Scheduling hydro, geothermal and wind resources for electricity spot market trading

The Icelandic power system, is currently based entirely on renewable energy from hydro and geothermal gen-erators. In addition, wind resources are being developed. In the past the systems has served local demands of two types: (a) Variable General Demand (VGD) and (b) the dominating and constant Energy Intensive Industry Demand (EIID). The VGD load is variable by the hour but the EIID is constant. Both loads must be served at all times to satisfy bilateral contracts in the absence of a local electricity spot market. In this paper, we examine the possibility of trading in the United Kingdom (U.K.) spot market through a submarine HVDC interconnector (IC). The benefits are estimated using a two stage scheduling model, HYDW2 (HYDro and Wind scheduling model 2) with two stages: (1) weekly and (2) hourly. The HYDW2 uses Linear Programming (LP). It is applied to a specific test case based on the Icelandic system, but with new hydro and wind generators. The key interaction of wind with hydro reservoirs and the spot market is of particular interest. The input data include historical spot prices, local loads, primary energy inflow, IC constraints and other system attributes. The potential benefits include less spilled water and idle hydro capacity, higher income, resource rent and improved supply security and the possible significant reduction in Greenhouse gas emissions.