The lowly service transformer – barrier to electrification

Today in the US there are over 35 million service transformers. They typically serve between 1 and 5 customers. Many are 50 years old or older, and the older ones at current load will likely run for 50 or more years yet.

Most are between 25 and 35 KVA (kilowatts for people who are not in the industry). That means one household can claim its “fair share” of 8 and 12 KW (assuming 3 households transformer). Households tend to draw about 2 KW as an average demand and hit peaks of 6 to 9 KW.

Now let’s have fun:

1)     Change the existing Heating and Cooling system to electric and add between zero and 15 KW to that existing demand for heat and the temperature.

2)     Move from a natural gas hot water heater to a whole house tankless hot water system – an addition of 15 to 37.5 KW

3)     Add an EV charger – 8 to 19.2 KW for a level 2 in the garage

4)     For some households add second EV charger

5)     Now covert the stove, oven and other gas fired appliances to the electrification bin. Another 2 to 12 KW

Yes, you are right not everything will be on at the same time. Yes, the 3 households on the transformer will not be on the same schedule. So, you have a chance to avoid changing the transformer.

But if they are all on at the same time, that 25 KVA transformer may see a load of more than 200 KW.

Currently the US changes out about 300,000 service transformers a year. Most utilities are on a 100–130-year schedule for change out, based on FERC Form 1 information.

So how do we change all 35 million in the next 8 to 22 years?

OBTW - no "the grid is OK" or "the grid will support all the EVs" report has mentioned service transformers