Frequently asked questions

The most common questions people have are below, but please feel free to get in touch if you have any questions of your own.

What is Demand Side Response?

Demand Side Response, or DSR for short, addresses the challenges currently facing the UK electricity market.

As we decarbonise our energy supply and switch to renewable alternatives, the margin between peak electricity demand and supply is at an all-time low, creating the risk of power cuts.

This increased reliance on intermittent renewable wind and solar electricity generation creates fluctuations that make it difficult for the National Grid to balance supply and demand. DSR is therefore part of the balancing solution that National Grid ESO deploys when supply is running short relative to demand. At these times, it calls on a market “response” in two ways:

  1. Extra electricity from local sources – diesel generators, local mini-power stations and battery storage facilities
  2. Reduced demand from organisations who can offer reductions in their own electricity consumption at peak times

This second method is the type of DSR delivered by OakTree Power. We act as a DSR aggregator by using a technology for reducing energy use across a network of commercial buildings for specific time periods. These are called DSR events and put simply, we are enabling building systems to act as distributed energy assets on the electricity grid.

How does it work?

In response to incentives or signals from the UK energy markets about a supply shortfall, OakTree Power uses its novel digital technology to instigate DSR events and adjusts your facility’s electricity consumption a small amount for a short period of time.

When implemented, these events help National Grid ESO to avert crisis situations and as a result they are willing to pay the participants for their contributions. So, by implementing DSR on your behalf, OakTree Power not only generates a revenue stream for your company, but also delivers reductions in CO2 emissions in your property, and savings on your energy bill.

What is Flexible Load

The level of Demand Side Response (DSR) we can offer from your facility depends on the degree of adjustment in electricity consumption we can achieve from equipment such as pumps, chillers, compressors and fans – which we call its Flexible Load.

It’s important to know that we will never adjust essential equipment such as PC’s, lifts and lights.

What happens during a DSR event?

Our Box-on-the-Wall technology interfaces with the Building Management System in your building to instruct it to lower electricity consumption of energy from non-essential plant and equipment such as pumps, chillers, compressors and fans where usage can be lowered for a short period of time, with no adverse effects on the building’s environment.

When the signal is provided to the Box-on-the-Wall to implement a DSR event, it instructs the Building Management System to implement the previously agreed load adjustment strategy, turning down the various items of plant and equipment.

How will the DSR event be felt?

A DSR event will have no impact on the operational running of your building or comfort conditions of the people working in it. In fact, the staff will not notice any difference.

What does my building need to access the benefits of DSR?

OakTree Power is able to offer DSR to a wide range of non-domestic buildings across numerous sectors including offices, hotels, higher education, refrigerated storage and manufacturing. It depends on how the building is being used, but as a rule of thumb, the threshold at which DSR becomes viable would be typically for those buildings in excess of 40,000 sq. ft with an average electricity bill of ~£20k/month and fitted with a modern BMS.

Click here to use our calculator to see the level of benefits available to your building. (You will need some idea of your building’s monthly energy bill.)

How long does a DSR event typically last?

A DSR event takes place for between an hour and two hours at a time, enough to achieve the reductions and savings required, but not sufficient to have any negative impact on building operation or comfort conditions for occupants.

Events are implemented intermittently, triggered by signals from the grid operator when seeking additional support from the market. This could typically be three times a week throughout the year.

What does it cost to fit DSR in my building?

Our DSR system requires no capital outlay because OakTree Power funds the original installation. Once operational, DSR becomes a source of incidental income which, through a gain-share arrangement, allowing us to fund these costs and the ongoing management and optimisation of the DSR events.

The revenue stream is shared with the building owner and may also provide a source for investment in further energy-reduction programmes to achieve additional CO2 emissions reductions and financial savings.

In most cases, we require a five-year contract period for both parties to achieve maximum benefit from DSR participation.

How long does it take to complete the installation?

Fitting OakTree Power’s Box-on-the-Wall normally takes about half a day followed by an hour or two to conduct a final User Acceptance Test to check that the system works by running a test DSR event.

The electricity in your building does not need to be turned off, so the installation is made without disruption.

Why should my company implement DSR?

DSR provides a range of benefits:

  • It helps your organisation to reach its carbon reduction targets, while providing a critical tool required for the UK to meet its own (legal) commitment of achieving Net Zero carbon emissions by 2050.
  • It generates an ongoing passive income which can be reinvested or put towards other CSR activities, to deliver social value.
  • There is no capital outlay required, so the ROI is more attractive than virtually any other energy-saving measure

How large are the DSR benefits?

Click here to use our calculator to see the level of benefits available from your building. (You will need some idea of your building’s monthly energy bill.)

What do we need to do to get DSR installed in our building?

Fill in the contact us form for a free assessment of your building’s suitability for DSR.

Who owns the DSR box and what happens if it needs maintenance or repair?

OakTree Power absorbs all costs for the DSR installation and is responsible for its ongoing performance and so retains ownership of the technology during the period of the contract.

The box-on-the-wall has a mean time to failure (MTF) of over 12 years. If an issue does arise, OakTree Power employs a ‘rip and replace’ approach, removing the main controller unit and replacing it with a new one, quickly and with minimal down-time to ensure benefits are maintained.

What happens if we vacate or sell the building before the end of the 5-year contract?

As the DSR service is provided as a no-cost source of incidental income along with reduced CO 2 emissions and electricity costs, it would be assumed that the new owner would want to retain it. In this case, OakTree Power’s service contract could easily be novated to the new owner. OakTree Power is able to provide its DSR solution at no-cost by funding it throughout a five-year term. If the contract was ended early, a termination payment would be due for the balance of the contract term.


NGESO – National Grid electricity system operator: As the system operator, they are required to make offers to parties seeking connection to the national electricity transmission system (NETS).

BMS – Building Management System: is a computer-based control system installed in buildings that controls and monitors the building’s mechanical and electrical equipment which may include ventilation, lighting, power systems, fire systems, and security systems. The OakTree Power box-on-the-wall interfaces with the BMS to deliver DSR events.

Flexible Load – The degree of adjustment we can achieve from your facility’s electricity consumption.

Net Zero – Means achieving a balance between the greenhouse gases put into the atmosphere and those taken out. This state is also referred to as carbon neutral; although zero emissions and zero carbon are slightly different, as they usually mean that no emissions were produced in the first place. The UK has a legal commitment to be carbon neutral by 2050 and many organisations are following this lead by setting their own Net Zero targets

Carbon Neutral – this refers to achieving net-zero carbon dioxide emissions. This can be done by balancing emissions of carbon dioxide with its removal or by simply eliminating emissions from society. Going beyond this, it is possible to become carbon negative, where an entity’s carbon footprint is less than neutral. This can be achieved through processes that have a net effect of removing carbon dioxide from the atmosphere such as carbon capture but more typically is achieved through carbon offsetting projects, such as tree planting.

Decarbonisation – the reduction of carbon dioxide emissions through moving away from carbon emitting sources and achieving a lower output of greenhouse gasses into the atmosphere. The UK strategy to decarbonise the economy has resulted in the move to renewable energy generation in place of coal-fired power stations and a switch from petrol and diesel cars to EVs.

Load Adjustment Strategy – this is the pre-agreed plan for consumption reduction, programmed into the Building Management System and initiated by the box-on-the-wall when the signal is received to implement a DSR event.

Aggregator – OakTree Power is a DSR Aggregator. We are a new type of energy service provider, working with a raft of clients to reduce or moderate the electricity consumption of that group, according to total electricity demand on the grid. DSR revenues are possible because OakTree Power aggregates its service across many end users to achieve the threshold necessary to interact with National Grid ESO.

System charges TNUoS (Triad) and red zone DUoS)

TNUoS – charges applied to recover the cost of installing and maintaining the transmission system in England, Wales, Scotland and Offshore. Depending on your tariff, OakTree Power can help reduce some of these costs as part of the DSR management process.

DUoS – DUoS is part of your overall electricity bill and includes both a fixed charge (mainly based on your contracted connection capacity) and a variable charge that applies to every kWh of consumption. DUoS covers the cost of installing and maintaining local electricity distribution networks, which transport electricity from the National Grid to your business.