. In the following a detailed
price risk faced by a power producer, consider that procedure is presented.
generator unit does not fail. Also assume that the
realization of high/low pool prices prior to the option Calculation of Option Strike Price
exercising time will lead to high/low pool prices Under Indian electricity market regime, the day a-
during the delivery time. In that case, if electricity head market is cleared at market clearing price
(MCP). Any deviation of real time market from day
t
RP = {S (t ) QS (t ) + UI (t ) QUI (t )} (1)
ahead is awarded through UI mechanism. So the
revenue of a generating unit in real time market can
0
be given by the following equation
prices become high before the expiration time,
producer decides not to exercise option so as to sell where, QUI ( t ) is the unbalanced real time amount in
its production in pool market with higher price. On MWh. With the aim to develop a stochastic model to
the other side, falling pool prices between the maximize Gencos revenue in the option contract
purchase and the exercising time of the option would frame work, the UI term has to be subsided. Instead,
encourage the power producer to exercise the put assume a Genco, signs a contract of quantity QP and
option to sell electricity at a pre-defined strike price. awarded price P in the spot market. Each option
In this way, the put option allows the power producer contract comes with a premium price. The option
to hedge the risk corresponding to high volatility of premium value ( 0 ) is kept constant i.e., Rs.1.5 per
prices.
option unit. Any deviation of real time market from
the day a-head market is awarded in the option
The following simplifying assumptions are considered
market at strike price. Therefore, the revenue of a
to formulate the stochastic model of option pricing.
Gencos unit is
a) The generating units owned by the power t
producer are dispatchable thermal units, whose TRP = {S (t) QS (t) +P(t) ( QG(t) QS (t))} 0 ( QG(t) QS (t)) (2)
cost is modeled by a piecewise linear function. 0
11
10
Option Allocation Problem With Risk Mitigation
With option contract, the uncertain spot prices in real 9
time can be considered as stochastic time 8
Numerical Test Results The Genco will have the choice of selling
Here, the application of the methodology described in imbalanced power, either in option or through UI,
the prior section is performed with the available whichever have higher value.
information of the Indian power market from January
2014 to October 2014. Block wise spot prices are
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Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):215- 222 (ISSN: 2141-7016)
E xpected payoff
obtained strike prices are presented in Figure 5 2
below.
1
800
UI
700 Option
0
Spot Price(Paisa/kWh)
600
500 -1
200 250 300 350 400 450 500 550
400
Price(Paise/kWh)
300
Figure 8. Expected payoff functions of Option
200
100
0 10 20 30 40 50 60 70 80 90 100
Figure 7 illustrates the expected payoff function for
Time Index (In 15min Block) UI as a real time market pricing. Similar way Figure
Figure 5. Option (strike price) and UI price. 8 illustrates the expected payoff for option prices.
Considering 1000 scenarios of Monte Carlo
It can be seen that, with option prices a hedging simulations the profit distributions are plotted for
profiles for peak and off peak hours are being before and after price hedging cases. It can be
incurred. Thus helping in supressing effects of observed from Figure 9(a) and 9(b) that, for Gencos;
market gaming. It can be observe from Figure 6 the profits mean slightly rises when following the
below that, Gencos profit are reducing with options price hedging strategy thus satisfying the objective
as compared to UI, this is because that with taken.
-13
increasing UI price, the possibility to exercise the put x 10
2.5
option will be relatively large, which makes the put
option contract price act more like a real time market 2
Probability Density
Genco will bid with the highest available price bid. 0.5
So Profit will have an increasing trend as shown
below. 0
-0.5 0 0.5 1 1.5 2 2.5
7
x 10 Profit(Crores) 7
3 x 10
Only Option
Only UI
Figure 9(a). Profit distribution before hedging
2.5 -14
Both UI and Option x 10
5
2
Expected Profit (Crores)
4
P ro b ab ility D en sity
1.5
1
3
0.5 2
0 1
-0.5
0 10 20 30 40 50 60 70 80 90
0
Time Index (In 15min Block)
-1 -0.5 0 0.5 1 1.5 2 2.5 3
Profit(Crores) 7
Figure 6. Comparison of profit profiles of Genco. x 10
x 10
7 Figure 9(b). Profit distribution after hedging.
1.5
Here, taking the assumption that total generation (P)
1 = total load (Q), the expected values of profit are not
E x p e c te d p a y o f f
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Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(7):215- 222 (ISSN: 2141-7016)
is solved. Figure 10 illustrates the amount with some extent could answer the issues discussed in
different risk factor and contract prices. It can be seen section 2 of the paper.
that, to reduce UI price risk, the Genco will allocate
more capacity in option market with larger risk One limitation of this approach is that, it doesnt
factor. consider LSEs portfolio thereby lacking market
1300 liquidity. To achieve a new electricity derivative
r =0.5 market in India, it is necessary to consider LSEs
1200 portfolios and analyse the practical aspects of
O ption Q uantity (M W )
222