Recently in Renewables Category
We are experiencing a cold prolonged winter spell that reaches back as far as 1963 from a historical record beating point of view, As you can see above the weather station recorded lows of -9.6 degrees Celsius. When the wind chill was factored in this brought it down to -13.2 Celsius. Several of my neighbours have no water due to frozen pipes, we are fortunate that our have not frozen yet.
The 45 cm of insulation in the rafters and the 10 cm under the pitch of the roof as well as the filled cavity are doing their part to reduced the chilling effects. There is no easy fix for the state of the roads.
The data can the be uploaded to a website and your wind data can be utilised to assess how much energy you could potentially generate with various wind turbines
The average wind speed in Ireland according to the Irish metereolegical office is 7 - 18 mph. "Average annual wind speeds range from 7 m.p.h. in parts of south Leinster to over 18 m.p.h. in the extreme north."
This converts to 3.12 - 8.04 m/s, I have seen claims by a wind turbine provider that the average wind speed in Ireland is 9.3 m/s - 14.16 m/s. This does not correlate with the met office and should be ignored.
I recently attended a Tipperary Energy Agency training course on RETscreen. The excellent trainers referred to and discussed the vestas wind turbines that are used in wind farms in terms of capacity factor. These range typically in the 30 - 40% bracket as they are placed on well exposed sites.
As explained in the American Wind Energy Association website capacity factor is one element in measuring the productivity of a wind turbine. This figure compares the wind turbines actual production over a given period of time with the amount of power the turbine would have produced if it had run at full capacity for the same amount of time.
e..g a 1.6 kw(rated at 12 m/s) turbine generates 3321.792 kwh of electricity in a year.
If 12 m/s wind was available 100 % of the time then it would have generated 14016 kwh of electricity (8760 hrs * 1.6 kw) . The capacity factor is
amount generated = 3321.792
-------------------- --------------
theoretical amount at full capacity 14016
= 23.7 % capacity
This does not mean that the turbine is faulty it just implies that wind speed of 12 m/s was not available all of the time.
The community wind power fact sheet reports that wind typically has a capacity factor of 20 - 40 % and hydro (water) has a capacity factor of 30 - 80 %. Water is more predictable and makes for a more dependable source of power.
If Company X makes a claim that a turbine can pay for itself in 7 years a crude measurement would be divide the cost of the turbine by 7 and then calculate the
number of units that would have to generated and compare this to the cost of the turbine
e.g. Turbine X sells a 1.6 kw turbine (rated at 12 m/s) for 7000 euros installed, and claims a pay back in 7 yrs. This turbine would have to generate 1000 euros of electricity per year to achieve this.
1000 euros of electricity at 16 cent per unit = 6250 units
The theoretical would be 8760 * 1.6 = 14016 units
Actual production = 6250
----------------- ------------
Theoretical 14016
= 44.6 % capacity
This capacity factor is higher than commercial wind farms and would very difficult to achieve.
According to RETscreen awind turbine at 10 meters would need to have wind speeds of 10.9 meters which is 13.2 at 50 meters. Using a shear factor of 0.12 which is open agricultural land with no buildings nearby. These types of wind speed are very difficult to achieve.
Evance who used to be called iskra market their 9000 turbine which they claim will generate 9000 units per year at the uk mean speed of 5 m/s. Their turbine is rated at 5.4 kw at 11 m/s
Capacity factor = 9000
---------------
8760*5.4
= 19% = 9000 * 0.16 = 1440 euro of electricity per year.
So we have one turbine manufacturer who markets at 44% capacity and the other at 19%.
Personally speaking I think 20 - 25 % is a good yard stick for assessing a domestic turbine
e.g. 2 kw turbine at 25% capacity would produce
(8760 * 2 ) * 0.25 = 4380 units
4380 at 16 cents = 701 Euros per year.
If you want to get your money back in 10 years it should be priced around 7,000 euros.
Hopefully this will assist you in making some rough calculations on wind turbine claims
The outgoing warm stale air, heats the incoming cold air.
It is important to clean and replace filters on a regular basis. Boards.ie has an interesting discussion on this topic and the fact that irish government are going to issue guidelines on this.
1) Scheme covers cavity wall insulation and or attic insulation (in standard pitched roofs....flat roofs / dry lining etc. not covered.) in national schools built before 2006
2) Scheme covers quilt type insulation in attics (fibre glass or rock wool, blown in products excluded) and EPS bead or similar for cavity wall (foam excluded)
3) Scheme covers 100% of the cost
4) School needs to get 3 No. quotations from approved suppliers. Approved suppliers are the same as those registered for SEI HES Scheme
5) On completion school needs to hire engineer, architect or suitably qualified person to verify that work has been carried out (€200 provided by dept to fund sign off inspection)
6) Dept has set out minimum specification to be achieved
See fpisolar.ie and energyeducation.ie for more info
If you are considering building an energy efficient house, I would recommend that you read the whole house book. This book originally published in 1998 but updated in 2008. It covers all aspects of a sustainable building project. With numerous case studies which highlight the improvements that can be made to a structure it shows the reader how small changes can generate big results.
The CAT centre in Wales publish this book, this centre has been implemented "green technologies" since the 1970s, some of which are only becoming mainstream now.
My colleague Bernie Goldbach wrote an article in April in relation to the greener homes supplement in the Sunday Times. This supplement appeared again this weekend (21st June 2009) the articles prompted me to mention this book. There is a renewed interest in sustainable design, this is something we teach and specialise in Tipperary Institute. We use this book as the student text book for our Advanced Certificate in Domestic Sustainable Energy
This article is in the process of being updated with new information from the manufacturers regarding their power curves and the average wind speeds used for their payback calculations,
Met Eireaan report that the wind speeds as being 3 m/s in south leinster- to 8 m/s in the extreme north ( 7 mph to 18 mph) When this is complete the results will be posted.
I am attending the Tipperary Energy Agency training course on RETScreen
RETScreen is a tool used for PreFeasibility and Feasibility Analysis. It is developed by the Canadian government. It requires relatively little user input and calculates the technical and financial viability automatically.
I would like to see RETScreen being used to estimate wind turbine and solar photovoltaic output and return on investment.
I have heard on the news and seen on irish websites claims of payback times for wind turbines of 8 - 12 years. These websites and company reps do not provide any data regarding the calculation or how these figures were derived.
Will these companies who state payback in 10 years, refund the cost of the turbine if after 2 - 3 years it is apparent that the turbine will not pay back in 10 years?
The spurious claims being made by some sales reps at energy shows and on web sites will come back to haunt us in 18 - 24 months, when radio chat shows will be clogged with angry people ranting about the fact that the payback is not being achieved. Do we want the 6 pm news doing a wood pellet type report on domestic wind turbines? The renewable energy sector needs to clean up its act and set standards for sales of renewable products.
How can some one state a payback to a client with out viewing the site?
I learned an important lesson about wind turbines, I measured my wind speeds for 1 year and at least I have factual data to help me make my decision.
Even though I live in a windy area my site is not great. There are better sites out there that are suitable for turbines, but how can the consumer make an informed decision?
We need to measure wind speed first, companies are under pressure to generate sales so if they are competing with cowboys who are telling porky pies about payback, what can they do, do they match their claims?
Any state assisted programme for wind turbines should mandate measurement of wind speed before the turbine is installed. I would recommend 6 months minimum measurement. Consumers should be made more aware about demanding calculations, results etc
Companies should produce factual energy output measurement and recorded data for energy production from at least 5 different sites. Sound levels should be measured from 20, 40 and 60 meters.
As part of a sales quotation companies should include a calculation from an application such as RETscreen which would indicate the kw hrs being produced, this would be backed up with the recorded wind speed analysis.
Some companies can provide data on the output generated by their turbines across different countries and different locations. My instinct is to trust these companies above a company that starts business on a Monday and imports a turbine from China on a Tuesday so as to sell it on a Wednesday.
There are videos on youtube where enthuastic wind turbine installers have installed wind turbines and mentioned the figures being generated. I did my sums and the payback for that installer was 30 years plus. The problem was the site. That same wind turbine would have a payback time of 26 years on my site based on their cost.
The domestic wind turbine is fraught with issues that must be addressed in an open and transparent manner. We have the potential to benefit from this great resource but this can only be achieved using an ethical and honest approach.
If you are interested in learning some more on Wind Energy, you might consider reading this book.
