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Looking to fuel up
02-JAN-2006

The potential for generating energy from waste in the UK

Residual solid waste in the UK could be
used to create enough electricity to power 2 million homes each year and help
the UK meet its renewable energy targets. But inconsistencies in current legislation
are shackling this development. 

Almost 22 million tonnes of household waste were sent to landfill in England
alone in 2003. With this in mind, the Institution of Civil Engineers (ICE) and
the Renewable Power Association (RPA) examined the potential for exploiting
this resource in waste-to-energy (WTE) plants. The findings were published in
a joint report, entitled `Quantification of the Potential Energy from Residuals
in the UK¿ (April 2005).

The report focuses on the use of waste to generate electricity and has little
to say about the huge thermal efficiency gains that are possible from using
the same quantity of fuel in a combined heat and power (CHP) plant. Unlike many
other EU countries, the UK has always been reluctant to invest in the necessary
infrastructure to effectively utilize (such as in a district heating system)
the heat energy inevitably released in a WTE plant, or indeed any thermal power
station.

Focusing on residual waste (the waste remaining after recycling and compost
recovery), the three primary objectives of the ICE and RPA study were to determine:

• the potential electrical yield from the UK¿s residual waste up to 2020
  


• the potential contribution that energy recovery from residual waste could
  make to the UK¿s target under the European Union¿s Renewables Directive


• the potential additional contribution to the Renewables Obligation if eligibility
  for Renewable Obligation Certificates (ROCs) were extended to encompass all
  energy recovery techniques.

POTENTIAL ELECTRICITY YIELD FROM THE UK'S RESIDUAL WASTE

Despite all efforts to the contrary, the UK¿s electricity demand has risen
by 1.5%¿2.0% per annum over recent years ¿ less than the annual growth rate
of the country¿s waste output. Electricity supply had risen to meet the increasing
demand from 364 TWh in 1999 to 393 TWh in 2004. During this time, the amount
generated from WTE plants had been steady at around 2%.

Waste-to-energy plants currently in operation typically process between 20,000
and 600,000 tonnes of waste per year and generate 1¿40 MW of electricity from
this fuel (plants with capacity of up to 1,000,000 tonnes/year are being planned).
According to the ICE¿RPA study, the UK has the opportunity to produce up to
17% of its electricity by 2020 using just the residual amounts of municipal
solid waste (rMSW) and commercial and industrial waste (rC&I) ¿ see Figure 1.
The ICE¿s State of the Nation report (October 2005) confirms this, adding
that `a more realistic but still very significant contribution would be 10%¿.

One piece of legislation is trying to phase out landfills, while another is encouraging landfill and discouraging WTE

MEETING EU TARGETS

Under the EU Renewables Directive, the UK has made a commitment to generate
10% of its electricity from renewable sources by 2010. This target has been
extended to 15% by 2015, while the 2003 Energy White Paper has the aspiration
of achieving 20% by 2020.

However, Peter Gerstrom, Chairman of ICE¿s Waste Management Board, is sceptical
that the UK will meet any of these targets: `We are not generating enough renewable
electricity. It is unlikely that we will reach our 2010 target and even less
likely that we will reach 20% by 2020. Instead of burying rubbish that is left
after recycling, it can be used to generate renewable power. This is also an
effective way of hitting the targets in the EU Landfill Directive.¿

According to ICE/RPA projections (Table 1), wasteto- energy could theoretically
contribute towards the UK targets, and the potential energy recovery from residual
biodegradable waste could exceed the UK¿s 2010 target under the EU Renewables
Directive.

RENEWABLE OBLICATION CERTIFICATES (ROCs)

The Renewables Obligation (RO) has been introduced to transpose the requirements
of the EU Renewables Directive into UK legislation. It requires electricity
suppliers to source an increasing percentage of their sales from renewables.
Inexplicably, the Government has, so far, not followed logic and legislated
for a parallel Renewable Heat Obligation (RHO), even though this would be significantly
more effective in reducing greenhouse gas (GHG) emissions than the electricity-only
RO can ever be. An RHO would also stimulate the construction of many more CHP
plants fuelled by renewables and waste, rather than the low-efficiency, electricity-only
plants presently being built.

Waste can never truly be regarded as a `resource¿ while it is still viewed primarily as a problem

Under current legislation, electricity generated from waste counts towards
the RO only if it is converted through landfill gas or by using so-called `advanced
technologies¿ such as anaerobic digestion, gasification and pyrolysis. From
an engineer¿s standpoint, it is illogical that `combustion¿ of waste is not
considered as advanced as, say, anaerobic digestion (a rather primitive process),
while it defies belief that landfill gas recovery is eligible for ROCs. It appears
contradictory that one piece of legislation (the Landfill Directive) is trying
to phase out landfill sites, while another (the Renewables Obligation) is encouraging
landfill and discouraging WTE.

TABLE 1. The potential contribution to the UK¿s 2010 target under the EU Renewables Directive using energy recovery from residual biodegradable waste. SOURCE: QUANTIFICATION OF THE POTENTIAL ENERGY FROM RESIDUALS IN THE UK, ICE/RPA
	Electricity (TWh)
Obligation to produce 10% of the UK¿s electricity with renewables by 2010	35.5
Potential electricity generated from:
Residual biodegradable municipal waste (rBMW)	15.7
Residual biodegradable commercial and industrial waste (rBC&I)	24.8
Total from biodegradable waste	40.5

LIMITATIONS OF THE ICE/RPA REPORT

The ICE/RPA Report is valuable in identifying the very significant potential
that WTE offers towards meeting the UK¿s renewable electricity targets. It is
also helpful in showing that the amount of electricity which can be generated
from just residual biodegradable waste can make a worthwhile contribution to
these figures. However, it misses an opportunity to take the Government to task
over several inconsistencies in current policy and legislation:

• The report only considers residual waste, defined as `waste remaining
  after the recycling and composting fraction has been removed¿. This presupposes
  that recycling and composting are the most useful way of treating waste in
  order to achieve the Government¿s GHG emissions targets, which is manifestly
  not always the case. Reducing the level of GHGs emitted to atmosphere is surely
  the real goal to be achieved, rather than recycling and/or composting targets,
  which can only ever be a possible means to an end, not the end itself.

• Almost every form of recycling requires the input of significant quantities
  of energy from external sources, which in the UK are primarily produced from
  fossil fuels. Composting internally generates a large quantity of heat energy,
  but usually this energy cannot be utilized and is therefore `wasted¿. Both
  recycling and composting are generally net producers of GHGs, and exacerbate
  the overall emissions problem. WTE, on the other hand, can produce large quantities
  of both heat and electrical energy, which replace the same amount of energy
  produced from fossil fuels such as coal or gas. It is astonishing that current
  legislation is so heavily biased towards the encouragement of GHG emissions,
  rather than the abatement of them, which would be logical in order to meet
  the Government¿s 2050 target of 60% reduction in GHG emissions.

• The report frequently goes along with the misuse of the term `incinerator¿
  to describe a WTE combustion plant. While this term may have become enshrined
  in an EC directive and the subsequent UK legislation (the Waste Incineration
  Directive), it is very misleading because it suggests that the primary intention
  of a WTE plant is to destroy problematic waste. Waste can never truly be regarded
  as a valuable `resource¿ while it is still viewed primarily as a problem.
  Modern WTE combustion plants use waste as a fuel, in the same way that a conventional
  coal-fired power station uses coal and a combined-cycle gas turbine uses natural
  gas; yet it would be unimaginable to refer to them as coal or gas incinerators.
  

TIME TO JOIN UP THINKING

Waste-to-energy has an important role to play in improving energy security
in the UK by reducing dependence on energy imports, minimizing the amount of
waste going to landfill and ¿ by virtue of its biomass content ¿ making a valuable
contribution towards the UK¿s renewable energy targets. Taking into consideration
the decisions already made by local authorities about their choice of wasteprocessing
technologies, the ICE¿RPA analysis indicates that energy from residual waste
could still contribute over 20% of the UK¿s target for renewable electricity
generation.

To again quote from ICE¿s State of the Nation report, `The past 12 months
have continued to show the denial and disconnected thinking with which the Government,
businesses and the public approach the subject of waste. In this country, waste
is seen as an end ¿ a dead end ¿ rather than a means. That view has to change.¿

Ian M. Arbon is Senior Partner at Engineered Solutions,
UK and Chairman of the Energy, Environment & Sustainability Group of the Institution
of Mechanical Engineers, UK.

e-mail: ian.arbon@engineered-solutions.co.uk

At the time of this article going to press, it was revealed that the UK government
may be preparing to back a substantial increase in the proportion of waste to
be disposed via wasteto- energy. To access the full ICE¿RPA report, go to: www.r-p-a.org.uk/article_default_view.fcm?
articleid=1268&subsite=1

 

 

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