Tasmania needs to look at efficiency to resolve electricity crisis

The announcement this past week by the Basslink operator that repairs to the cable may not be completed until early June, by which time cold weather will have well and truly arrived, show that the risks to Tasmania’s energy supply continue to mount.

Figure 5 shows the dramatic change in the supply mix since the Basslink failure, with gas generation substituting for imports from Victoria during the past three months, together with a small contribution from diesel generation during March.

Negative flows on Basslink during May, June, July and August last year are net exports of hydro electricity from Tasmania to Victoria.

It is also interesting to see that total supply, and therefore demand, during January and February this year was almost the same as in January and February 2015. However, supply and demand in March were significantly lower than in March 2015.

The difference may in part be the result of unusually mild weather during March. According to the Bureau of Meteorology, the average temperature in Tasmania during March was the sixth highest on record and the average daily minimum temperature was the fourth highest on record.

Another large part of the difference is presumably the result of agreed reductions in supply to major industrial users, which account for nearly 60% of total Tasmanian electricity consumption.

The large user share of consumption is much higher in Tasmania than in any other Australian state, presenting both challenges and opportunities for managing the supply crisis and its aftermath.

The challenge can be clearly seen in Figure 6. This figure has been created by allocating the total consumption by large industrial uses, as reported by AEMO, uniformly to every day in the year.

The resultant month by month estimate of major industrial consumption is then subtracted from total monthly consumption, also taken from AEMO data, as compiled in the CEDEX data system. The subtraction gives month by month estimates of consumption by general business and residential consumers.

The dramatic increase in monthly consumption by general consumers as colder weather comes in May and June is clear to see. While there has been an earlier‐than‐ expected return to production of a 57MW gas unit at Bell Bay, the balance of this expected growth in demand will need to be met by the 200MW of emergency diesel generator sets, together will any inflows into hydro system and wind.