In Numbers, How Can This Small Infrastructure Decision Help Achieve Net Zero

Transformer Losses

When the conversation of energy efficiency takes place, people immediately start thinking of ways to save energy inside the building (lighting, double glazed windows, inverter air conditioning, etc.) but very little think of transformers.

The main function of distribution transformers is to convert the electrical current from one voltage to another. Transformers waste energy as a by-product of their operation. The wasted energy happens in two forms; load losses and no-load (core) losses.

The EU estimates that 2.9% of all electricity generated gets wasted through transformer losses, according to 2008 across the EU27. That amounted to 93.4TWh which is enough to power Denmark for 3 years.

Regulations

The European Commission issued regulation No 548/2014 on implementing Directive 2009/125/EC regarding small, medium and large power transformers. The regulations are referred to as Ecodesign Directives for Transformer Losses Tier 1 and Tier 2. Tier 1 was effective as of the 1st of July 2015 and Tier 2 will come into force on the 1st of July 2021 (almost two years from now).

Tier 1 and Tier 2 regulate transformer losses by forcing most new built transformers to have better (less) losses.

Humble targets

The requirements for the three-phase medium power transformers with rated power<= 3150kVA, which are the most commonly used transformers, are humble. The EC went for reserved targets, the below table compares two products we have in the market vs. the regulated losses.

This has a disadvantage as it does not motivate suppliers to invest in their technologies to produce products with better losses.

The other disadvantage of the UK following these targets is that Tier 2 will be effective in two years from now. Many end users intend to replace their old transformers with Tier 1 losses not to have to comply with Tier 2. This is a wasted opportunity for the UK to settle for humble numbers when it comes to reducing its carbon emissions from this massive sector.

Carbon savings potential

Through the Freedom of Information (FOI), we made a request to Ofgem enquiring about the average age of transformers in the UK. The response was surprising that the average is 64 years. There are transformers that were installed in the 50s and are still up and running but unnoticeably, are silent energy guzzlers.

The idea age of a transformer should be around 30 years. Most tests are based on 25 years of operation. There is no law in place that forces owners to replace their old inefficient transformers with new eco-friendly and Eco Design compliant ones. And there is a lack of motivation as no incentives are given to transformer replacements or new builds if they are energy efficient.

The carbon trust manages the Energy Technology List (ETL) that is part of the Enhanced Capital Allowance (ECA) tax scheme for businesses. ETL allows businesses to claim 100% first-year capital allowance on products on the list. The ETL does not have ultra-low loss transformers on its list as an approved category.

There are 230,000 substations in the UK as of 2011. Some websites refer to more than 400,000 substations in the UK. Based on only 230,000 substations and assuming that every substation has one transformer of an average of 800 kVA and only 10% of them are old transformers and are ready for replacement.

This brings us down to 23,000 transformers. If replaced with Ultra Low Loss Transformers, that are Tier 2 compliant or even better, that saves the UK annually 772 GWh and 0.217Mt of carbon annually. This is equivalent to 2% of the reduced emissions between 2017 & 2018.