Short statement
From Energy-Experts
This started out, first version as a 2000 word document to go in Professor David Elliots Newsletter Renew, which deals with Renewable Energy:
Claverton (short) statement
Claverton Energy Briefing
The Claverton Energy Group is a network of nearly 200 energy practitioners and academics committed to a sustainable energy policy for the UK. The group has organised three conferences in Claverton, Bath, during 2007and 2008.
This article represents a selected summary of views so far. Intensive open discussion continues electronically. A book is planned. Experts have provided access to their published studies including quantitative modelling. We judge the latter is essential for estimating ‘renewables energy’ contributions in a sustainable future. Claverton also receives support from many with international knowledge; for example, a manager experienced in the Danish electricity grid integration of wind power and combined heat and power (CHP). Other authoritative sources are referred to in the text.
A matter of urgency
At the November 2007 European Offshore Wind Conference; Malcolm Wicks UK Energy Minister, said: “energy security is becoming a key component of national security when you look at current geopolitical risks.” He recognised the twin challenges of climate change and energy security. Claverton agrees: UK domestic reserves of coal, oil and gas are shrinking rapidly to insignificance. In a few years almost all fuel will be imported. Even in the preferred context of pan-EU security, the UK needs urgently to harness domestic renewable resources.
Globally, the more fossil fuel that remains in the ground the better climate change might be controlled and future industry secured[i]. Security of supply however must not be neglected whilst establishing carbon saving. A global ‘energy gap’ of 13.5M barrels per day of oil (current production ~86mbpd) is predicted in the next 7 years (IEA[ii]), and the end of the fossil gas era looms for the next generation. Claverton also draws attention to massive downward revisions in estimates of coal[iii] and the urgent need for transparent data and for an ongoing watch on these critical issues as they affect internationally available supplies.
We have at times been distracted by a plethora of ‘future’ technologies, but some must be, frankly, relegated to a ‘wish list’. Others need more R&D before they can be properly evaluated let alone make a significant contribution. Sometimes simple calculations show that certain technologies as they stand, though they might make money, can only provide marginal substitutions for fossil fuels. Given the importance of state policy, attempts by competing or conspiring sectoral interests to capture policy could distort UK industry and shut out investment in key ‘green’ technologies. We are alarmed for the UK and think it most unlikely that we will enjoy the luxury of gradual change to a ‘green future’. We insist on promotion of ‘energy-saving’ and the most readily developed of the candidate renewable primary sources of energy.
Wind Power could supply 23% of EU electricity by 2030[iv]. The interconnected wider EU context for utilising wind is important, and given the UK’s large offshore potential and BERR[v] recent proposal for a UK 33GW installed nominal capacity by 2020, Claverton urges a maximised UK drive to help exceed EWEA[vi] lower estimates of 20-40GW for accumulated EU offshore wind by 2020, aiming for 50GW or higher. We remember, however, these initial nominal capacities would deliver little more overall than 4% of EU electricity demand, equivalent to half that currently provided by large hydro, and, would not compensate for serious early ‘energy gaps’.
Preliminary quantitative modelling[vii], based on hourly UK wind and electricity demand data suggests that a system in which 95% of the energy is renewable, (mostly wind with significant marine and solar contributions) could supply electricity reliably hour by hour over the whole year if storage, trade (import/export interconnection) and optional generation (including localised generation) were deployed alongside demand management. We need, however, to include further security criteria. Even when wind generation exceeds demand for electricity, a number of large synchronous generators must be connected to the grid at any time in order to maintain system stability. Although it is very challenging to develop a future power system with a high share of intermittent generation, we consider successful transition is possible if radical restructuring takes place in due time. A strong European primary super grid and efficient trading arrangements will facilitate international exchange and regulation of power. (We are encouraged that transmission losses for advanced UHVDC are ~3% per 1000 Km). Distributed generation can support power balance. There is potential for larger batteries and pumped storage, and “demand side participation” by multiple ‘micro’ thermal / refrigeration and battery stores, all contributing to peak-lopping and smoothing imbalances. We envisage an expanded ‘optional’ role for diesel generators that are on standby for other purposes but are available to back up the grid (~20GW UK potential), and a future role for localised combined heat and power CHP. Marine ‘renewables’, also will help by providing fluctuating but highly predictable and flexibly managed, complementary sources of supply.
Wave energy converters are currently in demonstration in UK, EU, and elsewhere but suffer from very high cost estimates compared with other key renewables. Even with optimistic cost learning the UK resource appears constrained. For example, with Atlantic power densities of ≥55kW/m, ~19,000 ‘pelamis’ type units (40 per 2.1km) per 1000km coastline would yield 54TWh/year. Present UK electricity output totals ~400TWh/y.
Tidal current turbines are in prototype demonstration and advanced planning. The high energy density of currents and the less dynamically stressed underwater situation provide much lower estimates of current start-up costs compared with wave. An upward revision of the resource[viii], suggests a realistic 25 GW output on average contributing ~220TWh/y, or more than half present total UK electricity production. As a practical accessible resource this bears comparison with very large scale offshore wind.
Tidal lagoons (with potential for pumped storage): Their environmental impact should be much less, and output more evenly-distributed than a Barrage. Potential to double as pumped storage compares favourably with a profitable hillside back-up solution for nuclear power (Dinorwig, Wales). Theoretically, pumped storage could turn 1.8GW of variable wind power into 1.9GW of steady power: a round-trip efficiency of 105% compared with Dinorwig 75%[ix]. Large sites (The Wash and Blackpool could each offer 10km by10km), with a combined average output of more than 800MW, should provide 1-2 percent of present UK electricity output at possibly lower cost than nuclear. Modest financial risks suggest a ‘no-regrets’ start.
Flow Batteries already exist as long-life low-maintenance Vanadium Redox Batteries (VRB) for smoothing output from localised wind farms with ‘round-trip’ efficiencies of 65-75%. There is potential for scaling up the modular technology to >GW capacity attached to wider grids.
Energy saving in buildings: Arguments are overwhelmingly in favour of insulation, improved draught and ventilation control and heat-recovery in existing buildings, and sharply raised standards of ‘new-build’. Many research programmes show that it is technologically and economically feasible to at least halve the carbon emissions (presently 27% of the UK's total) from existing UK housing with much scope for deploying the kinds of loans and subsidies used successfully elsewhere, for example in Germany[x]. Both immediate gains in household and business utility and future national security demand an industry achieving higher standards of retrofit.
‘Zero Carbon Homes’: Space heating and hot water targets are technologically achievable in new-build (~30% of housing by 2050) but first generation micro-wind electricity turbines do not have sufficient performance and the wind resource is very poor in most urban situations. Solar PV, although expensive at present, is in rapid expansion (4GW nominal already in EU), and hopes for newer technology promise wider uptake in UK. A million roofs in the London climate could yield 3.4TWh/year[xi].
Biomass and biofuel: The UK cannot expect to grow more than a small fraction of the energy needed to substitute for existing uses of oil, coal or gas. This means large imports if bio-energy is taken seriously and very large imports to serve current liquid fuel bio-refineries. Energy returns on energy invested (EROEI) ratio is very poor for first-generation UK ethanol and maximum areas sown to Oil Seed Rape could only substitute perhaps ~6% of current diesel[xii]. There is potential for rather more home-grown dry biomass for power stations, but realistic amounts do not come close. The efficient Elephant Grass (Miscanthus) could provide 4 – 6.2t coal equivalent per hectare per year[xiii], whereas UK imports each year a rising 50Mt of coal for ~27% of electricity. The UK cultivated area, including ~6.8Mha grass, totals only 12.1Mha, with further ~5Mha rough grazing and ~2.8Mha forest. Although we support the use of bio-wastes and continuing R&D into ligno/cellulose conversion to ethanol, and envisage a future when CHP uses UK-grown biomass to heat ‘low-carbon’ buildings, intense competition seems inevitable globally with food and other essential cropping. We support calls for much better quantitative studies of EROEI, and evaluation of dangerous net carbon emissions and other ecological destruction arising from global production.
Combined Heat and Power and District (DH) / Community Heating (CH): The case for CHP linked to DH/CH seems overwhelming, not least as a rapid way of reducing UK primary energy demand and securing utility. With integrated planning, CHP/DH can make best use of gas and we envisage economically viable retrofit to existing buildings. Potential serious competition from domestic gas-fired micro-CHP seems unlikely if the very modest ‘carbon savings’ seen so far from micro-CHP are confirmed. Similarly, although future heat saving in buildings (perhaps averaging 50%) seems unlikely to detract from viability of DH/CH schemes, intensive quantitative modelling studies are required, particularly for the important suggestion[xiv], that programmes for converting CCGT power stations to CHP could reduce the ‘carbon footprint’ of existing housing at least as effectively and fast as parallel ‘insulation’ programmes. DEFRA[xv] calculates a possible 2GWe electrical capacity for London out of a UK maximum total of 36.5GWe. Transmission losses need not prevent distant heat from a very large provider, and Barking’s gas-fired power station near London would provide utility well into the declining years of the gas era. Additionally we see more flexible, multiple, 500MW initially gas-fuelled CHP/DH, sited probably at low-voltage electricity grid substations. We imagine optimised systems where this CHP and superior building performance allow a transition from gas to biomass, and where DH thermal storage (perhaps combined with heat pumps) or other storage that could include hydrogen from electrolysis combined with fuel cells, helps make best use of wind energy.
Transport: Claverton is positive about maintaining essential economic utility of ground transport in a future sustainable economy. We look forward to an expansion of electrical transport, especially trains, trams and trolleys. Despite the electrical motor’s high efficiency, the large thermal inefficiency of present electrical generation means that overall efficiency is especially low in existing battery-driven all-electric vehicles. Similarly, although there are promising prototypes of advanced batteries, and we see an attractive prospect of millions of recharging transport batteries helping buffer fluctuations in wind power, large scale manufacture is yet to be proved.
Despite their rapidly growing use, biofuels are likely to be a severely limited resource, as already discussed, even with promises of “rivers of ethanol issuing from Brazil”[xvi].
Nuclear power and coal: Claverton tends to play down both nuclear power and coal as solutions to energy security. Nuclear power suffers from very unfavourable geopolitical and security limitations with likely future fuel constraints, and it is not certain that UK could obtain during coming critical decades more than a small share of any realistic expansion of the world fleet. For example, MIT[xvii] projects to 2050 a limited ~1100GW with ~30% in the USA. While climate change makes burning coal without carbon capture increasingly unjustifiable, this not yet mature technology is projected to need at least 20-30 per cent extra coal to be burned. On balance, with domestic production dropping rapidly to insignificance, we judge the UK is best advised to develop an exit strategy and move on from coal.
Desert Solar CSP: Success over two decades of USA prototypes for thermal generation of electricity has led to recent construction in EU (Spain) and USA, and designs for heat storage that could extend the daily generation period. Proposals suggest 25% of EU electricity imported from North Africa, transmitted via UHVDC, to the ‘mutual benefit’ of both regions. The potential supply is comparable with that from EU wind resources.
Incentives, risks and regulation: None of our experts think that UK/EU yet has incentives or regulation adequate to usher in a new era or cope with energy insecurity. While not seeing a need to dismantle UK and EU policy instruments, including emissions trading, the need for political will and adjustment is obvious. Desired outcomes should be clearly determined and signalled to competitive markets and incentives put in place, but it should be also made clear that progress will be rigorously monitored and incentives adjusted when necessary. Investment in ‘capital-heavy’ but ‘fuel-light’ renewables needs continuing support in the face of more easily financed, but ‘fuel-heavy’, fossil energy infrastructure. The success of Germany, Denmark, Spain and Portugal with ‘feed-in tariffs’ for renewables electricity is obvious. We recommend the UK introduces ‘Renewables Energy Feed In Tariff’ (REFIT), to guarantee long term fixed prices more cost-effectively than the Renewables Obligation (RO). Pragmatically, for consistency it could make sense to retain the RO as a shell and to use Non Fossil Purchasing Agency Limited (NFPA) to harmonise the two arrangements.
[i] Rutledge, CALTECH, 2007, http://rutledge.caltech.edu/
[ii] IEA 2007, FT interview with Fatih Birol, registration required, http://www.ft.com/cms/s/0/3c8940ca-8d46-11dc-a398-0000779fd2ac.html?nclick_check=1
[iii] Energy Watch, 2007, http://www.energywatchgroup.org
[iv] EWET platform 2007 http://www.windplatform.eu/
[v] BERR, December 2007 http://www.gnn.gov.uk/environment/fullDetail.asp?ReleaseID=337237&NewsAreaID=2
[vi] EWEA, 2007 http://www.ewea.org/fileadmin/ewea_documents/images/publications/offshore_report/ewea-offshore_report.pdf
[vii] Barrett, University College 2006 www.cbes.ucl.ac.uk/projects/EnergyReview.htm
[viii] Mackay 2007a following Salter 2005, http://www.inference.phy.cam.ac.uk/sustainable/book/tex/TideEstimate.pdf
[ix] Mackay 2007b http://www.inference.phy.cam.ac.uk/sustainable/book/tex/Lagoons.pdf
[x] House of Commons EAC 5th Report 2006 http://www.parliament.uk/parliamentary_committees/environmental_audit_committee.cfm
[xi] Banfill & Peacock, Building Research & Information, 35, (4) July 2007, 426 - 436
[xii] Scottish example, SAC Edinburgh 2005 http://www.angus.gov.uk/ac/documents/sacreport.pdf
[xiii] DEFRA July 2007 www.defra.gov.uk/erdp/pdfs/ecs/miscanthus-guide.pdf
[xiv] Orchard Partners London Ltd., admin@orchardpartners.co.uk
[xv] DEFRA Analysis October 2007 www.defra.gov.uk/environment/climatechange/uk/energy/chp/pdf/potential-report.pdf
[xvi] Brazil’s Agriculture Minister 2006 agecon-trec.ifas.ufl.edu/documents/sugarAug1.pdf
[xvii] Massachusetts Institute of Technology, 2003 http://web.mit.edu/nuclearpower/
See also: Essays about Claverton
