L3 Flashcards
What are the key strategies for transformation in the energy sector consistent with Paris?
- Improve energy efficiency
- final energy demand in 2050, +20 to -10% relative to 2010 levels
- not switching fuel but improving tech fro the same output with less energy - Electrify energy end us
- mobility, buildings and industry
would need to consider where the energy is being sourced - Decarbonise the power sector
- carbon intensity fo electricity about 0 or negative in 2050 - Subst. residual ff with low-carbon options
- eg. sustainable bio-based fuels or green hydrogen for transport
Can you speak to the predications in the energy sector from 2030 to 2100?
FF show a clear decline but with variations until the mid-centry
coal has a strong decline, oil declines to a lesser degree, gas decline depends on assumption about capture technology
Renewables are called up robustly
15% of primary energy in 2020 to 50-65% of primary energy by 2050
What is the role of the electricity sector in decarbonisation?
- essential for daily life and clean energy provision
- demand has grown steadily ~3.4%/yr over the last 40 years
- electricity currently the largest source of emissions in the global energy sector?
- electrification of demand sectors is a key mitigation lever
- emissions cuts from electricity production are central to achieving net zero
- there is a potential for net negative emissions if offset residual emissions in other sectors
What are potential mitigation apporaches in the electricity sector?
Approaches with varying effectivness to achieve net zero Co2 emissions = not all mitigation measures are equally effective or desirable
- renewables - wind,s solar etc.
- more efficient coal-fired power generation - supercritical and ultra-supercritical
- switching from coal to natural gas
- phasing out unabated ff entirely
- switching to or co-firing with biomass
- nuclear
- green hydrogen
- carbon capture and storage
Are we on track to achieve this transformation - ff perspective?
- Primary mix of electricity is still made up of a v high share of ff
South Africa per capita electricity from ff is 97% compared with 45% in the UK
Sweden has a v low ff per capita electricity relying mainly on 67% renewables due to a lot of hydro energy
Brazil has 77% renewable - mainly biomass due to abundant forest
- coal still dominates 40% of global power production
we are still building new coal plants and ~10% of them are the least efficient = subcritical plants
coal fired retirement is increasing but not fast enough - prevent more coal power plants without ccs - committed emissions are problematic and there is a need for early retirement of polluting infrastructure
Co2 emissions from coal have plateaued and may have peaked but decline is not fast enough to be in line with the pairs benchmark
Are we on track for this transformation - renewables perspective?
- Renewable energy now makes up 26% of electricity generation - majority hydro (16%)
- solar PV and onshore wind reaching cost parity with conventional power
other technologies are not on track and need more investment to reduce costs eg. bioenergy, hydro and geothermal - there have been government commitments and subsidies from Indian and Chinese government resulting in a high deployment of this tech
- CCS plants remain v expensive but developing countries can take advantage of this technology
Where are we now with CCS and where do we need to be to meet the pairs agreement?
Currently:
30 large scale CCS plants in opp
11 under construction
153 in development
capacity together would be 244 MtCo2/yr capture capacity
Paris Agree:
1000s CCS facilities
Several GtCo2.yr of CCS by 2050
How does electrification of other sectors play a role?
Most 1.5o scenarios include the electrification of ff depdent sectors like transport, heating and industry
renewables will be key in the future energy systems
Speak to supply and demand of renewables
Time of peak supply do not match to time of peak demand
- industry and commercial sector during the day demand is high
supply is variable - seasonal and within a day
supply is intermittent over a range of timeselves - significant variation from average in each trace
this presents a challenge to ensuring consistent electricity supply.
there is a mismatch and requires a flexibility in the system to ensure a constant supply in electricity
Can you give examples of things that are predictable, relatively predictable and hard to predict
Seasonal and daily cycles - predictable
weather patterns - relatively predictable –> have got more predictable over time
brief interruptions - hard to predict thus have to have flexibility in the system to deal with these kind of shocks
What is a capacity factor?
a metric quantifying the typical output of a generating source over a given time period
the ratio of actual electrical energy output over a given period of time to the max possible electrical energy output over the same period
Capacity factor = actual energy produced/ energy produced if system running 100% of the time
Why does electricity sources not generate at full capacity all of the time?
- planned or unplanned maintenance
- intentional ramping up and down of supply to meet demand/response to the economics of generating at the current electricity price
- unavailability of fuel - including wind, sunlight, and water for renewables
- other environmental factors
capacity factors may vary by geographical location and time of year
What is capacity credit?
The conventional thermal capacity that an intermittent generator can replace while still delivering the same reliability of supply to energy users
typically a percentage - capacity credit is the % of the sources rated capacity which it may be statistically relied upon to provide at times of peak demand
What happens to capacity credit when deployment of an intermittent generation source increases?
capacity will tend to decrease
What is another word for capacity credit?
de-rating factor
Can you speak to how capacity credit varies globally?
Dependent on region, type and quantity of renewables deployed, times of high demand, generation mix, and electricity system flexibility
What is flexibility in supply energy?
Using a mixture of sources to match demand. Have sufficient knowledge and resources to forecast future demand
dispatchable technologies give you flexibility in the system
What are the two broad categories of flexibility services?
Short term system balancing
reliability through capacity provision
What is short term system balancing?
= balancing of supply and demand to ensure system stability to fluctuation over seconds or hours
means to level out frequency deviation in the power grid - in GB these are primarily contracted through the electricity grid operator eg. national grid ESO
Can you give some examples of short term balancing - seconds, minutes and hours?
Seconds
= frequency respond
- a rapid response service that keeps alternating frequency of the grid within regulator limits
-increasingly challenging with intermittent generation
-enhanced response requires 1 sec, primary is 10 and secondary is 30 sec
Minutes
=voltage support/ reactive power
- a service to keep voltage within regulator limits
- responds to local needs, requiring distributed solutions
typically within 2 mins
Hours
= Reserve capacity
- a mechanism to ensure sufficient power is available to accommodate fluctuations in electrical supply and demand on timesclaes of 2mins to a few hours
- national grid - fast reserve up to 15 mins and short term operating reser - up to 2 hours
reserve capacity essentially works as an insurance if renewable tech fails
What is a capacity market?
represents competition to provide reliable capacity on the grid through periodic auctions
requires guarantee that a service can provide power during periods of peak demand
was illegal under EU competition law in 2018 - US is relaunching
used in France, Poland, Australia and parts of the US
What is reliability through capacity provision?
long term planning to ensure generating capacity is available required to ensure that a system can reliably meet peak demand
If there is insufficient capacity in the electrical grid what happens
electricity is traded in the trading markets
prices are high and the surplus is v low
indicative of poor reserve capacity and a lack of investment in capacity
or
try and incentivise a reduction in demand - smart grids and devices
incentivise a shift in behaviour
How do you balance supply and demand off-grid?
Flexibility mechanims must serve to balance supply and demand at all times - typically to within a reasonable threshold
communities are gaining access to electricity for the first time - the challenge is predicting demand and appro. system sizing
How can flexibility be managed ?
Energy storage
complementarity and increased interconnectivity
eg. no wind in one part, take it from another place eg. germany into the UK
demand side management
eg. smart grid or smart devices
dispatchable generation
eg. biomass or nuclear - adds flexibility
What is an example of an electrochemical electrical energy storage technology and what are some of its characteristics?
batteries like lithium-ion, lead-acid, high-temperature sodium-sulphur
Characteristics
- able to operate at a range of scales, able to provide rapid response, and a balance of high power and energy
- high energy density of lithium-ion allows use in EVs
-electrolysis for hydrogen could be significant for seasonal storage and other energy vectors
What is the pattern of costs for lithium batteries and what are the consequences of this?
costs are falling - could dominate more services than had previously been anticipated
- most cost effective technology for a range of storage options
- modulatiry of lithium-ion batteries presents an opportunity for repeated manufacture and learning-by-doing - potentially driving costs down quickly
What is an example of an electromagnetic energy storage technology and what are the characteristics?
eg. supercapacitors, superconducting magentic energy storage - SMES
Characteristics:
- suitable for delivering high power for seconds to minutes at short notice
- high power density - v fast acceleration and disacceleration of electricity
Can you give an example of a mechanical electrical storage technology?
eg. pumped hydropower storage and compressed air energy storage
Characteristics
- suitable for storing relatively large quantities of energy (MWh) over minutes to hours
- rely on robust components with long lifetimes ~10 yrs
- large scale projects with long build times
eg. flywhells
characteristics
- suitable for delivering high power for seconds to minutes at short notice
What are some examples of thermal electrical energy storage technologies and what are the characteristics?
eg. liquid air energy storage, pumped heat energy storage
Characteristics
- less geographical requirements than compressed air energy storage
- efficiency improved with access to industrial waste hot/cold
- more costly than other bulk solutions
what is the relationship between storage costs with cumulative capacity?
storage costs are falling with increasing cumulative capacity
there is a storage requirement with renewable technology especially if there is a flexibility requirement
What is the impact of increasing interconnectivity?
Macdonald et al 2016 - show that 80% (comapred to 1990) of US electricity sectors carbon dioxide emissions could be reduced due to extending connectivity without storage
development of strategies based on understanding wind patterns could be instrumental across Europe - collaboration could enable a high share of wind power and minimise the negative impacts of output variability
What is demand side management?
- Measure to incentivise reduced electricity during peak hours
- could include moving energy use to off-peak times such as during the evening and weekends
- apply to both domestic and industrial consumers
- operates over a range of timescales and requires different degrees of infrastructure and co-operation
eg. the rollout of smart meters providing 1/2hr readings in the UK enables variable electricity tariffs to incentives shifting times of demand
e.g. electrification of transport and heat pumps could provide important sources of flexible demand
Can all of the flexibility mechanisms be used everywhere?
depending on geographical and temporal scale and context, different sets of these mechanisms will be available and cost-effective.
