Demand-driven energy supply belongs to the past. Electrons, molecules and heat determine our direction within a future-proof infrastructure.
Why electrons, molecules and heat will have to cooperate
Energy storage and distribution are inextricably linked in an era of renewable energy. The former situation was one of demand-driven energy supply, which is still the order of the day in the Netherlands.
Of course demand varies, depending both on the time of day and the time of the year. Depending on the demand, the energy supply is raised or limited. In the future this will change and the olden days will be gone forever.
Thermohydraulic energy storage systems
Ecovats are thermohydraulic energy storage systems. Gigantic subterranean thermos flasks with accompanying heat collectors and heat generators, complete with hydraulic transport pipes and control software.
In times of wind and solar energy surpluses the water is heated, to be used for heating your house during cold periods. The water stays hot for at least six months and can be used for districts consisting of 500 houses and more.
The importance of a storage balance for the long and short term
In 2012, for a presentation called ‘Future Energy Scenario from the point of view of an Industrial player’ Siemens calculated the ratio between fast storage (= 200 times a year) and slow storage (seasonal storage = 2 to 2.5 times charging and discharging a year) for a 100% sustainable system.
To achieve this, a balance should be reached between these preconditions:
- the Physical calculations
- the Technical practicability
- the Economic feasibility
To arrive at this, 3 axes should be taken into consideration:
- x-axis: Infrastructure expansion. For transport of the three available energy sources Electrons – Molecules – Heat, based on the existing grids, the required peaking power plants, the storage volume (long and short) and smart control.
- y-axis: Total of installed sustainable production capacity.
- z- axis: The amount of unused renewable energy based on the installed capacity (curtailment).
100% sustainable energy system
An optimal storage configuration reduces backup system costs and carbon emissions. With an average electrical load of 13 GW in the Netherlands, the power generation with wind and sun should be overdimensioned with 264% and 462% respectively.
This comes down to a total of installed 35 GW wind and 60 GW sun PV capacity, eventually. The storage capacity required for this will be 33 TWh per year. For seasonal storage 2 cycles per year x 5.5 TWh = 11 TWh, and for fast storage 200 cycles per year x 110 GWh = 22 TWh.
Avoided system costs thanks to Ecovat
To be able to make an integral comparison, Ecovat was eager to know the avoided investments on a systemic level when using the Ecovat system. These avoided investments namely are currently not (yet) included as revenue in the business case.
Various reports have answered part of this question over the past years, but none of them have provided a complete answer. That is why Ecovat has asked Berenschot to quantify the system consequences.
Annual reduction between €97,000 and €167,000 a year
The impact of 66 PJ supplied heat via Ecovats for heating households connected to the energy system is between €380 million and €650 million each year.
This amounts to an annual reduction of between €97,000 and €167,000 per Ecovat project of 17 TJ.
The reduction will increase as electrification grows, which causes the impact on the electricity grid to become larger. In the report you can find the estimated annual costs as well as the reduction translated into terms of capacity.