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March 2013 Archives

The UK government has been trying to have its cake and eat it. It wanted nuclear but didn't want to have provocative and visible subsidies for it. So it came up with a Contracts for Difference (CfD) system, which will replace the Renewables Obligation (RO) from 2017 (or for some projects, earlier) and would apply to nuclear, renewables and CCS projects. However it will allow different levels of support to be offered to each. As Energy Secretary Ed Davey put it, 'there are likely to be variations in CFD designs between one technology and another, and perhaps also between different projects within the same technology''

Nuclear, renewables and CCS projects are all eligible to apply for CfD contracts with 'strike prices' being negotiated separately. However there would be an overall cap on how much extra cost could be passed on to consumers, via the Levy Control Framework (LCF) cap, currently set at £2.35 bn for low carbon electricity, rising to £7.6bn in 2020/21.

Some feared that, if EDF got a good CfD contract for the proposed 3.2GW Hinkley EPR plant, that would soak up all the money available under the LCF. However, given the long delays, the government is now looking to 2030 for the start up for the new nuclear plants. So the CfD cost will not fall under the existing LCF, but under whatever LCF cap emerges later. Which means that, up to 2020 or so, there is room for new renewables.

Even so, in terms of setting a price for nuclear, DECC was caught in a bind. On land wind currently gets around £90/MWh under the RO system, and offshore wind around 120-130/MWh, with that expected to fall to £100/MWh by 2020 as the technology develops. However it has been claimed that nuclear would need maybe £120/MWh and perhaps as much as £160MWh to be economically viable. ('Cost estimates for nuclear power in the UK', Imperial College London, ICEPT Working Paper 2012/014, 2012).

A high EDF nuclear CfD strike price would set a precedent for similar deals for renewables, and break the LCF limit. That's one reason why DECC wanted to keep the EDF strike price low. But it also wanted the EPR. So we may end up with a compromise, a moderate strike price for nuclear, below £100/MWh possibly, but with a long contract period, perhaps 35 years. We are still waiting for the announcement. It seems to still be touch and go, with ancillary infrastructure support 'sweetener' deals maybe being offered. However, the Energy and Climate Change Select Committee warned that 'new nuclear should not be delivered if the price is too high', and suggested establishing a 'Plan B' in case it all went wrong, especially since a failure to get agreement on this would probably undermine the next projects in line for nuclear support, such as Hitachi's proposed ABWR's at Wylfa and Olbury.

Meanwhile, renewable energy developers are angling for similar arrangements with longer contracts, not just the 10 or 15 year ones currently on offer. Indeed for the newer less developed options, like marine renewables, even more is being asked for. For example, RenewableUK had already called for the initial CfD strike price for the first generation of tidal arrays to be set at £280 to £300/MWh and for wave technology, £300 to £320/MWh.

DECC has announced a 'Final Investment Decision Enabling programme' for renewables projects to get started and strike prices agreed before 2017, possibly even starting up in 2014/15, as soon as the CfD system is in place. It's available to projects over 50MW onshore and 100MW offshore.

DECC had been trying to establish around £100/MWh as the bench mark CfD price for new projects due to start up in 2020, but had agreed that some, like marine renewables, would need extra, justified on the basis that these were strategically important technologies for the UK. This largess did not seem to extend to PV solar; it has been getting around £160/MWh, having been cut back. The battle continues, with CCS yet to join the fray.

However the government seems to want to raise the stakes. Its new Nuclear Industry Strategy explores and indeed sounds very positive about a possible major expansion to 75GWof nuclear by 2050. It says 'Nuclear could contribute roughly 40-50% to the energy mix under this scenario, compared with nearly 20% today'. (Actually it's 17.8%) And it presents a series of Industry-derived pathways forward and progress milestones, which it says it 'fully supports'. `It 'will work with industry to see this vision delivered'. 75GW! The biggest programme in the EU. Indeed, in percentage terms, in the world.

What emerges from the flurry of new reports and commitments is an almost complete capture of government policy by the nuclear industry, based on a conviction that nuclear will lead to significant economic benefits to the UK. As one time DBERR energy Minister, and now Nuclear Industry Association Chair, Lord Hutton, puts it in the new Nuclear Industry Strategy, 'the UK is once more at the forefront of a global revival of interest in nuclear activities, and well positioned to reap the very considerable dividends that will result from a resurgent nuclear sector'.

Fortunately that has not so far led to blank cheque funding, leaving aside the £90bn or so clean-up legacy, but neither has it been mean. The government says it provided £66m funding for nuclear R&D in 2010-11, including for fusion, and it supported the 2009 establishment of the Nuclear-Advanced Manufacturing Research Centre, with additional investment of £37m in 2012. The TSB Nuclear Feasibility and Near to Market Nuclear Innovation Support programme got £18m, and around £22m has gone on the National Skills Academy for Nuclear, plus £10 m support for nuclear PhDs.

Next up, a whole new raft of support including £15 m for a new National Nuclear Users Facility, with bases at Sellafield (NNL), Culham, and Manchester University's Dalton Lab; £18m from TSB for 35 nuclear R&D projects; and £12.5 m to join the Jules Horowitz Test Reactor programme which is being set up in France. And possibly more to come.

However the government admits that there may be problems. Its new 'Long Term Nuclear Energy Strategy' says the main current priorities are to get the cost of the proposed new plants down and find somewhere for the wastes. The latter seems likely to be hard, given the decision by Cumbria County Council not to volunteer. And on the economics, the government says 'the size of the nuclear programme will depend on the effectiveness of developers initially being able to build to time and budget, and subsequently being able progressively to reduce costs through experience and economies of scale.' It went on 'the Government challenges the nuclear industry to reduce the levelised costs of new nuclear generation and will work with the Nuclear Industry council and the R&D community to do this'. With costs and delays escalating, for example for the EPR'S being built in France and Finland, this seems a long shot.

It has been claimed that if Scotland goes independent of the UK it will find it hard to sustain its ambitious renewable energy programme, which aims to match 100% of Scottish electricity use from renewables by 2020. It already gets over 36%, but that expansion has partly been due to the support of the UK wide Renewables Obligation, which passes on the cost to all UK electricity consumers. The income from just Scottish consumers (10% of the UK) would clearly be much less. A report by Dave Toke and others 'Delivering Renewable Energy Under Devolution', published in Political Quarterly, says that 'funding a significant expansion of Scottish-based off-shore renewables under independence would lead to considerable increases in Scottish electricity prices, something that a Scottish government would find hard to sustain politically'.

However it is not clear whether, after independence, it would come to that. The new (lesser!) UK would need the Scottish projects to meet its renewable energy targets, if they were still to be retained, so the new UK would have to continue to support Scottish projects, new and old. The Scottish government said that it 'believes the current, integrated GB electricity market should continue post-independence, as it's in our mutual interests. Given Scotland's vast renewable resources, with independence, it will be in the rest of the UK's overwhelming interests to ensure support arrangements are in place to secure Scottish renewable energy.'

At present, Scotland supplies around half of the UK's renewable electricity. But the next phase of expansion in Scotland might cost more, since, given the geomorphic differences, offshore wind sites there are less easy to develop. Would UK consumers be happy to fund that?

Scotland's targets - not enough?

It would be tragic if the inspiring Scottish plans came unstuck, but then again, while some think they are unrealistic or too radical, some think they are actually too limited. The Scottish governments new Report on Climate Proposals and Policies got a bit of flack for not being sufficiently bold across the board. The Scottish Greens, said: 'This is clearly a government in denial about the problem. It needs to start putting its money where its mouth is. Ministers continue to pin hopes on unpopular ideas like electric vehicles and unproven technology like carbon capture.' Scotland has got emissions down by 24.3 % since 1990, but partly it seems by carbon trading, and some say it is falling behind and won't reach its admittedly ambitious 42% cut by 2020 target.

Part of the problem is that the SNP have focused mainly on renewable electricity, with high profile targets. As noted above, Scotland already gets over 36% of its annual electricity needs matched by renewables, mainly wind so far, plus existing hydro. With more projects coming on line, it is now aiming to get 50% of its electricity from renewables by 2015. And its 100% by 2020 target is way ahead of any other country, Denmark apart, certainly including the UK as a whole, and all with no new nuclear.

However Scotland is still exporting power from fossil and nuclear plants, and the picture in terms of heat and transport demand is not so impressive. Overall it plans to obtain 30% of its total energy from renewables by 2020, with renewables supplying 11% of heat by then, mainly from biomass-fired CHP. Its forecasts for demand reduction are quite challenging, but not dramatic - 12% by 2020. Even so, by 2030 it aims to be 'largely decarbonised', and to have phased out nuclear generation. To complete the decarbonisation process in the years following 2030, it will presumably seek to expand renewable heat supply, as well as developing strategies for transport fuel. But to judge by the new Climate policy report, it's only just starting out on all that. Apart from some welcome support for CHP/district heating, it looks very similar to DECCs efforts, such as they are.

Using its devolved powers, Scotland has been able to develop a challenging energy plan for electricity. Some say that if it gained full political independence, it might be able to do even better, but for a viable sustainable energy system, continued and indeed upgraded links with the UK, and also with other EU countries, are essential e.g. via the proposed north sea supergrid. It will be interesting to see how this all plays out in the debate over independence.

Denmark provides an example

It is not impossible to combine independence in a small country with intergration: like Scotland, Denmark is aiming to get 100% of its electricity matched from renewables by 2020, mostly wind, with gross energy consumption reduced by 7.6% in 2020 compared with 2010. Renewables would then be providing 35% of total energy, with, as now, some export and import of electricity to balance the system:

And then they plan to move on to be totally carbon free by 2050, with the use of all fossil fuels being phased out, including for transport, and renewables taking over :

The Danish Heat Plan is worth a look. There will be a ban on installing oil- and gas-fired installations in new buildings from 2013. And from 2016, there will be a ban on installing oil-fired installations in existing buildings in areas with district heating or natural gas as alternatives. District heating networks currently supply about 60% of Denmark's domestic and commercial heat, and it has been suggested that by 2050 around 40% of the district heating load, at present partly met by biomass fuel, could be met by solar combined with interseasonal heat stores.

Solar and biomass aren't the only options. Denmark already has some heating provided by wind energy- with immersion heaters in a large heat store linked to a district heating network, using excess wind derived electricity. Scotland also has a version of this idea running in the Shetlands, with plans for expansion. Denmark meanwhile is looking to the use of large heat pumps driven by wind electricity, upgrading heat from CHP plants, to feed district heating networks. The Danish District Heating Association claims the initiative could make the Danish heating sector C02 neutral by 2030. www.building4

It could be that Scotland and Denmark could co-evolve viable sustainable energy systems which the rest of us can copy.

Our cities heat up. Urbanization and changes in natural environment, such as substitution of urban vegetation with impervious surfaces, formation of urban canyons and decrease in natural albedo can lead to an increase in urban temperature: the so called urban heat island (UHI) effect (Landsberg, 1981). In summer, the increase in urban temperature affects people with physical and social vulnerability (WHO, 2009) increasing the heat-related mortality (Basu and Samet, 2002). Urban adaptation strategies - such as the increase in urban albedo - can contribute to decrease urban summer temperatures and to prevent from summer weather-related mortality.

Life Cycle Assessment (LCA) is considered a useful tool for decision-makers. However, in its current use, it does not consider the contribution of the interaction between surface albedo and urban environment among the environmental burdens. The variation in albedo is able to affect global climate (i.e., radiative forcing), local climate (i.e., UHI adaptation) and micro-scale (i.e., life cycle inventory of the roofs).

A new study by Tiziana Susca (2012a) proposes an enhancement of the current use of LCA considering a multiscale approach. It includes the evaluation of the potential change in impact on global, meso and micro-scale due to the increase in urban albedo. In particular, the author developed a methodology to include in LCA the effect that the decrease in temperature - due to the citywide albedo - has on human health. The theoretical framework was applied to the case study of the New York City´s rooftops. New York City is plagued by a UHI of about 2°C (Susca et al., 2011) and it is the most populous city in the U.S. This means that the decrease in summer temperature can positively affect a large number of people.

The main aim of the research was to evaluate the contribution of surface albedo in affecting the impact on global climate and on human health. A functional unit of one square meter of white roof was evaluated in the time-horizons of 50 and 100 years. An increase in the urban-wide rooftop albedo from 0.32 to 0.9 - the maximum value that a surface albedo can reach - was proposed. Through the use of an existing climatological model developed by Oleson and colleagues (2010) the mitigation in urban summer temperature in the City was evaluated. The effect on human health was evaluated through the use of both statistical (i.e., life expectancy for different classes of age) and epidemiological data (i.e., risk ratio related to the number of deaths for natural cause in New York City). The mitigation in summer mean temperatures was translated in Disability Adjusted Life Years, the metric that LCA uses for the evaluation of the impact of products, services and goods on human health. The impact on global climate related to the variation in rooftop albedo was calculated through the use of a time-dependent climatological model developed by the same author (Susca, 2012b).

The results of the study show that surface albedo decreases the impact on climate change of one square meter of roof by approximately 84% and on human health of about 3% in a time-frame of 50 years. Besides, in a time-horizon of 100 years the estimation of the effect of surface albedo respectively on global climate and on human health shows a decrease in the impact of 70% and 6%.

The study shows that surface albedo is an important optical characteristic that should be considered in LCA application. Furthermore, the study highlights the importance of the use of a multi-scale approach in LCA that considers the multiple interactions with the urban environment.   


Basu, R. and J. M. Samet. 2002. Relation between elevated ambient temperature and mortality: A review of then epidemiologic evidence. Epidemiologic Reviews 24: 190-202

Landsberg, H. E. 1981. The urban climate. International Research Series, Vol. 28. New York, NY, USA: Academic Press

Oleson, K. W., G. B. Bonan, and J. Feddema. 2010. Effects of white roofs on urban temperature in a global climate model. Geophysical Research Letters 37. doi:10.1029/2009GL042194

Susca, T. 2012a. Multiscale Approach to Life Cycle Assessment Evaluation of the Effect of an Increase in New York City´s Rooftop Albedo on Human Health, Journal of Industrial Ecology, 16 (6), 951-962

Susca, T. 2012b. Enhancement of life cycle assessment methodology to include the effect of surface albedo on climate change: Comparing black and white roofs. Environmental Pollution 163: 48-54

Susca, T., S. R. Gaffin, and G. R. Dell'Osso. 2011. Positive effects of vegetation: Urban heat island and green roofs. Environmental Pollution 159 (8-9): 2119-2126

WHO (World Health Organization). 2009. Protecting health from climate change. Connecting science, policy and people. Accessed May 2011 

UKERC Energy Scenarios

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The UK Energy Research Centre has published a new study on 'The UK Energy System in 2050: comparing low-carbon, resilient scenarios', with reports on new scenario projections for the UK energy system to 2050, comparing them with earlier projections, using the UK MARKAL energy system model.

The existing 'official' scenarios chosen (from DECC, CCC, AEA etc) and the new ones developed by UKERC, are all pretty gloomy- they all contain large nuclear elements, up to 55GW by 2050! In terms of generation, fossil based Carbon Capture and Storage takes second place and renewables, wind and marine energy (wave and tidal) come third, with little biomass or solar use.. Most also only have demand cut by 9-12% by2050.

It's hard to reconcile these scenarios with the plans emerging elsewhere in the EU, in Germany and Denmark for example, which avoid nuclear entirely. UKERC seem to ignore the many zero/low nuclear, near 100% renewables scenarios that have emerged in recent years in the UK and the EU. The most ambitious of UKERC's own new UK scenario has 23GW of nuclear, 23 GW wind plus 12GW of marine energy by 2050

More positively, UKERC uses the exercises to highlight the more immediate issues of new gas expansion and carbon targets, arguing that their analysis reveals 'a strong case for including a maximum carbon intensity target of electricity of 100gCO2/kWh for 2030 in the 2012 Energy Bill'. They say that that it is vital to include a 2030 carbon intensity target in the Energy Bill, because 'without radical decarbonisation of the electricity system by then there is no chance of meeting the 2050 carbon target cost effectively'. They add 'There is considerable gas electricity capacity in both 2030 and 2050 in all scenarios. But in the absence of carbon capture and storage (CCS) this can only be used as back-up for low-carbon sources if the carbon targets are to be met'.

To some extent the high nuclear contribution in the scenarios might be seen as acting as a wake up call., reminding us that a lot needs to be done if we want to avoid that. UKERC say that the UK needs develop and seek to deploy all of the major low-carbon technologies, including nuclear, but they also makes clear 'the absolute importance of energy efficiency and conservation'. pointing out that 'producing low-carbon energy is a costly and politically controversial endeavour, whatever technologies are deployed. The more efficiently it can be used, and the less that is required to satisfy the desired level of energy services, the easier it will be to deliver the necessary low-carbon supply'

They also note that 'there is still considerable uncertainty about the relative current or future costs of the main low-carbon electricity supply technologies - renewables, nuclear, and CCS,' While they claim that 'nuclear appears to be the most economically attractive low-carbon option, ' they admit that is not guaranteed and that 'even the current costs of nuclear in the model are uncertain,' By contrast they say that 'Wind has the present advantage over CCS and nuclear that it can be delivered at scale now, at a known cost, and with known power outputs and carbon emission reductions. Moreover, onshore wind in the best sites is already competitive, or close to competitive, with power generation from fossil fuels. This is currently the lowest cost large-scale low-carbon source of electricity.' Reflecting an earlier UKERC report they add that 'Faster cost reduction of offshore wind than currently assumed in the model could greatly increase its contribution to the 2050 electricity'. Otherwise however, in at least some scenarios, marine renewables (wave and tidal) actually do better than wind long term.

Interestingly they claim that 'new gas-fired stations will be required before 2030 to replace closing coal and nuclear back-up capacity is unlikely to be required before 2030'.However, they say 'there should be substantial efforts to develop electricity storage technologies, in order to reduce the level of back-up gas capacity required'. Well maybe. How much of a role storage can and should play is debatable. As a report on storage from the Energy Futures Lab at Imperial College noted, other balancing options may have the edge. See my earlier Blog

Most of the scenarios the UKERC look at seem to focus mainly on electricity supply, including for heating e.g. via heat pumps, although this is seen as being 'supplemented by biomass and solar thermal,' and Combined Heat and Power gets a mention. In one of the Climate Change Committee's scenarios, CHP supplies about 15% of electricity from 2025 onwards and 20-30% of annual residential heating requirement between 2020 and 2050. The possibility of using the gas grid to carry biomethane or hydrogen is also flagged up, as is the possibility of obtaining 'negative' emissions 'by taking carbon from the atmosphere (through growing the biomass) and then storing this underground when the biomass is burnt'.

Overall however this review of official very conservative scenarios is dominated by the big electricity supply options, with nuclear clearly at the top of the pile and PV at the bottom!

For a very different prognosis, quite apart from the recent Pugwash High Renewables Pathways ( see Shells new global scenario report, which suggests, in its Oceans scenario, that by 2060 solar could supply more energy than any other source, while nuclear's contribution would be very small But that was global. Maybe the UK will buck the trend. That rather depends on the outcome of the current highly contentious negotiations over funding for EDFs proposed new 3.2GW EPR project at Hinkley. It's apparently on knife edge. The recent Energy and Climate Change Select Committee's report 'Building New Nuclear: The Challenges Ahead noted that of this didn't go smoothly, it could be 'difficult (or impossible) to finance any subsequent attempts at nuclear new build'. We should know any day now.

After which it will be the renewables' turn to seek CfD contracts. If the worst comes to the worst, it could be that UKERC will have to develop some new scenarios with nuclear excluded and renewables leading. Perish the thought!

'UKERC report: The UK energy system in 2050: Comparing Low-Carbon, Resilient Scenarios,' UK Energy Research Centre.

Gas and air

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Do we need more gas-fired power plants? The government says so, with talk of 26-37 GW of new gas-powered generating capacity by 2030, maybe over 40 new plants, despite the legally binding target of 80% cut in CO2 emissions on 1990 levels by 2050. And the government has given the go ahead to a restart of shale gas exploration. Although that is not the same thing as supply, and we do not know how much there will actually be available or when, it is clearly seen as part of the way ahead. Energy Secretary Ed Davey said 'Gas will provide a cleaner source of energy than coal, and will ensure we can keep the lights on as increasing amounts of wind and nuclear come online through the 2020s'.However, he didn't sign up to 40 new plants- maybe just 26GW,with a consultation:

We can expect a lot of local opposition to local shale pits! And there has already been some resistance to expanding the use of fossil gas, especially if it doesn't have Carbon Capture and Storage added. For example some argue that biogas (biomethane) produced by anaerobic digestion (AD) of farm and other bio wastes would be a much better bet. In particular, Alan Whitehead, Labour MP for Southampton Test, argues that AD could produce as much energy at less cost and eco impact than shale gas.

However this all assumes that we need a lot of new gas plants, and gas, to back up variable wind. Do we? In 2011, independent consultants Poyry published a report for the governments advisory Committee on the Climate Change with a MAX renewable electricity 2050 scenario (moving to 95% renewables) and said that, by 2050, there might be a need at most for 21GW of fossil backup plant. The recent Pugwash High renewables scenario, which I helped produce, suggested that the use of fossil gas for them could be avoided by using wind-to-gas i.e, synthetic methane produce using excess wind power via hydrogen electrolysis- something now being developed in Germany. However we also found that, when we ran our 70% renewables scenario through the DECC Calculator, there was actually no need for any extra backup capacity by 2050, even when the availability of wind and other variable renewables was low - given the large wind capacity, and the inclusion of demand management (DSM) and some storage, plus 15GW of supergrid links to the continent for imports/ balancing.

We couldn't get to fully 100% renewables, since the DECC calculator would not allow all fossil fuel use to be avoided. It also would not allow the excess electricity from wind to be used to make methane to replace this fossil fuel; it just exported it, when wind was high and demand low. But, if wind to gas was allowed, and worked well, then all the fossil input could be halted and we should have plenty of stored non-fossil gas if any backup was required for a fully 100% scenario.

That might not actually be needed given the supergrid links, although it is possible that we might not always be able to rely on supergrid electricity imports to meet demand at peak times, when wind etc was low, and there may be limits to DSM and storage Hence the possible need for wind to (stored) gas and for gas plants to use it. But perhaps not many, and anyway, not for some time. So, apart from replacements, it looks like we do not need to start a massive expansion of new gas plants or more fossil gas use, at least not now. Or for that matter CCS. What for?

It might be that biomass burning plus carbon capture will emerge as an option (BECCS), which is why some greens do support fossil CCS as an interim step, but it's perhaps not a vital step - at some point we could go straight to BECC and reap the benefits of carbon negative energy production. More immediately, serious attention to energy efficiency would help, keeping demand down. Indeed DECC have talked in terms of 40% reduction in some sectors by 2030, whuch is the level we chose in our Pugwash scenario

Further ahead, the Environmental Change Institute at Oxford University, has outlined a strategy for energy use in buildings through which the 477 TWh of gas and oil and 200 TWh of electricity currently consumed in the sector was reduced to a demand for 100 TWh of renewable electricity supplied by the grid by 2050.

That may not of course reduce peak demands enough, but there are many more ideas for demand management which could:

It is true that, as existing gas plants get old, and coal and old nuclear plants shut down, we will need some CCGT replacements, and a bit of expansion, although Poyry said not till after 2030 for peaking plant. But by then the plants could mostly use green gas. And in fact many of them could be CHP plants, linked to district heating networks and buffer heat stores, providing a variable mix of heat and power. That would enable the more effective balancing of variable renewables- when wind is high heat would be stored and when wind is low, more electricity than heat would be produced.

DECC sometimes says that demand will double, which seems to be used to justify new nuclear and assumes a switch to the use of electricity for heating. But they also argue that we need to plan for more gas/CCGT now, to start to take up the slack due to the slower than expected deployment of new nuclear and (some say) renewables. Put that way, what really matters is not the backup argument, although if Poyry are wrong and our Pugwash calculations are also wrong, that does add to the problem longer term. But, leaving new nuclear aside (as a potential non starter), what is more important now is to get renewables, and efficiency, to take up the slack.

Germany, with a quite poor renewables resource, is showing how it can be done, so surely we can, with the best wind, wave and tidal resource in Europe. It is true that, as happened with the first 'dash for gas' in the UK in the 1980s/90s, switching from coal to gas/CCGT does cut emissions (by about 40%/kWh), but the risk is that a new dash for gas would be just another delay and deflection from getting serious about renewables.

So it all comes down to how quickly we want to, and can, expand renewables. We have not done well so far. Embarrassingly so, compared to nearly every other country in the EU, except Malta and Luxembourg. While the leaders have got to 30-40% of total energy, we are at 4%.

Some of them have to benefit of large hydro, but even so, that surely is not a reason for us to look to using more gas. After all we have a gigantic offshore wind resource, and one of the few signs of progress in the UK is that we are learning to develop it.

The cost of energy

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In a report on Deploying Renewables, the International Energy Agency says that 'a portfolio of renewable energy technologies is becoming cost-competitive in an increasingly broad range of circumstances, in some cases providing investment opportunities without the need for specific economic support'. It includes established hydro, geothermal and bioenergy technologies in the list. It adds that 'cost reductions in critical technologies, such as wind and solar, are set to continue,'.

In its study of UK energy options, consultants Mott MacDonald came up with the following cost estimates.

Generation cost estimates per MWh delivered, in the UK levelised costs in £/MWh

Electricity Option Current cost (Cost in 2040)
On-shore wind 83-90 (52-55)
Off-shore wind 169 (69-82)
Tidal Barrage 518 (271-312)
Tidal stream 293 (100-140)
Wave (fixed) 368 (115-140)
(floating) 600 (200-300)
Hydro (small/run of river) 69 (52-58)
Photovoltaics (PV) 343-378 (60-90)
Biomass (Wastes/SRC) 100-171 (100-150)
Biogas (AD/wastes) 51-73 (45-70)
Geothermal 159 (80)
Nuclear (PWR/BWR) 96-98 (51-66)
Gas-CCS 100-105 (100-105)
Coal-CCS 145-158 (130)

The above data is mostly taken from the executive summary (e.g. Fig 2, for current costs), but higher and lower estimates are also offered (in Chapters 3 and 7) based on differing assumptions e.g. about progress down learning curves

Mott MacDonald (2011) 'Costs of low-carbon technologies' report for the Committee of Climate Change, May,

As can be seen, on-shore wind comes out as the cheapest option now, but by 2020 and 2040, its cost range largely overlaps with those of solar PV and nuclear. But by then some of the other renewables also begin to overlap at the bottom of their cost ranges.

These long-term estimates are very speculative: most of the renewables are moving down their learning curves rapidly, PV especially, with many now predicting that it will soon reach grid price parity in some locations. For example, Consultancy firm McKinsley says that PV prices will reach grid-parity with coal and nuclear as soon as 2020.

The European Wind Energy Association has predicted that offshore wind will get down to €75 /MWh (i.e. about £63/MWh) by 2020. The Carbon Trust says that, although on initial commercial deployment, tidal energy could cost £160/MWh and wave energy £400/MWh, by 2025 the cost of both wave and tidal stream power could be brought down to £150/MWh, and that with continued targeted innovation, 'the UK's best marine energy sites could generate electricity at costs comparable with nuclear and onshore wind', by 2025. Carbon Trust (2011) 'Accelerating marine energy' Carbon Trust report CTC797,

These estimates do not include any costs associated with the intermittency of the supply from variable renewables. However it can be argued that these should be relatively small, even for large contributions, around £2.5/MWh for contributions to supply of up to around 20%, and up to £7/MWh for a 40% contribution.

While some, like the CCC, put it higher, the actual cost will depends on what measures are taken to ensure balancing and some of these (e.g. building supergrid links) could have large net cost saving benefits for the system as a whole- e.g. as the Pugwash High Renewables scenario noted, the UK could earn up to around £15bn p.a by exporting excess green power when UK demand was low and wind power high.

On balance then some renewables are already competitive with nuclear and most could be competitive with projected nuclear costs by 2040. Then again the nuclear estimates are speculative. The estimated cost of the Flamanville EPR is now put at €8.5bn, up from its initial €3.2bn, but that is the first (or rather second) of its kind (the first, in Finland, now looks likely to be 9 years late). The industry says they will do better later on e.g. with EDF proposed plant at Hinkley. Even, so Mott MacDonalds figure look very optimistic. Indeed, they admitted that they may have been 'bullish' about nuclear costs, using industry estimates. They also ignore the extra cost of proving more reserve back up capacity that would be needed to insure against down time if nuclear power use was expanded.

A simple minded conclusion on costs is that, firstly we don't know for sure, but secondly that there may not be much in it by 2040. In which case other factors may be more important in deciding which options to back. Safety is one, carbon emissions are another. On safety it is hard to see how renewables, large hydro apart, could have anywhere near the potential health impacts of nuclear/kWh produced, with safety issues, driven by public concern, being one reason for the high cost of nuclear. Safety issues can be extended to include security issues, and again it is hard to see how renewables face anything like the direct security threats (e.g. the risk of potential for terrorist attacks) associated with nuclear, large hydro and possibly large CSP desert solar arrays apart, and certainly none of them would contribute to the proliferation of weapons making capacity.

On emissions, most renewables have zero or very low direct CO2 emissions, as does nuclear, but nuclear plants need fuel, the production of which involves the use of energy, this at present being mined and processed using energy from fossil fuel. The result is that, although the nuclear fuel cycle generates on average around 15 times less carbon dioxide than coal plants, it generates about 7 times more than modern wind turbines. Moreover, this imbalance is likely to get worse as reserves of high grade uranium dwindle (it will take more energy to process lower grade ores) and as renewables like wind become more energy efficient. B. Sovacool 'Valuing the greenhouse emissions from nuclear power'. Energy Policy 36 (2008) pp2940-2953).

Nuclear fuel could be processed using non-fossil (nuclear or renewable) energy, but the costs would still rise as the ore grade used diminished to the point ultimately when it became futile, and it would in any case be an odd way to use renewable energy i,e. to create nuclear waste to store for centuries.

In the short term cost are strongly influenced by current financial arrangements, investment cost and so on. For example under the UK Renewables Obligation: on-land wind projects get £92/MWh, offshore wind farms £135/ MWh , solar PV £160/ MWh. It has been claimed that the UK's proposed new nuclear projects will need a subsidy of at least £95-105/MWh, but more likely £120/MWh and possibly up to £165/MWh, with long contracts. On this basis nuclear looks a very poor choice. However, the nuclear lobby claims its costs will fall as new technology emerges, but so does the renewables lobby. As argued above, it may be that both will be right, in which case costs should not be the main issue long term. But short term, well any day now we should hear what CfD strike price the government will offer EDF for the proposed Hinkley EPR. Around £100/MWh for 40 years seems likely- more than for on-land wind. Plus other concessions. All adding to our bills...