Thermal energy storage in Scotland

Transcription

1 Thermal energy storage in Scotland UKTES, Imperial College, 8 th June 2016 Dr Jonathan Radcliffe, Senior Research Fellow & Policy Director, Birmingham Energy Institute j.radcliffe@bham.ac.uk;

2 reducing-emissions/ energy-storage-scotland/

3 Growth of renewable electricity generation in UK Indicative 2020 targets from 2009 Sources: UK Energy in Brief (DECC, 2015), UK Renewable Energy Roadmap (DECC, 2009) Sources: UK Energy in Brief (DECC, 2014), UK Renewable Energy Roadmap (DECC, 2009)

4 Renewables generation in Scotland Source: DECC Energy Trends (2016)

5 Future electricity generation in Scotland Source: Scottish Government, Electricity Generation Policy Statement, 2013

6 Generation in GB 12 18/5/16 MW Half-hourly data from Elexon

7 Heat demand in Scotland

8 Heat demand in Scotland Almost a quarter of domestic electricity usage is by households with Economy 7 meters, with storage heaters. Typically less than half of energy supplied to storage heaters is available by evening. Space heating from electricity is often inadequate, though most are not situated in homes with good energy efficiency rating. 13% of households use electricity for heating, 30% of post 1982 flats, A majority of customers with electric heating are in fuel poverty. 27% of households in Scotland in fuel poverty (cf 14% in England) Half of households do not have HW storage. UK surveys show that HW tanks disliked due to space requirements and inflexibility of planning use of HW.

9 Heat demand and wind generation in Scotland Sources: National Grid (gas), DECC Energy Trends (2016)

10 Energy system need for flexibility Main elements of UK energy system scenarios to meet 2050 GHG targets: Decarbonise power sector Increase energy efficiency Electrification of demand Challenges will become more acute in pathways to 2050: Large proportion of intermittent generation by early 2020s Increase in demand for electricity for heating and transport in late 2020s Many scenarios which have guided policy not able to treat power system balancing effectively, nor the dynamic evolution of technology deployment. Timescale Challenge Seconds Renewable generation introduces harmonics and affects power supply quality. Minutes Rapid ramping to respond to changing supply from wind generation. Hours Daily peak for electricity is greater to meet demand for heat. Hours - Variability of wind generation days needs back-up supply or demand response. Months Increased use of electricity for heat leads to strong seasonal demand profile.

11 Providing flexibility There are various means of meeting the same general and specific challenges: Flexible generation Gas power stations are the default. Future options may include nuclear and fossil fuel CCS with greater ability to flex generation cost-effectively. Demand side response smart meters, heat pumps and EVs deployed over the next decade can give consumers a mechanism to shift loads, but needs appropriate functionality and incentives. Interconnection provides additional capacity or load for the UK, but relies on capacity being available elsewhere. Energy storage (inc H2) can capture off-peak or excess generation and deliver at peak times, does not compromise national security of supply, does not require behavioural change from consumers.

12 Electricity flow Scotland to rest of UK G. Anandarajah and W. McDowall, What are the costs of Scotland s Climate and renewable policies? Energy policy, Vol. 50, November 2012, Pp

13 Existing energy storage Coal: 1Mt coal = 3,000 GWh e (about two months output at 2GW) Current gas storage 50,000 GWh Pumped hydro storage: total UK = 28GWh e Hot water cylinder: one tank = 6kWh th ; 14m tanks = 84GWh th

14 Seconds Discharge time at power rating Minutes Hours Electricity Storage Technology options Reserve & response services Transmission & distribution grid support Bulk power management Hydrogen Fuel Cells Pumped hydro storage High Energy Supercapacitors Compressed Air Energy Storage Flow batteries Liquid Air Energy Storage Sodium sulphur batteries Advanced lead-acid batteries Li-ion batteries Advanced lead-acid batteries Nickel-Cadmium batteries Nickel metal hydride batteries Flywheels Thermal Electrochemical Mechanical Electrical Chemical High Power Supercapacitors Superconducting magnetic energy storage 1kW 10kW 100kW 1MW 10MW 100MW 1GW

15 Thermal energy storage (TES) Sensible heat: raising/lowering temperature of a material Phase change: stores latent heat at a constant temperature corresponding to the phase transition temperature of the material. Thermo-chemical: reversible chemical reaction which give up or absorb heat.

16 Thermal energy storage: Applications and technologies Electricity stored thermally for heat, over periods of minutes to months e.g. heat pumps, storing heat in water or novel materials, underground TES Electricity stored thermally for electricity, over period of minutes to hours, to balance the network e.g. pumped heat energy storage Thermal energy stored thermally for heat e.g. capturing industrial waste heat for local space/water heating Thermal energy stored thermally for electricity, over period of hours e.g. waste heat stored for later generation during wind lulls, with cryogenic energy storage

17 Opportunities for TES Supply Heat Electricity Demand Heat Phase-change materials (salts, paraffin); solid/liquid sensible heat storage (water, concrete, subsurface); thermo-chemical reactions Waste/surplus heat fed into DHN Gas/biomass-fired boilers or CHP run at maximum efficiency for heat networks Domestic hot water from boiler for use when required Wrong-time electricity from renewables stored for peak heat demand Liquid air energy storage; Compressed air energy storage; Pumped heat electricity storage Electricity Waste/surplus heat converted to electricity for peak electricity demand Wrong-time electricity from renewables stored thermally for peak electricity demand Thermal power stations run at maximum efficiency

18 Examples Sensible TES with heat network in Turin 10,000m3 hot water buffers Reduces back-up boiler capacity 990MW 680MW Underground TES, Drake Landing Solar Community, Canada 52 homes with DHN and UTES :144 boreholes, 37m deep Provided 97% of heating after 5 years Marstal district heating system, Denmark (SUNSTORE 4) 75,000 m3 water above ground Sunamp heat batteries in Lothian and Falkirk funded by Scottish Govt Local Energy Challenge Fund

19 Smart power? Smart Power, National Infrastructure Commission (2016) The Commission s central finding is that smart power principally built around three innovations, interconnection, storage, and demand flexibility could save consumers up to 8 billion a year by 2030, help the UK meet its 2050 carbon targets, and secure the UK s energy supply for generations. Crucially, storage technology will not need subsidies to be attractive to investors businesses are already queuing up to invest. Regulation, on the other hand, does require attention. When our electricity markets were designed these technologies did not exist.

20 Recommended priority activities 1. Development of TES that can provide more effective domestic heating from: Electricity: improve inadequate storage heaters Heat networks: to reduce the peak capacity required. 2. Retain existing thermal energy storage, in the form of hot water tanks 3. Enable smart control technologies that allow distributed TES to respond to system signals 4. Test seasonal thermal storage, to meet winter heating demand from heat stored in the summer. 5. Support demonstration of near-to-market TES technologies at scale Scale-up to de-risk further investment and to better understand better how the energy system responds to new technologies. 6. Build on capacity and capability in TES in Scotland to take advantage of an emerging market. 7. Assess policy and regulatory frameworks for energy storage, to avoid the creation of unintended barriers to deployment. The business case for commercialisation struggles in the current policy environment and market framework.

21 Conclusions Thermal energy storage could help balance changing patterns of supply and demand in Scotland Technologies exist and are in development to meet the challenges Whole energy system analysis needed to show a future benefit Need combination of technological and policy support to drive innovation Complexities associated when taking whole-systems perspective with multiple objectives Time horizons for support mechanisms are critical Need coordinated and long-term view Short-term fixes could crowd the market for more efficient long-term solutions

22 Thank