 # Transformer demand 2018 to 2028, and beyond

#### Background

Over the last thirty years, the global installed generating capacities have increased at a compound annual growth rate (CAGR) of 3.41 %, which means it has doubled over that time. Furthermore, the rate has been growing.

Back in 1988, the global generating capacity was growing at about 65,000 MW per annum (p.a.), and indeed during the decade 1988 to 1998, the average annual demand was a shade over 65,000 MW. However, it increased to an average of 124,000 MW p.a. in the following decade and to 224,000 MW p.a. during the period 2008 to 2018, Table I.

The installed capacities at each of those milestone years is displayed in Table II.

The resulting newly added capacities installed during each decade are displayed in Table III.

For the manufacturers of Generator Step Up (GSU) transformers, this is the basic ten-year production planning model.  Or, to be a little more accurate, the apparent power in GVA of GSU required to meet the active power in GW demands needs to be multiplied by a factor of approximately 1.1 on the basis that the GSU transformer is usually oversized by 10 %.  It is a small factor, but it increases the average annual apparent power demand up to 71.7 GVA, 136.7 GVA, and 246.7 GVA, respectively. This is the starting point for any estimates for future transformer demand. As far as any statistics can be termed as fact, these are internationally recorded and verified factually correct demand figures.

### If the average generator has a working life of 30 years, then the implied replacement rate is 3.3 % per year, which means that the replacement rate in any single year is equal to 3.3 % of the total installed capacity 30 years ago

There is, however, another element that should be added to the total global demand. Those are the capacities which should replace the old generating plants which are retired every year.  That is not easy to calculate, and it may require complex mathematical models for an accurate estimate. However, it can be estimated to a reasonable level of accuracy much more simply under some assumptions as follows.  If the average generator (across all types in every country) has a working life of 30 years, then the implied replacement rate is 3.3 % per year, which means that the replacement rate in any single year is equal to 3.3 % of the total installed capacity 30 years ago.  On this basis, the replacement of generator units in GW per decade is shown in Table IV.

This results in a total apparent power in GVA of GSU transformer demand over the period to be as shown in Table 5, which takes into account an additional 10 % increase in GSU rating due to usual oversizing.