De-carbonising the future

Dave Elliott

(Energy and Environment Research Unit, Open University) is a founder member of SERA Energy Group. He is Professor of Technology Policy at the Open University and is Director of the OU Energy and Environment Research Unit. He is editor of RENEW, a journal covering renewable energy policy.

One of the main causes of Climate Change is the emission of carbon dioxide gas from power plants. We've expanded our use of fossil fuels dramatically since the industrial revolution: Slide 1. We are around half way through the process of burning off the fossil fuel reserves. Unsurprisingly, the levels of carbon dioxide in the atmosphere have risen: see slide 2. And it seems this is linked to the rise in average global surface temperatures;slide 3. By 2100 there could be a 6 degree rise, according to the latest IPCC report.

The only way to avoid carbon emissions is either to try to capture, and then store, the carbon dioxide once it's produced, or more fundamentally, deal with the problem at sources and avoid burning fossil fuels entirely. There is of course a 'half way house' option- switch over to more efficient energy generation and energy using systems. Then the amount of carbon dioxide produced for supplying energy at the point of use can bereduced: slide 4 I'll deal with these options in turn. Please note I'm focusing on power stations and not cars, which are another large source of emissions, although some of my comments have relevance to ways of reducing emissionsfrom them.

1. Conservation

Firstly, let's start at home and look at using energy efficiently. The potential for the more efficient use of power in domestic heating and power using devices is very large. We could fairly easily cut energy waste by 20%. The same is true in other sectors. Indeed industry has done very well over the years and cut waste by nearly 40% since the 1970's- primarily because that has saved them money, an obvious motivation as fuel has become more expensive. It's vital that we invest in efficient use of energy-if for no other reason because it makes us competitive. But there are limits to how much we can improve efficiency- once all the easy and cheap options have been exhausted. And however much we spend on end-use efficiency improvements we will still need some power. Where will this come from?

2. CHP/CCGT

Can't we reduce emissions by developing more efficient ways to generate power from fossil fuels? The answer is yes, to some extent. Conventional large coal fired plants waste two thirds of the energy content of the fuel they burn - it is dumped into the environment from the giant cooling towers. About half of this wasted energy can in fact be reclaimed and used for heating nearby buildings, schools, offices and so on. That's done widely elsewhere in Europe, but not in the UK. Basically coal was seen as cheap, and so efficiency didn't matter. But operating in the so-called Combined Heat and Power, or CHP, mode, using the heat as well as the electricity, doubles the efficiency of fuel use. Or to put it the other way around, you can get the same amount of total energy from half the fuel. CHP is at last being developed in the UK, but not for city wide district heating using coal. Instead smaller scale gas fired units are being installed. The governments target is for there to be 10GW of CHP in place by 2010- in effect saving nearly 5GW's worth of fossil fuel use.

Worthwhile as this is, the power industry has mostly preferred another option- switching over to combined cycle gas turbines, without CHP. The reason was that they are cheap to run and quick to install- essentially jet engines in a shed. And of course gas is cheap. It was purely fortuitous that burning gas in these plants also produces about 40% less carbon dioxide per kWh of energy produced than burning coal. But the result of switching over from burning coal to the burning gas to generate electricity, has been that the UK has been able to reduce its carbon dioxide emissions in line with the international targets agreed following the Rio Earth Summit in 1992, without having to do anything else. The scale of this dash for gas is remarkable- whereas 80% of the UKs electricity used to come from burning coal, now its down to 28%, and gas provides 39% and rising. However, there is a limit to how many more coal fired plants can be replaced by gas plants- so the growth in emissions savings will tail off. And as demand for power increases, as seems likely, then we will once again see our emissions increase: slide 5. There are also limits to gas reserves- north sea gas won't last for ever, and importing gas from Russia (as is the current plan) has serious implication for security of supply. So the dash for gas is only a temporary solution to reducing emissions.

3. Sequestration

What about trying to remove the carbon dioxide from power plant emissions? It can be done, but it's very expensive, especially given the bulk of the gasses involved. Leaving aside fanciful ideas such as freezing and storing it as dry ice, one more credible idea is to pump it into the empty reservoirs created by gas and oil extraction e.g. under the north sea. Another, cheaper, idea is to grow more trees to absorb carbon dioxide.

However each idea has the same major drawback- none can be relied on to tie up, or 'sequester', the carbon dioxide indefinitely. Trees die and rot, or burn in forest fires, releasing the carbon dioxide again. Underground strata can shift and release trapped gases.

4. Non Fossil Fuels

Really, we have to think about not producing carbon dioxide in the first place. What are the non-fossil fuel options?

Firstly there's nuclear power. At present the world obtains around 6% of its primary energy from this source, but it has been suggested that this could be expanded as a response to climate change. However there would be major problems. I used to work in the nuclear industry, so it gives me no pleasure to report that it has not turned out to be cheap, clean and safe, as we once hoped. For example, on cost, when an attempt was made to privatise the UK's nuclear plants in 1990, it became clear that they were not commercially viable. A non fossil fuel tax was invented to meet the extra costs over fossil fuel generation, and put around 10% on consumers fuel bills -although to be fair, a small part of the fossil fuel levy, initially 2%, did of course go to support some renewable projects. But for nuclear, generation costs, in the private sector context, of around 6p/kWh have made it unviable compared with gas- at less than half of that figure.

Add to that the massive public unease over the risks of accidents, and its not surprising that no new nuclear plants have been ordered in the USA since Three Mile Island accident in 1986, and that most of W. Europe backed away from nuclear following the Chernobyl disaster in the Ukraine in 1987. Deaths are still ongoing from that- and may reach more than 50,000 eventually. Some countries like Denmark had already decided not to go down the nuclear route. Others like Italy, Sweden and more recently (with the election of a red-green government) Germany, decide to phase out their nuclear plants. The UK has a policy of 'diminishing reliance'. Given that no new plants are planned, that too amounts out a phase out. Even France, the one time mainstay of the European nuclear industry, has imposed a moratorium on new projects- following the election of its red-green government.

It is true that some countries in Asia are considering new nuclear plants-notably Japan and China-and that the ex-Soviet countries still have to rely on their sometimes rather suspect nuclear plants. But otherwise nuclear powers fortunes look bleak. See slide 6.

Unless, that is, it can be redeemed and relaunched as a solution to climate change. My view, and that of SERA's, is that this would be disastrous. Why try to solve one global environmental problem by creating another- radioactive pollution? There is still no solution in sight to the growing problem of nuclear waste storage. We have no idea what to do with it long term- when long term means millennia. In this situation it would be irresponsible to expand nuclear power. And that's leaving aside the issue of proliferation and diversion of weapons making material.

There is talk of new nuclear technology that might be safer - but that wouldn't resolve the waste or proliferation issues. In the longer term, there's the nuclear fusion option- but that too would produce irradiated materials which would have to be stored. In any case, fusion is a long shot, unlikely to be available in time to help us deal with the urgent problem of climate change.

Renewables

Fortunately - if my last category of solution can be followed up successfully-we may not need to, in effect, create little suns on earth with fission or fusion reactors. We have a working fusion reactor that already supplies all the energy we need, if we can learn how to tap it efficiently-namely the sun.

Current best estimates suggest that by 2050 or so, around 50% of the worlds total energy could be coming from renewable sources - wind, wave, tidal, hydro, solar, biomass- and geothermal. Slide 7. The last few decades have seen the use of so called renewable energy sources expanding rapidly- for example, starting from nothing, there is now 14,000 megawatts of wind power generating capacity in operation around the word. That's more that all the current UK nuclear plants. It's the fastest growing new energy technology, and prices are now competitive with conventional generation in some locations. Germany leads the wind boom, the USA is second, followed by Spain and Denmark, but with India and China catching up fast. The UK is well behind- despite having the EU largest wind resource by far.

Sadly it's the same story across the board. The EU recently issued proposed targets for the member states to aim for, set against the current level of renewable energy contributions. The UK came out near the bottom in both classes. Whereas Austria generates around 72% of its electricity from renewable sources, Sweden 49% and Portugal 38%, the UK can muster less than 2% And our much vaunted target of 10% by 2010 is the lowest in Europe- apart from Belgium and Luxembourg. Slide 8 shows the picture in terms of total energy use- again we are at the bottom of the league table.

Much of this is to do with the legacy of low or negligible funding for renewables in the UK by the previous administration. In the 1970's Labour launched an ambitious renewable energy programme (at least by the standards of that time) only to see it be frittered away. The wave energy programme was axed. We lost the lead in wind. The geothermal programme was abandoned. So was the tidal programme. Solar was also sidelined.

We are now back at the starting gate, having wasted nearly 20 years. The new Labour government has increased the R&D budget for renewables, which had a fallen to a pitiful £11m pa. Not enough yet- we'd like to see it rise to at least £50m pa. But we are glad to see that Labour has reduced VAT on renewable energy equipment to 5%- thus for example cutting the costs of installing solar energy to houses by 12.5%. On the larger scale, it is about to impose a Climate Change levy on the business use of energy, with power from renewables exempted. And it has proposed a Renewable Obligation on electricity suppliers requiring them to source 5% of their power from renewables by 2003, and 10% by 2010.

SERA welcomes these moves. But more is needed if we are to meet the targets. The private sector has to respond. Its good to see that Shell and BP have both committed themselves to PV solar and that Powergen and Shell are supporting offshore wind- that is where the big energy resource lies. In principle the UK could obtain all its energy from wind turbines located the north sea. But we won't need to. There also a huge offshore wave resource and a large offshore tidal current resource. As a maritime nation, with extensive offshore engineering expertise, it would be insane for us not to exploit these options fully. And back on land, there is the energy crop option, using the set aside land to good advantage. With farmers finding it hard to survive in the food market, perhaps some could diversify into energy crops- for electricity generation and for vehicle fuel. (I could add that, rather than incinerating them, we could also get vehicle fuels from municipal waste).

As I hope I've indicated, the renewable energy options are very tempting. Prices are falling as new technology develops and world markets for the new technologies are expanding rapidly. SERA is not alone in believing this to be the way ahead for energy supply. Slide 9 It will involve a shift to smaller scale generation, nearer to the centres of demand, even right down to the local level. Using local sources to meet local needs can avoid looses in long distance transmission. But at the same time there will be a need for larger units- offshore wind farms, wave and tidal current energy arrays, perhaps even tidal barrages.

Large projects like this can of course have environmental impacts- as we have seen with large hydro. So there will be plenty to discuss when it comes to choosing the right mix. Indeed as the backlash against some wind projects in the UK has shown, acting locally and thinking globally is not always easy.

Inevitably then, there are going to be many problems ahead, as with all new technologies. Renewable sources are diffuse and some are intermittent which implies a need for some form of energy storage. For the moment, with only small amounts of power from variable sources feeding in to the grid, that is not a problem. Local variations average out. But in the longer term, if renewables are to contribute substantially, then we will have to consider, for example, switching over to using electricity from renewables for the production of hydrogen gas by electrolysis. Unlike electricity, it can be stored and then distributed, down the existing gas mains, to the point of use, where it can be converted to electricity when needed, in fuel cells. Or used as a fuel direct for heating, or, of course, in cars.

A shift to the hydrogen economy? Science fiction stuff you may say, but I've just refereed a paper from Japan proposing just that - a new gas grid covering NE Asia fed with hydrogen, mixed in with methane, derived from local wind and geothermal sources. Slide 10. Meanwhile there's an ambitious plan (Slide 11) for a giant 2. 2 GW 'tidal fence 'containing hundreds of tidal current turbines mounted in a causeway between islands in the Philippines- part of what could be a giant S. Asia grid, linking up renewable power inputs. A much better bet, I would have thought, than large invasive hydro plants- or, of course, nuclear plants.

With exciting and ambitious new projects like this emerging, its hardly surprising then that the big international power companies like ABB, which was once a major player in the nuclear field, have switched over to renewables as a key part of their development strategy for the future. We in the UK have got to ride this new green energy wave- or be left behind.

Conclusion

To summarise, temporary solutions to the problem of carbon emissions from power stations, such as the switch to gas burning for electricity supply, are just that, temporary. Sequestration, by storage, is also likely to be a temporary option. Conservation and the efficient generation and use of fuel is vital, but we will also need new clean sources to replace fossil fuel. Nuclear is not the way ahead- it's not clean, safe or cheap. Trying to resuscitate it will absorb funds that could be spent on developing more sustainable options- the renewables. They present some fascinating technological challenges, as well as very large commercial opportunities. And, to come back to where I started, they will help us reduce carbon dioxide emissions dramatically.