Negotiating Bilateral Contracts in Electricity Markets

In mixed pool/bilateral electricity markets, participants can sign forward bilateral contracts several months in advance of its delivery. In addition, generators may sell to and loads may buy from the pool at the spot price through the day- ahead or balancing markets. Forward bilateral contracts have the advantage of price predictability in comparison with the uncertain spot price. However, the risk is that such a contract commits the partners to a price that may be disadvantageous compared to the spot price. Here, we propose a systematic negotiation scheme through which a generator and load can reach a mutually beneficial and risk tolerable forward bilateral contract, either physical or financial. Under this approach, the generator and load respond rationally to a stream of bilateral bids/counter-bids and offers/counter-offers considering their respective benefits while accounting for the risks incurred by the prediction uncertainty in the pool spot price and other market parameters over the length of the contract. Each negotiating party can choose its own definition of risk which can be influenced by regret, value-at-risk or dispersion from the mean. Numerical tests show that this flexible negotiating approach can be readily put into practice.