Implications of electrified residential space heating in California

In order to meet ambitious emission reduction goals in California, greenhouse gas emissions from direct combustion of fossil fuels for residential space and water heating will need to be largely eliminated. If those emission reductions come from fuel switching (natural gas to electricity) then the electricity grid needs to be prepared for the additional load. This paper presents a new method for estimating hourly residential space heating demand using hourly electricity consumption data (smart meter data) and daily natural gas data from 30,000 customer accounts in Northern California. I apply linear regression to hourly, zip-code-averaged wholehome electricity consumption, zip-code-averaged whole-home gas consumption, and outdoor air temperature data to determine both the hours when heating is more active and the outdoor temperature dependence of that consumption. Using piecewise regression, I find that natural gas space heating begins, on average, when the daily outdoor temperature average drops below 59°F, with a mean temperature responsiveness of 0.13 therms per heating degree day (HDD). Therefore, when converting an 80% efficient natural gas furnace to an air source heat pump with a coefficient of performance (COP) of 3, we could expect an additional electric load of 1kWh of energy use per HDD below 59 F. Using a fixed effects model, I estimate the hourly pattern of this new heating load for each zip code analyzed.