We Claim:
1. A method of using a thermal energy store capable of accepting, storing and releasing thermal energy at a range of more than one temperature to/from at least one thermal energy source and/or sink, said thermal energy store comprising:
a configuration of three or more thermal energy storage banks, (102a - 102h) each of said thermal energy storage banks having an operating temperature range;
at least one or more of the thermal energy storage banks contains thermal energy storage material comprising a single material or a mixture of materials;
wherein said thermal energy storage material in at least one bank contains at least some of one or more types of thermal energy storage material that undergoes at least one energy absorbing and/or releasing phase transition at one or more temperatures or one or more sub-ranges of temperatures within the operating temperature ranges of each bank;
wherein each phase transition is associated with a change in physical and/or chemical properties of said thermal energy storage material; and
two or more independently controlled thermal energy transfer connections, wherein each connection comprises one or more devices for transferring heat from a lower temperature body to a higher temperature body, each connection linking two or more banks;
wherein one or more multi-bank phase change material thermal stores includes a control system that regulates the amount of and source of electricity drawn by the system or thermal energy store electrical elements of the system due to a pump and/or a heat pump and/or a thermoelectric device which draws and use electricity based on one or more of the following criteria:
• Stability of the electricity grid;

• Availability of electricity;
• Cost of electricity;
• Carbon intensity of electricity;
• Signals from an electricity grid operator;
• The criticality of the operation of elements of the system.
wherein the source of electricity is a local energy source that co-generates combined heat and electrical power, also known as a local CHP Generator; and
wherein there is controlling electronics and power electronics required for the chosen local electrical generation source, which regulates the amount of and source of electricity drawn.
2. A method of using thermal energy store as claimed in claim 1, wherein the local energy source that co-generates combined heat and electrical power is the electricity grid, fuel cells, diesel generator, hybrid photovoltaic - thermal collectors where PV is overlaid on a conventional flat plate solar thermal collector or solar thermal electrical generators.
3. A method of using a thermal energy store as claimed in any preceding claim, wherein the thermal energy store is integrated into a Smart Grid and acts as one or more virtual dispatchable loads on the electricity grid to effect demand reduction.
4. A method of using a thermal energy store as claimed in any preceding claim, wherein the thermal energy store electrical elements can be independently controlled, changing electricity source for one or more electrical element or turning off one or more electrical element completely wherein decisions are made regarding the action to take for each electrical element based on the following criteria:
• Electrical elements dedicated to heat pumping are prioritised to be switched off first; and/or

• Electrical elements dedicated to transferring heat from external heat sources, for example but not limited to solar panels and waste water heat recovery systems, are only switched off for limited periods or are switched off for longer periods if no heat needs to be captured;
• Electrical elements delivering local services, for example but not limited to space heating and cooling, are only switched off for limited periods in order to maintain a predetermined level of performance of the local services; and/or
• Electrical elements for time critical services, for example but not limited to hot water, will be kept on.

5. A method of using a thermal energy store as claimed in any preceding claim, wherein the thermal energy store is combined with at least one rechargeable battery, the battery being charged by one or more electricity source selected from: photovoltaics, diesel generators, mains electricity.
6. A method of using a thermal energy store as claimed in claim 5, wherein the at least one rechargeable battery is large enough to supply the electricity required to operate the thermal energy store and associated building or section of building.
7. A method of using a thermal energy store as claimed in any preceding claim, wherein heat pumps in the thermal energy store are powered by direct current.
8. A method of using a thermal energy store as claimed in any preceding claim, wherein the thermal energy store is equipped with an inverter to generate alternating current, which may be a grid-tie inverter.
9. A method of using a thermal energy store as claimed in claim 8, wherein the thermal energy store with inverter includes a grid-disconnect switch.
10. A method of using a thermal energy store as claimed in claims 7 and 8, wherein the grid support services delivered are monitored and reported to any combination of the thermal energy store owner, thermal energy store user, the grid operator and/or the electricity supply company.

11. A method of using a thermal energy store as claimed in claims 7 to 10, wherein the control electronics for local electricity generation are integrated into the thermal energy store.
12. A method of using a thermal energy store as claimed in the above claims apart from 5 to 6, wherein the thermal energy store does not include an electrical battery but is equipped with the circuitry to control local electrical power generation and a grid-tie inverter to provide electricity directly to the grid.
13. A method of using a thermal energy store as claimed in any preceding claim, wherein the thermal energy store accepts both electricity and thermal energy from a local combined heat and electrical power source, including but not limited to: one or more fuel cells, diesel generators, hybrid photovoltaic and thermal collectors, and solar thermal electrical generators.
14. A method of using a thermal energy store as claimed in claim 13, wherein local combined heat and electrical power generator's heat and electricity output is modulated based on at least one of the following:

• Local demand for heat;
• Local demand for electricity;
• Storage level of the thermal energy store;
• Electricity demands of the thermal energy store;
• The level of charge of electrical batteries that may be contained in the system.