Generating interest in EMMA

The energy and micro-generator manager (EMMA) is a device that is installed alongside a micro-generator for hydro, PV or wind. It monitors in real-time what your micro-generator is producing and what energy you are using in small commercial buildings or households. If it detects there is surplus electricity available it then diverts this to an immersion heater for the production of hot water or similar resistive load device. This energy can then be stored and used when required.

The EMMA is beneficial as between 45%, and in some cases 80%, of what you generate is exported to the grid because of the miss-match between the electricity generation and the demand profiles. EMMA matches these two curves. Up to 40% of household energy requirements are for hot water and so the excess electricity is usually put to good use satisfying this requirement. Over 60 devices have been installed across Ireland and the UK.

The young EMMA

EMMA was developed over two and a half years ago in Ireland where there was no export tariff for any electricity put into the grid from a micro-generator. Prior to development we had searched worldwide to try and find a similar technology, but as none was found we decided to develop it ourselves.

The unique technical feature of the EMMA is that it seamlessly ramps the electricity up and down to the immersion heater (or similar resistive load device) using patented control technology. This may seem a simple solution but it has taken many thousands of hours of development time. In some countries the technology is financially very attractive. For example, in the UK you only get 3pence per kWh exported and so it makes sense to use the electricity in the house rather than re-import it later. You receive the feed-in tariff based on what you generate, not what you export. This is not impacted by installing EMMA.

There are a variety of uses for EMMA, which include:

• In any country where the export tariff for electricity is low or zero.

• Any house/small commercial/school with more than 1kW micro-generator with immersion/ hot water tank.

• Install with micro hydro, PV or micro wind.

• Where client wants a micro-generator and a thermal solar system. Put EMMA instead of thermal solar at 30% of the costs.

• Where hot water is produced from electricity/gas/oil central heating and uses a hot water cylinder.

• Up to 30kW (larger units are bespoke).

• Grid connected - three phase or single phase.

The main benefits of using EMMA technology are that you can significantly increase the rate of return on investment in your micro-generator; help stabilise the distribution network; and further reduce reliance on fossil fuels.

Figure 1 shows actual data from a site where an EMMA is installed. There is a significant miss-match between the demand and generator output profiles. This is typical of most sites where we have installed EMMA and have been able to monitor this data.

Figure 2 shows the same site with the EMMA switched on. Here the profiles are matched perfectly within the operating constraints of the generator. There are some times where the overall demand is higher than the output from the generator. In this case the EMMA ramps the immersion to zero and some electricity will be imported to the household.

Effectively the energy produced from the micro-generator is prioritised. First use is always allocated to the household. Secondly to the hot water production, if required, and thirdly to export to the grid. This ensures the most effective payback for the user.

The EMMA can be used with other technologies and has been connected to storage heaters and electric underfloor heating systems. It comes in a standard range of sizes from 4kW single phase up to 30kW three-phase phase systems. We can do larger devices but these would be bespoke designs.

Micro hydro installation

We recently installed an EMMA with a 3.7kW micro-hydro generator in Andover, Hampshire, UK. This exciting project has been a great success. The client restored a 90-year-old turbine which had remained idle for many years. On this site the client installed two heat storage systems, one for his domestic hot water and the second for the central heating. When there is excess electricity available it is put into the domestic hot water cylinder first, when this is full it then starts to heat the central heating cylinder. The EMMA paid for itself in a matter of months as the client was no longer using his large oil-fired boiler to heat his domestic hot water.

We are planning to install EMMA in a number of other micro-hydro projects in the UK over the next 12 months. Most of these are in remote areas where the EMMA can help further displace fossil fuels and increase the rate of return on the micro hydro investment.

A most exciting and recent development of the product is the development of our grid voltage stabilisation version (GVS) which we are trialling with UK network operators. The EMMA GVS allows you to connect larger micro-generators to the grid in areas where the network operator is imposing limits.

The EMMA GVS monitors the network voltage and the export capacity. It can react by limiting export levels when the voltage is higher than a specified point or simply limit the export capacity. The benefits are that you do not have to pay for a costly network upgrade and can install a larger micro-generator to match your requirements. You also get all the benefits of the EMMA in terms of usage of energy on-site, and reduced imports/costs.

The EMMA GVS can also be used where you have a high concentration of micro-generators in an area. Here the benefits are a stable network and optimised use of the electricity being generated. There are projects underway in the US trying to determine a solution for this type of problem. EMMA GVS is the solution and is already here.

The future offers very exciting opportunities for EMMA technology. For example, we are scoping an opportunity to pilot the use of EMMA in demand side management/smart grids. As you are able to control devices in response to signals sent to the EMMA, or in response to voltage peaks or troughs, it can therefore be used to reduce the cost of electricity supply or stabilise grid networks.

Richard Linger, Director Coolpower Products Ltd, 89 Booterstown Ave, Blackrock, Co. Dublin. Ireland Email: Richardlinger@coolpower.ie

www.Coolpowerproducts.com