Figures 7 and 8 show the total combined annual revenue received from all consumers (residential and business) by both distribution network business in each state (which account for between 70% and 80% of the total revenue) and transmission businesses.

It can be seen that, firstly, the rate of increase is much the same as the increase in revenue received from residential consumers alone and, secondly, that revenue of the businesses in NSW and Queensland is considerably higher than the revenue of the businesses in other states, and also increased much faster, particularly over the years from 2010 and 2013.

Revenue received by network businesses is used to cover their operating costs and also to service the capital which they invest. Figure 9 shows total key trend data since 2006 for the four NSW network businesses – Transgrid (transmission), and Ausgrid, Endeavour Energy and Essential Energy (distribution).

Revenue and expenditure are expressed in real dollars, whereas the data in Figures 7 and 8 are in nominal dollars, which is why growth in expenditure and revenue appears slightly slower in Figure 9.

The Figure shows that annual operating expenditure increased by a factor of about 1.4 between 2006 and 2012, while annual capital expenditure more than doubled over the same period.

By contrast, the quantity of electricity supplied to consumers over the whole year, measured in energy units (TWh), increased by less than 2% up to 2011, and since then has fallen away to be over 9% below the 2006 level.

The annual peak trading interval (30 minute) demand, measured in power units (MW), increased faster up to 2011, but since then has also fallen away.

In some years, including, most recently 2012 and 2015, peak demand in the NSW region of the NEM is higher in winter than in summer.

However, peak summer demand is usually more challenging for system operation, because the efficiency of both generation (including both thermal and renewable generation other than hydro) and transmission is lower at high ambient temperatures. For these reasons, forecast peak demand is a key driver of capital expenditure to increase supply capacity.