Leave fossil gas in the ground
Carbon budget logic says that Europe will soon have to cut its use of all fossil fuels sharply, including natural gas. Photo: Astrid-Westvang/flickr.com/ CC BY-NC-ND
Gas is better than coal, but not good enough. Much of it has to be left in the ground, so its use has to be cut fast. This is actually happening in Europe. Gas use fell by 13 per cent between 2010 and 2013.
Natural gas is an important source of energy in Europe. Twenty-three per cent of primary energy supply came from gas in 2012. It is important in many other countries as well.
Of the 5000 TWh of gas used in the EU, about 40 per cent is used for heating, 25-30 per cent for power, and most of the remainder in industry.
A few years ago many believed gas would soon be depleted, but this is not the case.
Proven reserves are estimated at 185.7 trillion m3. New reserves are added each year. The confirmed reserves have doubled since 1987, despite burning some three trillion m3 every year. Even if no more gas is discovered, the present reserves, if combusted, would emit 377 billion tons of CO2 directly, a bit more indirectly.
Much of the gas must be left in the ground.
This follows from the IPCC’s carbon budgets. The remaining CO2 budget, if we accept a 66 per cent probability of staying within two degrees of global warming from 2015 onwards, is 1200 Gtons of CO2.
Two degrees is not safe, and 66 per cent is not sure. But even with such a generous budget there is no way that we can shoehorn in another 400 Gtons of CO2, an extra third, from gas reserves.
The remaining budget in say 10 years will be much diminished. Even if the world stops building coal power plants right now, and many old coal power plants are retired, most newer fossil power plants will be around for several years, as will most of the petroleum-burning cars, lorries, ships and aeroplanes.
The rug is being pulled from under our feet, so some gas infrastructure will have to be retired or downgraded well before it has reached the end of its technical or economic life.
If a “natural gas budget” could be defined, Europe could hardly claim priority for a large share of it, over China, for example. China is being suffocated by coal combustion and has to act on every front simultaneously to improve its air quality and its economy: cleaner coal, more renewables, more nuclear, more gas, more efficiency. China doubled its gas consumption during the same period, but it is still only at half the level of the EU – for a much larger population. China will probably double its gas power between 2013 and 2020, while continuing to develop renewables at breakneck speed.
Europe has much more of a choice than China. The EU uses about 15 per cent of global gas. This can change. It actually reduced its gas consumption by 13 per cent between 2010 and 2013. Most or all of this reduction took place in the power sector. In 2012 alone, gas for power dropped by 17 per cent.
Some of that gas was replaced by cheaper coal. But renewable electricity also increased by 186 TWh in the period 2010-2013. Electricity production fell by 112 TWh.
Almost 10 per cent of EU electricity has become either renewable or obsolete, in just three years.
This unforeseen development hurt gas power first, and (for other reasons) nuclear. It hurts coal power as well, so coal use fell during 2013.
There is now also political momentum for cutting gas consumption in the EU for reasons of security of supply.
Carbon budget logic says that Europe will soon have to cut its use of all fossil fuels sharply, including natural gas.
This is not universally recognized, however, even within the NGO community. The Greenpeace 2012 Energy (R)Evolution scenario for OECD Europe, roughly equivalent to the European Union, prescribes an 11-per-cent increase in natural gas from 2009 to 2020.
BUND, a leading German NGO, also foresees a substantial use of natural gas in Germany through 2040, but not 2050.
The German Solar Energy Support Club has more recently expressed the view that gas power is an acceptable transitory solution.
The reasons for such views are not hard to see.
With coal, lignite and nuclear phased out fast (in Germany), gas seemed much less harmful and also a good way of balancing the increasing share of renewables.
It is indeed much less harmful. A natural gas power plant does not emit particles or SO2 and much less NOx than a coal power plant. The CO2 emissions are also much lower. A coal power plant emits about 1000 grams of CO2 per kWh. The worst lignite power plants in Germany, for example Vattenfall’s Jänschwalde, emit more than 1200 grams. A new gas power plant emits less than 340 grams, a bit more over the full life cycle.
Even 340 grams is much more than emissions from wind, solar, biomass and, above all, better efficiency.
Much gas is used for heating, where it has no climate advantages. The alternative to gas for heating is nowadays seldom coal or oil. It is heat pumps, district heating, and electric heating. The electricity can be, and often is, renewable. Energy for district heating can also be supplied from renewables or waste heat. Another alternative is improved efficiency, such as better windows. It takes time to change heating system, but efficiency measures can cut gas use in the meantime.
Gas for power is easier. Renewables and efficiency measures can reduce the need for fossil and nuclear power very fast. They do, in fact.
Gas has some role to play in balancing the increasing wind and solar power, but it should not be overrated.
Balance can be achieved by several other means, such as hydro, biopower, import/export, geothermal power, concentrated solar power with heat storage, compressed air, flywheels and batteries. Hydro is now used for balancing in Sweden, for example, but nowhere near its limits.
In shorter timescales wind power and photovoltaic technologies can provide some grid support. The electronics between the windmill and the grid can supply “synthetic inertia”, so as to maintain voltage and frequency for several seconds and also give a very rapid response to disruptions in the grid.
The best and cheapest balance comes from demand-side management. This has not been much explored so far, because it has not been needed. But it has huge potential, as many users, big and small, can shift their use of heating, cooling, pressure and some motive power for minutes or hours without detriment, if the incentive is there and if the technology is simple and automatic.
If some fossil power plants are shut down, the drive for demand-side management will be correspondingly stronger.
It would be simpler if we had a high steady emission price for CO2, so coal would have to go first and gas after, but things do not happen in an orderly manner. There is no reason to panic over the demise of a few gas power plants along with many coal and nuclear power plants.