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The debate over how much back-up capacity is needed to balance wind variations continues. Everyone agrees you need some, but some say you need 100% and that, as a result, wind power won't save many or, even any, emissions, net. See for example: http://environmentalresearchweb.org/blog/2011/11/does-wind-power-reduce-carbon.html

There is, in this debate, usually a confusion between, firstly, short term balancing (which is done all the time, even without variable wind on the grid) to deal with occasional unexpected plant or grid trip-outs and the daily demand variations, using frequency adjustments and by winding-up power from 'spinning reserve' plants; and, secondly, longer term possibly larger and longer loss of power issues, when you may need to crank up extra plant to meet gaps, calling on the built-in extra plant margin that grids have for this purpose.

For the moment, most grids can cope with the amount of wind linked in relatively easily, as many reports have indicated. The latest, 'Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations', produced by Alstrom for the US Dept of Energy, offers first- hand perspectives on how variable energy sources, including wind, actually impact grid operations. It finds that the ability to forecast variable energy output is vital to integrating variable energy. It also describes several decision support tools that are currently used by grid operators. http://energy.gov/articles/new-report- integrating-variable-wind-energy-grid

But some extra fast start-up back-up, and maybe extra marginal gas plant, may be needed as the share of variable renewables grows. Key roles can also be played by other grid-balancing strategies, e.g. smart-grid interactive demand management and importing power from other countries via HVDC supergrids.

Alstrom's US report does note that upgrading grid transmission links is a key long-term requirement - not least to deal with the perhaps more relevant problem of how to deal with excess power from wind and other variable renewables.

All that said, you will still find substantial contrarian assertions (e.g. from the US energy collective.com and the North American Platform against Wind Power: www.na-paw.org) that the variability of wind is an unresolvable issue. Similar lines of attack have been adopted by some UK centre-right think tanks, most recently by CIVITAS.

Much is made of the large and rapid swings from full power to low power that can occur, despite the fact that grids already deal with large demand swings daily. True, the existing swings are usually predictable, which is why the US Alstrom report looks to improved wind forecasting. But, while there's no one solution, given smart grids/DSM and storage plus supergrid imports, it should be possible to balance even large variations- though it may be harder in the US, where cross national grid links are weaker and there's less gas/CCGT, although of course shale gas may change that.

Back in the UK, we have a good well integrated grid system and last year a Poyry report for the Committee of Climate Change spelt out how it, and some upgrades and extensions, could help us balance some 'stretching but feasible' scenarios with high levels of renewables (reaching up to 94% in the Max scenario).

They found that 'the electricity system was able to accommodate these high levels of renewable generation whilst complying with the specified constraints on emissions and security of supply. However, this was at the cost of shedding low variable cost generation and construction of new peaking capacity; predominantly in the two 2050 scenarios and Max scenario'.

Shedding power (or 'curtailing' excess output) is wasteful, but building new low cost gas-fired capacity is relatively cheap, and they say, not urgent 'Construction of peaking plant is not required until after 2030 in either the VeryHigh or the High scenario'.

Overall they say 'Sufficient technical resource appears to be available to deliver very high levels of renewable penetration', but if offshore wind then dominates, diversity is reduced making grid balancing harder. So they are keen on a wider range of renewables being used.

So how robust is their projected future renewables-based system? They report that their scenarios were also tested against 'more extreme weather conditions, as defined as increased frequency of low wind periods ('lulls') and greater variability of wind output.'

They say 'In our (very) high renewable scenarios, we found that there is relatively little difference between the level of security of supply...in an average weather year and from the level in one of our extreme weather years'. But 'CO2 emissions increase in the year with more lulls because fossil fuel plants run at higher load factors to compensate for lower wind output. In contrast, there is a (slightly) higher average annual load factor for wind in the more variable wind year. This leads to lower emissions, particularly in 2030.'

For the moment there should be no major problems, but we will need to act later; 'The closure of unabated gas plants will reduce generation flexibility by 2050': while in 2030, the electricity system is able to accommodate high levels of renewable penetration 'in 2050, around 40TWh of low variable cost generation is shed in the High and Very High scenarios, with a need for new peaking capacity of 6GW and 10GW respectively'.

The situation is even worse in the Max scenario when 'shedding increases to 120TWh a year, and 21GW of new peaking capacity is required to meet the desired level of security of supply. This is despite an assumed increase in demand-side flexibility and an expansion of interconnection capacity between 2030 and 2050 (and between 2050 and the Max scenario).'

So in addition to grid extensions and demand side management, after 2030 you also more peaking plant., although they add 'a more diverse renewables mix helps the system to accommodate high renewables. Increasing the deployment of solar and tidal range (and reducing offshore wind deployment) in the High scenario leads to a big fall in the amount of shedding and required new capacity build in 2050.'

They say that, although it in basically inflexible, nuclear might also play a role: 'despite the increase in shedding, construction of nuclear capacity is still cost-effective given the assumed set of fuel and carbon prices and generation costs', but they add, 'alternatively, interconnectors could be used to provide GB with access to a more diverse renewables mix in Europe'.

We do seem to have plenty of options. And Pyorys analysis does seem to be an answer to all those contrarians who say renwables can't do it , though some still say ramp-up rates will be high, and hard for existing peaking plant to cope with. The debate continues

Pyory report 'Analysing technical constraints on renewable generation to 2050', to the CCC, March 2011

Energy systems will increasingly have to cope with variable supply inputs, as more renewables come on the grid. The grid system already has to deal with variable demand patterns, and it is usually argued that the strategies used to do that can be extended to also deal with variable supply. So, for example, in addition to short term frequency adjustments, variable wind can be backed up using power from the flexible fast start up gas turbines, or plants kept on spinning reserves, that normally deal with demand peaks or sudden plant shut downs. But there are limits (maybe above a 20% input) to how much variable supply can be accommodated in this and similar ways, and it is often suggested that more energy storage will be needed.

There are some new short to medium term storage options emerging, which can buffer variable outputs from wind etc, for example various types of flow battery, liquid air storage and even conversion to hydrogen gas via electrolysis, but the problems with storage is that it's inefficient and expensive. Much more so than just adding more cheap backup capacity. So some say the best type of storage is natural gas, stored ready for use when power is needed from back up plants. Using that of course incurs an emission penalty. The next best option, and one that is 100% carbon free, is pumped hydro storage, but there is not much of that available in the UK.

Several other counties in the EU, do however have very large hydro capacities (there is 30GW in Norway alone) and some of these reservoirs are now being converted to pumped storage; e.g. Germany's Thuringia State has identified 13 potential sites, including 3 existing dams, for constructing pumped- storage plants that would total 5,130 MW.

However, even without pumped storage, hydro reservoirs can be used to help balance variable renewables by simply delaying their output when there is plenty of power - a head of water in kept back until extra power is needed. But that does not help with what is probably going to be a bigger issue than occasional low power availability from wind - the regular excess power that wind, and also solar, wave and tidal power, will produce when demand is low.

A possible solution to that is transmission to locations where there are shortages: even if it means long distance transmission. You would need that anyway to link to hydro around the EU. As well as being used to balance variable renewables around the EU and for liking to offshore wind in the North Sea and hydro across the continent, High Voltage Direct Current (HVDC) links could also be used for importing solar derived power from the desert areas of North Africa and the Middle East. HVDC supergrid grids can do that with low losses (2-3% /1000km) compared with conventional HVAC grid (up to 10%/1000km).

HVDC has its disadvantages- you have to have expensive transformers/invertors to upload AC from generators and to download DC to AC end-users (assuming that generation and use can't actually be done with DC), and so it's best for long distance interconnections. AC is best locally and perhaps also regionally. Interestingly, while backing HVDC for longer distance links, the SRU, Germany's Advisory Council on the Environment, has suggested that, to avoid the problem with local uplinks, there could be a lower frequency 16.7 Hz overlay AC grid in Europe, at 500 kV. They say that would 'reduce the ratio between line length resistance and frequency, which would represent a threefold reduction relative today's 50 Hz frequency'.

All the foregoing is on the supply side. What about managing demand? There is much interest in 'smart demand' system , e.g. time-shifting electricity use by incentivising customers to run their energy consumption appliances off-peak, through time-of-use tariffs delivered through smart meters. More aggressively, some loads than are not sensitive to short interruptions can be turned off remotely for a while.

A study by Delta says that shaving system 'peaks' reduces the need for peaking plants which are often less efficient and/or use more polluting fuels, to run; it can also enable delay or prevention of the need for investment in new network capacity. And it can fill system 'valleys' - helping to increase and optimise the operation of lower carbon baseload plant. Based on studies by the Brattle Group they suggest that demand response across all sectors (through the use of time-of-use tariffs) with a 43% take up, can shift 5% of the system peak to off-peak times. Delta: http://www.delta-ee.com/ www.brattle.com/_documents/UploadLibrary/Upload578.pdf

Smart grids can also offer other benefits, including diagnostic checks on the performance of heating & ventilation systems, heat pumps, refrigerators, etc. with savings of up to 20% being claimed in some cases. In addition, providing on line 'smart meter' information to consumers about their energy use, could help them cut out waste, change their lifestyles and/ or lead them to invest in more efficient systems.

So there are a range options on both the supply and demand side. They are not the only ones. For example, the emphasis above has been on electricity production and management, but there are also heat production and storage options. Heat is much easier to store than electricity and heat stores could be used as a way to balance variable renewables.

Whichever route is taken some of these options will take longer to deploy than others, and all will be relativelycostly. But then so will continuing to relay on fossil fuels- in economic and environmental terms. We have to shift away from them.

The key issue then is - will the new supply and demand management options be enough to allow variable renewables to expand to the 50% and even 100% that some say is possible at some point?

Optimists, including NGOs like Greenpeace and WWF, but also many energy analysts, say yes. For example see National Grids recent scenarios, which include a version with up to 67 GW of installed offshore wind generation capacity by 2030. www.nationalgrid.com/uk/Electricity/ODIS/CurrentStatement/ and on a wider scale, the new roadmap to 2030 from the European Climate Foundation: www.roadmap2050.eu/pp2030

Pessimists, including some from traditional engineering and/or conservative political backgrounds, say no, renewables can't be used on a wide scale, but offer few alternatives except maybe nuclear and /or Shale Gas with Carbon Capture and Storage. For a recent example see the report published by the Adam Smith Institute: www.adamsmith.org

It will be interesting to see which view prevails.

Both the optimist and pessimists seem to be listened to by government and both are also being backed by corporate money to some extent, whether its EDF and EON being willing to invest in nuclear, or Siemens, Vestas, GE and Mitsubishi investing in off shore wind turbine manufacturing plants in the UK . Some think you can and should do both, and also CCS, but given limited resources, it may be hard to do that well, and there are operational conflicts between basically inflexible nuclear and variable renewables. We may need to make choices.

In my next Blog I'll look in a bit more detail at some off the arguments on grid balancing in relation to wind.

'Only a system with its base-load provided by nuclear power, supplemented by gas for peak demand, and retaining the existing wind investment, can possibly supply the UK long-term with the huge amounts of secure and reliable, predominantly electrical energy, it needs. To actually achieve a changeover to a largely non-fossil fuel economy without wreaking catastrophe on our industries, the targets set by the Climate Change Act 2008 will have to be pushed back no matter whatever combination of electricity generating technologies is built'. So says Prof. Stephen Bush from Manchester University, writing, with David MacDonald, in The Chemical Engineer, ICE's magazine, last Oct.

This conclusion is reached in part by wheeling in the standard arguments about the low energy intensity and high variability of renewables and consequent large land areas needed. Is that so? It's certainly a view widely promoted these days in the media. See my earlier ( New Year) Blog. http://environmentalresearchweb.org/blog/2011/12/new-year-wish--a-more-balanced.html

As I pointed out there, it's been argued that PV can mostly be on roof-tops, so there is no extra land-use. With offshore wind, the land-use issue disappears, but variability is certainly an issue. The ICE article says 'to store a week's supply of electricity from the current 3,226 MW grid-connected wind capacity working at the annual average 25% load factor would require 4.5m m3 of hydrogen stored at 10 bar, or a lithium-ion battery stack 100 m2 by 34 m high. Extrapolated ten times to the 32 GW of wind capacity proposed in National Grid's Gone Green scheme, it can be seen that this buffer storage concept to use wind power on this scale is another blind alley'

Whoever said we needed to be able to store a full weeks wind output? Some storage would be helpful, especially pumped hydro, but when there are local UK wind shortfalls, in addition to all the usual backup available from the rest of the grid system, what about importing power via a super-grid, shifting demand peaks by interactive load management, and using biomass-fired backup? It's certainly going to be challenging to meet the targets, but that's what targets are for- to set the pace.

However some say it will cost a lot. In Fraunhofer Institutes Working Paper S7/2007 on Sustainability and Innovation, Frank Sensfuß, Mario Ragwitz and Massimo Genoese look at the so-called 'Merit-order' effect, offering a detailed analysis of the effect of renewable electricity generation on spot market prices in Germany. It's argued that when there is a lot of wind energy on the system, less generation is required from other sources. This cuts wholesale electricity prices, which reduces (non-wind) generator profits, but benefits consumers. It's claimed that the overall savings is greater than the subsidy paid for wind. So the net cost of supporting wind can be negative. See also Awerbuch, S. and M. Berger, 2003 'Applying Portfolio Theory to EU Electricity Planning and Policy Making', OECD/IEA, which comes to similar conclusions. www.awerbuch.com/shimonpages/shimondocs/iea-portfolio.pdf

That is not to say the initial capital cost will not be significant. The new report 'Positive Energy' from WWF, claims that renewable sources of energy could meet up to 90% of the UK's electricity demand by 2030, but it notes that this may not be achievable in that time frame. Based on a series of scenarios produced by consultants GL Garrad Hassan, it concludes that the amount of renewable capacity the UK can build is determined by economic constraints - not available resources. Garrard Hassan assume that it's economic to supply around 60% of demand from renewables. WWF say that going beyond 60% depends on whether there's a market in other countries for the excess electricity the UK would generate at times of high renewable production/low demand. Therefore, given uncertainty over future markets, in the core scenarios, they do not assume a European market for UK renewable power, and they only have a 3GW supergrid interconnection.

By contrast, in the 'stretch' scenarios, it is assumed that interconnection creates a European market for the UK's excess power, and that it becomes economic to build much more renewable capacity in the UK- with up to a 35GW supergrid interconnection. In addition to providing an export option, that provides a balancing option for when weather conditions across the country mean little power from renewable generation (like wind power). Otherwise that has to be done mostly using gas plant. However they say that, even then, decarbonisation targets could still be reached, with an ambitious roll out of CCS on a significant proportion of the UK's gas capacity, but with CCS plant run at 80% of their load factor (capacity) and non CCS plant run at considerably lower load factors. Clearly though they would prefer a high levels of interconnection.

WWF says that the government must give investors enough certainty to be willing to make large-scale investments necessary in the UK renewables supply chain. It's therefore called on the government to commit to a target of getting at least 60% of UK electricity from renewables by 2030. .

'Positive Energy: how renewable electricity can transform the UK by 2030' http://assets.wwf.org.uk/downloads/positiveenergyfinal_designed.pdf

Broadening the view to cover the whole EU, Power Perspectives 2030, phase 2 of the groundbreaking Roadmap 2050 report from the European Climate Foundation, looks at the key steps to power sector decarbonisation across the EU for the next two decades. It says that while the existing energy policy framework to 2020 represents an adequate first step towards the EU 2050 emission reduction goals, the decarbonisation process will need to accelerate significantly in the decade 2020-2030.

In what it labels an "on track" scenario, based on the EU managing fully to implement its plans up to 2020, and assuming there are projects in 2030 in line with targeted emissions cuts, it anticipates a power mix in 2030 made up of 50% renewable energy. The rest would include 34% fossil fuels, plus a further 8% abated by CCS, 17% by nuclear. After that could come a push to get to near 100% from renewables by 2050, as outlined in their original report, with nuclear phased out.

The ECF led the project with McKinsey, E3G, KEMA, and Imperial College: www.roadmap2050.eu/pp2030

The European Commission has come up with something similar in its new 2050 Roadmap, which aims to get to virtually carbon free electricity, and an overall cut in emissions of 80-95%, by 2050. So the UK will not be alone if it perseveres in seeking radical change.

In some industries, such as steel and aluminium production, energy is the main cost, so it is not surprising that, since it is increasingly expensive, efforts have been made to use it more efficiently. But in most industries, cost savings are possible, and have been made by careful attention to waste, new technology and improved process control. As well as saving money, using conventional fuels more efficiently can, by reducing the amount of energy needed, also reduce greenhouse gas emissions. The UK Carbon Trust's Industrial Energy Efficiency Accelerator is looking at fourteen industry sectors, and has identified energy, carbon and cost savings typically averaging 25-30%.

Energy supply companies are also gradually switching over to using renewables sources, so that the carbon content of the energy used by industry is falling. However some industries have adopted a more radical approach - actually generating green power themselves.

For example, Ford has installed 3 large 1.8MW wind turbines at its diesel engine plant in Dagenham, NE of London, supplied by green energy company Ecotricity. Ford say that 'Green power from Ecotricity is saving Ford money and there are huge environmental benefits too. Thousands of tonnes of power station emissions are saved by switching our electricity source for the Dagenham Diesel Centre to wind power' .

Ecotricity has also installed a series of 3 wind turbines at Avonmouth Docks near Bristol
and at a Sainsbury warehouse depot in East Kilbride in Scotland. Sainsbury seem very pleased with this involvement with wind power : 'With this project, Ecotricity has helped us to meet our environmental goals and our energy needs. We have this fantastic state-of-the-art wind turbine on our site, which not only looks great but is providing almost half the depot's electricity, with no carbon emissions and at a cheaper price'.

These are examples of what Ecotricity calls Merchant Wind Power. Ecotricity pays for everything from the feasibility stage, through planning and construction to lifelong operation and maintenance. It claims that it can supply power at less than the cost of conventional electricity, with a guarantee of lower electricity prices for up to 30 years.

The Bristol Port Company commented 'Ecotricity has taken on the complex task of delivering this ambitious project, and we are delighted with the results. The three wind turbines are now delivering The Bristol Port Company with substantial environmental and financial savings.'

How can companies like Ecotricity do this? Firstly, on site power avoids having to pay for power to be delivered on the national grid from energy supply companies like E.ON and EDF. That avoids losses on long distance transmission and associated overhead costs. Secondly, renewable energy sources like wind power are rapidly becoming competitive in good sites, but still get a subsidy via the UK Renewables Obligation. Ecotricity gets Renewable Obligation Certificates for each MWh it supplies from its projects and these have a market value.

Will it spread?

It is actually quite common for large industrial estates estates to generate their own power, and also often heat, themselves, on site e.g. in medium scale combined heat and power plants, burning fossil fuel, e.g. gas. This can be cheaper than using power from the public supply. Using renewable sources like wind is just an extension of this idea, but adds an environmental bonus, and also protection from likely increases in fossil fuel costs. The fuel is free- and local. Analysis carried out by the UK Carbon Trust indicates that there is a strong case for businesses to produce their own renewable energy, with a potential for returns in excess of 20%.

And it's not just wind. Where there is a large daytime energy demand e.g for office equipment, air-conditioning, refrigeration, PV solar can be very relevant. It is fast approaching price parity with conventional sources of power in some applications and locations.

PV arrays have been installed on company warehouse roof-tops, like the German discount store LIDL, with 1.2 MW on its Logistics centre, and the 2.42MW PV FedEx Ground Woodbridge distribution hub in New Jersey in the USA. Google is also moving into PV with 1.6MW so far installed. Coca-Cola's Plant in Los Angeles, California has a 329 kW array.

PV is also being used increasingly in the automobile manufacturing and service sector e.g. General Motors has an 11.8 MW PV array at its plant at Zaragoza in Spain, Toyota's parts centre in Belgium has 1.8MW, Goodyear Dunlop has 2.4 MW at its logistics centre Philippsburg, Germany. There's also a 2.4MW Volkswagen roof at Wolfsburg, Germany.

Heating

Power production is not the only option. Heat from renewable sources is being supplied in some cases, for space and water heating e.g. solar preheating of the water needed for some industrial processes, or biomass heating for industrial processes.

The UNIDO assessment of the 2050 potential of renewables in industry says that by 2050 conventional solar heat collectors could be providing 5.6 EJ of process heat globally, while Concentrating Solar Power (CSP) using focused sunlight for high temperature heat, could add a further 2.4 EJ- making 8EJ in all, nearly 8% of total process heat needs.

However, biomass already provides over 8% industrial final energy, and UNIDO concluded that the use of biomass, primarily for process heat, has the potential to increase in the pulp and paper and the wood sectors to reach a global average share of 54% and 67% respectively of the total final energy use in each sector. It also suggests that, by 2050, biomass could constitute 22% of final energy use in the chemical and petrochemical sectors and that alternative fuels could constitute up to 30% of final energy use in the cement sector.

Globally, UNIDO suggests that up to 21% of all final energy use and feedstock in manufacturing industry in 2050 could be of renewable origin. This would constitute almost 50 exajoules a year (EJ/yr), out of a total industry sector final energy use of around 230 EJ/yr. This includes 37 EJ/yr from biomass feedstock and process energy and over 10 EJ/yr of process heat from solar thermal installations and heat pumps.

Obviously none of these renewable energy options would make sense unless attention had already be given to all the usual energy saving options- insulation, process efficiency upgrades and so on. And with solar /PV and wind you have to accept that they will not deliver power 24/7, so unless you have energy storage facilities, you still have to import power from the grid- although at times you may also be able to export excess power to pay for the imports. Biomass avoids this problem, but it has land-use and biodiversity limits.

What next?

While there are a range of renewable sources that can provide on site power directly for industrial activities, in many cases it will be more convenient and possibly more efficient to take power from large renewables projects linked up via the grid - e.g. large offshore wind farms, wave farms, tidal farms, or desert solar projects. And as the proportion of energy on the grid from these sources rises, the attraction of self-generation may decrease.

However industrial patterns may change, with new types of industry emerging, using renewables to make liquid and gaseous fuels, as well as heat and power- we are likely to see new industrial complexes using renewables to process a range of feedstocks.

This approach can be extended to a complete industrial ecosystem, e.g. recycling 'waste' outputs from industrial and agricultural processes as feedstock or energy inputs for other industries and users - cascading and integrating to increase overall materials and energy efficiency, and, where possible topping up with renewables to drive the system. As well as cutting cost ad emissions, innovation in industry can open up many new commercial opportunities in existing and new sectors.

Energy Efficiency in industry http://www.carbontrust.co.uk/emerging-technologies/current-focus-areas/ieea/pages/industrial-energy-efficiency-accelerator.aspx

Ecotricity: http://www.ecotricity.co.uk/for-your-business/on-site-wind-energy

The case for renewables in UK businesss: http://www.carbontrust.co.uk/Publications/pages/publicationdetail.aspx?id=CTA004

UNIDO report on Renewables in Industry globally: www.uncclearn.org/sites/www.uncclearn.org/files/unido05.pdf

The new UK Carbon Plan had some sensible things to say about energy and industry- it backed biomass CHP: www.decc.gov.uk/assets/decc/11/tackling-climate-change/carbon-plan/3702-the-carbon-plan-delivering-our-low-carbon-future.pdf

The battle over the UK PV solar Feed-In Tariffs (FiTs) continues, following on from the cuts of around 50% proposed by the government. That had led to major protest by PV companies and environmental groups, with a 'Cut don't Kill' campaign emerging, founded by a coalition of 20 major companies from across the solar industry. It kicked off with a Westminister demonstration calling for revision of the plans. While some reductions in the FiT were seen as fair, the scale and timing of the cuts (to be backdated to last December) were not, and would, it was claimed, cripple the industry. Alan Simpson a one time Labour MP, who has helped create the FiT system, noted that PV was 'the only sector that has delivered 25,000 new and sustainable jobs in the last 18 months'.

There were also disputes over some of the numbers used. Thus Energy Minister Greg Barker had said that the new 21p/kWh FiT for 4kW or under 'will attract the highest level of any subsidy of mainstream technologies'. But critics pointed out that micro wind turbines under 1.5 kW got 36.2p/kWh while those with under 15 kW received 28p/kWh. The trouble with this argument is that all the FiTs, these included, were under review- and they may get cut to below PV!

MP's debated the proposals just before Christmas, but, despite heavy lobbying, a motion opposing the PV FiT cuts was defeated by 292 to 220. Undeterred, Friends of the Earth, Solar Century and Home Sun then sought and obtained backing for a legal challenge from High Court Judge Mr Justice Mitting, who said ministers were 'proposing to make an unlawful decision' and as a result the court would be 'amenable to a judicial review'.

In January DECC submitted an appeal in which they noted that 'the High Court's decision was based on the view that the proposed approach to implementing new tariffs for solar PV is inconsistent with the FIT scheme's statutory purpose of encouraging small-scale low-carbon electricity generation' But DECC said 'The overriding aim of the proposed reduction in tariffs for solar PV (as set out in the recent consultation) is to ensure that over the long term as many people as possible are encouraged to install small scale low-carbon generation (including other technologies as well as solar PV) and benefit from the funding available for the FIT scheme. Without an urgent reduction in the current tariffs, which give a very generous return, the budget for the scheme would be severely depleted and there would be very little available for future solar PV generators, or for other technologies. Our view is that the urgent steps we have proposed to protect the scheme for the future are fully consistent with the scheme's statutory purpose'. It also said that 'the judicial review was premature as no decision has yet been taken, and a decision will only be taken after a full analysis of the responses to the consultation'.

Meanwhile, Energy secretary Chris Huhne acknowledged the difficulties experienced by solar firms as a result of the government's decision to cut incentives with just six week's notice, promising that the government 'will try harder next time' to minimise disruption caused by changes to the feed-in tariff scheme. But he said the ConDems had inhererited the system from the previous administration. He was reported to have complained that the fact the feed-in tariffs did not include an automatic degression mechanism for reducing the level of incentives meant the government had no choice but to impose the cuts at short notice, after "massively attractive" tariffs combined with a "dramatic crash" in panel prices had led to a surge in installations that threatened to push the scheme over budget. Critics pointed out that in fact the government could have adjusted it earlier without causing so much dislocation, and that, in fact, the PV tariff , as initially planned, did have a built-in annual price degression mechanism- set at 7% p.a for all categories. And at the time of the launch of the FiT scheme, DECC said it would increase the degression rate by a further 0.5% from 2015, although the start of the degression process was delayed by a year. The final pattern of planned reductions (for all the FiTs) is shown in a helpful table abstracted at www.peterlennard.com/fit.pdf

Be that as it may, as it turned out, a more substantial degression may have been needed, DECC had initially estimated that the FiT would put £11p.a. on consumer bills by 2020. The ConDems had upgraded this to £26 and used that to justify the cuts, no doubt also reacting to the spate of media stories about green policies being a major part of the £200 or so some said had been put on bills, and the talk of £2k or £3k bills by 2020.

However, that's all now been put in proper perspective with the governments advisory Committee on Climate Change reaffirming that it was gas prices that had led to most of the energy price rise- 64% of price rises were caused by increasing wholesale energy prices and only 6.5% by support for low-carbon energy. Households that have dual-fuel (gas and electricity) bills had seen their energy costs rise from £605 in 2004 to £1060 in 2010, an increase of 75%. But only £30 - or 6.5% - of this increase related to support for low-carbon energy, compared to £290 for increasing costs of gas and supplier costs. It said that green policies overall would only add around £110 to annual bills per household in 2020, and it could be just £25 if the energy savings programme was successful.

Independent green energy retailer Good Energy, have argued that the direct cuts in tariff levels for PV may not actually be the biggest issue in term of slowing PV growth - the proposal to limit FiTs to buildings reaching a high set level of energy efficiency (above 'C') could have even more impacts. Good Energy said that only about 10% of UK homes would be eligible and that the Green Deal upgrade loans won't actually change that- at best getting to an 'E' rating. So most homes will remain ineligible.

Overall it does look as if, one way or another, the PV programme has been boxed up. We now await the proposals for the FiTs for the other renewables. Further cuts are expected.

It's Christmas, so here's a light-hearted contribution looking back over the year.....although maybe not quite so light-hearted, given the troubled year we've just been through, what with the quake and tsunami in Japan - and Fukushima.

The UK did send Japan an early Christmas present, but they may not have wanted it: a shipment of high-level radioactive waste.  This derived from spent fuel from Japanese nuclear plants, which had been reprocessed at Sellafield's Thorp facility to extract plutonium and uranium, some of this maybe later ending up in mixed oxide 'MOX' fuel, for use in Japan- which now they probably don't want either!

Another perhaps less serious problem they had was when the seawater intakes of a nuclear power plant in Japan got clogged with jellyfish. The same thing happened in Scotland at Torness. Maybe they were trying to tell us something?  So maybe was the  three-eyed fish  that a group of fishermen  reportedly caught  in a lake near a nuclear power plant in Argentina.

Nature does seem to remind us who is boss occasionally, with the tsunami in Japan being the most obvious recent example. That has it seems also happened in the past in the UK. What seems to have been tsunami evidently hit the English and Welsh coast of the Severn estuary in 1607, with the flood recorded with a metal peg set into the wall of a church (built on a low rise) at adult chest height, and showing surrounding ground had a flood height of 4 metres. It caused 2000 deaths of people of the villages and much loss of livestock.  I do hope the designers of the new nuclear plants proposed for sea-level sites on the estuary at Hinkley and Olbury remember that.

However let's move on from nuclear. Renewables had their share of crazyness and problems this year too, with, for example, the 1/6th scale prototype of Norway's Sway floating wind turbine sinking in heavy seas in November.  And a 2MW wind turbine caught light in fierce gales in Scotland in December The global recession also took its toll with US company Clipper Wind abandoning development work on the 10MW Britannia offshore wind turbine concept.  But, technical and economic hiccups like this apart, the main problem facing renewables seems to have been heavy handed government intervention. Thus PV solar got hit twice with a 72% and then 50% cut in UK Feed In Tariffs. The argument was that PV solar had boomed too fast. Rapid growth  was an issue that also seemed to hit on land wind power- there were problems with excess wind generation in Scotland, leading to curtailment of valuable output and provocative compensation to the generators. The main reasons seem to be that the grid system is not ready for it.  But at least we have now agreed on a new design for grid pylons -a 'T'- shaped tower won the national competition. 

What we haven't quite agreed on it s what to do with the electricity- use it as normal, or also for charging up electric cars, and running heat pumps. That would help balance out night-time excess power.  But we could also store it as hydrogen.  I was much taken by a quote I came across from a talk given in Cambridge in 1923 by J.B.S Haldane, who predicted: "The country will be covered with rows of metallic windmills working electric motors which in their turn supply current at a very high voltage to great electric mains. At suitable distances, there will be great power stations where during windy weather the surplus power will be used for the electrolytic decomposition of water into oxygen and hydrogen".
http://en.wikipedia.org/wiki/Daedalus;_or,_Science_and_the_Future

Ah, no, some say we may not need exotic new supplies like this  - since we will have lots of shale gas.   A bit surprisingly perhaps, Chris Huhne undercut some of the hype about that, pointing out that  it had  'as not yet lit a single room nor cooked a single roast dinner in the UK'.  The collapse of the Longannet Carbon Capture and Storage project also put CCS into a somewhat longer time frame, and that's worrying if we are to rely of gas in to the future.

Which, for now, leaves us with nuclear and renewables slogging it out for a place in the sun, or rather for their share of the 'Contracts for a Difference' when ever they finally get going. It's not quite clear to me how that is going to work.  With no direct Obligation on anyone to take specific types of power, just overall government indicative supply targets, I assume it will be up to the market- which will presumably veer towards whichever option can offer the best deal in the short term. That is far from clear. On land wind looks likely to be the cheapest of the main non-fossil option at present, depending on how you do the sums and what other subsidies are on offer. But you get the feeling that the government sees nuclear as special:  it gave an early Christmas present to Sheffield Forgemasters in the form of a loan of up to £36 million "to continue its drive into civil nuclear and steelworks plant production."  But that's not a subsidy honest!  And even if it was then, they would no doubt say, similar offers have been, or will be, made to renewable projects. But a new £3bn MOX plant at Sellafield?  Difficult to justify...especially when the last (£1bn +) one didn't work.

Personally, rather than leave it up to the market, or backstage funding deals by civil servants, I'd rather leave it up to the democratic process to decide on big issues like which major technology to invest in.  But that's not our way any more, at least not until things go seriously wrong.  Then you may get terrible results, like 94% of the public voting against nuclear, as happened earlier this year in Italy. It couldn't happen here!

Genetically engineered food had not exactly been popular in the UK, with many people being worried about the risks. Quite apart from the dangers of cross-species gene transfer, some are concerned that the underlying aim is to enable suppliers to lock farmers into dependence on them. More generally, some see it as part of a wider claim that 'technology can fix everything, don't worry about impacts'.

Views like this are likely to shape reactions to the latest idea- genetically engineered energy crops. The back-story is that the first generation of biofuel crops has been widely criticised for being low yield, land hungry and undermining of food production. The second generation of non-food crops, it is claimed, will be better. But genetically, modified crops could, it's said, be even better- with much higher yields, and more resistance to drought, pests and diseases.

In fact in a new report on 'Next generation biofuels and synthetic biology', the Foundation for International Environmental Law and Development (FIELD) says that the aim is to go beyond simple genetic modification 'by splicing a few genes from one organism into another' and on to designing 'entirely new life forms with pre-selected functions, like the microbes which will digest trees and grasses and ferment them into biofuels, or the algae which will harvest solar energy to produce oil'.

Well actually that sounds interesting. So why not? FIELD offers some compelling arguments.

Minor genetic adjustments may not sound too horrific- it's what nature does slowly and we do a bit faster via selective breeding. But FIELD quote the Royal Society explanation that 'the synthetic biologist seeks to build a bespoke system (such as an organism) by re-designing an existing system or constructing one from scratch using parts taken from nature or specially designed. This approach can lead to organisms...with properties not found in nature.'

FIELD report that some synthetic biologists are designing 'a biological shell which will express synthetic DNA as flexibly as a computer runs programmes. The shell is created by disabling the genes of an existing organism one at a time and removing those that can be removed without killing the organism'. Others seek to catalogue and assemble biological parts like Lego bricks. FIELD says 'BioBricks, a leading effort of this type, is a registry of DNA sequences that each reliably perform a specific function. Each "brick" is designed to be compatible with the others.' Still others aim to construct synthetic life forms entirely from scratch using DNA synthesisers, 'the biological equivalent of word processors'.

FIELD notes that the world's first self-replicating synthetic genome, announced by the J. Craig Venter Institute in May 2010, was constructed in this way. Venter described it as 'the first self-replicating species we've had on the planet whose parent is a computer.' That certainly sounds worrying.

FIELD says 'It is extremely difficult to anticipate the risks and harms of a new science like synthetic biology, and therefore of next generation [GM] biofuels. Traditionally, the risks of new genetically engineered organisms are assessed by comparison with their known relatives. Containment rules and risk mitigation strategies are then set based on the rules for the known relative. But synthetic biologists are capable of designing organisms with no relatives in nature'.

It accepts that 'building "terminator genes" into synthetic organisms, or making them dependent on artificial substances, may decrease the likelihood of uncontrolled proliferation', but asserts that 'uncontrolled proliferation may occur despite best efforts at containment. Synthetic micro-organisms released into the environment, accidentally or intentionally, could share genes with other micro-organisms through horizontal gene transfer or evolve beyond their functionality. One hypothetical, worst-case scenario is a newly engineered type of high-yielding blue-green algae cultivated for biofuel production unintentionally leaking from outdoor ponds and out-competing native algal growth. A durable synthetic biology-derived organism might then spread to natural waterways, where it may thrive, displace other species, and rob the ecosystem of vital nutrients, with negative consequences for the environment.'

It goes on 'Synthetic biology also presents new bio-security threats. DNA sequences and design software are available online and synthesised DNA is available by mail order. In 2002, a team of researches at the State University of New York demonstrated the potential threat by recreating the polio virus from sequences of DNA ordered by mail.'

It then outlines the current state of play on regulation, but warns that 'there is little clarity on how synthetic biology is currently regulated under domestic and international law, and no clarity on how regulation should proceed'.

There are vast amounts of money potentially to be made from synthetic biology, and, given the rapidly developing field, those seeking to devise regulatory controls also face, in effect, a moving target. So perhaps it's hardly surprising that regulation is problematic.

Worried? FIELD clearly is. So too are Friends of the Earth and Greenpeace. Some may see all this as just scare-mongering by those who are basically anti-scientific progress, but there would seem to a valid cause for some concern. One way or another, we seem likely to be in for another round of the GM debate.

FIELD report: : www.field.org.uk/files/syntheticbiologybiofuelsbriefingpaper.pdf

The UK governments new Carbon Plan, produced as required under the Climate Change act, looks at a core strategy based on a mix of renewables (45GW), Carbon Capture and Storage (28GW) and nuclear (33GW) by 2050, but also includes three alternative possible scenarios. In one, if CCS does not take off (just reaching 2GW) and renewables are restricted to 22GW, up to 75GW of nuclear is built by 2050. In the second, with CCS moving up to 40GW, nuclear is then at 20GW and renewables 36GW. However, in the third, renewables move up to 106GW, with nuclear at 16GW and CCS at 13GW by 2050. All three future scenarios are at http://2050-calculator-tool.decc.gov.uk

Some might say having three main options spreads the risks. Certainly there are risks and problems with each and it could be argued that some of these are sufficiently serious that the options should be reconsidered.

Nuclear Balance

We are used to hearing about the short-term economic, safety and security risks of nuclear, but there are also longer term issues- and beyond the usual one of waste disposal. In a report on 'Energy balance of Nuclear Power Generation' the Austrian Institute of Ecology and the Austrian Energy Agency have had another look at the issue of the full lifecycle energy requirements for providing the fuel for nuclear power plants. They looked at all the previous studies and concluded that, assuming the low growth scenario of the World Nuclear Association (WNA) and the IAEA data on uranium resources from currently operated uranium mines, reserves will be sufficient until 2055. If mines which are currently being developed are also taken into account, the uranium reserves would last until around 2075 in the low WNA growth scenario. However emissions from the increased use of lower grade uranium ore will rise, since uranium fuel production will get much more energy intensive.

With ore grades between 0.1-2%, the energy expenditure for generating one kWh of final energy is put at between 2-4%. With ore grade of 0.01% and 0.02% the energy expenditure rises to 14-54% and the resulting CO2 emission amount to 82-210 g/kWh. By contrast, CO2 emissions for renewabales are put at 3 - 60 g/ kWh.
The study notes that one third of currently operated uranium mines have an ore grade below 0.03%, but if we push ahead with more nuclear, then we reach the point when continuing become increasingly pointless in energy/carbon terms.

You might of course still continue with nuclear despite that, but below about 0.008 to 0.012 % ore grade, the report notes, 'the energy expenditure for the uranium mining is so high, that the overall energy balance turns negative... From this ore grade on, the operation of nuclear power plants does not generate any energy surplus.'

The only option then, if for some reason you wanted to continue to use nuclear, would be to use renewables to provide the energy for uranium mining and processing. It's just conceivable that uranium mines in Namibian might use solar PV power and those in Kazakhstan wind power, and that uranium ore processing plants will also use renewable sources, but surely it would not make sense to use renewable so wastefully. /www.ecology.at/lca_nuklearindustrie.htm

CCS delayed or dead?

The demise of the proposed coal-fired Carbon Capture and Storage pilot project at Longannet in Scotland, due to the high investment cost, led some to say CCS was dead as an option in the UK. One key issue for CCS evidently is the need to cover the risk of accidental sudden large scale CO2 release at some future point. Hard to quantify! For a spirited demolition of CCS see Eurosolar president Prof Peter Droege's review: www.europeanenergyreview.eu/site/pagina.php?id=3251

He notes that the IEA roadmap envisions that by 2050 3,000 CCS projects will capture and store 10 billion tonnes of CO2 annually, about a third of current global carbon emissions. He says that's 'a tall order, in view of the fact that not a single utility-scale CCS plant is currently operating on the planet'. He reports that 'American Electric Power, cancelled plans to deploy CCS at one of its big facilities - even though the U.S. government offered to pick up half the tab.' At best he says 'most observers peg 2020 or 2025 as the earliest date by which enough large-scale CCS plants are on-line and returning evidence to prove technical viability' However 'renewables are set to achieve grid-parity over the same period. This means that there will be risk that CCS becomes economically obsolete just as the returns come in.'

He concludes 'Funds can be far better spent on stimulating demand reduction and energy efficiency, improving renewable energy storage and two-way energy grids to balance intermittent generation, and - last, not least - to bank on 'carbon storage' that works: namely the active bio-sequestration of greenhouse gases in wetlands, moors, humus rich agricultural soil and in growing new forests.'

Nevertheless, CCS enthusiasts argue that it could be competitive with renewables and avoid their grid balancing issues. Some small pilot projects exists around the world and the UK government is still keen to press ahead with its £1bn CCS competition, if it can find a new candidate. In addition, there are it seems still 6 industrial consortia keen to compete for maybe 4 UK 'slots' in the EU subsidised (NER-300) CCS demo programme. The UK's proposed new CfD support system should also offer support for CCS, cheaper gas-fired plants included.

The Longannet coal project was to involve post-combustion capture and access to offshore storage via a 170 mile long pipeline. Some say a better first option would gas fired pre-combustion capture schemes, possible even using bio-methane in existing CCGTs. Many environmentalists are unhappy with CCS, not least since they say it will deflect support from renewables. But biomass-fed CCS would be carbon negative, assuming the biomass is fully replaced, so some see fossil-fed CCS as just a preliminary stage and as a bridge to a much more sustainable approach.

For an overview of EU CCS prospects: www.europeanenergyreview.eu/site/pagina.php?id_mailing=2 23&toegang=115f89503138416a242f40fb7d7f338e&id=3361

Renewables

Renewables certainly have their problems, not least, for some of them, intermittency, although that can be overstated. It's a relatively minor operational issue when the renewable input is below around 20%, and can be dealt with without leading to significant extra emissions using standard approaches, including the new breed of flexible, but high efficiency, combined cycle gas turbines, like the FlexEfficiency 50, developed by GE: www.ge-flexibility.com

As more renewables come on line, we may need more energy storage capacity, and there are some clever new ideas emerging in the hydrogen field. The electrolysis of water is sometimes seen as inefficient, especially with variable electricity inputs, but RE Hydrogen say that their novel materials electrolyser can handle intermittent electricity inputs, usually a bugbear for wind or PV powered hydrogen generation: www.rehydrogen.com/id1.html

More radically, there's a new idea for thermal dissociation of water at high efficiency using high temperatures and solid acid materials: www.sciencedirect.com/science/article/pii/S0360319911010007

Meanwhile, Airproducts has developed a cryogenic system for storing energy as liquid air. It claims that overall energy conversion efficiencies of 75-85% are possible with up to 100MW storage for 12 hours: www.airproducts.com/industries/Energy/Power/Power-Technologies/product-list.aspx?itemId=%7B7D677622-F274-40B1-8EC9-F6D33CC19C5E%7D

Innovations like this, and also upgrades to the basic renewable generation technologies, are moving ahead rapidly around the world, with costs falling rapidly. And if you want to spread risks, well there are dozens of different types of renewables- real diversity. I know where I'd put my money!

Local community initiated and run renewable energy projects seem to be catching on around the EU. Wind co-ops have been very common in Denmark for many years- about 80% of the wind generation capacity is locally owned. It seems to be one reason why local opposition to wind is much lower than in the UK, where there are very few locally owned projects. As the Danes say ' your own pigs don't smell'.

It's similar in Germany where many projects are locally owned. A comparative study conducted in Germany by researchers from the University of Amsterdam concluded that the social acceptance of wind power is very high in general, and even higher when community members are directly involved. 62% of the residents near a community owned wind farm expressed a positive or very positive opinion on the wind farm in their neighbourhood and only 1 % had a negative or very negative attitude. In the case of the non-community owned wind farm, 47 % expressed a neutral opinion, while 26% were positive or very positive and 27 % were negative or very negative.

Stefan Gsänger, World Wind Energy Association Secretary General said: 'If we want to reach a 100 % renewable energy supply worldwide with wind energy as a cornerstone, we have to make sure that the local communities actively support this endeavour and that they benefit from the wind farms in their vicinity. Community Power ownership models offer an excellent approach to achieving this objective.'

The local ownership idea has also spread to other technologies. A well as being a leader in wind, Denmark, makes a lot of use of district heating, and it is now developing some solar-fed heat networks, with some of them being run as community cooperatives.

For example, the Brædstrup District Heating co-op owns the network and heat meters and delivers district heating to almost 1,400 households, covering around 95 % of the heat demand in the town. Supply temperatures are between 72°C in summer and 80°C in winter, and all heat meters are remotely read at years end. A General assembly is held once a year, mostly in March, and all members of the cooperative have access.

The 2006 general assembly decided to invest in a major solar heat collector panel installation to go along side the existing gas-fired plant. Financial support was received from the national TSO (€480k), and installation took place in 2007. Solar heat production from the 5.6MW 8.000 sq.m solar array was 3,229 GWh in 2009.

Their next project is to expand the solar array to more than twice the size of the existing one, and to develop a heat storage based on 100 holes in the ground, each with a pipe loop, where surplus solar heat can be stored and extracted later with the help of heat pumps. Financial support has also been applied for and received for this experimental project to the sum of €850.000. If it goes well, further expansion is foreseen.

Many more community solar heating projects like this have emerged, with back up heat stores, including the 13MW array at Marstal, soon to be doubled: see www.solarmarstal.dk. For more see: www.solar-district-heating.eu

Biomass is also being used as a basis for local community projects around the EU. For example, Juehnde is the first bioenergy village in Germany, meaning that it produces its electricity and energy for heating and cooling locally from renewable biomass resources. While the project was started in 2000, it reached the self-sufficiency level for energy in June 2006. In 2007, Juehnde produced around 5 m kWh electricity, while the village's consumption, with 750 residents in 200 households, 75% of whom are connected up, is about 2 m kWh. The excess is sold to energy providers. The major feedstocks for electricity generation are methane (biogas) produced from fermented liquid manure and locally grown energy crops. Heat is produced as by-product from electricity generation in a 700kWe biogas fired CHP plant and in Winter from burning woodchips. The major motivation behind the use of biomass is climate and resource protection. It's run as a co-operative.

Local agriculture, with 9 local farmers, is the backbone for operating the project, as 25% of the 1300ha farmland and 10% of the annual forest wood growth from its 800ha of woodland is contracted for bioenergy production. But there are also two PV solar arrays- 10 and 8.6kWpeak

The project received €3m in financial support from Federal, regional, and local government agencies. It proved so successful, that a number of other bioenergy villages are being developed, even without the same government support.

The largest so far are Rai-Breittenbach with 900 residents 90% of whom are served by 3.5MW of biomass and 30 kW of PV; Iden with 1000 residents and 250kW of biogas and 850kW of wood fired generation, serving 75% of the population; and Randeqq, with 1300 people supplied by 2.7MW of wood generation and some solar thermal, supplying 50% of the population. And more are on the way.

More at www.bioenergiedorf.de

So how far have we got in the UK? The Bay Wind co-op in Cumbria was the first breakthrough, and several more wind co-ops have followed including Westmmill near Swindon, also now a site of a solar co-op: www.westmill.coop/westmill_home.asp

Scotland has been leader in the field, with support from the Community and Renewable Energy Scheme. That has assisted 105 electricity generating projects over the last 2 years, which it's claimed should result in an installed capacity of 53 MW and more are on the way. Overall, Community Energy Scotland have estimate that there is about 180 MW installed capacity of community owned renewables schemes currently under different stages of development and many more are planned. The 2020 Routemap for Renewable Energy in Scotland included a commitment to expanding the contribution from community schemes, with a new target of 500 MW community and locally- owned renewable energy by 2020.

One of the most recent projects is the community wind power scheme at Udny, Aberdeenshire, which is to be followed by Torrance Farm Community Wind Energy project at Harthill. A Community Trust Company has been formed to disburse the profits from the 800kW Udny scheme - £4 m over 20 years - which could go to fund projects such as a new community hall, a youth hut, a cinema or the expansion of a local paths network.

AAT has been trying to do the same thing in Wales, www.awelamantawe.org.uk/ and there are many new projects emerging across England, via groups like CoRE, the Community Renewables Co-op: www.corecoop.net; FREE, Fowey Renewable Energy Enterprise http://freefowey.co.uk ; and WREN, Wadebridge Renewable Energy Network www.wren.uk.com.

However it's up uphill struggle, not least to raise finance. The Renewable Obligation is not much use for smaller schemes- it's designed for large-scale commercial projects. On the continent the various Feed In Tariffs were by contrast much more use, and there were hopes that the UKs small FiT could help, but its support for PV has now been drastically cut back. The new energyshare.com scheme, backed by British Gas, is promising, with hundreds of hopefuls signing up, but it seems we have some way to go before we can expect to see anything like what's happening elsewhere in the EU.

Deserts get a lot of sunlight and there is currently something of a race to develop and deploy the best technology to exploit this free energy.

Concentrating Solar Power (CSP) systems with mirrors, dishes or parabolic troughs focussing the sunlight to raise steam to run a turbines are currently in the lead. There have been some major developments in Spain and the USA, but also now in N Africa and the Middle East, with new projects opening in Morocco (the 470 MW Ain Beni Mathar hybrid project) and Egypt (the 150 MW Kuraymat hybrid project). And more are planned. For example, the UAE is planning a 100MW project, and the Egyptian National Plan for 2012 -17 includes a 100MW CSP plant in South Egypt, while the follow-up National Plan for 2018-2022 has 2,550 MW of CSP. The German-led Desertec project seeks to build on the CSP option, making supergrid links back to the EU. It has plans for a €600m 150MW CSP plant in Morocco as a first stage. www.desertec.org/

It's hard to know what the impact of the recent political convulsions in North Africa may be, but CSP does seem likely to continue to move ahead in the region, as well as elsewhere- the largest CSP array so far planned is the 1 GW Blythe project, being developed in California by Solar Millennium LLC, on which more later.

A solar industry roadmap, as outlined in a study by A.T. Kearney and the European Solar Thermal Electricity Association, ESTELA, sees solar thermal reaching 12 GW of installed capacity globally by 2015, 30 GW by 2020 and between 60 and 100 GW by 2025. But that may prove to be pessimistic- CSP is not just limited to desert areas. For example, South Africa has a plan for a 5GW solar park, with the initial 1000MW phase, aimed for 2012, incorporating an already planned Eskom 100 MW CSP plant, which has received part funding from the World Bank. The Indian Ministry of New & Renewable Energy's National Solar Mission aims to generate 20GW of grid linked solar power by 2022, 50% CSP. And in Australia a new 'Zero Carbon Australia 2020' report has 42.5 GW of CSP supplying 60% of total electricity there by 2020! http://beyondzeroemissions.org/zero-carbon-australia-2020

However a rival technology - Concentrating Photo Voltaic (CPV) power - may challenge CSP. CPV uses conventional solar cells but with large arrays and sunlight focussing arrangements, as with CSP. The crucial point is that mirrors are cheaper than solar cells. There are already some very large projects in existence, 20 MW or more globally, including the 4MW array in Springerville Arizona, and the 10MW Masdar project in the UAE. And costs are falling- some say faster than for CSP.

A GTM Research study claims that the growing market for CSP is being seriously challenged by the rapidly falling price of solar photovoltaics. GTM predicted that, although the CSP market will grow by around US$7 billion over the next two years, it will then tail off, due to the dramatic decrease in the cost of solar PV panels. So although CSP project costs are set to decline between 3% and 7% per year from 2010 to 2020, PV costs will also continue their own substantial declines, with PV expected to maintain a cost advantage (on both a cost-per-watt and cost-per-kWh basis).

In fact, some utility companies are already choosing PV over CSP for future solar plants. For example, Masdar, the Abu Dhabi government backed renewables company, had been backing CSP. Its $600m, 100 MW Shams 1 CSP unit should be completed in 2012. But the newly proposed 100MW Noor solar PV plant will cost less than Shams 1, because of improving efficiency and "the normal learning curve for the industry," according to Frank Wouters, director of Masdar Power.

The cost battle is also evidently having an impact in the USA. According to an report carried by Renewable Energy World, conventional residential rooftop solar PV system in Los Angeles can deliver lower electricity at less cost per kilowatt-hour than the most cost effective, utility- scale concentrating solar power plant. It noted that CSP had higher operations costs and a higher cost of capital than for the residential rooftop system, and there were also transmission infrastructure and efficiency losses, which would increase the cost of power from the CSP plant further.

It may be too early to make longer-term policies on the basis of calculations like this, but PV and CSP do seem to be rivals. CSP has the major advantage of being able to store heat in molten salt heat stores, so that power production can be continued after the sun goes down, while most PV cell performance falls with time and rising temperature. But then CSP plants have to have some form of cooling as with any steam raising system- air cooling is less efficient than water cooling, but one thing deserts don't have is water, so it would have to be piped in, adding to the cost. And with cell cost falling, PV may increasingly have the edge. After all, its not just domestic roof top PV systems or simply arrays that are in contention, new ideas for very large-scale CPV systems, including energy storage, are also emerging

Earthscans 'Energy from the Desert' three-volume book set edited By Kosuke Kurokawa et al , details the background and concept of Very Large Scale Photovoltaics (VLS-PC). Overall the authors are very optimistic- they say VLS-PV can be competitive with fossil fuel-fired plants assuming economic energy storage is available- they look to Vanadium flow batteries. And longer term they see large scale PV solar are becoming a dominant energy option.

CSP and CPV both have similar environmental impacts in terms of their land use footprint, with some projects in the USA falling foul of local concerns about desert wildlife, and CSP's need for water. http://solar.ehclients.com/images/uploads/envimpactsoflg-scalesolar_projects.pdf

But there should be plenty of desert areas around the world where there are minimal land use conflicts, and some North African CSP projects have been seen as being used partly for desalination- with sea water piped in over perhaps long distances from the Mediterranean, possibly linked to Solar greenhouses projects. www.seawatergreenhouse.com. www.saharaforestproject.com

New ideas may also emerge. It's conceivable that CSP and CPV or PV arrays could be combined. There are some small-scale hybrid solar thermal-PV systems for domestic uses, the big advantage being that the solar heat absorbers keep the PV cells cooler, so they operate more efficiently, in tandem, with heat collectors in wafers in a sandwich with PV cells. Although it's harder to see how this could be achieved with large scale focussing systems, it could be worth exploring in hot desert environments.

Hybrid CSP/PV systems were mentioned as a future option by the developer of the 1GW Blythe solar project in California mentioned earlier. Reflecting the changing fortunes of CSP and PV, it has now decided that the first 500-MW phase will be switched from CSP to PV technology because they say market conditions in the US now favour PV. But they also noted that CSP was a valuable 'grid-stabilizing renewable energy source with storage capabilities,' so a combination might prove to be the best option. www.powermag.com/POWERnews/3985.html?hqe=el&hqm=2269044&hql=45&hqv=0c00b9b673

For more: Peter van der Vleuten, Free Energy International: www.energyfromthedesert.com/index.php?option=com_content&task=view&id=13&Itemid=31