The Environment, Self-Sufficiency and Technology Blog
Deeper penetration of renewables onto the electical grid is facilitated by linking regional grids using high voltage interconnects. I am a supported of TREC as you will see from previous posts. I found the following proposal on www.airtricity.com
These interconnects act both as a way of landing electrical energy from offshore wind farms as well as interconnecting the grids on both sides of the link. Full details are available on:-
In the last few days, EirGrid, the Irish TSO, was forced to curtail wind farms because we had too much electrical energy. See the following blog on the subject:-
http://greenmonk.net/demand-response-how-to-get-more-wind-energy-onto-the-grid/
One of the problems with renewable energy is the inflexibility of supply. This inflexibility is the very feature that requires EDM which is the topic of this blog. EDM can only go so far in balancing the supply and demand of electricity. Another technique is to builld supergrids that link broad geographical areas so that meteorological variations can be averaged.
In 2003 the Trans-Mediterranean Renewable Energy Cooperation (TREC) was founded by the Club of Rome, the Hamburg Climate Protection Foundation and the National Energy Research Center of Jordan (NERC). TREC in cooperation with the German Aerospace Center (DLR) developed the DESERTEC Concept of linking African, Middle East, and Northern European states electrical grids into one supergrid using high voltage direct current (HVDC) interconnects.
This is a fantastic idea. I recommend you visit http://www.desertec.org to learn more and to register your approval for the project in their ‘Give TREC Your Voice’ campaign.
This blog is about how EDM can help the penetration of renewable energy sources into the electricity grid in Ireland. Another facilitator of renewable energy penetration is energy storage. For example, currently, there is significant interest in pumped hydro storage in Ireland. I have added the URL of the Electricity Storage Association http://electricitystorage.org/ to the blogroll of this site. This URL lists the many options for electricity storage and draws comparisons between them.
It would seem from the analysis that compressed air energy storage (CAES) is an option that might also deserve investigation in the Irish context. This technology uses underground mines or natural caverns to store large volumes of compressed air. During times of surplus electrical energy, air is pumped into the cavern. When electricity is required, the compressed air is used to improve the efficiency of a gas fired turbine.
Off the south coast of Cork in Ireland is the Kinsale gas field which is operated by Marathon. For full details read the following PDF.
http://www.cer.ie/cer04108.pdf
The Kinsale field is now nearly spent and is being used as a natural gas storage facility. The Seven Heads gas field which extends further into the Atlantic uses the pipline and infrastructure of the Kinsale field to land the gas on shore. I began to wonder could the Kinsale gas field infrastructure be used to implement a CAES system. I decided to send the following email to Marathon’s press officers.
_________________________________________
Dear Linda, Robert,
I would appreciate it if you could supply an answer to a technical question, please.
Question Background: Ireland has a major problem with wind energy penetration due to the variable supply nature of wind generated electricity. Energy demand management (EDM) or energy storage, preferably both, are required to solve the problem. As I understand it, Ireland has 2GW of planning permissions for wind turbines for which grid connections are not possible for reasons of grid instability. I am interested in EDM and energy storage. While researching the technologies behind energy storage I grew a particular interest in the viability of compressed air energy storage (CAES). This form of energy storage is used in conjunction with natural gas to increase turbine efficiency. What is required is a large sealed natural cavern that can be used to store compressed air.
Question: I understand that the Marathon south west gas field, in Ireland, is now being used for gas storage. Could it be used for compressed air storage to help solve Ireland’s wind energy penetration problem?
I would appreciate your feedback on this issue. Please let me know if I can reprint your reply on my blog www.synergymodule.com.
Kindest Regards
Jerry
____________________________________
I look forward to publishing their reply.
19th August 2007
I havn’t heard back from Marathon. I’ll try more local contacts and I will publish whatever reply I get. I think that natural gas wells may not be suitable for CAES because mixing air and natural gas makes an explosive mixture.
In the meantime I found the following two references to the two oldest CAES projects in existance.
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:-
Either I am reading this incorrectly, or the whole peak oil thing is not on Eirgrid’s radar. If you put a 5% increase on gas prices per annum, which I would have thought reasonable) then surely the economics swings hugely in favour of wind energy. Are you really basing your predictions on the worst case expectation that energy prices will increase less than general inflation over the next 18 years? The likely and best case scenarios seem bizarre to me.
I’m totally confused. Can you help? Please explain how I am misinterpreting your report.
Answer
Thank you for your question on our Wind Powered generation paper. We would point out that it is a contribution to the discussion on the issue of the economics of wind generation and has been discussed with industry stakeholders and that we do welcome comment.
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.