3 Results

3.1 Industry Profile

There are no official statistics for the total area of heated greenhouses in New Zealand.

The estimates of industry size in the most recent comprehensive horticultural survey by the Department of Statistics for the year ending June 2000 is for greenhouse cropping area. There is no distinction made between heated and unheated greenhouses.

In the absence of more accurate figures it has been assumed that all greenhouse vegetable crops are heated. No attempt has been made to estimate the size of the heated nursery or flower industry although the areas would be relatively small compared to the total size of the respective industries.

There are approximately 250 ha of heated greenhouse vegetable production in New Zealand, 200 ha in the North Island and 50 ha in the South Island.

There are a wide range of greenhouse types including glass, single and twin skin plastic. The type of structure and their age has a large influence on the thermal characteristics. No information is available on the area covered by each greenhouse type. The more thermally efficient twin skin plastic houses have lower light levels, than glass, particularly as the plastic ages, which can reduce yields.

Table 2 shows the regional distribution of greenhouse crops. Of the total area in greenhouse vegetable crops, 79 percent are grown in the North Island, and approximately 68 percent are grown in the Auckland region alone.

In the South Island 50 percent of the vegetable production comes from the Canterbury region which represents 10 percent of the New Zealand crop.

Throughout New Zealand, tomato production accounts for 64 percent of the vegetable crop, with cucumbers and capsicums representing 20 percent and 16 percent respectively. Other minor crops such as aubergines were not included in the statistics.

The distribution of greenhouse tomato production area is:

Auckland 56%
Canterbury 12%
Waikato 7%
Tasman 5%
Northland 4%

The remaining 16 percent is scattered around New Zealand.

Flower production has the same greenhouse area as vegetables, 250 ha, however while most of the vegetable production is heated only a small proportion of flower growers use heat. Those flower growers that do heat, for example many rose growers, use similar heating regimes to vegetable producers.

The greenhouse nursery industry at approximately 100 ha in total, would only have a small fraction of growers that use heating.

Table 2. Area in Indoor Crops Harvested by Regional Council

During the Year Ended 30 June 2000

Regional Council	Tomatoes	Capsicum	Cucumber	Nursery Crops	Flowers	Mushrooms
Square Meters

Northland Region	62,607	C	57,944	38,246	304,445	C
Auckland Region	893,241	C	246,132	455,338	1,034,878	C
Waikato Region	111,579	26,273	C	17,154	310,132	C
Bay of Plenty Region	28,729	26,931	C	35,858	C	C
Gisborne Region	C	C	C	33,596	C	0
Hawke's Bay Region	36,035	8,196	C	57,290	39,353	C
Taranaki Region	C	C	15,616	8,892	78,558	0
Manawatu-Wanganui Region	29,816	4,381	C	49,267	185,383	C
Wellington Region	28,489	C	5,484	37,781	23,042	C
Total North Island	1,205,928	365,296	421,902	733,420	2,178,472	216,257

Tasman Region	86,061	14,065	14,098	40,082	30,522	0
Nelson Region	31,732	C	C	C	C	0
Marlborough Region	61,231	2,640	C	4,170	25,649	C
Canterbury Region	189,957	C	51,399	125,445	205,194	C
Otago Region	13,214	C	C	71,246	28,016	C
Southland Region	C	C	C	18,370	5,527	0
Total South Island	396,020	49,252	77,132	259,413	306,254	190,130
Total New Zealand	1,601,948	414,548	499,034	992,833	2,484,726	406,387

Source: Department of Statistics Horticultural Production Survey for the year ending June 2000

C - Data suppressed for confidentiality reasons.

Table 3. Number of Indoor Vegetable Growers by Regional Council

During 2002

Regional Council	Tomatoes	Capsicum	Cucumber

Northland Region	29	16	18
Auckland Region	237	31	53
Waikato Region	15	3	2
Bay of Plenty Region	18	5	4
Gisborne Region	7	0	0
Hawke's Bay Region	29	8	4
Taranaki Region	3	1	4
Manawatu - Wanganui Region	12	3	3
Wellington Region	40	6	8
Total North Island

Tasman Region	-	-	-
Nelson Region	35	6	13
Marlborough Region	8	2	5
Canterbury Region	62	13	14
Otago Region	15	3	4
Southland Region	7	0	2
Total South Island
Total New Zealand	517	97	134

Source: Vegfed

Table 3 gives the distribution of growers, although they can be counted more than once if they grow a couple of different crops. The industry trend is for the number of operations to reduce and the average size to increase. While it is not possible to accurately gauge the recent change in productive area it is the opinion of Vegfed (pers. comm. Tony Ivicevich) that the productive area has remained relatively constant and that this is likely to remain the same in the foreseeable future unless a significant and consistent export market is found. Significant areas that have been constructed recently have been offset by smaller growers exiting the industry.

3.2 Grower Sample Profile

The survey was biased towards coal users which made up nine of the twelve surveyed. Two of the nine coal users also used gas and a further two used gas exclusively. One grower used waste oil for heating. Seven of the growers were in South Auckland or further north, one was in Tasman and four were in Canterbury or Otago.

3.3 Production Profile

Table 4. Production per Operation

Indicator	Average Surveyed	Range	NZ Average*
Vegetable production area (m2)	34,700	2,700 – 201,000	3,400
Tomato production area (m2)	9,400**	2,800 – 32,000**	3,100
Tomato yield (kg/m2)	43	30 - 50	42

* Some double counting of growers makes these figures lower than the true value.

** Those growing two or more crops were excluded as the survey did not ask for the specific area of each crop.

3.4 Energy Profile

3.4.1 Grower Operation Level

The annual total energy input (excluding solar) into a greenhouse system can either be expressed as energy intensity in MJ/m2 or by incorporating the operation’s productive output it can be expressed as energy input in MJ/kg output.

The average energy indicators for the surveyed operations are shown in Table 5. This is not representative of the industry as the pilot survey was very small and growers were selected on the basis of obtaining a range of different greenhouse types, fuel sources and regional locations.

Table 5. Energy Indicators

Indicator	Average	Range
Total Energy Intensity (MJ/m2)	1,600	700 – 2,600
Energy Input (MJ/kg tomato)	38	16 – 51

Table 6. Energy Intensity by Region and Greenhouse Type

Region	Glass (MJ/m2)	Double Plastic (MJ/m2)
North Island	1,600	700*
South Island	2,100*	1,600*

* Two or less growers in this category

Some of the variation shown in the energy indicators can be explained by the type of greenhouse and its regional location. Table 6 gives an indication of the difference both between the North and South Island and glass versus double skin plastic. Due to the extremely small sample size these figures need to be viewed with some caution. However they do show what you would expect, namely that South Island production is more energy intensive than in the North Island and that glass cladding is more energy intensive than double skin plastic.

3.4.2 National Level

Extrapolating the results from this pilot survey to estimate the total energy size of the greenhouse industry must be viewed with caution as the survey was not representative, see Methodology Section 2.0. Not only was the survey not representative but there is uncertainty about the heated area, as well as greenhouse cladding type of heated greenhouses.

Assuming an estimated heated greenhouse area of 250 ha the national energy use for greenhouse vegetable production is between 2 and 7 PJ. As a best estimate the likely national energy use figure will be between 2 and 4 PJ.

It is possible to calculate the national energy use for the tomato sector based on production. The annual production of standard loose round tomatoes is approx 35,000 tonnes (per. comm. Ken Robertson, Vegfed) as a result the energy input will range between 0.6 to 1.8 PJ, with an average of 1.3 PJ. It is necessary to add to this the energy input from the unknown quantity of specialty tomatoes; e.g. cherry tomatoes, small and medium plum tomatoes, tomatoes on the vine plus the other greenhouse vegetables including cucumbers and capsicums which represent approximately 36 percent of the industry by size.

The national energy demand for the ‘agriculture and hunting’ sector is 12.1 PJ (Energy Data File Jan. 2002). This figure underestimates the actual use as it does not include gas which is unallocated for the different agricultural and industrial sectors.

However, if it is assumed that 12.1 PJ represents the national energy demand for agriculture and hunting, 2 PJ represents 17 percent of the national agricultural energy demand.

3.5 Carbon Profile

3.5.1 Grower Operation Level

Gross carbon dioxide emissions of the surveyed operations averaged 125 kgCO2/m2. On the tomato operations the average gross carbon emissions were 3.1 kgCO2/kg tomato. Like the energy indicators, the carbon indicators have a large range reflecting the type of greenhouses and their regional location.

Table 7. Carbon Indicators

Indicator	Average	Range
Gross CO2 Emissions (kgCO2/m2)	125	35 – 235
Gross CO2 Emissions (kgCO2/kg tomato)	3.1	0.8 – 4.7

Table 8. Carbon Emissions and Tax (Surveyed Operations)

	Average	Range
Annual Tonnes CO2 per operation	3,500	130 – 21,800
Annual Carbon Tax ($/m2)	3.10	0.80 – 5.90
Annual Carbon Tax per operation ($)	88,400	3,400 – 544,000

Table 9. Carbon Emissions and Tax (NZ’s average sized operation)

	Average	Range
NZ’s Average Size Operation (m2)	3,400
Annual Tonnes CO2 per operation	420	110 – 800
Annual Carbon Tax per operation ($)	10,500	2,900 – 19,900

3.5.2 National Level

On a national basis the gross carbon dioxide emissions from the greenhouse vegetable industry range between 90 and 590 ktCO2 with a mean of 310 ktCO2. These figures are likely to over estimate the true national figure because of the survey bias towards coal users. The uncertainty over the industry’s size and type of greenhouses adds further potential error to the estimate of gross emissions. Even at the low end of the range a carbon tax will add another $2.25 million dollars worth of costs to the industry. Ninety ktCO2 is 7 percent of the agricultural sector’s carbon dioxide emissions in 2001 (NZ Greenhouse Gas Emissions 1990 – 2001).

See Section 3.4.2 for a discussion on the accuracy of extrapolating these figures.

3.5.3 Net Carbon Emissions

Under the Kyoto Protocol New Zealand has to reduce its emissions to 1990 levels or take responsibility for any excess emissions. New Zealand's assigned amount is 365 million tonnes of carbon dioxide equivalent for the first commitment period. Carbon sink credits will help the Government achieve that goal. Afforestation is counted as a carbon credit because carbon sequestered in forests is considered "permanent" under the protocol, but carbon tied up in other crops for example, tomatoes and tomato plants, would not be counted as a credit under Kyoto because it is released within a year of being sequestered. Net emissions from the greenhouse sector (or any other non-forestry sector) are not therefore relevant in meeting the requirements of the Kyoto protocol.

3.5.4 Carbon Tax

Table 10 shows the effect of a carbon tax, at a rate of $25/tCO2 on each fuel source considered in this study. Sub-bituminous coal has a carbon tax of 4.8 cents per kilogram or $48 per tonne.

Table 10. Carbon Tax by Fuel Type

Fuel	Units	C O2 (kg/unit)	Carbon Tax (¢/unit)
Coal (sub-bituminous)	kg	1.92	4.81
Waste oil	l	2.85	7.13
Gas	kWh	0.19	0.47
Electricity	kWh	0.16	0.39

Table 11. Energy Intensity, Carbon Emissions and Tax by Fuel Type

Description	Energy Intensity (MJ/m2)	Carbon Emissions (kgCO2/m2)	Carbon Tax ($/m2)
North Island Glass and Coal grower 1	1,200	110	2.70
North Island Glass and Gas grower 1	2,100	110	2.70
North Island Glass and Coal grower 2	1,400	130	3.10
North Island Glass and Gas grower 3	1,400	80	1.90

Table 11 illustrates that given the same energy intensity a coal fired operation can expect to pay approximately 60 percent more carbon tax than a gas fired user. As a consequence of the survey being biased towards coal users the average carbon tax of $3.10/m2 is probably an over estimate for the industry. Although it must also be remembered that one grower in the survey would pay a carbon tax of $5.90/m2.

3.6 Coal Type

Both the energy value and carbon content of coal varies considerably depending on the type of coal. There are three main coal types lignite, sub-bituminous, and bituminous. Even within these coal types there are variations depending on the region and mine. Assuming average figures for each coal type (MED, 2002) the effect on the carbon tax can be seen in Table 12.

Table 12. Carbon Content and Tax by Coal Type

Coal Types	Energy (MJ/kg)	Carbon Content (gC/MJ)	CO2 (kgCO2/MJ)	CO2 (kgCO2/ kgcoal)	Carbon Tax (¢/kg)	Carbon Tax ($/t)	Carbon Tax (¢/MJ)
Lignite	14.1	27.6 a	0.101	1.43	3.57	35.67	0.25
Sub-bituminous	21.1	26.2 b	0.091	1.92	4.81	48.11	0.23
Bituminous	28.6	25.8 a	0.095	2.71	6.76	67.64	0.24

Data source:
a IPCC, 1996
b NZ Greenhouse Gas Emissions 1990-2001

Despite bituminous coal being almost double the tax cost per tonne compared to lignite coal, the higher energy content of bituminous coal means that on an energy content basis the carbon tax cost is very similar.

In the pilot survey the growers using coal for heating were asked for the annual quantity in tonnes. The survey did not ask what type of coal they were burning. To calculate total energy use for each operation, the assumption was made that the coal was sub-bituminous. Where this was not the case the total energy input in the system will be over or under estimated as shown in Table 12. As a consequence the carbon content will also be over or under estimated. Any follow up work needs to determine the coal types that are being used.

3.7 Expenditure

Operating costs average $47/m2 and ranged between $33/m2 and $86/m2. The list of inputs that made up the operating costs is shown in the survey form, Appendix 1.

Grading/packing/marketing was collected but not included in the total operating costs above. This follows the model used in the analysis of "on-farm" energy inputs in a dairy farm (Wells, 2001), in which Fonterra’s costs of manufacture, packaging and marketing were not included. Repairs and maintenance was also excluded as they were considered a component of fixed costs. Diesel, petrol and lubricants while being an operating cost were also removed in order to be consistent with the energy analysis, see Section 2.5. These fuels made up less than 1 percent of expenditure.

The largest component of operating costs is wages, which ranged between 18 percent and 54 percent, with a mean of 37 percent. The second largest component is energy ranging between 6 percent and 27 percent, with a mean of 20 percent.

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