Mitigation Exam Flashcards
What is climate change mitigation?
Climate change mitigation = practical action to reduce anthropogenic greenhouse gases (GHG) emissions into the atmosphere
- to prevent global temperature increase
- & its consequent impacts
Mitigation and adaptation go hand-in-hand to address the issue of climate change
Why is climate change the biggest challenge ever faced?
Board impacts:
- uncertain in form and extent;
- Gradual and insidious onset rather than directly confrontational;
- Long term threat rather than immediate
Broad in remedies; Effective remedies are beyond the scope of anyone nation; requires international co-operation of unprecedented dimension and complexity
But it requires action NOW
How do we justify and measure mitigation (4)?
“The benefits of a certain level of mitigation must outweigh the costs of that level of mitigation”
Avoided climate impacts = benefits
- Currently measurable market impacts – GDP/consumption (post flood repairs)
- Market impacts not readily measurable – e.g. impact ecosystem change on tourism
- Insurance value against high damages – naturally risk averse to events potential catastrophe defence damage
- Non-market impacts – e.g. damage to landmarks, barrier reef, loss of species
How do you value the future relative to the present?
Utilities across generations is measured by a discount rate – the higher, the less the future utility counts today.
Typically between 3-5%
Ethically = 0 – equal standing.
Marginal elasticity of utility = wealthier people value differently; assume we will be wealthier = > 0
What does the task of global mitigation entail? (4)
- Limit the negative impacts of CC (prevent dangerous impacts)
- Limit rise in global temperature (2degree pre-industrial)
- Stabilize concentrations of GHG in atmosphere (450ppm)
- Reduce GHG into atmosphere (halve by 2050)
How are we doing in terms of likelihood of temperature rise? Pathways?
Parts per million (degrees)
450: 1.5 = more unlikely; 2 = likely; 3 = likely
500: 1.5 = unlikely; 2 = more likely; 3= likely
500 overshoot: 1.5 = unlikely; 2= about as likely; 3 = likely
(In all ppm scenarios likely under 3, but 1.5 unlikely in all. 2 degrees is only likely in the first scenario and maybe 500ppm).
Cumulative budget (staying below GT CO2 left)
1.5 degrees; 66% = 400; 50% = 550; 33% = 850
2 degrees; 66% = 1000 left; 50% =1300; 33% = 1500;
3 degrees: 66% = 2400; 50% = 2800; 33% = 3250
1000 GTC02 is the key figure for staying 66% of staying under 2 degrees – window for 2 degrees rapidly closing as we use up our remaining cumulative budget.
How are we doing on our current carbon budget?
150 already emitted in 2011- 2015 +
100 expected deforestation & land use +
150 (process emissions from cement etc. 2015-2100)
Leaves 600 (if taking 1000) .
Average annual rate of emissions = 35 gt/yr = leaves 17 years.
Assuming we are constant – but we are not, we’re increasing.
How can stabilization be achieved?
Key concept: probability of a certain pathway resulting in temperature rise.
Multiple pathways to same goal; trade-off between emissions peak (delayed action) and rate of reduction thereafter; limiting peak atmospheric concentrations – danger of overshooting.
Cumulative emissions also matter.
What is the current pathway we are on?
Contributions so far = no way near – increased.
Pledges = 2.4 -2.7 – exceed warming limit of Paris agreement.
Current policies = 3.3 – 5.4
What does the emissions division look like globally/historically?
Question of equity – how do we decide and make it fair? Who’s emitting most
- Historically: US (26%); EU (23%) China (11%) and India (4%) = 64% total
- Now: China, US, EU, India, Russia, Japan.
- But impacts not experienced equally – some of the most affected are the lowest emitters
What is climate justice & its underlying principles?
Common but differentiated responsibilities in light of respective capabilities
Developed countries = largest share of historical and current
Developing countries need to adapt too; but need to develop to adapt and that’s highly linked to emissions = ‘right to emit’.
Developing countries emissions per capita are relatively low => will grow to meet their needs = UNFCCC.
Underlying principles for climate justice:
- equality (same right to atmosphere resource);
- historic responsibility (polluter pays)
- capacity to pay.
Equitable/Burden sharing principles/options? (6)
Index Based Approach (historical responsibility)
Common but differentiated convergence (equal emissions & historical)
Contraction/convergence (most popular – equal emissions)
Carbon Budget Approach (equal emissions)
Cost prop. to GDP/capita (capacity to pay)
Income Classification (capacity to pay)
Carbon Budget Approach
Proportion of global carbon budget allocated on basis of population
(equal emissions)
Index Based Approach
Share of mitigation determined by share of historical emissions
(historical responsibility)
Contraction/convergence
Country emissions follow a pathway where they contract to converge on the same emissions per capita by a specified date
(equal emissions)
Common but differentiated convergence
Countries further differentiated on their level of economic development. Countries below per capita threshold can carry on with BaU.
(equal emissions & historical)
Cost prop. to GDP/capita
Targets set based on equal mitigation costs as a percentage of GDP
(capacity to pay)
Income Classification approach
Targets set based on mitigation costs as a percentage of GDP but higher % for wealthier countries
(capacity to pay)
Approach taken by the UNFCCC in terms of burden sharing?
Differentiation by:
Annex I (developed); Non- Annex (developing); Least developed & small island states (lack capability to adapt and likely impacted severely)
Annex I meant to take the lead with specific mitigation targets and timelines & expected to provide funding and resources (tech transfer to developing)
Breakdown of GHG emissions?
65% = CO2; 16% = CH4; 11% = CO2 FOLU (afforestation and land use); 6.2% = N20 2% = HFC; PFC, SF6
Breakdown of where emissions are coming from (Sectors) & Indirect/Direct?
Total: AFOLU = 24%; Industry = 18%; Indirect Industry = 10.6%; Indirect Buildings = 12%; Road = 10.6%
75% = Direct Emissions: arise from the combustion of fuels during activity (exhaust of petrol car)
25% = Indirect Emissions: those associated with the production of electricity/hydrogen
Where do the GHG come from?
Primarily an energy problem!
Majority comes from burning fossil fuel for energy
77% of CO2 comes from electricity & heat, industry and transportation.
Achieving Mitigation Aims as set out by Paris Agreement & technologies?
Currently emitting 628 MTCO2e
2050: 160 MTCO2e
=75% cut
The sectoral overview of emissions means we can’t do everything in one sector – nor leave any behind – has to be cross economy and 3-4% reduction year after year; with wide range of technologies.
Reductions by tech:
38% = Energy Use and fuel efficiency 30% = Renewables 13% = CCS 10% = End use fuel switching 8% = Nuclear
What are the drivers of energy demand & equation?
1) Population growth; 2) GDP growth (total & per capita)
= main drivers of CO2.
CO2 emissions = PopIncomeEnergy Intensity * CO2 Intensity
CO2 emissions = Pop * (GDP/POP) * (ENERGY/GDP) * (CO2/ENERGY)
How can we decouple CO2 Emissions from Growth?
Dealing with the two terms of CO2 emissions:
Energy intensity (demand side) and CO2 intensity (supply side)
1) Energy efficiency (demand side) = energy intensity improvement to the demand side: reducing overall energy demand; behavioural change (tech w/o fossil)
2) CO2 intensity (supply side): Fuel switching (to clean fossil fuel = inc. CCS); renewables (solar & wind particularly), Nuclear
What does the global energy system look like? Primary source to end use?
Different uses for energy making up the energy system.
5 Primary sources:
coal, oil, gas, renewables, nuclear
3 Transformation processes: Electricity (services all) heating fuels (only heat), transport fuels (only transport)
4 Energy Services = Lighting, Electrical Appliances, Heat and Transport.
Converting coal and natural gas into electricity has substantial conversion losses – (it’s the thermal efficiency of coal power stations =1/4 loss; converting chemical energy is not very efficient.
Global demand for primary energy?
From the first car, energy and oil consumption has risen dramatically. Today, 80% of primary energy = fossil fuels.
Electricity Supply Generation?
How to decarbonize?
41% coal; 22% gas; 11% nuclear; 16% hydro; 4% oil; 3% wind; 2% biomass; 1% solar PV
- Need more efficient coal fired power
- Switching from coal to natural gas & biomass (or co-firing)
- CCS + Nuclear + Renewables + energy storage & intermittency
Coal
41% of electricity supply: The most abundant fossil fuel & cheap. 1 trillion tons proven reserve; 150 years at current consumption rates. Demand fell first time in 2015.
= 29% of energy demand (2nd to oil = 31%)
Simplified Efficiency Calculation?
Ratio of in vs. out = Efficiency (n) of planet = electricity produced/energy input
= Look at this calculation
Meeting a 2 degree pathway with coal?
Requires early decommissioning of coal – all need to be ultra-super critical + CCS
Difficult as most plants already paid off and now provide steady revenue stream – need to be forced.
Shale Gas (Fracking) impact?
Shale gas boom resulted in a glut of supply and drove down natural gas prices, difficult for non-gas power generation technologies to compete, largely resulted in displacement of coal (through early retirement of coal-fired power stations) – natural gas could have replaced renewables, but didn’t due to policy.
Role of natural gas-fired generation in future?
Advancement CCGT => boom in natural gas generation with the share in OECD countries of 15%. This saved emissions of ~1 Gt/per annum compared to if this electricity had come from coal.
2 roles (transition fuel):
- displacing emissions intensive coal-fired power stations 2. complementing renewables by providing flexibility.
Danger of capital lock-in: need to be able to be retrofitted with CCS.
Why is CCS challenging/costly?
Capturing from power plant is difficult because we burn fuel in air (78% nitrogen) – separating CO2 from nitrogen is not easy (i.e. it’s expensive) = 82% of costs; 7% transport; 11% storage.
Costs are still very high (far right on marginal abatement cost curve) can do individual processes…
- demonstrate at scale + how operate as a system (integration)
- upfront capital is so high, that this is where we stumble.
Role of Nuclear?
- Nuclear supplied ~13% of electricity + only large scale source of low carbon electricity in many places. Esp. w/o large scale hydro
- Cost of mitigation greatly increased without: 2 degree scenario 10-35% cheaper than with phase-out
ETP (energy technology perspective) projects 16% nuclear in 2050 in their 2 degrees.
= weigh risks of disaster against risks of CC.
Issues: Safety and Controversy, waste (storage sites); high up front capital - gov guarantee price
Non Electricity Supply Technologies?
Hydrogen = potential to play a role across all end-use appliances.
Fuel EV; replace Natural Gas for heating & cooking; low carbon production steel; planes; energy storage.
But hydrogen low carbon production is not easy:
- Need CCS +
To be widespread:
- infrastructure - requires transport distribution networks
- demand-side equipment redesigned (retrofitting/replacing boilers/cookers).
What are the qualities of electricity?
Flow of electrons driven by a potential difference (voltage).
Must be used as it is created (unlike eg. gas). Can only be stored in specifically designed devices, can be use directly off grid. Usually measured in KWh.
Transmitted (long distance, high voltage 400kV) & Distributed (smaller scale, lower voltage 230V – 132kv) - through grid system.
Direct current= always one direction = solar PV
Alternating current (switches rapidly) = national grid = AC + some forms of electricity generation generate in AC directly (usually those involving rotation, eg. conventional thermal) – most electrical appliances.
Requires inverter between – adds cost & loses efficiency
What are the renewable energies and trends/deployment?
Global = 19% global energy consumption.
Hydro (16%); Wind (4) Bio (2) Solar PV (1.2) Geothermal (0.4)
Timing matters - 2030 vs. 2020 - double.
The costs of electrical energy generation from renewables approaching fossil many regions.
Ensuring continued levels of deployment = managing variability of supply.
What is grid parity?
Same cost as grid power per unit of electricity.
Comparing the electricity generation technologies (between all)?
Useful metrics to compare:
Output = capacity factor Reliability of supply = capacity credit LOCE = cost (operating cost) Emissions intensity = emissions intensity Land Use
What is the capacity factor?
Ratio quantifies typical output of generating source over given time period.
Capacity factor = actual energy produced/energy produced if 100% running
UK: Nuclear 1 = 75%; Bio 2=68%; Hydro 3: 41%; Coal 4: 39%; Wind: 34%; CCGT; Solar 12%; Marine 3%
Not 100% all the time due to:
- planned/unplanned maintenance;
- intentional ramping up/down supply to meet demand/respond to economics of generation at price;
- unavailability of fuel (wind/sunlight)
What is the capacity credit?
Reliability = amount of output statistically relied upon at peak demand.
Expressed as: Peak demand - peak residual demand = % of variable renewables installed
CC peak = reduction in capacity conventional plants/capacity variable plants
What is the levelized cost of electricity?
Cost of generation.
- LCOE = NPV cost of a generating asset per unit of electricity generated over its lifetime.
- Quite a few renewables are competitive with fossil: hydro, biomass, geothermal, wind onshore, solar, wind offshore.
What is emissions intensity?
Total quantity of greenhouse gases emitted by tech over entire life / divided by total energy produced over life
Coal = 101; Natural Gas = 469; Solar PV = 46; Geothermal = 45; CSP = 22; Biomass = 18; Nuclear = 16; Onshore = 12; Hydro = 4
Natural gas half of coal
Land Use as a metric?
In 2050 80 reduction scenario UK:
1) Bio 2) Onshore 3) Offshore 4) Hydro 5) Solar
What is intermittency in supply and variability in demand?
Times of peak demand do not match times of peak supply - intermittent and variable over various:
Temporal timescales: longer term outages – daily vs. seasonal - (we’re getting better at weather forecasts but still)
Spatial timescales: Also dependent on grid connectedness or off-grid
What services/technologies do the electricity system require to deal with intermittency?
Methods for balancing electricity supply to meet demand?
Frequency response, daily peak shifting/arbitrage, longer term/seasonal
Demand side management, increased interconnectivity, energy storage, flexible/dispatchable generation
What is the system margin?
The amount by which the total installed capacity of all the generating plants on the system exceeds the anticipated peak demand
