The Cactii Community trades energy amongst members
The core concept is for users to trade energy between those with a surplus and those with a need. These could be neighbours, small businesses or even residents of apartments who are unable to install and benefit from their own renewable energy generation. Any shortfall is made up from the grid with surplus power purchased at default pricing governed by IPART recommended pricing.
The existing poles and wires are used to transport the energy. This carries a cost and is charged at the standard applicable rate for the area by the communities selected Retail Provider and billed as part of their normal billing cycle.
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A typical use scenario would be;
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Power from the Grid is relatively cheap in the morning (within the current billing paradigm) but power from the east facing user is pegged as cheaper by the user.Other members of the community, including the user with West facing panels have had their systems configured (either by themselves or via standard rules) to purchase power from other members first.This power will be cheaper than can be purchased off the grid and they draw down on the other members’ power first. Only when that is fully consumed will they draw down on power from the Grid.
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During midday there would typically be a surplus of power represented by the price. The member with batteries will charge the batteries.It is possible the member will also charge batteries overnight with cheaper off grid power (also providing a more even use of the electricity grid). During the afternoon this member might wish to sell a certain amount of power surplus to requirements. It would be placed on the market within the community within some price range.The automated rules put in place by the community will have them purchasing this power first before drawing down the more constrained highly priced scarce power of the grid.
Referring to the diagram the three main “players” are:
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A simple member of a community with solar generation capacity – they could for example be east facing i.e. they will only generate in the morning/ early afternoon – this user can also just be an ordinary user with no microgeneration i.e. only takes energy;
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A member with, for example, west facing solar generation and batteries. They can generate energy in the afternoon and store energy. This can be released overnight if wished.
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The existing Grid which is used to supplement energy for the community.
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Community members are specifically grouped to try and balance power generation and demand, but also to try and fit with the local poles and wires providers, and energy network boundaries. Where possible these communities will also offer surplus power to other communities from their pool of unused energy. This will be very dependent on the ability to transfer that power.
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Further advantages of setting up communities are:
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Note that at some stage it is anticipated that legislation on the use of the Grid will change. Only those communities effected by local changes will need to be revised.
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Community dashboards highlighting the local communities’ performance can be established
Subsequent Validation
Subsequent to developing this model, an Engineers Australia (Australia’s peak Professional Engineering body) presentation was attended. This coincidently examined technical and economic aspects of something similar to what is being proposed by cactii. The presenter is Senior lecturer Dr. Terrence Summers of the University of Newcastle department of Electrical Engineering. Below is a link to an excerpt from this presentation. Where he refers to the community shop, think of it as a community pool of energy.
Note that our proposal bears similarities but also does have some differences. The fundamentals are however very close. We have cut out much of the engineering talk and just highlighted the conceptual aspect. Dr Summers does raise some concerns – we believe our solution gets over those issues.
Trading Rules
We are currently considering two option for trading rules, the one being to just pool all capacity in the community and the other being to allow more sophisticated rules with allowance for trading between specific parties.
While it will be up to the member to ultimately decide, a community will initially be started off with the pool concept. when a user is more comfortable with the setup they might to migrate to the more sophisticated trading rule framework below. Typically members would tailor them to suit their own preferences.
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Peers refer to community members who have preferential or specific agreements.This could for example be a club hall with solar selling at very reduced prices or for giving away energy to members of the club.
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Peer Generator – a member with excess energy or stored energy they want certain priority users to receive within a price range;
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Peer Users – prioritize buying from certain providers within a price range.This could community members wishing to support their local sports group;
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Community users will normally just buy within the community group at a certain price range.
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Other Communities will be regarded as community users;
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Grid refers to either the sale of power as a last resort or purchasing as a last resort if price goes over a certain level.Normally the most expensive power and is directly provided by the Retail Electricity Provider to the end user.
Tech architecture
A loose outline of the user technology architecture is
as provided below. Features of this architecture are:
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Communications links using existing on site internet links and an independent 3G/4G link (or LoRaWan) providing independent communications (Independent communications is essential as users networks are not sufficiently stable);
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A tie into the existing local area network allowing the end users at the site to directly access control and reporting without being reliant on the internet;
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Users able to monitor usage, set automation rules and control items directly;
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Onsite energy meter monitoring generated, stored and incoming energy;
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Control unit – allowing for direct on site processing and control.This hooks into the home network but is kept independent as the home network is generally unstable;
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Storage of usage information, configurations within cloud and subsequently separate replication to leave original records untouched for billing purposes;
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Processing of information and generation of indicative net billing by the system and actual processing of information by the Retail Electricity provider to offset community use.