Synergy Module

I am planning to turn my home into a little energy test laboratory so I can experiment with Off Peak Synergy Module concepts at the domestic scale. I have installed a 500 litre insulated stainless steel tank to store hot potable water. I will install a further 1000 litre insulated tank to store central heating water. These tanks mean that I can store enough hot water for one day for both washing and central heating.

I will install a large solar panel to heat the water in both tanks. I will supplement this solar heating with a water to water heat exchanger which will be electrically operated using off peak energy. In the winter this heat exchanger will take heat from a glass covered swimming pool. In the summer, after both tanks are full of hot water any surplus heat will be transferred to the swimming pool.

Karen and I bought this house nearly two years ago and it has oil fired heating which I will now replace. Living in the country, I have access to waste timber so I bought a wood burning stove and installed it in our living room. In return for some work this will give about another 5kW of heat for evenings where the heat pump cannot cope with very cold weather.

It takes 1kW to raise 1 litre of water one degree C in one second. Therefore a 3kW output heat pump would require 167 seconds to raise the temperature of the water in the tank by 1 degree C.  This means that a 3kW energy supply would require about 2.5 hours to raise the water in the tank by 50 degrees C. Therefore this potable water tank can be seen as a 7.5kWh energy storage device. Our larger water tank for heating can be seen to store 15kWh of energy.

I drive a Toyota Prius car. I am interested in various articles that talk about plug in hybrids and I plan to purchase a kit to convert my hybrid to a plug in. I then expect my Synergy Module to charge my car each night with low cost electricity.

As Ireland has an abundance of sites for commercial wind energy exploitation, I see no ecological advantage to installing a wind turbine at my home. However if PV solar panels drop in price I am hoping that my Synergy Module may trade some high cost day time electricity for low cost night time electricity and reduce my overall energy bills. 

The work that Google are doing on solar energy and hybrid cars is fascinating. Reading the following blog from Google though adds a new element to the mix.

http://googleblog.blogspot.com/2007/06/clean-energy-update.html

Google are growing a fleet of plug in hybrid cars. These are standard hybrid cars with larger batteries fitted and the ability to charge from the electricity grid. The blog also mentions vehicle to grid (V2G) technology. This allows the bidirectional transfer of electricity between the electricity grid and the plug in hybrid.

In the context of Ireland’s need to consume surplus wind generated electricity, electric vehicle or hybrid vehicle batteries would be an ideal candidate for energy storage where the stored energy replaced fossil fuels when consumed on the following day. According to the Irish Examiner (19 June 2007), Toyota are selling 400 Prius hybrid cars per annum in Ireland. Obviously the installed base would have to be much higher to have a significant impact on grid stability.   

Last Friday, 8th June 2007, Eirgrid published a paper on Wind Powered Generation which was subtitled ‘An analytical framework to assess generation cost implications’.

http://www.eirgrid.com/EirgridPortal/uploads/Announcements/Windreportv.16.pdf

The report is a very competent analysis establishing the relative cost of electricity generated by wind energy versus by natural gas. The wild-card variable in this analysis is, of course, the variability in price of natural gas from now to 2025 the period of analysis in the report. I was very confused by the predictions for natural gas prices and so I sent EirGrid a question regarding same. The question and their answer are shown below. It’s very interesting that natural gas prices more than doubled and then halved again in one year. No wonder I was confused.

Question

I am studying the energy market in Ireland to identify business opportunities. I need your help understanding one issue. I just read your report about the relative cost effectiveness of wind energy.The report comes out very neutral on the topic. Wind is OK in small doses but we can’t have too much because it destabilises the network. Fair enough! But the whole case of the document was comparing wind to natural gas. The authors had to estimate what the price of natural gas is going to be from now until 2025 to do the sums. They had three scenarios, best, worst and most likely. A consultancy group, Popry, was quoted as a reference for these price estimates.By my interpretation of the natural gas price prediction graph in your report:-

The price forecasts are based on a period when there was a gas supply shortage in the UK. This had driven prices to historically high levels of 80 cent/therm. The forecast was that these prices would fall back again once additional gas pipeline capacity from Europe to the UK was commissioned in early 2007. So far the predictions have been correct with gas prices now down to 30 cent/therm or less (on the UK gas balancing market).  The low gas price scenario continues on at this low level based on the UK ‘s ability to tap into the global gas market through the construction of large scale LNG terminals.  In the long term if gas prices went to the higher levels quoted, you may see some switching to clean coal technology for electricity generation.

The paper identifies the break even price of gas to be above 80 cent. The reader can then take a own view on the probability of average gas prices over a year being in excess of 80 cent. In the long term as fossil fuels get scarce, it is fair to say that prices could be expected to rise, the unknown is by how much and when.

The following graphs contain the actual electricity demand and actual wind energy demand curves for 16th February 2007 for Ireland. The third in the series plots the percentage of the national grid that was supplied on that day by wind energy. The raw information was downloaded from the archives of www.eirgrid.com, the Transmission System Operator (TSO) in Ireland.

You can see that wind production went from nearly 20% of demand to almost 0% of demand in one day and worse of all was the fact that it did so completely out of sync with the demand usage curve. Wind energy supply and electricity demand were not matched. This mismatch creates difficulties for network operators because, apart from limited pumped hydro storage capability, electricity cannot be stored and it takes time to start and stop fossil fuel burning electricity burning stations. Also, because of the unreliability of supply, it is necessary to have enough non wind based capacity to meet maximum demand.

Despite the green credentials of wind energy there are problems with its implementation. If wind energy production, in Ireland, is to rise higher than its current 4%. We will have to implement either pumped hydro storage or demand management. Demand management is cheaper and faster to implement and I believe it is the necessary option for Ireland. Perhaps there is a place for pumped hydro storage also.

Current pumped hydro storage capacity in Ireland.

As far as I am aware, there is only one pumped hydro storage facility in Ireland. This is located at Turlough Hill http://www.esb.ie/main/about_esb/history_turlough.jsp

Current demand management projects in Ireland.

The following pdf presentation gives an overview of current EDM schemes in Ireland.

www.sei.ie/getFile.asp?FC_ID=2946&docID=302

Ireland has a unique characteristic from an energy perspective.  We have the best wind energy of any location in the world but we are unable to exploit it because of the mismatch between demand and supply. There is no flexibility in wind energy supply and to date there is very little flexibility in electricity demand. This problem is very well described in ‘Pumped Hydro Energy Storage to Support Wind Energy Penetration in Ireland’. Currently this paper is available at :  http://www.ucc.ie/serg/pub/PS-R2.pdf

Recently there has been significant interest in and investigation of pumped hydro energy storage in Ireland. I have not heard mention of the the use of energy demand management (EDM).

There are two organisation in the USA to support professionals and companies involved in energy demand management :-

1. The Peak Load Management Alliance   http://www.peaklma.com/
2. Demand Response and Advanced Metering Coalition   http://www.dramcoalition.org/

The most publicly visible commercial organisations in the US involved in EDM are EnerNOC Inc. (www.enernoc.com) and Comverge Inc. (www.comverge.com). Enernoc currently claim to have 650MW of customer owned diesel generator power under their control for grid stabilisation. Comverge claim to have 4.5 million demand management modules installed.

Although there is a place for both, I believe that EDM is a better solution for grid stabilisation, than pumped hydro, in Ireland for three reasons:

1. It has very low capital cost because it uses existing resources
2. It does not have the losses (typically 20-25%) or capacity limitation of pumped hydro
3. It can contribute to carbon emissions reduction when combined with a bio-diesel / FAME/ PPO project

The Irish Examiner today reported that the ESB (www.esb.ie) had sold its CHP subsidiary, Ballyragget Power, to Dalkia (www.dalkia.ie).

Ballyragget power operate five CHP plants in Ireland which generate 19 Megawatts. The plants are located in Kilkenny, Waterford, Cork and Dublin. The plants include one each at UCD (www.ucd.ie) and UCC (www.ucc.ie).