From Physical Data to Bid Offers

This document describes the process of transforming physical data from asset owners into bid offers for various unit types, including thermal, renewable, and hydro units. Bid offers are calculated using predefined formulas that incorporate operational parameters, risk factors, and specific bidding approaches.

Asset Owner attributes

  • $I$: Set of assets owners
  • $BG(i)$: Set of Bidding Groups of asset owner $i$
  • $J^T(b, n)$: Set of thermal units of bidding group $b$ and network node $n$.
  • $J^H(b, n)$: Set of hydro units of bidding group $b$ and network node $n$.
  • $J^R(b, n)$: Set of renewable units of bidding group $b$ and network node $n$.
  • $J^{DE}(b, n)$: Set of elastic demand units of bidding group $b$ and network node $n$.
  • $F(b)$ Set of risk factors for bidding group $b$.
  • $m_f$: Risk factor.
  • $s_f$: proportion of the risk factor $r$ in the bidding group $b$.
  • $B(t)$: Set of subperiods in period $t$.

Parameters

  • $d(\tau)$: Duration in hours of subperiod $\tau$.

Thermal Units

The bid offers for thermal units are based on their maximum generation and operational costs. The maximum generation $\overline{G}^T_j$ and om cost $\overline{C}^T_j$ are converted to bid offers by using the following formula:

\[\begin{align} Q_{i, n, \tau, k}(\omega) &= s_f \cdot \overline{G}^T_j \cdot d(\tau) &\quad \forall k = (j - 1) \cdot |F(b)| + f, f \in F(b), j \in J^T(b, n) \\ P_{i, n, \tau, k}(\omega) &= (1 + m_f) \cdot \overline{C}^T_j &\quad \forall k = (j - 1) \cdot |F(b)| + f, f \in F(b), j \in J^T(b, n) \end{align}\]

Where:

  • $Q_{i, n, \tau, k}(\omega)$ represents the bid offer in segment $k$ for energy quantity in period $\tau$, calculated by multiplying the unit’s maximum generation $\overline{G}^T_j$, the duration of the subperiod $d(\tau)$, and the proportion of the risk factor $s_f$.
  • $P_{i, n, \tau, k}(\omega)$ represents the bid offer in segment $k$ for price, calculated by applying a risk factor $m_f$ to the operational cost $\overline{C}^T_j$.

The bid offers are calculated for each thermal unit $j$ in bidding group $b$ and network node $n$ and bid segment $k$. Each segment represents a combination of thermal unit and risk factor, so the number of segments is the product of the number of thermal units and the number of risk factors in the bidding group.

Note: Other thermal unit attributes are not considered when forming these bid offers.

Renewable Units

For renewable units, the conversion incorporates the maximum generation $G^R_j$, the realized generation $G^R_{j, \tau}(\omega)$ and om cost $\overline{C}^R_j$ are converted to bid offers by using the following formula:

\[\begin{align} Q_{i, n, \tau, k}(\omega) &= s_f \cdot G^R_{j, \tau}(\omega)\cdot G^R_j \cdot d(\tau) &\quad \forall k = (j - 1) \cdot |F(b)| + f, f \in F(b), j \in J^R(b, n) \\ P_{i, n, \tau, k}(\omega) &= (1 + m_f) \cdot \overline{C}^R_j &\quad \forall k = (j - 1) \cdot |F(b)| + f, f \in F(b), j \in J^R(b, n) \end{align}\]

The renewable unit bid offers follows the same structure as thermal units, with the exception that the energy quantity is calculated using the realized generation $G^R_{j, \tau}(\omega)$ instead of the maximum generation.

Demand Units

Demand unit bid offers are derived from the elastic demand $d^E_{j, \tau}$ and the demand price $P_{j, \tau}(\omega)$ are converted into bids by using the following formula:

\[\begin{align} Q_{i, n, \tau, k}(\omega) &= s_f \cdot d^E_{j, \tau}(\omega) &\quad \forall k = (j - 1) \cdot |F(b)| + f, f \in F(b), j \in J^{DE}(b, n) \\ P_{i, n, \tau, k}(\omega) &= (1 + m_f) \cdot P_{j, \tau}(\omega) &\quad \forall k = (j - 1) \cdot |F(b)| + f, f \in F(b), j \in J^{DE}(b, n) \end{align}\]

Hydro Units

For hydro units that are not associated to virtual reservoirs, the bid offers are derived from a Minimum Cost Run, where the generation output $g^H_{j, \tau}$ and opportunity cost $\pi^H_{j, \tau}$ are converted into bids. The conversion is performed using the following formulas:

\[\begin{align} Q_{j, n, \tau, k}(\omega) &= s_f \cdot g^H_{j, \tau}(\omega) &\quad \forall k = (j - 1) \cdot |F(b)| + f, f \in F(b), j \in J^H(b, n) \\ P_{j, n, \tau, k}(\omega) &= (1 + m_f) \cdot \pi^H_{j, \tau} &\quad \forall k = (j - 1) \cdot |F(b)| + f, f \in F(b), j \in J^H(b, n) \end{align}\]

In the Independent Bids approach, it has the same structure as thermal and renewable units, with the exception that the energy quantity is calculated using the generation output $g^H_{j, \tau}(\omega)$ instead of the maximum generation. This is just a simplification of the bid offer calculation.