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BACKGROUND INFORMATION SUPPORTING OBJECTION TO WINBEG
Operational / Environmental / Technical non-viability
By Richard Hadden (An early-stage technology venture capitalist in Devon)
17th November 2004

The flaw with the WINBEG proposal is that it takes a green, local, sustainable technology and attempts to run it at the scale of traditional, centralised engineering (albeit only at MW, not GW scales).

Biogas systems are essentially small-scale, because bio-fuels are bulky and uneconomic to transport long distances, and overall energy efficiency and economic profit is greatest when heat output is sought as well as power generation, but heat cannot be transmitted any distance and must be consumed locally.

The need to maximise the heat output of biogas systems was noted in the 2003 Royal Commission on Environmental Pollution's Special Report on Biomass (I enclose a copy of Chapter 4), at paragraphs 4.18-4.22, and the need to minimise transport costs at paragraphs 4.23-4.26.

Fuel transport costs are particularly damaging to the business case for bio-fuels. Consequently, a plant is best sited where a volume of biofuel appropriate to its capacity is already concentrated, e.g. at paper mills (using wood waste or black liquor), saw mills (using wood waste) or sewage plants (using digested sewage). It is next to impossible for a large-scale bio-fuel plant to built and operated economically in a "naïve" site, where no bio-fuel is already concentrated.
Small accumulations of bio-fuel, e.g. farm slurry pits, can sustain small-scale schemes. However, there have been significant problems in designing biogas plants to produce electricity at small scales). The example given of BedZed in Surrey, an eco-development by the Peabody Trust, has experienced continuous reliability problems and has never reached the design output. This is part has been due to operating restrictions (non-continuous operation, to minimise noise pollution at night) required for planning consent.

A final transport hurdle for electricity-generating schemes is the distribution of the electricity. Again, small-scale schemes for local use will have minimal losses. Large-scale scheme designed to supply electricity to the national grid will, unless located close to markets, suffer transmission and distribution losses. Such losses are suffered by all generators, but they are more grievous when the energy is as expensive as bio-fuel electricity. WINBEG is miles from a population centre of any size, and there is no efficient transmission infrastructure over which to export its power.

Energy crops

The Royal Commission on Environmental Pollution Special Report on Biomass contains figures for the transport costs of different biomass crops by distance (Ch. 4 p.10, Table 4-I).
Taking the 50 mile (80km) radius catchment recommended by the WINBEG Biomass Fuel Assessment, we can, assuming a uniform distribution of crop growth in the catchment, calculate the mean collection distance weighted by growing area, i.e. the distance at which a perimeter encloses bounds half of the growing area. This distance is approximately 35 miles (56km).

At a distance of 56km, the Royal Commission Report finds a transport cost for miscanthus of c.£85/odt. We can therefore assume a mean transport cost for miscanthus within an 80km growing radius of £85/odt. This transport cost is significantly in excess of the recommended maximum total feedstock cost of £60/odt.

Indeed, at para. 4.34 the Royal Commission Report then quotes the work of Bauen, who has shown that the mean distance over which miscanthus can be economically transported is 20km, which corresponds to a maximum collection radius of 30km. Miscanthus has the smallest maximum economic radius of any energy crop.

This should be contrasted with the conclusion of the WINBEG Biomass Fuel Assessment, which concludes that the project is unsustainable with a maximum collection radius of 25 miles (40km) and will require a maximum collection distance of at least 50 miles (80km).

The minimum operationally viable collection radius for the energy crop tonnages required by WINBEG is over twice the maximum economically viable transport distance.

Miscanthus for the WINBEG plant can be sourced economically only within a 30km radius. By area, this is only 9/16 or 56.25% of the area of the 40km radius that the WINBEG Biomass Fuel Assessment rejected as too small. Using again the assumption of a uniform distribution of crop growth, we can reach two conclusions:

1. WINBEG will fail to source enough energy crops to meet its grant thresholds, or;
2. At least double the proportion of energy crops will need to be planted than WINBEG are projecting. A growing area half the area requires twice the proportion to be planted: a doubling in energy crop planting would represent a requirement within the 30km radius for 18% of arable and temporary grassland to be planted, or 29% of arable land.
Forestry Products

In the WINBEG Biomass Fuel Assessment (Table S9), it is projected that the plant will be fired in operating year 1 by forestry biomass (86,000 tonnes delivered weight), cellulosic fibres (28kt d.w.), sawmill co-product (8kt d.w.) and clean waste wood (6kt d.w.). By Year 6, the mix is projected to be forestry biomass (15kt d.w.), cellulosic fibres (28kt d.w.), sawmill co-product (8kt d.w.) and clean waste wood (6kt d.w.), with the substitution of 65,000 tonnes delivered weight of miscanthus for the balance of the forestry biomass.

The WINBEG Biomass Fuel Assessment admits that the bulk of forestry biomass is likely to be sourced from 7-14cm diameter roundwood, which is the only class of primary wood products for which there is not significant demand from existing non-fuel uses. The report recognises that sawn timber, while readily available, would be priced for manufacturing rather than fuel use, and would be a prohibitively expensive source of fuel. The report also projects availability in the entire South-West of <14cm diameter roundwood of only 50,000 tonnes per annum in the periods 2007-2011 and 2012-2012, falling to 45,000 tonnes p.a. in 2017-2021.

The Royal Commission Report concludes that forestry residues have a mean economic transport distance of between 30km and 50km, i.e. a maximum collection radius of between 42km (25 miles) and 70km (45 miles). The economic transport distance, although greater than that for miscanthus, is again considerably smaller than the collection radius required operationally by WINBEG to satisfy its forestry products biofuel requirement..

Even without regard to the economics of transport, the absolute demand of WINBEG far outstrips supply. Indeed, as the Biomass Fuel Assessment admits (para 3.3, p.71), imports of forestry products from other regions of the UK will be as important as sources within the South West, (let alone locally).

The WINBEG plant, by its own projections, will consume 170% of the small diameter roundwood in the South West in Year 1 (82,000 tonnes vs. 50,000), 190% in Year 2 and 124% in Year 3.

Although by Year 6 WINBEG will consume only 33% of the South West's supply of small roundwood, this decline assumes that the growth is miscanthus availability is as projected, an assumption the Biomass Fuel Assessment itself describes as ambitious.

Wood chip can also be used as well as roundwood as a biofuel, although it is also consumed in the manufacture of chipboard. Table 45 of the Biomass Fuel Assessment discloses annual availabilities of only 40 kt delivered weight of wood chip from processors and 35kt d.w. of wood chip and 52kt d.w. of small (<14cm diameter) roundwood from foresters (it is assumed, for the Table is silent, that these figures refer to the South West). There are therefore 127kt d.w. of all forestry biofuel in the South West. This falls to 92kt d.w. when offset against the 35kt tonnes d.w. of existing demand for wood chip from the Norbord chipboard plant in South Molton.

Moreover, the WINBEG plant is not the only consumer of wood biofuel. The Biomass Fuel Assessment itself lists three competing schemes in the South West, consuming in their initial phases up to 110,000 oven-dried tonnes of wood fuel, i.e. closer to 200,000 tonnes delivered weight. Their steady state consumption, i.e. when energy crop substitutes are available, is projected to be up to 45,000 oven-dried tonnes or up to 90,000 tonnes delivered weight.

Including WINBEG, total peak demand in the South West for wood biofuel could be 286,000 tonnes delivered weight p.a., against an availability of 92,000 tonnes d.w. p.a., with a long-term demand of 100,000 tonnes d.w. p.a. against 87,000 tonnes d.w. p.a..

WINBEG's consumption of forest products as biofuels is unsustainable, because it relies on imports from outside the South West; doubly uneconomic, given the costs of transport and the likely price pressures in a market in 300% over-demand; and extremely insecure, given the historically slow growth in energy crop production and the admitted insufficient local supply of biofuels. At its worst, it may divert materials away from established industries, e.g. wood chip from NorBord at South Molton.
Distance from markets

North Devon is recognised as the last zone of rural tranquillity in Southern England: it has no heavy industry, no major urban centres and a thinly dispersed rural population. Consequently, energy from the power station will need to be transmitted wide and far to reach consumers. Energy distribution costs are structurally higher than the national average, and this is not overcome by providing more expensive and experimental forms of energy.

The efficiency of power lines increases with voltage and decreases with the square of distance. The low population density of the area will require transmission/distribution of energy over long distances to reach consumers, and energy losses will be structurally higher than if the plant had been sited near consumers (e.g. Plymouth).
Energy will only reach the national grid efficiently if a high-voltage transmission line is built to Okehampton (with the environmental impact discussed below). Average transmission losses for England & Wales are 1-2% (National Grid figures).

However, the line proposed, 132kV, does not qualify as a transmission line by standards in England and Wales. It is a distribution line, with higher attendant losses. Average distribution losses for the South-western region are 7.9% (OFGEM report, January 2003, Table 4.1).

Any injection of power into the immediate local distribution network at Winkleigh will be over even lower voltage distribution lines, and therefore suffer higher transmission losses.

Total power losses in transit will exceed 10%.
CO2 offset of transportation

As well as its direct impact on fuel costs, the excessive transportation requirement of WINBEG reduces the benefit of its renewable energy.

Working with the recommended Biomass Fuel Assessment collection radius of 50 miles, we can calculate an area-weighted mean journey for each fuel load of 35 miles. Given the traditional nature of the roads in the area, let us assume an average speed of 35 mph. Each journey therefore takes 1h. Using the reports figure of c.24 deliveries per day, or 48 lorry movements, we can calculate that 48 lorry hours are required per day. Taking a modern lorry engine, e.g. the "Scania 16l", and generously assuming that it runs at 60% efficiency (not realistic for a production diesel engine) at its maximum power output of 368KW, 48 continuous lorry hours will consume 368*48/0.6 = 29440kWh/day = 29MWh/day.

WINBEG's gross maximum output is 552MWh/day. WINBEG's projected output is of 90% of capacity, i.e. 497MWh/day. Adjusted for transmission losses of 10% (see above), effective output will be 447MWh/day. Although these 447MWh/day will be carbon-neutral, they will have absorbed 29MWh of fossil fuel. The assumptions of continuous efficient operation, least-distance routes, mean transport distance and optimally full loads are all very generous and actual consumption is likely to be significantly higher. WINBEG will therefore consume fossil fuel energy of at least 7% of its effective output.
Technical issues

The technology has not been run for any significant length of time. The Vermont McNeil power station installation was a demonstration of a little over 200 hours of operation, of which the longest continuous burst was 63h. The Vermont plant was significantly smaller in scale, as well.

Biogas / black liquor systems have one major important technical issue to solve: preventing the combustion nozzles etc. from clogging up and the refractory lining of the combustion chamber being damaged by the deposition of impurities in the gas being burned, which include organic tars, inorganic acids and minerals such as silicates. Everything else about the system is just standard thermal power engineering and/or chemical engineering. The trick is designing it to cope with the dirty fuel, compared with natural gas etc. without raising maintenance or construction costs through the roof.

There is no detailed discussion in the technical evaluation of the essential operating parameters of the proposed process. In particular, while there is a discussion of the likely composition of the miscanthus fuel in the Biomass Fuel Assessment, there is no complementary discussion of the input requirements / tolerances of the system that will burn it.

This is area where these technologies suffer the greatest risk in scaling them up. What works fine as a mass or energy balance equation in a lab or a short (200 hour) demo suddenly falls apart under real conditions with variable real crops and long continuous operation. Clogging up in operation was the reason that the ARBRE plant failed.

Without a thorough, warts-and-all discussion of the technical issues that have been encountered and which are predicted for this, the largest installation and the only one to date intended for commercial use (the Vermont trial was non-commercial), it is hard to believe there is any substance to the claims that the technology will work.

Experience, as a technology venture capitalist, suggest that it won't, and that it will cost more time and more money than ever thought possible to discover this, let alone fix it.