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June 2013 Archives

The report on the Severn tidal barrage from the Select Committee on Energy and Climate Change concluded that the proposal for a £25bn privately funded barrage from Hafren Power was not convincing and lacked detail. Hafren Power had 'failed to overcome the serious environmental concerns that have been raised' and had 'failed to reassure the ports industry that its business would continue to be viable with a barrage in place'. It went on 'while a tidal barrage could offer decarbonisation and energy security benefits, the Hafren Power project in its current form has not demonstrated sufficient value as a low-carbon energy source to override regional and environmental concerns. Alternative pathways exist to meeting our 2050 carbon targets.' It added 'Alternative options for exploiting Severn tidal resources also exist' and it looked at some of them briefly, including the 250-350MW Swansea Lagoon proposal, the 600 MW 'Stepping Stones' Lagoon put forward by Parsons Brinckerhoff /Black & Veatch, and also Rupert Armstrong's 6GW Tidal Reef concept.

The committee felt that 'a more incremental approach using alternative technologies (such as tidal lagoons) may have the potential to provide a lower-risk, lower-impact option than the Hafren Power barrage scheme', although they added 'whether these alternatives offer better value for money is far from clear at this stage'. An incremental 'step by step' approach would reduce the risks associated with going for a large barrage and allow for gradual learning. So they recommend that 'consideration is given to first developing a smaller scale tidal project, in order to build a stronger evidence base for assessing impacts, risks and costs before proceeding with any larger scale scheme'.

That is pretty much what consultants Black & Veatch and Parsons Brinckerhoff had told them in their evidence. Similarly the Renewable Energy Association had expressed concerns about the 'financial and environmental risks' of a large-scale barrage and advocated building a small barrage to begin with, 'to assess the costs and monitor the environmental impact'.

The Committee noted that the Regen SW and South West Marine Energy Park discussion paper, "Bristol Channel Energy - A Balanced Technology Approach", had claimed that a combination of tidal, wave and wind technologies could provide up to 14 GW of low-carbon electricity, obviating the need for a 'single mega-project which has major economic and environmental and impacts'. The paper also suggested that the focus on a single, 'potentially divisive' barrage project is damaging for the marine industry and instead recommends 'a more inclusive discussion'.

The alternative options certainly did look worth exploring. Tidal resource modeling by the Energy Technologies Institute suggested that 'the energy yield from a single large-scale Severn barrage could be achieved with a lower level of interaction and impacts through a combination of tidal energy extraction at a number of smaller, different sites.' By contrast, Engineering the Future told them that, with a single barrage, 'the timing of energy production would vary with the tides and the amount of power generated would vary significantly between spring and neap tides. Even though there are engineering possibilities to hold back and control water flow through impoundments, there would be some days every month when electricity was produced at times when ordinarily demand would be very low'.

On the economic case for the large barrage, the committee felt that 'attracting very large sums of money from long-term investors may prove challenging' and that, with DECC estimating levelised costs at £214-£353/MWh, the CfD strike price for the barrage 'would have to be considerably higher than the £100/MWh which Hafren Power have "in mind". Furthermore, the company say they would require this price to be guaranteed for 30 years, twice as long as an offshore wind project. [...] As a minimum, the strike price for barrage-generated electricity should not be higher than that for offshore wind, which is expected to be around £100/MWh by 2020 [...] If a higher strike price was offered, it would risk swamping the Levy Control Framework to the detriment of other low-carbon technologies'.

The Committee also noted that the environmental impacts of the current Hafren barrage plan were 'very considerable and that there is a high risk of unintended and possibly damaging consequences'. For example Hafren Power proposed to use a Very-Low-Head (VLH) turbine design deploying two sets of contra-rotating blades. Generation would be bi-directional on both the ebb and flood tides. The Committee noted that the Environment Agency had claims that it was 'not aware of any turbine designs which would allow the safe, repeated passage of fish through a barrage at the scale proposed.'

It noted Prof. Falconers estimates were that the scheme 'would reduce tidal range in the Severn from its current range of 0m to 14m to one of 3m to 12m. Low tide would therefore be raised by 3m, and high tide would be reduced by 2m. The overall reduction in tidal range would lead to a reduction in intertidal habitats of salt marsh and mudflats, with a resultant impact on bird populations dependent on these areas for feeding grounds.'

RSPB had suggested a barrage would have 'significant adverse effects on the populations of 30 species' with potential 'serious effects on a total of 96 European protected sites for birds'. The Countryside Council for Wales said that : 'Decreased flows and flow speeds incurred by a barrage would reduce the suspended sediment concentration within the impounded area and downstream leading to further changes in the estuary extent and composition of intertidal and subtidal habitat features of the Severn Estuary'

While Hafren Power cited the La Rance scheme as evidence of the potential for improved biodiversity with a barrage in place, the Committee was also told that La Rance was not an appropriate comparator for the Severn 'since it is "a rocky river valley" unlike the sediment-rich Severn estuary'. Problems experienced at the Annapolis Royal site in the Bay of Fundy had include 'fish mortality, erosion problems downstream and the health of the river upstream'. It was reported that tidal causeways across tributaries there had led to 'rapid, unpredictable consequences and no foreseeable return to a state of dynamic equilibrium.' RSPB pointed to experience in the Eastern Scheldt, where a storm surge barrier was built in the 1980s; the estuary still shows 'absolutely no sign of reaching a new equilibrium'.

By contrast the Committee noted that with lagoons the environmental impact was thought to be less since they would not affect tides and water flow to the same extent and would not obstruct downstream and upstream migration of fish. In addition 'Land-connected lagoons are located away from navigation channels, and therefore are unlikely to impact on the operations of Severnside ports. A lagoon design would be unlikely to impede the development of other marine technologies in the region.' They noted that the Regen SW and SW Marine Energy Park discussion paper suggested that a fixed barrage would 'impact on downstream flow and hence tidal stream generation potential'.

Hafren were clearly not happy and the door is still open for them to come back with an improved proposal, but overall it doesn't sound very promising or likely. Energy Secretary Ed Davey told the Lib Dem conference in Cardiff earlier this year that the government was 'looking for private-sector consortium to come with different projects in the Severn', but on the Hafren project he commented 'I think it's fair to say their numbers aren't in the place that they would need to be and there are some questions I know people have of that proposals yet to be fully answered.' By contrast, he said that there had been a 'huge amount of work' done independently on 'alternatives to a straight barrage, with lagoons and a more displaced, dispersed approach to getting that powerful tide and I think there are some real attractions to that. I am hoping that maybe if people can work through those economics, work through the ecological aspects which are critical, they can present government with proposals that are affordable and attractive'.

Select Committee report:

In my previous Blog I looked at the role of hydro power, which dominates in many developing countries and regions, supplying nearly 100% of electricity in Albania, Angola, Bhutan, Burundi, Costa Rica, D R Congo, Lesotho, Mozambique, Nepal, Paraguay, Tajikistan and Zambia, as well 60-90% in 30 other developing countries.

However, as I indicated, there are concerns that, given a range of environmental, social and political issues, large hydro may not be the best option for the future, whereas smaller scale projects, including micro hydro, wind and PV solar, might be better suited to development goals and local needs.

I focused on Africa, but the dominance of hydro is even greater in South America. Brazil, the leading economy in the region, already gets 87% of its electricity from renewables, mostly hydro. However it is trying to diversify, with wind and solar. So are some of the less developed countries in the region. Nearly 100% of Paraguay's electricity comes from hydro, but it is trying to expand other renewables, as are Patagonia, Bolivia and Ecuador, with PV especially favoured. Colombia, which currently gets 70% of its electricity from hydro, is investing in wind power: it has an estimated theoretical wind power potential of 21 GW.

It is the same story elsewhere. 82% of oil-rich Venezuela's electricity already comes from renewables, primarily hydro, but there are plans for expansion of wind power (with 10GW or more being said to be possible) and a 'sowing light' PV programme. Peru gets 56% of its electricity from hydro and is trying to build up its wind, solar and biomass contributions via a feed in tariff system. Argentina, which gets 40% of its electricity from hydro, is building a 1,350 MW wind farm with Chinese turbines, and is also pushing ahead with PV solar. In Chile, an election campaign promise by President Piñera was to get 20% of energy demand met from renewables by 2020. Uruguay plans to produce 90% of its electricity from renewables by 2015, 30% from wind, 45% hydro, and biomass 15%.

Moving north, Mexico, already has 2GWof wind capacity and is a looking to 12GW by 2020. There are also some interesting new wave and tidal projects emerging. It aims to get 35% of its electricity from non-fossil sources by 2026, up from 20% now. Nicaragua aims to be 94% renewables based by 2017, using hydro and some wind. In the Dominican Republic, a 2007 law established tax breaks for investment in renewables, which account for 14% of electrical generation. Cuba has been slower off the mark but there are many local off-grid PV projects, as well as hydro, wind and biomass resources, while solar and wind are obvious areas for development in the Caribbean region generally, with some projects underway or planned.

While funding remains an issue in much of Central America and the Caribbean, the solar and wind resources are large, as they are across the whole South American region. Large still hydro dominates but the use of wind is spreading, as is PV, although more slowly while the potential for using biomass, although controversial, is very large. But that's another story!

There is no question that the use of some types of biomass for energy is likely to be a poor choice. Some energy crops used for liquid biofuel production have very low calorific value, and mono-cultural plantations can be very bad for biodiversity, as well as requiring a lot of water and undermining local ecosystems. Rapid expansion of biofuels production in the developing world has led to problems such as deforestation and displacement of indigenous people. The need to meet rising biofuel targets has also led to exploitation of workers, loss of wildlife and higher food prices. It also contributed to poor harvests, commodity speculation and high oil prices, which raised the cost of fertilisers and transport.

However much of this is related to commercial pressures for production and export of high added value vehicle fuels- there have certainly been reports of poor working conditions in some biofuel plantations in Asia. Biofuels are the ultimate cash crop. But if we move away from high added-value products like biofuels for transport, the situation may get a little easier. Biomass can also be used for heat and power. Indeed many argue this make more sense, since the final energy yields/acre using solid woody biomass are generally higher than for liquid biofuel production.

In particular, there may be a role for some high yield energy non-food crops on marginal land, and for less invasive approaches, such as short rotation coppicing. Forests are different matter. It seems clear that deforestation and unsustainable exports should be avoided and that attention should be given to other less damaging approaches to biomass sourcing. Clearly though there is still much to debate, and some environmentalists see biomass and not too dissimilar from large hydro-something we should avoid. I will be looking at that debate some more in my next Blog.

For the moment, it maybe worth noting that the World Bank recently reversed a two-decade old decision to turn its back on large hydropower investment, which it now sees as crucial to meet the bank's key development goals, claiming that it has the highest potential for clean energy development and was abundant in the poorest regions of the world where the needs are greatest. It has pledged $1 billion in funding for hydro projects in relevant countries. Overall, it aims to place hydro higher on the political agenda, including large-scale projects, arguing that hydro at all scales was vital in affecting the impact of climate change.

This view is not shared by many environmental groups, who see large hydro as not only massively disruptive, in terms of local social and environmental impact, but also as unlikely to help with balanced sustainable development, with most of the power being sent long distances rather than being used locally, and methane emissions from biomass coming down stream and trapped by the dam making large hydro projects in some hot heavily vegetated areas worse in terms of greenhouse gas production than coal fired plants of the same generation capacity. Micro/mini hydro is preferred as less invasive and more localised. In addition to wind, PV solar is also seen as important for developing regions, including South America. See

Renewable Energy World has been running a useful series of reports on PV's prospects in the region

While it is true that in some locations hydropower, and the storage capacity associated with reservoirs, may be useful to help manage the variability of some these renewables, in the development context, there is a risk that large hydro projects will continue to dominate, squeezing out often more appropriate smaller scale options. For example, Brazil's 3,750 MW Jirau hydropower plant is the largest single renewable energy project so far being supported under the Kyoto Clean Development Mechanism.

Hydro- and beyond

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Hydro plants are the largest existing renewable source of electricity, with around 874 GW installed world-wide, providing almost all of the electricity for many developing countries, for example (in 2008) nearly 100% in Albania, Angola, Bhutan, Burundi, Costa Rica, D R Congo, Lesotho, Mozambique, Nepal, Paraguay, Tajikistan and Zambia, as well 60-90% in 30 other developing countries. In addition it provides nearly all the electricity in Norway, most of it in Iceland, and up to 60% in Austria, Canada New Zealand and Sweden.

Since the energy output is dependent fundamentally on the head height, sites which can accommodate taller dams can produce more energy and it is a square law: double the head gives you four times more energy on average. So in energy terms at least, the bigger the better, and trapping a large mass of water in the reservoir behind the dam will help to give a guaranteed supply, although there will be cost trade-off and site limitations.

The energy source is ultimately solar heat, which drives the hydrological cycle, but since that is climate and weather related, the energy resource at any particular location and time can vary. Indeed, with decreased rainfall in some areas in recent years, output from some hydro plants has fallen. This is likely to get worse with climate change.

The interactions between hydro projects and the environment are also two-way: large projects can have significant environmental impacts. Many environmental/development organisations, while backing smaller scale hydro, have opposed large hydro projects because of the large social and environmental impacts.

The social dislocation resulting from flooding areas for new reservoirs is an obvious issue, but there are also wider ecological issues. For example, the World Commission on Dams NGO has claimed that, in some hot climates, biomass carried down stream can be collected by the dam and can rot, generating methane, so that net greenhouse emissions can be more than from a fossil plant of the same energy capacity. It is not just a matter of any initial biomass trapped when the hydro reservoir was first filled, but a continuous ongoing process of fresh biomass decay,

The industry does not accept this. It says emissions are not a general problem, and in any case there are remedial options and there remains a strong push for more hydro, and large schemes. http//

While it is clear that Africa and other places in the developing world need energy, there are counterviews about whether hydro, especially large hydro, is the best bet. Large projects are expensive and involve large companies who, some fear, may not be that concerned about local impacts. Certainly there have been some bitter battles fought over some projects and large-scale hydro remains a politically contentious issue in many parts of the world. Quite apart from local impact issues, it is sometimes argued that large centralised projects may in any case be the wrong answer for Africa and other similar locations. The very large distances involved make it unlikely that grids could ever cover the entire continent. As with the 40GW Grand Inga project on the Congo, much of the electricity seems likely to be exported on HVDC links to remote markets, not used locally. Local decentralised power may make more sense. That can be micro hydro, or wind, or biomass or solar, technologies which can be installed quickly with low local impacts and a potential for direct local involvement, and also possibly for the creation of local manufacturing enterprises to build the equipment.

Large hydro obviously plays a major role in Egypt, the Aswan Dam supplying 10% of its electricity, although it is now diversifying into solar and wind, with a target of getting 20% of its electricity from renewables by 2020. Large hydro is dominant in many sub-Saharan African countries, but in addition to wind, micro-hydro is seen as attractive in some locations, while village-level PV projects have spread widely, for example in Uganda, Tanzania, Chad, Rwanda, Angola, Gambia and Congo. Niger aims to get 10% of its primary energy from renewables by 2020, Senegal 15% by 2025. Kenya has large wind, solar and biomass resources, and is planning a 100 MW wave plant. It already has over 200 MW of geothermal capacity, and aims to meet 50% of its electricity needs with geothermal by 2018. Nigeria's 2006 Renewable Energy Master plan has renewables supplying 13% of electricity in the short term, and 36% long term. Ghana has introduced a Feed-In Tariff for PV, and its 155 MW PV project, launched in 2012, is the largest so far in Africa

Renewable energy feed-in tariffs (REFiTs) are clearly helping roll-out renewable technology across Africa, as they have in the EU, but a recent NGO report argued that, to meet Africa's needs at the speed and scale required without burdening the energy poor, costs must be distributed across the population fairly, based on usage and ability to pay, while the international community can provide extra financial support, such as through 'top-up' payments via a Global REFiT Fund, in line with obligations under the UNFCCC/Kyoto protocol for repayment of climate debts.

There has certainly been no shortage of high-level initiatives on renewables in the region. In 2009, the Africa-EU Energy Partnership and the EU, together with the African Union, launched a 10 year Renewable Energy Cooperation Programme. and the UN's new Sustainable Energy for All initiative, includes €50m EU backing. But Africa needs more than top-down aid programmes. It needs local involvement, training and skill development, to support the growth of local jobs, and technical and economic capacities.

For a good overview see IRENA's new report on Renewables in Africa:

In my next Blog, I will be looking at the situation in South America, where large hydro also dominates, but alternatives are also emerging.