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ESC calculates average new residential gas use in Victoria, accepts 2006 baseline figures for each year of third regulatory period

Posted by gmarkets on 3 September, 2007

While statistics were difficult to verify, up to 80 per cent of new houses might have gas-boosted solar hot water and an overall average new residential use of around 47 GJ was an acceptable working figure, said the Essential Services Commission (ESC) in its Draft Decision on the Gas Access Arrangement Review 2008-2012. Gas Hot Water Usage: “The distributors’ demand forecasts assume that for new houses there will be an initial penetration of 20 per cent of solar hot water by 2006 increasing to 40 per cent in 2010,” the document said. “Empirical evidence on the penetration of gas boosted solar hot water units is mixed. Referring to work undertaken by BIS Shrapnel in 2006, George Wilkenfeld and Associates noted in 2007 that even the same survey organization using the same method, comes up with significantly different findings.”

Survey suggests higher proportion of gas boosted solar hot water: Envestra had provided information which suggested that in 2006 61 per cent of houses were being built with gas boosted solar hot water. However, the Commission’s informal survey suggested that this proportion could now be closer to 80 per cent.

Plumbing regulations: “The Commission considers that the distributors estimate of changes in gas use due to changes in plumbing regulations are reasonable,” the Draft Decision said.

MEPS: “As noted above, the Commission does not consider it is reasonable to assume reductions due to minimum energy performance standards for gas appliances,” the document said.

Likely average use calculated on “reasonable basis”: “Given the lack of empirical data available regarding the impact of the five star building requirements and other factors it is necessary to determine the best estimate of likely average use by new customers arrived at on a reasonable basis,” the ESC found. “The Commission agrees with the distributors that average use by new residential customers is likely to be less than that for existing customers. This will occur as a result of new plumbing regulations and improvements to building shell design. The Commission also considers that the distributors may have underestimated the reductions in usage resulting from solar boosted hot water. However, the Commission’s view is that:

• the strong trend towards gas central heating is likely to promote usage of gas; and

• it is not reasonable to assume reductions in usage due to MEPS.”

Approximate values for major uses of gas: “Even allowing for the impact of reduced usage in multi unit premises,” the ESC said, “the average usage figures provided by the distributors for 2007 of between 33 and 39 GJ are not reasonable given that:

• the vast majority of new dwellings being connected to the gas network in Victoria will have gas central heating, which according to the distributors’ figures currently uses an average of 56 GJ per annum for a three star appliance;

• gas boosted solar hot water in a new dwelling will use around 8GJ per annum; and

• average gas use for cooking is 3GJ per annum.”

Conservative calculation of average usage: “Drawing on the distributors figures data contained in Wilkenfeld and the Commission’s own analysis,”, the ESC said, “a more reasonable forecast regarding average usage might be developed using the following relatively conservative assumptions:

• 85 per cent of new dwellings have 3 star ducted gas heating;

• 10 per cent of new dwellings have 4 star non-ducted gas heating;

• 5 per cent of new dwellings have no gas heating;

• 75 per cent of new dwellings have gas boosted solar hot water;

• 20 per cent of new dwellings have gas hot water;

• 5 per cent have electric hot water;

• 77 per cent of new dwellings have a gas cooktop and 40 per cent have a gas oven.

Based on the above assumptions, and assuming that a 3 star central gas heater will use 35 per cent less energy in a new five star building home than an existing home, average new residential use will be around 47 GJ.”

Distributors 2006 baseline figures adopted: “This figure is broadly consistent with the baseline 2006 average use assumption adopted by the distributors. The Commission therefore considers it is reasonable to adopt the 2006 baseline figures proposed by the distributors, to apply for each year of the third regulatory period.”

Reference: Gas Access Arrangement Review 2008-2012, Essential Services Commission, Draft Decision, Executive Summary, 28 August 2007.

Erisk Net, 2/9/2007


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