Report Title NATURES POWER Brigit’s Garden · Report Title NATURES POWER ... Refrigeration and...

Report Sub Title: Natures Power Renewable Technologies Feasibility Study

Client: Brigit’s Garden

Date: 8th

June 2014

Prepared by: Alexandra Hamilton, Energy Engineer

PJ McLoughlin, Energy Analyst

Checked By: Paul Kenny, CEO

Report Title

NATURES POWER Brigit’s Garden

Brigits Garden Feasibility Report v40 of 21

CONTACT INFORMATION

Tipperary Energy Agency Ltd Craft Granary Church Street Cahir Co. Tipperary Contact person: Alexandra Hamilton, BA, BAI, MSc., MIEI, Energy Engineer, TEA Tel: 052 7443090 Fax: 052 7443012 e-mail: [email protected] Web: www.tea.ie

The Tipperary Energy Agency’s work for was co-funded as part of the Academy of Champions of Europe (ACE) Project which is funded by INTERREG North-West Europe (NWE).

About Academy for Energy Champions (ACE) ACE is an EU Interreg IVB funded project to support an enhanced level of innovation and competitiveness across northwest Europe by increasing the combined capabilities of sustainable energy champion organisations. www.aceforenergy.eu For more information please contact Catherine Wall, Marketing & Communications Coordinator at the Tipperary Energy Agency. E: [email protected] T: 052 7443090 or M: 086 3722760.


Table of Contents

1 EXECUTIVE SUMMARY ............................................................................................................................ 4

2 INTRODUCTION ........................................................................................................................................ 5 2.1 LOCATION ............................................................................................................................................ 5

3 BRIGIT’S GARDEN ENERGY CONSUMPTION ........................................................................................ 7 3.1 ELECTRICITY CONSUMPTION .................................................................................................................. 7 3.2 GAS CONSUMPTION .............................................................................................................................. 8

4 RENEWABLE TECHNOLOGIES ............................................................................................................. 11 4.1 SOLAR PV .......................................................................................................................................... 11 4.2 SOLAR THERMAL ................................................................................................................................ 12 4.3 BIOMASS BOILER (WOOD PELLET) ...................................................................................................... 14 4.4 AIR SOURCE HEAT PUMP (ASHP) ....................................................................................................... 17 4.5 SUMMARY .......................................................................................................................................... 19

5 CONCLUSIONS ........................................................................................................................................ 21


1 Executive Summary

Four renewable technologies have been examined for suitability and cost savings for Brigit’s Garden heating, hot water and electricity demand. It is recommended that solar PV panels be procured and installed, at a capital cost of ap-proximately €15,500 - €16,500 ex VAT. The PV panels will generate 9,000kWh of electricity a year, saving €1,575 per year (based on 17.5c/kWh day rate) It is recommended that a wood pellet biomass boiler be procured and installed on-site, at a capital cost of €8,500 - €9,500 ex VAT. The biomass boiler will generate 100% of the heat-ing & hot water demand, saving €1,864 per year. If the final costs for the wood pellet boiler are too high, the air source heat pump is an alter-native that is suitable for installation, and may be procured and installed if necessary. Prices may vary once detailed specifications are complete and the tender process is com-plete.


2 Introduction

Tipperary Energy Agency is working with Brigit’s Garden on the Nature’s Power project, funded by Science Foundation Ireland. Tipperary Energy Agency’s role is to size and specify a number of renewable energy technologies that can be installed at Brigit’s Garden. The initial funding application included

Solar PV

Solar Thermal

Air Source Heat Pump (ASHP)

The budget for the work package is €28,500. This is to include installation of the renewable technologies, plus an interactive element for each which can be used during the school and educational tours that occur at Brigit’s Garden.

2.1 Location

Brigit’s Garden is located near Rosscahill, County Galway, approximately 20km North West of Galway City. Brigit’s garden includes an 11 acre nature trail, educational facilities, office, visi-tor’s centre, gift shop and café. The building has a floor area of approximately 296m

2.

Figure 2.1: Site Location Map


Figure 2.2: Ariel View, Brigit’s Garden

Figure 2.3: Floor Plan of Brigit’s Garden building


3 Brigit’s Garden Energy Consumption

There are two fuel types currently used on site:

Electricity – MPRN 10010832921

LPG propane – current supplier; Calor Gas

3.1 Electricity consumption

Electricity bills for an 18-month period were provided. The annual consumption for 2013 was found to be 40,667kWh, at a cost of €5,480. The electricity split was estimated to be as shown in Figure 3.1. A number of assumptions were made, based on discussions and information provided by Brigit’s Garden:

Refrigeration and Washing and Dryer are based on client’s own calculations

Cooking (Electric) and extractor fan is based on 4 hours use for 100 days and on 2

hours use for 150 days

Lighting is based on 20W per m2 for internal lighting and assumed to have 15 feature

outside lighting estimated to be 200W each used for 4 hours for 100 days

Storage heating is estimated at 2kW and used for 2 hours per day for 100 days

IT is based on 4 PC/laptops used for 8 hours per day for 300 days

There remained a large amount of residual/unaccounted for electricity. Refrigeration was the largest electrical user, as there are 7 refrigeration units on site.

The units are split between day and night, as can be seen in Figure 3.2. There appeared to be a period during the summer where only night units were used, however it is assumed this was due to estimated meter readings, as the September 2013 bill included for a larger amount of day units than expected. This would take into account the missing units in June, July and August bills.

Figure 3.1: Electrical breakdown by appliance


Figure 3.2: Breakdown of Day & Night units 2013

Figure 3.3: Normalised Breakdown of Day & Night units 2013

3.2 Gas consumption

Bulk LPG is used on site for all heating and hot water needs, in addition to cooking. 2-years of bill data was provided. Annual LPG consumption is 3,010litres per year, which is equivalent to 21,337kWh/year. The cost per LPG per annum was €3,008.88. Using the following assumptions based on information provided by Brigit’s Garden, it was es-timated that cooking accounts for 21% of LPG consumption:

Use 3 burners for 3 hours and oven for 3 hours per day for Summer (100 days)

Use 2 burners for 2 hours and Oven for 2 hours for the rest of year (150 days)


Figure 3.4: Breakdown of LPG consumption between cooking, space and water heating

Therefore, 79% of LPG consumption is used for space and hot water heating. This was bro-ken down further to find the amount of LPG used to heat water on the premises, in order to estimate the size of solar thermal panels that will be required.

The hot water demand was calculated based on the number of people entering the facility. The number of people per day included staff and visitors, as provided by Brigit’s Garden. The litres per day are estimated; as a reference the average number of litres per day in a domes-tic setting is 40 litres, however showering would be included in this. Therefore a lower amount of 8 litres per day, per person was used. Other assumptions made were:

Temperature - 45°C

Operating Day per week – 6 days

People/day Litres/person Litres/day No. of Days Yearly Total

Summer 100 8 800 85 68,000

Autumn/Spring 60 8 480 85 40,800

Winter 24 8 192 170 32,640

340 141,440

Average yearly L/day 416

Table 3.1: Hot Water Demand


To calculate the amount of energy required for heating 416L/day to a temperature of 45

0Celsius, the following equation is used:

P = Mw x Cp, x Δt

Where P = Power (kW) = mass of water (kg) = specific heat capacity of water (4200 J/kg K)

= difference in temperature It is assumed that water in a tank maintains a temperature of 15

0C. Therefore the difference

in temperature to get to 450C is 30. This gives a daily power requirement of 52.416MJ, which

equates to an annual energy requirement of 4,950kWh/year. This is 29% of the overall heat-ing demand for the site. This leaves 71% of the LPG consumption used for space heating, which in this case is under-floor heating. This is a relatively small amount, equal to approximately 11,842kWh/year, which is less than an average domestic house and equates to 38 kWh/ m

2. This is quite low, and

reflects the low energy build of the new part of the building, the high internal heat gains from cooking and people using the facility.


4 Renewable Technologies

Four renewable technologies have been examined, based on Brigit’s Garden electricity and thermal demand. The computer programme RETScreen was used to size the technologies and calculate the estimated savings. Budget and planning restrictions were also taken into account during the analysis, to ensure size of technologies did not exceed the planning ex-emptions. The timescale of the project would not allow for planning were it required. Prices are estimated based on past experience and initial discussions with suppliers. It should be advised that prices may vary once tenders are sought for the final specification.

4.1 Solar PV

As discussed in Section 3.1, the annual electrical usage on site is 40,667kWh. A solar PV system was investigated for this site to help reduce the electrical demand from the grid. Photovoltaic panels are solar panels that convert solar radiation or energy into an electrical current. When sunlight is absorbed by a material known as a semiconductor, the energy from the sunlight is converted into electric energy. This property of the material is known as the photoelectric effect. Silicon is the most common semiconductor used by PV manufacturers.

Figure 4.1: Solar Map of Ireland


The potential for solar panels in Ireland has often been down played, with common myths stating that as there is no sun in Ireland, solar energy is not an effective way of producing en-ergy. However, the potential for solar energy in Ireland is very significant, as shown in the so-lar irradiation map. In fact, a 1m² surface area receives an average 900 to 1000kWh of solar energy per year, which is equivalent to the amount of energy in 100 litres of oil. The solar ir-radiation map of Ireland shows that Brigit’s Garden can benefit from approximately 900kWh/m2 of solar irradiation. The following assumptions were used during the calculations for sizing a PV system:

Annual inflation growth of 2%

Project lifetime of 20-years

Capacity Factor of Solar = 10%

The planning exemptions for PV, as per SI 235 of 2008, state that for a commercial property the size of PV panels should not exceed 50m

2. Due to the tight deadlines of this project, it

was decided that only systems below this threshold would be examined, to avoid the delay of applying for planning permission. Therefore a 7kW system has been examined. The area of a 7kW system will be approximately 45-49m

2. There is a limit of free standing panels of 25m

2,

so a combination of roof and ground mounted panels will be used. The capital costs of such a system will be in the region of €15,000 – 16,000, ex VAT

1. This in-

cludes installation and electrical connection to tie in to the existing electrical distribution board at Brigit’s Garden, and the installation of a new hot water cylinder, which is required. It is sug-gested that the system will be placed on the roof and ground, facing south in order to maxi-mise the solar irradiation. The 7kW system is estimated to produce 6,300kWh of energy, which is equal to 15% of the total electrical demand. In reality, as the electrical demand is higher in summer, and the sun should shine for longer during the summer months, it is estimated that most electricity will be generated and used on-site. Using an average unit price of 17.5c/kWh (from the day unit of bills provided by Brigit’s Gar-den), this equates to a saving of €1,100/year. This gives a simple payback of 13years (based on the estimated capital cost of €15,000). As energy prices have steadily increased by on av-erage of 8% per annum over the last 10 years, the likely payback will be in the region of 10-13 years.The TEA recommend in this case to utilise an immersion controller that will allow any excess PV generated energy that is not used on site to be converted to hot water. This will essentially act like a small solar thermal system and maximise the value of the PV generated electricity on site.

4.2 Solar Thermal

Solar hot water is also named solar thermal. This technology captures the energy from the sun to heat water, which is typically the hot water supply. Mostly solar panels are roof mounted facing south at an angle of 30 to 45 degrees to the hori-zontal. It is acceptable to mount solar panels on the ground using a frame; this has the benefit

1 TEA tendered two other 7kW systems (without domestic hot water tank) for €14,500 and €14,900 in 2014.


of allowing optimum tilt and azimuth. But the significant disadvantage that possibly the collec-tor will be located too far from the tank and significant heat could be lost (even through well insulated pipes).

Solar panels should be mounted to face south where possible, however a small variation in this angle is acceptable if the roof is not facing directly south, 15

o to either side may be ac-

ceptable. Two main types of solar thermal panel are available:

Flat Panel This type appears flat similar to a dark black coloured pane of glass. This type consists of a looped grid of pipes behind the dark glass, the pipes contain a heat transfer liquid, usually glycol, (similar to antifreeze). This liquid is heated up to very high temperatures (can be over 100

0C) while it is pumped through the solar panel pipes. The liquid is then pumped through a

sealed heat transfer loop within the insulated domestic hot water tank (the glycol never comes into direct contact with the water). This heats up the water in the hot water tank.

Evacuated Tube Evacuated tube solar collectors work by a similar principle to flat panels above, however, they are more efficient per unit area as they make greater use of low level sunlight and the tubular shape of the collectors ensures that an optimum angle on incidence is maintained to the sun’s rays for more of the day as the sun moves from east to west.

Figure 4.2: Flat Panels & Evacuated Tubes

The size of system used for the purposes of this analysis was a 6.34kW, 9m

2 system. How-

ever, this will increase the overall area of solar panels on the roof to over 50m2 if both sys-

tems are chosen. Therefore, the size of the PV system would need to be reduced to 6kW, or, if increased to cover more of the electrical load, planning will be required.

Evacuated tube systems are much more efficient in an Irish climate, therefore this was cho-sen above flat panels. As discussed above in Section 3.2, the following assumptions were made:

416 litres of water per day

35° tilt of panels

Orientation – Due south

Solar Water losses – 3%


Storage losses – 5%

Annual inflation rate growth – 2%

Project life – 20-years

The capital costs of such a system would be in the region of €10,000 ex VAT, including a new

hot water cylinder which is required. The solar panels should produce 3,750kWh, which is

equal to 76% of the hot water demand. Some LPG will still be required to heat the remainder

of the hot water, at a cost of approximately €242 per year.

As can be seen in Table 4.1, this equates to an annual saving of €563 on LPG costs. There-fore, the payback period for the solar thermal panels is in the region of 17.75-years (based on estimated capital costs of €10,000).

Heating system for hot water Unit 100% LPG costs Back-up LPG costs

Project verification Base case Proposed case

Fuel type Propane - L Propane - L

Seasonal efficiency 88% 88%

Fuel consumption - annual L 805.2 242.5

Fuel rate €/L 1.000 1.000

Fuel cost € 805 242

Annual € Savings € 563 Table 4.1: € Savings due to solar thermal panels

4.3 Biomass Boiler (Wood Pellet)

Wood pellets are made from wood shavings and sawdust and are used in highly efficient and convenient automatic wood boilers. Because they have a low moisture and ash content wood pellets burn very efficiently. What's more they are compact and easy to store. Typically pellets come in bags (ideal for stoves or smaller boiler systems) or are delivered in bulk by truck (ideal for boiler systems with bulk stores). Wood pellets can be ordered from local fuel mer-chants. Good quality wood pellets with a moisture content of 8% will have a calorific value of approximately 4,700 kWh/tonne.


Figure 4.3: Wood Pellet Boiler

Figure 4.3 shows a typical wood pellet boiler and an arguer feed silo storage. Fuel handling is convenient and requires a relatively small storage volume due to the high energy density of the pellets. Storage can be adjacent to the boiler itself or in separate fuel store. In both cases a feeding mechanism (screw / auger) is used to transport the pellets from the store to the boiler. Pellet boilers are generally lit automatically and continue to operate without manual in-tervention.

The following assumptions were used during the calculations:



Size of Boiler = 15kW

Tonnes of Pellet need per year = 3.5Tonnes

Number of operating days = 250/year Two options were considered; manual fuel feed and automatic fuel feed.

Manual Fuel Feed A pellet boiler with manual fuel feed is a slightly cheaper option, with capital costs around €6,500 - €7,500. This includes installation and hot water cylinder. Fuel will be supplied in bagged pellets, and the pellets will need fed into the boiler manually. Delivery of the pellets will depend of storage capacity at Brigit’s Garden. It is thought that 10kg bags would be most manageable for staff at Brigit’s Garden. Cost of 100 bags (1 Tonne) is approximately €330. An average of 14kg of pellet will be required to run the boiler; therefore the boiler will require 1.4 bags per day. The boiler will hold 100kg, therefore it is es-timated that a staff member would require topping up the boiler once a week to ensure that there is enough pellet to fuel the boiler continuously. Alternatively, one bag every 1-2 days could be topped up to spread the work load and to ensure the boiler does not run out of pellet.


Similarly, the ash tray in the boiler will require emptying – this can be done at the same time as filling the boiler with fuel. An annual service will be required, similar to an oil or gas boiler. The operating days of the boiler is 250-days, which equates to an annual consumption of 3.5 tonnes of wood pellet. A new biomass boiler will have an annual seasonal efficiency of over 90%, compared to the current LPG boiler, which is estimated is operating at an efficiency of 88%, which is relatively high based on the fact it is a condensing boiler. The biomass boiler is sized to produce 100% of the heating and hot water demand. As can be seen in Table 4.2, this equates to an annual saving of €1,654, giving a payback time of 4.2-years (based on estimated capital cost of €7,000).

Heating system

Technology Gas Biomass system

Heating delivered kWh 16,792 16,792 100.0%

Fuel type Propane Biomass

Seasonal efficiency % 88% 90%

Fuel consumption - annual Litres 2,809 3.5 Tonnes

Fuel rate €/L 1.00 330 €/T

TOTAL Annual Fuel cost € 2,809 1,155 €

Annual € savings € 1,654 Table 4.2: € Savings due to manual feed biomass boiler

Automatic Fuel Feed - With Pellet Storage For this option, a pellet boiler supply automatically by arguer system, shown in the previous picture, is explored. While the capital cost for this is higher than the manual feed, the running costs are lower and the deliveries are in bulk, approximately €270/t for bulk versus €330/t for bagged (prices taken from SEAI fuel cost comparison data). The capital costs of this type of boiler & associated equipment is in the region of €8,500 – €9,500 ex VAT. This includes the buffer storage, auger, silo storage unit and installation. This is approximately 32% higher than the manual feed option described above. The benefits in-clude a reduction in manual operating requirements and the savings in fuel costs due to bulk deliveries.

Heating system

Technology Gas Biomass system


Fuel type Propane - L Biomass


Fuel consumption - annual L 2,809 3.5 t

Fuel rate €/L 1.00 270 €/t

TOTAL Annual Fuel cost € 2,809 945 €

Annual € savings € 1,864 Table 4.3: € Savings due to automatic feed biomass boiler


As can be seen in Table 4.3, this biomass boiler system will produce annual savings of €1,864, giving a payback time of 4.8-years (based on estimated capital costs of €9,000). As the capital costs are covered by the funding it might be best to take advantage of the economies of scale and put a storage system in place, as it will save €210/year.

Note: The installation of the fuel stores is very important, guarantees should be put in place by installers of these systems as those should be sought before installation. There are many options for storage available and TEA will endeavour to get the most suitable option to suit the available budget. The above prices for biomass systems do not include the storage shed due to the number of options available.

4.4 Air Source Heat Pump (ASHP)

An air source heat pump (ASHP) is a system which transfers heat from the air outside to in-side a building, or vice versa. Under the principles of vapour compression refrigeration, an ASHP uses a refrigerant system involving a compressor and a condenser to absorb heat at one place and release it at another. Heating and cooling is accomplished by pumping a refrigerant through the heat pump's indoor and outdoor coils. Like in a refrigerator, a compressor, condenser, expansion valve and evaporator are used to change states of the refrigerant between colder liquid and hotter gas states.

The coefficient of performance (COP) of an ASHP gives a ratio of electrical consumption ver-sus thermal output. Average COP should be in the region of 3 or 4, meaning that for every 1 unit of electricity consumed, 3 or 4 units of heat are produced, which is where the savings are produced.

The following assumptions were used during the calculations:



Size of ASHP = 15kW (thermal output, based on 4-6kW electric input)

http://en.wikipedia.org/wiki/Heat_pump

http://en.wikipedia.org/wiki/Vapor_compression_refrigeration

http://en.wikipedia.org/wiki/Refrigerant

http://en.wikipedia.org/wiki/Refrigerant

http://en.wikipedia.org/wiki/Gas_compressor

http://en.wikipedia.org/wiki/Condenser_(heat_transfer)

http://en.wikipedia.org/wiki/Expansion_valve_(steam_engine)

http://en.wikipedia.org/wiki/Evaporator

http://en.wikipedia.org/wiki/Liquid

http://en.wikipedia.org/wiki/Gas


The ASHP was sized to produce 100% of the heating and hot water demand, however, an air source heat pump will be able to heat hot water up to a certain temperature. For addi-tional temperatures that may be required in a commercial kitchen, back up immersion may be required. The capital cost of this size of ASHP is in the region of €8,000 - €9,000 ex VAT, including a new hot water cylinder, which will be required. The seasonal coefficient of performance of 3.5 is equivalent to an efficiency of 350%. This would be a conservative COP for under-floor heating system, similar to the existing heating system in Brigit’s Garden. The temperature difference required for under-floor heating is lower than for high temperature radiator heat-ing systems, and therefore works in conjunction with an ASHP. A COP for under-floor heat-ing is generally in the region of 3.2 – 3.8, and therefore an average of 3.5 is used for these calculations. It is assumed that 70% of the heating will be done at night at the night rate for electricity (currently 0.0879c/kWh), with 30% occurring at the day rate (currently 0.1745c/kWh). There-fore the average unit price used for the calculations is €0.114/kWh. The hot water can be heated by the ASHP up to a certain temperature. It is suggested that the remainder be heated by an immersion to top-up the water to the required temperature for use in the kitchen & toilet sinks. It is estimated that an additional 1000kWh may be re-quired to heat the hot water to higher temperature, during the day using the day rate for electricity. As there may be a portion of the PV that is used for heating a figure of 1000kWh/ annum is assumed. It can be seen in Table 4.4 that the annual savings due to the ASHP are approximately €1,933, which will give a payback of 4.4-years (based on estimated €8,500 capital cost).

Heating system

Technology Propane ASHP


Fuel type Propane Electricity


Fuel consumption - annual Litres 2,809 4,623 kWh

Fuel rate €/L 1.000 0.114 €/kWh

Fuel Cost € 2,809 527 €

Fuel for additional hot water 2,000 kWh

Cost for additional hot water 0.1745 €/kWh

Fuel cost 174 €

TOTAL Annual Fuel Cost € 2,809 702 €

Annual € Savings € 2107 Table 4.4: € savings due to ASHP


4.5 Summary

Technology Energy Demand

(kWh)

Annual Savings (kWh)

Annual savings

(€)

Capital Cost (€)

Simple Payback (years)

Percentage of demand met by technology (%)

PV 0 6,300 1,100 15,500 – 16,500

13 15% of electricity

Solar Thermal 0 3,750 563 10,000 17.75 76% hot water

Biomass Boiler (manual feed)

16,792 0 1,654 6,500 - 7,500

4.2 100% heating & hot water demand

Biomass Boiler (auger feed)

16,792 0 1,864 8,500 – 9,500

4.8 100% heating & hot water demand

ASHP (& immer-sion top-up)

6,625 10,167 2170 8,000 – 9,000

4.1 88% heating & hot water

Photovoltaic Panels (PV)

The PV panels will produce 15% of electrical demands, equivalent to 9,000kWh per year

This equates to annual savings to Brigit’s Garden of €1,100 per year on electricity bills, based on current day rate of 17.5c/kWh

The PV will take up approximately 45m2 of roof space, which falls under the maxi-

mum permitted 50m2

As these are the only electricity generating renewable technology examined, The TEA recommends that PV panels be installed on the roof of the visitors centre

The Costs should include an immersun or equivalent immersion controller that will dump the residual generated PV energy into the domestic hot water tank. This is will ensure that every kWh of PV generated electricity is utilised and that the need for any top up heat required is minimised.

Solar Thermal Panels

Solar Thermal panels will only produce 76% of the annual hot water demand, equiva-lent to 3,750kWh, or 22% of total thermal demand

The annual savings are the lowest of all the technologies at €563/year

It is suggested that the roof space be better utilised by installation of PV panels, therefore it is not recommended to install solar thermal panels at Brigit’s Garden


Biomass Boiler

Although the manual feed biomass boiler is cheaper to install, there is a significant onus on the staff to ensure that fuel is fed into the boiler on a regular basis

Running costs of the automatic feed is lower due to the ability to buy in bulk

The ethos and available meadow space of Brigit’s Garden lends itself well to the in-teractive element of the biomass boiler. It has been discussed that trees can be planted on site to show the entire life cycle of the fuel. Although the trees planted will not be the exact trees used for the fuel of the wood pellet boiler, the trees planted can be used for other purposes (sold to a supplier in the area should be investigated)

As 100% of heating & hot water can be produced by renewable sources, it is recom-mended that an automatic feed biomass boiler be installed, to reduce operational demand and create greater cost savings on bulk fuel deliveries

Air Source Heat Pump (ASHP)

The ASHP will produce 88% of the heating & hot water demand – an immersion may be required to top up the hot water to the required temperature

If a COP of 3.5 can be reached, a total of 10,167kWh per year could be saved on thermal demand

This equates to an annual saving of €2100

The interactive element is not as good as the biomass boiler. Although both systems are suitable for installation at Brigit’s Garden, the biomass boiler is recommended above the ASHP

However, depending on final costs that come in for the wood pellet boiler & storage unit, the ASHP may be looked at if prices are not in line with the allocated budget


5 Conclusions

Four renewable technologies have been examined for suitability and cost savings for Brigit’s Garden heating, hot water and electricity demand. It is recommended that solar PV panels be procured and installed, at a capital cost of ap-proximately €15,500 - €16,500 ex VAT. The PV panels will generate 6,300kWh of electricity a year, saving €1,100 per year (based on 17.5c/kWh day rate) It is recommended that a wood pellet biomass boiler be procured and installed on-site, at a capital cost of €8,500 - €9,500 ex VAT. The biomass boiler will generate 100% of the heat-ing & hot water demand, saving €1,864 per year. If the final costs for the wood pellet boiler are too high, the air source heat pump is an alter-native that is suitable for installation, and may be procured and installed if necessary. Prices may vary once detailed specifications are complete and the tender process is com-plete.

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