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-> Proposal for an International Energy
Association Initiative to Promote Energy-Efficient Distribution
Transformers
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| Proposal for an International Energy Association
Initiative to Promote Energy-Efficient Distribution Transformers |
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A position Paper prepared by the IEA
Secretariat Energy Efficiency Working Party 24- 25 September
2001
1 Background
1. Transformers (excluding those used in small appliances) can
be divided into three groups : generation, transmission and
distribution. The first two types are used in the transmission
network linking electric generators with the distribution network,
which provides power to end users. Distribution transformers
are by far the most numerous and convert high-voltage electricity
to lower voltage levels for use in home and businesses.
The main reasons for considering an initiative on energy-efficient
transformers are given below.
2. The large number of distribution transformers in use and
the fact that all electric power generated world-wide continuously
passes through them implies that even small improvements in
transformer efficiency can result in substantial energy and
greenhouse gas savings.
3. Despite high average efficiencies (from 95 to 99.75%), transformers
have a significant environmental impact because they continuously
consume power. This might be considered as a 2nd standby loss,
after the standby power loss in electrical equipment.
4. The energy losses in electricity transformers fall into two
components : no-load losses or iron losses (resulting from energising
the iron core; this phenomenon occurs 24 hours per day, 7 days
per week, over the lifetime of the transformer, 30 years in
average) and load losses (arising when providing power to a
user, from the resistance of the coils when the transformer
is in use, and for eddy currents due to stray flux). Transformers
may lose 1 to 2% of energy transformed as heat when they are
lightly loaded.
5. Electricity distribution transformers have a relatively long
life (estimates range from around 30 years to as much as 50
years for lightly loaded or refurbished transformers), and individual
transformers accumulate substantial losses over their working
life.
6. In several OECD countries, electricity networks are responsible
for purchasing most of the transformers, while the cost of transmission
and distribution losses are passed on to consumers. As a result,
little market incentive exists to purchase efficient transformers.
7. Distribution transformers are used all over the world to
distribute power from large power stations to millions of end-users.
In the OECD area, there are over 60 million distribution transformers
(Australia 590,000 units, European Union 4 million units, Japan
13 million units, USA 40 million units). There are 3.3 million
units in China.
8. In most electricity grid, up to 2% of total electricity generated
is estimated to be lost in distribution transformers, representing
nearly one-third of overall system losses. This represents about
5.5 TWh in Australia (resulting in 5.4 million tonnes of CO2
in 1998), 90 TWh in China, 50 TWh in European Union countries,
32 TWh in Japan and 61 TWh in United States (resulting in annual
greenhouse emissions of 45 million tonnes of CO2). For comparison,
in the European Union, to compensate the energy losses in distribution
transformers, it takes about eight largest nuclear stations.
9. Power generation is one of the largest contributors to toxic
emissions and global warming (SOx, NOx and greenhouse gas emissions)
in OECD countries. Initiatives to reduce emissions, and meet
agreed climate change and global warming targets, are often
similar to those aimed at improving energy efficiency. Most
countries have programme involving the electricity industry
to help meet the global warming targets set in the Kyoto Protocol.
10. Newly privatised utilities are reported to show less interest
in longer-term problems. They usually require more rapid paybacks
on their investment compared to the public sector network operators
they have replaced.
11. Distribution utilities, when managing transformers and other
equipment, try to minimise capital expenditure, particularly
through assets management.
12. The existing stock of distribution transformers is ageing,
with many transformers over 40 years old. In several OECD countries,
the age profile of the power transformer stock is widely regarded
as a cause for concern.
13. The main sources of distribution losses are transformers
and cables, unmetered and unbilled supplies.
14. According to the size of the commercial and domestic sectors,
as much as 75% of all electricity generated in several OECD
countries is consumed at low-voltage. This proportion is likely
to increase, since domestic and small commercial loads grow
while heavy industry declines. This suggests that distribution
transformer losses will grow.
15. A recent study performed for the European Commission1 estimates
that about 22 TWh per year could be saved in the European Union
through the use of energy-efficient distribution transformers
(representing 3% of the European commitment to reducing carbon
emissions), worth 1,171 million euro at 1999 prices. In Japan,
the Top Runner Programme extended to distribution transformers,
could save about 24 TWh per year. In the United States, the
potential is about 45 TWh per year ; in this country alone a
0.01 percent gain in the average efficiency of utility transformers
installed in a single year would produce an energy savings of
2.9 TWh. In China, the potential saving is about 47 TWh per
year.
16. The environmental benefits of energy-efficient transformers
are very high. A 400 kW transformer, typical for urban distribution,
has lifetime losses equivalent to 125 - 184 tonnes of CO2 emissions.
Electricity losses cost two to three times more than the original
purchase price of the transformer. An energy-efficient transformer
could reduce CO2 emissions to 56 tonnes (figures for The Netherlands).
17. In Europe, if all electric appliances and end uses were
turned off, six of the largest nuclear power stations would
be still needed to compensate for transformer losses, and another
six for standby power losses from electronic equipment.
18. Transformers could emerge as a major focus for energy efficiency
initiatives in OECD countries, comparable with electric motors,
domestic appliances, etc. They are potentially capable of making
a similar contribution to reducing carbon emissions and achieving
global warming goals.
2 Technical considerations
19. Technical solutions exist to reduce transformer losses by
75% at minimum (when replacing with modern transformers) or
even by 90% (when replacing transformers over 30 years old).
Energy-efficiency can be improved with better transformer design
(selecting better, lower-core-loss steels; reducing flux density
in a specific core by increasing the core size; increasing conductor
cross-section to reduce current density; good balancing between
the relative quantities of iron and copper in the core and coils;
and so on.), or by the adoption of amorphous iron transformers
world-wide (distribution transformers built with amorphous cores
can reduce no-load losses by more than 70% compared to the best
conventional designs).
20. High-efficiency transformers are available and already used
by the utility industry. Producing energy-efficient transformers
is not a technical challenge. The technology is available in
all OECD countries.
3 Economic considerations
21. Transformers use well-established technologies and designs,
and equipment can be manufactured in relatively low-cost facilities.
For this reason the manufacturing sector - working in close
relationship with its utility customers, supplying mainly power
cables, transformers and switch-gear has always been very price
competitive.
22. Utility's investment in energy-efficient distribution transformers
has an economic payback time between 1.4 and 8 years, and an
internal rate of return between 70% and 11%.
23. There are a variety of additional cost savings and benefits
associated with energy-efficient transformers. They include
:
• reduced physical size (unit dimensions);
• reduced transformer heating, hence lower need for additional
cooling or insulation (hence reduced variable costs such as
coolants, ageing insulation materials);
• reduced noise levels;,
• longer operating lifetime.
Low-loss transformers also better withstand electronic (harmonic)
loads.
24. As utilities enter an era of increased competition, they
must find ways to cut costs while improving the quality of service
to their customers.
25. Despite the benefits of energy-efficient distribution transformers,
it is a challenge to convince customers that, although the initial
price associated with these transformers is higher, the overall
cost using them can be lower.
4. A favourable context for co-ordinated international action
26. In a context where governments are trying to find ways to
reduce their greenhouse emissions in a cost-effective way, eliminating
unnecessary electricity losses from distribution transformers
represents an interesting avenue. Moreover, the stock of distribution
transformers will continue to grow -driven by e electricity
market de-regulation in most OECD countries (The trend toward
generating electricity at sites close to the point of use suggests
a decreasing need for transmission across long distances, but
will increase the need for smaller transformers in the network.)
As a result, losses from distribution transformers will represent
an even larger share of electricity use.
27. Yet, take-up of efficient transformers has been low. Markets
deregulation has forced utilities to reduce capital budgets.
Since energy losses are directly charged to customers via tariffs,
reduced losses do not necessarily benefit the investor.
28. Several countries are facing significant growth in electricity
demand. They could benefit greatly from installing energy-efficient
transformers.
29. The environmental, energy efficiency and economic arguments
for efficient distribution transformers are clearly understood
by actors and decision-makers in the electricity sector, creating
an increasingly positive climate for dialogue.
5. Existing initiatives
30. In Canada, Natural Resources Canada (NRCan) has proposed
minimum energy performance standards for transformers. In 1997,
NRCan distributed a proposal to stakeholders and has subsequently
consulted widely. The proposed regulations, based on the US
NEMA guidelines to harmonize regulation within North America,
were introduced in January 2001.
31. In Australia, the National Appliance and Equipment Energy
Efficiency Committee (NAEEEC) is exploring the benefit of mandating
minimum energy performance standards (MEPS) for electricity
distribution transformers. MEPS is a government regulatory program
stipulated in state and territory law that excludes from the
market products which do not meet the minimum energy performance
levels. The MEPS for distribution transformers, matching the
Canadian standards proposed to take effect in early 2001, will
come into force by approximately mid-2003. Cumulative savings
by 2015 resulting from the introduction of MEPS in 2005 are
estimated to be at least 346 thousand tons CO2 and could be
as high as 950 thousand tons CO2.
32. In the United States, the Environmental Protection Agency
(EPA) has included transformers into its Energy Star labelling
scheme. The Energy Star Transformer Program is a voluntary energy
efficiency programme designed to encourage utilities to purchase
and install high-efficiency, cost effective transformers in
their distribution systems. Consideration is being given to
setting minimum standards for distribution transformer losses.
This programme includes information and software dissemination.
Technical assistance is provided to partners to ensure that
transformers are not oversized. Distribution Transformer Cost
Evaluation Model (DTCEM) is available that provides a standard
methodology for evaluating multiple transformer bids.
33. The US Department of Energy (DOE) Federal Energy Management
Program also encourages government procurement of energy-efficient
distribution transformers. Starting in 1998, the DOE began a
process of research and consultation on the merits and potential
levels for a minimum energy performance standard (MEPS). No
firm implementation commitment has been made to this so far.
However, industry-wide consultations are being carried out and
test procedures are being developed. Possible references on
which to base standards include the ANSI/IEEE standards or the
NEMA standard. It is envisaged that minimum energy performance
standards will be adopted for transformers by approximately
mid-2003
34. Mexico is among the most advanced countries in the enactment
and implementation of minimum energy performance standards and
energy efficiency labelling. Much of the effort has borrowed
from the United States experience, although a good deal has
also been developed in response to local requirements. Minimum
energy performance standards and energy labelling have been
implemented to reduce the growth in electricity demand. The
Energy Performance Standards cover energy efficiency and safety
for distribution transformers and became mandatory in 1999.
They also prescribe the maximum allowed losses, which is not
the case in either the United States or Canada.
35. In Europe, CENELEC has, for ten years, applied a voluntary
standard for transformer losses for each of the harmonised distribution
transformer sizes: HD428 for oil-cooled transformers and HD538
for dry-type transformers. However, HD428 allows for different
levels of efficiency, none of which are technically challenging.
Purchasers are allowed to choose loss evaluation techniques,
effectively determining their own standard. The current national
standards of European Union countries and major utilities are
based upon HD428. There are no plans to create a European Standard
(EN) from HD428.
36. However, discussions have already taken place between the
European Commission (DG TREN), COTREL (Industry Representatives)
and EURELECTRIC to discuss the possibility of voluntary agreements
or a European Directive on reducing losses from distribution
transformers through a minimum standard.
37. In Japan, transformers will be added to the Top Runner scheme
in 2002. For a given equipment, the energy efficiency target
to be met by the whole market is set at the level of today's
best available equipment (the Top Runner). Therefore, the specified
performance level for transformers is based on the performance
of the best currently marketed equipment and short-term technology
development. The Amorphous Industrial Transformers (AMIT) is
actually the most efficient but standards will be set at a lower
level.
38. China banned some transformers (referred to as S7) in January
1999, and moved the market effectively to the S9 level (about
30% higher losses than OECD state-of-the-art).
6. Need for action at international level
39. Several OECD countries are developing policies to promote
energy-efficient distribution transformers.
40. However at the present stage, few OECD countries have formal
national energy efficiency plans in place for distribution transformers,
although these are being drafted to help fulfil global warming
commitments.
41. The savings potential from distribution transformers may
appear too small and too difficult to achieve to be considered
at national level. However, for the OECD, potential savings
can be estimated at 150 TWh per year, representing an emission
savings of 75 million tonnes of CO2. This is equivalent to about
30% of the European Union's Kyoto commitments.
42. Both utilities and non-utility purchasers are difficult
to influence. However, the transformer market is extremely competitive
and the sector involves a limited number of professional buyers,
already reasonably aware of the arguments for energy efficiency.
The energy-efficient transformers initiative could help partners
of the supply chain to be receptive to arguments for these transformers,
provided that benefits issuing from the promotion of such equipment
are clearly demonstrated.
43. In developing countries, where help is needed in electricity
generation, in energy efficiency and in standard utility operational
expertise, the potential savings are greater than those in the
OECD region.
44. Current efforts to promote energy-efficient distribution
transformers could accelerate and benefit from a co-ordinated
approach.
7. An IEA led effort
45. IEA is well placed to co-ordinating an initiative on energy-efficient
distribution transformers. The successful introduction of a
world-wide initiative on energy-efficient transformers would
strongly reinforce the existing national programmes.
46. The IEA proposes to organise an International Workshop in
2002 to discuss the issue of electricity losses due to distribution
transformers and explore the possibility of organising international
collaboration to facilitate domestic efforts. During the workshop,
a number of issues will be discussed, such as the magnitude
of the electricity waste in various economies and the related
CO2 emissions, existing technical solutions and their cost-effectiveness,
and the various policies that could be used to tackle the problem.
Discussions could help to produce recommendations targeted to
policy makers.
47. An initiative on energy-efficient distribution transformers
could be linked to the IEA Ad-Hoc Group of Experts on Electric
Power Technologies. The aim of the initiative could be to facilitate
setting high transformer standards and stimulate programmes
for replacement of older transformers. 8 Conclusion
48. Distribution transformers appear to be a attractive candidate
for an internationally co-ordinated energy efficiency initiative
and a worthwhile area for R&D, demonstration and promotional
efforts.
49. The majority of OECD countries are currently developing
strategies to decrease greenhouse gas emissions. The potential
for reducing losses from distribution transformers could be
considered as an element of world-wide strategies to address
energy efficiency, global warming and environmental impacts.
50. The energy-efficient transformers initiative could impact
the world market, benefiting to economies outside those of the
OECD.
References :
1. European Commission, The scope for energy saving in the EU
through the use of energy-efficient electricity distribution
transformers, December 1999.
2. Mark Ellis & Associates, Analysis of Potential for Minimum
Energy Performance Standards for Distribution Transformers,
prepared for the Australian Greenhouse Office, March 2000.
3. United States Department of Energy, Framework Document for
Distribution Transformer Energy Conservation Standards Rulemaking,
November 2000.
4. International Copper Association - European Copper Institute,
Energy-efficient distribution transformers - Utility Initiatives,
December 2000.
5. E. Shibata and al., Suggestion for Reduction of the Second
Standby Power "No-load Loss", February 2001. |
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