1. Fuel Choice Model The Total Resource Cost (TRC) Perspective Michael Schilmoeller 10/27/2011 (revised)

2. Summary-TRC Perspective Over 20 years – 340 MWa decline in power use due to net conversion to gas – 13.1 x 10 12 BTUs per year increase in direct gas use, but about 7 x 10 12 BTUs per year decrease net of power generation (power generation use declines 20 x 10 12 BTUs per year ) – 2,593,900 existing households Annually (just divide by 20) – 17 MWa decline in power use due to net conversion to gas – 657 x 10 9 BTUs per year increase in direct gas use, but about 350 x 10 9 BTUs per year decrease net of power generation – 129,695 existing households

3. Similarity of Appliance Performance Example for Gas Tank (2) in Water Heating Choices Slide

4. Water Heating Choices 129,693 households per year 31,202 households/yr 13,379 households/yr 15,010 households/yr 6,430 change to electricity -101.4 BTUs 10^9/yr 64,356 households/yr 21,197 change to gas 364.5 BTUs 10^9/yr 5,745 households/yr 5,745 change to gas 99.7 BTUs 10^9/yr T T T T

5. Similarity of Appliance Performance Example for HPWH (1) in Water Heating Choices Slide

6. Space Heating Choices 129,693 households per year 15,343 households/yr 4,111 households/yr 19,275 households/yr 72,919 households/yr 799 change to gas 31.6 BTUs 10^9/yr 4,793 households/yr 67 households/yr 6,019 households/yr 491 households/yr 6,177 households/yr 6,136 change to gas 247.2 BTUs 10^9/yr 499 households/yr 499 change to gas 15.7 BTUs 10^9/yr T T T T T T T T T

7. Summary Gas and electric appliances for space and water heating have become competitive both in terms of efficiency and cost – Where the model selects a particular appliance, there are typically appliances using the alternative fuel with similar performance – Given the precision of our calculations, there is no clear winner The total number of space heating conversions is small (7,434 annually or less than 6 percent of households) and are to gas from electricity. These households either – Use or will use gas for water heating anyway, or – Do not value the air conditioning that heat pumps can provide and require only a service extension for natural gas (not a main extension) The total number of water heating conversions to gas from electricity is significant (26,942 annually or about 21 percent) – These households either already have natural gas for space heating or will add it to convert their space heating The total number of water heating conversions to electricity from gas is small (6,430 annually or less than 6 percent) – These households have water heaters of greater than 55 gallon capacity and therefore must add a more efficient appliance. They select heat pump water heaters over gas water heat technology. – Again, the competition between gas and electric appliances is close. If condensing gas were chosen in lieu of a heat pump water heater, the effect over 20 years would be to lower the electric savings to 240 MWa from 340 MWa. From a regional planning perspective, this is small.