An inland province uses electricity at a fairly constant rate during the night. On cold winter evenings, demand increases rapidly.

Surveys have found suitable hot rocks beneath part of the province, and natural gas is also available. The province is choosing between building a geothermal power station and building a gas power station.

Compare the two proposed power stations as sources of electricity for the province. Include their reliability, their environmental effects and how effectively their output can respond to the daily pattern of demand.