The European Commission estimates that 2.9% of all energy generated across EU27 and the UK is wasted through transformer losses. This amounts to 93TWh which is equivalent to the electricity consumed in Denmark over three years.
Network losses account for 1.5% of the UK’s greenhouse gas (GHG) emissions. 25% of these emissions are caused by distribution transformer losses. Due to the inefficiencies of old transformer designs and the level of losses associated with them, Ecodesign regulations were launched to minimise the energy waste of transformers.
Ecodesign Regulations for Transformer Losses
EU Commission Regulation (EU) No 548/20141 and Amendment (EU) 2019/17832, which were then adopted by the UK, introduced requirements for Load and No-Load Losses for distribution and power transformers placed in the market or put into service within the region. Tier 1 came into effect in 2015 and Tier 2 followed in 2021 with stricter energy loss requirements ensuring that transformers installed on the network are built with efficiency in mind.
Wilson Power Solutions, a transformer manufacturer based in Leeds, launched Europe’s most energy-efficient distribution transformer last month. Wilson e4 Ultimate Low Loss Amorphous® Transformer is a breakthrough in transformer efficiency introducing 27% lower combined losses than Ecodesign Tier 2.
All new transformer installations in the UK have had to follow Ecodesign Tier 2 standards since July 2021. Upgrading to the Ultimate Low Loss transformer incurs additional CAPEX investment but that is offset in a two-year payback period based on a 70% load factor and £0.25/kWh. Payback calculations are recommended and there are many online tools to help organisations look at the full lifetime costs of owning that transformer. The paybacks are generally more favourable with transformers that are highly loaded or with organisations that pay more electricity tariff than others.
Amorphous Metals Explained
The traditional transformer core technology consists of stacks of laminations that are made from silicon steel with an almost uniform crystalline structure, referred to as Cold Rolled Grain Oriented Silicon Steel (CRGO). CRGO transformers have reached their full potential making it difficult to further reduce the losses without incurring significantly higher costs.
Amorphous metals are made of alloys that have a random molecular structure caused by the rapid cooling of molten metals that prevents crystallisation and leaves a vitrified structure in the form of thin strips. Due to the random molecular structure, friction is reduced in the magnetisation demagnetisations of the core resulting in less heat dissipation which boosts the transformer’s overall efficiency.
Transformer Losses
Energy waste through transformers is mainly split into two main types: Load Losses and No-Load Losses. It is pertinent to address both to improve the efficiency of the transformer. Load Losses are sometimes referred to as winding losses and are a result of the load on the transformer. These losses depend on the current flow through the transformer windings and occur due to their resistance. No-Load Losses are dependent on the core material, and they are present 24/7 from the moment of energisation regardless of the load.
Due to the random molecular structure of Amorphous metal core, there is less friction during the magnetisation and demagnetisation resulting in less energy waste in the form of heat. This results in less hysteresis losses in the transformer.
The resistivity of the core is proportionate to the square of the thickness of its laminations. The strip thickness of Amorphous laminations is 0.025mm (10 times less than CRGO) and has a 0.32g/cm3 lower density compared to conventional CRGO. This results in less Eddy Current Losses which are caused by the induced currents of the transformer core due to alternating magnetic fields.
Untapped Decarbonisation Potential
Through a Freedom of Information request we submitted to Ofgem, we found out that the average age of a distribution transformer in the UK is 63 years old. Despite durable design capabilities allowing transformers to live much longer than anticipated, older designs paid no regard to efficiency. Conventionally, the older the transformer, the more energy it wastes.
Looking at the Life Cycle Assessment (LCA), on average, 95% of carbon is emitted during the operational and maintenance phase of the transformer. Hence, the energy efficiency of the transformer design is paramount to decarbonisation. And this means old transformer assets have a significant role to play through upgrading and replacement programs.
When conducting a life cycle cost analysis associated with replacing old transformers, it is important to understand that the benefit goes beyond the financial feasibility extending to carbon reduction and reliability advantages. The table below shows the potential energy, carbon, and financial savings from replacing old transformers with Wilson e4 Ultimate Low Loss Amorphous® Transformer.
Website: www.Wilsonpowersolutions.co.uk
Author: Ayah Alfawaris, Head of Group Sustainability & Marketing
This article appeared as the cover story in the .