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General Renewable Topics => General Discussion => Topic started by: Matthew101 on April 24, 2019, 08:10:55 PM



Title: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 24, 2019, 08:10:55 PM
Hello everyone,

I am currently a final year student doing my dissertation on a hybrid renewable energy system design and evaluation in the UK, would appreciate if you guys could give me some feedback on issues I am currently having. Firstly the system I want to install is a 2.5kw wind turbine with a 3kw pv system connected to the grid (to meet my annual load). I am wondering what would a system spec look like for this? how many inverters would I need? if anyone could give me some starting points It would be appreciated as I am struggling as to where to start.

Many Thanks
Matthew.


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Ted on April 25, 2019, 09:31:47 AM
Hi Matthew, and welcome to the Forum.

It sounds like you would have two essentially separate systems, one for the turbine and one for the PV, so each would have its own inverter.

There are initial issues with assessing the suitability of your location, sorting planning permission/permitted development, getting DNO approval for going above 3.68kW export capacity, and so on.

Is this a real system you hope to install, or just hypothetical to write up for your dissertation?


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 25, 2019, 10:11:07 AM
Hi Ted

Really appreciate the reply! No the system will just be a write up, would you be able to give me more information of what way the system would be set up?


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: djs63 on April 25, 2019, 10:40:40 AM
Hi, need to know where the electricity is going eg. Space Heating, hot water, electric car, battery...
We set up a system 10 years ago when half these loads were not around, nor were “diverters” like Immersun and others. We are grid tied, have space and water heating  and recently have EV.


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Ted on April 25, 2019, 10:58:05 AM
As I say you are really looking at two separate systems, one for each prime generator.

Have a look at our PV FAQ https://www.navitron.org.uk/forum/index.php/topic,19989.0.html especially section 5 on estimating generation.

You will also need to understand how to meet the G83/G59/G98/G99/G100 requirements http://www.energynetworks.org/electricity/engineering/distributed-generation/distributed-generation.html

Find out which company is the DNO for where you live https://www.ovoenergy.com/guides/energy-guides/dno.html then their website will have more details about grid connections.

Specific installation design criteria will be covered by MCS product and installer standards - https://www.microgenerationcertification.org/mcs-standards/

What exactly is 'hybrid' about what you are wanting to achieve? Do you want to utilise battery storage, for example?

Can I ask what degree you are pursuing?


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 25, 2019, 11:18:01 AM
Hi,

The electricity will be used just to meet the homes electric demands. The hybrid element of the design is just to use more than one means of a renewable energy source, I have thought about battery storage, is it effective to be tied to the grid as well as having battery storage? The demand of the house is 4.5kW


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Ted on April 25, 2019, 12:55:15 PM
A home's electricity demand will vary across the 24 hours of a day and seasonally across the year as well, as appliances/lighting are turned on and off.  There will be a demand profile that you would need to first study and understand. Without any local storage you are unlikely to match generation with demand at all well or are you planning to provide a notional balance by utilising export/import to/from the grid?

Is the 4.5 kW the maximum instantaneous demand or do you perhaps mean you need to generate 4.5 kWh per day?


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 25, 2019, 01:55:01 PM
I was planning on using the export / import tariff however thinking about it I think I should use a battery as well as I was thinking it would increase the payback time to much to justify it. I have attached a photo of the case study I made for this project and what it's current use it from the grid I hope this will give you a better understanding. And I'm currently studying architectural engineering!


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 25, 2019, 02:01:14 PM

(https://i.postimg.cc/wtGbmBzT/Img-190425141353337-1.jpg) (https://postimg.cc/wtGbmBzT)


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Ted on April 25, 2019, 02:54:28 PM
Ah OK, your annual demand is 4.5 MWh. Getting the right units/terminology is pretty important.

You need to model the typical generation for the size of PV and wind turbine you are thinking off across the 12 months as well, to see how the likely generation will map to your demand.  See the link in the PV FAQ page for PVGIS - which will give you a monthly breakdown for your chosen location. Example below.

Have a look here http://www.wind-power-program.com/UK_wind_speed_database.htm for some ideas on wind speed resources.


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 25, 2019, 04:30:39 PM
Hi,

Thank you for this information I am finding this very beneficial, would you have a generic method of calculating wind? And for the system set up from what you have said it would look something like this?
 
Solar generation (3kw)                     Wind (2.5kw)

Inverter (3kw)                            Inverter 2.5 (kw)

                  Battery (size to meet the load generated from both renewable sources)
                   House demands
                   Grid connection

From what I have researched and you have recommended would this be correct?


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Ted on April 25, 2019, 04:55:35 PM
3kW wind turbines are rather thin on the ground. The Britwind R9000 5kW http://www.britwind.co.uk/our-windmills/the-r9000 has some general data showing annual generation against various mean wind speeds.

There are various options for configuring a grid/battery system. Check the OFGEM guidance doc for the main alternatives - https://www.ofgem.gov.uk/system/files/docs/2018/12/storage_guidance_final_v2.pdf See chapter 3 for the different scenarios. Although note that the FITs scheme is no longer open to new applications.

Generally for PV systems the inverter is sized around 80% of the total panel size so as to minimise losses - see the previous link to MCS for detailed docs on this.


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 25, 2019, 07:58:06 PM
Hi,

I have used the information you have provided and now I am putting together an economic analysis of the system however I am not quite sure on how to work out the payback period, so far I have calculated;

Electricity from solar PV can only be produce when the sun is out so in the UK this is generally 6am – 6pm. The profile of the case study provides that the occupants aren’t home Monday – Friday therefore the electricity being produce when the occupants aren’t using it will be sold back to the grid through Feed In Tariff scheme (FIT) for 5.24p/kwh as seen In fig 5.1.1. When the occupants are home they will mostly being using electricity from the grid this is then bought for 17.66p/kwh. Money is also generated for generating power from a renewable energy source thus getting 3.79p/kwh.

Based on the case studied previously stated in the literature review we know that a Solar PV Case study 1 (4Kw) – Evo Energy Nottinghamshire was £3900 to installed therefore a 3kW system can be calculated by;
3900 / 4 x 3 = £2925
Therefore the total cost of installation was £2925. There are currently no incentives

Payback Period =  (Total cost of installtion+Grants)/(Anuual Savings+FIT+Generation Of PV)

As explained above most of the unused generated electricity from PV is sold back to the grid for 5.4p through FIT. 42% of the generated in a domestic setting is will be used on site however remainder 58% will be sold back to the grid.
Sold to grid / Used in building
Total output of installation = 2590kwh
Sold back to grid (58%) of 2590 = 1502kwh
Sold back at 5.4p = £81

Generation = 2590 x 3.79 = £98.16      

Used in building (42%) of 2590 = 1243.2kwh
Savings from grid = 1243.2 x 17.66p = £219.5

Annual Savings =
£81 + £98.16 + £219.5 = £398.66
Payback = £2925 / 398.66 =
Payback = 7.3 years

For research purposes I have included FIT, Sorry if this was a bit long I hope you can understand it! My issue now is working out the wind payback as I am unsure how to break it down, if you could provide any assistance it would be much appreciated! i have calculated the wind pv to produce 3459kwh!


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: andrewellis on April 26, 2019, 07:59:09 AM
The FIT ceased at the end of March. There is no 3.7p per kWh. At present there is no mechanism for being paid for export from new pv though the government is looking into a way for electricity providers to bid for your export on I think a half hourly basis.


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Ted on April 26, 2019, 10:05:07 AM
3900 / 4 x 3 = £2925
Therefore the total cost of installation was £2925. There are currently no incentives

Payback Period =  (Total cost of installtion+Grants)/(Anuual Savings+FIT+Generation Of PV)

As explained above most of the unused generated electricity from PV is sold back to the grid for 5.4p through FIT. 42% of the generated in a domestic setting is will be used on site however remainder 58% will be sold back to the grid.
Sold to grid / Used in building
Total output of installation = 2590kwh
Sold back to grid (58%) of 2590 = 1502kwh
Sold back at 5.4p = £81

Generation = 2590 x 3.79 = £98.16     

Used in building (42%) of 2590 = 1243.2kwh
Savings from grid = 1243.2 x 17.66p = £219.5

Annual Savings =
£81 + £98.16 + £219.5 = £398.66
Payback = £2925 / 398.66 =
Payback = 7.3 years

1:
3900 / 4 x 3 = £2925
This is too simplistic a view of the costs. The 3kW install will merely save 1kW of panels compared to a 4kW installation which is only a part of the total cost. Labour cost, for example, would likely be the same. The cost of the 3kW system compared to an indentical 4kW one might be a saving of around £500.

2:
Payback Period =  (Total cost of installtion+Grants)/(Anuual Savings+FIT+Generation Of PV)

This should be:

Payback Period =  (Total cost of installation-Grants)/(Annual Import Savings+FIT Export+FIT Generation)

As you say there are no grants in any case. If there were then, under the FIT rules, the system would probably be ineligible as a domestic system for FITs.

3:
As explained above most of the unused generated electricity from PV is sold back to the grid for 5.4p through FIT. 42% of the generated in a domestic setting is will be used on site however remainder 58% will be sold back to the grid.

Under (the now closed) FITs the export would be deemed at 50% without separate export metering, so being paid for the notional 58% here is wrong.

The notional balance of 42% used in the home sounds too high if nobody is home during the day all week.



Title: Re: Dissertation Research on hybrid solar-wind system
Post by: pdf27 on April 26, 2019, 12:49:44 PM
What subject is the dissertation on? The modelling done so far sounds very simplistic compared to what I would have expected.

One thing which would be potentially very interesting for modelling payback is to look at real-life data for historic PV output - this is available to download from https://www.solar.sheffield.ac.uk/pvlive/ and if you have a model for domestic energy use in 15 minute increments you could match these up to see whether energy is likely to be consumed locally or exported. Once you've done that it's straightforward to introduce a model for a battery, Smart Grid Ready heat pump, etc.

In the same way wind power data for the whole of the UK is available to download - quite a few sites have it, I tend to use http://www.gridwatch.templar.co.uk . More care needs to be taken here to work out capacity factors since unlike PVLive the total installed wind fleet isn't listed in the same data set, but it should be possible. That will then essentially give you a power curve for a notional "national average" wind turbine, which you can then adjust for a domestic one which I suspect will tend to have higher cut in/cut out speeds.

The other thing to watch out for is maintenance costs, cost of capital, etc. - PV is pretty much maintenance free unless an inverter dies, but the same is emphatically not true for wind as you need to keep an eye on bearings, etc. Any financial calculations should really include this too.


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: heatherhopper on April 26, 2019, 02:46:45 PM
Interesting consumption profile for the UK Matthew. Apparent PV payback will benefit nicely  whistle


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 28, 2019, 07:06:23 PM
Hi,

Thanks again for the help, when calculating the demand for the house it is 4500kwh however my output for the renewable energy system 6000kwh should my system be this big or is it okay because it will be sold back to the grid? Should I change the size of my system?


Title: Re: Dissertation Research on hybrid solar-wind system
Post by: billi on April 29, 2019, 08:28:57 AM
Hello
well , there is a lot to be said about how the units are used in parallel to production , and storage into batteries and  heat  is a add on to  flexibility and  increases  self consumption and independence from the grid 

there has been a study made  at a Berlin University   maybe  that is some help , bad  translation  here


 https://translate.google.com/translate?sl=auto&tl=en&u=https%3A%2F%2Fwww.volker-quaschning.de%2Fartikel%2F2012-10-solare-unabhaengigkeit%2Findex.php


I can assist for better understanding ,  if you like

Billi



Title: Re: Dissertation Research on hybrid solar-wind system
Post by: Matthew101 on April 30, 2019, 09:52:01 PM
Hi,

When working out the inverter size for wind would it be sized for example a 1kw turbine to a 1kw inverter? or would it be sized to roughly 80% like solar?