And what whole-home coordination actually looks like
Virtual power plants were supposed to be the smart solution for the modern energy home.
Connect your battery. Let the software take over. Earn money while the grid stays balanced. Simple.
The reality, for a growing number of UK homeowners, is proving more complicated.
On the MoneySavingExpert forum, one Powerwall owner recently described their experience after joining a VPP: "I fear that my battery is being drained and recharged in ways that do not offer me as much as when I had fixed rates for import and export depending on time of day."
This is not an isolated complaint. It is a structural problem — one that goes to the heart of what VPPs are designed to do, and who they are designed to serve.
What a VPP actually optimises for
A virtual power plant is, at its core, a grid asset.
It aggregates thousands of home batteries, EV chargers and flexible devices into a single controllable resource. When the grid needs demand response — a cold January evening, a sudden drop in wind generation, a frequency event — the VPP operator dispatches the fleet. Batteries discharge. Chargers pause. The grid stabilises.
Axle Energy, one of the UK's newer VPP operators, is refreshingly honest about the arrangement: if you join, you give up all control of your battery to Axle — and in exchange you won't have to lift a finger as the earnings arrive. The current offer is £1 per kWh during stress events, with a guaranteed minimum of £10 per month.
Let's be fair to those numbers: £120 a year guaranteed, for doing nothing, is genuinely attractive. For some households it will be the right choice.
But that sentence — give up all control — contains the entire trade-off.
The VPP operator's incentive is grid stability and balancing market revenue. Your battery is the instrument through which they achieve that. When those two things align — when what's good for the grid is also what's good for your home — the system works well. When they don't align, the grid wins.
And here's the arithmetic the headline payment doesn't show. If a 5pm dispatch leaves your battery depleted just before your own evening peak, your home replaces that energy from the grid at peak rates. On a tariff where peak import costs 25p/kWh more than the overnight rate, refilling 10 kWh of displaced energy costs you £2.50 — in one evening. A handful of badly timed dispatches per month and the £10 minimum payment has been quietly eaten by your own import bill. The payment is visible. The cost is not.
That's why homeowners on forums report the feeling of being worse off without being able to point to exactly why. The earnings arrive as a line item. The losses arrive disguised as a slightly higher bill.
The fundamental misalignment
VPPs are not designed to optimise your home. They are designed to optimise the grid using your home.
That distinction matters enormously in practice.
A VPP sees your battery as one node in a fleet of thousands. It dispatches based on what the aggregate fleet needs. It does not know that you have solar generating surplus this afternoon. It does not know that your EV needs to be fully charged by 7am tomorrow. It does not know that your heat pump will create significant demand this evening.
Even well-intentioned VPP operators — and most are — cannot optimise for your specific home, because they were never designed to. Their optimisation objective is the grid. Your home is a means to that end.
As one homeowner put it: "I'm sure you can make more if you manage the system yourself."
They're right. But managing it yourself means becoming your own energy trader — tracking half-hourly prices, monitoring solar forecasts, manually setting charge and export windows, adjusting for weather, for usage, for seasons. That is a part-time job most people don't want.
The choice, as it currently stands, is between giving up control to a system that doesn't optimise for you, or retaining control and doing it manually.
Neither is the right answer.
Haven't smart tariffs already solved this?
Partially — and it's worth being honest about that.
The best smart tariffs already do single-device coordination well. Intelligent Octopus, for example, schedules your EV charging around a departure time and minimum charge level you set, and shifts the charging itself to cheap overnight windows. That is real progress, and for a household whose only flexible asset is an EV, it works.
But it is one device.
The moment you add solar, a home battery, and a heat pump, single-device intelligence hits its ceiling. The EV scheduler doesn't know your battery's state of charge. The battery doesn't know the heat pump is about to draw three kilowatt-hours. Nothing is deciding whether this afternoon's solar surplus should go to the battery, the car, or the grid — that outcome is just whatever the devices' separate default behaviours happen to produce.
Smart tariffs solved the when is electricity cheap problem. They did not solve the what should my whole home do about it problem. Those are different problems, and the second one is where the remaining money sits.
What whole-home coordination actually means
The problem with VPPs is not that automation is wrong. Automation is exactly right. The problem is that the optimisation objective is wrong.
A system that genuinely works for the homeowner has a different set of priorities:
The home comes first. The EV has the charge the driver needs. The heat pump maintains the comfort level set. The backup reserve is protected. Non-negotiable constraints are set by the homeowner and never overridden.
Every device is considered together. Solar generation, home battery state, EV charge level, heat pump demand, tariff pricing, grid carbon intensity — all inputs to a single decision. Not five separate systems making five separate decisions. One coordinated strategy across all of them simultaneously.
The tariff is read in real time. On Octopus Agile, prices change every 30 minutes. The cheapest hours to charge, the most expensive hours to avoid, the export windows worth capturing — these shift daily and require continuous optimisation.
Weather and generation are forecast, not assumed. Knowing that tomorrow will be overcast changes every decision made tonight. A genuine coordination system reads solar forecasts, adjusts expected generation, and plans overnight charging accordingly.
The homeowner sets outcomes, not settings. Save as much as possible. Keep the car ready by 7am. Maintain 20°C minimum in the house. Preserve 30% battery backup. The system handles everything else — every decision, every 30 minutes, without the homeowner needing to think about it once.
What this looks like in practice
Here is the difference between a VPP-controlled home and a coordinated home on a typical winter day:
The VPP home receives a dispatch instruction at 5pm — a grid stress event. The battery discharges to support the grid. The homeowner earns the stress-event payment. But the battery is now near empty as the household's own evening peak arrives. The heat pump runs its evening cycle. The home pulls from the grid at peak rates — paying back a meaningful share of what the dispatch just earned. The car charges overnight at the tariff's standard off-peak window, with no awareness of what the rest of the home needs from that same energy budget.
The coordinated home sees the afternoon prices, forecasts tomorrow's solar, knows the car needs 40 kWh by 7am, knows the heat pump will draw 3 kWh this evening, and builds a plan. The battery is reserved for evening peak coverage. The car charges in the cheapest overnight slots. The heat pump pre-heats before the expensive window opens. The homeowner wakes up with a full car, a warm house, and a battery still holding reserve — ready for whatever the day brings.
No stress-event payment was earned. But nothing was paid back at peak rates either, no comfort was compromised, and the car was ready. The headline payment looks attractive. The whole-home economics tell a different story.
Can a home do both?
Yes — and this is where the market is heading.
The right architecture is one where the homeowner's constraints are set first, always, and treated as inviolable. Within those constraints — the car is charged, the comfort is maintained, the backup is preserved — the home can participate in grid flexibility services and keep the revenue without sacrificing its own economics.
Grid participation on the homeowner's terms, not the aggregator's.
This is not how current VPPs work. It is the direction Aveum is building toward — coordination first, grid revenue layered on top of it, never instead of it.
The home comes first. The grid gets what's left over. The homeowner earns from both.
The bottom line
VPPs are a genuine and important part of the clean energy transition. The grid needs flexible demand. Home batteries are a real and valuable resource. The concept is sound, and for some households today, the guaranteed payments are worth it.
But the current implementation asks homeowners to hand over control of their most valuable energy assets to a system optimised for someone else's objective — and to absorb costs that never appear on the same statement as the earnings.
The alternative is not manual control. That's too complex, too time-consuming, and unnecessary given what software can now do.
The alternative is whole-home coordination — a system that sees every device, reads every signal, forecasts every variable, and makes every decision in the homeowner's interest. Automatically. Every 30 minutes. Every day.
That is what Aveum is building.
Not a grid asset management tool. A home energy operating system — one where the homeowner sets the outcomes and the software handles everything else.
Your devices. Your priorities. Optimised for you.
Fix it with Aveum
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