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Renewable Energy in the UK:
A NATTA Guide for Newcomers

Brief Introductory Guides to the basic options and state of play in the UK, provided by NATTA,the UK based Network for Alternative Technology and Technology Assessment.

The items above are based on NATTA leaflets which are availaible free from NATTA c/o EERU, Open University, Milton Keynes, MK 7 6AA

NATTA also offers a range of more detailed publications on renewable energy, including its bimonthy journal RENEW. See RENEW ON-LINE for regular extracts.

NATTA is an independent membership network with some 500 subscribers, based with the OU Energy and Environment Research Unit. As with all NATTA publications, the views expressed should not be taken to necessarily reflect those of all NATTA members, The Energy and Environment Research Unit or the Open University.


UK Renewable Energy Options:
A Brief Overview

Renewable energy is so called because it relies on natural energy flows and sources in the environment, which, since they are continuously replenished, will never run out. The UK is well placed: it has amongst the world's largest resources of wind, wave and tidal energy.

Wind turbines sited in windy parts of the countryside could in principle generate perhaps 20% of the UK's electricity, while the potential for wind turbines mounted in shallow water off-shore is even larger - perhaps up to 50% of UK electricity requirements, although the cost would be higher than for on-land machines. Typical large modern wind turbines have a rated output (at full power) of 1000 - 2000 kilowatts. They are usually grouped together in `wind farms'.

Wind moving over water creates waves, and the UK wave energy potential, if suitable floating devices could be located in deep water out to sea, (i.e. `deep-sea' systems) could be up to 20% or more of UK electricity requirements. Smaller amounts of power, at possibly less cost, could be obtained from devices operated nearer to the shore, (`in-shore' or `coastal' systems) and from shore mounted units e.g. sited in gullies, (`on-shore' systems).

The gravitational pull of the moon and the sun on the seas, produces two tides per day as the earth rotates. The high tides can be trapped behind a `barrage' on suitable estuaries, creating a head of water which, when released, can be used to drive turbines, as with low head hydro-electric plants. Like some existing hydro schemes, some tidal barrages might be large. For example, the scheme proposed for the Severn Estuary would have around 8000 megawatts of installed generating capacity and could supply 6% of UK electricity requirements. The total UK tidal barrage potential is around 20% of UK electricity requirements.

In addition, the fast moving tidal streams in some areas (e.g. around Scotland and the Channel Islands) can also be used to generate power, using propeller type devices located in the flow. If all suitable tidal stream sites were used, they might provide up to 19% of UK electricity requirements.

More conventionally, although the energy potential is relatively limited, electricity can be generated form the flow of rivers and even streams, via small low head /'run of the river' hydro electric turbines, as well as via the more familiar and larger hydro electric dams; with their construction costs now paid off, the latter produce the cheapest electricity in the UK.

In addition to these electricity supplying options, the UK has, surprisingly, a significant solar energy potential, the currently most cost-effective way of exploiting it being via well insulated `passive solar' houses, designed with large south facing windows to trap solar heat.

Solar energy can also be converted into electricity via the photovoltaic `solar cell' , and solar energy is of course the key power source for plant (and animal) life via photosynthesis. The harvesting of `energy crops' looks increasingly likely to provide a significant source of `bio-fuels' of various sorts - liquids (like ethanol and bio-diesel) for transport use, and gases (like methane), or solids (eg wood) used for heating or electricity production.

Short rotation 'coppicing' of rapid growing willow or poplar is one option, with the resultant wood chips being converted in a gasifier plant to produce hot gasses, which in turn are used to drive electricity-producing gas and steam turbines. This could become a major new energy source.

Some industrial and domestic wastes can also be used also be used as fuel , although there has been some concern expressed by environmentalists over emissions from waste combustion plants, and not everyone would see waste as strictly 'renewable'.

Similarly, collecting heat from `geothermal' sources deep underground is not strictly renewable - the geothermal wells would be gradually exhausted. But the energy potential is quite large - perhaps 10% of UK electricity requirement from `hot dry rock' deep underground.

The UK already obtains about 2% of its electricity from renewable sources, chiefly from large to medium scale hydro-electric plants. There is some potential for expansion of medium and small scale hydro, but wind and waste projects are now being developed around the country on a significant scale and energy crops seen as the next likely area for development. The Government has however relegated offshore wind, wave and tidal energy to the long shot categeory, on the basis of cost, although it would seems unlikely, given the UK's maritime history and extensive offshore engineering expertise, for these quite considerable energy resources to be ignored indefinitely.

Potential Contributions

The Department of Trade and Industry's 1994 Energy Paper 62 (DTI 1994), estimated that, in principle, electricity producing renewables might economically supply up to a maximum of 190 TWh/yr by 2025, or around 63% of current consumption. This is the resource at around 4.5 p/kWh at 15% discount rate.
This however is the maximum practical resource and in reality there would be a range of technical, environmental and economic constraints on what could actually be achieved in practice. A fairly conservative, mid range estimate, adopted by the UK Governments Renewable Energy Advisory Group, was a 20% contribution to electricity by 2025 (60 TWh/yr) involving around 10, 000 MW (net) of renewable generating capacity.

By way of comparison, the UK has around 65,000 MW of conventional electricity generating capacity. Less than a third of the UK's electricity now comes from coal fired plants, over a third now comes from natural gas fired combined cycled gas turbines. The nuclear element provides around 25% of UK electricity supply, although as the older plants reach the end of their operating life, this will progressively fall. Now that the bulk of the nuclear industry is privatised, it seems unlikely that any new nuclear plants will be ordered in the UK

It seems likely that renewable energy technology will continue to develop in terms of performance and reliability, and become more cost effective. For example the costs of electricity from wind turbines has fallen by around 70% within a decade or so, and similar reductions for photo voltaic solar cells have taken place.

However, there are obviously some technical constraints. Some renewable energy sources of course are intermittent e.g. the winds and waves, and of course, the sun! However it has been suggested that intermittency need not be a major operational problem, if the electricity from these devices is fed into the national power grid network. So long as the total contribution from the various intermittent renewables does not exceed around 30-40% of the total electricity on the grid, the grid can in effect 'even out ' local variations, so that the net overall power available from the grid remains more or less constant, without the need for expensive storage systems..

Although renewables generally have much less environmental impact than conventional sources, no technology can be totally benign, and they have varying degree of local impact. The development of some renewable energy technologies is therefore also likely to be constrained by local environmental, planning and land use factors. Indeed there have already been some local planning disputes and local opposition in relation to the spread of wind farms in the UK: see 'the Windpower Debate in the UK'.

Equally however, the deployment of renewables may be stimulated by increasing environmental concerns over the generally much more significant global impacts of using conventional energy technologies e.g. global warming from the emission of greenhouse gases like carbon dioxide produced when fossil fuels are burnt. The local and global impacts have to be traded off against each other.

Conclusions

Obviously the future of renewables will depend on a wide range of technical, economic, environmental and political factors , as well as other policy concerns and political developments, nationally and internationally. Some of the key issues are the question of whether nuclear power can be relied on in the future, the security of supply and balance of payment problems that may face the UK when and if it has to import natural gas from overseas, the role of energy conservation, and the wider environmental issues relating to greenhouse gas emissions, acid rain and so on.

The UK is fortunate in having relatively large reserves of oil, gas and coal, and this, and the relative cheapness of gas, has, arguably, led to a degree of complacency, not least on energy conservation. But, quite apart from the fact that these fossil fuel reserves are finite, the question remains whether all of them can be used without producing unacceptable environmental problems, most notably in terms of global warming. New technologies are emerging which use fossil fuels more efficiently, thus reducing net emissions.

Obviously in the short term energy conservation and the potential for energy saving via the introduction of more energy -efficient energy -using technology would merit top priority. After all, cost effective savings of between 50-80% are claimed as feasible in many end-use sectors, and it would seem to be foolish to consider any new supply options unless we were also tackling energy waste. However, although much can be done to avoid energy waste, the UK will still need new sources of energy, as old plant is retired. Given that nuclear power seems unlikely to revive in the UK at least, the renewable energy based technologies represent the most promising non -fossil options.


Renew, NATTA's bimonthly 30 page newsletter, will keep you up to date on developments. See RENEW ON-LINE for regular extracts.

As with all NATTA publications the views expressed in this briefing should not necessarily be taken to reflect those of EERU or of the Open University.

Return to index


The Windfarm Debate

The Pro's and Con's of Windfarm

The UK's potential resource for wind generated electricity, using windturbines sited in windy parts of the countryside, is put at about 20% of current electricity requirements. That's about what nuclear power provides at present.

However the amount of power that can actually be obtained form the winds will depend on how many acceptable sites can be found. Currently more than thirty windfarms - groups of windturbines on one site - have been set up, in Cornwall, Wales, Yorkshire, Scotland and else where. Most have been welcomed locally, but in some locations there have been some strong local protests, chiefly over noise problems and visual intrusion.

The Case for Wind Farms is straight forward. Windpower is clean - extracting power from the wind produces no chemical or radioactive emissions, and has minimal physical impacts on the local ecosystem. The land around the windturbines in windfarms can be used for conventional agricultural purposes- indeed sheep seem to welcome them as windbreaks.

Birds tend to avoid moving windturbine blades: indeed they seem much more at risk from the large national grid cables. Windturbines are more like bird scarers.

When and if needed, decommissioning is easy: when removed, windfarms leave no toxic residues or environmental damage. There are no direct fuel costs, and the cost of extracting power is bound to fall as the technology improves.

In summary, windpower is sustainable, clean and is increasingly competitive economically. Its local impacts are relatively small compared with the global impacts of using conventional fuels.

But there is also a case against windfarms.

Firstly, the local impacts are not always insignificant- local residents may be disturbed by noise and the windfarms intrude on the landscape. Some local residents have reported annoying levels of noise from the blades or the gearing systems of some windturbines - with some, for example, finding it hard to sleep. Others have complained that the machines are ugly, and may deter tourists from the area. Some objectors feel the planning bodies have not been sufficiently rigorous in applying the necessary planning controls.

Secondly, some say that the wind programme is counterproductive- it would be better to invest in energy conservation. Some opponents feel that the wind farms produce expensive electricity and that the developers have simply taken advantage of the interim cross subsidy scheme introduced by the Government to make easy profits, paid for by consumers, whereas the amount of power generated is small compared to what could be saved if we invested instead in energy conservation measures.

Finally, some say that the UK is too densely populated to be able to absorb a significant number of wind farms. Wind farms must inevitably be sited on prominent ridges and hills, and these are usually in attractive areas. These should be protected for everyones use. If we must have windturbines, why not put them off shore?

In summary, wind farms are noisy, ugly, expensive and are not needed or appropriate in the UK countryside.

Discussion

With the foregoing in mind, it seems useful to make the following points.

Firstly, the economics of windpower are improving, but profit margins are still tight. Even so the extra cost to consumers is small.

The Governments Non Fossil Fuel Obligation (NFFO) initially provided a protected market for both nuclear power and some renewables, together with a surcharge on fossil fuel generation. This fossil fuel levy was passed on ultimately to consumers, and ran at around 10% of generating costs until 1998. It raised 1.3 billion or so each year , 1.2 billion of this going to Nuclear . The small amount left over has supported just under 200 renewable projects, including 30 or so windfarms. The cost to the consumer of supporting the wind projects was very small - less than one percent extra on their bills.

The nuclear part of the NFFO was withdrawn in 1998, and since then the cost of electricity from wind projects has continued to reduce, as the technology has improved. So the next wave of wind projects have been able to go ahead with less subsidy, and windpower is approaching commercial competitiveness.

Even so, the profit margins for bold new projects like this are tight: it is hardly a case of easy money for the developers and backers.

The NFFO system is now being replaced with a Renewables Obligation - which will require electricity suppliers to work towards obtaining 5%of their power from renewable sources by 2003 and 10% by 2010. Wind power is likely to meet a significant part of this requirement. That’s not surprising since some of the latest projects are generating at prices competitive with conventional sources- at around 2p/kWh in some cases.

Secondly, the initial projects were generally welcomed locally - with some of the initial objectors changing their mind once the projects were up an running. This pattern of initial concern followed by general acceptance has continued

The UK's first windfarm was at Deli farm near Delabole in Cornwall. An independent 'before and after' study indicated that 80% of the local people asked said it made no difference to their daily life, 44% approved and 40% approved strongly. In the 'before' study, 40% of local people interviewed thought it was going to be visually intrusive, but this fell to 29% after it was set up and running. Whereas many expected it to present noise problems beforehand, after it was running 80% felt this had turned out not to be a problem. The windfarm had 100,000 visitors in its first year of operation.

A subsequent Countryside Council for Wales study, in areas of Wales where windfarms have been operating, indicated that 68% of the sample felt that the windfarms had little impact and that they would be prepared to see more. Interestingly many more objections came from a control sample in an area where there were no windfarms.

And a recent study in Scotland, focusing on people living near Scotlands first four windfarms also found that the closer people lived to windfarms the more positive was their attitude to them. 67% found 'something they liked' about the Scottish wind farms, rising to 73% amongst those living closest. Moreover, 74% found 'nothing they disliked' rising to 80% for those nearest. Overall it seems that peoples worries prior to construction were often unfounded - for example 40% of the 430 or so respondents in the Scottish survey said they though that there would be a problems, but in the event only 9% reported any problems. Specifically, before hand 12% though noise would be a problem, but afterward only 1% reported any disturbance.

Thirdly, the main objections have been about projects where there have been specific local problems.

The LLandinam windfarm in Wales is acceptably quiet close up,

(most people are surprised at how quiet windfarms are when they first visit them) but down in the valley resonance effects seem occasionally to amplify the noise. Effects like this will have to be responded to carefully, and avoided in future. Similarly, as experience with windfarm deployment grows, siting policy can be improved to avoid interfering with sensitive local views. Full local consultation, well in advance, is an obvious priority.

Fourthly, around 70% of the 3000 or so wind turbines in Denmark are owned locally- would local ownership reduce the level of opposition in the UK? 'Your own pigs don't smell' say the Danes.

So far all the UK projects have been developed by conventional medium to large scale companies, with some of the funding and the technology coming from overseas eg from Japan. Would a shift to 'co-ops', like the Danish Guilds, improve the situation in the UK, with the local community thereby benefiting directly from the project?

Fifthly, the UK has the worlds best wind power resource- with Scotland having more windpower available than the rest of Europe put together.

Denmark, which is mainly flat, aims to generate 10% of its electricity from wind turbines by 2005. Surely the UK which has a much better wind regime, can do at least as well?

If we turn our back on this option, what are the alternatives?

Energy conservation is an obvious priority, but even if we can block up the leaky bucket of current very inefficient energy use system, we will still need sustainable energy supplies to fill it. i.e. we need both conservation and renewables- including offshore wind and the other renewables.

Its worth noting in this context that installing 1500 Mega watts of renewable generating capacity would, according to the DTI's 1994 Energy Paper 62, avoid the emission of some 2 Million tonnes of Carbon pa, at a cost of around only one percent extra on consumers electricity bills, via the NFFO. By comparison the Energy Saving Trusts energy conservation programme, if successful, would save around 2.5 mTCpa and add 1-2% to consumers bills- possibly more. So renewables and conservation are fairly evenly matched in terms of the cost of cutting emissions, with wind power playing a useful role in this process.

Finally, we are not faced with a static situation. As wind turbine technology develops, some of the initial problems should be resolved. For example, new, variable speed, machines are being developed which are more efficient, economic and less noisy.

The Wind Farm Debate

The debate over windpower has become increasingly polarised in the UK, with extreme positions often being taken, particularly by the objectors, who sometimes evidently feel that windprojects are being forced on them.

One unsigned leaflet circulated in Wales in 1993 warned that Wales was 'being covered in swathes of ugly turbines to line the pockets of foreigners and greedy owners' . A little more moderately, Sir Bernard Ingham, vice president of the Country Guardian anti-wind lobby group, commented 'people who think they're attractive are aesthetically dead'. (Newsweek 28 March,1994).

Clearly everyone is entitled to their opinion.: after all, in the end it is often a subjective issue. For example, some people are very sensitive to low level noise- and can't sleep with a fridge running. Some are very sensitive to changes in the landscape- even though of course the current UK landscape is mostly man made, the result of centuries of modifications due to agriculture, land clearance and so on.

Some find windfarms very appealing- as witness the large number of tourists visiting them. Some local people have actually objected to not being able to see them.

Some see them ugly monstrosities, as 'lavatory brushes in the sky', while other see than as symbols of a sustainable future, and as a clear alternative to nuclear power.

Given the wide range of responses to the windfarm issue, it is understandable that the debate can become a little shrill. However, what is needed is a constructive debate on the role of renewables generally, and on exactly what the carrying capacity of a country like the UK is as far as windturbines are concerned. Is the 20% theoretical resource too much to hope for? Will it be cut down in practice to 10% or even less? What about offshore wind? And the other renewables? What would be their impacts? For example, would short rotation arable coppicing be a better bet, more suited than wind farms to farming communities, as some suggest? Or, if carried out on a large scale, wouldn't that be to return to a ' slash and burn' approach, with its own set of environmental dangers? Aren't there likely to be just as many objections to extensive coppice plantations, wood chip incineration plants, and significantly increased local truck traffic?

Conclusion

All technologies have impacts. In general, however, the impacts of the renewables are much smaller and more local than the usually large and global impacts of

conventional energy technologies. Inevitably, the land based renewables, like wind turbines and energy crops, are likely to be the most problematic. By contrast, by the nature of their location. offshore wind for example, as well as offshore wave and tidal stream turbines, are less likely to present problems of visual intrusion- they also offer very large energy potentials. Unfortunately however, very little funding has been made available for research on wave and tidal stream technology, but a small offshore wind farm has been installed off the coast of Northumbria, and offshore wind seems likely to become a major option for the future.

However, even given a properly integrated national policy on renewable development, we would still probably have to strike a balance between these various options, and, therefore, to get to grips with land use issue.

Hopefully, however, the smaller scale and more local nature of most renewable energy technologies should make this process easier. For unlike conventional power stations, whose often large scale, global, social and environmental costs and risks are often hidden away, the impact of renewables like windfarms is more obvious and local. Basically, the technologies are easier to understand and assess. What you see is what you get: there are no hidden costs.

Given that the nature and function of the technology is more transparent, it ought to be possible to have a constructive debate, involving a wide range of people, over how, where, on what scale and by whom renewable energy systems like windfarms should be developed.


NATTA produces a bi-monthly journal, Renew, which, amongst other things, covers the windfarm debate. Coverage of the debate has been brought together in four compilations from back issues of RENEW- 'Windpower in the UK', Vols 1,2,3 & 4, (1993 ,1995, 1997, and 1999; respectively) 1&2 are 2 pounds each , 3&4 are four pounds each. See also Sue Walkers NATTA report on the LLandinam windfarm, 'Down on the Windfarm' (2 pounds). The windfarm debate is also discussed in John Glover and Peter Daley's NATTA report 'The UK Windfarm Debate' (5 pounds).

In 1988 NATTA published what has become one of the classic reports on this subject 'Windfarm Location and Environmental Impact' by Alexi Clarke (10 pounds).

More recently Dave Elliott produced a paper on 'Public Reactions to Windfarms', which is also available from NATTA (5 pounds).

Our most recent publications in this area are Dave Tokes ‘ Communiy Ownership: the only way ahead for UK windpower?’ ( 3 pounds) and ‘Local Renewables’ NATTA Conference report ( ten pounds) , both of which look at the case for local ownership of wind projects.

Renew, NATTA's bimonthly 30 page newsletter, will keep you up to date on developments. See RENEW ON-LINE for regular extracts.

NATTA is an independent national information network based with the OU Energy and Environment Research Unit As with all NATTA publications the views expressed in this briefing should not necessarily be taken to reflect those of  EERU or of the Open University.

NATTA c/o Energy and Environment Research Unit, Open University, Milton Keynes, MK7 6AA.


Water Power

Of all the elements, water can produce the most dramatic effects on the environment- whether it's floods, rainstorms, or tidal waves. There is obviously a lot of power there. Where does it come from?

Solar Power

Most of it comes, one way or another, from the sun. The suns heat evaporates off moisture to form clouds, then rain falls, some of it ending up in rivers and streams. And we can use this hydrological cycle -by damning up rivers and streams to produce useful heads of water. That's the basis of hydroelectric power- the mass of water trapped behind a huge damn is passed through a turbine, generating electricity. Its cheap and clean, and the energy source will last for ever-its renewable. And it can be used on a small scale as well as on the more familiar large scale.

Currently about 20% of the worlds electricity is generated by hydro plants-so in reality renewable energy has already arrived.
But there is another way in which solar energy can provide us with power via water- wave power. Waves are created by the action of wind over water, the winds in turn being the result of the differential heating of different parts of the land and sea by the sun. In fact waves are really a form of stored wind power.
We can harness the power of the waves by absorbing the energy in giant floating devices- like the nodding duck developed by Stephen Salter at the University of Edinburgh, or the squeezed airbag 'Clam' system developed at Coventry University.
The potential is vast- perhaps 20% of the UK's electricity could be generated in this way, maybe more. The UK initially pioneered wave energy, but Norway and Japan took over the lead following a disputed decision by the UK Government to wind up the UK wave Research Programme. Some smaller inshore and coastal units have been developed, but for the moment the large scale development of wavepower is stalled..

Lunar Power

The other main way in which water can be used to provide power is by the use of the tides. Tidal energy shouldn't be confused with wave power: the energy comes from the gravitational pull of the moon which attracts masses of water to create tidal rises and falls., as the earth rotate, modified by the pull of the sun and the shape of the landmass.
Again the potential is huge- perhaps 20% of the UKs electricity requirements, with the Severn Estuary being one of the worlds best sites. Of course, given that we are talking about large civil engineering structures across estuaries there will be some local environmental impacts. But the Tidal Barrage on the Rance estuary in Brittany has been operating for more than twenty years with few problems.....

Taken together the UKs water power resources-hydro, large and small;wave , deep sea and inshore; and tidal power, could ultimately provide a large proportion of the power we need-and on an indefinitely sustainable basis. Obviously there will and should be debates about the environmental trade offs that might have to be made eg in the case of tidal barrages and large hydro plants, but many of our water power sources can be developed on a smaller scale basis. There are already many dozens of new micro-hydro schemes in operation or under construction and there are scores of potential sites for smaller scale tidal barrages.
At present the economics tends to favour larger schemes, but when and if we begin to take the environmental costs of existing forms of power generation into account, it seems likely that most types and scales of water power, will increasingly be seen as viable.

For further discussion of the issues see the following reports:
'Wave Energy' (A compliation of reports from back issues of NATTA's journal Renew), 1994, (2 pounds) from NATTA.
'The UK's Wave Energy R&D Programme' Dave Elliott (A critical review of the way in which wave power development has been constrained in the UK), OU Technology Policy Group report, 1995, (4 pounds) from NATTA.
'Tidal Power', NATTA report, 1990, (1 pound) from NATTA.
'Tidal Energy', (A compliation of reports from back issues of Renew), 1994, (1pound)from NATTA.


Renew, NATTA's bimonthly 30 page newsletter, will keep you up to date on developments. See RENEW ON-LINE for regular extracts.

As with all NATTA publications the views expressed in this briefing should not necessarily be taken to reflect those of EERU or of the Open University.

Return to index


Solar Power in the UK

The sun provides the basis for life on earth and delivers sufficient energy to each square foot to meet all our needs -if we could tap that energy efficiently. Historically human beings have tried to do that via agriculture, using wood as a fuel and by using the indirect solar energy represented by winds and streams More recently we've used the stored solar energy of fossil fuels-coal, oil and gas. But it may be that we can make use of the sun more directly.

Around the world recent years have seen large scale experiments with solar power- for example via giant solar heat concentrating mirrors and dishes, tracking the sun across the sky and focusing its rays so as to raise stream for electricity generation. Large scale 'Solar Thermal 'plants like this are becoming increasingly popular in desert areas of the USA. and elsewhere.

But solar energy can also be utilised on a smaller scale - and even in cooler climates like the UK.

Solar Britain

At first glance you would not think that solar power stood much of a chance in the UK, what with our short summers and cloudy days. But the UK receives on average over the year around half the amount of energy from the sun per square foot as countries on the equator, and that heat is likely to be of more use here than in hot countries.

During the 1970's there was something of a boom in sales of roof mounted solar collectors in the UK That was hardly surprising, since flat plate solar heat collectors, looking something like a radiator, plugged into a hot water system, could typically cut domestic fuel bills by a half. But it soon became apparent that the overall economics were not that attractive-commercial systems had payback times of five to ten years or more, and there were also some cowboys operating in the field who undermined consumers confidence. The boom consequently faded, although many enthusiasts continued with diy units.

The 1980's saw something of a renewal of interest, following the oil price shocks. Local councils made much of the running- with rehab council houses being retrofitted with solar assisted heating and several new solar council house projects were initiated. By the end of the Greater London Council's reign in London for example there were more than 200 solar houses in use, and, meanwhile, Milton Keynes Development Corporation was turning the new city of Milton Keynes into a solar showplace, with more than 300 solar housing projects.

However, the emphasis had gradually shifted away from flat plate solar collectors on individual houses. One of the last of the Greater London Council supported schemes was a grouped heating scheme, with an array of solar collectors feeding a common hot water store, shared by 15 separate dwellings. This system averaged out variation in use rates for each house and improved the overall economics.

More fundamentally, there was a switch to the even more cost effective passive solar concept. Conventional Roof top solar collectors need small pumps to drive the heated water around the heat circuit, but you can also collect useful amounts of heat, if you have large south facing glazed areas. Its much like the greenhouse concept- and involves no moving parts. Hence the term 'passive' as opposed to conventional 'active' solar collectors, with pumps.

Typically, with a well insulated house, you can cut overall fuel bills annually by a third in this way. Milton Keynes has two hundred or so passive solar council houses, and passive solar design has now become almost a byword in modern architectural practice. Large scale solar atriums for office and commercial buildings are now a familiar sight, and, at the more lowly level, many people have added solar heat trapping conservatories to their homes.

Slowly Does It.

So slowly solar power is becoming a reality in the UK. It has been a slow process in the main because solar power has had to compete unaided against often heavily subsidised conventional fuels-like electricity and gas. Only the more environmentally conscious homeowners have opted for solar out of commitment to a sustainable future. But the balance is slowly tipping, and new techniques and technologies are emerging which could well bring about more radical changes.

Already there are more efficient, although more expensive, evacuated tube solar collectors, as well as various clever new selective absorption systems to improve heat collection

But the big breakthrough is likely to be in the photo voltaic solar field. Photo cells, like those on cameras and pocket calculators, convert sunlight directly into electricity. The only problem is that they are expensive. They were initially used mainly for powering space satellites, but developments in the semiconductor field have gradually brought prices down. Within a decade or so they are likely to be competitive with conventional power sources.

In which case we are likely to see photo voltaic ('pv') cells being used widely- even for domestic supplies. They are already in use in some outlying rural areas where there is no grid electricity and the alternative is diesel, or nothing, in the Australian outback, in dessert areas and in African villages, for water pumping, running fridges for key medical supplies, or powering remote telecommunications equipment.

Soon we may see much wider scale use. New types of cell materials have been developed which are more efficient and cheaper and some can be mounted on flexible backings, so it may even be possible to buy electricity generating sheets to hang up wherever you want.

Ten Wasted Years?


Even if you discount this sort of development, one way or another the potential of solar energy would seem to be considerable. But, as we've seen, it has been a long time coming. at least in the UK. The UK Government has until recently been pretty dismissive of its potential. Photo voltaics have been seen as pretty much irrelevant to the UK and in 1982 the Government decided to abandon further support for active solar projects. Only passive solar continued to receive support, while a few UK companies, like BP, continued to push ahead with pv for the export market.

However recently there has been something of a U -turn, following a report which concluded that there might soon be a very significant market for pv. Certainly the USA, Japan and more recently Germany, have been putting billions into pv in recent years..

Environmental Impacts

One of the reasons why at least some people have not seen solar as a viable option for the UK is that it has been seen as a very land hungry technology. There has been talk of having to cover the whole of the UK with solar cells in order to generate any significant power. The reality is very different For example, the potential for using roof tops and walls for solar cells is very large: and pv cells can be used as cladding material, thus reducing some building costs and offsetting the cost of the cells. There is already a house (in Oxford) equipped in this way and an office building at the University of Northumbria in Newcastle upon Tyne.

Prof Bob Hill at the University of Northumbria has been carrying out aerial photography to identify suitable south facing surfaces around the UK and in London, and he has pointed out that a similar study done in Berlin estimated that the city could generate 2.5 GW of pv power - equivalent to two nuclear power plants. London is likely to have a similar potential, while the potential for the UK as a whole, if fully developed, might be greater than the total UK electricity requirement.

Of course that still begs the question of the economics. But environmentally, there would seem to be few problems, at least in terms of the uses of pv. There are however some question marks associated with the manufacture of pv cells. This is very much a high tech industry using exotic and often hazardous chemicals-potentially representing a significant health and safety problem for workers. There could also be ex-plant pollution issues to contend with. But assuming these potential problems can be avoided, pv could become the breakthrough technology of the next decade.

What next?

The photoelectric effect, on which pv cells are based, was first explained by none other than Albert Einstein, at about the same time as he developed his famous E=MC 2 equation, which lay the basis for nuclear energy. At one time, it was felt that solar cells were going to be a much more likely contender as power generators than nuclear energy. But then came the wartime Manhattan atom bomb project and one way or another, solar cell research lost out. It has only been in recent decades that interest has returned.

For the enthusiasts, the future could be one in which not only is pv used widely in the north, but third world countries in the sunny south use electricity from vast solar cell arrays in desert areas to generate hydrogen gas by splitting water into its constituent part via electrolysis. The desert nations, many of them currently locked into oil production, could then become a major exporter of a new form of less damaging energy to the cold north.

Certainly there is growing interest in the use of hydrogen as a fuel to replace petrol, and in photo voltaics as a power source for producing the hydrogen -pvh is the buzzword. The attractions are clear: hydrogen can be burnt with no byproduts other than water, it can be used in a fuel cell to generate electricity, again very cleanly, and you can store hydrogen easily, and thereby avoid one of the key problems with all form of solar energy- its intermittancy.

Solar hydrogen, and hydrogen generated from indirect solar sources, like the winds and waves, could be piped down the gas main for domestic use, perhaps mixed in with our progressively diminishing north sea gas reserves. It could become the heating fuel of the future. And used directly as a fuel, or with fuel cells in electric cars, it could help us deal with the pollution problems of petrol engines.

If these sorts of projects, and others like them, get off the ground, we could be moving towards a future in which the sun plays a major role in helping us live once again in a sustainable way.

NATTA has produced a short guide to Milton Keynes' Solar Houses 'Solar in the City',(50p ) and a booklet 'Solar Houses in London' (1 pound) .
There is also a compilation of solar articles, 'Solar Energy', culled from back issues of NATTA's journal, RENEW. -60p.
All these publications are available from NATTA C/O EERU, Open University ,Walton Hall, Milton Keynes, Bucks MK76AA


Renew, NATTA's bimonthly 30 page newsletter, will keep you up to date on developments. See RENEW ON-LINE for regular extracts.

As with all NATTA publications the views expressed in this briefing should not necessarily be taken to reflect those of EERU or of the Open University.

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Energy Crops

Growing fuel rather than food could well become a significant new option for farmers - especially given the European Union's land set aside policy. Liquid biofuels (biodiesel) are already being produced in some parts of the EU from oil seed rape. Solid fuels from `woody biomass' are another option. Short rotation arable coppicing, e.g. using fast growing willows or poplar is currently seen as likely to be an important source of fuel for electricity generation in the UK - indeed the UK Governments Department of Trade and Industry estimated (in Energy Paper 62) that the maximum total realistic UK resource potential by 2025 could be up to 150TWh/yr - half current UK electricity requirements.

At first sight increased afforestation would seem a very attractive proposition - trees are beautiful and we need more to help combat global warming. But large scale short rotation arable coppicing does not involve full tree development - instead the thin willowy growths, reaching perhaps 15 feet, are cut back to stumps every 3-5 years. That may not prove to be so visually attractive.

Large areas could also be involved with mechanised cutters passing periodically along corridors through the coppice plantations. The resultant wood chips would also have to be transported periodically to combustion plants - with traffic, and its associated pollution, in rural areas therefore perhaps increasing. And combustion itself can involve pollution.

Overall then, as with all technologies, even renewable energy based technologies, there are environmental trade offs.

The Case for Coppicing

Existing forms of power generation are very environmentally damaging. Burning coal, oil and gas inevitably produces carbon dioxide, a key greenhouse gas, as well as other pollutants, including acid rain related gasses. Nuclear power generation inevitably involves the generation of highly dangerous and very long lived nuclear wastes, and there is the risk of major accidents.

By contrast, growing and burning energy crops is greenhouse gas neutral, as long as the regrowth rate balances the use rate so that as much carbon dioxide is absorbed as is produced by combustion. Regularly coppiced plantations will actually absorb more carbon dioxide than mature trees - since carbon dioxide absorption slows once a tree nears maturity.
All the existing fuels will eventually run out, whereas wood is renewable - it can always be available.

The UK's reserves of north sea oil and gas are limited, and even our coal reserves will not last for ever. Used in the current types of nuclear reactors, the worlds uranium reserves will only last around 60 years. Perhaps more importantly the cost of using these fuels will increase as stricter environmental control are applied.
By contrast arable coppicing represents a very large new energy resource - which can be sustainably harvested, at reasonable cost, and costs should drop as more experience is gained.
In summary energy crops are sustainable, environmentally sound, and represent a huge new energy source.

The Case Against Coppicing

The local impacts may be significant - depending on the scale.

  • The coppice plantations may not be very visually appealing.
    It is envisaged that large parts of the set aside land - representing 15% of UK arable land - might be used, and that could change the character of the UK landscape. Fertilizer and Pesticide run off could also be a problem. As could the risk of fire.
  • Wood chips are a bulky fuel and there could also be local environment impacts from the extra truck traffic (and its pollution).
  • Combustion is environmentally undesirable.
    Burning wood produces toxic pollutants - including, possibly, dioxins from chemical residues from herbicides and pesticides.
  • Focusing on single crops can undermine biodiversity.
    Monoculture plantations are aesthetically unappealing (as with the vast existing conifer plantations). Being less ecologically diverse than, for example, natural forests, they tend to be at risk of disease and pests, so herbicides and pesticides may have to be used to compensate.
  • Farming should be for food - not energy.
    With much of the world starving, it is immoral to switch to a new energy cash-crop in order to fuel our wasteful energy habits. Energy conservation would be a better bet - and is a cheaper option. So far coppicing seems unlikely to be economic without subsidy although equally it could become a vast new extension of agri-business.

  • In summary, there are environmental, social and economic question marks.

    Discussion

    With the foregoing in mind, it seems useful to make the following points: Only a few experimental projects exist at present - and rapid expansion would take some time.
    Coppicing would initially have to be subsidised from the EU's set aside scheme, the woodland development grant scheme and via the NFFO `fossil fuel levy' ( as is likely to happen under the third NFFO order from Nov 1994 onwards) and it could take some years to become established on a wide scale.
    So there is time to discuss the pro's and con's.

  • Arable coppicing is one of several renewable options with land use implications: wind farms are another example.
    Each of the renewables have their advantages and disadvantages. For example, some might argue that coppicing is more suited to the UK landscape than wind farms, although the best sites for coppicing are usually not the best sites for windturbines and vica versa. Others might feel that what is to some extent a `slash and burn' energy cropping approach is a backward step, although global hunger is a problem of distribution and local politics. We already produce enough food to feed the world.
  • Even so, we need to decide on the right balance between the various renewable options and energy conservation.
  • In technical terms, energy coppicing can be very efficient.
    The energy ratio (i.e. available energy output in the crop divided by the energy input requirement, for growing, harvesting and transport) has been put at between 10 and 100. And the combustion process can be very efficient, especially given the development of advanced co-generation/CHP techniques. For example with gassified biomass used to power steam injected turbines (the so called BIG-STIG technology), operated in the combined heat and power mode, conversion efficiencies of up to 80% can be obtained.
  • The environmental impacts can be limited - and some can be positive.
    Herbicides would only be used in the first year of the cycle. Less pesticides would be needed than for conventional arable crops and coppices tend to mop up pollutants, thus reducing 'run off' into water courses. Coppices would be located mainly on marginal land, and can offer habitats eg for birds and insects, especially given the open access corridors that would traverse the plantations. Bio-diversity can also be ensured by using multi-cloned plants or by mixing species: coppices have already been shown to attract woodland animal species. Overall, if degraded or abandoned cropland were used, the environmental and wildlife impact would be positive.
  • The Transport Impact will be low
    Wood chips would be stored on site and probably be transported annually for combustion. For say a 10 hectare coppice plantation, with 5 hectares harvested annually, only 75 tonnes of wood chip would need transporting annually. This would involve 4X20 tonne loads or 8X10 tonnes loads - not a huge annual volume. And it would replace the transport of the crops that might have been grown otherwise.
  • Conversion into electricity could be done locally.
    The combustion plants could be on local industrial estates. A 10 MWe unit run continuously at 80% efficiency would require around 60 tonnes of wood chip per day i.e. 3X20 tonne lorry loads per day. It would be unlikely for wood chips to be transported more than 20 miles. And there are prospects for power generation on the farm site itself, thus eliminating transport requirements almost entirely. Either way, local employment would be boosted. Initial studies indicate broad support.
  • A study of the attitudes of country users for ETSU in 1993 indicated that although there were some reservations, in general, there was support for coppicing, as long as the scale was not too great. Some concern was however expressed at leaving its development up to commercial pressures and interests.

    Conclusion

    On balance arable coppicing seems to offer significant advantages. However, there are clearly some unknowns: what exactly are the environmental and pollution implications, how economic will it be, how will it be planned, what scale is appropriate? Is it just an extension of conventional farming or something new?
    Currently, no change of use application need to be sought for switching set aside or arable land to coppicing. At the very least, some form of planning control would seem necessary to avoid land use conflicts and visual disruption. Existing planning rules and emission standards would presumably cover the processing and combustion plants: but an integrated planning approach to the whole system seems called for, with full local consultation and detailed guidelines, as have been developed in the USA and elsewhere. More generally, there would seem a need for a debate over renewable energy development generally. At present the pattern of development has been left primarily to short term market forces to define - with the emphasis being on waste combustion and wind farms, arable coppicing being the next major commercial contender. All have environmental impacts - even if they are much smaller than the global impacts of conventional energy systems. They may have a place in a sustainable energy system, but the correct balance is as yet unclear. As is the fate of some of the larger-scale renewables, most of which, although currently seen as more expensive, have very low environmental impacts - e.g. off-shore wind and deep-sea wave. At present these are receiving no support in the UK. This could be short-sighted, given that environmental concerns e.g. over global warming, may grow. The debate over coppicing should therefore not be carried out in isolation from the broader debate over our energy future.

    The debate on coppicing.

    Large scale coppicing is a new concept which the Government clearly favours. The National Farmers Union is also strongly in favour of coppicing - sensing a new opportunity for its members. Clearly employment is a key issue. The environmental and strategic debate has, however, only just started.
    NATTA has produced a compilation of reports on the Energy Crops and Biofuels from its bi-monthly journal RENEW: 'Energy Crops' (2pounds), available from NATTA, c/o Energy and Environment Research Unit, Open University, Milton Keynes, MK7 6AA

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