IPCC on Mitigation: Which technologies help reduce GHG emissions the most?

Intergovernmental Panel on climate Change Working Group 3 (Mitigation) has produced their update from 2007. This post looks at electricity technologies.

Summary, also comments
• Improving efficiency much more rapidly in all sectors (energy production, distribution, and use) is crucial.
• Carbon capture and storage (CCS) is the single biggest addition to business as usual, if our goal is to keep atmospheric levels of CO2-equivalent below 450 ppm, or even 550. Plans for research and development, and deployment, should proceed rapidly and aggressively. (This will be aided by adding a cost to greenhouse gas emissions to cover their cost to society.)
• Bioenergy is the next most important technology. The “limited bioenergy” scenario increases bioenergy use to 5.5 times 2008 levels by 2050, and it will be very costly if we restrict bioenergy to that level. There are a number of concerns about how sustainable this path will be, and with larger increases in temperatures, the quantity of biomass available for electricity and fuels.
• If we don’t get our act together a few years ago, we will be using bioenergy and carbon capture and storage together. Bioenergy will take carbon dioxide out of the atmosphere and CCS will put it into permanent storage. This will cost several hundred dollars/ton CO2, and is relatively cheap compared to the alternative (climate change), although much more expensive than getting our act together.
• To the extent that we add nuclear, wind, and solar as rapidly as makes sense, we reduce dependence on bioenergy.
• Given the relative importance of carbon capture and storage, it may make sense for nations (e.g., Germany) and states (e.g., California) that want to jump start technologies to focus more on CCS than on renewables.
• Do all solutions, now.

Which solutions for electricity are important?
IPCC provides an answer by calculating the cost of failing to use the solution.

Efficiency remains the single largest technology solution, along with shifting to best available technologies: more efficient power plants, cars, buildings, air conditioners, and light bulbs. Since so many buildings are being constructed, and power plants built, with a lifetime of decades, early implementation of efficiency makes the task possible. The cost of failing to add efficiency sufficiently rapidly isn’t calculated in the Summary for Policymakers, but assume it’s more than we want to pay.

Nuclear and Solar + Wind
Can we do without renewables or nuclear power? Looking at only the attempt to reduce greenhouse gas emissions from electricity, IPCC found that opting out of nuclear power would increase costs by 7% in the 450 parts per million CO2-equivalent goal, and limiting wind and solar would increase costs by 6%. To stay below 550 ppm CO2-eq, costs would go up 13% (of a much smaller cost) without nuclear, and 8% without solar and wind. Crossing either off the list looks pretty unattractive.

Go to Working Group 3 for the full report, and the technical summary. IPCC also has an older report, Special Report on Renewable Energy Sources and Climate Change Mitigation.

Caveats re nuclear:

Nuclear energy is a mature low-GHG emission source of baseload power, but its share of global electricity generation has been declining (since 1993). Nuclear energy could make an increasing contribution to low-carbon energy supply, but a variety of barriers and risks exist (robust evidence, high agreement). Those include: operational risks, and the associated concerns, uranium mining risks, financial and regulatory risks, unresolved waste management issues, nuclear weapon proliferation concerns, and adverse public opinion (robust evidence, high agreement). New fuel cycles and reactor technologies addressing some of these issues are being investigated and progress in research and development has been made concerning safety and waste disposal.

I’m not sure what risks are associated with uranium mining.

Caveats re renewable energy (RE), excluding bioenergy:

Regarding electricity generation alone, RE accounted for just over half of the new electricity generating capacity added globally in 2012, led by growth in wind, hydro and solar power. However, many RE technologies still need direct and/or indirect support, if their market shares are to be significantly increased; RE technology policies have been successful in driving recent growth of RE. Challenges for integrating RE into energy systems and the associated costs vary by RE technology, regional circumstances, and the characteristics of the existing background energy system (medium evidence, medium agreement).

Note: the capacity factor for intermittents like wind and solar (and sometimes hydro), the percentage of electricity actually produced compared to what would be produced if the source ran at maximum capacity 24/7, is dramatically less than for nuclear and other sources of electricity. Added capacity (gigawatts brought online) does not communicate how much electricity, GWh, was added. The increase in coal in 2012 was 2.9% (see coal facts 2013). Since coal was 45% of 2011 electricity, the increase in coal was far greater than the increase in wind and solar combined.

The use of bioenergy increases dramatically in all scenarios. If we limit bioenenergy to 5.5 x 2008 levels, costs rise 64% (18% of a smaller number for 550 ppm scenario). Bioenergy, using plants for fuels and power (electricity) dominates high renewables scenarios.

Caveats re bioenergy:

Bioenergy can play a critical role for mitigation, but there are issues to consider, such as the sustainability of practices and the efficiency of bioenergy systems (robust evidence, medium agreement). Barriers to large scale deployment of bioenergy include concerns about GHG emissions from land, food security, water resources, biodiversity conservation and livelihoods. The scientific debate about the overall climate impact related to landuse competition effects of specific bioenergy pathways remains unresolved (robust evidence, high agreement). Bioenergy technologies are diverse and span a wide range of options and technology pathways.

There are many concerns about the amount of bioenergy—biopower and biofuels. With so many demands on land facing an increasing population wishing to supply food, fiber, green chemicals, etc in a world with a rapidly changing climate, sustainability is not foreordained. The Special Report on Renewable Energy Sources and Climate Change Mitigation estimates the net effect on yields to be small worldwide at 2°C, although regional changes are possible. By mid-century, temperature increase over pre-industrial could be more than 2°C, and yields are more uncertain.

Note: fusion energy is not mentioned in this short summary, but such strong dependence on bioenergy gives an idea why there is so much research on somewhat speculative sources of energy.

Carbon Capture and Storage
Carbon capture and storage (CCS) provides even more of the solution—costs go up 138% if we do without carbon capture and storage for the 450 ppm scenario (39% of a smaller number for 550 ppm scenario). Part of the attraction of CCS is that it can help deal with all the electricity currently made using fossil fuels. A number of countries are heavily invested in fossil fuel electricity, and a smaller number of countries, from China to Germany, are adding coal plants at a rapid rate, and will likely be reluctant to let expensive capital investments go unused. Additionally, as International Energy Agency (IEA) points out, almost half of carbon capture and storage is aimed at decarbonizing industry: steel, aluminum, oil refineries, cement, and paper mills use fossil fuel energy directly. Nuclear is often not practical in such situations, and wind and solar rarely are.

BECSS—Bioenergy and CCS
One of the cheaper ways to take carbon out of the atmosphere is to combine bioenergy and carbon capture and storage. Using plant matter to make electricity is nearly carbon neutral, as plants take carbon dioxide out of the atmosphere to grow, and release it back when they are burned for electricity or fuel. However, CCS can store that CO2 permanently. Cheaper is relative to the costs of climate change, as the cost is expected to be several hundred dollars/ton. This method is much more expensive than other methods of addressing climate change that are currently underutilized.

The International Energy Association booklet, Combining Bioenergy with CCS, discusses the challenges of ascertaining whether the biomass was grown sustainably.

Note: IEA gives some sense of how rapidly CCS should come online:

Goal 1: By 2020, the capture of CO2 is successfully demonstrated in at least 30 projects across many sectors, including coal- and gas-fired power generation, gas processing, bioethanol, hydrogen production for chemicals and refining, and DRI. This implies that all of the projects that are currently at an advanced stage of planning are realised and several additional projects are rapidly advanced, leading to over 50 MtCO2 safely and effectively stored per year.

Goal 2: By 2030, CCS is routinely used to reduce emissions in power generation and industry, having been successfully demonstrated in industrial applications including cement manufacture, iron and steel blast furnaces, pulp and paper production, second-generation biofuels and heaters and crackers at refining and chemical sites. This level of activity will lead to the storage of over 2 000 MtCO2/yr.

Goal 3: By 2050, CCS is routinely used to reduce emissions from all applicable processes in power generation and industrial applications at sites around the world, with over 7 000 MtCO2 annually stored in the process.

How much more low-GHG electricity is needed?
IPCC says 3 – 4 times today’s level by 2050. About 33% of today’s electricity is low-GHG, so by mid-century, more electricity than we make today will need to come from fossil fuel and bioenergy with CCS, nuclear, hydro, wind, solar, and other renewables.

For some of the challenges to rapidly increasing reliance on any energy source, see David McKay’s Sustainable Energy—Without the Hot Air.

2 Responses to “IPCC on Mitigation: Which technologies help reduce GHG emissions the most?”

  1. bonnie fraser says:

    So, Karen, I thought that those who knew the most about nuclear power feared it the least and that it has been strongly advocated by IPCC. Now I read in your summary that You say that nuclear power has risks and barriers, with robust evidence and high agreement. But I do not know which of the potential problems is a risk and which a barrier. I understand that there is significant public opposition. Is that the major barrier? Are disposal of wastes, operational risks, potential for nuclear weapons also a barrier in the mind of IPCC scientists? If so, I need to stop saying those who know the most are the least frightened.

  2. Karen Street says:

    Bonnie, short answer: your statement is OK: those who know the most about nuclear power are the least frightened. (The opposite appears to be true re climate change.)

    More details—
    The difference between a risk and a barrier in this context is that a risk is based on uncertain information: barriers exist despite the information. There is deep public opposition to adding a cost to GHG; this is a barrier rather than a risk. Some in the public find any nuclear power plant accident unacceptable, while accepting enormous harm from the use of fossil fuels; this is a barrier.

    Unresolved waste management issues are a barrier, an obstacle to the expansion of nuclear power because some governments, such as in California, forbid new nuclear reactors until a permanent repository is established, but there is little uncertainty about whether any will open (yes, they will) and whether they will operate safely (yes). Nations which reprocess have all delayed site selection. Nations which don’t reprocess are in various stages; Sweden is furthest along in the process; full construction begins at a site near Forsmark in 2015 and the repository is expected to open in 2020.

    Deep geological disposal, a la the Swedish plan and Yucca Mountain, is considered a safe and effective means of isolating nuclear waste long-term; scientific and technological consensus on this is as strong as the consensus on climate change, on the dangers of using the atmosphere as a sewer for fossil fuel waste. Political obstacles to nuclear waste storage presumably will be easier to reverse, as politicians become more concerned about climate change, so it is reasonable to presume that this is a temporary barrier.

    • Operational risks include accidents such as in Fukushima. It is reasonable to compare the environmental and health effects of the oldest Generation II designs with coal plants from the same era. Germany, in closing down older nuclear power plants, did not consider opportunity costs, the relative benefits of closing older coal plants first. In the US, coal plants kill more than 10,000 Americans yearly, and almost 1,000 coal miners; impacts on the environment and agriculture are also severe.

    Accidents will happen, but we don’t know how often, or how serious they will be (although seriousness in terms of both danger to the public and cost appear much, much less with the current Gen III+ plants being built). Fukushima is expected to eventually kill one worker from excess radioactivity (of the hundreds with excess exposure, we would expect one to die) and no members of the public. It was and is scary, exceedingly expensive, and there will be excess deaths as people live in anxiety and delay a return to normal lives (and from increased reliance on fossil fuels).

    • Financial risks exist because nuclear power does not have a clear track record of producing generation III+ plants, such as are being built by Westinghouse in China, and at Vogtle and Summer in the U.S., and by Areva at Olkiluoto, in Finland. The Finnish reactor is behind schedule and over budget. The Vogtle construction is being watched closely in California and elsewhere to see whether it follows the same path or comes in more or less on time and within budget (it is a first build and it might be a tad bit to ask that there be no problems); the two new Vogtle reactors are expected to come online in 2016 and 2017. Also included in this category is uncertainty about the price of natural gas in the US; current low prices has led to the delay of nuclear construction in some areas of the US and the closing of small plants.

    From my reading, economists seem more unsure of the Westinghouse AP1000 cost and schedule than those in industry, even those who tend to caution. This is because much more of the AP1000 is built in-factory, compared to the current Gen II, and because one AP1000 is due to come online in China mid-year (there are technology differences between the Areva reactor in Finland and the Westinghouse model). Because so much of the reactor is built in the factory, prices will come down as quantities increase.

    Another financial risk, only in the US, is due to the temporary low price for natural gas; several utilities in the US delayed nuclear builds, and two small nuclear plants were closed due to their inability to compete against natural gas. Eventually, a cost will be added to GHG emissions, but by that time, some utilities will have invested in natural gas over nuclear.

    Also, mistakes are expensive. San Onofre’s owner will pay dearly for mistakes in steam generator tubes, no matter whether or not they are found most responsible for the mistake. To compare, today’s solar panels appear to be degrading more rapidly than predicted; this is costly, but the risk is spread over more than one utility.

    Regulation improves plant safety. However, both Nuclear Regulatory System and San Onofre’s owner were faulted in the decision to close SONGS. I heard this several times, but don’t know the details. In Japan, the regulators are having trouble finding ways to restart Japan’s nuclear power. Again I don’t know the details.

    • Nuclear proliferation concerns will keep nuclear power out of many areas where there is inadequate security, or an unwillingness to work with International Atomic Energy Agency (such as Iran communicated; now Iran and others are working to find an arrangement that allows the rest of us to be pretty sure they are not working on weapons, and allows both sides to save face). A dysfunctional government may not protect the nuclear fuel, which could, with great technical difficulty, be made into a weapon in countries which reprocess—the odds are tiny that this could happen, but they are not zero with current designs. At least one Generation IV design addresses the problem of inadequate governance: a small nuclear reactor could be delivered anywhere, and collected at the end of its life, with no need for a trained workforce, security, fueling, and so on. Gen IV designs eliminate the small possibility that fuel or waste can be weaponized. The US is not allowed to sell technology in either of these cases, and US academics are working on technologies that will look attractive to manufacturers everywhere, so other countries (Russia) also do not sell. Overall, improvements in reactor technology will overcome risks of proliferation and safety.

    However, it appears that IPCC economists spoke beyond their level of expertise in placing “high confidence” in their judgement of a connection between nuclear energy and nuclear nonproliferation and security. There are institutional measures to manage and reduce these risks; how does civilian nuclear energy affect these? Non-proliferation experts do not put civilian nuclear power high on the list of proliferation concerns. There is a barrier—most of us do not want to sell nuclear power to countries where security is a concern. This does not mean there is a high risk.

    • I have not been able to figure out what IPCC intends in referring to risks with uranium mining. The two guesses that come to mind are risks of accidents, which kill miners or/and damage the environment; so far as I understand, this is less for uranium than gold (gold mining accidents historically have done great environmental damage) and coal (if for no other reason than coal requires more than 100,000 x as much fuel per unit electricity).

    • IPCC calls nuclear a mature technology. It is true that nuclear has been a more or less cost effective means of supplying electricity for decades, and Gen III+, currently being built, is expected to follow suit. (Solar is not yet there.) It is also true that research and development is being done on wholly new designs which are much improved over today’s—old landlines were also a mature technology.