Memorandum by Mr Paul Spare
INTRODUCTION
1.1 The House of Lords has initiated an
enquiry into the costs of Renewables. This submission is
made in response to their Lords' request. I am a retired chartered
engineer, having worked for Rolls-Royce for five years, gas industry
for four years and almost 30 years in the nuclear field, from
design to decommissioning. Since the privatisation, I have written
many papers and letters warning of the danger of a short term
energy policy and the adverse environmental effects of renewable
power sources. It discusses some costs, but concentrates on the
engineering issues from which in time, cost estimates made be
made. Many Renewables are so impractical that would render all
investments at best profligate and at worst—pointless.
1.2 In March 2007, EU leaders accepted a
proposal to utilise more renewable energy to reduce CO2 emissions—foolishly
excluding nuclear generation, that is not only the largest carbon-free
source of generation, but the largest source of electricity. They
backed a mandatory cut in the EU's CO2 emissions of 20% below
1990 levels by 2020. On 23 January 2008, José Barroso,
the EC President, reiterated this position. All 27 European Union
countries will be set targets for renewable energy use to ensure
that 20% of EU energy comes from renewables by 2020. The UK's
renewables target is expected to be set at about 15%. (Note, this
is stated as energy and not electricity).
1.3 Renewable energy schemes may not bring
low CO2 emissions because, being intermittent, they must be backed
up by reliable plants (Paul Golby, E.ON UK's chief executive Ref
1). The lowest CO2 emissions are produced not by Denmark with
its thousands of wind turbines, but by Sweden, France and Switzerland
where electricity is derived from nuclear power and hydro-electricity.
Per capita emissions in Denmark are twice as high as France.
1.4 The 2003 Energy White Paper (Ref 2)
also proposed that renewable forms of electricity should generate
20% of UK electricity by the year 2020. The PIU ignored specialist
engineering advice that, unlike conventional coal, gas or nuclear
plants, where a 1,000 MW is scaled up from a 100 MW plant and
is about the same size, renewable plants can only gather diffuse
natural energy and must multiply in investment, pro rata to achieve
increased output. They benefit little from "economies of
scale".
1.5 The remainder of this paper explains
some of the adverse consequences of massive expansion of renewables
to achieve 20% to UK electricity/energy supplies, presenting costings
where possible.
ELECTRICITY GENERATION
2.1 The EU plan requires Europe to generate
20% of energy/electricity from renewable sources by 2020. What
quantity of energy does this represent? The annual review of energy
consumption in the UK by the DTi states that the total amount
of electricity generated in 2006 was 395/405 TWh (Ref 3 Table
5.2). Electricity consumption in the UK shows a growth of 1 to
2% per annum (typical for Europe) and has increased by 40% since
1980. If the trend continues (at 1.5%), electricity consumption
in 2020 will reach 500 TWh. The DBRR recently projected that electricity
generation will actually decline up to 2010 and increase in 2020
to only about 410 TWh. Such modest growth is based on hope, not
recent evidence.
2.2 If it is assumed generously, that conservation
measures/efficiency measures will reduce consumption, a lower
output may suffice. The analysis below uses a compromise assumption—that
growth of electricity will reduce, that generation will increase,
but only to 450 TWh. A 20% renewables contribution would therefore
be 90 TWh and ca 105 TWh if recent trends continue up to 2020.
QUANTITY OF
RENEWABLE ENERGY
3.1 Section 4 of the PIU Review (Ref 4)
contains the following statement concerning renewable options.
The technologies with the largest potential in
the UK are on- and off-shore wind, wave and tidal stream, solar
photovoltaics and biomass (energy crops and agriculture and forest
materials), and large hydro—though most large hydro potential
has already been harnessed. Smaller contributions are possible
from a range of other technologies, such as small hydro and solar
water heaters. A significant contribution could also come from
large estuarine tidal barrages, most notably the Severn barrage.
3.2 Various combinations can be postulated
for the mix of generation that would provide the 90 TWh of electricity,
but one approach is to extrapolate from the current situation.
The table below shows recent trends. DTi data gives the contributions
to electricity in 2001 as hydro—1%; other renewables—2.5%.
Data for 2005 adopts a slightly different approach. Typically,
the renewable contribution to energy supply is about 3.1 mtoe
ie just over 1% of total UK energy consumption (240 mtoe). Renewables
are shown with the following percentage split (also including
minor non-electricity use for some fuels).
|
| Fuel Type | Percentage Contribution 2001
| Percentage Contribution 2005
|
|
| Landfill Gas | 27
| 33.4 |
| Waste combustion | 31.5
| 10.8 |
| Wood biofuels | 16.6
| 28.1 |
| Domestic and Industrial wood | 15
| 6.7 |
| Sewage gas | 5.4
| 4.2 |
| Wind and wave | 2.7
| 5.9 |
| All Hydro | —
| 10.1 |
| Small hydro | 0.6
| — |
| Geothermal and active solar | 0.4
| 0.7 |
|
3.3 The most important point is that two of the most
significant contributors are landfill gas and waste incineration.
These are excluded from the current list of acceptable "renewables",
as is large hydro. The current contribution to electricity from
acceptable renewables in 2007 is only about 1%. The largest
renewable contributor is conventional hydro, but new schemes are
considered environmentally unacceptable. The 1,000+ turbines produce
less than 1% of UK electricity. The three largest contributors
are thus to be discouraged; so that the expansion required from
the acceptable renewables is even greater than might at
first appear.
3.4 The suggested contributions given below for renewable
electricity in 2020 are therefore of necessity, different from
extrapolating the current contributions, but the subdivision below
is proposed as credible, using the small number of renewable options
that are available and acceptable.
1. Wind power (on shore and off shore) 50%—45 TWh.
The implications of achieving these contributions from the
selected renewables are considered below.
WIND POWER
4.1 Wind power is usually considered as the first choice
renewable power source. For this reason, it is assumed in this
study to provide the greatest share of supply in 2020 (45 TWh).
There are already about 2,000 MW of installed capacity, with plans
for more capacity both on land and offshore. Growth year-on-year
has been steady, with 7 GW of new capacity in the planning process.
4.2 The largest wind turbines have a maximum continuous
rating of 3 MW. The 3 MW turbines are not acceptable at all sites,
because of their massive height and base anchorage requirements.
It is therefore prudent and conservative to assume an average
machine size of 1.5 MW in calculating the number of machines required
far into the future. A 1.5 MW turbine operating continuously for
a year would produce 13,140,000 kWh and 3,290,000 kWh with a typical
25% load factor. To generate 45 TWh would require 13,700 turbines.
If the average construction rate achieved in the last few years
were to continue, it would take about 50 years to construct that
number of turbines.
4.3 Although as industrial equipment, turbines should
be built in industrial areas, developers prefer remote unspoiled
areas because the wind blows at higher speeds. To obtain access
to such sites involves costs for the quarrying and transport of
hundreds of thousands of tons of aggregate for roads and bases.
4.4 If 10,000 were to be installed offshore, it would
require a rate of two per day over the next 13 years. Since bad
weather will prevent construction offshore in the winter, it will
be necessary to erect at the rate of four per day. These construction
rates look impossible with the small number of lifting barges.
A 2.5 MW wind farm in the Baltic Sea, comprising five 500 kW turbines,
4 km off the south western coast of Gotland, Sweden, took five
months to complete (Ref 5). The Greater Gabbard Offshore Farm
off the Thames estuary, with 140 turbines, will not commence construction
until 2009 and will take several years to complete—and average
of about 1 per week (Ref 6). Offshore wind turbine costs must
also be increased to include the removal of the 30 metre long
piles that are driven into the sea bed to support them. These
must not be left to corrode and pollute the coastal waters.
4.5 The UK power system is based upon a 400 kV Grid Transmission
system, which delivers the large flows of power from some 100
large (>500 MW) geographically dispersed plants, through bulk
supply points to the low voltage distributors. This historic practice
has minimised infrastructure costs. There are often no HV grid
connections where wind farms are to be constructed, so new power
lines will also have to be erected, with transformers, switchgear
and protection equipment. The north west coast of Scotland, being
sparsely populated, has no high voltage (400 kV) supergrid lines.
Complete new transmission systems would therefore need to be installed
to transfer the power from the new wind farms. The Beauly-Denny
link is forecast to cost over £300 million to bring power
from the most northern wind farms.
WOOD BURNING
5.1 Biomass plants (power stations burning firewood)
are now being proposed for future power supplies. They can achieve
higher load factor—65%—than many renewable energy
sources and also generate heat rather than electricity. To generate
18 TWh per annum would require 3,160 MW of such plants. The calorific
value of the coppice biomass material will be at best about 33%
that of crude oil, even when dried. An electrical output of 1,000
MWe requires about 1.4 million tons of oil per year and 4.43 Mtoe
to generate 3,160 MW. Therefore 13.3 million tons of wood would
have to be burned to generate 3,160 MW.
5.2 The Forestry Commission has estimated the maximum
production of wood from coppicing to be 6.8t/acre per annum—17t/hectare
or 1,700t/km2. Hence 13.3 million tons of wood would require about
7,815 km2 to be harvested each year this is three times the area
of an English county such as Suffolk.
5.3 The environmental damage is not restricted to the
appearance. The transport of 13 million tons of wood would have
very severe adverse effects on the rural communities, agriculture,
the roads and the wildlife. If there were 73 power plants rated
at 50 MW, each would require 200,000 tons of fuel annually, or
100 lorry loads per day. The ash from wood burning may be a hazardous
waste and require costly treatment before it could be sent to
landfill.
SOLAR
6.1 Solar power in the UK can take two forms—direct
heating of hot water as part of a pre-heat system or use of photovoltaic
(PV) cells. Only PV cells are considered here. Solar power appears
attractive because the output of the Sun will remain unchanged
for thousands of years. That is correct, but there are long periods
with little or no sun in the winter. PV cells produce no electricity
at night, nor in cloud or fog, so that solar is worse than wind,
since its output tends toward counter-correlation with demand.
To generate the 9 TWh per annum would require 6,860 MW of installed
cells (assuming an optimistic 15% availability—that is about
four hours per day average sunshine).
6.2 It requires an area of panels of 10,000 m2 to produce
reliable power at the rate of 1 MW. For a house to generate 2
kW, requires panels with an area of 20m2. This is about the limit
for the average modern house roof, supported on trusses. It would
take 5,000,000 houses to generate the power required for the solar
contribution. That is about 25% of the UK housing stock.
6.3 There will also be a severe problem with component
disposal at the end of plant life. No process plants yet been
designed to separate and dispose of the massive quantities of
waste—100,000 tons per year (based on 25 year life). Landfill
of the mixed wastes would conflict with sustainability policies.
Unlike waste from the nuclear programme, the complex materials
from solar panels do not decay.
6.4 To install 5,000,000 sets of panels in 13 years is
a rate of almost 400,000 per year, or 1,600 per working day. With
an average costs of £5,000, that would require expenditure
of £25 billion to generate only 2% of UK electricity. To
compare this scheme with a practical option, that same £25
billion could build a fleet of 25 1,200 MW PWRs, capable of supplying
some two thirds of UK electricity demand at secure prices for
60 years, with minimal greenhouse gases.
WAVE POWER
7.1 Wave power has been proposed as being well suited
for generating electricity in an island nation. The waves and
tides appear extremely dependable. Schemes have been investigated
with public funds since the 1970s, but have proved difficult to
scale up to industrial size. To generate 9 TWh per annum from
wave plants would require 2,570 MW of plant (assuming an optimistic
40% load factor).
7.2 The former government agency ETSU has predicted an
average energy potential of 1 MW per 30 m wave front around the
UK coasts. In March 2002, the Professional Engineer journal
included an item about Ocean Power Delivery (OPD) and their plant
called Pelamis, of which an example design 150 metres long would
produce 750 kW ie 1 MW per 200 metres. In April 2003, there was
an item in the same journal reporting a new design of plant operating
horizontally (Dragon wave power converter), claiming that a device
300 metres long could generate 7 MW. This equates to 1 MW per
45-metre wave front, a value between the other two.
7.3 Based on this third value, to replace a 2,000 MW
coal station like Radcliffe or Ironbridge would require wave machines
90 km long (2,570 MW would require 115 km). This makes no allowance
for spacing to permit access and ships to pass. If it weighed
100 tonne/metre, it would have a mass of nine millions tons. The
environmental implications of such massive structures are frightening.
Such structures are similar in size to oil platforms joined together.
Oil platforms however, can be built in docks on dry land and are
anchored with secure connections to the seabed. Wave machines
would have to be assembled out at sea and would be moving at the
mercy of the waves. The dangers of construction, operation and
maintenance are huge, but are not publicised when these schemes
are put forward.
7.4 Smaller plants have been tried. The 2 MW OSPREY wave
plant lasted two days off the coast of Scotland before being wrecked
in 1995. Similar destruction has been seen before. In the 1944
Normandy invasion, one of the two Mulberry harbours weighing about
1.5 M tons was buffeted and wrecked in a summer storm in the English
Channel after only 10 days use.
7.5 There are other ideas for using the energy in the
waves, using much smaller (a fraction of a MW) flow-stream turbines.
Three underwater turbines are to be installed on the seabed off
the coast of Alderney and Dorset. This is mentioned here, but
is covered fully in the next section.
TIDAL
The Severn Barrage scheme has been under review for several
decades and has been considered by the PIU. It would cost £12,000
million to build but would provide 7% of UK electricity (ca 25
TWh) and last for 120 years (Ref 7). The impact of this development
would be enormous and would affect up to perhaps 200 km2 of the
Severn estuary and catchment area.
There are other estuaries, but apart from the Mersey, the
others have relatively little potential, because of their area
or low hydraulic head. A river such as the Mersey or the Thames
with substantial shipping traffic would require complex and extensive
locks to maintain their port functions. The only major tidal power
scheme operating anywhere in Europe is in the Rance estuary in
France, where a barrage with 240 MW of turbines was completed
in 1966. This produces less than 1 TWh per year, with a load factor
up to 27%. To generate 9 TWh (without the Severn Barrage) would
require almost every large river in the UK to be used—Dee,
Morecambe Bay, Solway, Humber and Wash etc. Is it credible that
all the suitable tidal sites apart from the Severn could be planned,
designed, approved and constructed in a little over fifteen years?
The consequences of changing any one of these could be irreversible
environmental damage to substantial areas of the UK.
It has also to be recognised that although tidal power is
predictable, it is not continuous. Close to high and low tides,
no water is moving and no power is generated. As this will often
coincide with peak demand, other, more controllable power stations
will have to be retained.
Some underwater tidal flow turbines are being developed and
their output is more reliable than wind turbines. Devices currently
being tried have dimensions of 10 metre x 15 metre to produce
250 kW. Larger equipment may be developed, but it will require
5,000 to replace the Sizewell B nuclear station.
BIO FUELS
FOR TRANSPORT
There have been many proposals in the EU for the proportion
of transport fuels that are derived from natural grown species
to be increased to 5 or 10% of all liquid fuel consumed. DEFRA
have forecast that they will need 2.5-2.8 million tonnes of wheat
to achieve the 5% contribution to UK transport fuels, allowing
for waste in processing. DEFRA statistics show that average production
of barley in the UK between 2000-04 was 6.293 million tonnes,
from an average area during the same period of 1.112 million hectares.
Ie 5.5 tonnes per hectare.
To achieve the 5% contribution (assuming barley and wheat
crop at the same rate) will therefore require between 454,000
and 510,000 hectares. That is about twice the area of a small
English county. There are no such areas of new land, so other
products have to be sacrificed Either we will have to replace
500,000 hectares of other cultivation, or the people who received
the 2.5 million tons of wheat that has been exported in recent
years will see their food supply disappear into our petrol tanks.
THE 20% OF
ENERGY SUPPLIES
CONUNDRUM
The analysis above reveals the massive impact were renewables
to provide 20% of UK electricity supply. When faced with
the problem of generating 20% of energy, the problems become
much worse. Only about one third of the energy used in the UK
is used as electricity. The remainder is used in the form of natural
gas, coal or petroleum products. Twenty percent of UK energy
consumption is about 40 Mtoe ie about 450 TWh (1 Mtoe = 11.6
TWh). Most of the renewable energy sources can produce only electricity.
For renewable sources to produce 20% of energy, they have to produce
450 TWh of electricity, then the numbers discussed above would
have to be multiplied by about five. In fact renewables would
have to produce more electricity than all current fuels in the
present energy mix combined. They would in addition double the
total quantity of electricity used. The present electricity transmission
and distribution system would have to be strengthened through
massive investment. Equally important, electricity would have
to take over the role of natural gas and petroleum in many sectors.
This will require the wholesale reconstruction of much of basic
energy infrastructure.
13 June 2008
REFERENCES
1. Guardian newspaper, 3 June 2008.
2. The Energy White Paper. Our Energy Future—Creating
a Low Carbon Future Cm 5761, February 2003.
3. DTI Digest of UK Energy Statistics 2007 page
114.
4. The Energy Review. Cabinet Office PIU—February
2002.
5. New Civil Engineer Journal 5 February 1998.
6. Energy World, April 2007.
7. Prof Ian Fells CBE, FREng, FRSE, FInstE, FIChemE,
Institution of Mechanical Engineers Hawksley Memorial Lecture,
12 December 2001.
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