EMMA GVS and approval by Electricity Distribution Network Operators (DNOs).

(updated Feb 2012)

EMMA GVS is approved for use by Western Power Distribution (WPD, UK), Electricity North West (ENW, UK), Scottish Power Energy Networks (SPEN), Scottish & Southern Energy (SSE), Northern Power Grid (formerly CE-Electric) and ESB Ireland (Electric Ireland). For more information, see the links below.

• Map of UK showing what DNO operates where

We are working with the remaining DNOs to confirm approval for the use of EMMA GVS to manage and limit the exports of renewable electricity to their networks. We will happily advise you on getting connection approval from your local DNO – please contact us at +353 1 2108344 or email info@coolpower.ie

Western Power Distribution (UK)

• Example EMMA GVS installation on Western Power Distribution Network
• Extract from Western Power Distribution’s defined approach for acceptance of EMMA GVS

Electricity North West

• Extract from ENW’s defined approach for acceptance for EMMA GVS

Scottish & Southern Energy (SSE)

SSE has approved EMMA in practice for small to medium installations. In April 2012 we will be installing an EMMA system alongside a large wind turbine (50/100kW) to get full SSE approval.

Scottish Power Energy Networks (SPEN)

SPEN has approved EMMA in principle. We are currently in the process of getting EMMA full approval with SPEN through a trial site in Kilmarnock. 

• Example EMMA GVS on Scottish Power’s network: a 15kW Wind turbine limited to 6kW export.

ESB Ireland (Electric Ireland)
EMMA has been approved by ESB in Ireland also under the EN50438 grid connection limitations. We have a number of GVS installations on this network, including in:

• EMMA GVS with 15kW wind turbine, Co. Mayo
• EMMA GVS with 11kW wind, Ballygar, Co. Galway
• EMMA GVS with 13.7kW wind turbine, Kinvarra, Co. Galway

More photos of EMMA on location…

Buyers should be wary of other devices on the market that claim to efficiently manage surplus energy from your renewable generator.

These products may be relatively cheap to buy, but could cost you dearly in the long run – both in terms of your energy bills and energy usage. The fact that these devices are so inefficient is the very reason why Cool Power Products developed EMMA.

What these inferior non-EMMA devices do is:

• Say your generator is producing 750 Watts more than you are using…
• The device spots this and switches on your immersion at full power, i.e. it turns on a load of 3000 Watts (based on a standard immersion heater of 3kW).
• The immersion uses up the surplus 750 Watts from your generator, but because it is fully on, it also needs to draw the remaining 2250 Watts from the grid to make up the difference.
• This means you end up spending more money and using more grid electricity than you would otherwise.
• The reason for this is because these device can only operate the immersion in one of two states: fully on (i.e. needing 3000 Watts), or fully off.
• Conscience of this problem, the suppliers of these other devices sometimes recommend changing the immersion heater to a smaller 1kW one, or using a transformer to reduce its power so the amount of unnecessary electricity drawn from the grid is not so high. However, a 1 kW heater is not a sensible solution – think what happens when your PV system is generating 3.5kW and the household load is 200W – you will be exporting 2.3kW. Even worse, when you press the boost button it will take an eternity to heat up the cylinder with only 1kW being supplied. In contrast, EMMA always ensures that you have hot water, quickly and at the exact times you need it.

Farm moves closer to energy self-sufficiency with the help of EMMA and its 11kw wind turbine.

We have just installed an EMMA TP45 Gaia at the beautiful, 60-acre, West Pitt Farm in Devon. West Pitt Farm is aiming to become self-sufficient for all its electricity, and it already has two wind turbines set on a hilltop above its holiday cottages and eco-lodge. The purpose of the turbines are to provide sufficient power to make the farm’s heated swimming pool carbon neutral and to provide additional power for the site.  The power produced by its Gaia turbine is managed by EMMA.

All 60 acres of West Pitt Farm are enrolled in the Countryside Stewardship Scheme and the farm is managed to enviably high environmental standards. Species-rich grasslands, wetlands and native hedgerows are nurtured by the owners and the farm consequently supports an abundance of rare plants, birds and mammals.

More information, photos and details of the installation will be posted here shortly. In the meantime, check out:

• West Pitt Farm website

Tim Cooper discusses EMMA on Duncan Stewart’s EcoEye programme, broadcast on RTÉ 1 on 24 January 2012.

• EcoEye programme http://www.rte.ie/player/#!v=1132630
  (Starts circa 12 mins in. Available to watch online until 24 February 2012)

• EcoEye website

Graphs showing EMMA GVS matching total farm demand to 20kW PV output.

The data below shows the performance of an EMMA 3G SP15/60 Cascade unit at Deer & Dexter, a venison and beef farm in Cumbria. This data was collected during the day of installation in January 2012 – also the first day of operation.

The EMMA 3G SP 15/60 Cascade is controlling six 3kW immersion heaters (18 kW in total) on a single phase circuit.

This EMMA GVS is on the ENW (Electricity North West) network. Additional data on the performance of the system will be posted here periodically.

20kW PV, managed by an EMMA SP15/60 GVS

The first graph shows EMMA keeping the site demand in line with the output of the 20kW PV system:

Above: EMMA 3G Cascade Unit in operation at Deer ‘n Dexter Farm, Cumbria. The Green line shows total site demand; Red line shows PV output; Dark red line shows % hot water heater.

The second graph, below, shows the water being heated by surplus PV power until 5pm (sunset):

Above: EMMA diverting surplus power to hot water to prevent unnecessary export

EMMA SP15/60 installed at Deer & Dexter

With thanks to Deer & Dexter for allowing us to use the photos and data from their farm and EMMA installation. Check out their website at www.deer-n-dexter.co.uk

EMMA enables farmer to avoid over £25,000 of network upgrade costs when connecting solar PV system to grid.

One of our customers in the UK recently applied to connect a 20kW solar PV system to the grid. However, a system study carried out by the local electricity network operator (DNO) determined that the existing low voltage infrastructure in the area could not accomodate the full export capability of the proposed generator without system reinforcement work by the DNO (addition of a pole mounted transformer change).

This work would be charged on to the customer at £25,000 + VAT.

However, the DNO deemed such upgrade work unecessary if the customer used an EMMA GVS to connect the PV array to the grid.

This is because the EMMA unit will ensure that the PV array always complies with the Agreed Maximum Export Capacity (MEC) set by the DNO to suit the existing electricity network infrastructure – so the network would never be overwhelmed, even without the upgrade work.

Upfront Savings

Less the cost of the appropriate EMMA system, the resulting immediate, upfront savings to the customer are of over £19,000 plus VAT – due to the avoidance of network upgrade costs.

Ongoing Savings

Thereafter, we estimate that the ongoing annual saving to the customer will be about £800. This is on the basis that the EMMA system will enable the customer to use an additional 50% of the energy produced by the PV system on the farm – electricity that would otherwise be automatically exported (i.e. 8,000 kWh at c.10p/unit).

EMMA works with any size generator – micro, small, medium and large. Use the tables below to identify which EMMA model will work best for your renewable generator system.

EMMA 3G – new Cascade system
Used in Cascade formation EMMA can manage loads of up to 27kW on single phase (SP models) and 81kW on three phase (TP models). The Cascade solution is also stackable to manage any multiple of these loads. For instance, to manage a load of 240kW you would stack three TP45/135 Cascade systems.

GVS Models
GVS (Grid Voltage Stabilisation) models of all units are also available. EMMA GVS units function in the same way as standard EMMAs, with the added ability to limit electricity exports to that allowed by your local electricity Distribution Network Operator (DNO). It can be used to limit export to G83 and EN50438 levels by using existing heat loads and where necessary secondary ‘alternative’ heating loads.

• EMMA 3G Sizing Guidelines (PDF, 2 pages)

EMMA creates little or no harmonics on the DNO’s network.

Harmonics and Conducted Emissions test results for EMMA 3G are available below.

These tests were conducted in December 2011, on a random sample unit of EMMA 3G before shipping.

The results show that EMMA does not impact the DNO’s network with harmonics, when compared with the existing harmonics on the network without EMMA 3G.

The test results are from zero to one hundred percent in ten percent increments as requested by the DNO we carried out testing with.

Harmonics Results:

• Full load without EMMA

  With EMMA:

• 3kW test at 10%
• 3kW test at 20%
• 3kW test at 30%
• 3kW test at 40%
• 3kW test at 50%
• 3kW test at 60%
• 3kW test at 70%
• 3kW test at 80%
• 3kW test at 90%

Conducted Emissions Test:
A Conducted Emissions test to EN55022 Class A standard was also carried out on the random test unit:

• Conducted Emissions test results

Hot water, wood drying, quad bikes… our most fascinating project yet.

Our largest system to date was installed this November on an Organic Dairy Farm near Appleby, Cumbria.

Three EMMAs and 42kW of solar PV

The system consists of 42kW of solar PV on the roof of a cattle shed that was built to spec to hold the weight of the array.

42kW of solar PV, managed by an EMMA 3G Cascade GVS system

This three-phase system uses 3 Fronius Inverters one on each phase feeding back to the grid. (EMMA three phase systems are normal single phase systems multiplied by three.)

Love Solar were the installers who took this progressive step with Cool Power Products to design and install our largest system yet. The farmer had a uniquely efficient setup on site for water heating that has been significantly improved by installing EMMA Cascade GVS.

Dairy heater

The three EMMAs (centre of photo), mid-installation.

On one phase is the Dairy heater which is used on a daily basis to washout all the Milking equipment with superheated water:

• This water begins its life being fed into a buffer cylinder that is heated to 45°C by a heat exchanger used for cooling the milk.
• This warm water is then fed to a second tank with three immersions making up to 9 kw/h of heat. that are supplied by EMMA and 2 cascaded SSRs. This second tank however is only fed with water from the buffer cylinder during a set period each day when a timed valve is opened to let the warmed water in (e.g. after wash down in the morning). At this point EMMA uses the power created by the PV array on that phase to heat the water to a specified temperature to kill all bacteria during the washdown.
• During the night time hours the Timer function on EMMA is used to heat the tank to the specified temperature using the Economy 7 rate electricity. This is the most cost effective and efficient way we have seen to heat water.

Buffer Tank

The three EMMAs photographed as the system nears completion.

On another Phase there is approximately 3000 litres of a buffer tank to heat the house and also the hot water:

• This is heated by a Wood Log boiler but also has 4 x 3Kw immersions on the tank that are controlled by a second EMMA GVS cascade system with 2 SSRs.
• The system can heat the tanks water using the electricity created from the PV panels and significantly reduce the amount of wood burned to heat the house as well as free up some time for the owner from frequent reloads of the Wood Log boiler.
• In a similar fashion the EMMA unit can make use of its timer function to heat his boiler during the cheaper night time tarriff when there is no sun for the PV.

Wood Drying Shed & Quad Bikes

On the final phase there is a wood drying shed where all the wood is stored to dry out for use in the wood log boiler mentioned previously:

• The EMMA on the this last phase is designed to drive 4 x 3kW air heaters using EMMA Cascade GVS with 3 SSRs.
• It is quite possible in a final twist to this extremely environmentally friendly install that one of these cascaded SSRs will be changed and used as a charger for an electric quad bike.

EMMA Keeps Grid Voltage Steady

The Fronius inverters used in the EMMA system.

Because of the size of the install the Grid Voltage Stabilization (GVS) mechanism built in to each EMMA unit through its AC transducer will keep the grid voltage steady on site and help eliminate overvoltage outages of the inverters thus boosting the output of an install this size.

This install is on the Electricity North West Network.

Our Biggest Project So Far…

This has been the most fascinating install that Cool Power Products have ever been involved in. So far it is the biggest three phase system we have designed and shipped, but possibly not for long, given the level of interest in EMMA GVS.

Find out more about EMMA Models .

New EMMA 3G harnessing monstrous Loch Ness winds for heating and water.

The latest version of EMMA – a new EMMA 3G Cascade unit – has been installed with 3 Evance wind turbines in Inverness on the banks of Loch Ness.

EMMA 3G helping to harness wind power at Loch Ness

Enviko are the installers who delivered this project in association with Evance Wind, alongside Cool Power Products.

The three EMMA 3G units are sending power to immersion heaters and storage radiators in three separate houses with three separate turbines.

Two Cylinders

The first install has EMMA sending power to two cylinders, using its Cascade capability:

• EMMA acts as a normal EMMA unit while there is surplus power between 0 and 3kW from the Evance turbine, sending this power using the EMMA variable PWM output to one cylinder.
• If the power exceeds 3kW from the turbine – which is a typical scenario on site – the EMMA ramps down power to the first cylinder and engages its SSR to send a straight 3kW to the second cylinder in the house.
• Any excess above this 3kW is then sent to the first cylinder directly from EMMA using the variable PWM output again.

Evance wind turbine using EMMA 3G on the banks of Loch Ness.

The schematic below describes the installation and gives an indication of what can be achieved with EMMA Cascade:

• EMMA 3G Cascade with Evance turbines heating two cylinders

This is the first Evance turbine using EMMA 3G to harness wind power for heating.

Cylinders and Storage Heaters

The other 2 EMMA units in Loch Ness have been used to heat water in a cylinder and switch over to heat a storage radiator once the cylinder has reached its temperature.

The Site makes use of Economy 7 electricity so, while still straightforward, this installation needed to have a little attention given to the positioning of the CTs and also to the switchover mechanism between the hotwater tank and the storage radiator.

This is easily achievable, as demonstrated in the schematic below, using standard components from electrical wholesale:

• SP15/45 Cascade with 5kW Wind feeding Immersion and Alternative Load (Storage heater)

The extra components are a 230v Dual Pole Dual Throw relay meaning the power source can be either direct mains or EMMA to the cylinder or the Storage radiator.

Evance turbine using an EMMA at Inverness. Loch Ness is to the right of the photo.

The DPDT relay is power by a clamp on stat that is closed when the temperature of the cylinder is below the desired hot water temperature.

This keeps the relay engaged sending EMMA power to the cylinder and Economy 7 power to the Storage Rad.

Once the stat disengages the Relay switches over to its alternate poles, disengaging power to the cylinder entirely and switching from Economy 7 to EMMA power on the Storage Rad.

Clever simple applications

There are many more clever simple applications that can be achieved with EMMA using standard electrical equipment to help maximise the free power output from EMMA to heating devices.

On a side note the EMMA’s timer can be used to turn on the heat at any point (e.g. follow Economy 7 times) or by simply using the boost button if renewable heat is not sufficient.

EMMA 3G Cascade installed at Inverness. EMMA is at the bottom right of the photo.