The concept is simple, a household has, say, 10 kwh of electrical storage and by some yet-to-exist technology which gives it the ability to "buy" electricity from a variety of suppliers. It makes use of sustainable energy when it is available and if there is a surplus stores it for use when the sun does not shine (i.e. at night) or when the wind does not blow. It first checks to see if any solar energy is available on a local grid and if none is available it sees what wind farms can offer and finally when the storage is exhausted, falls back on conventionally generated supplies.
As with many simulations, there are a lot of assumptions and arbitrary rules, so the conclusions suggest a direction of travel rather than precise estimates of how such a system might behave. Renewable currently account for roughly 15% of the electricity consumed in the UK, by incorporating storage into a home's energy system, an individual house might increase this to 50 - 80%.
Whilst wind and solar generation are critical technologies in a sustainable energy economy they are both weather dependent sources and require either storage or a backup in the form of gas fuelled power stations to bridge the gap between intermittent supply and regular demand. The pattern of investment that seems to be emerging is that offshore wind farms are incremental to conventional capacity and this raises the question: "Is it possible to displace some fossil/nuclear capacity by increasing the use of energy storage".
When I first started thinking about a simulation to explore this idea I had in mind the lead-acid battery packs used by fork lift trucks, however, since then products like Tesla's PowerWall have become available and these have the advantage of being packaged as consumer products. As electric vehicles become more common, the profile of electrical energy storage will become more familiar. It also raises the possibility of using the family car as part of the household energy supply. For example, most cars do very little, often sitting around car parks at the end of the commute, if during that time, the car is charging itself on wind or solar generated electricity, it might return home with a surplus which can be used to light the home and cook the evening meal (I appreciate there might be some complexities in this scenario).
The current electricity supply model has evolved on two assumptions:
- That supply and demand can only be synchronized by adjusting the output of generators
- There is no limit to consumption
If these constraints are relaxed, alternatives forms development emerge. Storage helps with the first item and the second is a challenge. People do not buy energy, they purchase the benefits it provides. One example of a technology which delivers this is LED lighting. A decade ago our home was lit with incandescent bulbs and it consumed 20 kwh/day, now with LEDs we are down to 4 kwh/day and we can still see to read.
The potential to re-apply investment in energy infrastructure is illustrated by a hypothetical nuclear power station. Say it costs £20 billion and several years to build a 2,000 MW unit. If the average home consumes 4,500 kwh/year, this imaginary project with a load factor of 90% can supply approximately 3.6 million homes. This very simplistic calculation suggests that one power station represents an investment of £5.5k/household. This is similar to the cost of a 10 kwh storage unit.
Sustainable energy sources are unlikely to fully replace conventional ones but there is scope to investigate some alternatives.
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